Author Topic: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011  (Read 641599 times)

Online ugordan

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #880 on: 11/12/2011 04:43 pm »
With another upper stage booster failure, are there any new concerns regarding tomorrows manned launch?

1. It's not an upperstage, certainly not a stock upperstage.
2. Who says it's a booster failure?
3. It's got absolutely nothing to do with Soyuz and its flight profile.

Offline alk3997

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #881 on: 11/12/2011 04:48 pm »
With another upper stage booster failure, are there any new concerns regarding tomorrows manned launch?

No, different launch vehicle and upper stage.  Using the automobile analogy again (and my appologies to Toyota), just because Toyota had a steering wheel recall due to a defective part, doesn't mean that all other cars made by GM/Fords/Jaguars/Hondas have that same defect.  Not even all Toyotas have the same defect.

Every launch vehicle and upper stage is unique unless they share a similar heritage.

« Last Edit: 11/12/2011 04:49 pm by alk3997 »

Offline ChileVerde

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #882 on: 11/12/2011 05:01 pm »
New results and analysis from Ted Molczan. Something definitely seems to be going on with the orbit.

http://www.satobs.org/seesat/Nov-2011/0131.html

Summary:
Quote
USSTRATCOM has issued three new TLEs since my comments yesterday on the payload's rate of decay. They confirm that the apparent small increase in orbital altitude is real, and apparently it is continuing.

Prior to the onset of this effect, which became evident in the TLEs issued after epoch day 11314.76789777, the rates of decay of the payload and its rocket body were roughly proportionate to their respective area to mass ratios, as would be expected for bodies encountering nearly identical atmospheric density, due to their nearly identical orbits.

Much interesting analysis snipped, but is recommended reading.

Edit: Fix line lengths
« Last Edit: 11/12/2011 05:02 pm by ChileVerde »
"I can’t tell you which asteroid, but there will be one in 2025," Bolden asserted.

Offline renclod

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #883 on: 11/12/2011 05:28 pm »

It [Progress] can't do the relay task any better unattached from the ISS than attached.  Zero and zero ability.

Even so... if a -generic- agile spacraft could be quickly moved to station keeping with F-G, is there any way it could -in theory- help ?

1/ by obstructing the Sun from the F-G sensor; could force the flight computer to do something new ?

2/ by acting as a (*) reflector/amplifier for radio waves originating from ground ?

edit: (*) passive
« Last Edit: 11/12/2011 06:23 pm by renclod »

Offline Jim

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #884 on: 11/12/2011 05:46 pm »

So sending an observer is too dangerous then? If we are not developing facilities to respond to 'unexpected' unexpected rescue missions in space, now and in the future, then maybe we should just pack our bags and go home.

What observer?  Why?  To waste more money?  No, it is not worth the cost to develop such facilities.  The ROI is not worth it

Offline Vladi

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #885 on: 11/12/2011 05:57 pm »
According to some people in NK (ones that have to do with space, including some Lavochkin guys) the other problem is that the spacecraft uses X band and from all the ground antennas available configured to woek with the craft, the smallest one is 64m wide. This means that it could not possibly track a spacecraft so close and hitting the spacecraft with the beam (it is very narrow from that antenna) is quite difficult and requires precise knowledge of the orbit and a lot of luck. Even if you hit FG with the beam, it will pass out of it quickly, so you cannot get telemetry down or commands up. S band receiver/transmitter would have been a nice addition. Although after so many attempts people are beginning to think that at least once the craft should have got the commands from the ground, so possibly something physically went wrong with the craft and that caused some damage to the comms system.
I have no idea if that makes any sense.

Offline alk3997

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #886 on: 11/12/2011 05:58 pm »

It [Progress] can't do the relay task any better unattached from the ISS than attached.  Zero and zero ability.

Even so... if a -generic- agile spacraft could be quickly moved to station keeping with F-G, is there any way it could -in theory- help ?

1/ by obstructing the Sun from the F-G sensor; could force the flight computer to do something new ?

2/ by acting as a reflector/amplifier for radio waves originating from ground ?



This isn't Star Trek where you can just blindly maneuver to every orbital position.  What propellant are you going to use to get there?  How are you going to maintain your relative position?  How are you going to command a spacecraft whose receiver may be dead (not just antennas obstructed).  Who's going to pay the cost of doing all this work?

Please re-read your append and figure out what each step would buy you.  None of this results in a reasonable chance of a spacecraft going to Mars.

Offline Sparky

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #887 on: 11/12/2011 06:03 pm »
New results and analysis from Ted Molczan. Something definitely seems to be going on with the orbit.

http://www.satobs.org/seesat/Nov-2011/0131.html

Summary:
Quote
USSTRATCOM has issued three new TLEs since my comments yesterday on the payload's rate of decay. They confirm that the apparent small increase in orbital altitude is real, and apparently it is continuing.

Prior to the onset of this effect, which became evident in the TLEs issued after epoch day 11314.76789777, the rates of decay of the payload and its rocket body were roughly proportionate to their respective area to mass ratios, as would be expected for bodies encountering nearly identical atmospheric density, due to their nearly identical orbits.


So it seems that this might be some good news, since if it is climbing, this will allow longer windows for comm attempts, and of course, delay it's inevitable entry.

One thing that occurs to me is that Fobos-Grunt is not a particularly symmetrical. If it were venting from anywhere other than near the main engine, wouldn't this cause spinning?

Another is that if this is venting, would it not likely be from the torus-shaped drop tank that was not intended to last more than a few hours?

