ESA Rosetta, news, updates and discussion Options

[paxdan]

Well Rosetta isn't going to get to 67P/Churyumov-Gerasimenko (Chury) till 2014, but it's not to early to set up a thread. There are a bunch of earth fly-bys, a Mars encounter at 200km in 2007 and a few asteriod passes. Not to mention the mission to land on the comet itself.

Only another nine and a half years to go.

[Guest_spaceffm_*]

Wow, i did not know that there will be a Mars Flyby.
Interesting...

[Guest_Sunspot_*]

Also, I believe they will be observing Comet Tempel 1 during the Deep Impact encounter.

[centsworth_II]

Wow, i did not know that there will be a Mars Flyby.
Interesting...

Rosetta will be able to add to the information on Mars methane/formaldehyde, according to this abstract (pdf file).

http://www.cosis.net/abstracts/EGU05/04196/EGU05-J-04196.pdf
The Mars flyby of Rosetta: an opportunity for atmospheric sounding
"It will be able to search for other minor species (CH4, H2CO...) and to study possible local variations..."

[paxdan]

Here is a nice self-portrait of the back of one of rosetta's solar pannels taken by one of the 6 micro cameras on the Philae lander. Looks like the pictures of the surface from the lander are gonna be sweet.

[DEChengst]

For those that understand German this site has lots of info about the Rosetta mission:

http://www.bernd-leitenberger.de/rosetta.html
http://www.bernd-leitenberger.de/philae.html

[Decepticon]

A few asteroid passes!

Great news. Wonder which ones???

Well Rosetta isn't going to get to 67P/Churyumov-Gerasimenko (Chury) till 2014, but it's not to early to set up a thread. There are a bunch of earth fly-bys, a Mars encounter at 200km in 2007 and a few asteriod passes. Not to mention the mission to land on the comet itself.

Only another nine and a half years to go.

[paxdan]

During the first earth flyby by Rosetta which took place on the 4th of March, ESA ran a competition to find the best ground based images of the spacecraft during closest approach. The winners were announced on Monday. A gallery of all images taken of the spacecraft is available here.

I remember reading that due to the large size of rosetta's solar panels there was the hope that the shape of the spacecraft migh be resolvable, alas, only one submitter claims to have resolved some structure.

Rosetta meanwhile took some excellent photos of the earth and moon during the encounter

[cIclops]

Here is a nice self-portrait of the back of one of rosetta's solar pannels taken by one of the 6 micro cameras on the Philae lander. Looks like the pictures of the surface from the lander are gonna be sweet.

OMG it's full of stars ...

[paxdan]

A few asteroid passes!

Great news. Wonder which ones???

This website gives details of two asteriod flybys:

5 sept 2008 - flyby at asteroid 2867 Steins
10 july 2010 - flyby at asteroid 21 Lutetia

NOTE: I've updated this post to include the hyperlinks given in the article for the asteroid biogs.

This post has been edited by paxdan: Apr 22 2005, 12:26 AM

[imran]

And I thought the seven years that Cassini took to get to Saturn was long. I don't know what I will doing 9 and a half years from now. It is definitely going to be worth the wait. The pictures look really sharp!

[Guest_Sunspot_*]

http://www.esa.int/SPECIALS/Rosetta/SEMT4V2IU7E_0.html

ESA’s comet chaser mission Rosetta took these infrared and visible images of Earth and the Moon, during the Earth fly-by of 4/5 March 2005 while on its way to Comet 67P/Churyumov-Gerasimenko.

[Decepticon]

A repeat of above data from TPS. http://planetary.org/news/2005/rosetta_ear...mages_0506.html

[Guest_BruceMoomaw_*]

Good news on the problem with the sticky thermal door covering the OSIRIS cameras -- a problem which ESA had indicated in two status reports starting in January, but about which I simply could not pry any information from them. (Even Mike A'Hearn -- who is a co-investigator! -- had only been told that it was "some kind of stickiness".) ESA's close-mouthedness is a serious pain in the ass.

However, judging from the latest status report, they seem to have finally developed a software fix for it (after one unsuccessful earlier try).

http://sci.esa.int/science-e/www/object/in...fobjectid=37534 :

"On 31 May a test of the OSIRIS door mechanism was carried out with the
presence of the PI team at ESOC. The purpose of this test was to
characterise the behaviour of the flight model, compare it with the test
results on the ground models and finalise the new software routines for the
control of the door to be uplinked on 14 June. The test was successful and
the OSIRIS team has already delivered the new software. ESOC is preparing
for next week's uplink and verification operations."

