Nuclear Thermal Rocket (NTR)

Is this even a good idea?

To start with, storing super-cooled liquid hydrogen for extended periods of time in deep space seems difficult and wasteful.

Secondly, using such risky and difficult technology to dramatically increase the DeltaV budget of a mission, and then blowing all that extra dV to cut the time needed to get to Mars instead of sending a bigger payload, seems like a huge waste.

Nobody actually believes humans can realistically ever return from Mars. It is certainly going to be a one-way trip for the first decades. Who cares if they get blasted with radiation for 4.5 months extra? The increase in cancer rates is miniscule.

Other urls found in this thread:

phy6.org/stargaze/Smars1.htm
en.wikipedia.org/wiki/Lunar_space_elevator
youtube.com/watch?v=5bDWHTAOKNA&index=115&list=PLVV0r6CmEsFzDA6mtmKQEgWfcIu49J4nN
myredditvideos.com/
twitter.com/SFWRedditVideos

>Nobody actually believes humans can realistically ever return from Mars
Try again, kid.

Instead of rockets NASA should be figuring out how to do the important stuff like grow food for the colonists and automated equipment to run the colony. Heck they even need a gps or an alternative tracking system.

>Nobody actually believes humans can realistically ever return from Mars.

Zip wire you absolute fucking brainlet

NASA will never do any practical helpful work

>bringing nerva back in a world of MUH DANGERAS NUKELAR REFRIGERATORS!
Good luck.

The Russians and the Chinese are already on it.
There is a space race brewing.

NASA doesn't need to do that, for there's contractors doing that RnD for them as we speak
having one entity do everything is fucking retarded

Russia has no money, Chinese research is all fake.

that only applies to nations that have to deal with PR, and the companies under their jurisdiction
everyone else gives negative fucks and will do as they please

Time in space matters. You have to carry food, water, and oxygen for the additional time. And a faster transit minimizes exposure to solar flares. Not a matter of statistical increase in cancer. One good proton storm and you're dead.

Regardless of how you decide to use your higher Isp, without nuclear propulsion, spaceflight will never progress beyond the over-Niagara-in-a-barrel stage. Chemical rockets are adequate for going into orbit, marginal for travel to the moon, really stretching it to reach Mars. Anything further demands insane mass ratios.
The minimum energy orbit from LEO to Deimos requires 5.25 km/sec and 259 days. Plus whatever it takes to lift from the Earth and land on Mars.
Going from LEO to a closed orbit around Jupiter takes 8.149 km/sec and 2.7 years. One way.

Reminder. If your chemical fuels are H2 and O2, you're going to be lugging around cryogenics anyway.

this x1000
they're doing some of that right now, but if they cut rocket design from their budget entirely they could supercharge those areas

do the research needed to make a mars colony, let private space do the launching of probes and hardware. saves a ton of money too

Their space launch program is in absolute shambles and should be taken out back and shot.. but NASA's actual R&D teams and basic science programs are top notch m8.
NASA should have never subcontracted, should have just made JPL what SpaceX/BlueOrigin/Cygnus is back in the 60's.

>
China using camera footage of water tank training does not make their entire (military) space program fake.
Russia does indeed have money problems, but they still pull shit off.
Space Race 2.0 is go!

>Nobody actually believes humans can realistically ever return from Mars. It is certainly going to be a one-way trip for the first decades.

Wrong, reusability is key to colonization of Mars. That means spaceships traveling to Mars, then refueling and traveling back to Earth to be used again. You may as well put some people on the return trip, too.

Electromagnetic acceleration off the moon + a burn in LEO would be ample for sending men to the outer solar system.

Obviously there is no reason to send people out there before you have a bustling colony on the moon & mars & mercury

Yea, but I'm not sure if they are allowed to do that, to just build everything inside, buying the raw materials, instead of spending billions of contractors.

>making a lunar launch loop, combined with water ice cracking
the way to do it
not to mention you can make a lunar space elevator using only kevlar

Boogeymen ain't gonna cut it. Russian space program is a joke and the chinese are stuck copying 70's ussr tech. If you are waiting for space race better don't look for it at national level.
NTR is doomed. Far too many issues for mere doubling of isp.

It is absolutely necessary to have NTP engines to get to Mars efficiently. Chemical rockets do not have the specific impulse and ion thrusters don’t have the total thrust.

>space race with russia and china
we're pretty much past government space races, right now it's all on private industry
get the cost to orbit cheap enough and other industries will take note and start considering space much more seriously

problem is, with nasa so preoccupied with SLS, they don't have the money to do really important stuff like doing asteroid surveys or testing lunar infrastructure designs, which puts more risk on private industry

What issues? NERVA worked well.

So BFR is doomed to fail?

