6 ms·

ISS loses attitude control after Nauka module docking

145 points by NewLogic 5y ago

geocrasher 5y ago
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 https://www.youtube.com/watch?v=fDp8jbP_22c
- jandrese 5y ago
  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 5y ago
    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.
    - ithinkso 5y ago
      I love the fact that 'at night' is still a correct term but it's only 45 min for ISS.
- xoa 5y ago
  >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 https://www.spaceacademy.net.au/watch/debris/orblife.htm 1: https://old.reddit.com/r/space/comments/ld4vlq/gabbard_diagram_animation_of_space_debris_since/ https://old.reddit.com/r/space/comments/ld4vlq/gabbard_diagr...
deleted 5y ago
[deleted]
NewLogic 5y ago
Being reported as a flight computer state machine fault. https://twitter.com/NASASpaceflight/status/1420804282685792261 https://twitter.com/NASASpaceflight/status/14208042826857922...
jarym 5y ago
attitude control huh?
- na85 5y ago
  Yes, "attitude" is an aerospace industry term for "the way you are pointing/oriented".
  - unstatusthequo 5y ago
    So like heading, course, angle, direction, vector, and other terms that make more sense?
    - pksebben 5y ago
      those all have distinct but specific meanings. Attitude refers to a collection of those terms, specifically as they relate to the frame of reference (the ground, in nearly all cases) https://aviation.stackexchange.com/questions/35933/what-is-the-exact-meaning-of-attitude-does-it-include-translational-movement/35935#35935 https://aviation.stackexchange.com/questions/35933/what-is-t...
    - na85 5y ago
      I mean "attitude" makes perfect sense to those of us who actually work in aerospace. It's related to all the terms you listed but none of them are strictly equivalent. But go ahead and be snarky if it makes you feel better?
- snypher 5y ago
  https://en.wikipedia.org/wiki/Attitude_control https://en.wikipedia.org/wiki/Attitude_control
- deleted 5y ago
  [deleted]
- CamperBob2 5y ago
  As in many other areas of life, your attitude determines your altitude!
katerberg 5y ago
Seems like they're out of the immediate problem area: https://twitter.com/SciGuySpace/status/1420798716554928132 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 5y ago
  I wonder how much fuel was lost as a result of this.
LeoPanthera 5y ago
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 https://video.ibm.com/channel/live-iss-stream (Currently no video, intermittent audio.)
- Medox 5y ago
  I hope NASA will team up with Starlink for providing multiple 24-7 live streams. At least full hd please.
- mrpippy 5y ago
  IBM bought Ustream a few years ago and it’s now rebranded as IBM Cloud Video
  - denkmoon 5y ago
    As an IBM employee, my condolences to anyone who relied on ustream.
  - qwertox 5y ago
    `nslookup` shows that the IP addresses for ustream.tv and video.ibm.com are the same ones. I also recall looking at ISS live streams on ustream.tv a couple of years ago.
- FreshFries 5y ago
  THANKS! Never knew a livestream existed and now I'm clued to my headset.
- TimGremalm 5y ago
  Spacedashboard have a nice summary of the streams and the position over earth. https://spacedashboard.com/ https://spacedashboard.com/
egberts 5y ago
Attitude?! Why I never … It’s all about the orientation, #headduck
- mrlonglong 5y ago
  Where's Attitude Adjuster when one's needed ...
  - CompuHacker 5y ago
    It's alright, those NASA boys have got the Steely Glint in their eyes.
    - mrlonglong 5y ago
      GCU Funny, It Worked Last Time is on its way.
nraynaud 5y ago
for people curious, when that website is not broken https://www.internationaldockingstandard.com/download/IDSS_IDD_Revision_E_TAGGED.pdf 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.
jfengel 5y ago
Well, fix the fucking thing! (I have been waiting decades to make that joke.)
- dylan604 5y ago
  Was it everything you hoped it would be?
  - jfengel 5y ago
    Yeah, actually. Worth it.
kiryin 5y ago
attitude control, yeah, we've all had one of those days.