[Guest_BruceMoomaw_*]

Postscript: they do plan to use the OSIRIS cameras -- along with all of Rosetta's other remote-sensing instruments -- to observe Tempel 1 during the Deep Impact collision.

[djellison]

Bruce - would you classify ESA's press efforts as almost being obstructive in places?

Doug

[Guest_BruceMoomaw_*]

I don't know if "obstructive" is the word, but "idiotic and counterproductive" are definitely applicable. I just stumbled across an old clipping from the JBIS on why the ESA chose to initially display the photos from Giotto in that way that made them totally incomprehensible (and infuriated Thatcher to the point that she forbade Britain to get involved in any major way with the ESA): they were DELIBERATELY made incomprehensible to the public so that the camera's principal investigator would have absolutely total control over their initial interpretation!

I don't know how much of this is the inevitable tangle that accompany international cooperation, and how much is due to the phenomenon in which Jeffrey Bell firmly believes: that European nations still have distinctly anti-democratic and pro-aristocratic tendencies in their political leadership and so still try to resort to "Father Knows Best" approaches in dealing with their own citizens. If so, they've just received another rude awakening on that front...

[djellison]

I swear I saw some fantastic nebulae observations by one of the Rosetta instruments somewhere online at one point.

Buggered if I can find them now

Is there any sort of public-group that represents the public to Nasa? I'm not aware of one, but a representative body that say "right - you need to tell us about x, y, and z, and stop wasting money on b and c" or something? (nasawatch doesnt count )

I think something seriously needs to be done to sort ESA out. I wanted to find some HRSC images a few days ago, and it took me for ever to find that page that just has them all listed, it's ..well...crap.

The interface for HRSC data is worse than crap as well.

The Marsis thing is a case in point. We should have had a blog type thing, something, ANYTHING to keep us up to date, I figure there's about £1 of my money invested in MEX, so it's time for some pay back

Doug

[ljk4-1]

ROSETTA STATUS REPORT

Report for Period 9 December 2005 - 6 January 2006

The reporting period covers four weeks of passive cruise, with
monitoring and minor maintenance activities.

On the subsystems side, the attitude guidance has been changed to +X
Earth pointing on 14 December 2005, to reduce the disturbance torques
experienced by the spacecraft and therefore the fuel consumption for
reaction wheel offloading.

http://sci.esa.int/jump.cfm?oid=38558

[SigurRosFan]

http://fr.arxiv.org/abs/astro-ph/0602631 - First albedo determination of 2867 Steins, target of the Rosetta mission

--- On the basis of its polarimetric slope value, we have derived an albedo of 0.45 +/-0.1, that gives an estimated diameter of 4.6 km, assuming an absolute V ma gnitude of 13.18 mag. ---

[Guest_BruceMoomaw_*]

Thre's some speculation that Steins may be one of the rare E-type asteroids (enstatite chondrite) -- although it's so small that its near-IR spectrum is rather fuzzy.

[edstrick]

The unusually high albedo measured with both polarimietry and with brightness + thermal infrared data (we need Spitzer measurements) really does seem to put this rock in the "e" category. I don't know how sure they currently are that this corresponds to rare and "weird" Enstatite chondrites. Is it the enstatite chondrites that have nearly identical oxygen isotope systematics to Earth and Moon rocks?

ANY opportunity to get a good look as something besides variations-on-a-theme of S type asteroids is extremely welcome. The only totally limited look we have of one is NEAR's nice flyby sequence of C type Mathilde, but it's just a nice sequence of pictures, mostly.

The short 6-hour rotation rate of Steins will help get some rotational coverage, like Gaspra and Ida.

[ugordan]

What exactly will the closest approach distance to 2867 Steins be? I'll settle for an order-of-magnitude number if the distance is not precisely known yet.

[paxdan]

What exactly will the closest approach distance to 2867 Steins be? I'll settle for an order-of-magnitude number if the distance is not precisely known yet.

Flyby September 5, 2008, at 1700 kilometres.

