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Comment by amai | Hacker News Reader

The big problem with nuclear propulsion is always: What happens if a rocket with such an engine explodes at the start? What happens if it explodes in the upper atmosphere or accidentally reenters the atmosphere?

A "simple" nuclear engine might just contaminate a huge area in such a scenario. What does this new engine do, to prevent that from happening?

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> The big problem with nuclear propulsion is always: What happens if a rocket with such an engine explodes at the start?

The big problem is that most people don't realize that isn't a problem at all.

We've been launching radiation-powered devices into space for decades in the form of RPS's, Radioisotope-powered systems. In one launch, the rocket exploded and even then the radioactive parts were unharmed[0]

And 'accidentally reenters the atmosphere' isn't really a thing. Once an object is in orbit above a certain height, it takes a lot of energy to get it out of orbit. The only alternative is waiting for the very faint amount of atmosphere to drag on it and bring it down- and anything about 1000km, that would be decades of waiting.

We launch the radioactive components safely, as we have lots of experience doing. We then assemble the nuclear engine in-orbit at an orbit above 1000km. Then we go to Mars!

[0]https://rps.nasa.gov/about-rps/safety-and-reliability/

Would there be any way to do a test flight of this technology without the in-orbit infrastructure?

Maybe we should just blow up a nuclear bomb in space just to make sure there isn’t any weird interaction of physical forces we didn’t anticipate for an explosion of that magnitude in space

Its very simple. Build it in space. Use non-nuclear landing crafts.

You still need to get those materials into space somehow.

In small doses, not under 'explosion' condition?

u mine the materials in space

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