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Unmanned Spaceflight.com _ Voyager and Pioneer _ Voyager Enters Final Frontier Of Solar System

Posted by: Sunspot Jun 3 2005, 10:47 PM

http://planetary.org/news/2005/voyager-update_t-shock-termination_0524.html

Voyager 1, the most distant human-made object in space, has crossed the termination shock, the last major threshold in the solar system, team members announced today at the annual American Geophysical Union (AGU) meeting in New Orleans, Louisiana.

Posted by: spaceffm Jun 4 2005, 01:45 AM

Do You think it is possible to see a picture towards the sun wikthout magnifictaion?
Is Voyager still this functionial?

Posted by: djellison Jun 4 2005, 05:51 AM

QUOTE (spaceffm @ Jun 4 2005, 01:45 AM)
Is Voyager still this functionial?
*


No, basically smile.gif

Doug

Posted by: edstrick Jun 4 2005, 08:35 AM

The instruments on the scan platforms have been turned off. The last camera use was the look back across the solar system that caught the "pale blue dot". The ultraviolet spectrometer was in use as a poor-man's ultraviolet astronomy spectroscopy satellite for some years, but was finally retired. Heaters on the instruments and scan platform gear-boxes are off so they've all cooled to various near-cryogenic temperature levels, far outside their design survivability ranges. Thermal contraction of materials has probably broken solder joints and the like.

The voyagers probably have not enough power to run anything on the scan platforms now, anyway, even if they weren't probably broken by the cooldown.

Posted by: PhilCo126 Nov 13 2005, 05:48 PM

I thought it would last untill 2015 before the first VOYAGER spacecraft will be in interstellar space ...

Posted by: ljk4-1 Nov 14 2005, 03:52 PM

QUOTE (PhilCo126 @ Nov 13 2005, 12:48 PM)
I thought it would last untill 2015 before the first VOYAGER spacecraft will be in interstellar space ...
*


I went to the official NASA/JPL Web site on the Voyagers and found this:

http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm

And if you go to the home Voyager page, they have links to the latest science data from the probes from this year. Go here and look on the left column under Latest Browse Data:

http://voyager.jpl.nasa.gov/

This page has a rundown of what the Voyagers will be doing through the year 2020, when it is thought they will finally be unable to power even a single instrument:

http://voyager.jpl.nasa.gov/spacecraft/spacecraftlife.html

Posted by: The Messenger Nov 14 2005, 07:08 PM

QUOTE (ljk4-1 @ Nov 14 2005, 08:52 AM)
I went to the official NASA/JPL Web site on the Voyagers and found this...

I pulled up some of data, the increase in cosmic ray count is an eye opener, at least doubling, if not more over the last two years. I am also intregued by the the fact that the plutonium powered system is producing more energy than expected. Over the short term, this can be written off as better-than-expected aging of the thermalcouples; but the trend looks like it is gnawing away at three sigma limits.

Wouldn't it be a hoot if radioactive half-lifes turn out to vary as a function of AU? Could the increase in cosmic rays be effecting the decay rate?

Posted by: deglr6328 Nov 14 2005, 08:23 PM

3-Sigma limits of what? Has anyone ever even studied thermoelectric junction degradation rate fluctuations over a period of 30 years?

Posted by: mike Nov 14 2005, 08:41 PM

I wouldn't complain if the increase in cosmic rays (or something else out there) was somehow recharging the power supply (employ a more scientific-sounding explanation if you like)..

Posted by: ljk4-1 Jan 11 2006, 10:32 PM

http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm

Voyager Mission Operations Status Report # 2005-11-11, Week Ending November 11, 2005

Command Transmission & Verification Operations

Voyager 1 command operations consisted of the uplink of a command loss timer reset on 11/08 [DOY 312/1625z]. The spacecraft received the command.

There were no Voyager 2 command operations due to the extended downtime of DSS-43.

Sequence Generation Operations

Continue sequence development of CCSL B131.

Data Return Operations

Voyager 1 Data Processing and Operations:

There were 83.2 hours of DSN scheduled support for Voyager 1 of which 28.1 hours were large aperture coverage. There was one schedule change made on 11/09 [DOY 313] when 3.5 hours of DSS-65 support was released to support MUSC. The total actual support for the period was 79.7 hours of which 28.1 hours were large aperture coverage. There were no significant outages during the period

Science instrument performance was nominal for all activities during this period. One frame of GS-4 data was recorded this week. A second frame of GS-4 data was recorded on day 309. The EDR backlog is 9 days.

Voyager 2 Data Processing and Operations:

There were 54.5 hours of DSN scheduled support for Voyager 2 of which 0 hours were large aperture coverage. There was one schedule change made on 11/09 [DOY 313] when 2.5 hours of DSS-45 support was released to support MUSC. The total actual support for the period was 52.0 hours of which 0 hours were large aperture coverage.

There was one significant outage of 0.7 hours on 11/08 [DOY 312] due to a sub-reflector problem at DSS-45 [DR C104604].

Science instrument performance was nominal for all activities during this period. One frame of GS-4 data was recorded this week. The EDR backlog is 8 days.

Flight System Performance

Voyager 1 performance was nominal during this report period. Activities included a PMPCAL and switching to Band Low Power on 11/9 (DOY 313/314).

Voyager 2 performance was nominal during this report period.

PROPELLANT/POWER CONSUMABLES STATUS AS OF THIS REPORT

Spacecraft
Consumption

One Week (Gm)
Propellant

Remaining (Kg)
Output

(Watts)
Margin

(Watts)

1
50.34*
28.58
292.9
35

2
7.87
30.49
294.5
41


*MAGROL 05-308/21:45

RANGE, VELOCITY AND ROUND TRIP LIGHT TIME AS OF 11/11/2005

Voyager 1
Voyager 2

Distance from the Sun (Km)
14,558,000,000
11,671,000,000

Distance from the Sun (Mi)
9,046,000,000
7,252,000,000

Distance from the Earth (Km)
14,669,000,000
11,736,000,000

Distance from the Earth (Mi)
9,115,000,000
7,292,000,000

Total Distance Traveled Since Launch (Km)
17,312,000,000
16,308,000,000

Total Distance Traveled Since Launch (Mi)
10,757,000,000
10,134,000,000

Velocity Relative to Sun (Km/sec)
17.162
15.610

Velocity Relative to Sun (Mi/hr)
38,390
34,919

Velocity Relative to Earth (Km/sec)
40.552
41.500

Velocity Relative to Earth (Mi/hr)
90,711
92,832

Round Trip Light Time (hh:mm:ss)
27:10:20
21:44:54

Posted by: Rob Pinnegar Jan 12 2006, 01:12 PM

QUOTE (ljk4-1 @ Jan 11 2006, 04:32 PM)
Distance from the Sun (Mi)
9,046,000,000
7,252,000,000


Looks like Voyager 1 will pass 100 AU pretty soon. Not a scientifically important point, but significant in its own way.

Posted by: ljk4-1 Feb 15 2006, 03:30 PM

Voyager Mission Status 11/18/2005 and 11/25/2005:

http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm

Feature video in the main Voyager page:

http://voyager.jpl.nasa.gov/index.html

'Voyager enters the Heliosheath' by the Voyager Project Scientist, Dr. Ed Stone.

Posted by: ljk4-1 Feb 22 2006, 05:12 PM

COSMIC RAY MYSTERY SOLVED
-------------------------

When Voyager 1 finally crossed the "termination shock" at the edge of
interstellar space in December 2004, space physicists anticipated the
long-sought discovery of the source of anomalous cosmic rays. These cosmic
rays, among the most energetic particle radiation in the solar system, are
thought to be produced at the termination shock - the boundary at the edge
of the solar system where the million-mile-per-hour solar wind abruptly
slows. A mystery unfolded instead when Voyager data showed 20 years of
predictions to be wrong.

...

The paper, "An Explanation of the Voyager Paradox: Particle Acceleration at a
Blunt Termination Shock," is available in the February 17 issue of the Geophysical
Research Letters.

http://spaceflightnow.com/news/n0602/19voyager/

Posted by: ljk4-1 Mar 14 2006, 04:00 PM

Astrophysics, abstract
astro-ph/0603318

From: Merav Opher [view email]

Date: Mon, 13 Mar 2006 19:30:59 GMT (539kb)

Effects of a Local Interstellar Magnetic Field on Voyager 1 and 2 Observations

Authors: Merav Opher, Edward C. Stone, Paulett C. Liewer

Comments: 12 pages, 5 figures

Journal-ref: Astrophysical Journal Letters v.640, 71, 2006

We show that that an interstellar magnetic field can produce a north/south asymmetry in solar wind termination shock. Using Voyager 1 and 2 measurements, we suggest that the angle $\alpha$ between the interstellar wind velocity and magnetic field is $30^{\circ} < \alpha < 60^{\circ}$. The distortion of the shock is such that termination shock particles could stream outward along the spiral interplanetary magnetic field connecting Voyager 1 to the shock when the spacecraft was within $\sim 2~AU$ of the shock. The shock distortion is larger in the southern hemisphere, and Voyager 2 could be connected to the shock when it is within $\sim 5~AU$ of the shock, but with particles from the shock streaming inward along the field. Tighter constraints on the interstellar magnetic field should be possible when Voyager 2 crosses the shock in the next several years.

http://fr.arxiv.org/abs/astro-ph/0603318

Posted by: dilo Mar 16 2006, 11:32 PM

From updated solar wind speed http://web.mit.edu/afs/athena/org/s/space/www/voyager/voyager_data/v100.gif, Voyager-2 experienced a repentine increase (more than 100 Km/s) at the end of February/beginning of March.
In my understanding, transition through termination shock should produce a dramatic wind speed decrease, so this is not the case... Anyway still intriguing, because even if in the past Voyager-2 already observed speed close to 500 Km/s, now increase seems more repentine and appear associated to one of the largest http://voycrs.gsfc.nasa.gov/cgi-bin/recent.pl spikes ever observed by the spacecraft...
Any suggestion?

