http://mars.jpl.nasa.gov/odyssey/newsroom/.../20070327a.html

Engineers for NASA's Mars Odyssey mission are examining data from the orbiter to determine whether onboard backup systems never used by the 6-year-old spacecraft could still be available if needed.

Odyssey reported last week that a power processing component of the backup, or "B-side," systems had stopped working. The component, the high-efficiency power supply, has a twin that is continuing to serve the "A-side" hardware, which is operating normally. Odyssey has stayed on its A-side systems, including the A-side flight computer, since launch on April 7, 2001. However, the A-side power supply cannot serve most systems on the B-side, including the backup B-side computer. If engineers do not determine a way to restore the B-side power supply, most of the backup hardware would not be available, if it were ever needed.

Odyssey is in its second extended mission. The orbiter is conducting scientific observations and also serving as the primary communications relay for NASA's Mars rovers. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Odyssey Project for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft.


I hope Odyssey is not one failure away from another MGS-type loss because of this.

Sounds kind of ominous, all right. Surprised that such a critical component apparently doesn't have a fail-safe operational mode, or a separate backup unit; not enough internal redundancy? Come to that, why weren't the two power systems designed to allow crossfeeding?

I'm sure there are good answers to these questions just as sure as I am that I don't know anything about Odyssey's design.. ..and "Monday-morning quarterbacking" isn't the intent here. Very interested in the design attributes employed for fail-operational situations on spacecraft, though.

So this sounds like kind of good bad news - bad news that's not really too awfully bad. As I understand it, the primary systems are still just peachy, but the backups are getting flaky.
Hopefully they do figure this out though. Those folks at NASA and JPL seem to work remote miracles on their hardware. It's a testament of good engineering when a malfunctioning robot is still capable of not only keeping itself going (generally), but also transmitting diagnostics information back home. True they can't account for everything, otherwise MGS might still be going, but they can apparently deal with quite a bit. Spirit pulled through a pretty nasty problem early on. And heck, now Spirit's pulling a nasty problem along with for a ride - its right front wheel.

Odyssey Off-line Due to Glitch

http://news.yahoo.com/s/ap/20070918/ap_on_sc/mars_probes

Odyssey Returning to Service After Taking Precaution
http://www.jpl.nasa.gov/news/features.cfm?feature=1473

The spacecraft is expected to point its instruments and UHF relay antenna toward Mars today (Tuesday), to resume relaying communications from the Mars rovers on Wednesday.

> ... to resume relaying communications from the Mars rovers on Wednesday.

Today is Wednesday. The next UHF relay session is with Spirit at 12:06 UTC and the data should be downlinked at 15:55 UTC hitting the exploratorium web at 16:35.

Cross your fingers.

We just take Odyssey for granted.But it has issues at the moment.

Unexpected temperature rise in the star camera has delayed a system reboot.
http://www.nasa.gov/mission_pages/odyssey/...y-20090310.html

Related story on the reason for the reboot.
http://www.nasa.gov/mission_pages/odyssey/...y-20090304.html

Looks like the procedure went well and redundancy has been restored:

http://www.jpl.nasa.gov/news/news.cfm?release=2009-046

Kinda funny that after two years of worrying about the bad power supply the solution was to turn it off and back on again.

It's the "back on again" part that's worth two years of study before turning off something that's a couple of hundred million kms away, though. Well done, Odyssey team!

I am trying to locate the exact date in late 2003 when Odyssey's orbit was frozen to 5 PM equator crossing. Can anybody help?

I don't think that is correct. I believe it was February 19, 2002.

From Saunders, "2001 Mars Odyssey Mission Summary" (Space Science Reviews, 110, 2004, 1-36;


see also this image from the same paper:

According to marsprogram.jpl.nasa.gov, Odyssey went into safe mode on july 14. The reason - an encoder controlling a gimbal that moves the solar array didn't perform correctly. A redundant encoder was switched in and the gimbal itself performed well. Full opps should resume this week. YAAAY!!

Brian

Odyssey is back online after switching to a spare reaction wheel. Hang in there!

http://news.yahoo.com/mars-odyssey-spacecr...-155336794.html

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.

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.

Thanks! It's good to be here.



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.



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

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.

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.

Doug,


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.


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.

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.

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?




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.

Measuring fuel levels on spacecraft is a problem common to all. New topic to talk about it here.

....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' ?

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.

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

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...



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...)

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.

Odyssey uses ring laser gyros. From http://research.nianet.org/~rtolson/docume..._MRO_AB_JSR.pdf



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

Ah silly me. I made the mistake of looking in Tolson's paper on Odyssey to find out about Odyssey's IMU.... of course, the info is in a paper on MRO.....


Interesting !
Thanks

Noted in passing: the 11th anniversary of Odyssey's active mission passed a few weeks ago in February, and the 12th (!) anniversary of its launch is a couple of weeks from now, on April 7.

We don't know how much longer it can last, but it's certainly had a good run.


Doug M.