[Bob Shaw]

And earlier still:

February 2007 - Rosetta Mars flyby (200km altitude)

Bob Shaw

[ugordan]

February 2007 - Rosetta Mars flyby (200km altitude)

It wonder if they have any plans to produce a flyby movie similar to the one MESSENGER's team produced during the Earth flyby.
It would be cool to see Mars rotate and disappear in the distance, possibly with Phobos and Deimos dancing around it.

[Bob Shaw]

It wonder if they have any plans to produce a flyby movie similar to the one MESSENGER's team produced during the Earth flyby.
It would be cool to see Mars rotate and disappear in the distance, possibly with Phobos and Deimos dancing around it.

The ESA website simply says 'some science observations' will be carried out. Anyone know more?

Bob Shaw

[Guest_BruceMoomaw_*]

They definitely intend to use the MIRO microwave spectrometer during the Mars flyby -- the first time such an instrument has ever been used there -- to make Martian atmospheric observations. (Such a gadget would have been added to MRO if they'd had the weight margin for it). I believe they also intend to use many of the other instruments, too -- although most of them would just reiterate the far more sweeping orbital observations that Mars Express has been doing.

[JTN]

Since I've just done the sums, I thought I'd share:
(Quite) approximate pixel size of the asteroids in OSIRIS NAC (2048 x 2048 pixels @ 0.00115 deg/pix) at closest approach:
2867 Šteins: 4.6km @ 1700km => 135 pixels
21 Lutetia: 95.8km @ 3000km => 1600 pixels

[ljk4-1]

Astrophysics, abstract
astro-ph/0603585

From: S. Alan Stern [view email]

Date: Tue, 21 Mar 2006 19:04:41 GMT (508kb)

Alice: The Rosetta Ultraviolet Imaging Spectrograph

Authors: S.A. Stern, D.C. Slater, J. Scherrer, J. Stone, M. Versteeg, M.F. A'Hearn, J.L. Bertaux, P.D. Feldman, M.C. Festou, J.Wm. Parker, O.H.W. Siegmund

Comments: 11 pages, 7 figures

We describe the design, performance and scientific objectives of the NASA-funded ALICE instrument aboard the ESA Rosetta asteroid flyby/comet rendezvous mission. ALICE is a lightweight, low-power, and low-cost imaging spectrograph optimized for cometary far-ultraviolet (FUV) spectroscopy. It will be the first UV spectrograph to study a comet at close range. It is designed to obtain spatially-resolved spectra of Rosetta mission targets in the 700-2050 A spectral band with a spectral resolution between 8 A and 12 A for extended sources that fill its ~0.05 deg x 6.0 deg field-of-view. ALICE employs an off-axis telescope feeding a 0.15-m normal incidence Rowland circle spectrograph with a concave holographic reflection grating. The imaging microchannel plate detector utilizes dual solar-blind opaque photocathodes (KBr and CsI) and employs a 2 D delay-line readout array. The instrument is controlled by an internal microprocessor.

During the prime Rosetta mission, ALICE will characterize comet 67P/Churyumov-Gerasimenko's coma, its nucleus, and the nucleus/coma coupling; during cruise to the comet, ALICE will make observations of the mission's two asteroid flyby targets and of Mars, its moons, and of Earth's moon.

ALICE has already successfully completed the in-flight commissioning phase and is operating normally in flight. It has been characterized in flight with stellar flux calibrations, observations of the Moon during the first Earth fly-by, and observations of comet Linear T7 in 2004 and comet 9P/Tempel 1 during the 2005 Deep Impact comet-collision observing campaign

http://arxiv.org/abs/astro-ph/0603585

[GravityWaves]

And earlier still:

February 2007 - Rosetta Mars flyby (200km altitude)

Bob Shaw

I've heard nothing on this Mars flyby where does ESA release its press info ?

[Rakhir]

I've heard nothing on this Mars flyby where does ESA release its press info ?

