23 hours ago, dmwalker said:

Without oxygen, hydrogen isn't flammable. It needs 24% to 96% air in order to form a flammable mixture. Outside that range, it doesn't burn. The only oxygen available would be in the breathing air, which, I imagine would be well separated from the hydrogen. Conventionally powered spaceships would be more like the Hindenburg since they carry both chemicals required for combustion.

I don't think it actually ignites the Hydrogen.  It uses the fission reactor to superheat and pressurize the gas and uses that for propulsion.  This would eliminate the requirement to have *both* Hydrogen and Oxygen tanks.  I like the plasma engines better.

Yes, the conventional rockets are also Hindenburgs, and we've seen some explode spectacularly and tragically.  They are very dangerous.  My point with this new nuclear propulsion is that you're not only still carrying highly flammable Hydrogen gas, but a fission reactor as well, which has its own dangers.  For example, what if a micrometeor hits the reactor?

We need better propulsion technology.  Fusion will be the end all be all, but its several decades away despite the pretty picture that the company websites paint.

Dave

Edited December 18, 20232 yr by dave2013

Problem solved!  Warp drive invented!  No fuel to carry!

 

1 hour ago, dave2013 said:

I don't think it actually ignites the Hydrogen.  It uses the fission reactor to superheat and pressurize the gas and uses that for propulsion.  This would eliminate the requirement to have *both* Hydrogen and Oxygen tanks.  I like the plasma engines better.

Yes, the conventional rockets are also Hindenburgs, and we've seen some explode spectacularly and tragically.  They are very dangerous.  My point with this new nuclear propulsion is that you're not only still carrying highly flammable Hydrogen gas, but a fission reactor as well, which has its own dangers.  For example, what if a micrometeor hits the reactor?

 

 

You are overstating the risks, I would say. Regardless, it's happening in 2027 if all goes to plan.

Reactors are shielded, a micrometeor wouldn't be an issue. And I don't see how it's a "Hindenburg" with no oxygen present to generate an explosion. Combustion can't occur in a tank that only contains hydrogen. And space, of course, is absent of oxygen.

 

"In May 2022 DARPA issued an RFP for the next phase of their Demonstration Rocket for Agile Cislunar Operations (DRACO) nuclear thermal engine program. This follows on their selection, in 2021, of an early engine design by General Atomics and two spacecraft concepts from Blue Origin and Lockheed Martin. The next phases of the program will focus on the design, development, fabrication, and assembly of a nuclear thermal rocket engine.^[2] In July 2023, Lockheed Martin was awarded the contract to build the spacecraft and BWX Technologies (BWXT) will develop the nuclear reactor. A launch is expected in 2027.^[3]"

 

Edited December 18, 20232 yr by martin-w

2 hours ago, martin-w said:

And I don't see how it's a "Hindenburg" with no oxygen present to generate an explosion.

That's true.  As long as the hydrogen tanks are completely isolated from the parts of the ship where oxygen is present, which it likely would be.

2 hours ago, martin-w said:

A launch is expected in 2027

I'd be willing to bet you a lot of money that a prototype, experimental, small-scale engine demonstration, the success of which is not guaranteed, won't happen until 2030 or later.

I hope it does happen in 2027.

Dave

13 hours ago, dave2013 said:

I'd be willing to bet you a lot of money that a prototype, experimental, small-scale engine demonstration, the success of which is not guaranteed, won't happen until 2030 or later.

 

Impossible to say. Quite a few variables. Not something that can be predicted definitively. Given that we are in a new space race, and a certain nation could get to the Moon and Mars first, they are expediting the process. If the funding continues then there's no reason why a demonstrator can't be in orbit in 3 years time. 

Optimism scale below... You in red, me in blue. 😁

 

1   2   3   4   5   6   7   8   9   10

 

 

Edited December 19, 20232 yr by martin-w

On 12/19/2023 at 4:11 AM, martin-w said:

Optimism scale below... You in red, me in blue. 😁

 

1   2   3   4   5   6   7   8   9   10

Me on 1.

Noel

It's the colors, not the numbers... or is this another of their tricks?