NASA looking at Nuclear Thermal Rockets for Mars missions

Are your bodies ready?

>The energy liberated by burning chemical fuel brought astronauts to the moon, but that rocket science makes for a long trip to Mars. And although search for a fission-based shortcut dates back to the 1950s, such engines have never flown. In August, NASA boosted those efforts when the agency announced an $18.8-million-dollar contract with nuclear company BWXT to design fuel and a reactor suitable for nuclear thermal propulsion (NTP), a rocket technology that could jumpstart a new era of space exploration.

> NTP rockets would pull all that off by offering about twice the bang for the buck that chemical rockets do. Rather than burning fuel with oxygen, a nuclear fission reactor would serve as a powerful furnace, heating liquid hydrogen and expelling the resulting gas for thrust. How much oomph a rocket gets from its fuel depends largely on how fast it can hurl particles out the back, which in turn hinges on their mass. And NTP's single or double hydrogen atoms would be up to a dozen times lighter than chemical rocket outputs.

>That atomic bean counting could add up to significant time savings. "Nuclear thermal propulsion can enable you to get to Mars faster, on the order of twice as fast," said Vishal Patel, a researcher involved in subcontract work for BWXT at the Ultra Safe Nuclear Corp. in Los Alamos, New Mexico. "We're looking at nice 3- to 4-month transit times."

space.com/38696-vintage-nuclear-rocket-could-reach-mars.html

Other urls found in this thread:

en.wikipedia.org/wiki/Nuclear_thermal_rocket
selenianboondocks.com/2010/02/payload-fraction-example-proof/
selenianboondocks.com/author/kfsorensen/
twitter.com/SFWRedditGifs

>3-4 month transit time
Or a few days to a week to Venus. Mars is cold and shit and going there is just going to be a stupid flag planting exercise.

...

This again? Are they going to be able to get around that pesky space treaty this time?

Are you referring to that treaty against using nuclear weapons in space?

Im a bit worried about having nuclear rocket propulsion being used within our atmosphere.

Should consider launching ftom the oort cloud or a bit further beuond the ISS.
Nuclear fallout is scary for me, esp if there's a disaster. Space station and stuff in space already has adequate radiation protection right?
And earths atmosphere would shield from a nuclear blast in space right?

read the article. it mentions that the old concepts used weapons grade fuel, but apparently that's not actually necessary anymore.

As long as it isn't weapons grade it SHOULD be fine.

not to mention the treaty specifies WEAPONS. No country can use Nuclear or biological weapons from space. just putting some fuel rods in a rocket to go to space doesn't really violate it.

Not to mention "Rods from God" make orbital nukes a moot point anyway, and completely circumvent the treaty altogether.

>muh rods from God

post ignored

This is like so irresponsible and dangerous i'm just ugh.
I can't believe someone at NASA would propose something so awful.

What if it blows up?
What if it releases radioactive stuff around our planet?
What if it crashes on Mars irradiating it killing potential life?

There are so many things that can go wrong with nuclear weapons, and making it even worse by using them in space is utterly irresponsible and inhuman.
Once there it'll just sit there spewing radioactive fumes forever.

>Ultra Safe Nuclear Corp.

Someone really thunk hard on that one.

Hey brainlet, this is a reactor not a weapon. This is not project orion. This is NTR nuclear thermal rocket. Heat up hydrogen in a reactor, shoot hydrogen out the ass end really fast, go forward.

Would they just expel the radioactive waste into space?

This. It would be catastrophic if there was radiation in space...

Slightly radioactive, yes. It's pretty much just hydrogen that's been heated by the reactor and shot through a nozzle.

>i'm just ugh.
Very eloquent. Now, take a guess at how many nuclear explosions there have been inside our atmosphere. Then think about what is the potential damage that a tiny amount of nuclear fuel that is not even weapons grade could have. It's not even a fart. You tree huggers make me sick.

