3 ms·

We'll see ... personally I think the proof is in the pudding that despite having had these designs on the drawing board for 60+ years, there hasn't even been a

We'll see ... personally I think the proof is in the pudding that despite having had these designs on the drawing board for 60+ years, there hasn't even been a single complete rocket that's ever materialized for any of them, let alone a successful mission. Contrast that with the thousands of successful missions using chemical rockets over that time period. So it's not overstating it to say that there are some problems with nuclear thermal rockets, otherwise they would be commonplace by now.

nine_k 6y ago
Few people ever need long-range, heavyweight translunar space travel. Something like a Voyager does not require it. But heavy lifting to LEO and GEO us a well-paying market, drawing most of the investment. It excludes nuclear propulsion, though.
ganzuul 6y ago
Humanoid robots have been on the drawing board for thousands of years.
philwelch 6y ago
We haven’t landed anyone on Mars either, and those facts are related. The stagnation in space travel after Apollo was a conscious decision.
- CydeWeys 6y ago
  It doesn't take an NTR to land on Mars. If you're going to pin all your hopes on NTRs I think it's still going to take decades. No one is even seriously working on them. I'd much rather pin my hopes on chemical rockets in the form of SpaceX's Starship.
  - philwelch 6y ago
    > It doesn't take an NTR to land on Mars. I didn't say it did. But it's one of the two most feasible options, the second involving lunar ISRU and orbital propellant depots. NASA's Mars Design Reference Mission has consistently included NTR studies. Going past Mars and into the Belt, an NTR is practically essential. > If you're going to pin all your hopes on NTRs I think it's still going to take decades. Anything we try is going to take decades if you're talking about real time and not Elon time. But that's beside the point. The point I was trying to make is that there has been approximately zero serious investment in human spaceflight beyond LEO once Apollo wrapped up. The Soviets decided they didn't want to land on the Moon after all, the US decided they would rather build a flying space truck that goes to LEO than build on Apollo, and everyone else spent decades just catching up. Since an NTR is only useful for interplanetary flight, no interplanetary flight means no need to develop NTR.

nine_k 6y ago

Few people ever need long-range, heavyweight translunar space travel. Something like a Voyager does not require it. But heavy lifting to LEO and GEO us a well-paying market, drawing most of the investment. It excludes nuclear propulsion, though.

ganzuul 6y ago

Humanoid robots have been on the drawing board for thousands of years.

philwelch 6y ago

We haven’t landed anyone on Mars either, and those facts are related. The stagnation in space travel after Apollo was a conscious decision.

CydeWeys 6y ago
It doesn't take an NTR to land on Mars. If you're going to pin all your hopes on NTRs I think it's still going to take decades. No one is even seriously working on them. I'd much rather pin my hopes on chemical rockets in the form of SpaceX's Starship.
- philwelch 6y ago
  > It doesn't take an NTR to land on Mars. I didn't say it did. But it's one of the two most feasible options, the second involving lunar ISRU and orbital propellant depots. NASA's Mars Design Reference Mission has consistently included NTR studies. Going past Mars and into the Belt, an NTR is practically essential. > If you're going to pin all your hopes on NTRs I think it's still going to take decades. Anything we try is going to take decades if you're talking about real time and not Elon time. But that's beside the point. The point I was trying to make is that there has been approximately zero serious investment in human spaceflight beyond LEO once Apollo wrapped up. The Soviets decided they didn't want to land on the Moon after all, the US decided they would rather build a flying space truck that goes to LEO than build on Apollo, and everyone else spent decades just catching up. Since an NTR is only useful for interplanetary flight, no interplanetary flight means no need to develop NTR.