updated Bimodal NTR Mars mission NASA GLENN-FJ&A visualizations

NUKE ROCKY44 · Senior Member

updated Bimodal NTR Mars mission NASA GLENN-FJ&A visualizations

John · Senior Member

For all other criticism of Constellation as just being a "Moon" project is was also the basis of a Mars project as well. The Mars mission in addition to the Ares V HLVs (7 units) it also used 3 Orions. One of which was modified as a Mars assent vehicle. The plan clearly needs a nuclear rocket engine as well.

I assume that on the return to Earth we make sure that the nuclear units are in a orbit (around the Sun) that won't crash into Earth? The return Orion will use its delta V to chance course so as to move to a course that will intersect with Earth.

Thanks for posting that.

GoogleNaut · Guru

First I would just like to say FJ&A Strategic Visualizations does some very fine work--I wish I could afford to hire them. They are that good!

As far as NTR's go, it is generally considered 'good' practice to utilize reserve propellants in a last, high energy nuclear burn to place the spent stage on a disposal trajectory which has a vanishingly small probability of returning (or impacting Earth) within a thousand years or more. Generally this disposal orbit will be well within the Earth orbit, or well outside it. Some disposal trajectories talk about using Venus for a gravity slingshot to Jupiter, then a slingshot over one or the other of Jupiter's poles to place the spent nuclear stage out of the ecliptic. I haven't done any delta-V calculations on this, so I don't know how much reserve propellant we're talking about. It also depends upon various parameters, like how fast the stage swings by the Earth and at what altitude. If we wanted to, we could slam them directly into the Moon and never have to worry about them returning to the Earth. That would probably be the safest, easiest way to do it. Or shoot them out to the asteroid belt. Or park them in Earth-Sun L-4 or L-5 points.

NUKE ROCKY44 · Senior Member

Agreed...

FJ&A Visualizations is like a Pixar/Disney for technical space-fantastic work.

I could ask or search for the Bimodal NTR Mars NASA Glenn team description to place some context for the FJ&A visuals. Maybe they have a blog set up to discuss (price tags & logistics) the Mars mission visuals.

Maybe park spent equipment at L1, L2 or maybe L3 these are highly stable geostatic like but how these fits in a fight dynamics regime for Mars mission is open to technical logistics with an experienced FIDO.

John · Senior Member

I thought the automatic docking systems in the Mars mission are interesting. I know that the Russians have long used an automatic docking system with their Progress vehicles.

GoogleNaut · Guru

The problems with parking a spent nuclear stage into an Earth-Moon L4 or L5 position are several: You have to decelerate it into a capture orbit about Earth (even at lunar height) which violates the tenants of 'disposal,' (don't return it to Earth's vicinity in X-amount of time.) Also to capture the stage requires a very significant delta-V to bleed of interplanetary transfer velocity, probably in the neighborhood of 6 km/s or so.

Reentering Apollo capsules plunged into the Earth's atmosphere at just over 7 mi/s (11 km/s) (37,000 ft/s.) A returning Mars Command Module would enter at a similar speed, but probably not much more than 7.5 mi/s (about 12 km/s,) because of the heavy g-loads placed on the astronauts (close to 10 g's!) To place a spent NTR into a disposal orbit requires a relatively modest burn to put it into a long range solar orbit that takes very, very far from earth.

repsky912 · Newbie

Howdy, this has been an excellent informative article! I definitely appreciate

all of your wisdom. Thanks alot .