Rosetta journey : http://www.esa.int/SPECIALS/Rosetta/ESA38F7708D_0.html
Rosetta factsheet : http://www.esa.int/esaSC/SEMJ09374OD_0_spk.html
Geometry of the flyby : http://www.space.irfu.se/rosetta/sci/mars/

[ljk4-1]

Astrophysics, abstract
astro-ph/0603720

From: Jessica Agarwal [view email]

Date: Mon, 27 Mar 2006 13:00:59 GMT (713kb)

Imaging the Dust Trail and Neckline of 67P/Churyumov-Gerasimenko

Authors: J. Agarwal (1), H. Boehnhardt (2), E. Gruen (1 and 3) ((1) MPI-K Heidelberg, (2) MPS Katlenburg-Lindau, (3) HIGP Honolulu)

Comments: 4 pages, 3 figures, to be published in the proceedings book of the conference "Dust in Planetary Systems 2005"

We report on the results of nearly 10 hours of integration of the dust trail and neckline of comet 67P/Churyumov-Gerasimenko (67P henceforth) using the Wide Field Imager at the ESO/MPG 2.2m telescope in La Silla. The data was obtained in April 2004 when the comet was at a heliocentric distance of 4.7 AU outbound. 67P is the target of the Rosetta spacecraft of the European Space Agency. Studying the trail and neckline can contribute to the quantification of mm-sized dust grains released by the comet. We describe the data reduction and derive lower limits for the surface brightness. In the processed image, the angular separation of trail and neckline is resolved. We do not detect a coma of small, recently emitted grains.

http://arxiv.org/abs/astro-ph/0603720

[Rakhir]

A busy period for Rosetta :
- Honda comet tail observation last July
- Lutetia observation in January (At very far distance I guess. Does anyone know the distance ?)
- Mars flyby in February
- Jupiter observation in April in support of New Horizon

http://sci.esa.int/science-e/www/object/in...fobjectid=40366

[tedstryk]

A busy period for Rosetta :
- Honda comet tail observation last July
- Lutetia observation in January (At very far distance I guess. Does anyone know the distance ?)
- Mars flyby in February
- Jupiter observation in April in support of New Horizon

http://sci.esa.int/science-e/www/object/in...fobjectid=40366

I am not sure, but I wonder if we can improve on this shape model. This looks to be a battered relic.

[elakdawalla]

- Lutetia observation in January (At very far distance I guess. Does anyone know the distance ?)

This doesn't give an exact distance but it looks pretty far. Rosetta is currently interior to Mars in its orbit, so it looks like it's around 1 AU away.

From http://neo.jpl.nasa.gov/cgi-bin/db?name=21

Attached thumbnail(s)

 

[IM4]

>Lutetia observation in January (At very far distance I guess. Does anyone know the distance ?)
approximately 1.62 AU at January 1, 2007 and increasing up to 1.8 AU by the end of the month.

Quite strange moment for imaging, Rosetta will have tens of "encounters" within 0.1 AU while going through inner parts of Main belt after 2007-2008. Of course , it will be rather small asteroids, smaller than giant Lutetia (almost 100 km long), but yet suitable targets for exporation.

[Rakhir]

Quite strange moment for imaging, Rosetta will have tens of "encounters" within 0.1 AU while going through inner parts of Main belt after 2007-2008.

Rosetta will meet Lutetia again on 10 July 2010 for a close flyby (from a distance of 3000 km).

[mchan]

Rosetta will meet Lutetia again on 10 July 2010 for a close flyby (from a distance of 3000 km).

Something to look forward to. The largest asteroid to be encountered to date, and an M-type asteroid which has not been seen close up before. Now if only the ESA folks will kindly post raw images as they receive them...

[Holder of the Tw...]

Does anyone know whether it will be possible to do a mass determination during the Lutetia flyby? Usually these require ultra stable oscillators attached to the transmitters, in order to get a stable enough frequency to track the doppler shift. And you would like to fly as close to your target as possible.

Seeing as how it's an M type, a density measurement, even if it's rough but reasonable (spec. grav +/- 1.5), would be a very useful piece of information.

[edstrick]

a 3000 km flyby is pretty useless for any asteroid mass determination unless the 'oid is something really big, like over 100 km. What's Lutetia's est. diam?

[mchan]

Around 100 km. So it's borderline.

[ugordan]

Well, Galileo flybys of Gaspra and Ida were around the same ballpark distance (1600 and 2400 km, respectively) and mass estimates were acquired, probably through two-way doppler before and after the encounter. Rosetta is reaction wheel controlled so in principle it should allow a rough mass estimate to be given in the same way, especially since Lutetia is significantly more massive than the former two so its signature should be much more easily detectable.

