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#140
by
centaurinasa
on 07 Nov, 2022 15:30
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#141
by
sts9
on 07 Nov, 2022 15:45
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https://blogs.nasa.gov/ng-crs-18/One Cygnus Solar Array Deployed So Far
FST Edit: worth quoting what the above says
One Cygnus Solar Array Deployed So Far
After launching earlier today, Nov. 7, Northrop Grumman’s Cygnus cargo spacecraft has successfully deployed one of its two solar arrays. Northrop Grumman is gathering data on the second array deployment and is working closely with NASA.
Northrop Grumman has reported to NASA that Cygnus has sufficient power to rendezvous with the International Space Station on Wednesday, Nov. 9, to complete its primary mission, and NASA is assessing this and the configuration required for capture and berthing.
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#142
by
Rondaz
on 07 Nov, 2022 17:27
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#143
by
HVM
on 07 Nov, 2022 18:04
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First Lucy's and now Cygnus circular Ultraflex array fails. Common fault or bad luck?
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#144
by
AS_501
on 07 Nov, 2022 18:05
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This may be second incident with this fan-out type of solar array, the first being with Lucy. After docking, perhaps the station arm could be used for a close inspection of that array. But way too early to tell at this point.
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#145
by
eeergo
on 07 Nov, 2022 18:17
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Wild guess at this point, but if the recovery forces after the weird maneuver during the payload jettison coast phase might have caused some trouble? Even if it was planned, those rates must have exerted some notable, sustained and apparently new torsional stress on the sep plane and surrounding areas.
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#146
by
jimvela
on 07 Nov, 2022 18:53
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First Lucy's and now Cygnus circular Ultraflex array fails. Common fault or bad luck?
(All of this is my opinion only- no analytical basis)-
Common vulnerability in a fragile system seeing unexpected loads.
As I understand it, LUCY did something different from heritage missions in that LUCY deployed both UltraFlex in parallel. I believe previous missions did the deployments as serial operations.
You learn lots of unexpected things when you deviate from heritage methods. Particularly when dealing with systems that have complicated dynamics like deploying a flexible panel with a lanyard and associated mechanical systems.
This may be second incident with this fan-out type of solar array, the first being with Lucy. After docking, perhaps the station arm could be used for a close inspection of that array. But way too early to tell at this point.
You can bet that all parties would like a close inspection.
You can also bet that NASA is having discussions right now with NG about what other systems in the Cygnus or its payloads may have been impacted by that wild excursion on launch. Perhaps even discussion about whether and when/if an approach to ISS may proceed.
Wild guess at this point, but if the recovery forces after the weird maneuver during the payload jettison coast phase might have caused some trouble? Even if it was planned, those rates must have exerted some notable, sustained and apparently new torsional stress on the sep plane and surrounding areas.
Very likely to have been a direct cause of the deployment issues.
When I saw the post in this thread about the maneuver during staging and ignition of the upper stage, I thought immediately about those UltraFlex arrays and wondered to myself if either one would deploy. (I am actually a bit surprised that they got one to deploy fully.)
Edit to add- it may be a sign that the UltraFlex array is more robust when stowed than I had thought it may be.
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#147
by
AS_501
on 07 Nov, 2022 19:01
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Unlike Lucy, NG will have almost hands-on access to this anomaly. Will they make an attempt(s) to open the array after docking? I'm assuming the array will not be needed for departure and reentry.
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#148
by
Herb Schaltegger
on 07 Nov, 2022 20:34
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Unlike Lucy, NG will have almost hands-on access to this anomaly. Will they make an attempt(s) to open the array after docking? I'm assuming the array will not be needed for departure and reentry.
I doubt it needs the second array but any operational spacecraft "ought" to have redundancy, especially when performing any kinds of maneuvering and proximity operations near another spacecraft. Assuming the deployed array is providing good current and voltage, and the Cygnus battery system remains healthy, one array is probably all that's required for departure and disposal burn. I admit to having not paid that much attention to Cygnus ops post-separation. Anyone know off-hand about how long Cygnus free-flies until burn-up?
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#149
by
AmigaClone
on 07 Nov, 2022 21:09
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Unlike Lucy, NG will have almost hands-on access to this anomaly. Will they make an attempt(s) to open the array after docking? I'm assuming the array will not be needed for departure and reentry.
I doubt it needs the second array but any operational spacecraft "ought" to have redundancy, especially when performing any kinds of maneuvering and proximity operations near another spacecraft. Assuming the deployed array is providing good current and voltage, and the Cygnus battery system remains healthy, one array is probably all that's required for departure and disposal burn. I admit to having not paid that much attention to Cygnus ops post-separation. Anyone know off-hand about how long Cygnus free-flies until burn-up?
I took a quick look and it appears that Cygnus has deorbited as little as 24 hours after unberthing. The longest time as a free-flyer was around 25 days before deorbiting.
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#150
by
edkyle99
on 07 Nov, 2022 21:57
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The graphic during ascent appeared to show ACS thruster firings after staging but before the fairing adapter separated. Stage 2 uses cold gas thrusters. I doubt they are designed to fire before the adapter separates, but I'm not certain. (The User's Guide does say that Stage 2 ACS works during Stage 1/2 coast.) Anyone know?
- Ed Kyle
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#151
by
starbase
on 07 Nov, 2022 22:10
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The graphic during ascent appeared to show ACS thruster firings after staging but before the fairing adapter separated. Stage 2 uses cold gas thrusters. I doubt they are designed to fire before the adapter separates, but I'm not certain. (The User's Guide does say that Stage 2 ACS works during Stage 1/2 coast.) Anyone know?
- Ed Kyle
There are also RCS thrusters firing before fairing and adapter separation during the NG-17 launch (after 30m30s), so I guess that's nominal. The back flip maneuver has not happened on previous missions though.
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#152
by
Rondaz
on 08 Nov, 2022 00:01
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#153
by
Rondaz
on 08 Nov, 2022 00:01
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#154
by
FutureSpaceTourist
on 08 Nov, 2022 02:00
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#155
by
Jrcraft
on 08 Nov, 2022 02:06
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Unlike Lucy, NG will have almost hands-on access to this anomaly. Will they make an attempt(s) to open the array after docking? I'm assuming the array will not be needed for departure and reentry.
I doubt it needs the second array but any operational spacecraft "ought" to have redundancy, especially when performing any kinds of maneuvering and proximity operations near another spacecraft. Assuming the deployed array is providing good current and voltage, and the Cygnus battery system remains healthy, one array is probably all that's required for departure and disposal burn. I admit to having not paid that much attention to Cygnus ops post-separation. Anyone know off-hand about how long Cygnus free-flies until burn-up?
I took a quick look and it appears that Cygnus has deorbited as little as 24 hours after unberthing. The longest time as a free-flyer was around 25 days before deorbiting.
The longest time is actually held by NG-11, which unberthed from the ISS on 6 August and deorbited on 6 December.
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#156
by
Orbiter
on 08 Nov, 2022 02:12
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That was a very violent rotation of the second stage during ignition. I really don't think that was intentional.
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#157
by
mn
on 08 Nov, 2022 04:01
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It 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?
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#158
by
SINO4894
on 08 Nov, 2022 04:29
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If u watched the telemetry carefully enough, u'll see the speed decreased ~20m/s when the Castor-30XL trying to correct its attitude after ignition. This indicates that at the start of this phase of powered flight the direction of momentum input is somehow not aligned with or even opposite to the flight direction, so the CG is correct.
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#159
by
eeergo
on 08 Nov, 2022 08:35
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It 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.