NASA eyes nuclear propulsion


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Early steps to get back skills we had in the 1960's, but it's a start.

When they discuss specific impulse it's a form of efficiency, so more is better. Liquid fuel rockets generally run between 200 and 375, but nuclear thermal could exceed 900.

Aviation Week....

Marshall Eyes In-Space Nuclear Propulsion

Huntsville, Ala. ? NASA?s Marshall Space Flight Center here is expanding the scope of its nuclear technology work to encompass the Obama administration?s shift away from the canceled Constellation back-to-the-Moon effort toward a more open-ended technology development portfolio.

During the Constellation years, Marshall worked with the Department of Energy on nuclear-power technology that might one day power a lunar outpost. While Los Alamos and other national labs handled the radioactive material, NASA experts here used heating elements to simulate nuclear fuel and concentrated on the power systems that would generate electricity on the Moon.

That work continues, but it has expanded to encompass another technology goal under the new Obama policy: advanced in-space propulsion. In a nondescript high-bay building, the power-plant team has installed a nuclear-thermal rocket environmental simulator, which flows gaseous hydrogen over heating elements that mimic different nuclear-fuel configurations. The idea is to test the way different materials react with the hydrogen at high temperature and pressure.

?Before you move into any nuclear testing, you have a good feel for how those elements might behave,? says project engineer Dave Houts.

The setup includes a mass spectrometer and optical pyrometers that monitor temperatures and materials performance during runs. Testbed operators retreat to a control center away from the pressure chamber during tests, but only to protect their ears from the noise they generate.

Although NASA conducted nuclear-rocket tests in the 1960s, none will be run here. The prescreening of simulated nuclear elements could help humans use radioactive fuel to reach Mars and other distant destinations faster, reducing the time they spend in the dangerous space-radiation environment.

?Because you can use hydrogen as a propellant, which has a very low molecular weight, a nuclear thermal rocket allows you to get a very high specific impulse even at reasonable material temperatures,? Houts says. ?So for what we consider early systems, a first-generation system, we should be able to achieve a 900-sec. specific impulse or better, so you?re roughly twice that of a chemical engine. We think we can go up from there using some of the advanced materials, advanced cycles and advanced geometries in the actual system.?

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I have no idea why Obama canceled Constellation. I remember being excited when I heard we were going back to the moon and was ****ed to hear it was canceled. Obama's plan is to get to Mars by the mid-2030s. I don't really understand why going back to the moon is considered such a project. We've already done it. We just need to build modernized shuttle and re-entry craft. The US Space program is a joke right now. We're relying on Russia to get into space. To me, the space program is one of our biggest points of pride but it's really not doing good right now.

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Obama has NO plan to go to Mars. There is no mission plan nor is there even a proposed future budget. His most ambitious goal is an asteroid mission. Most everything else is basic research and PowerPoint.

As for Constellation; that was a correct decision and not just Obama's - the Augustine commission, made up of lead astronauts, engineers and other such types determined its rockets, Ares I and Ares V, were flawed from the get-go and the whole program was hopelessly over-budget. Ares I also had serious vibration issues due to thrust oscillation in its solid 1st stage that forced it to gain several tens of tons of mass to mitigate. This would have resulted in Ares I having difficulty lofting the heavy Orion spacecraft to orbit.

They hang on by threads as the commercial Liberty launcher (with major mods - a European Ariane upper stage for one) and the Space Launch System (SLS), but blown budgets are still a huge problem. The problem is so bad regular flights of SLS wouldn't happen until 2018-2022 at best, and then at a rate of only 1 flight a year.

Reason? Cost, at >$1 billion a launch - not counting the payload. 2 Falcon Heavy launches with a split payload would only run about $250 million.

Also a problem is the growing realization that smaller, current and near-future launchers (Atlas V, Delta IV, Falcon 9 Block 2, Falcon Heavy, Atlas V Heavy etc.) combined with fuel depots would be faster, cheaper and support much higher launch rates than the SLS.

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you're starting to sound like Zubrin, Doc...Obama went on record to say he expects to be around for a Mars mission in the 2030's, and Congress has approved funding for it. why is the sudden change in mood?

of course i agree with pip, we're not doing what we should be doing in space, i.e our future. and by we i mean the human species, not just the US. and NASA reconsidering nuclear propulsion is a given, the NERVA reference design ships could have gotten to Mars in like ten days, no? we really are reaching for past glories, but it's never too late to do the right thing. i'm getting a lot of mixed signals regarding space lately, one minute it's all doom and gloom, and the next it's we're bringing back nuclear rockets, which one is it?

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Embrace the Atom!

1958_ford_nucleon.jpg

I thought someone else was working on nuclear engines as well, a private firm. They started a few years ago.

Be interesting, I expect they would not use these in atmosphere just in case, so maybe a high orbit spacedock like star trek?

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NASA roadmap link....

On page 10 is the schedule showing nothing more than missions to a near Earth asteroid or deep space habitat (DSH) out to 2033, and Mars at an undetermined date after that. Fact is, the SLS budget only runs to 2030 with few crewed missions and no funding for the DSH mission.

You just can't pull a Lagrange point DSH or Mars mission out of your butt at the last minute. It takes NASA at least 10 years of planning just for something like DSH. Just look at how long JWST has taken to get to a Lagrange point.

The plan chosen is asteroid first, which could be done with just 2 docked Orion's - one for consumables and as a backip return vehicle - but going to the moon or Mars needs an infrastructure whose components aren't likely to be seen until 2040-2050 unless sonething changes drastically.

Could commervial speed this up? Absolutely! But that isn't in the cards, yet.

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Doc - what caused this change in direction? one minute we're talking Mars by 2020 and Obama says he's going to be around to watch the landing, now we're talking 2030's or later? i thought Congress already approved the funding with the 2010 NASA Authorization Act. thanks for posting that PDF, i will read through it, it looks very interesting, but depressing ultimately cause it means very few of us talking here will be alive to see humans working and living on other worlds in a viable manner. HOWEVER, we need to be realistic and honest about these things. we started flying in our own atmosphere just over a century ago, with the majority of human population only coming within sight of a plane in the last 20-30 years. air travel still isn't trivial for most people, and to be honest the Apollo missions were in retrospect premature because no one had any intention of following up on them. without that follow up, they became like the first voyages of Europeans to the Americas, or the travels of Zheng He...a cool exception, but still an exception.

realistically, as much as it breaks my heart to acknowledge this on a personal/selfish level, a timeline of viable Moon/Mars settlement by the 2070's and viable interstellar travel by the 2150's is what we can 100% count on. our children will spread through the galaxy, but it will take time. a lot of time. it is space we're talking about after all, not 2000 miles of Earth-bound ocean.

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The problems come down to a lack of money due to the world downturn and a lack of vision and will on the part of our leadership. That simple. The technological issues are daunting, but solvable by using fuel depots, electromagnetic shielding, plasma propulsion, etc.

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there are no technological issues. we've had the tech to build Orion ships and Dyson spheres since the 1950's. we don't have the will. and economic downturn? maybe it's because our single-world design is quickly running out of growth industries. let's try to think together with our brilliant politicians which avenues could possibly lead us to new growth industries...oh maybe expanding IN SPACE?

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