Maybe they don't want people to know what they're doing

Well - I found http://mgsw3.jpl.nasa.gov/seq/ which includes lots of similar info just by googling for "UHF Relay" - I can't believe that JPL would unintentionally allow that information to be out and about and so easy to find - indeed some parts are marked as being removed due to ITAR......but then it wouldn't be the first time that JPL would have let something be online that shouldn't have been. It wouldn't be beyond belief to have JPL stop updates going to that site because they didn't want people ( i.e. me ) reading it.

Doug

Just out of curiosity, what is MGS' consumable status? Reason I ask is that I hope it isn't burning fuel trying to reacquire Earth if that turns out not to be the appropriate course of action.

http://www.unmannedspaceflight.com/lofiver...x.php/t902.html

"As of 05-153 (06/02/05) MGS fuel consumption is 3.3 g/day, with 9.15 kg of usable fuel remaining. At this consumption rate, the usable fuel will support operations into 2013."


Doug

Much better than I'd hoped....thanks, Doug!

Lets not forget that this craft managed aerobraking with a busted wing, this bird is tough and the team backing her is the best.

Thanks very much for this site. I am usually hanging out at NASAspaceflight.com arguing about the VSE but when I heard about MGS having having problems I was very happy to find this site. For some reason MGS has always been one of my favorite birds, courage in the face of adversity or something I guess. I am drinking coffee out of my authentic JPL MGS mug and thinking good thoughts.

Unfortunately this is in the normal mapping attitude. In nearly all safe mode orientations it won't apply, and in some safe modes, it uses thruster control instead of reaction wheel control and will consume fuel even faster. But we are still talking fairly low consumption rates; it's not like it's spinning wildly about looking for Earth. Its normal response to faults is to get the solar arrays pointed at the sun and then spin slowly about the sun line, awaiting commands. There are a few complicating factors: first, the whole problem started with a stuck solar array (one of two); second, the spacecraft goes into solar and Earth eclipse on every orbit; and third, the low-gain transmitter antennas are both up on the articulated HGA electronics box, so there are some orientations of the HGA that could block one or the other of the LGTs from view from Earth. The low-gain receivers are down on the body of the spacecraft and do not articulate.

Compiled from public sources: see http://pds-geosciences.wustl.edu/missions/...og/insthost.txt and http://klabs.org/richcontent/Reports/Failu...erver_11_93.pdf

Hmm...okay, thanks very much for the elucidation, M.

Is it possible that the array is stuck in such a fashion that it's interfering with the HGA in between eclipse periods? I assume that MGS maintains inertial lock with respect to Mars nadir duing normal ops. If this scenario was true, then we might catch a break in a week or two due to the relative orbital motion between Earth & Mars (maybe longer...I think that we're in the middle of that long, slow distant "catch-up" phase between the two orbits).

With an array stuck I think MGS would immediately leave the nadir-fixed orientation, since the array would be unable to track the sun, as it would need to do. Unfortunately I don't know too much about the safing mode that is entered with a stuck SA gimbal; for example, what pointing of the HGA is commanded in that mode.
(Most of what I know is left over from Mars Observer, and the HGA never got deployed on that mission.)

I see. That sounds like a potentially much more serious situation, then; hopefully, it's entirely notional.

Well - reading the logs for MODY and MRO - I think they've turned off the updates to the webpage as they have no radiated files since before the last MGS log entry

Doug

Still no contact yet

http://space.newscientist.com/article/dn10...rs-orbiter.html

Late on Wednesday, MRO will try to determine MGS's location by taking a picture with a low resolution camera. Using this information, MRO will take another image of MGS on Friday using its High Resolution Imaging Experiment (HiRISE) – the most powerful camera ever sent to Mars.

The HiRISE image should be detailed enough to determine how MGS is oriented in space and how its solar arrays are positioned.

Whoa! Now there's a powerful means of hopefully resolving the problem...the pics should eliminate many possible failure modes. Thanks for the update, Sunspot.

Typical. Frakking typical!

For years we've been getting sensational pictures from Mars Global Surveyor, breathtaking images of martian features, dust-storms, the whole planet itself. We've seen gullies, craters, valleys and gorges in more detail than ever before. The probe just reached its tenth anniversary, an amazing achievement...

All that with hardly a nod of the head from the BBC.

But now, following the usual "bad news from space is the only news worth covering" guidelines, this morning, Kate Silverton - bless her cute, punky hair, elfin face and trendy square framed glasses... okay, I'm a fan... - is telling everyone on Breakfast TV about the "ailing probe", trotting out the usual "lost in space" cliches.

Not happy.

MGS images Odyssey
Digital data puts Mars on Map
Mapping Mars
Its Springtime on Mars
MGS enters Phase 2
Glitch forces mars probe shut off 2005
Shadow of a Martian Moon
Image may be polar lander
Evening Clouds on a Martian Volcano
Mars more active than thought
Mars May be Changing
Earth as seen from Mars by MGS

I could go on, however, just one more link Exploring Mars: In depth

What's wrong with a bit of coverage from the beeb at what may be EOM?

