Comments on: NASA reveals three year delay in its New Frontiers planetary mission program

By: markedup2

markedup2 — Wed, 30 Aug 2023 15:58:10 +0000

In regard to my budgetary concerns in the supernova thread: Solar System research, at least out to Jupiter if not further, seems to be something we should be funding (attempting to avoid boondoggles, of course) because it has more near-term use.

By: David Ross

David Ross — Tue, 29 Aug 2023 20:27:33 +0000

Mr Fleming, putting 75 kg on-course to Neptune isn’t a problem. Voyager 2 did it. The planets are admittedly not-as-well aligned now as they were in the 1980s but I am sure you are right that laser-pushed sails (say) can get the cargo to 30 AU without (much) recourse to internal propulsion.
My point is that Voyager 2 flew right by Neptune.
To get into ice-giant orbit, can magnets slow down a fast-moving payload?
Also I want more than 75 kg in orbit.

By: Stephen Fleming

Stephen Fleming — Tue, 29 Aug 2023 19:59:31 +0000

David Ross, I’d substitute “advanced propulsion” for “fusion.” Things like plasma magnetic sails have the potential to place a substantial (75 kg) orbiter around Neptune in a year.

By: David Ross

David Ross — Tue, 29 Aug 2023 19:42:39 +0000

Some of the New Frontiers proposals I’d read honestly didn’t look much better than the Mars Sample Return boondoggle. Let’s pick on Uranus (and on Neptune).
I don’t think we can project a worthwhile orbiter past Saturn; not without a major advances in thrust and ISP. Look what a circuitous route even Cassini took (and they used plutonium).
Princeton is doing well in creating their fusion engine, so I’m not laughing it out of the room. I *am* laughing at any proposals to get useful cargo to 20 AU and then decelerated into orbit without fusion.

I think we should concentrate on lunar and asteroidal colonies. There’s a place for Deimos in this scheme as well, but not yet.