Author Topic: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011  (Read 413172 times)

Offline Jason1701

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #840 on: 11/12/2011 01:47 AM »
Had this mission launched a few years ago (prior to STS-125 after which the shuttle lost 39B and the ability to put two shuttles on pads simultaneously) how difficult would it have been to have mounted a rescue?

Seems like it would be difficult to plan a mission and fly it before this launch window expires.

Seems more likely the spacecraft could have been retrieved, returned to Earth, and flow for the next launch window.

Maybe not a practical topic for discussion on this forum, but fun to think about nonetheless.

Read back a few pages. The idea is completely uneconomical. Maybe it would be economical if PG cost twenty times what it did.

Offline simonbp

Source: http://satobs.org/seesat/Nov-2011/0110.html

"Phobos-Grunt: latest two TLEs suggest manoeuvring or venting"
Or, simply the orbit is being better constrained by more observations. IMHO that's more likely...
Don't know that much about orbits ......but looks like this one has changed since yesterday.......she just hit over two hundered miles up over Indoensia,and 216 over auz, then drops like 60 miles.  Hit Alt of 142 over Peru

The USSTRATCOM TLE orbits referenced above talk about a difference of ~350 m. The mean radius of the Earth is 6371 km, so a change of 0.006% of the semimajor axis (mean distance from Earth's center of mass). That's well within the error for one-day radar-only tracking orbital estimate. So again, that amount of change would be expected from an improvement with more data points in the array they use to fit the orbit with. That doesn't mean that it isn't changing, but it's too early to actually tell.

Offline Lee Jay

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #842 on: 11/12/2011 02:45 AM »
A couple things I don't understand.

All the observations from individuals seem to indicate it isn't tumbling.  If that's the case, then it's got to be actively maintaining attitude control.  How could it do that if the control system is in safe mode?

If it is actively controlling itself, do we know if the thruster configuration is such that doing so wouldn't have any net propulsive action?

Offline A_M_Swallow

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #843 on: 11/12/2011 02:48 AM »
The change over date was in October
Not in Russia or the US.

The time clock chip may have its own views on that.
"... On the last Sunday in October when the time first reaches 1:59:59 AM, it changes to 1:00:00 AM."

I agree that it is an unlikely cause.

Offline hop

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #844 on: 11/12/2011 03:06 AM »
All the observations from individuals seem to indicate it isn't tumbling.  If that's the case, then it's got to be actively maintaining attitude control.  How could it do that if the control system is in safe mode?
Safe mode would presumably include basic attitude control to keep the solar panels pointed at the sun, otherwise you'd have very little time to do anything about it.

Alternately, it might be in a relatively stable attitude by chance.
Quote
If it is actively controlling itself, do we know if the thruster configuration is such that doing so wouldn't have any net propulsive action?
I don't think anyone could know this without detailed modeling, and maybe not even then, since the forces acting on the vehicle are not well constrained. "no net propulsive action" is also not certain, ACS activity could explain the apparent altitude gain.

Offline just-nick

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #845 on: 11/12/2011 03:19 AM »
All the observations from individuals seem to indicate it isn't tumbling.  If that's the case, then it's got to be actively maintaining attitude control.  How could it do that if the control system is in safe mode?
Safe mode would presumably include basic attitude control to keep the solar panels pointed at the sun, otherwise you'd have very little time to do anything about it.

Alternately, it might be in a relatively stable attitude by chance.
If indeed it is "dead" and not actively maintaining orientation mightn't it have settled into a gravity gradient configuration, oriented long-axis perpendicular to the surface of the earth?

I usually associate gravity gradient with really long skinny things but didn't the original Explorers unexpected assume this pose (though they were pretty long and skinny!).

--N

Offline Sparky

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #846 on: 11/12/2011 03:27 AM »
YH1. What sort of maneuvering capability does it have? Could it be turned on inside the truss, and if so, used to slowly reorient, or conceivably adjust the orbit of FG? I realize that this is like using an electric scooter to move a dump truck, but I thought I'd ask.
Regardless of maneuvering capability, I would expect any activation of YH1 to require commanding FG first.

Do we know that for sure? (not that we know anything for sure at this point.)

If it could be activated, telemetry from it might give some useful information. Assuming it's batteries are charged, it should be able to stay active for a few hours. (Wiki says a Mars night pass of up to 8.8 hours was expected.)