You are overreacting. BBCis one of the few news agencies that give quite frequent updates about planetary missions on their web front page.

Borek

In the article above, they plan to try to activate MGS UHF transmitter, listen for the carrier from the MERs and relay the results thanks to Mars Odyssey.
But what prevents listening the MGS carrier directly from Mars Odyssey ?
Incompatible frequencies or orbits ?

I am not over-reacting Borek. I was talking about TV coverage, probably should have clarified that (but come on, it was 6.30am!! ) Re-read my post please, I didn't mention websites. The web coverage is usually excellent, and I probably should have mentioned that. My bad. But we all know that TV cverage does tend to descend, vulture-like, on bad news stories.

If they do manage to recover it, I doubt it will make the news at all.

Calm down boys....calm down.


Anyway - back to the actual topic in hand...

Odyssey or MRO to MGS UHF comms - I've not thought of that but it should be possible - however I imagine that the signal strength pattern from the UHF antenna would require a serious spacecraft manouver for it to work.

Doug

Very interesting idea. But first you have to turn on the UHF receiver on MGS (including MOC). And you can do this via X-band only (I assume UHF and all instruments are off in safe mode.). I wonder if you can get commands to MGS via UHF from Odyssey or MRO. But why do this if you can command via X-band? So you need X-band commanding first, and if you have X-band commanding you don't need UHF (Except maybe to save power?).

Analyst

The thinking behind it is probably like this :

We are sending X-Band signals, but we do not know if it is getting them as we see no evidence in return

Most likely option - the vehicle is incapacitated and/or not recieving the signals.
Less likely - the vehicle is recieving them but for some reason can not transmit on X-Band

In the second case - if we uplink a command to transmit on UHF which Spirit/Opportunity might hear, then we will have evidence of life onboard MGS.

Basically, you start at the top of the fault tree and cross out all the different failure options until you've crossed them all out....at which point you go out, have a drink, toast MGS, and then move on.

Anyone who followed the MPL post-landing story will have been through this...it's painful, as you get to the increasingly unlikely failure modes, but on which you end up pinning more and more of your hopes.

Doug

Using the UHF, is it to try and send something from the rovers to MGS and then try and relay via Odyssey or use the rovers to try and listen in to see if the MGS is transmitting anything via UHF and then relay the results via Odyssey?

I read an article that mentioned it this morning but can's see it now

Edit: Ah, never mind

No - we'd have to use the DSN to command MGS to turn on it's UHF transmitter during a rover flyover...and then the rovers would report back to see if it worked....I MAY be wrong but I don't believe that MGS can be commanded via UHF.

Also - Stanford might get out their UHF antenna and see if a UHF carrier from MGS can be seen here on the ground....sometimes it gets a signal from Mars Orbiters, sometimes it doesn't.

Doug

Sadly not very likely , but this makes sense.

I followed MPL on CNN, all the press conferences, MGA pointing problems, sky scanning nada nada nada.

Analyst

Let me just pipe in and say from what I've been able to understand, the space.com article is the far more likely approach to what will happen. http://www.space.com/missionlaunches/061114_mgs_mro.html . It seems to cover the main concerns better than the other articles posted by other news sources.

....that was excruciating. I never want to go through that again.

Yeah, like with Beagle...

It's so easy to take orbiters for granted, but it really shows what a knife edge dance it is to keep power and communications and camera orientation all working without a hitch.

On an quasi-unrelated note, I wonder how much it would cost to build some redundancy into the DSN. Every blue moon, there seems to be some mission-impacting loss of communication - either a mouse has chewed through a cable, or a space probe goes on the fritz during the comm window for another mission, etc... it almost seems like an achillies heel that one day could really cause a major loss of data. Maybe it's time to build some extra nodes, like in Iceland and/or south Argentina or something?

Oh, that was a horrible, dragging, endless, check-Ceefax-and-websites-every-five-minutes Christmas Day.... ((shudders at the memory))...

Or maybe it's just time the DSN got the investment it deserves to install multiple 70m assets at each station, or the arrays of mass produced 12m dishes suggested at IAC.
http://www.iac-paper.org/abstractcd/2006/a...-06-B3.1.03.pdf



Doug

See also my notes from the Bob Preston talk at last May's OPAG meeting:
http://www.planetary.org/blog/article/00000570/

Upgrading infrastructure isn't a sexy project, but deep space communications really do represent a bottleneck, and the lack of upgrades to the DSN is harming our ability to make the most of our deep space assets. It's time for those arrays of 12-meter antennas to be built -- that would give the DSN so much more flexibility.

--Emily

"Spitzer, which trails Earth in its orbit, now needs the 70-meter dishes."

I did NOT know that - wow....that's a serious stretch on resources - I'd forgotten about that write up - it reads pretty much the same as the one I saw at IAC really.

Doug

While I'm very concerned about MGS, I'm not feeling the anxiety or anguish like I did with MPL and Beagle. To use a human analogy, while then death of anyone is tragic, the death of a small child seems especially so considering the loss of all that potential - a whole life never realized. If MGS has passed, I'll be sad and lift my glass to her accomplishments. I've got my fingers crossed, though!

http://www.space.com/missionlaunches/061114_mgs_mro.html

There’s a feeling that maybe the well-used MGS felt it was time to sign off.

