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Odyssey mission status
Doug M.
post Aug 8 2012, 08:17 PM
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Hello all,

New member, first post. I have a few questions about Odyssey, and I'm hoping some of the well-informed members here will have answers!

1) What mission extension is Odyssey on? As far as I can tell, it had a fourth extension from 2010 to 2012. It should be on the fifth extension now, I suppose? Does anyone know if it is; and if so, until when does it run?

2) What's the current fuel supply? About when is it expected to run out?

3) Is fuel likely to be the limiting factor for Odyssey's lifespan?

4) What's the current status of Odyssey's various instruments? I know that MARIE (Mars Radiation Environment) has been dead since 2003, and another instrument has been inoperative. Is THEMIS the only instrument now operating?

5) I know that Odyssey is acting as a relay for MSL, of course. But I'm not up to speed on the details -- like, how often; how important is Odyssey's contribution; is it UHF only; how much can Odyssey buffer; things like that. (I am not asking anyone to sit down and write all that out! A link would be fine, if there's a page or paper somewhere explaining it.)

Many thanks in advance,


Doug M.
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Tom Tamlyn
post Aug 9 2012, 12:27 AM
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Doug M., welcome to the forum.

Those are interesting questions, but did you do any google searches of your own before you posted your wish list?

Googling "mars odyssey fourth mission extension," I found a mission timeline maintained by dmuller indicating that the third mission extension ended in September 2010. Refining the search to add the term "2010," I found a Universe Today article by Ken Kremer (mars loon) that answers most of your questions.

It would be a good idea to read the Rule and Guidelines for umsf.com.

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Doug M.
post Aug 9 2012, 07:25 AM
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QUOTE (Tom Tamlyn @ Aug 9 2012, 01:27 AM) *
Doug M., welcome to the forum.


Thanks! It's good to be here.

QUOTE
Those are interesting questions, but did you do any google searches of your own before you posted your wish list?


Yes, I did. A brief one, I admit, but I did. I found the Universe Today article -- it's a reference on Odyssey's wikipedia page.

QUOTE
Googling "mars odyssey fourth mission extension," I found a mission timeline maintained by dmuller indicating that the third mission extension ended in September 2010. Refining the search to add the term "2010," I found a Universe Today article by Ken Kremer (mars loon) that answers most of your questions.


The Muller timeline is not terribly helpful -- it's a brief listing of past events, and it gives a "predicted fuel exhaustion" of 2015, which is not consistent with other sources.

The Universe Today article is much better. However, it's two years old, and doesn't really answer my questions. For instance, it states that “More than 95 percent of the data from Spirit and Opportunity and approximately 79 percent of the data from Phoenix was relayed by Odyssey.” That's interesting, but it doesn't tell us anything about Odyssey's relationship with Curiosity. With regard to the fuel issue, the article says that “21.6 kg of propellant remains with an average consumption rate of about 1.4 kg per year... [however,] there are other elements of the spacecraft that might suggest that Odyssey’s life expectancy could be closer to six years. Lifetime issues are extremely difficult to estimate." That's some solid information, which is great. However, it doesn't tell us what the status is now, two years later. Has the fuel consumption stayed constant? Did the flywheel episode cost any fuel? Odyssey had to perform an unprecedented roll maneuver to gain signal from Curiosity; did that increase fuel consumption? Looking forward will the demands of communicating with two rovers require regular attitude changes; and if so, can this be done by flywheel, or will Odyssey have to burn more fuel?

It's entirely possible that this information is out there, and I'm just not googling hard enough! But to answer your question, yes I have made at least a basic online search; I wouldn't bring these questions here if I hadn't at least tried to find the answers first myself.

many thanks,


Doug
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stevesliva
post Aug 9 2012, 04:47 PM
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QUOTE (Doug M. @ Aug 9 2012, 02:25 AM) *
With regard to the fuel issue, the article says that “21.6 kg of propellant remains with an average consumption rate of about 1.4 kg per year... [however,] there are other elements of the spacecraft that might suggest that Odyssey’s life expectancy could be closer to six years. Lifetime issues are extremely difficult to estimate." That's some solid information, which is great. However, it doesn't tell us what the status is now, two years later. Has the fuel consumption stayed constant? Did the flywheel episode cost any fuel?


I read those lines with the same sort of thoughts as you-- they're pretty prescient. Perhaps they had something in mind like the reaction wheels when they said fuel might not be the limiting factor. And if Odyssey is like Mars Express, the safe mode certainly costs fuel.

Also, I was surprised with some googling how difficult it is to locate more mundane mission status reports for Odyssey, mostly because most of the search results are mirrors of the bigger NASA press releases. But they also might not really exist. Because it does sound like only THEMIS is working, perhaps meaning status reports would be rather useless without an anomaly. And the issue with the anomaly reports is that they're rather terse because they offer little rope for someone to hang them with.
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elakdawalla
post Aug 9 2012, 06:09 PM
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The reason such things aren't online is because a mission in its kajillionth extension has almost no budget left; they're running on a shoestring, with probably the majority of their funding focused on keeping it around for communications with landers. I'm surprised they're still doing image of the day releases. The best way to get answers to these questions would be to send a polite, brief and to the point email to the NASA public information officer whose name and email address appears on Odyssey press releases, and tell them you plan to post any answers here. It's that person's job to get questions answered that aren't already answered online.


