On: Impulse Space is betting on a future where launch ...

[rbanffy]

> fairly quickly.

The delta-v maps show the minimum needed to get from one place to the other. In order to get from one place to another more quickly, you’ll need larger delta-v’s at the ends of the trip.

Even though the rest of the solar system is within reach, we don’t want to send humans to Pluto and back on 20-year missions.

[Invictus0 → rbanffy]

you mustn't be afraid to dream a little bigger darling. I can definitely imagine a mission to pluto and back.

[Loughla → Invictus0]

A 20 year mission to Pluto would be unsuccessful without cryogenic or otherwise science-magical-sleep system. I cannot imagine a single set of humans who could spend 20 years together, without any way to leave the small space of a ship, and not absolutely lose their minds.

That long of a trip means we just end up sending absolute lunatics and/or small pieces of chopped up lunatics after the inevitable murders.

[tsimionescu → Loughla]

Not to mention, it's extremely doubtful that a human body could survive anywhere close to 20 years in space.

[rbanffy → tsimionescu]

The ship would need to be very large - artificial gravity and adequate shielding for radiation and impacts would need to be provided, as well as an insane amount of redundancy and survivable abort routes. Attempting to do it with technologies we have, even with infinite funding, would be next to impossible without incurring in unacceptable risks.

[rbanffy → Invictus0]

I can too, but we’ll need much better engines than what we have now to get there and back in an amount of time a crew can function.

Sending 20 years worth of consumables and spares is complicated, as well as the moral questions about sending people on 20 year missions.

[avmich → rbanffy]

For some time an assumption - a rule of thumb of a sort - was that chemical rockets can get people comfortably around within Mars orbit, and to get further away we need something better. That "something" is likely not solid-phase nuclear engines, with Isp about twice as good as LOX/LH2, and probably not gas phase nuclear engines... but thermonuclear engines, which get closer to feasibility with advances in thermonuclear energy field. A thermonuclear engine could be more attainable than a thermonuclear electrical plant, and cheaper LEO access could be a big part of enabling technology.

Having engines like that we may talk about much faster trips to Pluto and back.

[rbanffy → avmich]

> A thermonuclear engine could be more attainable than a thermonuclear electrical plant

Very true. Nobody cares about breakeven for that use case.