3 ms·

Is it possible the impact will affect trajectory of the comet?

okket 10y ago
From the FAQ: How fast will Rosetta impact the surface? One of the key features of the trajectory design is to minimise the spacecraft's relative velocity at impact. The current scenario predicts that the impact velocity will be around 90 cm/s, around walking pace. It is worth keeping in mind that Rosetta was not designed as a lander, and some of its appendages including the 32m-wide solar panels will be damaged by the impact. This energy dissipation will very likely ensure that the escape velocity will not be exceeded during any bounce, thus preventing Rosetta from returning to orbit after impact with Comet 67P/C-G. http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_grand_finale_frequently_asked_questions http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rose... (I read from this that it is highly unlikely that the comet trajectory is affected in a noticeable way by the impact. See also the answer from symmetricsaurus above. This would qualify as a good FAQ, IMHO.)
- lucidstack 10y ago
  It's fascinating how brilliant this solution is. Let it slowly bounce on the comet, so that the rebounce velocity is very low, it doesn't affect the comet trajectory in any way, and they're collecting data during the slow descent. Nice.
  - dandelany 10y ago
    Rosetta couldn't really affect the comet trajectory in a meaningful way, even if we wanted to. The comet has a mass of nearly 10 trillion kg, the orbiter is <3000 kg, and P = MV. It would need to have insane velocity to impart any meaningful momentum.
gr3yh47 10y ago
probably the same way a flea getting hit by a fastball affects the trajectory of the pitch
nkrisc 10y ago
It will. The question is if it will at all be noticeable. Given the low mass and velocity of Rosetta, I'd say not by much.
symmetricsaurus 10y ago
No, Rosetta is already in orbit around the comet. By the principle of conservation of momentum the impact will not change the total momentum of the system (comet plus spacecraft). The changes in trajectory happens when the engines are used on the spacecraft.
- AnimalMuppet 10y ago
  Which means that Rosetta already affected the trajectory of the comet - when it entered orbit.
- dandelany 10y ago
  Would this still hold true if Rosetta were commanded to slam into the comet hard enough for some of the impact debris to reach escape velocity? (Not trying to nitpick your argument, it certainly holds true for the soft landing case, but I'm curious how strong this axiom is)

okket 10y ago

From the FAQ: How fast will Rosetta impact the surface? One of the key features of the trajectory design is to minimise the spacecraft's relative velocity at impact. The current scenario predicts that the impact velocity will be around 90 cm/s, around walking pace. It is worth keeping in mind that Rosetta was not designed as a lander, and some of its appendages including the 32m-wide solar panels will be damaged by the impact. This energy dissipation will very likely ensure that the escape velocity will not be exceeded during any bounce, thus preventing Rosetta from returning to orbit after impact with Comet 67P/C-G. http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_grand_finale_frequently_asked_questions http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rose... (I read from this that it is highly unlikely that the comet trajectory is affected in a noticeable way by the impact. See also the answer from symmetricsaurus above. This would qualify as a good FAQ, IMHO.)

lucidstack 10y ago
It's fascinating how brilliant this solution is. Let it slowly bounce on the comet, so that the rebounce velocity is very low, it doesn't affect the comet trajectory in any way, and they're collecting data during the slow descent. Nice.
- dandelany 10y ago
  Rosetta couldn't really affect the comet trajectory in a meaningful way, even if we wanted to. The comet has a mass of nearly 10 trillion kg, the orbiter is <3000 kg, and P = MV. It would need to have insane velocity to impart any meaningful momentum.

gr3yh47 10y ago

probably the same way a flea getting hit by a fastball affects the trajectory of the pitch

nkrisc 10y ago

It will. The question is if it will at all be noticeable. Given the low mass and velocity of Rosetta, I'd say not by much.

symmetricsaurus 10y ago

No, Rosetta is already in orbit around the comet. By the principle of conservation of momentum the impact will not change the total momentum of the system (comet plus spacecraft). The changes in trajectory happens when the engines are used on the spacecraft.

AnimalMuppet 10y ago
Which means that Rosetta already affected the trajectory of the comet - when it entered orbit.
dandelany 10y ago
Would this still hold true if Rosetta were commanded to slam into the comet hard enough for some of the impact debris to reach escape velocity? (Not trying to nitpick your argument, it certainly holds true for the soft landing case, but I'm curious how strong this axiom is)