Posted by: Rem31 Mar 25 2006, 03:13 AM

QUOTE (dilo @ Mar 17 2006, 12:32 AM) *
From updated solar wind speed http://web.mit.edu/afs/athena/org/s/space/www/voyager/voyager_data/v100.gif, Voyager-2 experienced a repentine increase (more than 100 Km/s) at the end of February/beginning of March.
In my understanding, transition through termination shock should produce a dramatic wind speed decrease, so this is not the case... Anyway still intriguing, because even if in the past Voyager-2 already observed speed close to 500 Km/s, now increase seems more repentine and appear associated to one of the largest http://voycrs.gsfc.nasa.gov/cgi-bin/recent.pl spikes ever observed by the spacecraft...
Any suggestion?

How bright is the light of the sun at the place where the pioneers and the voyagers are at (this) moment? Or is it completely dark there now ,please can you tell me that? Thanks.

Posted by: Rob Pinnegar Mar 25 2006, 06:40 PM

QUOTE (Rem31 @ Mar 24 2006, 08:13 PM) *
How bright is the light of the sun at the place where the pioneers and the voyagers are at (this) moment? Or is it completely dark there now ,please can you tell me that? Thanks.

Well, the apparent brightness of the Sun varies as the inverse square of your distance from the Sun. Right now Voyager 1 is about a hundred times farther from the Sun than we are. So that means that, as seen from Voyager 1, the Sun is about one ten-thousandth as bright as what we are used to.

That's still about 500 times brighter than a full Moon, though. So although the Sun would look like a star from Voyager 1, it would be a really, really bright star.

Posted by: dilo May 15 2006, 09:35 PM

Something is definitely happening around Voyager-2!
Last http://voyager.gsfc.nasa.gov/cgi-bin/recent.pl shows that, after 10 months of caothic behavior, density dropped to very low levels; in the meantime, http://web.mit.edu/afs/athena/org/s/space/www/voyager/voyager_data/v100.gif stopped the regular descent (after the step-up previously noticed) and started to go up and down on a hourly scale (density and velocity seems to have a complementary behaviour...).
I do not recall what exactly happened to Voyager-1 density data (any help?), but I strongly suspect termination shock is very close... or already passed!

Posted by: dilo May 15 2006, 09:47 PM

Based on Solar System Simulator, Voyager-2 is only 79.6AU from Sun: considering also the unfavorable heading direction, is too early for a termination shock encounter (but not impossible, it depends also from solar activity!).
Meanwhile, it is interesting to highlight that Voyager-1 is now only 130million Km from the 100 AU milestone! Should happens at mid August... I have to prepare some champagle bottle rolleyes.gif

Posted by: Bob Shaw May 15 2006, 09:53 PM

QUOTE (Rob Pinnegar @ Mar 25 2006, 07:40 PM) *
Well, the apparent brightness of the Sun varies as the inverse square of your distance from the Sun. Right now Voyager 1 is about a hundred times farther from the Sun than we are. So that means that, as seen from Voyager 1, the Sun is about one ten-thousandth as bright as what we are used to.

That's still about 500 times brighter than a full Moon, though. So although the Sun would look like a star from Voyager 1, it would be a really, really bright star.


Rob:

Any idea how far from the Sun the human eye can still see colour rather than using monochrome 'night' vision?

Bob Shaw

Posted by: Myran May 16 2006, 03:13 PM

QUOTE
Dilo wrote: .....but I strongly suspect termination shock is very close... or already passed!


What you retold makes me wonder if that might be the case, and Voyager 2 might have reached the heliopause. Thank you or the heads up.

Posted by: ljk4-1 May 23 2006, 08:56 PM

Podcast Advisory May 23, 2006

Voyager: Still Going Strong After Nearly 30 Years

NASA's twin Voyager spacecraft are beaming back new information about the final frontier of our solar system, including evidence of "potholes" in the turbulent zone near the edge.

A podcast, featuring an interview with Voyager Project Scientist Dr. Ed Stone of Caltech, is online at http://www.jpl.nasa.gov/multimedia/podcast/voyager-20060523/ . The interview includes information about the latest findings, as well as highlights from the past 29 years of the Voyagers' journeys through space.

More information on the Voyager spacecraft is available at http://voyager.jpl.nasa.gov/ and www.nasa.gov/voyager .

Voyager 1 and 2 launched in 1977 on a mission to study the outer planets of our solar system, and they are now on their way to becoming the first spacecraft to leave our solar system.

Additional JPL podcasts are at http://www.jpl.nasa.gov/multimedia/indexPod.cfm .

Posted by: climber May 23 2006, 09:47 PM

[quote name='ljk4-1' date='May 23 2006, 10:56 PM' post='55471']
Voyager 1 and 2 launched in 1977 on a mission to study the outer planets of our solar system, and they are now on their way to becoming the first spacecraft to leave our solar system.


I thought Pioneer 10 & 11 were considered been the first.
By the way, Ed Stone was already there at last encounter with Neptune back in 1989. He's got to have faith in what he does to carry out the VIM (is that correct Voyager Insterstellar Mission ?) since it's apparently look less rewarding after "The Grand Tour". Hat off Mister Stone.

Posted by: dilo May 23 2006, 10:20 PM

Climber, Pioneer didn't reached the heliopause because they are slower.
This is clear looking to distances from Sun, calculated by Solar System Simulator and ranked in descending order:
Voyager-1: 99.2 AU
Pioneer-10: 90.6 AU
Voyager-2: 79.7 AU
Pioneer-11: 69.9 AU
(hey, they are almost equally spaced in this moment!)
In particular, Pioneer-10 was surpassed by Voyager-1 several years ago and, anyway, now is inactive...

Thanks, ljk4-1 for the interview highlight. The words of Dr. Ed Stone confirm that Voyager entered in a new region as I suspected, but still to reach the heliopause which should be 5 AU ahead!

Posted by: ljk4-1 May 24 2006, 06:31 PM

Voyager 2 Detects Odd Shape of Solar System's Edge

http://www.space.com/scienceastronomy/060523_heliosphere_shape.html

Voyager 2 could pass beyond the outermost layer of our solar system, called the
"termination shock," sometime within the next year, NASA scientists announced at
a media teleconference today.

Posted by: climber May 24 2006, 10:02 PM

[quote name='dilo' date='May 24 2006, 12:20 AM' post='55486']
Climber, Pioneer didn't reached the heliopause because they are slower.
This is clear looking to distances from Sun, calculated by Solar System Simulator and ranked in descending order:
Voyager-1: 99.2 AU
Pioneer-10: 90.6 AU
Voyager-2: 79.7 AU
Pioneer-11: 69.9 AU
(hey, they are almost equally spaced in this moment!)
In particular, Pioneer-10 was surpassed by Voyager-1 several years ago and, anyway, now is inactive...


Thanks Dilo. Doesn't show very well in the numbers anyway.
Pioneer 10 deserve to has been the first one to be launched with an interstellar "destination" (as a by product), and Pionner 11 the second... and they will.

Posted by: PhilCo126 May 26 2006, 07:01 PM

The greatest traveller of all times ! wink.gif

Posted by: Analyst May 27 2006, 06:39 AM

Do you have a link to the press kit? Or a press kit etc. of any of the other encounters?

Analyst

Posted by: SigurRosFan May 27 2006, 09:06 PM

QUOTE (dilo @ May 15 2006, 11:47 PM) *
Based on Solar System Simulator, Voyager-2 is only 79.6AU from Sun: considering also the unfavorable heading direction, is too early for a termination shock encounter (but not impossible, it depends also from solar activity!).
Meanwhile, it is interesting to highlight that Voyager-1 is now only 130million Km from the 100 AU milestone! Should happens at mid August... I have to prepare some champagle bottle rolleyes.gif

Yes, it should happens on August 17, 2006!

- http://voyager.jpl.nasa.gov/science/Vgrlocations.pdf

Posted by: ljk4-1 Jun 1 2006, 02:46 PM

Voyager Data May Reveal Trajectory Of Solar System

Newport Beach CA (SPX) Jun 01, 2006

Nearly 30 years after launch, the two Voyager spacecraft are still operational and returning useful data. In their early years they produced some of the first close up images of the large outer planets.

http://www.spacedaily.com/reports/Voyager_Data_May_Reveal_Trajectory_Of_Solar_System.html

Posted by: ljk4-1 Jun 1 2006, 03:35 PM

PHYSICS NEWS UPDATE

The American Institute of Physics Bulletin of Physics News

Number 778 May 26, 2006 by Phillip F. Schewe, Ben Stein,
and Davide Castelvecchi www.aip.org/pnu

THE MISSHAPEN SOLAR SYSTEM. Having traveled far beyond the planets
in their 28.5-year journey, the two Voyager spacecraft are providing
new information on the heliosphere, the teardrop-shaped bubble that
separates the solar system from interstellar space. At this week's
Joint Assembly Meeting in Baltimore of the American Geophysical
Union (AGU) and several other geophysics-related societies, Ed Stone
of Caltech reported that the heliosphere is deformed, according to
Voyager observations, with the teardrop's rounded edge bulging at
the top (the northern hemisphere of the solar system) and squashed
at the bottom (the southern hemisphere). (See pictures and movies at
http://www.nasa.gov/vision/universe/solarsystem/voyager_2006agu.html
) As Rob Decker of Johns Hopkins University Applied Physics
Laboratory explained, the asymmetry is due to a magnetic field from
interstellar space pushing on the southern hemisphere. The field is
about 1/100,000 the strength of Earth's field but its effects can be
felt for billions of miles, since it is acting over a large area on
the very dilute gas at the solar system's edge.

The interstellar field even squashes an important spherical zone
inside the heliosphere, called the termination shock. Analogous to
the circle that forms when water splatters on a sink, the
termination shock represents the boundary at which the rapidly
traveling solar wind (the stream of charged gas from the sun) slows
down abruptly and piles up. Voyager 2's measurements indicate that
the southern part of the termination sphere might be a billion miles
closer to the sun than the northern part. Moreover, forces from the
solar wind cause the termination shock to breathe in and out roughly
every dozen years. Voyager 1 has already ventured beyond the
termination shock, to the heliosheath, the region where solar wind
and interstellar gas mix. So in a way, the end of the solar system
is not clearly defined. Stone guesses it could be another 10 years
(3-4 billion miles) before the two spacecraft pass through the
heliopause (the very outermost boundary of the heliosphere) and
enter purely interstellar space. The spacecraft have about another
15 years of power left in them. (Session SH02 at meeting; see
http://www.agu.org/meetings/ja06/?content=search)



QUOTE (Analyst @ May 27 2006, 02:39 AM) *
Do you have a link to the press kit? Or a press kit etc. of any of the other encounters?

