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#160
by
strawwalker
on 08 Nov, 2022 10:49
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I watched the launch naked eye and the backlit exhaust definitely appeared to change direction immediately after stage 2 ignition. I wasn't watching the webcast and didn't understand at the time why it looked the way it did.
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#161
by
LH2NHI
on 08 Nov, 2022 14:06
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The second-stage coasting attitude anomaly and its return is probably not just a display anomaly, but an actual attitude change.
At the time of the second stage ignition, the perigee altitude dropped from -5212km to -5226km, and after recovering its attitude, it started to rise again.
https://twitter.com/NASASpaceflight/status/1589568139372920832?s=20&t=8cyRwBkySO_o6HQIMpJT1QIt seems more likely that the apparent flipping at S2 startup was a visualization glitch rather than the actual movement of the stage.
Could the stage actually rotate that way roughly around its axis with the engine running? If it was really facing the wrong way and if GNC can really recover from that, wouldn't it require a rather large circle to turn around?
The Castor 30XL is electromechanically gimballed, so yes, and is capable of much more control authority than the RCS.
The visualization shows the stack always centered around its CoM, so you won't see translations, just rotations, no matter what movements it's actually performing. That's why you see the first stage "falling away" although in reality it's moving at mostly the same speed in a similar trajectory to the still unfired second stage, having received just a small push "backwards". The viewpoint isn't a camera centered on the predicted instantaneous point of flight, showing the stack in its actual 3D position. In fact, the visualization does not use "expected" predictions at all. In inertial space, the apparent movement would of course be quite different.
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#162
by
edkyle99
on 08 Nov, 2022 15:56
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The second-stage coasting attitude anomaly and its return is probably not just a display anomaly, but an actual attitude change.
At the time of the second stage ignition, the perigee altitude dropped from -5212km to -5226km, and after recovering its attitude, it started to rise again.
Agreed. This only leaves the question of whether this was supposed to happen or not. We did see RCS firings on the graphic during the pre-start rotation, which would seem to indicate a purposeful rotation. Then again, maybe the RCS was fighting unexpected tip-off forces that could not be overcome until the Castor 30XL motor started. The thrusters appeared to be trying to orient the stage along the velocity vector, but without effect. (Could the stage have hung up on the first stage? Unseparated cable connector, etc.?)
My guess is that Northrop will say it wasn't planned, that something unexpected occurred, but that the system responded as designed, etc. Only a guess.
- Ed Kyle
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#163
by
FutureSpaceTourist
on 08 Nov, 2022 16:55
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#164
by
punder
on 08 Nov, 2022 17:45
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The fairings departed during the attitude excursion. Looks like the RCS stopped firing at the moment of separation but resumed immediately with the fairings still close to the spacecraft (in the animation at least). Maybe there was contact between a fairing and the solar array?
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#165
by
Targeteer
on 08 Nov, 2022 18:07
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From the DPC, the solar array is still not deployed. All powered payloads have been turned off. Managers are examining approach options in the current state.
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#166
by
sdsds
on 08 Nov, 2022 19:18
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Somewhat hypothetical topics for discussion: does the event necessitate a stand-down of Antares/Cygnus as an investigation is conducted? And somewhat specifically for @edkyle99
, if an event during ascent damages a payload, does that make it a launch failure?
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#167
by
jimvela
on 08 Nov, 2022 19:54
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On the nominal timeline, wasn't the NG-18 arrival at ISS expected at around 06:00 Eastern time tomorrow morning ( 9 November)?
If there are modified approach options or timelines this should be very apparent as the day goes by.
Does it seem a bit unusual that more hasn't been released about the launch event and the state of the Cygnus?
If powered payloads have been turned off, doesn't it seem likely that there is at least some loss of science that can be expected ? (e.g. don't the life sciences payloads require power to ensure the viability of the experiments?)
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#168
by
whitelancer64
on 08 Nov, 2022 20:05
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Somewhat hypothetical topics for discussion: does the event necessitate a stand-down of Antares/Cygnus as an investigation is conducted? And somewhat specifically for @edkyle99 , if an event during ascent damages a payload, does that make it a launch failure?
If the launch vehicle caused the failure, then there should be no
Cygnus stand-down .... if, for example, as supposed above, the upper stage or fairing did not properly separate and something contacted the Cygnus and damaged the solar array, that would clearly be a LV issue.
Anyway, this was the penultimate launch of the Antares 230. The next 3 Cygnus launches after that are all going up on the Falcon 9 and then they roll out the Antares 330 late in 2024. Any needed LV fixes should roll into the 330. If something went horribly wrong with the 230 maybe they'd just option in the Falcon 9 one flight sooner.
However, the payload isn't lost, one solar array aside, it is otherwise functional, and they are evaluating options for getting it to the ISS, so we can't call it outright failure either.
At best it is a potential partial failure and we don't know enough about the failure or its causes to say much more.
Which is also why we haven't had much in the way of updates. They probably don't know enough to make a public statement yet.
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#169
by
Jim
on 08 Nov, 2022 20:49
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On the nominal timeline, wasn't the NG-18 arrival at ISS expected at around 06:00 Eastern time tomorrow morning ( 9 November)?
If there are modified approach options or timelines this should be very apparent as the day goes by.
Does it seem a bit unusual that more hasn't been released about the launch event and the state of the Cygnus?
If powered payloads have been turned off, doesn't it seem likely that there is at least some loss of science that can be expected ? (e.g. don't the life sciences payloads require power to ensure the viability of the experiments?)
