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#680 by Blackstar on 28 Nov, 2011 18:18
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(Note: the Lavochkin presentation is included below. That's where the graphics showing the Russians' overly-ambitious planetary exploration plans are from.)
http://www.thespacereview.com/article/1980/1
Red Planet blues
by Dwayne A. Day
Monday, November 28, 2011
This past week, like a coma patient who suddenly moves a finger, Fobos-Grunt finally gave some signs of life. But chances are still good that the spacecraft will fall to Earth in a few months, and it is already producing hyperventilating news reports about the toxic meteorite.
However, the Fobos-Grunt story took an ominous turn soon afterwards with comments from Russian President Dmitri Medvedev. “Recent failures are a strong blow to our competitiveness,” Medvedev told reporters during an interview. “It does not mean that something fatal has happened, it means that we need to carry out a detailed review and punish those guilty.” That would have been bad enough, but Medvedev continued: “I am not suggesting putting them up against the wall like under Josef Vissarionovich (Stalin), but seriously punish either financially or, if the fault is obvious, it could be a disciplinary or even criminal punishment,” he said.
The Russians are currently 1 for 19 at Mars, which you’d think would convince them to pick a different planet, like Venus, where they’ve been more successful. In contrast, NASA has been amazingly successful at Mars, with three spacecraft currently operating there and another (knock on wood) on the way. But it is stupid for the United States to gloat over the Fobos-Grunt failure, and we can only hope that the Russians will be smart in how they recover from this stumble. They could start by learning from past American experience and failures.
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#681 by JimO on 28 Nov, 2011 18:21
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Anybody know the planned burn TIME?
If so, where will burn be in relation to ISS?
After the tank is jettisoned it will vent excess prop and will briefly be a very good observation target from the ground and from ISS.
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#682 by Chris Bergin on 28 Nov, 2011 18:32
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(Note: the Lavochkin presentation is included below. That's where the graphics showing the Russians' overly-ambitious planetary exploration plans are from.)
http://www.thespacereview.com/article/1980/1
Red Planet blues
by Dwayne A. Day
Monday, November 28, 2011
That was a very good read, not least because it deals with a question most of us would want addressing - such as what do they do next....possible cooperation and competition. -
#683 by Prober on 28 Nov, 2011 18:54
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Anybody know the planned burn TIME?
If so, where will burn be in relation to ISS?
After the tank is jettisoned it will vent excess prop and will briefly be a very good observation target from the ground and from ISS.
don't "they" need to inform someone before they go to the highest orbit?
This lack of information is what bothers me.
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#684 by Michael J on 28 Nov, 2011 18:54
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Well, that's one very brute-force method of checking out the computer system, the propulsion system and the power system all in one shot. It will also indicate if the hydrazine / nitrogen tetroxide tanks are still in good shape. If not...
This does seem like a rather desperate attempt. There's also the question of guidance: one of the suspected causes of the initial failure was the star trackers not working, or a least not getting a fix at the required time. I wonder if they can do a burn on sun sensors and IMU only ?
Still, they don't have a heck of a lot to lose. If it works, they buy a bunch of time, more sunlight, and longer com windows. If the propulsion system is dead, they aren't going anywhere anyway.
One the subject of color, here's some pictures posted on the NK forum:
http://www.novosti-kosmonavtiki.ru/phpBB2/viewtopic.php?t=12418
The propulsion module was also covered in foil http://www.universetoday.com/wp-content/uploads/2011/11/phobos-grunt-preparations.jpg
A poster on the seesat-l list suggested that flaring behavior could be used to determine orientation: http://www.satobs.org/seesat/Nov-2011/0342.html
It could be a risky attempt as well. If they don't have positive control of the spacecraft and there is an issue with its orientation, an orbit-raising maneuver could exacerbate its decaying orbit and bring it down sooner. -
#685 by savuporo on 28 Nov, 2011 18:58
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What kind of orbit would they be shooting for ? Just a slight raise to buy more time ?
Current orbit tracking here
and here -
#686 by Michael J on 28 Nov, 2011 19:01
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Quote
JimO link=topic=27289.msg834230#msg834230 date=1322508101]
don't "they" need to inform someone before they go to the highest orbit?
This lack of information is what bothers me.
Technically, under the Outer Space Treaty the Russian Federation is responsible for the space activities surrounding the space craft, and if this maneuver could potentially create a hazard in the outer space environment they would be mandated to consult with the international community. However, over the years this requirement has been somewhat ignored by the United States, the Russian Federation and China in favor of "Cold War rules." Still depending on the interpretation, it is debatable whether they would be required to inform the international community of what they are attempting. -
#687 by Blackstar on 28 Nov, 2011 19:08
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(Note: the Lavochkin presentation is included below. That's where the graphics showing the Russians' overly-ambitious planetary exploration plans are from.)
http://www.thespacereview.com/article/1980/1
Red Planet blues
by Dwayne A. Day
Monday, November 28, 2011
That was a very good read, not least because it deals with a question most of us would want addressing - such as what do they do next....possible cooperation and competition.
Thank you. Unfortunately, I think they are headed for trouble. That's because of several things. First, Medvedev's comments are exactly the kind of thing that sends people running. If you are a young engineer/scientist in their space program, barely making a living, and suddenly the president of your country is joking about shooting you, would you want to stay where you are or start sending your resume to ESA colleagues?
