Author Topic: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011  (Read 426626 times)

Online hop

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #660 on: 11/10/2011 09:39 PM »
Does the X-37B have any relay capability?  I know that's classified but just throwing it out there.
If a 10+ meter dishes on the ground with many kw of transmit power can't do it, it's extremely unlikely that some dinky radio on a spacecraft would do better, even if it were theoretically possible.

Offline Prober

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #661 on: 11/10/2011 09:55 PM »
Does the X-37B have any relay capability?  I know that's classified but just throwing it out there.   They are both pretty much over Australia right now. ???

 http://www.n2yo.com/?s=37872

http://heavens-above.com/orbit.aspx?satid=37375&lat=0&lng=0&loc=Unspecified&alt=0&tz=CET

This is a tad more fun.....watch ISS, PG, & OTV2   

http://www.n2yo.com/?s=25544|37872|37375
« Last Edit: 11/10/2011 10:02 PM by Prober »
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Offline Robotbeat

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #662 on: 11/10/2011 10:02 PM »
Does the X-37B have any relay capability?  I know that's classified but just throwing it out there.   They are both pretty much over Australia right now. ???

 http://www.n2yo.com/?s=37872

http://heavens-above.com/orbit.aspx?satid=37375&lat=0&lng=0&loc=Unspecified&alt=0&tz=CET

This is a tad more fun.....watch ISS, PG, & OTV2    Intersection shortly.
http://www.n2yo.com/?s=25544|37872|37375
Thanks, I was wondering how to set that up...
(your link is sort of broken... you need to put [url] and  [/url] around the whole thing, though... here's a fixed version:

http://www.n2yo.com/?s=25544|37872|37375 )

Do they know the orientation of Phobos-Grunt? Would that information be helpful?
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Offline JimO

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #663 on: 11/10/2011 10:03 PM »
I have a overhead pass tomorrow PM and a good set of binoculars. Anything I can do?

I have some dawn sighting opportunities in the days ahead
which I intend to work diligently.

Observe for nearby objects leading or trailing.

Observe for light fluctuations, both periodic and occasional.

Observe for indications of propellant leak.

Offline 93143

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #664 on: 11/10/2011 10:10 PM »
If a 10+ meter dishes on the ground with many kw of transmit power can't do it, it's extremely unlikely that some dinky radio on a spacecraft would do better, even if it were theoretically possible.

I was under the impression that the problem was line-of-sight.  With a clear shot at the antenna, you wouldn't need more power than the ground station, or (most likely) even as much.
« Last Edit: 11/10/2011 10:13 PM by 93143 »

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So are we all on side with the reports that we'll know one way or the other over the next few hours?

Offline alk3997

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #666 on: 11/10/2011 10:13 PM »
I have a overhead pass tomorrow PM and a good set of binoculars. Anything I can do?

I have some dawn sighting opportunities in the days ahead
which I intend to work diligently.

Observe for nearby objects leading or trailing.

Observe for light fluctuations, both periodic and occasional.

Observe for indications of propellant leak.

The lack of tumbling would be very interesting.  If the spacecraft can hold a stable attitude, then that implies the attitude control system must be working and therefore at least the attitude control portion of the data processing system and the power system.  Of course if it were tumbling and powered then communications should be possible (although intermittent) no matter what the orientation of the antennas - eventually the antennas will tumble into view.

Should be an interesting observation, if the weather permits.

Andy


Offline just-nick

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #667 on: 11/10/2011 10:13 PM »
If a 10+ meter dishes on the ground with many kw of transmit power can't do it, it's extremely unlikely that some dinky radio on a spacecraft would do better, even if it were theoretically possible.

I was under the impression that the problem was line-of-sight.
If the problem is that the line of sight is blocked (e.g. some bit of tank structure is in the way) as opposed to the spacecraft/antenna facing in an unexpected direction, then no amount of trying different angles and positions may be enough to get through.

--N

Offline Svetoslav

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #668 on: 11/10/2011 10:14 PM »
As far as I understand, they are running out of their silver bullets and over the next few hours we will know if they've taken all measures to contact the spacecraft.

Offline joek

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #669 on: 11/10/2011 10:17 PM »
A bit OT, but IIRC  Goldstone is capable of pushing >400KW (or was); not sure about other DSN 70-meter sites.  Raw power would thus not appear to be the limiting factor in waking up or talking to Fobos-Grunt (assuming the Russians don't have a similar capability, ask for assist, and systems are compatible?).*

Anyone know what Chinese assist might be engaged or on the table, seeing as they also have a vested interest in the mission?

And again, kudos and appreciation to all who've kept the updates coming, and Chris et. al. who make it possible.