On the 10th anniversary of MGS in space—November 7—that’s the same day that MRO cranked up its primary science tasks.

“It really seems like there’s some fate involved in this,” Sidney said. “MGS knew it was time to retire.”


awwwwwww

It's like losing an old friend. I remember watching the aerobraking page way back when and following MGS' progress. It's the mission that really "cracked open" Mars for us to explore in my view. And many of us were able to actually tell the thing what to take photos of which was phenomenal. Lets hope it can be recovered as MOC is still a terrific instrument. It does, though seem like handing off the baton, given the timing.

I should also add in that if this process can be accomplished, it will be extremely difficult, and thus there isn't a fixed day assigned to make the attempt to photograph MGS, only that the attempt should be made reasonably soon, but not to disturb any critical science/ Phoenix endevours.

I was hoping they would use the last part of this funded mission to explore PHOBOS.

What's so difficult about it? Lookheed-Martin designs the slew and they tell you when to start imaging. At least, that's how the Odyssey image by MGS was done. Doesn't sound too hard to me.

One thing Emily pointed out in her blog is that the s/c has been out of contact for 9 days. Its orbit is not exactly nailed down anymore. HiRISE attempts to image the predicted locations might be futile, resulting in huge amounts of data of empty space. I'm actually pretty skeptical they'll be able to pull it off easily.

If I understood it right they're doing a kinda long exposure and hope that MGS will show somewhere on the picture and then they can deduce where it is and shoot in the rigth direction a few days later. Did I get it right?

Maybe they're planning on using some other instrument on MRO with a wider field of view first. Gee, which one could it be?

"We'll use HiRISE on Friday"
"We'll use CTX on Wednesday then HiRISE on Friday"
"We'll use a long exposure with HiRISE on Wednesday then a targetted observation on Friday"

The usual suspect media outlets have all reported one or more of those.....so it's been a bit confusing for the layperson.

Doug

Well, I'm afraid I have nothing definitive to tell you. Note that there are lots of players and we may not know, or need to know, what other teams are doing. Plans may be changing from day to day, and the media often misquotes sources anyway. Even I might not know for sure what my own instrument will be doing and when. I'd believe that images were taken when you see the images.

Not to beat a deceased equine excessively, but maybe this is a partial answer:

http://www.unmannedspaceflight.com/index.php?showtopic=3227

How would you propose to fly antennas many tens of meters in diameter, much less duplicate, in flight-qualified form, the sensitive receivers and megawatt transmitters used by DSN stations? After all, these orbital comm relays would in general be little closer to Mars than Earth, and would then have to send the data to Earth.

Good questions. I'm not sure if it would be feasible with RF unless 1) we can successfully develop & deploy very large collapsable antennae (the Galileo experience was instructive), 2) advanced DSP on the receiving end of all terminals involved could compensate for much lower transmitter power outputs, and 3) flight-qualified ultra-stable transmitters with very fine output frequency resolution could be developed.

This idea would work better with lasers; something like an MTO for at least each of the inner planets would provide the necessary link between active exploration missions & the new network. This network would be used almost exclusively for data return & housekeeping, freeing up the DSN for critical activities such as resolving the current MGS anomaly, early mission support, and tracking during cruise.

EDIT: Apologies if anyone saw a smiley instead of 2) above; this was not intended as a shot against Galileo, the message board just interpreted by original use of a letter plus a parenthesis as a smiley.

Teeny-tiny spacecrafts, great big universe.

Ephemeris data for Mars is pretty good, though we require more recent updates prior to sending final commands to make sure our targeting is correct. Spacecraft-to-spacecraft ephemeris is not so good because of the variable atmosphere, dynamics of the Sun-Mars-MGS-MRO system, and other factors.

Sure, it can probably be done, but it will be hard, especially when there is a regular science mission ongoing with other timely observations required, and a million little things just waiting to go wrong somewhere in the complex process.

If the Odyssey imaging by MGS was easy, then wow.

Agreed. The media provides a snapshot of what things were like at a specific moment in time. The situation is dynamic, however, with scores of people and several teams involved, all in addition to the team members who really want to hear back from their pride and joy. The situation is confusing, and everyone is trying to do what they can.

Sorry, not buying this. We had little difficulty imaging Odyssey with MGS, and MRO should be better in every respect than MGS (HiRISE has a wider FOV than MOC, MRO pointing control is much more accurate/stable, etc, etc.) Maybe it'll take a couple of tries, but it shouldn't be that big a deal. LMSS does most of the work anyway; they just tell you when to start imaging, no?

MGS had one thing that MRO doesn't, the exact knowledge of the spacecraft to photograph. THAT is the largest problem, which the space.com article got correct.

Also, I, who work with the HiRISE team, and have been paying really close attention to what's happening, honestly can say I don't know when the picture will take place, or which instrument will do it. I'd be willing to bet that either CTX or HiRISE will be the photographers, but there again, it's a big universe and a small spacecraft.