Project Bifrost: (Fission) Rockets of the Future?

astroengine writes "Researchers from Icarus Interstellar Inc. and General Propulsion Science have announced their intention to pursue the development of Nuclear Thermal Rockets and other fission-based space technologies. The aim? To revolutionize space travel, ultimately paving the way to the goal of sending a probe to another star."

legal?

[kaspar_silas]

Sounds exactly like 1955s project Orion. And similarily to it I don't think they can actually legally work on this idea due to international nuclear regulation. In particular the comprehensive test ban treaty. Because after all what you are designing is something very like an icbm with a "dirty" warhead. I god damn guarantee if Iran openly worked on this the US would bust itself to attack ASAP.

Nothing new

[tsotha]

There's nothing new here. It's another "study" rehashing technology that's been rehashed over and over for at least sixty years. And anyway nuclear thermal rockets don't address the biggest problem we have with space exploration, which is getting to orbit in the first place. Heinlein famously observed "Get to low-Earth orbit and you're halfway to anywhere in the solar system." But the converse is also true - no matter how good your deep space rocket is you're only half way to where you want to be.

Nuclear thermal rockets have a wonderful ISP, but they don't have as much thrust as chemical rockets, and they're heavy. Even assuming you wanted to use one for the first stage it probably wouldn't have enough thrust to do the job. And you wouldn't want to start one up on earth, either. They never did figure out how to keep bits of the radioactive core from breaking off and entering the exhaust stream,

Re:Good luck

[Bill Currie]

Yes, the escape velocity is 42.1km/s. But anything in Earth's orbit already has a velocity of 29.78km/s (+/- a bit if in orbit around the Earth). This means that the delta-V required to escape the solar system from Earth's orbit is 12.32km/s. Less than half that required to de-orbit and fall into the sun.

This is actually a mistake that I make quite often (forgetting to factor in the current orbital velocity).

Re:Good luck

[donscarletti]

So, I mention de-orbiting (WRT the Sun) something already IN earth orbit, then you add in the delta V to get into LEO _again_, clearly distorting the number to prove your point. Also, you suggest needing to go to zero, which is untrue, if something enters the corona it will be decelerated, the corona takes about 2 degrees of arc in the sky meaning an elliptical orbit will be just as good, which does not require zero orbital velocity.

Re:Good luck

[BlueStrat]

You mean like the Challenger and Columbia? Except with nuclear fallout.

What, are you a Flash Gordon fan!?

Nobody designs even a chemical-powered interplanetary spaceship to land it's main mass (including it's main propulsion system) on a planet surface. That's what landers are for. Even Apollo used a Lunar Module to land on the moon and a small Command Module for Earth re-entry.

This thing would be assembled in orbit and would never land on a planet. For something like a nuclear-powered interstellar spaceship, I imagine most of the construction would be done in low Earth orbit and then moved to a parking orbit at a La Grange point for final departure preparations, including loading the nuclear fuel.

I think you understand this, but are allowing your nuclear fears to cause you to post ridiculous and unrealistic scenarios in an effort to fight the idea of nuclear-powered space propulsion systems.

Strat