Voyager Enters Final Frontier Of Solar System Options

[Guest_Sunspot_*]

http://planetary.org/news/2005/voyager-upd...ation_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.

[Guest_spaceffm_*]

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

[djellison]

Is Voyager still this functionial?

No, basically

Doug

[edstrick]

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.

[Guest_PhilCo126_*]

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

[ljk4-1]

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

[The Messenger]

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?

[deglr6328]

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

[mike]

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)..

[ljk4-1]

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

[Rob Pinnegar]

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.

[ljk4-1]

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.

[ljk4-1]

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/

[ljk4-1]

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

[dilo]

From updated solar wind speed diagram, 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 ions density spikes ever observed by the spacecraft...
Any suggestion?

[Rem31]

From updated solar wind speed diagram, 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 ions density 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.

[Rob Pinnegar]

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.

[dilo]

Something is definitely happening around Voyager-2!
Last nucleon data shows that, after 10 months of caothic behavior, density dropped to very low levels; in the meantime, wind speed 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!

[dilo]

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

[Bob Shaw]

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

[Guest_Myran_*]

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.

[ljk4-1]

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 .

[climber]

[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.

[dilo]

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!

[ljk4-1]

Voyager 2 Detects Odd Shape of Solar System's Edge

http://www.space.com/scienceastronomy/0605...here_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.

[climber]

[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.

[Guest_PhilCo126_*]

The greatest traveller of all times !

[Guest_Analyst_*]

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

Analyst

[SigurRosFan]

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

Yes, it should happens on August 17, 2006!

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

[ljk4-1]

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_...lar_System.html

[ljk4-1]

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/solars...er_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)

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.ntr..._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

[ljk4-1]

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

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

[MCS]

There's a new story 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.

[dilo]

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/voyag...plot_recent.gif
(in the past, I was looking more often to these data but in recent months I'm more and more busy ).
Looking to this Forum section, it seems nobody noticed it... cannot believe anyone missed it like me!

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

[dilo]

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 this 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!

[scalbers]

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.

[brellis]

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

The solar system is 'dented' as reported in this CNN Article.

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 this post over in the New Horizons thread.

thank you dmuller!)

[Paolo]

In the latest issue of Astronomy & Astrophysics
Imaging the heliosheath using HSTOF energetic neutral atoms and Voyager 1 ion data

[Fran Ontanaya]

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

http://web.mit.edu/afs/athena/org/s/space/...yager_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.

[Guest_PhilCo126_*]

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

[Paolo]

The latest issue of Astronomy & Astrophystics (v491 n1) has some articles about heliospheric science, including results from Voyager, Ulysses, Cassini, Nozomi etc.

[dilo]

Grazie, Paolo. Very interesting!

[Guest_Enceladus75_*]

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?

[Fran Ontanaya]

About lifetime:

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

[dilo]

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.

[Guest_Enceladus75_*]

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.

[dilo]

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!

[Barnard]

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?

[remcook]

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

[ZLD]

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

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

[brellis]

From the 12/14 Space Daily article (wait - that's tomorrow! hehe)

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?

[ZLD]

I think this article could help:
http://www.sciencedaily.com/releases/2009/...91016142056.htm

Also:
http://www.sciencedaily.com/releases/2009/...91016101807.htm

[g4ayu]

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

[rogelio]

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-04...0,4527527.story

[jasedm]

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

[mchan]

A Big Surprise from the Edge of the Solar System

Intriguing "frothy magnetic bubbles".

[MarcF]

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/ful...s.2011.370.html

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

Best regards,
Marc.

[jgoldader]

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

[remcook]

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

[Paolo]

today on Science express: Voyager Measurements of Hydrogen Lyman-α Diffuse Emission from the Milky Way

[remcook]

Great, still doing good science!

[JTN]

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 online supplement.)

Measurements are said to be taken with the ultraviolet spectrometer (UVS). This page 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.

This page (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?

New Scientist says the instruments have since been turned off (corroborated by this page: V1 1998, V2 2002).

[stevesliva]

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

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

From the supplement:

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.

[Paolo]

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 online supplement.)

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.

[MarcF]

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.

[hendric]

It's getting really exiting

Best UMSF Freudian slip ever.

[MarcF]

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

[volcanopele]

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

[ups]

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

[MarcF]

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

[dilo]

Ever closer...

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

extracted from here:
 v1_1d_08_on_8ion.pdf ( 106.9K ) Number of downloads: 785

[MarcF]

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

[dilo]

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/vg...d_avg_09_on.pdf

[Astro0]

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

Sail on lil' Voyagers! Sail on!

[RoverDriver]

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

[Paolo]

on the next issue of Nature
Voyager’s long goodbye
No meridional plasma flow in the heliosheath transition region
the latter requires a subscription

[jasedm]

I think that Voyagers are the coolest mission.

Paolo

Seconded.

[dilo]

I think this combined plot speaks by itself:

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

[TheAnt]

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 'The little motor that could'

[dilo]

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

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

[EdTruthan]

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. MORE HERE

[Floyd]

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

[Hungry4info]

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

[Floyd]

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.

[djellison]

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.

[dilo]

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!

[Explorer1]

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

Nothing at the usual NASA link....

[Tesheiner]

News release: NASA Voyager 1 Encounters New Region in Deep Space.

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.
...

[0101Morpheus]

So much for there being a clear cutoff point

[djellison]

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

[Explorer1]

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'.

[djellison]

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

[0101Morpheus]

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.

[Explorer1]

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.

[0101Morpheus]

Seems we got our replies mixed up.

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.

[TheAnt]

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.
Voyager 2 data page

[djellison]

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.

[Explorer1]

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.

[stevesliva]

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.)

[TheAnt]

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. =)