Analyst


There is the Voyager Neptune Travel Guide online:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900004096_1990004096.pdf

Other online Voyager documents from NASA can be found here by
scrolling all the way down (the spacecraft are listed in alphabetical order):

http://www.geocities.com/bobandrepont/unmannedpdf.htm

Posted by: ljk4-1 Jun 9 2006, 02:59 AM

Voyager Reports March 3, 2006 to March 24, 2006 Available

http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm

Posted by: MCS Sep 23 2006, 09:40 AM

There's a http://science.nasa.gov/headlines/y2006/21sep_voyager.htm at science.nasa.gov about some of the things Voyager 1 has found within the heliosheath. Magnetic turbulence, a slower than expected solar wind, and unexpected anomalous cosmic ray intensities are the main things mentioned. I hope this helps make the case for continued funding.

Posted by: dilo Apr 17 2008, 04:45 PM

This is not exactly a new: Voyager 2 entered the heliosheath on August 30, 2007.
http://voyager.jpl.nasa.gov/news/voyager_squashed.html
However, incredibly, I completely ignored the event on this page and only now I "discovered" it by looking to these eloquent plots:
http://web.mit.edu/space/www/voyager/voyager_data/overview_plot_recent.gif
(in the past, I was looking more often to these data but in recent months I'm more and more busy mad.gif ).
Looking to this Forum section, it seems nobody noticed it... cannot believe anyone missed it like me! blink.gif

Addendum: based on Solar System Simulator, cross occurred at 83.7 AU from sun, about 10 AU closer than Voyager-1!

Posted by: dilo Apr 17 2008, 09:11 PM

Further infos: As you know, contrary to his brother, Voyager 2 has a working Plasma Science instrument that can directly measure the velocity, density and temperature of the solar wind.
I downloaded hourly data from ftp://space.mit.edu/pub/plasma/vgr/v2/ha/key/ plasma science page. Following plots shows trend of measured proton speed, thermal speed (temperature) and density (second plot is a temporal enlargement covering the transition (window is 0.1 years or 36.5 days large):


As mentioned in the article, Voyager-2 had at least five shock crossings over a couple of days; perhaps they are the density peaks visible in second plot. QUESTION: why there is a so large hiatus (11 days) in the data immediately after this event??? Too strange for a coincidence!
They also found a much lower temperature beyond the shock than was predicted; anyway, based on following scatter plots (referred to data in the narrow temporal window of second plot above) there is a good correlation (almost inverse-square) between these twoparameters:


Any comment is welcomed!

Posted by: scalbers Apr 17 2008, 09:31 PM

I saw a nice talk that Ed Stone gave on this topic three days ago. It will be interesting to follow along for a decade or so to see what the magnetic field looks like when Voyager gets completely into the interstellar medium.

Posted by: brellis Jul 2 2008, 08:18 PM

(edit: of course this is old news to UMSF thread readers!)

The solar system is 'dented' as reported in this http://www.cnn.com/2008/TECH/space/07/02/solarsystem.ap/index.html.

I'm curious about how they refer to 'north' and 'south', and whether the motion of the Sun through the Milky Way impacts the escape velocities of the Voyagers.

(2nd edit: I thought I had asked the velocity question somewhere before, and found that dmuller provided insight in http://www.unmannedspaceflight.com/index.php?s=&showtopic=2080&view=findpost&p=119460 over in the New Horizons thread.

thank you dmuller!)

Posted by: Paolo Jul 27 2008, 02:12 PM

In the latest issue of Astronomy & Astrophysics
http://www.aanda.org/articles/aa/abs/2008/31/aa09555-08/aa09555-08.html

Posted by: Fran Ontanaya Sep 24 2008, 06:48 AM

You may want to look at Voyager 2 wind speed data:

http://web.mit.edu/afs/athena/org/s/space/www/voyager/voyager_data/voyager_data.html

There was a nice spike last month, from ~225 km/s to ~325 km/s, the fastest speed since it crossed the termination shock.

Posted by: PhilCo126 Oct 27 2008, 07:07 PM

http://www.nature.com/nature/videoarchive/voyager/

Posted by: Paolo Nov 1 2008, 04:15 PM

The lhttp://www.aanda.org/index.php?option=toc&url=/articles/aa/abs/2008/43/contents/contents.html has some articles about heliospheric science, including results from Voyager, Ulysses, Cassini, Nozomi etc.

Posted by: dilo Nov 1 2008, 09:14 PM

Grazie, Paolo. Very interesting!

Posted by: Enceladus75 Nov 3 2008, 06:07 PM

I'm curious to know what science instruments are still functional on each Voyager. I'm aware that the cameras are now permanently turned off Voyager 2 has some more capability at measuring fields and particles over Voyager 1, but what instruments are actually still operational?

And for how long are they expected to remain operational?

Posted by: Fran Ontanaya Nov 3 2008, 06:25 PM

About lifetime:

http://voyager.jpl.nasa.gov/spacecraft/spacecraftlife.html


Posted by: dilo Nov 3 2008, 06:41 PM

and about instruments (from wikipedia):
As of the present date, the Voyager 2 and Voyager 1 scan platforms, including all of the platform instruments, have been powered down. The ultraviolet spectrometer (UVS) on Voyager 1 was active until 2003, when it too was deactivated. Gyro operations will end in 2010 for Voyager 2 and 2011 for Voyager 1. Gyro operations are used to rotate the probe 360 degrees six times a year to measure the magnetic field of the spacecraft, which is then subtracted from the magnetometer science data.

Posted by: Enceladus75 Nov 3 2008, 07:42 PM

Thanks guys. So it seems like both Voyagers will still have most of the fields and particles instruments active for the next decade or so.

Posted by: dilo Nov 4 2008, 06:24 AM

Yes.
More precisely, with the exception of the Voyager 1 Plasma Science instrument (which is turned off to accommodate UVS observations), all instruments are working well and are capable of continuing operations at least until 2020. However, due to termination of gyro operations about 7 years from now, it will be impossible to calibrate the magnetometer instrument and, more important, spacecrafts could loose orientation anticipating communications blackout with Earth... so, let's cross our fingers!

Posted by: Barnard Sep 30 2009, 09:23 AM

QUOTE (ljk4-1 @ Jun 9 2006, 03:59 AM) *
Voyager Reports March 3, 2006 to March 24, 2006 Available

http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm


I had a look at this page today and it seems the last report was made on the 31st of July? Is there a problem with the probes?

Posted by: remcook Sep 30 2009, 09:57 AM

They always update these pages in batches with some time delay. No worries.

Posted by: ZLD Dec 13 2010, 11:26 PM

Voyager 1 Sees Solar Wind Decline; Edges Closer to Interstellar Space (2010-12-13)

http://solarsystem.nasa.gov/news/display.cfm?News_ID=36121

Posted by: brellis Dec 14 2010, 03:29 AM

From the 12/14 http://www.spacedaily.com/reports/Voyager_Reaches_Interstellar_Space_As_Solar_Wind_Slows_To_Zero_999.html (wait - that's tomorrow! hehe)

QUOTE
Scientists suspect the solar wind has been turned sideways by the pressure from the interstellar wind in the region between stars.


Questions for more studied UMSFers: The space daily article has an image that implies our sun's heliosheath has a huge tail. Is that tail due to the sun's motion around the galactic center? Is Voyager 1 at the 'front' edge? Is Voyager 2 heading down the tail side?

Posted by: ZLD Dec 14 2010, 04:28 AM

I think this article could help:
http://www.sciencedaily.com/releases/2009/10/091016142056.htm

Also:
http://www.sciencedaily.com/releases/2009/10/091016101807.htm

Posted by: g4ayu Dec 14 2010, 12:14 PM

Just noticed that it's the top read news story on the BBC News website.


Posted by: rogelio Apr 14 2011, 12:13 PM

Nice article about Edward Stone in today's LA Times:

"Voyager 1 on the edge, and so is he"

http://www.latimes.com/news/local/la-me-0414-ed-stone-20110412,0,4527527.story



Posted by: jasedm Apr 14 2011, 04:43 PM

Thanks Rogelio - nice article

Ed has quite some CV over the last four decades!!

I sincerely hope he's around to see V1 coast into interstellar space proper.

Jase

Posted by: mchan Jun 10 2011, 02:11 AM

http://science.nasa.gov/science-news/science-at-nasa/2011/09jun_bigsurprise/

Intriguing "frothy magnetic bubbles".

Posted by: MarcF Jun 16 2011, 08:38 AM

Some good news from outer space :

"Voyager 1 could cross over into the frontier of interstellar space at any time and much earlier than previously thought"

http://voyager.jpl.nasa.gov/news/recalculating_space.html

Links to the journal Nature :
http://www.nature.com/news/2011/110615/full/news.2011.370.html

http://www.nature.com/nature/journal/v474/n7351/pdf/nature10115.pdf

Best regards,
Marc.

Posted by: jgoldader Jul 26 2011, 04:52 AM

Hi all,

I'm working on an article on the Voyagers, and have noticed that the last weekly status updates on the Voyager website were published in April. Does anybody know if they're normally sent up in batches?

Thanks
Jeff

Posted by: remcook Jul 26 2011, 07:21 AM

Yes, last time I checked, they get put on the website in large batches.

Posted by: Paolo Dec 2 2011, 06:07 AM

today on Science express: http://www.sciencemag.org/content/early/2011/11/30/science.1197340.abstract

Posted by: remcook Dec 2 2011, 08:37 AM

Great, still doing good science!

Posted by: JTN Dec 3 2011, 01:30 AM

Curious to know if the measurements form anything that could be described as an image. Does the full article say -- anyone have Science access? (I can't tell from the free http://www.sciencemag.org/content/early/2011/11/30/science.1197340/suppl/DC1.)

Measurements are said to be taken with the ultraviolet spectrometer (UVS). http://vega.lpl.arizona.edu/voyager_uvs/instrument.html quotes FOV as 0.10° × 0.87°, so maximum spatial resolution would be pretty coarse. From hints in the supplement, I guess the data are much coarser.

http://voyager.jpl.nasa.gov/science/index.html (date unknown) says: "data is being collected from the Ultraviolet Spectrometer Subsystem (UVS). While there are no science investigation teams associated with this instrument, the captured data is made available to interested scientists." If this was true at the time the relevant measurements were taken, I guess they might not have been chosen with this investigation in mind?

http://www.newscientist.com/article/dn21233-voyager-space-probes-show-outsiders-view-of-milky-way.html says the instruments have since been turned off (corroborated by http://voyager.jpl.nasa.gov/science/thirty.html: V1 1998, V2 2002).