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Tom Tamlyn
post Aug 9 2012, 07:45 PM
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Doug,

QUOTE
The Universe Today article is much better. However, it's two years old, and doesn't really answer my questions.

It does address some. For instance, since the fourth mission extension runs through September 2012, it's pretty clear that we're not yet "on the fifth extension now." I agree that it's a little surprising and frustrating that what would seem to be a simple housekeeping question about the mission status isn't readily available. The absence of a formal press release announcing approval of a fifth extension may be due to the shoestring issue mentioned by Emily upthread; it may also be due to the fact NASA's fiscal year 2013 budget currently appears to be pending before Congress.

OTOH, there doesn't seem to any reason to think that Odyssey is going to be shut down on October 1. If you're really interested in the budgetary and bureaucratic minutiae documenting the hand-off from the fourth extension to the fifth extension, it would be etiquette to show that you've dug into the budget and planning materials available from the NASA portal before asking for help. Also, note that one of the forum's strongest policies is ixnay on oliticspay.

A June 2012 press release indicates that gamma ray spectrometer is still functioning, although it doesn't discuss whether both of the instruments in the grs suite described as functioning in the Universe Today article are still OK.

QUOTE
The Universe Today article ... doesn't tell us anything about Odyssey's relationship with Curiosity.

Right. The MSL landing press kit, which is featured in the MSL FAQs and USEFUL DOCUMENTS thread in this the MSL forum, provides some basic information about Curiosity's telecom link with Odyssey and MRO, along with lots of other detailed information (it's a really useful basic resource). There's also a link to an exceptionally detailed discussion of the MSL's telecommunications system design.
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Doug M.
post Aug 10 2012, 10:09 AM
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Emily, that's a great idea. Checking the press releases, I see that there are indeed a couple of names given, with accompanying e-mail addresses.

However -- these guys are probably a little distracted just now. I would expect that any NASA PIO with a connection to Mars has a pretty full plate right now. So I may wait a bit, until the first wave of excitement over MSL has calmed down a bit.


Doug M.
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Doug M.
post Aug 10 2012, 10:34 AM
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QUOTE (Tom Tamlyn @ Aug 9 2012, 09:45 PM) *
I agree that it's a little surprising and frustrating that what would seem to be a simple housekeeping question about the mission status isn't readily available. The absence of a formal press release announcing approval of a fifth extension may be due to the shoestring issue mentioned by Emily upthread; it may also be due to the fact NASA's fiscal year 2013 budget currently appears to be pending before Congress.

OTOH, there doesn't seem to any reason to think that Odyssey is going to be shut down on October 1. If you're really interested in the budgetary and bureaucratic minutiae documenting the hand-off from the fourth extension to the fifth extension, it would be etiquette to show that you've dug into the budget and planning materials available from the NASA portal before asking for help. Also, note that one of the forum's strongest policies is ixnay on oliticspay.


I've read the forum guidelines, so I'm aware of the ban on politics. And it strikes me as a very good idea, having seen plenty of interesting discussions get threadjacked in other forums.

I actually did several searches, using terms like "Odyssey extension", "Odyssey fifth extension", "Mars Odyssey 2012 budget", and the like. This has turned up some interesting stuff, like the MEPAG assessment of the next decade of NASA's Mars architecture, but no details on Odyssey.

I realize that as a new poster, I have no track record here. Possibly making my first post a string of questions was a mistake! If so, my bad. But going forward, it seems like it would be a bit tedious to preface every question with a description of failed search efforts. Would a simple statement that "I've tried looking for this, but have been unable to find it" suffice?


QUOTE
The MSL landing press kit, which is featured in the MSL FAQs and USEFUL DOCUMENTS thread in this the MSL forum, provides some basic information about Curiosity's telecom link with Odyssey and MRO, along with lots of other detailed information (it's a really useful basic resource). There's also a link to an exceptionally detailed discussion of the MSL's telecommunications system design.


The MSL press kit is indeed a great resource, and one of which I was unaware. Thank you!

The detailed discussion you mention: I assume this is the Descanso article. Clicking through to that, I find on page iii that it's #14 of a series of articles... and that article #6 in the series was"Odyssey Telecommunications" byAndre Makovsky, Andrea Barbieri, and Ramona Tung! Ah ha. And sure enough, here it is. It's a 2002 article that of course does not mention Curiosity -- but it's darn interesting reading anyhow. (And it shows that NASA was anticipating multiple Mars surface missions well over a decade ago, and designed Odyssey's comm capabilities accordingly.)

Thanks again for your helpful response,


Doug M.

