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#120
by
Galactic Penguin SST
on 25 Apr, 2013 13:39
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According to NK forum EVA might be needed as this antenna might interfere with achieving hard dock (capture is still possible and in fact this is likely what would happen). Someone is proposing to use crowbar to tear this antenna apart 
There are also mentioned that things like that had happened in the past.
If so that would be kinda cool to watch (I hope there will be coverage)
What's wrong with using Dextre? I mean, this is a perfect opportunity to try something like this and avoid an EVA.
On the end of Zvezda? That's probably very far from the closest PGDF that I doubt this could be possible.
Russian sources are claiming that an EVA will not be required, but reports on L2 seems to refute that....
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#121
by
asmi
on 25 Apr, 2013 13:41
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Russian sources are claiming that an EVA will not be required, but reports on L2 seems to refute that....
Yea my research turned up contradicting assessments of the situation, so I guess let's wait for more details. Still such a EVA would be cool!
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#122
by
robertross
on 25 Apr, 2013 14:40
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What's wrong with using Dextre? I mean, this is a perfect opportunity to try something like this and avoid an EVA.
I don't know. As far as I understand "soft-docked" Soyuz/Progress basically hangs on the probe and can sway around (I recall some docking videos which see quite a movement after soft-dock). Which could make robotics op quite dangerous if it sways wrong way duing op.
Well, Dextre has 2 hands, and is designed to stabilize itself against something (Progress in this case).
I do have doubts now about reach...probably is too far.
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#123
by
Danderman
on 25 Apr, 2013 14:41
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If the antenna is stuck in its undeployed position, that indicates a pyro bolt that has not blown. There may also be a backup bolt that has not blown, indicating a total system failure for deployment.
There is a second pyro system, which is used in the final stages of docking to "push" the antenna cone away from the front of Progress, and which may be tried tomorrow, but if the entire system is shot, it probably won't activate.
As for Progress docking locations accessible to Dexter, Zvezda rear is too far, Rassvet is good, and the Pirs/Poisk docking locations are marginally accessible.
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#124
by
JimO
on 25 Apr, 2013 15:14
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Daily ISS update just mentioned ongoing discussions, showed a close-out photo of the antenna boom on the Progress, but no real news.
Is it time for a space history geek to list all the post-docking EVAs needed to complete docking missions? I can't get to it myself, alas.
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#125
by
Danderman
on 25 Apr, 2013 15:22
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Daily ISS update just mentioned ongoing discussions, showed a close-out photo of the antenna boom on the Progress, but no real news.
Is it time for a space history geek to list all the post-docking EVAs needed to complete docking missions? I can't get to it myself, alas.
I do not believe that Progress or ISS flight rules would allow a Progress to hang off a docking port in soft dock mode for more than a few minutes, so an EVA or RMS ops are unlikely. Also, the multiple undeployed pyro bolts make this risky for EVA.
I would not rule out a decision to simply fire the thrusters after soft dock to bend the antenna back and allow hard dock.
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#126
by
Targeteer
on 25 Apr, 2013 15:29
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Daily ISS update just mentioned ongoing discussions, showed a close-out photo of the antenna boom on the Progress, but no real news.
Is it time for a space history geek to list all the post-docking EVAs needed to complete docking missions? I can't get to it myself, alas.
Discussions on the Russian net about a Radiogram indicate confusion by the crew because Moscow indicated an automated approach but the crew is being told to review the Radiogram--indicating a non-automated approach. The required "specialists" are not immediately available--a fairly common occurrence from listening to the ISS feed. There was no mention of the specific technical issue.
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#127
by
JimO
on 25 Apr, 2013 15:31
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1528 gmt -- media interviews, antenna question -- Marshburn: "that's the story as we've got it".... "we've got backup plans , spacewalk is one of the backup plans plans, that's right."
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#128
by
Targeteer
on 25 Apr, 2013 15:36
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Moscow just confirmed to the crew an automated approach is planned with monitoring at 1500 and 400 meters and no planned changes to the normal plan.
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#129
by
Targeteer
on 25 Apr, 2013 15:45
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Moscow just passed that a meeting about the issue is ongoing which is why details the crew wants on the plan are unavailable. The crew is free to call someone (missed the name) in about 2 hours--presumably via the IP phone.
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#130
by
Danderman
on 25 Apr, 2013 15:53
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I should mention that if the cone of the antenna obscures the docking collar, then there would be real problems.
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#131
by
Danderman
on 25 Apr, 2013 15:56
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Also, for those who do not these missions closely, the Progress only passes over Russian ground stations for about a third of the orbits each day, and then for a maximum of 12 minutes per pass. That means that time to download telemetry and upload software is limited.