Posted by: stevesliva Dec 3 2011, 02:49 AM

http://vega.lpl.arizona.edu/voyager_uvs/instrument.html

It's pulse counting on the 128 channels that form the spectrum.

From the supplement:

QUOTE
For our specific purpose of a high precision and bias-free Ly determination we have devised a new reduction and
analysis pipeline, improved from the technique used earlier (33). The Voyager UVS (Ultra-Violet Spectrometer)
has a field of view of 0.1x0.87 defined by a mechanical grill collimator. Light that passes through the collimator
reaches a concave grating, which disperses and focusses the light onto the microchannel plate (MCP) detector. A
single photo-electron created at the input of the MCP generates a pulse of many electrons at the output, and this
charge is collected on a linear array of 128 elongated anodes (channels) that correspond to the 540 to 1700 Å range.
One anode covers 9.26 Å. Charges on the anodes are periodically sampled and subjected to threshold detection;
detected events are summed into 128 corresponding memory locations to form a spectrum.


So no, not really a picture. And that is coupled with two Azimuth directions.

Posted by: Paolo Dec 3 2011, 08:54 AM

QUOTE (JTN @ Dec 3 2011, 02:30 AM) *
Curious to know if the measurements form anything that could be described as an image. Does the full article say -- anyone have Science access? (I can't tell from the free http://www.sciencemag.org/content/early/2011/11/30/science.1197340/suppl/DC1.)


there is an image in the paper (fig. 2, for those having access) showing "Scan data point directions superimposed on" a hydrogen-alpha map of the sky. Scan data points are colorized to indicate "the intensity of the continuum, with red indicating its absence and blue the most intense".
no real image, actually...

as for the date scans were taken, Voyager 1 operated between 1993 and mid-2003 and V2 between 1993 and mid-1998.

Posted by: MarcF Dec 13 2011, 10:43 AM

It's getting really exiting !! Not long to wait now before historical entry into the interstellar medium !!
NASA'S VOYAGER HITS NEW REGION AT SOLAR SYSTEM EDGE
http://voyager.jpl.nasa.gov/news/new_region.html

Best regards,
Marc.

Posted by: hendric Dec 13 2011, 07:03 PM

QUOTE (MarcF @ Dec 13 2011, 04:43 AM) *
It's getting really exiting


Best UMSF Freudian slip ever. smile.gif

Posted by: MarcF Dec 13 2011, 08:37 PM

Hehehe ! Oups !! This loss of C was really not deliberate !!

Posted by: volcanopele Dec 13 2011, 09:59 PM

I wouldn't call that a Freudian slip, but that certainly goes on the list of best puns (albeit unintentional) of the year.

Posted by: ups Dec 17 2011, 07:14 PM

It's amazing that the science coming from the Voyagers hasn't really egressed in the 30+ years they've been in service.

Posted by: MarcF Jun 20 2012, 07:03 PM

Ever closer... rolleyes.gif
http://www.jpl.nasa.gov/news/news.cfm?release=2012-177
Best regards,
Marc.

Posted by: dilo Jun 21 2012, 04:58 AM

QUOTE (MarcF @ Jun 20 2012, 08:03 PM) *
Ever closer...

I think they refers, in particular, to high energy proton flux:

extracted from here:
 v1_1d_08_on_8ion.pdf ( 106.9K ) : 586

Posted by: MarcF Aug 7 2012, 03:49 PM

And more signs that "we" are almost in the interstellar medium...
http://voyager.jpl.nasa.gov/news/signs_changing_fast.html
Best regards,
Marc.

Posted by: dilo Sep 1 2012, 07:04 AM

At the end of August we had another two drops of low-energy protons, even deeper than one month ago!
http://sd-www.jhuapl.edu/VOYAGER/images/vgr_qlp/v1_lecp/v1_pl08_1d_avg_09_on.pdf

Posted by: Astro0 Sep 5 2012, 07:13 AM

Voyager 1 marks 35 years since launch and joining Voyager 2 on the Grand Tour of the Solar System.
http://voyager.jpl.nasa.gov/news/voyager_35.html

A new banner to mark the milestone smile.gif

Sail on lil' Voyagers! Sail on!

Posted by: RoverDriver Sep 5 2012, 07:33 AM

I think that Voyagers are the coolest mission. Whenever I go to the Von Karman here at JPL where they have a replica I'm always amazed by their size.

Paolo

Posted by: Paolo Sep 5 2012, 06:16 PM

on the next issue of Nature
http://www.nature.com/news/voyager-s-long-goodbye-1.11348
http://www.nature.com/nature/journal/v489/n7414/full/nature11441.html
the latter requires a subscription

Posted by: jasedm Sep 5 2012, 06:42 PM

QUOTE (RoverDriver @ Sep 5 2012, 08:33 AM) *
I think that Voyagers are the coolest mission.

Paolo


Seconded.

Posted by: dilo Sep 14 2012, 01:13 PM

I think this combined plot speaks by itself:


V1 is definitively inside a totally new region...
Source: http://voyager.gsfc.nasa.gov/heliopause/heliopause/recenthist.html

Posted by: TheAnt Sep 30 2012, 06:07 PM

It really looks like it.
That particle/proton rate have stayed low for 2 more weeks, whereas the galactic cosmic rays continue to climb slowly.
And turning of the spacecraft to look for any possible sideway movement did show that the particles were not moving sideways either.
(Also described in the summary linked by Paolo.)

Isn't that exactly the conditions to expect at the boundary of the heliopause?

Now data from IBEX suggest there might be no bow shock zone at all. So all will depend on how deep this area might be, after that Voyager 1 might very well be in true Interstellar space.

Related story http://www.nature.com/news/2008/080702/full/454024a.html

Posted by: dilo Sep 30 2012, 06:49 PM

Thanks for the link, TheAnt!
This recall me to update the plot:


After two more weeks, initial impression became a robust trend!

Posted by: EdTruthan Nov 30 2012, 07:27 PM

NASA will host a media teleconference at 11 a.m. PST (2 p.m. EST) on Monday, Dec. 3, to discuss the latest findings and travels of NASA's Voyager 1 spacecraft. http://www.jpl.nasa.gov/news/news.php?release=2012-379&cid=release_2012-379

Posted by: Floyd Nov 30 2012, 10:01 PM

Dilo
Are your graph labels are correct >70 and >0.5 not >70 and <0.5??

Posted by: Hungry4info Nov 30 2012, 10:43 PM

That's what the original graphs say.
http://voyager.gsfc.nasa.gov/heliopause/heliopause/v1la1.html
http://voyager.gsfc.nasa.gov/heliopause/heliopause/v1pgh.html

Posted by: Floyd Dec 1 2012, 03:33 AM

What am I missing. >70 is also >0.5, so how can >70 be going up the last month and >0.5 be going down????? Never mind--two different detectors measuring different types of particles, not one detector measuring two energy ranges.

Posted by: djellison Dec 1 2012, 10:17 AM

However - the value of >70 is small compared to >0.5

It's risen from only 2 to 2.3
Whereas the >0.5 has dropped from 25 to about 2.3

i.e. - the amount of particles between 0.5 and 70 has dropped to essentially zero.

Posted by: dilo Dec 1 2012, 04:27 PM

QUOTE (Floyd @ Nov 30 2012, 11:01 PM) *
Dilo
Are your graph labels are correct >70 and >0.5 not >70 and <0.5??

Labels were correct (copied from original) but their postions on vertical axes were wrong! This is the correct (and updated) 1-year trend:

Sorry for mistake!

Posted by: Explorer1 Dec 3 2012, 07:03 PM

Starting here: http://www.ustream.tv/nasajpl2

Nothing at the usual NASA link....

Posted by: Tesheiner Dec 3 2012, 07:31 PM

News release: http://www.jpl.nasa.gov/news/news.php?release=2012-381.

QUOTE
December 03, 2012

PASADENA, Calif. -- NASA's Voyager 1 spacecraft has entered a new region at the far reaches of our solar system that scientists feel is the final area the spacecraft has to cross before reaching interstellar space.
...

Posted by: 0101Morpheus Dec 6 2012, 08:07 PM

So much for there being a clear cutoff point rolleyes.gif

Posted by: djellison Dec 7 2012, 02:26 AM

What would you call this?
http://voyager.gsfc.nasa.gov/GIF/v1la.12m.gif

Posted by: Explorer1 Dec 7 2012, 06:49 AM

I think this time they're very sure this is the last section before true interstellar space (in terms of particles, not gravity). It was described as the 'off-ramp' to the stars in the recent teleconference. And the team will know it when they see it.
Once Voyager 2 crosses into this same area, we might even be able to guesstimate the large-scale shape of this 'highway'.

Posted by: djellison Dec 7 2012, 12:07 PM

There will be no sharp cut off of gravity - why do you mention that?

Posted by: 0101Morpheus Dec 7 2012, 05:27 PM

What I meant is that the scientists told us there was a clear boundary between the heliosphere and the outside. First they said there was a blow shock. Now we know the Sun doesn't have one. Then they said that the boundary would be when the solar wind stopped and there would be a sharp increase in cosmic rays. And thats what we've seen. But now they say were still inside the heliosphere because of the magnetic orientation. This new "in-between" area.

The heliosphere is the edge of the suns magnetic field. I was led to think there would be a sharp boundary. Now it seems to depend of interpretation. Is the edge where the influx of cosmic rays begins, or is it when the sun's magnetic field gives way to the galactic magnetic field? Thats all.

Posted by: Explorer1 Dec 7 2012, 05:28 PM

I was replying to 0101Morpheus about whether there's a clear transition into interstellar space which the heliopause crossing will be. Yet it really depends on our definitions of solar system; the sun's gravitational influence will be felt much farther, tens of thousands of AU, while the high energy particle environment can and does change rapidly, as this recent discovery shows. The Oort cloud would be 'outside' our solar system by the latter particle definition, but clearly still gravitationally bound to the Sun.

Posted by: 0101Morpheus Dec 7 2012, 05:32 PM

Seems we got our replies mixed up. rolleyes.gif

Yes I know the sun's gravity doesn't stop. You can keep going for a light year and still be inside its hills sphere.

