A new type of SSTO

[kerbiloid]

3 minutes ago, sevenperforce said:

You also need liquid landing engines because you cannot exactly land using pusher-plate retropropulsion.

Using a pushed-plate retropropulsion lander you always land accurately

Spoiler

in the center of the crater.

 

[wumpus]

21 minutes ago, sevenperforce said:

Nuclear pusher-plate launch doesn't really pose a major health risk. As long as it's done far enough away from population centers, with "clean" mostly-fusion nukes, the global increase in cancer risk is very low.

And you can't use it all the way to the ground, after all -- you're going to have to switch to thrusters at some point because pulse propulsion does not play well with landing pads.

Sorry, they left out the actions of the magnetosphere when making those calculations.  All the residue from all the nuclear explosions within roughly geosync orbit will come back to Earth (of course that means safer isotopes than when the bomb went off, but they are still coming back and wrecking havoc on Earth).

You can mostly ignore that by polar launches (i.e. launching out of Antarctica), but launching out of the Mohave is a no-go.

And you aren't landing an Orion, unless that "bomb ignited with a laser" works a lot better than the NIF can do.  In general, the energy of nuclear weapons don't scale much with cost, so you might as well use the biggest bombs you have.  And that means a big Orion.  And that means landing is right out (nevermind that it means all residue fires straight to the Earth instead of the other way around).

[DDE]

1 hour ago, sevenperforce said:

As long as it's done far enough away from population centers, with "clean" mostly-fusion nukes, the global increase in cancer risk is very low.

Actually, per some models you'd be doing the world a favour by combatting insufficient radiation exposure.

1 hour ago, sevenperforce said:

And you can't use it all the way to the ground, after all -- you're going to have to switch to thrusters at some point because pulse propulsion does not play well with landing pads.

The greater problem is that Orion can't survive flying through a (quasi-static) nuclear fireball.

[kerbiloid]

Btw. When the Orion developers were planning Martian expeditions, at last they finished with landing one Orion (with crew of 50) by chemical rockets and leaving it there as a permanent base for 20. While other Orions of the expedition should stay in orbit.

Edited August 30, 2019 by kerbiloid

[Ultimate Steve]

On 8/28/2019 at 4:17 PM, DDE said:

Actually, per some models you'd be doing the world a favour by combatting insufficient radiation exposure.

Can you elaborate?

[DDE]

2 hours ago, Ultimate Steve said:

Can you elaborate?

A 2005 metastudy by the French Academy of sciences noted that about 40% of the low-exposure experiments indicated beneficial effects of radiation exposure. This paper, among others, is held up by a small community of believers in radiation hormesis.

[kerbiloid]

I also read this in 80s-90s, that some low level of radiation is required for proper organism functioning.
Maybe, that's so. Say, a natural stimulator of regeneration processes killing ill cells, or so. A permanent mini-disaster forcing the organism to struggle.

Edited September 1, 2019 by kerbiloid

[DDE]

7 hours ago, kerbiloid said:

I also read this in 80s-90s, that some low level of radiation is required for proper organism functioning.
Maybe, that's so. Say, a natural stimulator of regeneration processes killing ill cells, or so. A permanent mini-disaster forcing the organism to struggle.

The basic argument is that advocates of the Linear No-Threshold model underestimate both the ability of the organism to counter radiation damage and the stimulating effect it can have on the immune system. More locally, for example, until the 1950s radiation was used to very effectively treat gas gangrene by bombarding the oxygen-averse microbes with free radiation-induced oxygen radicals - whereas today the usual counter is amputation.

More mundanely, and one perhaps you but not our Anglophone friends have heard of are radon baths.

[kerbiloid]

10 minutes ago, DDE said:

More mundanely, and one perhaps you but not our Anglophone friends have heard of are radon baths.

I have some of them not far away from my place.
_{(Radon baths, I mean.)}

Edited September 1, 2019 by kerbiloid

[sevenperforce]

5 hours ago, DDE said:

More locally, for example, until the 1950s radiation was used to very effectively treat gas gangrene by bombarding the oxygen-averse microbes with free radiation-induced oxygen radicals - whereas today the usual counter is amputation.

You can also shortcut by simply putting the patient in a high-oxygenated hyperbaric chamber. No radiation needed, and the microbes can't reproduce when exposed to high levels of oxygen. Not as good a prognosis as amputation, but better than the alternative when dealing with infections in the torso.