4 ms·

My understanding of this vehicle is that it can physically navigate in space. With stop and go functionality.

rkangel 7y ago
Any satellite can physically navigate in space, the question is how much for how long. Everything is in orbit, navigation is a question of adjusting orbits, which is a question of fuel. I don't know about 'stop and go' though, that's usually called 'takeoff and landing'.
- sandworm101 7y ago
  >> Any satellite can physically navigate in space, Not cubesats. You need some sort of an engine and an orientation mechanism. You can forgo the engine if you only want to play around with drag via orientation, but the average cube/nano sat moves, falls, along the same path as any other bit of metal up there.
  - dylan604 7y ago
    So cubesats are designed to only be in orbit for a short time? Even at LEO, without correction burns, things eventually re-enter the atmosphere. I guess it’s a feature, not a bug?
    - TeMPOraL 7y ago
      It is a feature. It ensures they don't litter orbits forever.
    - Rebelgecko 7y ago
      Many cubesats have engines, and even those that don't can use their reaction wheels to do small maneuvers by changing their orientation which causes drag to change the orbit. There are other methods to deorbit like tethers, but due to reliability they're not used often
na85 7y ago
I think your understanding might be incomplete. To "stop" in space, relative to a viewer on the ground, means going into geostationary orbit. Or, I suppose, to a Lagrange point. To borrow an XKCD-ism, space isn't high so much as it's fast. You have to go very very fast to stay in orbit, and if you were to attempt to slow down and stop whilst orbiting, you'd essentially be executing a de-orbit burn and would find yourself re-entering the atmosphere.
diydsp 7y ago
any idea why it seems the thruster is offside? [0] Doesn't that complicate mobility/control? [0]https://en.wikipedia.org/wiki/Boeing_X-37#/media/File:X_37B_OTV-2_02.jpg https://en.wikipedia.org/wiki/Boeing_X-37#/media/File:X_37B_...
- jonathankoren 7y ago
  I don’t think anyone here has the knowledge to say. You’d normally want the thrust vector to pass through the center of mass. Maybe on orbit it hangs stuff off the starboard side.
- m0zg 7y ago
  Don't know why it's offset (probably just "form over function", it doesn't need to look pretty), but it's likely no big deal. Those thrusters are gimbaled anyway, it can point wherever you want, and is typically adjusted in realtime. https://www.youtube.com/watch?v=7Wtg_3Y4lFc https://www.youtube.com/watch?v=7Wtg_3Y4lFc
- wongarsu 7y ago
  Probably to fit something else there. The thruster can gimbal/pivot, and the software already has to measure the current center of mass of the vehicle because payloads etc affect it enough to make you go in circles. So accounting for an offset thruster might not even be a software change since it's a parameter the software already has to find automatically. Also note how the main engines of the space shuttles are really far offset at launch and fire at a weird angle to compensate.
- baybal2 7y ago
  It means that its centre of mass is significantly shifted, and that is likely mandated that it was built specifically to carry that payload.

Any satellite can physically navigate in space, the question is how much for how long. Everything is in orbit, navigation is a question of adjusting orbits, which is a question of fuel. I don't know about 'stop and go' though, that's usually called 'takeoff and landing'.

sandworm101 7y ago
>> Any satellite can physically navigate in space, Not cubesats. You need some sort of an engine and an orientation mechanism. You can forgo the engine if you only want to play around with drag via orientation, but the average cube/nano sat moves, falls, along the same path as any other bit of metal up there.
- dylan604 7y ago
  So cubesats are designed to only be in orbit for a short time? Even at LEO, without correction burns, things eventually re-enter the atmosphere. I guess it’s a feature, not a bug?
  - TeMPOraL 7y ago
    It is a feature. It ensures they don't litter orbits forever.
  - Rebelgecko 7y ago
    Many cubesats have engines, and even those that don't can use their reaction wheels to do small maneuvers by changing their orientation which causes drag to change the orbit. There are other methods to deorbit like tethers, but due to reliability they're not used often

na85 7y ago

I think your understanding might be incomplete. To "stop" in space, relative to a viewer on the ground, means going into geostationary orbit. Or, I suppose, to a Lagrange point. To borrow an XKCD-ism, space isn't high so much as it's fast. You have to go very very fast to stay in orbit, and if you were to attempt to slow down and stop whilst orbiting, you'd essentially be executing a de-orbit burn and would find yourself re-entering the atmosphere.

diydsp 7y ago

any idea why it seems the thruster is offside? [0] Doesn't that complicate mobility/control? [0]https://en.wikipedia.org/wiki/Boeing_X-37#/media/File:X_37B_OTV-2_02.jpg https://en.wikipedia.org/wiki/Boeing_X-37#/media/File:X_37B_...

jonathankoren 7y ago
I don’t think anyone here has the knowledge to say. You’d normally want the thrust vector to pass through the center of mass. Maybe on orbit it hangs stuff off the starboard side.
m0zg 7y ago
Don't know why it's offset (probably just "form over function", it doesn't need to look pretty), but it's likely no big deal. Those thrusters are gimbaled anyway, it can point wherever you want, and is typically adjusted in realtime. https://www.youtube.com/watch?v=7Wtg_3Y4lFc https://www.youtube.com/watch?v=7Wtg_3Y4lFc
wongarsu 7y ago
Probably to fit something else there. The thruster can gimbal/pivot, and the software already has to measure the current center of mass of the vehicle because payloads etc affect it enough to make you go in circles. So accounting for an offset thruster might not even be a software change since it's a parameter the software already has to find automatically. Also note how the main engines of the space shuttles are really far offset at launch and fire at a weird angle to compensate.
baybal2 7y ago
It means that its centre of mass is significantly shifted, and that is likely mandated that it was built specifically to carry that payload.