Posted by: TheAnt Dec 24 2012, 09:17 PM

In the data for Voyager 2 we got a dip for the particle flux now in the first week of December then it had a small peak, to fold back down in about the same pace in the last days.
This might be similar as what we did see for V1 in August.

However this is one "stay tuned" post of mine for those interested, a heads up that also V2 might get close to the boundary but that it's not quite there yet.
http://voyager.gsfc.nasa.gov/heliopause/heliopause/v2la1.html

Posted by: djellison Dec 24 2012, 09:34 PM

V2 is clearly in a very different environment to V1. V2 has had a very gradual decline over the past year to about 50% of initial levels. V1 was almost static at a fixed level until a very sudden and rapid decline by an order of magnitude in literally a day that bounced back and forth a little then dropped for good. Fascinating.


Posted by: Explorer1 Dec 25 2012, 12:34 AM

Until New Horizons gets out there, these two are the only data points we have on what is certain to be complex large scale structures. Glad both are still functioning.

Posted by: stevesliva Dec 25 2012, 02:40 AM

QUOTE (Explorer1 @ Dec 24 2012, 07:34 PM) *
Until New Horizons gets out there, these two are the only data points we have on what is certain to be complex large scale structures. Glad both are still functioning.


No magnetometer on NH, though. Going to be a very long time until another magnetometer heads out there. (Comments about exactly how far NH will get aside.)

Posted by: TheAnt Jan 1 2013, 10:50 AM

QUOTE (djellison @ Dec 24 2012, 10:34 PM) *
V2 is clearly in a very different environment to V1.


My little personal hypothesis is that it is the same environment, the graph certainly dropped like a rock for V1 - which made me pay attention that something had happened. V1 are heading in a direction nearly bulls eye on the solar apex (the direction which the sun are travelling) - so the sphere might be somewhat flattened there and the border zone itself compressed.
But that V2 are entering it at a point nearly 90 degrees from the solar apex and so the process will take a longer time.

Since my post the particle count have started to drop down again - but as said, my post were merely a heads-up I am fully aware from my own work not to build intricate theories on just a hump in a graph. =)

Posted by: TheAnt Mar 13 2013, 09:10 PM

I have to admit bafflement for how the data have turned out. The particle count went down until early January which suggested a slower but continued decrease, after that it have been climbing up and approaches the average level. So djellison might have been right that the environment here are quite different indeed. I abandon any pet hypothesis gladly when there's a chance for something new, interesting or unexpected. =)




Posted by: brellis Mar 14 2013, 05:20 AM

ack, I have some more innocent questions:

Are there interstellar elements still floating inside the solar system? Towards us? Has Voyager 1 and/or 2 helped determine that distinction?

Posted by: TheAnt Mar 14 2013, 05:44 PM

QUOTE (brellis @ Mar 14 2013, 06:20 AM) *
ack, I have some more innocent questions:

Are there interstellar elements still floating inside the solar system? Towards us? Has Voyager 1 and/or 2 helped determine that distinction?


Oh there have been several spacecraft that have detected interstellar particles IBEX and Ulysses are two of those, the Stardust mission were to collect interstellar material, and I tend to think that also the Deep impact/EPOXI spacecraft did enter a stream of material thought to have originated outside the solar system. So there might be plenty more to find also if future spacecraft are provided with instruments to detect such.

Posted by: MarcF Mar 21 2013, 09:14 AM

False alarm :-(
http://voyager.jpl.nasa.gov/news/voyager_update.html

Posted by: TheAnt Mar 21 2013, 04:48 PM

You had me wonder for a bit, then I found that the NASA disclaimer seem to be referring to http://www.agu.org/news/press/pr_archives/2013/2013-11.shtml.

Though they do not say with certainty that Voyager are in interstellar space: "However, Webber notes, scientists are continuing to debate whether Voyager 1 has reached interstellar space or entered a separate, undefined region beyond the solar system."

Edit: And the headline in the piece I linked were changed to the more neutral "...entered a new region of space" a short while after my post were made.

And here's thehttp://onlinelibrary.wiley.com/doi/10.1002/grl.50383/abstract;jsessionid=A7F39A335A811063564AC1DE48D5D80D.d03t02in preprint.

Posted by: Mongo Jun 27 2013, 07:50 PM

http://phys.org/news/2013-06-solar-edge-voyager.html

QUOTE
Data from NASA's Voyager 1 spacecraft continues to provide new insight on the outskirts of our solar system, a frontier thought to be the last that Voyager will cross before becoming the first man-made object to reach interstellar space.

In papers published this week in the journal Science, scientists from the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., and other Voyager partner institutions provide more clarity on the region they named the "magnetic highway" in December 2012. Cruising through what scientists describe as a curious, unexpected charged-particle environment, Voyager has detected, for the first time, low-energy galactic cosmic rays, now that particles of the same energy from inside the bubble around our Sun disappeared. As a result, Voyager now sees the highest level so far of particles from outside our solar bubble that originate from the death of other nearby stars.

"Voyager 1 may be months or years from leaving the solar system—we just don't know," says APL's Stamatios Krimigis, principal investigator for Voyager's Low-Energy Charged Particle (LECP) instrument. "But the wait itself is incredibly exciting, since Voyager continues to defy predictions and change the way we think about this mysterious and wonderful gateway region to the galaxy."

Voyager 1 and 2 were launched in 1977 and between them visited Jupiter, Saturn, Uranus and Neptune. Since 1990, the twin spacecraft have been on their Interstellar Mission, on track to leave the heliosphere, which is the bubble of magnetic field and charged particles the Sun blows around itself. On Aug. 25, 2012, when Voyager 1 was about 11 billion miles (18 billion kilometers) from the Sun, the spacecraft reached the so-called magnetic highway where charged particles from inside the heliosphere zoomed out along the magnetic field as cosmic rays from far outside zoomed in. The lack of a detectable change in the direction of that magnetic field, however, convinced scientists that Voyager remained within the Sun's influence.

The new Science papers focus on observations from the summer and fall of 2012 by LECP as well as Voyager 1's Cosmic Ray and Magnetometer instruments, with additional LECP data through April 2013.

"The most dramatic part was how quickly the solar-originating particles disappeared; they decreased in intensity by more than 1,000 times, as if there was a huge vacuum pump at the entrance ramp onto the magnetic highway," says Krimigis. "We have never witnessed such a decrease before, except when Voyager 1 exited the giant magnetosphere of Jupiter, some 34 years ago."

"Surprisingly, the traveling direction of the 'inside' charged particles in this region made a difference, with those moving straightest along the magnetic field lines decreasing most quickly. Those that moved perpendicular to the magnetic field did not change as quickly," adds LECP Co-investigator Robert Decker, also of APL. The cosmic rays from outside, moving along the field lines, were somewhat more intense than those moving perpendicular to the field, and this imbalance varied significantly with time during the eight months since "It is this time-varying behavior of the cosmic rays that tells us that we're still in a region controlled by our Sun," says APL's Edmond Roelof, also an LECP co-investigator.

The multidimensional measurements speak to the unique abilities of the LECP detector, designed at APL in the 1970s. It includes a stepper motor that rotates the instrument through 45-degree steps every 192 seconds, allowing it to gather data in all directions and pick up something as dynamic as the solar wind and galactic particles. The device, designed and tested to work for 500,000 steps and last four years, has been working for nearly 36 years and well past 6 million steps.


http://www.sciencemag.org/content/early/2013/06/26/science.1235451.abstract

QUOTE
Magnetic fields measured by Voyager 1 (V1) show that the spacecraft crossed the boundary of an unexpected region five times between days 210 and ~238 in 2012. The magnetic field strength B increased across this boundary from ≈0.2 nT to ≈0.4 nT, and B remained near 0.4 nT until at least day 270, 2012. The strong magnetic fields were associated with unusually low counting rates of >0.5 MeV/nuc particles. The direction of B did not change significantly across any of the 5 boundary crossings; it was very uniform and very close to the spiral magnetic field direction, which was observed throughout the heliosheath. The observations indicate that V1 entered a region of the heliosheath (“the heliosheath depletion region”), rather than the interstellar medium.


http://www.sciencemag.org/content/early/2013/06/26/science.1235721.abstract

QUOTE
We report measurements of energetic (>40 keV) charged particles on Voyager 1 (V1) from the interface region between the heliosheath (HS), dominated by heated solar plasma, and the local interstellar medium (LISM) expected to contain cold nonsolar plasma and the galactic magnetic field. Particles of solar origin at V1, located at 18.5 billion km (123 AU) from the Sun, decreased by a factor >103 on 25 August 2012, while those of galactic origin (cosmic rays) increased by 9.3% at the same time. Intensity changes appeared first for particles moving in the azimuthal direction and were followed by those moving in the radial and antiradial directions with respect to the solar radius vector. This unexpected heliospheric "depletion region" may form part of the interface between solar plasma and the galaxy.


http://www.sciencemag.org/content/early/2013/06/26/science.1236408.abstract

QUOTE
On 25 August 2012, Voyager 1 was at 122 astronomical units when the steady intensity of low-energy ions it had observed for the last 6 years suddenly dropped for a third time and soon completely disappeared as the ions streamed away into interstellar space. Although the magnetic field observations indicate that Voyager 1 remained inside the heliosphere, the intensity of cosmic ray nuclei from outside the heliosphere abruptly increased. We report the spectra of galactic cosmic rays down to ~3 × 106 electron volts per nucleon, revealing H and He energy spectra with broad peaks from 10 × 106 to 40 × 106 electron volts per nucleon and an increasing galactic cosmic ray electron intensity down to ~10 × 106 electron volts.

Posted by: PDP8E Jun 27 2013, 09:44 PM

Thanks for pointing out that update Mongo,

a little back-of-the-envelope math... V1 will have traveled 1% of the distance to the nearest star, on or about the year 2727 ( EDIT: not 2377 ... I sharpened my pencil)

BTW, its not pointing at the nearest star, it is heading towards the vicinity of the Solar Apex (the direction of the Sun's motion relative to nearby stars, or currently someplace southwest of the star Vega). Voyager 1 will leave the solar system aiming toward the constellation Ophiuchus.

