[AR] Re: Catching Oumuamua
- From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
- To: Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Tue, 16 Mar 2021 19:45:33 -0400 (EDT)
On Wed, 17 Mar 2021, Jake Anderson wrote:
Not quite home built but this just got some attention at nasa
https://www.nasa.gov/directorates/spacetech/niac/2021_Phase_I/Extrasolar_Ob
ject_Interceptor_and_Sample_Return/
Not quite anywhere built, in fact. :-) This is a small NIAC (NASA
Innovative Advanced Concepts) Phase I grant, i.e. it's a first look at an
interesting new technology that might *eventually* make a big difference,
but isn't really expected to be flight-ready within a decade.
They're claiming an isotope power system (doesn't seem to be exactly an
RTG, but it's difficult to tell) with W/kg roughly competitive with good
modern solar arrays. That would be useful, especially for the outer solar
system, but not revolutionary. How they would get a delta-V "on the order
of 100km/s" out of that is less clear, unless the mission is intended to
last *many* years so that it could use very low thrust. (There is no
great problem building ion thrusters with very high Isp, except that with
a power supply of realistic size, their thrust is too low to be very
useful. Conventional ion thrusters basically trade off Isp for thrust.)
For a guess, it's a "betavoltaic" system -- a beta-emitting isotope plus
unorthodox semiconductor power conversion that uses the energetic beta
particles directly rather than converting the energy to heat first. At
the moment there doesn't seem to be much technical detail available on
exactly what they have in mind.
Henry
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