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#440
by
owais.usmani
on 16 Dec, 2015 17:12
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http://www.russianspaceweb.com/iss-soyuz-tma19m.html#culpritAlthough there was no immediate official explanation for the aborted automated rendezvous between the Soyuz TMA-19M and the ISS, a commentator at the Novosti Kosmonavtiki magazine quickly narrowed down a culprit in the failure of the DPO-B No. 20 attitude-control thruster. This small engine is a part of the two independent engine clusters known as Circuit 1 and Circuit 2. Distributed around the ship's instrument module, PAO, both groups of small engines are used to fine-tune the spacecraft's orientation in space and to conduct low-thrust maneuvers. The particular engine provides a sideway thrust along -Y axis in the ship's coordinate system.
As the available video and audio footage reveals, at a distance of around 17 meters from the station, an alarm sounded in the Soyuz's cockpit, while the overlay display on the rendezvous camera showed "No SDK (combustion chamber pressure or valve signal) along -Y axis (K1B)." The K1B likely stands for Collector 1 (Circuit 1). That alarm was followed by another warning, which can be translated as "Total failure of the K1B circuit." In addition, the "A: DPOB 20" message, indicating a problem with the particular thruster and the numeric code for the failure type was also displayed.
Immediately thereafter, the Soyuz began backing away from the station still under the automated control. Malenchenko reported to mission control that the crew received the DPOB 20-type failure.
For a reason yet to be explained, the automated system apparently failed to switch to a backup circuit available just for such a contingency.
After switching to manual controls, it took the Soyuz commander two attempts to put the spacecraft into right orientation and complete the docking. During the first try, the spacecraft began a seemingly faster-than-normal approach to the station and then, suddenly, turned sideways just meters from the docking port and deviated from its approach.
Fortunately, Malenchenko quickly managed to stabilize the spacecraft, restore its alignment with docking port on the Rassvet module and complete the second manual docking attempt.
Shortly after docking, Malenchenko explained mission control that during his first manual approach attempt he could not see the docking port clear enough and only realized the problem at the last minute.
According to the Novosti Kosmonavtiki magazine, a similar problem with DPO thrusters also prevented an automated docking of the Progress M-05M cargo ship in 2010 and required the crew onboard the station to use the remote control to complete the process.
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#441
by
the_other_Doug
on 16 Dec, 2015 18:19
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You know, there was an anecdote (perhaps a myth?) out there from back in the Mir days, that the cosmonauts didn't get paid a whole lot of money -- but got "commissions" or "bonuses" for performing various procedures in flight, if they became necessary. One of these was for performing a manual docking in the event of a KURS failure.
The anecdote was that several Soyuz commanders would turn off the KURS once everything was well lined up, report a "KURS failure," manually complete the docking, and pocket their bonus for it once they got back home.
I just wanted to point out that the observed dynamics during this approach absolutely confirm that there was a thruster issue, and that, even if there was still such a bonus system in place (and I'm fairly certain there is not), this isn't a situation where Yuri pulled the fast-and-loose "Oh, we've got a KURS failure, chuckle" maneuver.
Am I right in thinking that the Soyuz can be controlled satisfactorily for separation and de-orbit maneuvering, even with this thruster issue? We're not going to see an unmanned Soyuz launch to send up a replacement for this one, are we?
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#442
by
A12
on 16 Dec, 2015 20:08
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So, was there a thruster failure AND a KURS failure, being the latter unable to keep the control ?
(switching to the backup thruster)
In any case, good for Yuri that got a chance to fly in first person the vehicle (and earn the bonus :-) )
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#443
by
Apollo-phill
on 17 Dec, 2015 19:05
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For UK readers interest, part of the Soyuz rocket that launched Tim Peake to the ISS (rocket body labelled 2015-076B ) is expected to re-enter the Earth's atmosphere and "burn up" sometime between Thursday 17th to Friday 18th December 2015.
The "best" prediction is that this will occur over North America at 23:30 GMT on Thursday but due to a 10 hour plus/minus uncertainty in these predictions re-entry might even occur over lower SW England , Celtic Sea and English Channel.
A-P
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#444
by
psloss
on 17 Dec, 2015 21:47
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#445
by
ZachS09
on 17 Dec, 2015 21:58
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That's a cool plume!
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#446
by
owais.usmani
on 18 Dec, 2015 06:13
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http://russianspaceweb.com/iss-soyuz-tma19m.html#probeAccording to veterans of the Russian space program who witnessed the failed manual docking attempt between the Soyuz TMA-19M spacecraft and the ISS, a potential disaster was narrowly avoided which is reminiscent of the nearly catastrophic collision between the Mir space station and a Progress cargo ship in
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#447
by
Space Pete
on 18 Dec, 2015 08:43
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ISS really dodged a bullet here, this could so easily have been very nasty indeed.
I remember when I was watching the docking live that I instantly thought that the closure rate was way too high during the first manual approach, and that was before the alignment was lost. My big fear at the time was that TMA-19M was going to impact the Progress on DC-1.
It certainly makes me think about the wisdom of having a vehicle docking in between two protrusions from the ISS structure (DC-1/Progress on one side, and Cygnus on the other), because it really doesn't leave much room for error in terms of lateral deviations during docking.
Perhaps in future it would be a good idea during MRM-1 dockings to close the hatches between the ISS and any vehicle on Node 1 Nadir, and also between the ISS and DC-1. That way if ever there was an impact with any of those modules/vehicles, while they would almost certainly be lost, there would be less chance of an explosive decompression of the entire ISS as a result. Not saying it eliminates the risk, just reduces it.