EDIT: On second thought, determining Ida's mass was much more straightforward. It has a moon orbiting at a known distance and a known orbital period so mass can be determined to high accuracy. As for Gaspra, the following page has this to say:

Most asteroids are too small to produce noticeable effects on spacecraft. Galileo's 1991 encounter with the asteroid Gaspra produced only images. In 1993, however, Galileo is scheduled to fly by the asteroid Ida, and it is expected that the relatively close approach to Ida will yield the first experimentally measured estimate of an asteroid's mass and therefore density. The corresponding constraints on its composition will allow new insight into theories of the evolution of the solar system and asteroid belt.

[Rakhir]

Rosetta warms up for Mars swing-by
http://www.esa.int/esaCP/SEMNJ8D4VUE_index_0.html

Instruments from both Rosetta orbiter and Philae lander will be used during the observation campaign.
The purpose of the 36-hour observation campaign of 21-Lutetia is to understand the rotation direction of the asteroid.

Rosetta will be able to observe Mars from about 20 hours before it makes its closest approach to about a few weeks after.
Rosetta instruments will be switched off around the eclipse period. However, Philae lander will still be operating and taking measurements during the eclipse as the lander has its own independent power system.

[mchan]

The ESA Rosetta website has a list of the various planetary and asteroid flyby's and their dates, but I did not find a graphic / plot of the trajectory. Is there a figure of the trajectory on ESA (or another public) website that shows the flyby's similar to the figure on the Messenger website for the Messenger mission --

http://messenger.jhuapl.edu/the_mission/trajectory.html

[Guest_AlexBlackwell_*]

For those interested in this kind of thing, a special issue of Space Science Reviews is in the works that will publish several Rosetta-related papers, mostly dealing with the instruments. Several of these papers are in press (i.e., "Online First"), and, for a limited time, SpringerLink is offering free access for non-subscribers, though one may have to register (freely).

Also, note that a paper on the James Webb Space Telescope was just published, and I believe access is free to this one as well.

[stevesliva]

I saw a passing mention of Phobos and Deimos observations... will these improve visual imagery/catrography, or does Rosetta have some new instruments to bring to bear... or both?

[ustrax]

I saw a passing mention of Phobos and Deimos observations... will these improve visual imagery/catrography, or does Rosetta have some new instruments to bring to bear... or both?

Here's everything Rosetta's has to give...

[IM4]

The ESA Rosetta website has a list of the various planetary and asteroid flyby's and their dates, but I did not find a graphic / plot of the trajectory. Is there a figure of the trajectory on ESA (or another public) website that shows the flyby's similar to the figure on the Messenger website for the Messenger mission --
http://messenger.jhuapl.edu/the_mission/trajectory.html

I recommend you download this file (3 Mb). It is mostly about planned plasma science but also contains a pair of schematic graphics like those I’ve attached to the message. On the image you can see Mars, orbits of Phobos (red), Deimos (green), estimated orbits of Mars Express (black), MGS (cyan), Mars Odyssey (yellow) and of course Rosetta trajectory (blue) - the spacecraft will approach Mars from the dayside (from the right) and make a swingby on the opposite side of Mars. There are also several useful figures and groundtrack in the file, so I can derive approximate timeline and summarize it as follows :

24 Feb. 2007 07.48 UT – flyby phase begins
25 Feb. 2007 01.00 UT – close approach to Mars begins
- 01.30-01.43 UT - Rosetta flies over Arabia Terra (h>3000 km)
- 01.45-01.50 UT – Rosetta crosses Chryse Planitia (2000>h>500 km)
- 01.55 UT – closest approach over Tempe Terra ~ 300E, 45N (h=250 km)
- 01.56 UT – Rosetta enters Mars shadow
- 02.05 UT – Rosetta flies over Olympus Mons (h=3000 km)
- 02.20 UT – Rosetta leaves Mars shadow (h=10000 km)
25 Feb. 2007 20.03 UT – flyby phase ends

It’s a real pity that significant part of the closest flyby happens in the nightside. Visual imaging will be possible only at greater distance and with moderate resolution, but I still hope that VIRTIS’s IR –cam can capture magnificent photo of martian plains [fixed:)] and mountains throughout the entire flyby. Another instruments are also expected to obtain interesting results.

Attached thumbnail(s)

 

[ugordan]

magnificent photo of martian planes

Don't let H0ag1and hear you! Thanks for the doc, btw.

[mchan]

IM4,

Thanks for the doc.

[Rakhir]

Lutetia asteroid in Rosetta’s spotlight

An animated sequence of Lutetia imaging and an image of Mars and the Milky Way taken by OSIRIS.