Communications will get better as the Progress comes into range of ISS, as the Russian segment is now linked to the ground via TDRS.
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#132
by
asmi
on 25 Apr, 2013 16:02
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I do not believe that Progress or ISS flight rules would allow a Progress to hang off a docking port in soft dock mode for more than a few minutes, so an EVA or RMS ops are unlikely. Also, the multiple undeployed pyro bolts make this risky for EVA.
Apparently there are no flight rules forbidding that. It has been done in the past, here is example:
http://en.wikipedia.org/wiki/Progress_M1-7 The Progress was hanging on the probe for several days.
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#133
by
Space Pete
on 25 Apr, 2013 16:07
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What's wrong with using Dextre? I mean, this is a perfect opportunity to try something like this and avoid an EVA.
Dextre would not be able to be used for this, since:
A) There would not be enough reach to get Dextre to the SM Aft location, even if the SSRMS was based from the FGB PDGF (which wouldn't be doable at this time anyway since the FGB PDGF is not yet active).
B) Although Dextre is commonly referred to as having "hands", all it really has is a grasping mechanism that is only compatible with so-called "micro fixtures" - and there aren't any of those on the Progress.
C) I doubt the robotics operators would want to place Dextre anywhere near an antenna that could suddenly spring open and cause damage.
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#134
by
Danderman
on 25 Apr, 2013 17:03
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I do not believe that Progress or ISS flight rules would allow a Progress to hang off a docking port in soft dock mode for more than a few minutes, so an EVA or RMS ops are unlikely. Also, the multiple undeployed pyro bolts make this risky for EVA.
Apparently there are no flight rules forbidding that. It has been done in the past, here is example: http://en.wikipedia.org/wiki/Progress_M1-7 The Progress was hanging on the probe for several days.
How Progress M1-7 managed to hang on to ISS until hard dock is a bit of a mystery to me. It happens that I was with Energia docking experts when this incident occurred, but I can't remember the details now, as there was mass consumption of alcohol by me immediately after hard dock. I would guess that M1-7 somehow achieved more than soft docking (ie "capture") but that electrical circuits could not be mated, due to a tiny amount of rubber in the way. In other words, that Progress M1-7 may have been structurally mated to ISS, but the interfaces were not connected.
The flight rules exist to prevent a visiting vehicle from "flopping around" when ISS is not in free drift, ie returning to a nominal attitude.
Until the docking process complete signal is given, ISS is to remain in free drift. That signal is not given until hard dock is complete.
If the Progress is only in soft dock mode, where the connection is simply the probe in the cone, the Progress would be liable to moving around during ISS attitude maneuvers. Or, if a DAM were required, things could get difficult.
IF the Kurs antenna is obscuring the docking collar and preventing the hooks and latches to engage, I don't think the flight rules are going to allow the Progress to sit there in soft dock mode for very long.
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#135
by
Prober
on 25 Apr, 2013 17:05
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Daily ISS update just mentioned ongoing discussions, showed a close-out photo of the antenna boom on the Progress, but no real news.
Is it time for a space history geek to list all the post-docking EVAs needed to complete docking missions? I can't get to it myself, alas.
I do not believe that Progress or ISS flight rules would allow a Progress to hang off a docking port in soft dock mode for more than a few minutes, so an EVA or RMS ops are unlikely. Also, the multiple undeployed pyro bolts make this risky for EVA.
I would not rule out a decision to simply fire the thrusters after soft dock to bend the antenna back and allow hard dock.
can the pyro bolts be unbolted without danger?
Seem to remember explosive bolts that needed to be replaced somewhere on the ISS like last year. Anyone remember that?
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#136
by
JimO
on 25 Apr, 2013 17:10
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Golly, if the sequester 'cuts' hurt NASA so much, why don't they just outsource the MCC functions to this forum? Dang but there are insightful, experienced, candid folks loose hereabouts. Delightful. Molodtsi, all around, y'all.
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#137
by
robertross
on 25 Apr, 2013 17:35
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Seem to remember explosive bolts that needed to be replaced somewhere on the ISS like last year. Anyone remember that?
The issue was pyro bolts on the Soyuz, based on a previous failure
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#138
by
Star One
on 25 Apr, 2013 17:48
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What is the likelihood that issue will cause any delay with future Soyuz & Progress missions to ISS?
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#139
by
Chris Bergin
on 25 Apr, 2013 17:52
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NASA:
Managers meet tonight to determine if Progress will press for docking. If approved, NASA TV coverage begins Fri@6:30a- Docking planned@8:26a
There are also mentioned that things like that had happened in the past.