Adam Hibberd
Could we have done a sample return to ‘Oumuamua?
What’s that?
A sample return would go to ‘Oumuamua, dispatch an impactor, pick up the dust from the resulting impact plume using aerogel, and finally return to Earth for atmospheric re-entry with the sample on-board to be analysed by scientists on Earth.
Well this trajectory gives an answer. We could have done so if:
(1) we had detected ‘Oumuamua early enough
(2) we had a s/c lying in wait at the Sun/Earth Lagrange 2 Point (L2)
Now it’s too late for either (1) or (2) but maybe for some future ISO (another Interstellar Object like ‘Oumuamua), we could try this out? The Comet-Interceptor mission to be launched in 2029 will do a comet flyby or possibly an ISO flyby but not a sample return.
The main issue with a sample return is the huge relative velocity that the spacecraft would have with respect to the target ‘Oumuamua, probably way in excess of 60 km/s. Thus the spacecraft could well be taken out by debris ejected from the plume. Note aerogel works best for relative velocities of < 6 km/s, in other words a full order of magnitude lower than the spacecraft’s encounter with ‘Oumuamua.
So this is a big problem, not just for ‘Oumuamua specifically, but for ISOs in general.