From NASA:
In the year 40,272 AD, Voyager 1 will come within 1.7 light years of an obscure star in the constellation Ursa Minor (the Little Bear or Little Dipper) called AC+79 3888

V1 is only 17.18 light-hours from the Sun at the moment.

Voyager 2 is also escaping the solar system to the south toward the constellations of Sagitarrius and Pavo.
In about 40,000 years, Voyager 2 will come within about 1.7 light years of a star called Ross 248, a small star in the constellation of Andromeda

also see:

http://www.heavens-above.com/SolarEscape.aspx

Posted by: Mongo Jun 28 2013, 12:19 AM

QUOTE (PDP8E @ Jun 27 2013, 10:44 PM) *
V1 is only 17.18 light-hours from the Sun at the moment.

That's 0.00196 light years from the Sun!

Well, it's a start...

Posted by: TheAnt Jun 30 2013, 12:21 PM

Voyager 1 might indeed be close to the Interstellar boundary now.

Yet it's only a 2 degree shift in direction of the magnetic field, and if I read this right most cosmic rays are still moving along the magnetic fieldlines. Which suggest they have been affected by it for some duration while approaching our solar system.

So even though I got very enthusiastic about the magnetic highway and that it might be a herald of interstellar space close at hand. There might be some reason to not starting to yell 'Are we there yet?' wink.gif

http://www.jpl.nasa.gov/news/news.php?release=2013-209

Posted by: TheAnt Aug 17 2013, 05:15 PM

Voyager 1 have now left the Solar system according to a study.

http://www.umdrightnow.umd.edu/news/voyager-1-has-left-solar-system

Posted by: TheAnt Aug 24 2013, 02:53 PM

And another item on the question if Voyager 1 is in interstellar space or not.
Now described as 'competing models' it all is a sign of good science work on the matter.

The magnetic lines from the sun do connect to the galactic magnetic field as described
Is as far as I understand it the 'magnetic highway' that been noted.
In addition, IBEX have indeed shown that there's no bow shock, so that is consistent with the alternative hypothesis.

http://www.sciencedaily.com/releases/2013/08/130821150652.htm

Posted by: Explorer1 Sep 12 2013, 05:45 PM

Voyager press conference in 15 minutes! Regarding an article in Science embargoed until today.
Streaming here: http://www.youtube.com/watch?v=uBqYErSvi6A

EDIT: Interstellar space confirmed! http://www.jpl.nasa.gov/news/news.php?release=2013-277

Posted by: Paolo Sep 12 2013, 06:07 PM

as Science titles: http://www.sciencemag.org/content/341/6151/1158.summary
for the lucky having full access here is the paper http://www.sciencemag.org/content/early/2013/09/11/science.1241681.abstract

Posted by: djellison Sep 13 2013, 05:36 AM

Science (as well as the BBC, CNN, infact almost everyone) makes the wrong claim ( left the solar system) rather than the claim the paper that science is publishing ACTUALLY makes ( entered interstellar space )

The two are not one and the same - very important distinction to make.

In terms of the number of objects orbiting our Sun - Voyager will be passing them by for another 300 years.

Posted by: TheAnt Sep 13 2013, 07:18 AM

Wonderful, even though those two items I posted in August did convince me, it did not take that long for the rest of the space science community jumped onto the bandwagon this time. =)

And djellison is right, news media is excused but a bit embarrassing to see AAAS stating V1 have left the solar system The Oort cometary region is still far ahead.

A NASA page has gone up now: http://www.jpl.nasa.gov/news/news.php?release=2013-277

Posted by: Explorer1 Sep 13 2013, 07:45 AM

Link already posted by me, Ant smile.gif

And yes, dates for leaving the solar system are certainly subjective. Ask a heliophysicist and they'll say this past year, a comet scientist will say several centuries from now, a planetary scientist will say 1988/9, and a mathematician will say never.
Go figure.... rolleyes.gif

Posted by: Paolo Sep 13 2013, 08:25 AM

QUOTE (TheAnt @ Sep 13 2013, 09:18 AM) *
And djellison is right, news media is excused but a bit embarrassing to see AAAS stating V1 have left the solar system The Oort cometary region is still far ahead.


on the other hand, from a dynamical point of view, Voyager is no longer bound to the Sun (since 1979 in fact), so it can be considered to have left the solar system

Posted by: djellison Sep 13 2013, 06:16 PM

QUOTE (Paolo @ Sep 13 2013, 12:25 AM) *
Voyager is no longer bound to the Sun (since 1979 in fact), so it can be considered to have left the solar system


So you're saying that New Horizons left the solar system as its third stage burned out, a few hundred miles above the Earth?

I don't think anyone would agree that's a fair assessment. Speed is not location. "Where are you?" "Mach 30"

Posted by: dilo Sep 13 2013, 06:40 PM

QUOTE (djellison @ Sep 13 2013, 07:16 PM) *
... Speed is not location. "Where are you?" "Mach 30"

Good point, Paolo/Doug! I always thought that space exploration lies in a six dimensions domain, a perfect mix of space and velocity or, better, distances and "delta-v". From this viewpoint, I think that you're both right!

Posted by: 0101Morpheus Sep 13 2013, 10:56 PM

Voyager finally made it! This is a historic moment, for real this time rolleyes.gif

OK but even if Voyager is currently drifting in interstellar plasma that does not change the fact that

1. Cosmic rays are still coming predominantly from one direction.

2. There has not been an significant field shift.

And Voyager 1 has about ten years of power to answer these questions. Plus who knows when Voyager 2 will enter the interstellar medium.

There is still a lot of work to be done here...

Posted by: djellison Sep 13 2013, 10:59 PM

Hopefully, as Voyager 2 has more instruments to bring to bear on the situation - it should help solve some of those problems.

Posted by: 0101Morpheus Sep 14 2013, 12:21 AM

Are there any estimates when Voyager 2 will cross the heliopause? Considering that now that we know Voyager 1 crossed it a year ago, the boundary was pretty close to the initial estimate.

Considering just how large the heliosphere is, ten years is not that much time. Even if Voyager is in the interstellar medium, it is still in a special region that is being effected by the heliosphere. And because we don't know how large this region is, it is possible that the voyager probes will be spending the rest of their lifetimes in it.

Posted by: TheAnt Sep 14 2013, 01:12 PM

As for V2 there's been some suggestions the solar wind & magnetosphere bubble might be lopsided. So it might take a while more, then again, the V1 passage came relatively suddenly without any clear sign beforehand. So the answer is that we simply do not know.
This all due to the fact that most ideas about this region have ended up being incorrect in the last year. (Though IBEX gave a hint some time earlier.)

Now that the solar wind at this distance is so ratified and the magnetic field correspondingly weak that the transition zone were undramatic and hardly noticeable except for the particle count that we payed attention to in Sept 2012 http://www.unmannedspaceflight.com/index.php?showtopic=1046&view=findpost&p=191390
The counter press release in post #104 might look a bit embarrassing for JPL, but it's actually a sign of good science where one is not only supposed to measure 'twice and cut once' but constantly re-measure as the cut is made to make sure everything is correct. smile.gif

Anyhow, you might be correct, Voyager1 might spend the rest of the mission in this region, my long term interest on this matter have had me keep an eye on Voyager and later on Ibex (even before it were launched) for exactly this. Er rather when someone publish a paper on these findings.
There's many things that other people get excited about on the net, in my case it's certain scientific papers. smile.gif

Posted by: Mongo Jul 9 2014, 02:09 AM

http://phys.org/news/2014-07-sun-tsunami-voyager.html

NASA's Voyager 1 spacecraft has experienced a new "tsunami wave" from the sun as it sails through interstellar space. Such waves are what led scientists to the conclusion, in the fall of 2013, that Voyager had indeed left our sun's bubble, entering a new frontier.

"Normally, interstellar space is like a quiet lake," said Ed Stone of the California Institute of Technology in Pasadena, California, the mission's project scientist since 1972. "But when our sun has a burst, it sends a shock wave outward that reaches Voyager about a year later. The wave causes the plasma surrounding the spacecraft to sing."

Data from this newest tsunami wave generated by our sun confirm that Voyager is in interstellar space—a region between the stars filled with a thin soup of charged particles, also known as plasma. The mission has not left the solar system—it has yet to reach a final halo of comets surrounding our sun—but it broke through the wind-blown bubble, or heliosphere, encasing our sun. Voyager is the farthest human-made probe from Earth, and the first to enter the vast sea between stars.

"All is not quiet around Voyager," said Don Gurnett of the University of Iowa, Iowa City, the principal investigator of the plasma wave instrument on Voyager, which collected the definitive evidence that Voyager 1 had left the sun's heliosphere. "We're excited to analyze these new data. So far, we can say that it confirms we are in interstellar space."

Our sun goes through periods of increased activity, where it explosively ejects material from its surface, flinging it outward. These events, called coronal mass ejections, generate shock, or pressure, waves. Three such waves have reached Voyager 1 since it entered interstellar space in 2012. The first was too small to be noticed when it occurred and was only discovered later, but the second was clearly registered by the spacecraft's cosmic ray instrument in March of 2013.

Cosmic rays are energetic charged particles that come from nearby stars in the Milky Way galaxy. The sun's shock waves push these particles around like buoys in a tsunami. Data from the cosmic ray instrument tell researchers that a shock wave from the sun has hit.

Meanwhile, another instrument on Voyager registers the shock waves, too. The plasma wave instrument can detect oscillations of the plasma electrons.

"The tsunami wave rings the plasma like a bell," said Stone. "While the plasma wave instrument lets us measure the frequency of this ringing, the cosmic ray instrument reveals what struck the bell—the shock wave from the sun."

This ringing of the plasma bell is what led to the key evidence showing Voyager had entered interstellar space. Because denser plasma oscillates faster, the team was able to figure out the density of the plasma. In 2013, thanks to the second tsunami wave, the team acquired evidence that Voyager had been flying for more than a year through plasma that was 40 times denser than measured before—a telltale indicator of interstellar space.

Why is it denser out there? The sun's winds blow a bubble around it, pushing out against denser matter from other stars.

Now, the team has new readings from a third wave from the sun, first registered in March of this year. These data show that the density of the plasma is similar to what was measured previously, confirming the spacecraft is in interstellar space. Thanks to our sun's rumblings, Voyager has the opportunity to listen to the singing of interstellar space—an otherwise silent place.