Second, their proposed future plans (just look at those slides--33 missions in 8 years!) are totally unrealistic. That indicates that this is a program that is not grounded in reality. They really need to get much better focused. But that may not be possible given all their other problems. -
#688 by Jim on 28 Nov, 2011 19:20
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don't "they" need to inform someone before they go to the highest orbit?
This lack of information is what bothers me.
Not really. who would they inform -
#689 by savuporo on 28 Nov, 2011 19:26
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don't "they" need to inform someone before they go to the highest orbit?
This lack of information is what bothers me.
Not really. who would they inform
Arquilians, of course. -
#690 by Svetoslav on 28 Nov, 2011 19:39
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http://www.novosti-kosmonavtiki.ru/content/news.shtml
According to Interfax, today Russian specialists have contacted Phobos-Grunt, but failed to obtain telemetry. -
#691 by Longhorn John on 28 Nov, 2011 20:07
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Come on you naughty spacecraft, start talking clearly!!
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#692 by tolis on 28 Nov, 2011 20:28
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http://www.novosti-kosmonavtiki.ru/content/news.shtml
According to Interfax, today Russian specialists have contacted Phobos-Grunt, but failed to obtain telemetry.
Does that mean they, in fact, have failed to contact it?
Tolis. -
#693 by Svetoslav on 28 Nov, 2011 20:34
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I have no idea, frankly..
http://www.russianspaceweb.com/phobos_grunt_launch.html#11_28
A ground station in Baikonur was to have its first opportunity to contact Phobos-Grunt around 17:00 Moscow Time for about seven-eight minutes. However the spacecraft would be in the sunlight for only about half of that pass.
... so I ask- maybe a beep? -
#694 by hop on 28 Nov, 2011 20:41
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Does that mean they, in fact, have failed to contact it?
Given an Nth hand report through the Russian press, that's certainly possible. OTOH it could also mean they received some response that didn't include telemetry: E.g. carrier but not data, or link broke up before they could actually get telemetry. -
#695 by tolis on 28 Nov, 2011 20:46
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ok, acknowledging receipt of uplinked commands but not
actually sending back any data. Well, from what i read
it's supposed to try to raise its orbit following commands
from the ground; perhaps there is no time for downlink anyway.
One sign of orbit raising would be if it's late on subsequent
overhead passes as predicted from various parts of the world. It probably
doesn't have much margin for any engine burn in the wrong direction.
That would be Mars 96 all over again.
Does someone have any idea which propulsion system is to be used?
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#696 by HIPAR on 28 Nov, 2011 20:50
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Does that mean they, in fact, have failed to contact it?
Tolis.
Let's get Larson's take on that
--- CHAS
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#697 by alk3997 on 28 Nov, 2011 20:58
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http://www.novosti-kosmonavtiki.ru/content/news.shtml
According to Interfax, today Russian specialists have contacted Phobos-Grunt, but failed to obtain telemetry.
Does that mean they, in fact, have failed to contact it?
Tolis.
We can only go by what is reported since we have nobody here who is directly in contact with the controllers. So, does "contacted Phobos-Grunt" mean they sent it a signal but didn't hear a response or does it mean we sent a signal and the response was a simple tone or carrier signal with no telemetry? Don't know.
As far as this burn is concerned, I suspect they would just do a +X LVLH burn in the direction of the orbital velocity. Not really a targeted burn, just adding velocity (which will raise the orbit). I supposed the attitude control system could also do the burn but that would leave less prop for later attitude control (if there is a later).
That they still can't get reliable communications (no telemetry in this instance) implies that they are still having power problems based on this and the other passes. For a simple +x burn they could do that in the sunlit part of an orbit while passing over Baikonur or Austrialia to attempt to get around any power issues.
But we really don't know much other than someone at ESA thinks the Russians are attempting to send a burn command to the spacecraft and that something happened that prevented Baikonur from getting telemetry from the spacecraft. Everything else is speculation.
Andy
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#698 by hop on 28 Nov, 2011 20:58
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ok, acknowledging receipt of uplinked commands but not actually sending back any data.
Please understand, I was just giving one possible interpretation of "contacted, didn't receive telemetry". I am not making any claim about what actually happened.
As far as planned burn goes, I don't think the publicly available information is sufficient to make any meaningful speculation. We don't know much about the state of the spacecraft, we don't know what the Russians got from the telemetry they did receive, we don't know what sort of burn they are trying to do.
The ESA statements indicate that they did not expect an immediate indication of success from their attempts to uplink the burn commands.
What a sad situation that our best source of information is ESAs twitter feed
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#699 by tolis on 28 Nov, 2011 21:05
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Funny!
Moving on to the sphere of the speculative for a moment, I wonder
if one can actually command the sample return segment to
separate from the rest of the stack and fire its rocket motor
as an engineering experiment. If all else fails and the thing is about to reenter
(or if regular two-contact is established but the upper stage or main engine
are not usable for some reason) it may turn out to be the only useful in-orbit
activity from the mission. In any case, that segment weighs about
300 kg as I recall (wet mass) so getting rid of it increases the rest of the spacecraft's DV capability (F=ma).
It's *speculative*.
Tolis.