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nprev
post Sep 7 2012, 06:36 PM
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Measuring fuel levels on spacecraft is a problem common to all. New topic to talk about it here.


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rlorenz
post Nov 17 2012, 03:13 PM
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QUOTE (stevesliva @ Aug 9 2012, 11:47 AM) *
I read those lines with the same sort of thoughts as you-- they're pretty prescient. Perhaps they had something in mind like the reaction wheels when they said fuel might not be the limiting factor.



....and sure enough, the 11/12/2012 status report at http://mars.jpl.nasa.gov/odyssey/ says they've just swapped to the B-side electronics string. I note the release says 'side swap was initiated last week in response to months of diagnostic data indicating that the A side's inertial measurement unit shows signs of wearing out. This gyroscope-containing mechanism senses changes in the spacecraft's orientation'... so it's the gyros rather than wheels this time.

There's a long history of (mechanical) gyros being the life-limiting element, especially on astronomy missions. But I thought current Mars spacecraft used IMUs with ring laser gyros (or maybe FOGs). Unless this is a sloppy release Odyssey must have been the last Mars mission to use mechanical gyros, or can RLGs/FOGs actually 'wear out' ?
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Doug M.
post Nov 17 2012, 04:49 PM
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QUOTE (rlorenz @ Nov 17 2012, 05:13 PM) *
There's a long history of (mechanical) gyros being the life-limiting element, especially on astronomy missions. But I thought current Mars spacecraft used IMUs with ring laser gyros (or maybe FOGs). Unless this is a sloppy release Odyssey must have been the last Mars mission to use mechanical gyros, or can RLGs/FOGs actually 'wear out' ?


Brief googling suggests that it's mechanical gyroscopes. Definitely doesn't seem to be a ring laser. Mars Odyssey was designed an built in the late 1990s, so that would make sense.

Mars Odyssey has been in space for eleven and a half years now, and orbiting Mars for over a decade. It's currently the third oldest continually active science mission, exceeded only by the two Voyagers. So, not really a surprise that various systems are starting to show signs of age. Hopefully it will last long enough for the next orbiter (MAVEN, fingers crossed) to come along.


Doug M.
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djellison
post Nov 17 2012, 05:32 PM
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QUOTE (Doug M. @ Nov 17 2012, 08:49 AM) *
It's currently the third oldest continually active science mission, exceeded only by the two Voyagers.


I'm not sure by what measure you're making that claim...but of all the following launched earlier and are still working and doing great science.
Cassini, Acrimsat, ACE, Cluster, SOHO, WIND, Geotail, Terra, Landsat 7, Chandra, Hubble, XMM-Newton, TRMM
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rlorenz
post Nov 18 2012, 04:37 AM
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QUOTE (Doug M. @ Nov 17 2012, 11:49 AM) *
Brief googling suggests that it's mechanical gyroscopes. Definitely doesn't seem to be a ring laser. Mars Odyssey was designed an built in the late 1990s, so that would make sense.


Did you find anything definitive ?
Ariane launchers were using RLGs in the early 1990s, if not before AFAIK, so it isnt a given that just because it was designed in the 1990s it had to use mechanical gyros...

QUOTE
Mars Odyssey has been in space for eleven and a half years now, and orbiting Mars for over a decade....... So, not really a surprise that various systems are starting to show signs of age.


I believe the MERs used Litton LN-200 IMU's, which have fiber optic gyros. But the datasheet for those says MTBF of >20,000 hrs, which means failures after a decade are certainly not ruled out (though that could just be a lower limit from lot testing, rather than
actual experience showing that failures occur after a mean period of 21,000hrs...)
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Doug M.
post Nov 18 2012, 05:27 AM
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QUOTE (djellison @ Nov 17 2012, 07:32 PM) *
I'm not sure by what measure you're making that claim...but of all the following launched earlier and are still working and doing great science.
Cassini, Acrimsat, ACE, Cluster, SOHO, WIND, Geotail, Terra, Landsat 7, Chandra, Hubble, XMM-Newton, TRMM


Sorry, my bad. I meant outside Earth orbit! That would knock out all the above except Cassini and SOHO. Cassini wasn't doing active science for most of its cruise period, so it would lose on the "continually active". That leaves SOHO, which I eliminated because of the mission interruption. However, doublechecking, I find that the mission interruption was in 1998-1999, not in 2001-2 as I'd thought for some reason. So, fair enough -- SOHO is third, Odyssey is first. (And I had no idea TRRM was that old. Huh.)


Doug M.
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mcaplinger
post Nov 18 2012, 07:19 AM
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Odyssey uses ring laser gyros. From http://research.nianet.org/~rtolson/docume..._MRO_AB_JSR.pdf

QUOTE
Although the IMUs used on MRO were the same as ODY (QA-2000 accelerometers and GG1320 Ring Laser Gyros)...


Ring laser gyro lifetime limits are typically due to gas impurity buildups in the RLG cavity.


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