Posted by: MarcF Jul 24 2014, 02:26 PM

Is Voyager 1 Really in Interstellar Space? New Test Could Prove It for Good:
http://www.space.com/26628-voyager-1-interstellar-space-controversy.html?cmpid=514630_20140724_28353606
It seems that it is still not clear that V1 has indeed entered interstellar space !
Regards,
Marc.

Posted by: MarcF Dec 16 2014, 07:37 PM

Some news from our old friend:
http://www.jpl.nasa.gov/news/news.php?feature=4411

The "tsunami wave" that NASA's Voyager 1 spacecraft began experiencing earlier this year is still propagating outward, according to new results. It is the longest-lasting shock wave that researchers have seen in interstellar space.

"Most people would have thought the interstellar medium would have been smooth and quiet. But these shock waves seem to be more common than we thought," said Don Gurnett, professor of physics at the University of Iowa in Iowa City. Gurnett presented the new data Monday, Dec. 15 at the American Geophysical Union meeting in San Francisco.
...

Mysterious things happening outside the heliosphere. Can't wait to have Voyager 2 outside too.
Regards,
Marc.

Posted by: TheAnt Dec 24 2014, 09:25 PM

Agreed, with both Voyagers outside the heliosphere we could learn about the direction and speed of these events.

But the particle flux for Voy2 still not showing http://voyager.gsfc.nasa.gov/heliopause/v2la1.html the spacecraft might be approaching the border.

Posted by: TheAnt May 20 2015, 02:01 AM

Some quite dramatic swings in the >0,5 MeV data, together with an ever increasing trend toward the 2,3 particle per second in the >70 MeV particle data hits that something might be in the works for Voyager 2 also now.
Not saying that we're there yet, there were large swings on the graph before V1 eventually did enter interstellar space, and this does not look exactly the same either. So this is posted only a small heads up that something is happening after a quite long and unevenful timespan.

http://voyager.gsfc.nasa.gov/heliopause/GIF/v2la.12m.gif

Posted by: jgoldader May 21 2015, 01:34 AM

On the one hand, the V1 events were those "bottoming out" events right before breakthrough, but this is going up. On the other hand, I don't recall seeing such an abrupt jump in recent times. Gripping hand, maybe there's a high density pileup of particles caused by some shock front. I check every single day, can hardly wait... Hope she makes it through while she and I are both still functioning. laugh.gif

Jeff

Posted by: TheAnt May 22 2015, 11:19 AM

Yes you're correct Jeff that it was a series of dips in the graph before V1 went into the interstellar realm. So my description was a tad too conservative. tongue.gif Tthe rise in May really made me think of a shock front, and I wondered if the magnetic field lines have taken an abrupt turn to cause such an increase of particles.
If that is the case, and if V2 actually are at the boundary, I think we got a fair chance that both you, me and V2 will be fully functional to follow this. =)

Edit for adding the graph for the past year, this looks absolutely wild!
There's a pattern to this though, after each time the particle count have peaked, it falls back to a value that is about the same as the previous top value - we can see 2 times in this graph, though there's one more further back in time also.


Posted by: TheAnt Nov 1 2015, 06:12 PM


Sometime it take time for the analysis to appear. And that is the case for Voyager 1 passing the heliopause. But it might still be a whole decade before the spacecraft will be in true interstellar space. Data from IBEX have led the researchers to this conclusion.

A nice summary can be found at http://www.eurekalert.org/pub_releases/2015-10/uonh-uss102815.php

The count for 0,5 MeV ions by Voyager 2 have made a dip after reaching values never seen before in open space, this might indicate that it is close to the same boundary. Then again, the count for higher energy particles have actually been dropping, so we might have to wait for any of the pros to give an estimate of what actually is going on here.


Posted by: Mongo Nov 2 2015, 04:16 PM

http://www.centauri-dreams.org/?p=34338

QUOTE
Nathan Schwadron (University of New Hampshire) and colleagues have reanalyzed magnetic field data from Voyager 1, discovering that the direction of the magnetic field has been turning ever since the craft crossed into interstellar space. The work, published in Astrophysical Journal Letters confirms that the magnetic field direction at the center of the IBEX ‘ribbon’ is aligned with the magnetic field in the interstellar medium. Voyager is, in other words, now moving through a distorted region. By 2025, the magnetic field around it should align with the field direction found by IBEX.

At that point, we’ll be able to say that Voyager 1 has reached a more settled part of the interstellar medium, less perturbed by the ‘churn’ of the heliosphere. “This study provides very strong evidence that Voyager 1 is in a region where the magnetic field is being deflected by the solar wind,” says Schwadron in this JPL news release.

[...]

The paper is Schwadron et al., “Triangulation of the Interstellar Magnetic Field,” Astrophysical Journal Letters Vol. 813, No. 1, L20.


Abstract: Determining the direction of the local interstellar magnetic field (LISMF) is important for understanding the heliosphere's global structure, the properties of the interstellar medium, and the propagation of cosmic rays in the local galactic medium. Measurements of interstellar neutral atoms by Ulysses for He and by SOHO/SWAN for H provided some of the first observational insights into the LISMF direction. Because secondary neutral H is partially deflected by the interstellar flow in the outer heliosheath and this deflection is influenced by the LISMF, the relative deflection of H versus He provides a plane—the so-called B–V plane in which the LISMF direction should lie. Interstellar Boundary Explorer (IBEX) subsequently discovered a ribbon, the center of which is conjectured to be the LISMF direction. The most recent He velocity measurements from IBEX and those from Ulysses yield a B–V plane with uncertainty limits that contain the centers of the IBEX ribbon at 0.7–2.7 keV. The possibility that Voyager 1 has moved into the outer heliosheath now suggests that Voyager 1's direct observations provide another independent determination of the LISMF. We show that LISMF direction measured by Voyager 1 is >40° off from the IBEX ribbon center and the B–V plane. Taking into account the temporal gradient of the field direction measured by Voyager 1, we extrapolate to a field direction that passes directly through the IBEX ribbon center (0.7–2.7 keV) and the B–V plane, allowing us to triangulate the LISMF direction and estimate the gradient scale size of the magnetic field.

Posted by: Xcalibrator Sep 2 2017, 02:52 PM

For what it's worth, a paper just came out ("Time-varying Heliospheric Distance to the Heliopause", Washimi, Tanaka, and Zank, Astrophysical Journal Letters 846, L9, 2017 Sep 1) that predicts Voyager 2 should reach the heliopause any day now--you know, give or take a year. They use a model that includes the effects of global merged interaction regions, injecting one of typical size once per year, as well as the varying solar wind ram pressure, which varies over the solar cycle and which they model with a couple step functions. They don't compare with previous work so I'm not sure why this hasn't been done before or what the differences are, although they say that adding the GMIRs pushes out the heliopause by about 14 AU compared to a static model. They tuned their results by 4% to match the Voyager 1 heliopause encounter, but even so there's a fair amount of uncertainty because the model predicts that the heliopause will be moving outward for the next few years just as V2 is getting really close. V2 is moving faster, so it's steadily closing the gap, but from my reading there may be even more of the out?/in?/out shenanigans than V1 saw.

Edit: Voyager particle data https://voyager.gsfc.nasa.gov/data.html.

Posted by: Xcalibrator Sep 5 2018, 03:35 PM

Maaaaaybe something interesting is happening with Voyager 2. See plots https://vepo.gsfc.nasa.gov/Voyager_heliopause.html. 0.5 and 70 MeV particle fluxes tend to be correlated, but shortly before the V1 heliocliff they went in different directions. If this really is the precursor to breakout into the ISM, it should be clearer by next week. Plots are updated a couple times a week.


(The image above links to the regularly updated plot.)

Posted by: dtolman Sep 17 2018, 03:23 AM

As of a week later, I see its spiking a lot higher, then started dropping rapidly - for those of us following along at home - if this would follow the v1 plot, would this then crash to the floor?

Posted by: Xcalibrator Sep 17 2018, 03:22 PM

QUOTE (dtolman @ Sep 16 2018, 11:23 PM) *
As of a week later, I see its spiking a lot higher, then started dropping rapidly - for those of us following along at home - if this would follow the v1 plot, would this then crash to the floor?

dilo included a nice plot of the V1 data in http://www.unmannedspaceflight.com/index.php?showtopic=1046&view=findpost&p=195098 showing how the >0.5 MeV proton rate crashed to 2.1 and >70 MeV rose less dramatically to 2.26 ct/s. The latest modeling I've read about suggests that the boundary is (or was in 2017) moving outward while V2 is catching up to it. If the boundary breathes in and out, V2 may cross it more than once, making things a bit confusing. The web-page tools that let you make your own plots seem to have lost access to the latest data in the intervening years so we'll just have to wait for what they give us every few days. (Sorry, I can't figure out how to post dilo's plot directly here.)

Posted by: Xcalibrator Sep 22 2018, 02:23 AM

The https://voyager.gsfc.nasa.gov/data.html are continuing to look very promising, and they were updated not once but twice(!) today, after many months of couple-times-a-week. I'd bet the >0.5 MeV rate is below 10 ct/s by the end of next week and then we'll see it in the news.




Posted by: Xcalibrator Oct 8 2018, 02:10 PM

Well, I was too optimistic about the timing, but there is some attention in the http://spaceref.com/voyager/voyager-2-could-be-nearing-interstellar-space.html. Not really any new info there, but yes, we are officially getting close.

Edit: Note that although the plots say "6-Hour Avg" they are actually 12-hour aves. They switched several months ago (or maybe a year or two)--don't know why.

Posted by: Floyd Oct 8 2018, 05:27 PM

The >70 Me V just need to climb from 2.05 to 2.25 and the >0.5 Me V drop from 27 to about 2. Hoping by the end of the Month...


EDIT Nov 6, 2018 https://vepo.gsfc.nasa.gov/Voyager_heliopause.html to plots. Both plots are about to go off scale in the correct direction!!!

Posted by: Xcalibrator Nov 6 2018, 10:33 PM

There are some pretty big flux changes in the past two days. A watched high-energy particle detector never boils, but any day now...

Posted by: Floyd Nov 7 2018, 05:29 PM

It seems to be happening. Xcalibrator Plots above seem to update to latest plots automatically rather than display the plots for the day he posted (Sept 21). The November 7 Plot for >0.5 MeV has dropped to 20. I'll bet Xcalibrator's prediction of under 10 particles/second for >0.5 MeV occurs by November 11---OK it may take 3 week rather than one from Sep 21 for his prediction---but it really seems to be happening.

