Nuclear Conversion for Starship

That&#x27;s a useful analysis.<p>Nuclear power gives you more energy, but you&#x27;re still limited by how much reaction mass you can carry.<p>The plans that work look like early 1960s NASA plans - build infrastructure in orbit, assemble nuclear power interplanetary craft in orbit, nuclear power is from planetary orbit to planetary orbit only. That was Wernher von Braun&#x27;s &quot;Man Will Conquer Space Soon&quot; plan.[1]<p>The Apollo program, at US$20 billion, was the <i>economy</i> version. To the moon and back, no space station, no permanent infrastructure in space.<p>[1] <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Sz7njI0wEIw">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Sz7njI0wEIw</a>

Nuclear doesn&#x27;t work with Elon&#x27;s approach to development. You can&#x27;t blow up multiple nuclear rockets within the atmosphere just to learn what needs fixing for the next attempt.<p>Then again, it&#x27;s looking like the whole &#x27;fail fast&#x27; approach is over anyway, with Starship grounded by red tape.<p>A full-stack Starship failure is seemingly too big&#x2F;dramatic&#x2F;risky to get away with doing repeatedly, especially admidst the politics of Twitter&#x2F;X.

AFAIK, the only nuclear rocket that makes sense is landing a reactor on an icy comet and using it to shoot super heated steam wherever you want thrust.<p>#seveneves

The summary of this methodical and enlightening article from an excellent source for mathematically backed science fiction &#x2F; space travel is:<p>No. Nuclear is not worth it for starship, as the added engine weight limits the additional delta V and the additional challenges of handling nuclear material.

This is seriously underselling what US nuclear rocket program of the &#x27;60s [1], by calling everything that came after &quot;modern&quot;. That program was the only one that built something, everything else was speculation on paper.<p>The obstacles faced by the NERVA project were immense, and the iterations achieved spectacular improvements in record time. That project that lasted for less than one decade and was done on a shoestring budget is not quite the equal of the Manhattan project, but it&#x27;s not much below it. It achieved the highest density of power generation by maybe a factor of 100 compared to any other reactor in history.<p>All that stuff was pretty much lost. NASA is trying to revive this, but it will not have legs. We simply don&#x27;t have the same pool of talent to recruit from. In the 60&#x27;s there were lots of scientists and engineers that had first hand experience building nukes and nuclear reactors. Now this country has not built a reactor in 3 decades, with the exception of Vogtle.<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;NERVA" rel="nofollow noreferrer">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;NERVA</a>

First I am reading about nuclear engines applied to Starship. I wonder if it would be more practical to launch the reactor, fuel, and propellant into orbit using conventional rockets. Later a mission could pick up this Nuclear rocket engine and use it as a sort of booster while not inside a strong gravitational field. Ofc that doesn’t sound like Starship at all.

&gt;So will going Nuclear be worth it?<p>&gt;The short answer is no<p>&gt;If we need the full performance advantage of nuclear propulsion, we should design a spaceship that is intended for it from the get-go. It never lands, only going from orbit to orbit, so there is no need for heat shielding, flaps, high thrust engines, thick steel structure or aerodynamic shaping requirements.

I think we&#x27;ll see nuclear propulsion for Starship variants that receive fuel rods in orbit and are not designed for reentry. Interplanetary logistics between Earth&#x2F;Moon&#x2F;Mars orbits.

Since this is presumably for interplanetary, and not heavy lift, I&#x27;m not sure why you&#x27;d use this over just having thin-film solar + pulsed plasma thruster (which can do anything from 1km&#x2F;s to 3000km&#x2F;s exhaust velocity).

I only skimmed the article; but as I understood it the liquid hydrogen here is being used strictly as ejecta. It is not being combusted, the way that it is used in the space shuttle boosters.<p>If that is the case, liquid hydrogen seems like an awful substance -- hard to produce and transport, hard to store and the mass required to support keeping it is not insubstantialy, all for a mass density of ~70g&#x2F;L.<p>Why not just use water? Water is 1000g&#x2F;L and can be stored without any real effort at all. If all you&#x27;re doing is shooting it out the rear end of the rocket with as much energy as possible, it&#x27;s mysterious why you would even consider liquid H2.

A loosely related article from a few days ago about Mars Cyclers will be of interest.<p><a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=38086518">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=38086518</a> <a href="https:&#x2F;&#x2F;planetocracy.substack.com&#x2F;p&#x2F;mars-cyclers" rel="nofollow noreferrer">https:&#x2F;&#x2F;planetocracy.substack.com&#x2F;p&#x2F;mars-cyclers</a>

What are the safety ramifications? Is there not a radiation fallout from the exhaust?

Might be a stupid question: would this result in radioactivity just flying through space as we try to propel spacecraft with it?

Interesting thought experiment, not shocking at all that a craft not designed to use NTP wouldn&#x27;t work well with it.

Aren&#x27;t SpaceX launch explosions big enough already?

why aren&#x27;t they just researching the creation of dilithium crystals?

yay radioactive shit falling from space again

The design is not advanced enough, they should be thinking of<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Fission-fragment_rocket" rel="nofollow noreferrer">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Fission-fragment_rocket</a><p>So here is my science fiction theory: fusion will never be possible, but fission already is. So in the galactic civilization, rare uranium is the most valuable resource since it enables interstellar travel. Uranium is only produced in the collisions of neutron stars, so we are lucky to have any.<p>We should not squander our uranium for power generation when we can use solar for that. It&#x27;s like not using oil or gasoline for heating.. we need it for transportation.