Old Nerva video by NASA

[Spaceception]

This is pretty interesting

 

[DDE]

It looks like the S-N stage. It doesn't seem to have been given any serious thought, though. An interesting Apollo-esque interplanetary vessel, however. And I love the pre-Mariner canali-adorned Mars.

But I also think I'm beginning to understand the I_sp measurement unit. Finally.

 

Edited June 16, 2016 by DDE

[cubinator]

Man, those remotely controlled robotic arms looked awesome! Also, I half expected to hear "The Dune Sea" when they showed the Mars landscape, especially since that rover looked a bit like a small version of a sandcrawler. Then I realized this film is almost a decade older than Star Wars.

It's too bad NASA didn't get to do all that awesome stuff they wanted to do after the Apollo program. We would've had a base on Mars by now!

Edited June 17, 2016 by cubinator

[Spaceception]

10 hours ago, cubinator said:

Man, those remotely controlled robotic arms looked awesome! Also, I half expected to hear "The Dune Sea" when they showed the Mars landscape, especially since that rover looked a bit like a small version of a sandcrawler. Then I realized this film is almost a decade older than Star Wars.

It's too bad NASA didn't get to do all that awesome stuff they wanted to do after the Apollo program. We would've had a base on Mars by now!

Forget Mars base, we would've been around freaking Jupiter by now!

And on our way to Alpha Centauri if we didn't cancel Orion, but lets not get into that.

[Gkirmathal]

Very interesting to watch, thanks for sharing! Never seen this one

Though I find the throwing away of the nuclear stages a bit concerting. But maybe it was just the zeitgeist from the 60's till recently.

Still think B-NTR tech could work if governments and a large part of humanity can overcome their fear of having such systems launched and in operation. But we would first have to get to the stage where we have orbital 'tugs' systems, which only need to be refueled in orbit. So we don't throw away spend stages as useless scrap like we still do nowadays for the most part.

[DDE]

14 minutes ago, Gkirmathal said:

Still think B-NTR tech could work if governments and a large part of humanity can overcome their fear of having such systems launched and in operation. But we would first have to get to the stage where we have orbital 'tugs' systems, which only need to be refueled in orbit. So we don't throw away spend stages as useless scrap like we still do nowadays for the most part.

Sadly, from what I heard, the NERVA would quickly burn through its fuel rods. Almost as quickly as one long burn.

[Gkirmathal]

1 minute ago, DDE said:

Sadly, from what I heard, the NERVA would quickly burn through its fuel rods. Almost as quickly as one long burn.

In the other thread I proposed a system where the heat from fission would be replaced by induction heating. Would still need a sizeable nuclear reactor to power it though and the question is still out (in that thread) whether such system would be as efficient (thrust/isp/power req) to have real world application.

[Kerbart]

19 hours ago, DDE said:

It looks like the S-N stage. It doesn't seem to have been given any serious thought, though

 

That's because the S-N design is based on Nasa's design of the NERVA. It's not that it hasn't been given any serious thought; plenty of thought went into it.

It's that the public opinion of how terrific of an idea it was to launch a full blown nuclear reactor into orbit didn't really encourage taxpayer-sponsored funding of such a project.

Edited June 17, 2016 by Kerbart

[Nibb31]

The main reason S-N didn't get off the ground, beyond nuclear scare, was that it wasn't needed and the huge infrastructure cost. Imaging reconfiguring the Cape for a nuclear workflow, including outfitting the VAB, reworking handling and safety procedures, training personnel, building storage facilities, etc... The cost/benefit ratio was not in the favor of S-N, especially as at the same time, the Apollo Applications Program was being gutted and everybody knew that the days of the Saturn V infrastructure were reaching an end.

Edited June 17, 2016 by Nibb31

[wumpus]

1 hour ago, DDE said:

Sadly, from what I heard, the NERVA would quickly burn through its fuel rods. Almost as quickly as one long burn.

Another big issue for 1968 NERVA was fuel.  NERVA pretty much means hydrogen (others insist on other fuels without mentioning exhaust velocities or the temperatures expected for them, but mainly hydrogen).  By 1968 hydrogen was fine for a couple orbits and then a burn to Moon insertion, but NASA used Aerozine 50 to get back.  Storing hydrogen for multiple months may be possible now (or not), but it was certainly a bigger issue decades ago.

Getting back from Mars, Jupiter, etc. would be a problem, not to mention things like capture burns.  Still, any improvement in Isp for the big burns would help (unfortunately I don't think *anybody* came up with a NERVA that would work for the surface->LEO big delta-v requirement).

[DDE]

32 minutes ago, wumpus said:

Another big issue for 1968 NERVA was fuel.  NERVA pretty much means hydrogen (others insist on other fuels without mentioning exhaust velocities or the temperatures expected for them, but mainly hydrogen).  By 1968 hydrogen was fine for a couple orbits and then a burn to Moon insertion, but NASA used Aerozine 50 to get back.  Storing hydrogen for multiple months may be possible now (or not), but it was certainly a bigger issue decades ago.

Getting back from Mars, Jupiter, etc. would be a problem, not to mention things like capture burns.  Still, any improvement in Isp for the big burns would help (unfortunately I don't think *anybody* came up with a NERVA that would work for the surface->LEO big delta-v requirement).

They say the basic NERVA had an unusable TWR from the start; they need more liberty on the core design to be able to push it into surface launch class.

Generally the preferred reaction mass was ammonia. Not as difficult to store, and dissociates from the heat. ISRU water could be a low-efficiency alternative.