Offline HIPAR

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #847 on: 11/12/2011 03:35 AM »
The change over date was in October
Not in Russia or the US.

The time clock chip may have its own views on that.
"... On the last Sunday in October when the time first reaches 1:59:59 AM, it changes to 1:00:00 AM."

I agree that it is an unlikely cause.

I'd be surprised if the spacecraft clock is referenced to any timezone.  Mission elapsed time starting at liftoff would make more sense for synchronizing events.

---  CHAS

Offline Nickolai

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #848 on: 11/12/2011 04:03 AM »
YH1. What sort of maneuvering capability does it have? Could it be turned on inside the truss, and if so, used to slowly reorient, or conceivably adjust the orbit of FG? I realize that this is like using an electric scooter to move a dump truck, but I thought I'd ask.
Regardless of maneuvering capability, I would expect any activation of YH1 to require commanding FG first.

Do we know that for sure? (not that we know anything for sure at this point.)

This document: http://www.novosti-kosmonavtiki.ru/phpBB2/viewtopic.php?t=12378 (posted earlier) states that the return capsule and the Chinese probe are turned on in a standby state AFTER the propulsion system sends the stack onto an interplanetary trajectory. (middle of the second page)

Offline olasek

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #849 on: 11/12/2011 06:46 AM »
So you would have as much chance as the President of the United States and the four Beatles performing the rescue mission themselves as you would being able to launch this so-called rescue mission during the current launch window.
Well said. And NASA would never agree to take cargo as dangerous as PG with 7 tons of toxic propellants, cargo of dubious value, possibly leaking, where no human life is at stake, you would really have to be super naive to think they would even spend a minute considering such a mission.

Offline geza

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #850 on: 11/12/2011 07:25 AM »
If this mission is lost (I still hope it isn't...) then it must be repeated and try again - after the cause of mishap has been found and corrected. Well, they may want to take a second look on all other steps this s/c are supposed to make...

Assume success. Then, why don't consider a derivative of PG as an element of an international Mars Sample Return? Current planning for MSR calls for three independently launched elements: (1) a rover collecting the sample, (2) Mars Ascent Vehicle delivering the sample to Mars orbit, (3) Earth Return Vehicle that fetches the sample from the ascent element and delivering to Earth. PG would be an excellent starting point for ERV.

Offline Jorge

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #851 on: 11/12/2011 07:37 AM »
So you would have as much chance as the President of the United States and the four Beatles performing the rescue mission themselves as you would being able to launch this so-called rescue mission during the current launch window.
Well said. And NASA would never agree to take cargo as dangerous as PG with 7 tons of toxic propellants, cargo of dubious value, possibly leaking, where no human life is at stake, you would really have to be super naive to think they would even spend a minute considering such a mission.

Right. They wouldn't agree to do EVA servicing on it, either, since the spacecraft wasn't designed to be safe for it (sharp edges, lack of handholds, would need a training-fidelity NBL mockup, etc). Even postulating a what-if scenario where the shuttle was still flying and Phobos-Grunt were somehow stabilized in an orbit that wouldn't decay for the two years required to plan a shuttle mission, there is no way NASA would do it. It simply wouldn't happen.
JRF

Offline Svetoslav

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #852 on: 11/12/2011 07:48 AM »
http://www.interfax.ru/society/news.asp?id=216504

Interfax reports that the latest attempts to contact the spacecraft (the attempts made during the night between Friday and Saturday) have failed.

The European communication base will try to contact the spacecraft today. Does this mean that they won't send the commands from Baykonur, or the European base will be just listening... I don't know...

Offline input~2

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #853 on: 11/12/2011 07:49 AM »
From the last two elsets (epoch Nov11 19:59:48 and Nov 12 01:59:22), Ph-G's mean motion has started increasing again (ie the orbit semi major axis is decreasing again)

Offline Svetoslav

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #854 on: 11/12/2011 07:57 AM »
http://ria.ru/science/20111112/486873708.html

RIA Novosti confirms the story of Interfax.

A source from the space industry also says that the "American colleagues" have confirmed that the spacecraft is currently in Solar orientation and if they find a way to communicate with it... they will be able to reprogram it and send it on the way to Mars...

They are just trying to "break through" the controls of the spacecraft.