This this the one where they pack a few hundred atomic bombs into the cargo hold of the ship and drop them out the back and detonate them one after another to accelerate the ship?
That one always made me laugh.

>like
>just ugh
>so awful
A troll pretending to be a typical uneducated emotion-driven liberal? Sounds like fun. Replying as if serious:

>What if it blows up?
Things get blow'd up.
>What if it releases radioactive stuff around our planet?
Nothing of consequence to the wealthy.
>What if it crashes on Mars irradiating it killing potential life?
Who the fuck actually even begins to care?

>There are so many things that can go wrong with nuclear weapons
Why are you bringing up nuclear weapons?
>and making it even worse by using them in space
Space has more radiation jiggling through it than we're capable of generating with all of Earth's nuclear arsenal combined. Standing next to a ship's nuclear reactor would be much safer than standing next to a ship's window.
>is utterly irresponsible and inhuman
You forgot to add "in my uninformed opinion".
>Once there it'll just sit there spewing radioactive fumes forever.
It can be repurposed, or it can be buried, or it can be fired into the fucking sun. There's lots of options, actually. Space agencies tend to be practical almost to a fault, so expect the former.

Nice link. Really nailed the execution.

You must be fun at parties

autism

rods from god is an actual weapon. they used them in vietnam. they called them "lazy dog bombs" or some shit like that

Lazy dogs weren't "Rods from God", more like "rods from a bird". Rods from God are specifically kinetic weapons dropped from orbit (or rather, launched from orbit -- you at least need a deorbit burn).

The funding is only for fuel elements and a reactor, not a flight ready rocket engine. They'll make marginal progress then lose funding like most other nuclear power projects at NASA.

The treaty says no nuclear bombs in orbit, nuclear reactors in orbit are just fine.
>> NTR in atmosphere
Lol no. NTR's don't have enough thrust for that

When the reactor is finished they can put it into a parking orbit, just like all the other nuclear reactors we put into space.

>NTR's don't have enough thrust for that
NTRs have plenty of thrust for orbital launch vehicles, and their specific impulse is superior enough to give a significantly better payload, despite the somewhat poorer thrust-to-weight.

Americans worked on hydrogen NTRs as an upper stage to Saturn V, which would have doubled payloads. Russians worked on NTRs as a booster stage for ICBMs for a while (they would have used blended alcohol-ammonia propellant).

The problems were always the cost, and the mess they would have made if they blew up.

>> NTRs have plenty of thrust for orbital launch vehicles
show me an NTR with a thrust to weight ratio more than 1

At least I go to parties.

>NTRs have plenty of thrust for orbital launch vehicles
No they don't, and their Isp is not THAT much of an improvement either

Upper stage doesn't need a high thrust to weight

Also how many hundreds of millions would your NTR reactor cost, so it would need to be REUSABLE.... so we need REUSABLE chemical rockets before nuclear anything.

>show me an example of a technology that has never actually been used
Clown.

On Veeky Forums, we should have permabans for anyone who tries to argue about something without even knowing what they could learn by reading the wikipedia article on it first.
en.wikipedia.org/wiki/Nuclear_thermal_rocket
>The weight of a solid core reactor was initially thought to be its main drawback. Immediately after World War II, a complete nuclear reactor was so heavy that it was feared that solid core nuclear thermal engines would be hard-pressed to achieve a thrust-to-weight ratio of 1:1, which is needed to overcome the gravity of the Earth at launch. This problem was quickly overcome, however, and over the next twenty-five years U.S. nuclear thermal rocket designs eventually reached thrust-to-weight ratios of approximately 7:1.

Anyway, you can get higher thrust-to-weight by trading off specific impulse. Being willing to sacrifice some Isp lets you use much denser propellant, like methane or the alcohol/ammonia mix the Soviets were looking at, plus you can use tricks like thrust augmentation (dumping an oxidizer into the nozzle -- because the effluent is already very hot, it will react promptly with no ignition problems or need for a combustion chamber to use the heat of the reaction to sustain the reaction) to further boost liftoff thrust and increase overall propellant density.

