http://digilander.libero.it/SATrack/Phobos.html?q=phobos#MAP

http://satobs.org/seesat/Nov-2011/0158.html

It seems that perigee is rising.

Some orbiting satellites have X-band transmitters and receivers. As a shot in the dark, I wonder if a transmission from one of these might have a better chance of reaching Phoebos-Grunt than the slow ground stations, if the satellite could be made to rotate in a way that tracks the moving spacecraft. [Edit: the British skynet satellite seems to have an xband with a wide beam width.]

This is good news in the sense it constrains many problem scenarios, and buys time for engineers to understand both the communications fault and then understand the problem with why the cruise engine did not fire. Unfortunately, it seems like the communication problem is not well understood at all.

I'm not sure we can say for certain that the communication problem is not well understood. The problem is that they have no assets designed for commanding deep-space craft occupying low-Earth orbits. Their ground stations can't track fast enough, it's hard to acquire and communicate in the short windows. The ground stations' beam width is so narrow that uncertainty in orbital position can place the spacecraft outside the beam. The ground stations broadcast so powerfully that they may somehow fry the spacecraft systems. There are lots of issues and not a lot of time to solve them. ESA is helping out but their ground stations all have the same problems.

We still need a "like" button here...perfect summary, Emily.

No possibility of a relay with earth orbiting satellites in a better position? Would it take too long to set up, or are there technical incompatibilities of some sort?

I don't recall if anything like this ever happened before; this may be the first of event its kind, at least as far as planetary exploration is concerned...

To get downlink, they need to be able to command it.

We don't really know what's happened, so we can't really compare it to previous missions.

But - under the assumption that PG is actually healthy but the Fregat upper stage refused to fire up again......

Ranger 1 and 2 both ended up stranded in LEO as their Agena upper stage didn't fire to leave LEO to head toward the moon, so could certainly be considered of a similar type.

Mars 96 was an upper-stage failure, and given that the Fregat that should be sending PG on it's way is also an upper stage and could be considered even more similar.


"first of event its kind"

Depending on how you define 'kind' and given the uncertainty of what we know about PG...then, no, I don't think it's the first event like this.

I think Explorer1 may have been wondering whether contacting a spacecraft from a satellite is unprecedented. It is not unprecedented, as that's exactly what TDRSS does.

If it's a software glitch that can't be fixed because of the difficulty of getting telemetry to it because it moves across the sky too fast would it be the first of that kind? If so it surely could be one of the learning moments nprev talks about.

(Hey - I still hope they may rescue it.)

PS: Could it survive being parked for a couple of years before being sent to Mars?

Atmospheric drag will drop it out of orbit in a month or so....and if you had the control authority to raise the altitude to overcome that, then I assume you would also have the control to tell it to get to Mars already.

There are fairly large antennae that regularly track vehicles in LEO for downlink - indeed, some of the BWG's at Goldstone are specifically called High Speed BWG's - for their high speed tracking. ( DSS 27 and 28 )
From http://deepspace.jpl.nasa.gov/dsndocs/810-005/104/104F.pdf
"The HSB antenna differs from the BWG antennas in that the pedestal room is
above ground level, the microwave optics design is different, and the subreflector does not focus
automatically for the purpose of maintaining gain as the elevation angle of the antenna changes.
The HSB antenna has higher tracking rates than do the BWG antennas and is equipped primarily
for tracking Earth-orbiting satellites."

Those antennae could happily receive a signal from the MER low gain antenna at Mars. Surely they could, if it were transmitting, hear PG? And if they, like the other BWG's - can transmit at 20kw... I'm fairly sure that if it were listening...PG could hear it.

The challenge is, is there something unique about the PG telecoms system that is different from normal DSN ops for interplanetary or Earth Orbiting assets? I'm sure these antennae have the physical characteristics to do this job - do they have the back-end facilities to do it, that's the question.

