Very sorry to hear about your mother, Bill. If you know Mike, I'd ask
him. If not, I can.
On 2/26/21 3:19 PM, William Claybaugh wrote:
Rand:
I remain interested in confirming that 60 km / sec will catch up and that a plane change at Jupiter followed by a solar gravity assist and some catch-up using an efficient RTG and a commercial electric thruster could do the job.
My mother—who died of COVID a few weeks ago—lived her entire very long life with both feet firmly planted on cloud nine.
My living is focused in what we might actually accomplish in the next few years.
Bill
On Fri, Feb 26, 2021 at 4:06 PM Rand Simberg <simberg@xxxxxxxxxxxxxxx <mailto:simberg@xxxxxxxxxxxxxxx>> wrote:
Doesn't need to be a city burner to be good propulsion. In fact,
that would be counterproductive if it burned up the sail, which it
would. You want enough power density to get good thrust without
heating it beyond its heat-rejection capability.
On 2/26/21 3:04 PM, William Claybaugh wrote:
Rand:
So far, there ain’t no city burning lasers in orbit.
I’m interested in what might be accomplished today, or in the
next few years.
Bill
On Fri, Feb 26, 2021 at 4:01 PM Rand Simberg
<simberg@xxxxxxxxxxxxxxx <mailto:simberg@xxxxxxxxxxxxxxx>> wrote:
Not sure I have the bandwidth to do that, but I'd ask John
Carrico, if you know him. He does that sort of thing for
recreation. It certainly doesn't seem implausible to me.
That's the sort of thing that it would be nice to have a
laser in orbit or on the moon that could push a sail. That
would get it there a lot sooner.
On 2/26/21 2:52 PM, William Claybaugh wrote:
Rand:
I’d be real interested as to whether your independent
astrodynamic analysis—at the spreadsheet level—could confirm
that 60 klicks per second will catch it in about 20 years
and that a plane change at Jupiter followed by a solar
gravity assist and some makeup electric propulsion would
allow a flyby.
Bill
On Fri, Feb 26, 2021 at 3:35 PM Rand Simberg
<simberg@xxxxxxxxxxxxxxx <mailto:simberg@xxxxxxxxxxxxxxx>>
wrote:
I think there is scope for a lot of private missions in
the solar
system. Is Milner still planning an Enceladus mission?
On 2/26/21 2:29 PM, William Claybaugh wrote:
> Since we are not talking about homebuilt rockets, I
was wondering if
> we might talk about homebuilt space missions:
>
> A top level analysis suggests it would take about 60
Km / sec to catch
> Oumuamua in about 20 years.
>
> Another very top level analysis suggests that a
gravity assist at
> Jupiter (solely to turn the plane from near ecliptic
to near that of
> Oumuamua; near to but less than 90 degrees) followed
by a 50 solar
> radii assist at the Sun (Parker is doing 10 radii as I
recall but it
> carries way too much heat shield for this mission) can
pretty
> certainly get to 50 km / sec.
>
> One of NASA Glenn’s Stirling cycle RTG’s tied to an
existing
> commercial electric thruster appears capable of making
up the
> difference with a big fuel tank.
>
> Assuming a New Horizons-like spacecraft, but much
smaller, a flyby
> seems possible based on this very top level analysis.
>
> I’d be real interested in helpful comments.
>
> Bill