[elakdawalla]

I can't get RealPlayer or Windows Media Player to play the high-res version of the animation. Is anyone else having more success?

I wish ESA would post these things in a format that I could more easily repost. I know that animated GIF isn't the world's best animation format but it's something that I can pull individual frames out of and resize for posting...

That Mars and Milky Way image is really gorgeous, though!

--Emily

[nprev]

I can't get it to work, either, Emily; must be the site itself.

Agree with you, though: beautiful pics! Almost tempted to infer that the dark spot on Mars is Syrtis Major, but in all probability it's just an artifact.

[ustrax]

Emily,

you have to download the DivX viewer in order to see it.

EDITED: ...And the asteroid's details are quite remarkable...

[ustrax]

Another instruments are also expected to obtain interesting results.

One of the things I'm expecting with greater curiosity is the use of instruments from the Philae lander on Mars observations, it could give us some hints on what it could retrieve from the surface of the comet...

[Guest_AlexBlackwell_*]

Ongoing Preparations for Mars Swing-by
29 Jan 2007 09:29
Report for Period 13 January to 26 January 2007

[yaohua2000]

Rosetta will be soon exactly 10,000,000 miles away from Mars at 2007-Feb-04 05:26:33 UTC.

The spacecraft is currently going almost directly toward Mars with a speed of about 20560 mph.

[ugordan]

So, what is a more significant figure: 10,000,000 miles or 10,000,000 km?

[djellison]

What's a mile?

(well - it's a European spacecraft after all )


Doug

[ugordan]

A mile is in the eye of the beholder

Statute, nautical, imperial... yadayadayada...

[nprev]

I'm all for the metric system. If I could convince the USAF Reserve to let me run 2 km instead of 2 miles for my biannual physical fitness test, life would be better...

[centsworth_II]

The great thing about using a variety of units: miles, km, sols, days, etc.
is there are so many more milestones to celebrate. The more the merrier!

[NMRguy]

What's a mile?

(well - it's a European spacecraft after all )
Doug

Gee, Doug. I thought you British were just as good as us Americans for knowing how far a mile is on the road! (Even though you put the signs on the “wrong” side of the road.) You holding out on us?

[djellison]

If the UK would switch to KM, I'd be very happy.

Doug

[tedstryk]

I'll admit, I am a stick in the mud when it comes to metric...for space exploration, great, but as for every day life, give me miles, feet, pounds, and inches. Well, off to watch the game...

[dilo]

Ted, why to complicate your life using Km in space and Miles on Earth?
I have impression that the only way to convince all to use the same unit system is... to create a new one!
I know, is a madness... anyway, what do you think of the space covered by light in a billionth of sec? (hey, you should like it, is pretty close to a foot!). Then use all power of 10 units (metric is better from this standpoint, no doubt).
Even better, we could divide the day in 10^5 "seconds" and we will have such a lenght unit equal to 259mm or about 10 inch)... ok, stop the metric madness!

[ngunn]

If the UK would switch to KM, I'd be very happy.

Doug

Fine. Just don't interfere with the pint.

[djellison]

Wouldn't you rather have a litre

Doug

[ngunn]

Even that's not strictly SI. I'll have a cubic metre and a pork pie please.

[djellison]

I'm reminded of a rather foul song I co-wrote for a laugh whilst a teenager...I'll share it with you next time I see you - not suitable for forum consumption

John the Grocers life fell through the ground,
When he got nicked for selling apples by the pound.....

Doug

[tedstryk]

Wouldn't you rather have a litre

Doug

We have some things in liters. Mainly softdrinks.

[ugordan]

We have some things in liters.

So you're not even consistent?

[djellison]

Basically, in the 1970s, there was an abortive attempt to make America metric, but a few things did change and have stayed. My understanding is that something similar happened in the UK, but got a lot farther. I know the whole Celsius thing has been a point of confusion when I am on that side of the puddle (which collectively over the course of my life would total up to about a year), because, well, 40 degrees instinctively sounds cold to me, even though I know that it isn't on the Celsius scale.

[dvandorn]

As an American, I never got to see these "in person," but I saw one on a news story here. You see, when Britain went over to a decimal money system, they ran a series of public service announcements urging people to use the new decimal money.