It's quite workable, if not for the cost and catastrophic potential.

>hating on NTR
NTR is the best. Vanilla rockets BTFO.
>mfw NTR inevitably becomes mainstrem

>how many hundreds of millions would your NTR reactor cost, so it would need to be REUSABLE....
First of all, there's no reason to assume that NTR engines would have a unit cost of hundreds of millions of dollars. Even if they did cost that much, it doesn't follow that they would need to be reusable. Nuclear materials aren't inherently costly. There have been been some very expensive chemical rockets. Somehow NASA was okay with spending $1.5B per shuttle launch, and it was barely a heavy-lift vehicle.

>so we need REUSABLE chemical rockets before nuclear anything.
This doesn't follow at all. Why would we need reusable chemical rockets before reusable nuclear rockets? They're different challenges.

Nuclear thermal rockets are pretty well suited to reusability. For instance, the temperatures involved are considerably lower, and the vibrations should be greatly reduced thanks to the lack of combustion instability issues. A chemical rocket is a controlled explosion. A nuclear rocket is more of steam kettle. We've seen nuclear reactors that run for years and years with minimal maintenance. On top of that, the high inherent performance means that not every trick for maxing it out needs to be used: pressure feeding can be used rather than extreme high-power pumps, for instance.

Nuclear thermal rockets would be pretty well suited to a two-stage spaceplane design, which could have been achieved decades earlier than the Segway balancing trick SpaceX uses, which depends on powerful computers.

With the right motivation and some loss of nuclear inhibitions (for example, in the scenario that there had been a WW3, and radioactivity had become something that just had to be lived with), it could have happened.

>eventually reached thrust-to-weight ratios of approximately 7:1

This is still complete shit and the critical flaw in NTR hype that negates their ISP advantage.

selenianboondocks.com/2010/02/payload-fraction-example-proof/

selenianboondocks.com/author/kfsorensen/

The point about NTR's is that SpaceX(or anyone else) can't just go mass produce some cheap reactors due to the insane regulations all around nuclear anything.

Sure nuclear should be cheap & easy, but it isn't.

NASA can't produce a fucking capsule for under 20 billion dollars, it's spent the last 15 years trying to produce some replacement rocket for the Shuttle

Obviously there won't be any NTR any time soon, plus this is the same flawed thinking all over again.
It's not about increasing "efficiency", its about lowering $ per kg to orbit

>selenianboondocks.com/2010/02/payload-fraction-example-proof/
This page assumed a T:W of 3 and a specific impulse of only 850s. Meanwhile, NTR modellers are claiming T:W of over 30 with Isp over 1000s.

You're only going to be impressed by work of this quality if you're the kind of guy who doesn't dig into the details or question biases. I mean, just look at the sloppiness of it. He gives masses in "lbf".

Yes, if you assume a sufficiently shitty NTR engine (and shitty, heavy liquid hydrogen tanks), NTR will look like a bad technology, especially if you don't design around the engine. He starts with a fixed initial T:W. That's not how you design a departure stage. A rocket with high T:W engines will naturally be designed with lots of thrust to take advantage of the Oberth effect. A rocket with low T:W engines will be designed with less thrust. For an interplanetary departure you can, for instance, use a lower thrust engine to make one or two smaller boosts to an elliptical orbit before doing the final departure burn. This will only add a few days to the travel time.

On top of that, he's assuming a low delta-V of 4 km/s, which is pretty much optimal for chemical rockets, and a rather silly misuse of NTR engines. At a low delta-V, it's actually less energy efficient to use a high-Isp rocket, and the propellant savings tend to look meager.

The Apollo rocket scientists, who were no dummies, thought they could cut travel time to Mars in half with an NTR stage, even with near-term achievable designs with 1960s technology. They had certainly done this kind of napkin math, and they did it far more competently.

Do you need help figuring out which post I was replying to?