Offline yamato

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #855 on: 11/12/2011 09:55 AM »
As I understand it, the probe is OK, it just can't receive and transceive signals.
Would it help if the probe changed its orientation? Maybe they could use some laser to create artificial sun, on which the probe would reorient (99% its a stupid idea, but I had to ask :))

Offline Rocket Science

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #856 on: 11/12/2011 11:33 AM »
A couple of minutes old...

Difference in opinion in our friend JimO and Russian officials

The spacecraft weighs 14.6 tons, and most of that weight (about 12 tons) is a highly toxic mix of nitrogen teroxide and hydrazine fuel.

The Russians are hoping the fuel will stay liquid when the probe comes down, harmlessly exploding about 50 miles above ground.
But experts like James Oberg, a NASA veteran who now works as a space consultant, think the fuel could freeze, surviving the fiery re-entry and causing an environmental disaster on impact.

He said the probe would become 'the most toxic falling satellite ever', adding: 'What was billed as the heaviest interplanetary probe ever may become one of the heaviest space derelicts to ever fall back to Earth out of control, an unenviable record


http://www.dailymail.co.uk/sciencetech/article-2060443/Phobos-Grunt-Mars-probe-Russias-dream-ends-toxic-nightmare-begins.html?ito=feeds-newsxml
« Last Edit: 11/12/2011 12:12 PM by Rocket Science »
"The laws of physics are unforgiving"
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Offline Liss

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #857 on: 11/12/2011 11:55 AM »
As I understand it, the probe is OK, it just can't receive and transceive signals.
Would it help if the probe changed its orientation? Maybe they could use some laser to create artificial sun, on which the probe would reorient (99% its a stupid idea, but I had to ask :))
It is not correct to say the probe is OK. She suffered some unknown failure between her second pass and the scheduled first burn time. We know she is not talking since, visual observations suggest she's steady and orbital elements show some evolution, most probably from control system trying to do something.
It is not known if she can hear and understand us. Commanding was obviously not planned for such orbit. Attempts are being made nevertheless.
« Last Edit: 11/12/2011 11:55 AM by Liss »
This message reflects my personal opinion based on open sources of information.

Offline alk3997

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #858 on: 11/12/2011 12:35 PM »
As I understand it, the probe is OK, it just can't receive and transceive signals.
Would it help if the probe changed its orientation? Maybe they could use some laser to create artificial sun, on which the probe would reorient (99% its a stupid idea, but I had to ask :))

Let's use our automobile analogy again...It's equivalent to saying that the steering wheel is apparently working and the front tires move but the engine is dead, the radio and horn don't seem to work, we don't know if the A/C is good and there are some other unknown problems that keep the car from starting.  I don't think I would describe this automobile as "OK".

It appears there is now data that says the automatic orientation system is working because of the lack of flashing detected by ground observers.  That would then indicate that there is power onboard (at least partial power), the spacecraft can sense its attitude, the attitude control function of the computer systems is working, the propellant system is operational and the attitude control jets are operational.  However, you still don't have any way to tell the spacecraft what to do and its automatic mode isn't going to cause the spacecraft to get any closer to Mars than it already is.  You're also rapidly approaching a point where orbital mechanics will prevent the spacecraft from being able to reach Mars even with a miraculous recovery of all spacecraft functions, diagnosing what happened with the original burn attempt (remember there is still no fix for the original problem that prevented the burn) and then re-program the spacecraft (assuming that the problem can be bypassed) to send it in the right direction with the exact newly calculated change in velocity needed to reach Mars (which is now different from the velocity change needed at the time of the launch).  That's a lot to ask of a spacecraft that has no communications capabilities at the present time.

One thing for sure is that without communications, the spacecraft is going nowhere except back to the Earth.  I wonder if the Fobos-Grunt return capsule will survive re-entry?  Guess it depends on the return capsule's attitude as it comes off the spacecraft body during the re-entry.

Andy
« Last Edit: 11/12/2011 01:14 PM by alk3997 »

Offline Rocket Science

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #859 on: 11/12/2011 12:58 PM »
Perhaps Russia can use their technology to take dawn their own ailing bird…

http://www.thespacereview.com/article/1865/1
« Last Edit: 11/12/2011 01:01 PM by Rocket Science »
"The laws of physics are unforgiving"
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