145 points by NewLogic 5y ago

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 https://www.youtube.com/watch?v=fDp8jbP_22c

jandrese 5y ago
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 5y ago
  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.
  - ithinkso 5y ago
    I love the fact that 'at night' is still a correct term but it's only 45 min for ISS.
xoa 5y ago
>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 https://www.spaceacademy.net.au/watch/debris/orblife.htm 1: https://old.reddit.com/r/space/comments/ld4vlq/gabbard_diagram_animation_of_space_debris_since/ https://old.reddit.com/r/space/comments/ld4vlq/gabbard_diagr...

deleted 5y ago

[deleted]

NewLogic 5y ago

Being reported as a flight computer state machine fault. https://twitter.com/NASASpaceflight/status/1420804282685792261 https://twitter.com/NASASpaceflight/status/14208042826857922...

jarym 5y ago

attitude control huh?

na85 5y ago
Yes, "attitude" is an aerospace industry term for "the way you are pointing/oriented".
- unstatusthequo 5y ago
  So like heading, course, angle, direction, vector, and other terms that make more sense?
  - pksebben 5y ago
    those all have distinct but specific meanings. Attitude refers to a collection of those terms, specifically as they relate to the frame of reference (the ground, in nearly all cases) https://aviation.stackexchange.com/questions/35933/what-is-the-exact-meaning-of-attitude-does-it-include-translational-movement/35935#35935 https://aviation.stackexchange.com/questions/35933/what-is-t...
  - na85 5y ago
    I mean "attitude" makes perfect sense to those of us who actually work in aerospace. It's related to all the terms you listed but none of them are strictly equivalent. But go ahead and be snarky if it makes you feel better?
snypher 5y ago
https://en.wikipedia.org/wiki/Attitude_control https://en.wikipedia.org/wiki/Attitude_control
deleted 5y ago
[deleted]
CamperBob2 5y ago
As in many other areas of life, your attitude determines your altitude!

katerberg 5y ago

Seems like they're out of the immediate problem area: https://twitter.com/SciGuySpace/status/1420798716554928132 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 5y ago
I wonder how much fuel was lost as a result of this.

LeoPanthera 5y ago

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 https://video.ibm.com/channel/live-iss-stream (Currently no video, intermittent audio.)

Medox 5y ago
I hope NASA will team up with Starlink for providing multiple 24-7 live streams. At least full hd please.
mrpippy 5y ago
IBM bought Ustream a few years ago and it’s now rebranded as IBM Cloud Video
- denkmoon 5y ago
  As an IBM employee, my condolences to anyone who relied on ustream.
- qwertox 5y ago
  `nslookup` shows that the IP addresses for ustream.tv and video.ibm.com are the same ones. I also recall looking at ISS live streams on ustream.tv a couple of years ago.
FreshFries 5y ago
THANKS! Never knew a livestream existed and now I'm clued to my headset.
TimGremalm 5y ago
Spacedashboard have a nice summary of the streams and the position over earth. https://spacedashboard.com/ https://spacedashboard.com/

egberts 5y ago

Attitude?! Why I never … It’s all about the orientation, #headduck

mrlonglong 5y ago
Where's Attitude Adjuster when one's needed ...
- CompuHacker 5y ago
  It's alright, those NASA boys have got the Steely Glint in their eyes.
  - mrlonglong 5y ago
    GCU Funny, It Worked Last Time is on its way.

nraynaud 5y ago

for people curious, when that website is not broken https://www.internationaldockingstandard.com/download/IDSS_IDD_Revision_E_TAGGED.pdf 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.

jfengel 5y ago

Well, fix the fucking thing! (I have been waiting decades to make that joke.)

dylan604 5y ago
Was it everything you hoped it would be?
- jfengel 5y ago
  Yeah, actually. Worth it.

kiryin 5y ago

attitude control, yeah, we've all had one of those days.