The PSAs had a little jingle that I still recall, perhaps because of the actual way they stated some things. Specifically, while the decimal money was called decimal, the old-style money-counting system was referred to by the abbreviations for pound, shilling and pence, which for some odd (and I'm sure quite English) reason was abbreviated to "LSD." So you got:

"Decimal shops
Give decimal change,
LSD shops give...
LSD change!"

Hearing that for the first time, I figured there was no problem -- you'd have no issue getting rid of LSD change. Just invite a lot of people from San Francisco...

-the other Doug

[tty]

I can't understand why people would want to go metric, after all what's wrong with the old (Imperial?) system:

12 lines to an inch, 12 inches to a foot, 3 feet to a yard, 220 yards to a furlong, 8 furlongs to a mile and 3 miles to a league.

16 drams to an ounce, 16 ounces to a pound, 14 pounds to a stone, 2 stones to a quarter, 4 quarters to a hundredweight and 20 hundredweight to a long ton.


Now that is what I call creative units, and if it leads to an occasional case of unintentional lithobraking, so what.

[Greg Hullender]

Don't forget troy ounces. That's what makes the joke about "which weighs more, a pound of gold or a pound of feathers" work. (Answer: a pound of feathers weighs more, because a pound (avoirdupois) of feathers is 453 grams but a pound (troy) of gold is only 373 grams.)

--Greg

[helvick]

The part that I find really odd is that "Imperial" measures are fundamentally defined by calling on metric SI base units e.g. the international avoirdupois pound is defined officially as being equal to exactly 453.59237 SI grams. This opens up a whole other argument about pounds being units of force and not mass but I really don't think we should go there again.

In any case surely shouldn't the Pound be defined as equal to the weight of one of George Washington's boots or something?

[nprev]

Well, one of my latest classes is a crash physics review rolled into new stuff for space sensors, and all I can say is thank God for the metric system. I have enough trouble figuring out where to put decimal points without worrying about duodecimal/hex unit conversions to boot!!!

[dvandorn]

In any case surely shouldn't the Pound be defined as equal to the weight of one of George Washington's boots or something?

Actually, the yard used to be the distance between a liege lord's nose and the tip of his finger on an outstretched arm. No matter that a particular lord's lands had a different length for the yard than anyone else -- it placed his stamp on everything built during his reign.

-the other Doug

[ustrax]

Precious...Just precious...

"For detailed information regarding Rosetta's Mars Swing-by, please consult the Trajectory Status Presentation given by Trevor Morley from the ESOC Flight Dynamics Team for the Mars Swing-by Preparation Readiness Meeting that took place on the February the 2nd and which was kindly made accessible to spacEurope by Dr. Gerhard Schwehm."

[climber]

Isn't it ironic that all this "discution" about metric vs imperial occurs in the Rosetta's topic ?
M.Champollion, where are you?

[Greg Hullender]

I think it's because the switch to the metric system is almost the latest news we have from over there.

--Greg ;-)

[Guest_AlexBlackwell_*]

Rosetta correctly lined up for critical Mars swingby
ESA
15 February 2007

As an aside, several Rosetta instruments and investigations-related papers have been posted over the past few weeks in the "Online First" section of the journal Space Science Reviews. These papers will be assigned to a specific issue(s) at a later date.

[GravityWaves]

Here's everything Rosetta's has to give...

Looks like a great craft but what makes the Rossetta lander so different to the stunt the Japanese tried to pull with Itokawa

[djellison]

Minerva wasn't much of a scientist - camera, temp data and the ability to 'bounce' itself around a little.

Philae - however...

Rosetta Lander Scientific Instruments

Investigation of comet materials COSAC MPAe D chemical analysis with mass spectrometer (MS) and gas chromatograph (GC); pressure sensor Ptolemy Open University UK isotope analysis (ion trap, GC) APX MPCh D element analysis ( Alpha Xray Spectrometer) Cameras for viewing of the comet core ÇIVA IAS F panorama, stereo and microscope cameras, imaging infrared spectrometer ROLIS DLR D landing and down looking camera Investigation of comet core structure SESAME DLR D seismic measurements, dust monitoring, permittivity probing CONSERT CEPHAG/LPG F microwave tomography MUPUS Univ. Münster D penetrator with thermal sensors Plasma and magnetic environment ROMAP Univ. Braunschweig D magnetic field and plasma monitoring Sample Retrieval SD2 Politecnico di Milano I drilling and sample distribution

[edstrick]

"Philae - however..."