D

I suppose you could imagine a scenario where control authority is regained after the Mars window closes, so the spacecraft could be placed in a stable orbit to wait for the next Mars window two years hence. It seems like a long shot, but no crazier than the plan that eventually brought Hayabusa home.

John

That's a good call....but then, another 2 years or so on LEO, it'll have consumed a bunch of prop for attitude control. But as you say - no more crazy than Hayabusa.

I assume Doppler effects are taken into account in these cases.

I'm sure they have, although I wonder if the rapidly changing Doppler frequency from an orbiting craft is another problem with acquiring a lock using antennas designed to work with craft in deep space?

Has anyone heard anything about Yinghuo-1? I assume being an independent orbiter, it has its own transmitter/receiver capable of talking direct-to-Earth. I know it's pretty small, but maybe if the Chinese can talk to it they can use it to boost Phobos-Grunt to a longer-lasting orbit. Or try to reorient the spacecraft so that the main transmitter is more favorably oriented? If it pointing to the Sun, is it possible the transmitter is on the wrong side of the spacecraft? For Mars orbit, the spacecraft would be pointing away from the center of the orbit, but from Earth orbit wouldn't it have to face the other direction to see the ground stations?

Or maybe they could talk through Yinghuo to P-G? There must be some kind of communication/power interface between the two, but it isn't likely that it is designed to handle this kind of operation.

Yinghuo-1 has no orbit change capability of its own, so it can't be used to adjust the orbit of the combined vehicles.

Phil

Another scenario intermediate between total mission success and total failure
would apply to the case where the spacecraft has enough fuel for
Trans-Mars Injection and Mars Orbit Insertion but insufficient to match orbit
with Phobos after MOI.
Then we are looking at successful release of Yinghuo-1 and some
kind of orbital mission after that, possibly involving multiple flybys of Phobos and Deimos.
In that case it would be wise to lose the sample return capsule as early as possible
in the mission (even as early as the Earth orbiting phase) in order to lose mass and
hence gain delta v.

Of course, all these scenaria depend on the russians regaining the ability to command
the P-G/upper stsge assembly. After so many days of failing to do that, I find
it difficult to hope that any of the mission objectives will be recovered, either in whole
or in part. Still, there is time left on the clock..


Tolis.

http://www.newscientist.com/article/dn2117...in-january.html

According to this New Scientist article, NASA may join the attempt to contact Phobos-Grunt, using the DSN.

"The world's telescopes are still trying to contact a Russian space probe".....the author obviously has no idea what a telescope is.......

I guess he's referring to the DSN radio receivers as radio telescopes, which they can be used as. Not the best use of terminology but maybe he thought it was a good way to lump the optical and radio searches together in one phrase.

(edit: DSN radio dishes are not yet being used, just Russian ones.)

safe mode (description):

The spacecraft is transferred to SO and stabilized. The accumulator is charged by SB. The power-consuming systems, running at MDU (main propulsion unit) from HIT (chemical battery): RPT111 (telemetry transmitter) and RDM (trajectory measurements), are off and can be turned on by the command from BVK (flight computer) or directly from the cruise stage radiocomplex (BRK PM).

BRK PM is up and running constantly in the receiving mode. Switching to the transmitting mode is possible at any time upon receiving a request from ground station. Also in the safe mode BRK PM performs autonomous transmitting of the TM data, lasting about 40 minutes every 2 hours for 8 days.

http://www.novosti-kosmonavtiki.ru/phpBB2/...p=839522#839522
( and many other usefull information in russian)

Would it not be possible to bounce a DSN signal off the moon to awake the spacecraft? Larger signal cone and weaker signal strength could both work out favorably...

That suggests that the spacecraft may actually have been transmitting telemetry periodically all along, but the ground stations have so far been unable to pick it up due to technical limitations. Is that possible given what we know? If this is true, then some assets may want to concentrate on receiving. [EDIT: I think the 8 day period ends about 4 hours from now?]

