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>
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>
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>
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