The entire Rosetta mission is entirely comparable to Galileo/Jupiter Probe, and Cassini/Huygens and in older times, Viking Orbiters and Landers in ambitiousness and in the scientific scope and variety of instruments. This is one big, impressive mission.

[mchan]

Indeed. I think of it as CRAF+. Kudos to ESA for stepping up with an enhanced mission after NASA had its budget slashed and had to renege on some of its international commitments.

[Guest_Analyst_*]

Correct. This is a flagship. It will give us much more return than Deep Impact, Contour and Stardust combined.

Not to discount the samples from Stardust or the possibility to study 3 different comets with Contour. But long term study is the key. To see the change, not to take snapshots. Using a suite of instruments. You can repeat observations to answer new questions. This is something Contour or Deep Impact could not do. Deep Impact in particular has been a big disappointment. For me it looked more like an engineering demonstration than a science mission. Stardust is a little bit different: There you have the material and can study it again and again. But these very short flybys should be something of the past (This is even true for New Horizons, but hey, there is no way to orbit Pluto, so you must flyby).

If I look at Discovery missions so far, many did carry only very limited instruments: MPF, Stardust, Contour, Deep Impact. On the other hand, orbiters were much more productive: NEAR, Lunar Prospector, hopefully Messenger and Dawn (although Dawns instruments are very limited too). Genesis is a little bit different, but Kepler has a very limited scope too.

I go as far and say: One flagship like Cassini (3 billion $) gives you much more return than 8 Discovery missions (400 million $ each). Discovery missions need a very large amount of their budget just to built the spacecraft bus and launch it. The science instruments are only tiny fraction. This relationship get better the bigger the mission.

Analyst

[djellison]

But of course, one LV failure with 8 discovery missions is a little less drastic than a single LV failure on a flagship mission. There are benefits to spreading things out a little.

Doug

[ngunn]

I've been thinking about this issue in relation to possible future outer solar system missions, possibly with major inter-agency collaborations. One possibility would be to launch component modules separately and assemble them in Earth orbit. You could have a single interplanetary propulsion unit plus entirely independent modules for (for example) planet orbiter, moon orbiter, balloon probes module, lander - the failure of any one of which would not jeopardise the entire mission. Of course it would be desirable to have a back-up interplanetary propulsion unit on the ground that the other bits could just wait in orbit for if necessary.

[centsworth_II]

There are benefits to spreading things out a little.

Also, multiple missions can be sent to multiple targets.

[Guest_Analyst_*]

All this considered, I stand by my opinion. Maybe the risks are higher (all eggs in one basket), but the benefits are higher too. For me, subjective, the benefits of flagship missions outweight the risks of loosing one.

Analyst

[tedstryk]

All this considered, I stand by my opinion. Maybe the risks are higher (all eggs in one basket), but the benefits are higher too. For me, subjective, the benefits of flagship missions outweight the risks of loosing one.

Analyst

To me, it depends. If funding levels are too low, and thus flagships get to rare and then one fails, the powers that be might get too used to not having planetary missions. Also, smaller missions are often needed to pathfind, in some cases to prove technology, and in others to do some basic reconnaissance to select instruments for a flagship.

In addition, it depends on the target. For the moon, or even Mars, a series of little missions works OK, at least for orbiters. But when it comes to the outer solar system, the cost of getting there makes small missions harder to justify, post Pioneer.

[elakdawalla]

I just thought I'd point out something I mentioned in the blog yesterday: The Society is sending your very own Doug Ellison to Darmstadt, Germany to cover the Mars flyby for the blog, since I can't travel for business right now. Be nice and give him some (virtual) company as he stares blearily at his laptop screen beginning around 2 am CET on Sunday...

--Emily

[ngunn]

I noticed that in your blog and was duly delighted. He will have plenty of company!

[SFJCody]

Is a long extended mission a possibility for Rosetta?

http://neo.jpl.nasa.gov/cgi-bin/db_shm?sst...p;search=Search

seems to indicate that the target comet will make a distant Jupiter pass around 2017/2018

[ustrax]

OSIRIS update.

[Stu]

Thanks ustrax... look at the last paragraph... "No timetable for publication" of the acquired data.

... sigh ...

[tedstryk]

Did he say anything about the trajectory for the upcoming earth flyby (or does anybody know?) I have long wished another spacecraft would make a Galileo-like flyby with its cameras on.