* DSN has some serious reach in both directions.  Goldstone was capable of getting Pioneer's attention through the omni well past the asteroid belt (and that was almost 40 years ago).

Online daver

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #670 on: 11/10/2011 10:21 PM »
Thanks Hop.   ;)

Thanks Prober. Awesome!  Couldn't figure out how to get more than one on the screen at the same time.  So, just pulled up two different sites.   :)

Thanks Robo(chris) for fixing the link.  ;D

Offline Satori

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #671 on: 11/10/2011 10:24 PM »
So are we all on side with the reports that we'll know one way or the other over the next few hours?

Yes, it looks like...

Offline simonbp

DSN has some serious reach in both directions.  Goldstone was capable of getting Pioneer's attention through the omni well past the asteroid belt (and that was almost 40 years ago).

I know someone doing radar studies of Europa with the Goldstone 70-m. So yes, lots of power.

Online daver

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #673 on: 11/10/2011 10:28 PM »
If a 10+ meter dishes on the ground with many kw of transmit power can't do it, it's extremely unlikely that some dinky radio on a spacecraft would do better, even if it were theoretically possible.

I was under the impression that the problem was line-of-sight.  With a clear shot at the antenna, you wouldn't need more power than the ground station, or (most likely) even as much.

That's what I was thinking.  More of a sniper shot vrs. a bombing run. :)

Offline Nickolai

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #674 on: 11/10/2011 10:36 PM »
So are we all on side with the reports that we'll know one way or the other over the next few hours?

Not sure what you mean by "on side." If I were on this project I wouldn't leave the console until the thing either worked or re-entered. Far too much is at stake to simply give up.

Do they know the orientation of Phobos-Grunt? Would that information be helpful?

The last known orientation was facing the Sun with solar panels deployed. But since it's not transmitting telemetry anymore, it's not possible to say definitively what orientation it's in without looking at it.

If it were still facing the Sun, then it's probably still getting power to charge the batteries which means they're not a limiting factor in trying to contact the probe (earlier reports suggested the craft can last for 3 days on battery power). So they could keep trying and know it wouldn't be 100% pointless since there's something on there with power. And the fact that it's able to keep a stable orientation would imply a lot of the systems are in fact working.

Offline Robotbeat

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #675 on: 11/10/2011 10:38 PM »
So amateur observations of the probe would be helpful, maybe observations from ISS if there are any more close passes? (There was an observation earlier from ISS.)
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Offline ChileVerde

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #676 on: 11/10/2011 10:39 PM »
I know someone doing radar studies of Europa with the Goldstone 70-m. So yes, lots of power.

Slightly off-thread, but do you have a reference/URL for that?  I like to keep up with long-range radar capabilites.
"I canít tell you which asteroid, but there will be one in 2025," Bolden asserted.

Online hop

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #677 on: 11/10/2011 10:41 PM »
If the problem is that the line of sight is blocked (e.g. some bit of tank structure is in the way) as opposed to the spacecraft/antenna facing in an unexpected direction, then no amount of trying different angles and positions may be enough to get through.
Maybe, but even if Fobos Grunt is in a consistent orientation on each pass, ground stations will see it from a pretty wide range of angles.

A spacecraft whizzing by in a different orbit is unlikely to do much better, and it seems pretty implausible that one which wasn't intended for this could be configured to do it on short notice.

Limited com opportunities is a real issue, especially given the reports that only Baikonur can uplink, but a more plausible solution to that would be to use additional ground stations (e.g. DSN, ESA...)

Offline sdsds

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #678 on: 11/10/2011 10:52 PM »
Goldstone is capable of pushing >400KW (or was)

Combine this insight about Goldstone's capability with Anatoly Zak's comments (repeating "some unofficial reports") that a signal from the ground can command FG to transmit signals "for radio-measurements of its trajectory," and that this command is sent directly to the FG transmitter, "bypassing other systems."

Presumably that command is short and could thus be repeated many times during a single pass over Goldstone, so even a tumbling spacecraft might receive it once.  And it would only need to be successfully received and acted upon once to get back "I'm alive!" confirmation.  It is difficult to believe the Russians would be unwilling to ask for this in the present situation.  So I hope the reports that the Russians might give it up for dead sometime soon are ... inaccurate.
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Offline Rocket Science

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Re: LIVE: Zenit-2SB launch with Phobos-Grunt - November 8, 2011
« Reply #679 on: 11/10/2011 10:53 PM »
I donít see it as a choice of power vs. precision, whatever assets you have, try it. In the mean time better have a plan for entry and donít wait too long or let pride get in the wayÖ
"The laws of physics are unforgiving"
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