Launch News (Failure) Phobos-Grunt and YingHuo-1 atop Zenit-2 on November 8/9, 2011

[SiberianTiger]

To be fair, RisingFury is right in this case - you can't keep the probe in LEO for weeks. That it is still alive enough that a chance to rescue it exists, is a miracle and pretty rare. Usually, the batteries would already be drained, this time the deployed solar arrays help, but it is not known how good they help.

Correct, any hope exists only if it could be boosted to a high-apogee intermediate orbit and deploys its X-band receiver.

 

[Urwumpe]

Correct, any hope exists only if it could be boosted to a high-apogee intermediate orbit and deploys its X-band receiver.

Or if you can directly send it on its planned mission (with a short intermediate orbit), but I suspect, there are not many reserves in this spacecraft to compensate, so the high apogee orbit is the best choice we have.

 

[SiberianTiger]

An insider's information on NK forum (http://www.novosti-kosmonavtiki.ru/phpBB2/viewtopic.php?p=845868#845868):

The same story contunued...

It is confirmed that Nov 23rd an emergency data frame from onboard radio assembly of the transfer-cruise module was received from Perth, but not successfully decoded in Lavochkin. It is also confirmed, that a data frame of the same sort was received by Baikonur on November 24th. Since that moment no other attempt to make a link from either Baikonur of Perth failed. The spacecraft is numb.

Analysis of the emergency frame from the cruise stage was not too fruitful. It contained:

• Status of several specific devices from the radio assembly itself;
• Working voltages on the assembly's buses;
• Temperature readings in severals spots of the assembly;
• Confirmation of nominal state of the bus for data exchange with the CPU;
• History track of switching between the primary and emergency transmitters.

All these things gave no clue for finding the root of the overall emergency.

In addition (in response to some ideas spoken out at this forum, btw) few simulations were run on the test bench, trying to replicate fault of a star tracker or faulty reading of data from a star tracker. No such interruption of the flight program as observed in reality could be obtained that way. This took into account coupling of the control chains that initiate Main Prop Module's burn.

Not only Russian space defence, but USA space watching services have confirmed that the spacecraft is still holding Sun-facing attitude.

One of the current theories under scrutiny about the secondary emergency development is that appearance and disappearance of contact can be caused by setup of the power supply unit. When solar arrays fade out and buffer battery depletes, the power unit switches to the chemical battery that have almost half of the day's capacity. At this moment, buffer batteries are switched off. In this case a current will appear only when solar arrays are exposed to Sun again and disappear in a next occullation. Having the emergency state on board, buffers are not engaged when current from the solar arrays exists.

We are keeping up attempts to reestablish contact. The commands that are sent up: Download telemetry frame from Radio assembly (the same that worked once), download telemetry frame from the computer, switch on buffer batteries.

Nobody is dreaming about a flight to Mars already. The minumum goal we are sriving for is raising the orbit to get a chance to actually work with the spacecraft. Maximum is, you guess...

 

[T.Neo]

To be fair, RisingFury is right in this case - you can't keep the probe in LEO for weeks.

I'm not bothered whether RisingFury happened to be right or not, but rather by the fact that instead of quantifying the real factors involved in the situation he made a sarcastic comparison to a fictional spacecraft from a computer program.

I'm not suggesting in my so-called "infinite wisdom" doing anything to Phobos Grunt, nor am I trying to make unfounded assertions on what it can and cannot do or what state it is in. I'm just saying that you can't just glance at something and say "this is impossible".

 

[Urwumpe]

I'm not bothered whether RisingFury happened to be right or not, but rather by the fact that instead of quantifying the real factors involved in the situation he made a sarcastic comparison to a fictional spacecraft from a computer program.

I'm not suggesting in my so-called "infinite wisdom" doing anything to Phobos Grunt, nor am I making assertions on what it can and cannot do or what state it is in. I'm just saying that you can't just glance at something and say "this is impossible" (or for that matter, glance at something and immediately say that it is possible).

Your pride is not topic here, so either get yourself your own thread for discussing what is below your dignity, or simply focus on what matters here.

Also you are equally often using such stupid comparisons for your argumentations, so better work on yourself first.

 

[T.Neo]

simply focus on what matters here.

I'm not the one who brought up my "infinite wisdom, knowledge and experience" in the the Phobos-Grunt thread. :dry:

Also you are equally often using such stupid comparisons for your argumentations, so better work on yourself first.

Indeed. But I'm willing to admit to it, at least...

 

[Codz]

I'm just saying that you can't just glance at something and say "this is impossible".

You seem to think anything Orion can do is garbage, and all you've done is look at concepts and tests...

 

[RGClark]

I'd also imagine that the Earth->Venus->Earth->Mars trajectory would require a lot more mid course corrections than a direct Earth->Mars flight. Even if there wasn't this extra mass being tugged around, I'd imagine the RCS fuel would run out, or be extremely limited.