I had posted a question about alternate targets for Phobos-Grunt like earth's moon or NEO in this thread, but it seems to have disappeared, along with a couple of responses to my question.

This universe today article says:

I was going to suggest something like this earlier, but didn't know how plausible it is. Stranger things have happened...

I know nothing about the nuts and bolts of the communications problems, but the fact that over a week has gone by without any successful communication whatsoever with the spacecraft leaves me feeling very pessimistic indeed. I just hope the controllers get a break...

Thanx Brellis for the info from Universe Today. We've seen amazing 'saves' for several missions, from Mariner 7 to Hyabusa. I'll continue to quietly pull for their team to have that 'aha moment' and amaze us all with any level of success.

P/G is hanging in there if it can be saved some how it would be nothing short of amazing.

I'm really rooting for them, and I'm utterly certain that they're trying everything they can possibly think of to save the mission.

All we can do is hope.

Latest from RIA Novosti- almost a "zero percent chance" of reviving Phobos-Grunt.

Interesting to note that the solar panels are deployed and the spacecraft is in "barbeque mode."

Although it's probably true that there's no chance of getting Phobos-Grunt to Mars, you have to watch out for these stories quoting unnamed "experts" and "sources." In some cases these "sources" have proven to be....online forums.

http://www.space.com/13710-phobos-grunt-re...me-running.html

Some new information. NASA and ESA are both trying to help. Deadline for Mars trajectory is apparently Nov 24.

Interesting. Thanks!

ESA in Perth have received a signal apparently

YES ! Hope dies last

ESA web:
On Tuesday, 22 November at 20:25 UT, ESA's tracking station at Perth, Australia, established contact with Russia's Phobos-Grunt spacecraft. This was the first signal received on Earth since the Mars mission was launched on 8 November. ESA teams are working closely with engineers in Russia to determine how best to maintain communication with the spacecraft. More news will follow later.

Although it doesn't say what kind of contact, whether they were able to communicate with as planned

From Ria Novosti (translated by Svetoslav on NSF) :
"The signal has been received during one of a total of four attempts to reach the probe. The signal was received when Phobos-Grunt was illuminated by the Sun. This evening European and Russian specialists will continue working so they can establish a reliable communication with the spacecraft."

More infos there: http://www.spaceflightnow.com/news/n1111/23phobosgrunt/

BBC News has some more bits of information:
http://www.bbc.co.uk/news/science-environment-15850516

According to the BBC, Perth had to reduce power to contact the spacecraft, and also widened its beam to allow for orbital uncertainties. Details here [Astrophil beat me to the link]:

http://www.bbc.co.uk/news/science-environment-15850516

"We were able to get our transmission in and the commands that were sent then allowed the transmitter on the spacecraft to be turned on; and then we saw the signal coming back into our big dish," explained Dr Klaus-Juergen Schulz, the head of the ground station systems division at Esa-Esoc.

"We also made some radiometric measurements to derive a more precise orbit. This should make it easier to contact Phobos-Grunt in future. The next pass is at 2019 [GMT]."

An article on the ABC website (Australian Broadcasting Corporation, our equivalent to the BBC)...

http://www.abc.net.au/news/2011-11-24/pert...s-probe/3690328

the latest pass would have happened some hours ago. Fingers crossed.

From ESA :
http://www.esa.int/esaCP/SEM4NEZW5VG_index_0.html

http://en.ria.ru/world/20111123/168974896.html

A report from Russia. If this is accurate, Perth was not set up to receive detailed telemetry when it made contact.

According to RIA news, the telemetry is received!

http://www.ria.ru/science/20111124/496387514.html

Reason for hope!

Here's Google translation of part of the RIA article cited by Daba:

Chilling a bottle of my best vodka in case we have reason to celebrate over the next few days.

according to NK-forum the TMI frame was received from the cruise stage radiocomplex, next attempt - to receive data from BKU.

If you need any more ice...

Don't need ice. Just leaving it outside today (brrrrr......)