Edit 11/8/18 The >70MeV is now up to 2.25 (interstellar space level Voyager 1) and the >0.5 MeV down to 19 cts/sec. Moving nicely...Looks like we are in the Heliocliff. Still possible to get to 10 cts/sec by Monday smile.gif

Posted by: alan Nov 9 2018, 05:34 PM

NASA Voyager @NASAVoyager

Rumors of Voyager 2's exit from the heliosphere have been greatly exaggerated. Check out the y-axis on this graph. It goes down to 19. We're waiting for a count of near zero heliospheric particles/sec before she's joined me in interstellar space. https://go.nasa.gov/2JThxXq

https://twitter.com/NASAVoyager/status/1060720885345079296

Posted by: Floyd Nov 9 2018, 07:23 PM

The Voyager Twitter is to be believed over speculation in this thread. That said 2 cts/sec in the 0.5 MeV channel is the number we want to get down to (not zero). If you look at the necessary drops to get there we need to go from about 27 at end of October to 2 outside. In five steps that would be 27, 22, 17, 12, 7, 2. We went from 27 down to 19 (almost 2 steps) and have bounced up a bit today. So when we get below 17 we will be 2/5 of the way there. Five counts/sec drops are possible in 1-2 days, but getting under 7 and close to 2 could still be some time off. We will know a lot more by Monday on how fast and how monotonic this drop is. Are we in the Heliocliff? We will know when we hit 2 and/or the Voyager team makes an announcement.

Posted by: Xcalibrator Nov 9 2018, 09:16 PM

Let's see if I can show the Voyager1 plot from dilo/post86 here for more convenient comparison....

http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=29078

Posted by: Floyd Nov 10 2018, 01:48 PM

Thanks Xcalibrator, that is very helpful. I had not realized the >0.5 MeV had dropped from 25 to under 10 twice before finally bottoming out for Voyager 1. The fall is definitely not monotonic. Drop to about 17 on 10th. Back up to 19 on 11th. So we will bounce up and down for a while.....

Posted by: Floyd Nov 16 2018, 07:00 PM

Well we are definitely not down to 2 yet on the >0.5 MeV, but we have dropped from 26 to below 16 (as of 11/17/18) and are doing a lot of bouncing up and down. Hopefully Voyager 2 will exit the heliosphere and be down to 2 by 2019 rolleyes.gif I believe the image below will automatically update once or twice a day--check Generated Date and time at bottom. I believe time is Z and so -5 EST and -8 PST.


Posted by: Floyd Nov 18 2018, 06:07 PM

Nice drop to 11 counts/sec for >0.5 MeV/nuc ions today (11/18/18), but if Voyager 2 is like Voyager 1 we may bounce back up to 24-28 counts/sec a couple of times before exiting the heliosphere for real.

Edit 11/20/18. Down to 8 counts/sec for >0.5 MeV/nuc ions. Looking promising, but could bounce all the way back up. When it gets to 6 counts/sec I think we can safely conclude we are in the Helioclif. When it gets to under 4 counts/sec I think we can conclude there will be an announcement from the mission...


Edit 11/23/18 8:44am EST. Well no data posted 11/22 (Thanksgiving in US) and the chart generated and posted 11/23 05:10:06 2018 is the same as the chart posted on 11/21---so we are not seeing recent data points.

Posted by: Floyd Nov 23 2018, 06:49 PM

New data posted. Nice drop to 6 counts/sec for >0.5 MeV/nuc ions today (Fri Nov 23 6:10:24 2018). When we got this low on the >0.5 MeV/nuc ions and above 2.2 particles/sec on the >70 MeV/nuc ions on Voyager-1 we had exited the heliosphere (see http://www.unmannedspaceflight.com/index.php?showuser=6994 chart post #144 above). We could still bounce back up, but I doubt it. I think we might hear from the Voyager team very soon.



x

Posted by: Roby72 Nov 24 2018, 12:13 AM

How far out from the sun was Voyager 1 in 2012 at the egress of the heliosphere and how this distance compares now with the Voyager 2 egress ?
"DSN Now" tells 17.9 billion kilometers for Vgr2...but this is Earth to Spacecraft distance.
I think the heliosperic "bubble" will change in size over time and make some wobbles and is also different in the direction you leave (I don't think its a round ball)
Both Voyagers are leaving the solar system in pretty different directions.

Posted by: Floyd Nov 24 2018, 01:16 AM

Voyager 2 is about 144 AU from the sun currently. Voyager 1 crossed the heliopause in August 2012, then at a distance of 121 AU from the Sun. The shape of the heliosphere is definitely not spherical, and Voyager 2 is coming out at a place where the boundary is further from the sun than Voyager 1. There is more information at the https://voyager.jpl.nasa.gov. It took 1 year for NASA to officially report Voyager 1 entering interstellar space, because there was no precedent and no one really knew what it should look like. This is the second time, so an announcement should be a shorter than one year post exit. cool.gif

Edit: Thanks MarcF, I mixed up current Voyager distances from Sun in post above. Voyager 1 is 144 AU from the Sun currently and Voyager 2 is 119.18 AU. So Voyager 2 may be exiting about 2 AU closer to Sun than Voyager 1.

Posted by: MarcF Nov 24 2018, 11:32 AM

I think it is Voyager 1 that is currently about 144 AU from the sun.Voyager 2 is about 119 AU, which is close to the 121 AU exit distance from Voyager 1. So Voyager 2 is coming out at a place where the boundary is a little bit closer from the sun than Voyager 1, as was also the case for the terminal shock crossing.
Regards
Marc.

Posted by: Roby72 Nov 24 2018, 02:19 PM

Thanks Marc !
That's only 1.5% near the value of Vgr1 - the idea of a round bubble is not as wrong as I thought !

Posted by: Floyd Nov 24 2018, 06:28 PM

Thanks MarcF for pointing out my swapping Voyagers 1 & 2 current distances from Sun.

The >0.5 MeV/nuc ions particles/sec continues to drop to 5 today (11/24/18). Here are the figures again so they will be seen on this page of the thread.

Edit 11/26/18: Well reading have bounced up the past two days. Up from about 5 to 9 particles/sec in the >0.5 MeV/nuc ions. Hope counts don't bounce all the way back to 26, but we will see.





Posted by: Roby72 Nov 28 2018, 11:23 PM

QUOTE (MarcF @ Nov 24 2018, 12:32 PM) *
I think it is Voyager 1 that is currently about 144 AU from the sun.Voyager 2 is about 119 AU, which is close to the 121 AU exit distance from Voyager 1. So Voyager 2 is coming out at a place where the boundary is a little bit closer from the sun than Voyager 1, as was also the case for the terminal shock crossing.
Regards
Marc.

When we define the exit out of the solar bubble at around 121 AU to 119 AU then also Pioneer 10 should be already out of it now according to this distance calculator:
https://spaceoutreach.com/spaceflight/leaving-solar-system/
Pioneer 10 runs at about 122.3 AU now
But this spacecraft is silent since 16 years !

Posted by: MarcF Nov 29 2018, 01:24 PM

I like your link Roby72. It seems that Voyager 2 will soon catch up Pioneer 10. Pioneer 11 and the two Voyagers travel toward the sun apex direction, but Pioneer 10 takes the opposite direction. If the heliosphere has a bubble shape, Pioneer 10 could indeed have already crossed the heliopause. But if it has an elongated, comet-like shape as predicted by many models, Pioneer 10 would be very fare from leaving the influence of the solar wind.
Regards,
Marc.

Posted by: Floyd Nov 30 2018, 04:40 PM

Well the instrument readings are headed back down after a significant bump up. I was beginning to think Voyager 2 had second thoughts about leaving the Heliopause and had turned around to come back (momentum is not a problem if you can flip the time reversal switch).

We may bounce some more--or not...


Posted by: Floyd Dec 6 2018, 08:53 PM

Well, Voyager 2 is down to 3.5 particles/sec in the >0.5 MeV/nuc ions and up to 2.4 particles/sec in the >70 MeV/nuc ions. Outside the Heliopause Voyager 1 has had reading down in the 2-3 particles/sec in the >0.5 MeV/nuc ions and up to >2.2 particles/sec in the >70 MeV/nuc ions. SO VOYAGER 2 READINGS ARE AT VOYAGER 1 OUTSIDE THE HELIOPAUSE LEVEL. People may want to see current levels hold for a time before making an announcement, but I think we are within in one particle/sec in the >0.5 scale from being at Voyager 1 levels.

We are definitely in the Helioclif region


Posted by: MarcF Dec 10 2018, 01:24 PM

Okay, it's done, Voyager 2 is officially in the interstellar space smile.gif
https://www.jpl.nasa.gov/news/news.php?feature=7301

Regards
Marc.

Posted by: Xcalibrator Dec 10 2018, 04:40 PM

At the NASA/AGU press conf (11am EST) shown online, Ed Stone had a plot of the >70 MeV CRS particle flux with a V2 normalization factor of 1/1.08, so that the V2 interstellar flux (around 2.44) would match V1's 2.26 particle/s. Is there anyone at the AGU meeting who saw the conference talk who can comment on where that 1.08 came from? Is it just an empirical scaling so they match? I'd noticed the flux difference before and wondered if one might expect it because of real differences in particle density or velocity (or nonuniform velocity distribution if the detector orientation matters).

Posted by: Floyd Dec 10 2018, 06:17 PM

Congratulation to Dr. Stone and the entire team. It has been exciting watching the graphs as Voyager 2 exited over the past 6 weeks.

Posted by: cIclops Dec 11 2018, 11:44 AM

https://www.youtube.com/watch?v=kVJG1FhGeN0

Posted by: Xcalibrator Jul 15 2019, 03:12 PM

Both the Cosmic Ray Subsystem https://voyager.gsfc.nasa.gov/_recent/v2la1.html and https://voyager.gsfc.nasa.gov/_recent/v2pgh.html plots for V2 show stepwise drops in late June. The CRS is not directional, so it's not caused by any change in pointing. Could there be some other instrumental change, or does this indicate a real change in the plasma conditions (which would be really cool)?



 

Posted by: Xcalibrator Jul 31 2019, 05:29 PM

Ah, it was instrumental. They've now added "CRS Heater Off" labels to the plots around 2019.486.

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