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#448
by
anik
on 18 Dec, 2015 10:53
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At the peak of the crisis, the flight director for the Russian segment of the ISS Vladimir Soloviev, himself a veteran of two space missions and a towering figure in the Russian space establishment, called on the crew, essentially jumping over both, the head of the on-duty team, SRP, and the chief communications officer. Although Soloviev is well known for his hands-on management style, critics charged that his involvement could place an undue sense of urgency on Malenchenko, at a time when a calm and collected response was needed. As a result, Malenchenko failed to do something he had done hundreds of times in the simulator, critics charged. Fortunately, within minutes after the near collision, Malenchenko was able to stabilize the spacecraft and complete the second manual docking attempt successfully
I do not understand what Anatoliy Zak talks here about. In the docking video we can hear that Vladimir Solovyov has told to Yuriy Malenchenko only this: "Yuriy, let's switch to the manual approaching". That is all. There are no words anymore from Solovyov during two manual docking attempts. There is no pressure from Solovyov at all, only GCTC instructor and TsUP communicator talked with Malenchenko.
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#449
by
saturnapollo
on 18 Dec, 2015 11:39
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It certainly makes me think about the wisdom of having a vehicle docking in between two protrusions from the ISS structure (DC-1/Progress on one side, and Cygnus on the other), because it really doesn't leave much room for error in terms of lateral deviations during docking.
It certainly does look tight. However if the alignment if off so much by the time you reach that point in the docking that you are in danger of impacting either, then the crew have probably left it too late to back out and not hit part of the station itself. That close in the alignment has to be so perfect that there will be plenty of room either side of the Soyuz - not sure but the thrusters have probably been inhibited at the point due to the proximity to the station.The crew should be in a position to abort the docking due to a misalignment long before they get anywhere near either vehicle (as they did in this case).
Keith
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#450
by
DMeader
on 18 Dec, 2015 17:05
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So, bottom line, was there almost a high-speed-out-of-control collision between the Soyuz and ISS or not? Russian Space Web is sure pushing it like there was.
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#451
by
Nicolas PILLET
on 19 Dec, 2015 08:47
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So, bottom line, was there almost a high-speed-out-of-control collision between the Soyuz and ISS or not?
Nothing was out of control.
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#452
by
DMeader
on 19 Dec, 2015 13:22
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So, bottom line, was there almost a high-speed-out-of-control collision between the Soyuz and ISS or not?
Nothing was out of control.
Thank you. I didn't think so.
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#453
by
Nicolas PILLET
on 19 Dec, 2015 15:45
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At any moment, Soyuz commander was able to retreat his spaceship using DPO thrusters.
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#454
by
AJA
on 19 Dec, 2015 17:18
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<...links to Soyuz docking videos..>
I came across
this tweet earlier, and went and watched the docking video to confirm... and you can indeed see the arrays fluttering!
Is this because of RCS plume impingement? Or were the arrays being rotated at that time (with the flutter being caused due to that motion)?
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#455
by
Hog
on 19 Dec, 2015 19:07
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ISS really dodged a bullet here, this could so easily have been very nasty indeed.
I remember when I was watching the docking live that I instantly thought that the closure rate was way too high during the first manual approach, and that was before the alignment was lost. My big fear at the time was that TMA-19M was going to impact the Progress on DC-1.
It certainly makes me think about the wisdom of having a vehicle docking in between two protrusions from the ISS structure (DC-1/Progress on one side, and Cygnus on the other), because it really doesn't leave much room for error in terms of lateral deviations during docking.
Perhaps in future it would be a good idea during MRM-1 dockings to close the hatches between the ISS and any vehicle on Node 1 Nadir, and also between the ISS and DC-1. That way if ever there was an impact with any of those modules/vehicles, while they would almost certainly be lost, there would be less chance of an explosive decompression of the entire ISS as a result. Not saying it eliminates the risk, just reduces it.
Rather than "dodging a bullet" I feel it illustrates the inherent risk associated with any and all docking/berthing activities and how protocol was followed to allow a re-approach and a safe/successful docking. If there was an actual collision, then I would agree with "bullet dodging", of course, depending on the outcome of said collision.
All docking and berthing operations have the potential to "easily be very nasty".
If there was the choice, I think a collision with another docked vehicle would be chosen over collision with ISS structure itself.
Uncontrolled decompression is always a risk. "Explosive Decompression" is obviously a worse case scenario resulting from collision, but the chances of explosive decompression from docking/berthing gone wrong would be small. Collision in the context of space vehicles, always results in damage- the extent of that damage can vary, from a scratch to much worse. Mir took a few hits over the years and only the June 25, 1997 collision resulted in any sort of decompression.
xxxxxxxxxxxxxxxxxx
But enough of all this collision talk, there was no bullets dodged, there wasn't even a near miss. An approach to docking was made, then rejected, tried again and successful. Sorry media folks, and doomsday types, nothing to see here.
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#456
by
zubenelgenubi
on 23 Dec, 2015 22:35
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For UK readers interest, part of the Soyuz rocket that launched Tim Peake to the ISS (rocket body labelled 2015-076B ) is expected to re-enter the Earth's atmosphere and "burn up" sometime between Thursday 17th to Friday 18th December 2015.
The "best" prediction is that this will occur over North America at 23:30 GMT on Thursday but due to a 10 hour plus/minus uncertainty in these predictions re-entry might even occur over lower SW England , Celtic Sea and English Channel.
A-P
Ted Molczan reports on Seesat-l:
Re-entry of Soyuz TMA-19M rocket body seen from Newfoundland and LabradorThe re-entry of 2015-076B / 41125 was widely observed from Newfoundland and Labrador, on 2015 Dec 17, near 20:30 UTC (17:00 local time). It was the rocket body of the recent launch of Soyuz TMA-19M. It was the model 11S510, which has an empty mass of 2410 kg.
He posts further data here:
http://www.satobs.org/seesat/Dec-2015/0112.html