[HN Gopher] ISS loses attitude control after Nauka module docking
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ISS loses attitude control after Nauka module docking
Author : NewLogic
Score : 122 points
Date : 2021-07-29 17:38 UTC (5 hours ago)
(HTM) web link (twitter.com)
(TXT) w3m dump (twitter.com)
| katerberg wrote:
| Seems like they're out of the immediate problem area:
| https://twitter.com/SciGuySpace/status/1420798716554928132
|
| Still lots of investigation to do and probably a permanent fix
| incoming, but no big risk of them falling out of the sky right
| now.
| ohazi wrote:
| I wonder how much fuel was lost as a result of this.
| jarym wrote:
| attitude control huh?
| [deleted]
| na85 wrote:
| Yes, "attitude" is an aerospace industry term for "the way you
| are pointing/oriented".
| snypher wrote:
| https://en.wikipedia.org/wiki/Attitude_control
| CamperBob2 wrote:
| As in many other areas of life, your attitude determines your
| altitude!
| LeoPanthera wrote:
| Aside: Today I learned about the existence of "video.ibm.com"
| which seems to be where NASA now streams its live video. I'd
| never heard of it before.
|
| Live ISS stream: https://video.ibm.com/channel/live-iss-stream
| (Currently no video, intermittent audio.)
| nraynaud wrote:
| for people curious, when that website is not broken
| https://www.internationaldockingstandard.com/download/IDSS_I... ,
| there is the list of the moment of inertia of the ISS around
| various axes and the force and torque limits a docking ship as to
| respect.
| egberts wrote:
| Attitude?! Why I never ...
|
| It's all about the orientation, #headduck
| mrlonglong wrote:
| Where's Attitude Adjuster when one's needed ...
| CompuHacker wrote:
| It's alright, those NASA boys have got the Steely Glint in
| their eyes.
| NewLogic wrote:
| Being reported as a flight computer state machine fault.
| https://twitter.com/NASASpaceflight/status/14208042826857922...
| jfengel wrote:
| Well, fix the fucking thing!
|
| (I have been waiting _decades_ to make that joke.)
| dylan604 wrote:
| Was it everything you hoped it would be?
| kiryin wrote:
| attitude control, yeah, we've all had one of those days.
| geocrasher wrote:
| People might wonder why attitude control is important. First and
| foremost: power. Solar power requires that the solar arrays be
| directed toward the sun. Losing attitude control means that
| they'll lose efficiency and thus power. This isn't a big deal in
| the short run, but long term is a big deal. Surely they'll have
| this fixed before that comes into play.
|
| Aside from that, there's a lot of other smaller factors such as
| being able to orient the station to boost orbit every so often.
| Even though they're in Low Earth Orbit, there is a _just_ enough
| atmosphere to cause the orbit to decay slightly over time, and
| this has to be compensated for by boosting the orbit. No attitude
| control = no orienting thrusters.
|
| Obligatory Scott Manley video that's way better than what I just
| said: https://www.youtube.com/watch?v=fDp8jbP_22c
| xoa wrote:
| > _Even though they 're in Low Earth Orbit, there is a just
| enough atmosphere to cause the orbit to decay slightly over
| time, and this has to be compensated for by boosting the orbit_
|
| Just to expand on this a little (since it's gaining new
| relevance with the lower LEO and VLEO large constellations
| getting planned/launched), orbital life times drop non-linearly
| with altitude, atmospheric drags plays a big role fast until
| hundreds of km above the Karman line. An oldie and simplified
| but goodie site here [0] gives a decent basic overview.
| Remember that this will also vary, the atmosphere is affected
| by temperature and other factors.
|
| Particularly since the ISS is manned and mass was very
| restricted, its altitude is a tight balancing act between high
| enough to not need to boost too often for comfort/practicality
| and as low as possible to reduce radiation exposure and stay
| away from the inner Van Allen radiation belt, which can get
| quite low indeed on occasion based on solar activity and
| geographic areas. It does mean though that ISS reboosts have to
| happen fairly regularly.
|
| One big area of current interest this has an impact on is
| orbital debris lifetimes. There's an excellent Gabbard diagram
| animation [1] on Reddit that's worth a look if you haven't seen
| it before. You can see the decay rate very visually. Having
| constellations be very low is valuable for passive fail-safety
| in case of loss of control or collisions.
|
| ----
|
| 0: https://www.spaceacademy.net.au/watch/debris/orblife.htm
|
| 1:
| https://old.reddit.com/r/space/comments/ld4vlq/gabbard_diagr...
| jandrese wrote:
| Perhaps more important than keeping the solar arrays pointed at
| the sun is keeping the radiators out of direct sunlight. The
| problem in space isn't so much freezing as cooking because
| there is no atmosphere between you and the sun and the only way
| to vent heat is inefficiently as radiation.
|
| If the radiators started cooking in direct sunlight the station
| would get uncomfortably hot in a hurry.
| ericbarrett wrote:
| I believe the ISS also orients its solar panels edge-on to
| prograde (direction of orbit) at night to minimize drag, so
| that's another consideration of attitude control failure.
| Still second order to the radiators, though.
| [deleted]
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(page generated 2021-07-29 23:01 UTC)