And food refrigerators/freezers
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#170
by
sdsds
on 08 Nov, 2022 22:17
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Regarding non-powered payloads:
On Tuesday, Nov. 15, NASA astronauts Josh Cassada and Frank Rubio will exit the station’s Quest airlock to assemble a mounting bracket on the starboard side of the station’s truss assembly. [...] The bracket and other hardware for the spacewalk is targeted to launch Sunday, Nov. 6, on the agency’s next Northrop Grumman Cygnus commercial resupply mission.
So the EVA is dependent on successful NG-18 docking?
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#171
by
dsmillman
on 08 Nov, 2022 22:23
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Regarding non-powered payloads:
On Tuesday, Nov. 15, NASA astronauts Josh Cassada and Frank Rubio will exit the station’s Quest airlock to assemble a mounting bracket on the starboard side of the station’s truss assembly. [...] The bracket and other hardware for the spacewalk is targeted to launch Sunday, Nov. 6, on the agency’s next Northrop Grumman Cygnus commercial resupply mission.
So the EVA is dependent on successful NG-18 docking?
Yes. The mounting bracket is coming up on the Cygnus.
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#172
by
FutureSpaceTourist
on 08 Nov, 2022 22:32
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https://twitter.com/nasaspaceflight/status/1590125043241340929Cygnus NG-18 will arrive at the ISS with just one of its solar arrays deployed. Cygnus has sufficient power to rendezvous.
The Northrop Grumman Cygnus cargo spacecraft has successfully deployed one of its two solar arrays and completed four rendezvous burns on its way to the International Space Station.
To remain focused on the spacecraft's arrival at the station, Northrop Grumman and NASA made the determination not to deploy the second solar array after initial attempts to deploy it were unsuccessful.
The Cygnus team is gathering information on why the second array did not deploy as planned. Cygnus has sufficient power to rendezvous with the space station Wednesday, Nov. 9. Northrop Grumman is working closely with NASA to monitor and assess the spacecraft ahead of tomorrow's planned arrival, capture, and installation at the space station.
Mission teams also are planning additional inspections of the cargo spacecraft during approach and after capture.
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#173
by
Skyrocket
on 08 Nov, 2022 22:58
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Somewhat hypothetical topics for discussion: does the event necessitate a stand-down of Antares/Cygnus as an investigation is conducted? And somewhat specifically for @edkyle99 , if an event during ascent damages a payload, does that make it a launch failure?
If the launch vehicle caused the failure, then there should be no Cygnus stand-down .... if, for example, as supposed above, the upper stage or fairing did not properly separate and something contacted the Cygnus and damaged the solar array, that would clearly be a LV issue.
Anyway, this was the penultimate launch of the Antares 230. The next 3 Cygnus launches after that are all going up on the Falcon 9 and then they roll out the Antares 330 late in 2024. Any needed LV fixes should roll into the 330. If something went horribly wrong with the 230 maybe they'd just option in the Falcon 9 one flight sooner.
However, the payload isn't lost, one solar array aside, it is otherwise functional, and they are evaluating options for getting it to the ISS, so we can't call it outright failure either.
At best it is a potential partial failure and we don't know enough about the failure or its causes to say much more.
Which is also why we haven't had much in the way of updates. They probably don't know enough to make a public statement yet.
The success of a launch is not expressed by a binary value. There are a lot of shades of gray between a complete success and a complete failure.
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#174
by
edkyle99
on 08 Nov, 2022 23:08
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Somewhat hypothetical topics for discussion: does the event necessitate a stand-down of Antares/Cygnus as an investigation is conducted? And somewhat specifically for @edkyle99 , if an event during ascent damages a payload, does that make it a launch failure?
In this case, the launch vehicle put the payload where it was supposed to go. We don't know enough about the solar panel situation to know if the payload
was damaged. Another similar panel had problems opening on another, non-Cygnus mission (Lucy). That panel eventually did open almost fully I believe. It might just be something about the panel design that hasn't been completely sorted out.
- Ed Kyle
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#175
by
Rondaz
on 08 Nov, 2022 23:18
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Cygnus Prepares for Rendezvous with Space Station
Heidi Lavelle Posted on November 8, 2022
The Northrop Grumman Cygnus cargo spacecraft has successfully deployed one of its two solar arrays and completed four rendezvous burns on its way to the International Space Station. To remain focused on the spacecraft’s arrival at the station, Northrop Grumman and NASA made the determination not to deploy the second solar array after initial attempts to deploy it were unsuccessful. The Cygnus team is gathering information on why the second array did not deploy as planned. Cygnus has sufficient power to rendezvous with the space station Wednesday, Nov. 9. Northrop Grumman is working closely with NASA to monitor and assess the spacecraft ahead of tomorrow’s planned arrival, capture, and installation at the space station. Mission teams also are planning additional inspections of the cargo spacecraft during approach and after capture.
NASA TV coverage of rendezvous and capture will begin at 3:30 a.m. EST followed by installation coverage at 7:15 a.m. At about 5:05 a.m., Expedition 68 NASA astronaut Nicole Mann will capture Cygnus with the station’s robotic arm, with NASA astronaut Josh Cassada acting as backup. After Cygnus capture, ground commands will be sent from mission control at NASA’s Johnson Space Center in Houston for the station’s arm to rotate and install it on the station’s Unity module Earth-facing port.
https://blogs.nasa.gov/ng-crs-18/2022/11/08/cygnus-prepares-for-rendezvous-with-space-station/
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#176
by
Rondaz
on 09 Nov, 2022 00:19
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#177
by
Targeteer
on 09 Nov, 2022 06:33
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From the DPC, Cygnus capture on track, 11 km out. Additional photos after capture requested, details to follow.
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#178
by
centaurinasa
on 09 Nov, 2022 07:34
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#179
by
centaurinasa
on 09 Nov, 2022 07:37
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Except SA deployment, all nominal aboard Cygnus spaceship.
, if an event during ascent damages a payload, does that make it a launch failure?