7 ms·

Isn't most of the debris moving in the same direction? I'm imagining that being in orbit is like being on the freeway, where the traffic is all running the same

Isn't most of the debris moving in the same direction? I'm imagining that being in orbit is like being on the freeway, where the traffic is all running the same direction. Yes, getting hit by a car going 70 MPH would normally be catastrophic, but two cars bumping into each other around 70 MPH is not always a big deal.

mark-r 11y ago
I believe that would be true of geosynchronous satellites, otherwise there would be no benefit to being geosynchronous. Any pieces that break off should alter their orbit enough to be out of the way. Edit: I just got dinged for this comment, if there's a flaw in my reasoning or a study that refutes it please let me know.
ceejayoz 11y ago
Enough satellites are in polar/retrograde orbits to be an issue. Explosions from Chinese/US anti-satellite tests and accidental collisions go every which way, as well.
- Symmetry 11y ago
  The satellite that the US shot down was in a swiftly decaying orbit. That means that the periphrasis for all the debris was at least that far down and with the smaller ballistic coefficient of the debris it's all gone now.
baq 11y ago
one degree of inclination difference with otherwise similar orbital elements upon impact translates to about .5%-1% of energy of a head-on/t-bone impact. at orbital velocities this is still mindblowingly devastating. you've basically reduced a 8km/s impact into a 40-80m/s which is in 90-180mph range. result is lots of debris created in both orbital planes as both sats (you're comparing cars, so i assume you want sat-sat impact) are totalled, solar panels shattered, etc. and that's basically the smallest accidental collision in space you can imagine (not counting failed berthings/dockings and the like).
DonHopkins 11y ago
It's all moving in the same direction except for the British satellites, and satellites launched by some countries that used to be British colonies.
Arnavion 11y ago
Orbital speeds are fast. LEO orbital speed is about 8km/s (about 18,000 mph). So the collision is not between two cars going at 70+-5 mph but 18,000+-1000 mph (say). As the other comments mention, satellites also have different inclinations. Even a tiny difference of inclination projects a large speed on the axis along the two satellites, again due to the large speeds involved.

mark-r 11y ago

I believe that would be true of geosynchronous satellites, otherwise there would be no benefit to being geosynchronous. Any pieces that break off should alter their orbit enough to be out of the way. Edit: I just got dinged for this comment, if there's a flaw in my reasoning or a study that refutes it please let me know.

ceejayoz 11y ago

Enough satellites are in polar/retrograde orbits to be an issue. Explosions from Chinese/US anti-satellite tests and accidental collisions go every which way, as well.

Symmetry 11y ago
The satellite that the US shot down was in a swiftly decaying orbit. That means that the periphrasis for all the debris was at least that far down and with the smaller ballistic coefficient of the debris it's all gone now.

baq 11y ago

one degree of inclination difference with otherwise similar orbital elements upon impact translates to about .5%-1% of energy of a head-on/t-bone impact. at orbital velocities this is still mindblowingly devastating. you've basically reduced a 8km/s impact into a 40-80m/s which is in 90-180mph range. result is lots of debris created in both orbital planes as both sats (you're comparing cars, so i assume you want sat-sat impact) are totalled, solar panels shattered, etc. and that's basically the smallest accidental collision in space you can imagine (not counting failed berthings/dockings and the like).

DonHopkins 11y ago

It's all moving in the same direction except for the British satellites, and satellites launched by some countries that used to be British colonies.

Arnavion 11y ago

Orbital speeds are fast. LEO orbital speed is about 8km/s (about 18,000 mph). So the collision is not between two cars going at 70+-5 mph but 18,000+-1000 mph (say). As the other comments mention, satellites also have different inclinations. Even a tiny difference of inclination projects a large speed on the axis along the two satellites, again due to the large speeds involved.