It's possible since this is would be a low propellant trajectory that the mid-course corrections could be done by the main engine itself.


Bob Clark

 

[T.Neo]

You seem to think anything Orion can do is garbage, and all you've done is look at concepts and tests...

I never said any such thing. Can we please re-rail the thread now?

If Phobos-Grunt is indeed recoverable, what should realistically be done with it?

 

[Urwumpe]

It's possible since this is would be a low propellant trajectory that the mid-course corrections could be done by the main engine itself.

No, not automatically. Real spacecraft engines have ignition limits and can run out of resources needed for operation, other than fuel. For example Helium gas for driving the valves and purging fuel lines after operation.

 

[RGClark]

Not true. There's no guarantee that the probe would last in good condition until any launch window opened. It wasn't even designed for LEO communications in mind. If you boost its orbit, you only risk losing contact and having it crash later.
Unfortunately I agree that a controlled reentry is the best option here. There's even a chance - though low - that parts of the probe could be recovered for analysis.

The word "best" can be interpreted in different ways. That may be the most likely option.
Still other options such as Mars orbit, or lunar or asteroid lander missions, while less likely, perhaps should still be investigated.
Further information about the spacecraft status would be needed to make that determination.


Bob Clark

 

[Ghostrider]

Not true. There's no guarantee that the probe would last in good condition until any launch window opened.

Well, then send it into solar orbit. Plenty of launch windows for this.

It wasn't even designed for LEO communications in mind. If you boost its orbit, you only risk losing contact and having it crash later.

Can it eject into solar orbit in one burn? At least if comms can be established, the components can be tested for eventual redesign. And the more fuel it burns, the less is left to crash.

 

[orb]

Spaceflight Now: Latest attempts to contact Phobos-Grunt yield 'no joy'

Discovery News: Stranded Russian Mars Probe Falls Silent (Again)

 

[dgatsoulis]

It's possible since this is would be a low propellant trajectory that the mid-course corrections could be done by the main engine itself. Bob Clark

No, not automatically. Real spacecraft engines have ignition limits and can run out of resources needed for operation, other than fuel. For example Helium gas for driving the valves and purging fuel lines after operation.

From what i understand, it turns out that you'd have to spend more fuel, to turn your data receiving antenna, back to your target (mission base), to get data "on the fly" than to have a pre-computed set of instructions.

 

[SiberianTiger]

An attempt to make contact with Phobos-Grunt was made today by Baikonur station, but the probe remained silent:
http://www.interfax.ru/politics/news.asp?id=218902

According to earlier information, tomorrow Perth station will work with PhG again.

 

[SiberianTiger]

http://www.zarya.info/Diaries/Misc/PhobosGrunt1.php#log

Wow.

Date|Station|Rev|Rise (UTC)|Set (UTC)|Elev (°)|Notes
Nov 29|Perth|323|00:40|00:46|5|Possible attempt to upload command to raise orbit, and to receive telemetry
Nov 29|Perth|324|02:12|02:21|43|Possible attempt to upload command to raise orbit, and to receive telemetry
Nov 29|Perth|325|03:46|03:53|7|Possible attempt to upload command to raise orbit, and to receive telemetry

 

[Cosmic Penguin]

http://www.zarya.info/Diaries/Misc/PhobosGrunt1.php#log

Wow.

Date|Station|Rev|Rise (UTC)|Set (UTC)|Elev (°)|Notes
Nov 29|Perth|323|00:40|00:46|5|Possible attempt to upload command to raise orbit, and to receive telemetry
Nov 29|Perth|324|02:12|02:21|43|Possible attempt to upload command to raise orbit, and to receive telemetry
Nov 29|Perth|325|03:46|03:53|7|Possible attempt to upload command to raise orbit, and to receive telemetry

It's confirmed via tweets from ESA on Twitter that controllers will attempt to raise P-G's orbit.

 

[SiberianTiger]

It's confirmed via tweets from ESA on Twitter that controllers will attempt to raise P-G's orbit.

Do you have a twitter link for this?

 

[orb]

Do you have a twitter link for this?

http://twitter.com/esaoperations

 

[SiberianTiger]

http://www.interfax.ru/news.asp?id=218967

Phobos-Grunt remains silent

Nov 29, 2011, 10:49

Moscow, Nov 29. INTERFAX.RU. Attempts to communicate with Phobos-Grunt probe stuck in low Earth's orbit undertaken Tuesday's morning and send it commands to raise its orbit have failed.

"We has few communication slots to issue it a command to boost its orbit. We did send the command, but for no avail yet", told Interfax in the press office of Roscosmos.

According to Roscosmos representative, works on restoring communications with the spacecraft and sending it commands will be continued.