Offline Jim

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #888 on: 11/12/2011 06:05 pm »

It [Progress] can't do the relay task any better unattached from the ISS than attached.  Zero and zero ability.

Even so... if a -generic- agile spacraft could be quickly moved to station keeping with F-G, is there any way it could -in theory- help ?

1/ by obstructing the Sun from the F-G sensor; could force the flight computer to do something new ?

2/ by acting as a reflector/amplifier for radio waves originating from ground ?



What agile vehicle?  And how many of those have X-band relays?  Actually, there is no such capability that exist

US Mars orbiters have an UHF relay for landers.  TDRSS has S and KU.

Offline Jim

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #889 on: 11/12/2011 06:08 pm »

1/ by obstructing the Sun from the F-G sensor; could force the flight computer to do something new ?


To make it just aimlessly search for the sun and expend propellant

Online ugordan

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #890 on: 11/12/2011 06:10 pm »
So it seems that this might be some good news, since if it is climbing, this will allow longer windows for comm attempts, and of course, delay it's inevitable entry.

It's gonna be a long while before this modest (if real) altitude increase leads to better comm windows. By that time the Mars launch period will be long over.

One thing that occurs to me is that Fobos-Grunt is not a particularly symmetrical. If it were venting from anywhere other than near the main engine, wouldn't this cause spinning?

Another is that if this is venting, would it not likely be from the torus-shaped drop tank that was not intended to last more than a few hours?

It's not out of the question that it's both slowly venting, but maintaining three axis control (meaning it's alive).

Offline Sparky

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #891 on: 11/12/2011 06:25 pm »
It's not out of the question that it's both slowly venting, but maintaining three axis control (meaning it's alive).

So at least it is nearly certain that the vehicle is still alive in some capacity, and not merely retaining it's attitude by chance, as some have suggested.

Since the spacecraft was intended for a long cruise to Mars anyway, is waiting until the next launch window out of the question? Another 18 months *might* allow for the launch of a tug (possibly Progress derived) to push FG into TMI (to make up for propellant losses during that time).

Offline yamato

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #892 on: 11/12/2011 06:30 pm »
maybe some satellite observers could try to make some images, to bring some new light



Sparky - developing such a tug would cost more than brand new phobos-grunt

Online ugordan

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #893 on: 11/12/2011 06:31 pm »
Since the spacecraft was intended for a long cruise to Mars anyway, is waiting until the next launch window out of the question?

Hard to say without knowing how some components (such as the drop tank) would hold up for such an extended period of time. Also, delta-V requirements for the next Mars launch opportunity probably won't be the same.

Quote
Another 18 months *might* allow for the launch of a tug (possibly Progress derived) to push FG into TMI (to make up for propellant losses during that time).

Highly unrealistic.

Offline input~2

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #894 on: 11/12/2011 06:33 pm »
So it seems that this might be some good news, since if it is climbing, this will allow longer windows for comm attempts, and of course, delay it's inevitable entry.
According to today's elsets, it's not really "climbing", it is at best maintaining its average altitude, with a steady period of 89.96 minutes

Offline Svetoslav

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #895 on: 11/12/2011 06:36 pm »
I wonder if it means raising the orbit on purpose

Offline hop

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #896 on: 11/12/2011 06:52 pm »
According to some people in NK (ones that have to do with space, including some Lavochkin guys) the other problem is that the spacecraft uses X band and from all the ground antennas available configured to woek with the craft, the smallest one is 64m wide.
If this is true, it seems like a case where US or other outside parties could possibly help. NASA, ESA, and JAXA all have X band grounds stations AFAIK.

I wonder if it means raising the orbit on purpose
Seems unlikely something it would decide to do on it's own in safe mode, but possibly a side effect of maintaining attitude.

Offline Space Pete

Latest article from AFP:

Quote
"All attempts to obtain telemetric information from the Phobos-Grunt probe and activate its command system have failed. The probe must be considered lost," Interfax quoted a source in the Russian space sector as saying.

The source said Russia's space agency would announce the failure of the mission in the next few days.

http://www.google.com/hostednews/afp/article/ALeqM5gMW4kePeuEcETL4ubT0UUDyRBoww?docId=CNG.cbc3ed79698bb9cab8ad6a92169ceb0c.01
NASASpaceflight ISS Editor

Offline hop

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #898 on: 11/12/2011 06:59 pm »
Since the spacecraft was intended for a long cruise to Mars anyway, is waiting until the next launch window out of the question?
A far more likely scenario would be to attempt an earth flyby trajectory like Nozomi. IMO, this should be a real possibility if they regained control, although of course it would require much longer operation in deep space than the original plan.
Quote
Another 18 months *might* allow for the launch of a tug (possibly Progress derived) to push FG into TMI (to make up for propellant losses during that time).
This is absurd. There's no docking mechanism on FG for starters. By most accounts, FGs major fault is insufficient time for testing and analysis, and that's after many years of development including a two year delay. Now you are proposing designing and building an entirely new, unique spacecraft in only two years. It would be nice if people would stop and think for a few minutes before posting their wild ideas...

Offline sdsds

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #899 on: 11/12/2011 07:34 pm »
The high-speed, 34 m antenna at Goldstone, (the "HSB" antenna) has the fastest tracking and slew rates of any DSN antenna.  Its slew rates (in deg/s) are 3.0 (AZ) 2.0 (EL).  I haven't done the math, but the attached graph seems to imply tracking FG on at least some passes would be within its capabilities.  (Info and graphic from: http://deepspace.jpl.nasa.gov/dsndocs/810-005/302/302B.pdf.)
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