"efficiently" is relative, be specific

Until you have space travel brought down to a fraction of the fuel cost, then you can't talk about "efficiently", there is vast cost savings that can be made

Handling and cost. Nowhere near worth it for what it offers. It's a dead end.

The BFR will be effective because of how much payload it can carry to the Martian surface. It's like a space fairing cargo freighter, in the sense that it's not the best way to get to Mars but the amount of cargo it can carry outweighs it's lack of efficiency. Also, the fact that it's not very efficient doesn't mean it isn't quick; the time of the quickest possible journey to Mars for a BFR has been estimated as around 3 months and because of it's larger size it will be effected less by cosmic radiation than other smaller spacecraft.

>3 months
Hmmmm not even a ULA shill but that is delusional, probes take a year to get there.

NO, you cannot make a Lunar space elevator.
The gravity well may be shallow but it only rotates every 28 days.
Think!

Probes take 7/10ths of a year, minimum energy orbit. Semi-major axis somewhere between Earth's and Mars'; duration somewhere between half an Earth year and half a Mars year.
>phy6.org/stargaze/Smars1.htm

That's because they use tiny thrusters and gravity boosts to move, the BFR has 4 vacuum optimised Raptor engines which each produce around 70% of an F1 engine's thrust. What I've mentioned isn't a likely scenario but the perfect one with all the variables correctly aligned e.g. Optimum orbit, full tank of fuel.etc.

>Mars colony

good thing a lunar space elevator doesn't work that way
en.wikipedia.org/wiki/Lunar_space_elevator

youtube.com/watch?v=5bDWHTAOKNA&index=115&list=PLVV0r6CmEsFzDA6mtmKQEgWfcIu49J4nN

Nuclear Rockets are dead. The Hippies and budget hawks will never let them fly. The costs both real and imagined are too high for anything more than RTGs to ever fly. NASA is in denial over this so they still shell out a few million to various groups every few years to "develop" nuclear propulsion. It always ends the same way. Some research papers and power points about how great their Nuclear Rockets would be if we built them but no actual progress having been accomplished.

>Secondly, using such risky and difficult technology to dramatically increase the DeltaV budget of a mission, and then blowing all that extra dV to cut the time needed to get to Mars instead of sending a bigger payload, seems like a huge waste.
But that's the point.
You could send a bigger payload, or get there faster. Both options become available.

oh yes oh yes oh yes
nuclear pulse propulsion PLEEASSSEE

>>Is this even a good idea?
user this is the best idea ever and we should do it before the commies do it.

The Chinese space program to date has been entirely Soviet retreads.

Why should anyone be impressed with Chinese Soyuz visiting Chinese Salyut in the 2010s, or the better part of the 2020s being scheduled to build Chinese Mir?

Hadn't heard of this one.
Still a massive project, but much better than what I'd been thinking of.

I dunno about the hippies, but the last few weeks seem to show the "budget hawks" are the corpses.
GOP has totally abandoned fiscal responsibility.

God I fucking hate hippies. Pieces of shit that keep us using an extremely safe and efficient technology because they are scared of muh radiation death rays. Just round them up and ship them to a reserve where they can smoke weed and drum circle all day and let the rest of us get on with it.

do you guys really think that we can colonize mars?

what energy becomes too expensive in the coming decades as we run out of fossil fuels? or rare earth metals?

won't one of these factors limit our technological advancement?

Depends on if we don't destroy each other or civilization faces decline. Space colonization requires an opportunistic future. If we feel like we need to spend more on security, welfare, etc. then we won't. That is a real possibility. Realistically, only Elon Musk and SpaceX have a viable strategy to colonize Mars. Second might be China, but there own moon missions are decades out and it serves only for domestic political achievements. USA and Russia are hampered by domestic political squabbles that prohibits efficient planning that could it.

I really wouldn't be concerned about energy / rare earths. Renewables essentially cap the cost of energy to $200 / barrel which would change are way of life, but for space, it's nothing. There are different way to get around rare earths for their use.

>as we run out of fossil fuels? or rare earth metals?

If we get fusion working none of that matters. We can make fossil fuel out of carbon dioxide and water, using it as a store of electrical energy from the reactor. Rare earth metals can be had by the gigatonne from any near earth asteroid, which will be accessible with fusion rockets. We can then build as many orbital habitats as we please, each little asteroid can have one. We can also colonize any planet.

as space elevators go, it's way more feasible because thousands of miles of kevlar is much easier than thousands of miles of maybe graphene i dunno

Yes, absolutely.

>If we get fusion working

This should be forgotten already.

It'll come if it comes, but probably not in any compact enough form for reasonable spacecraft application within any reasonable timeframe - less than hundred years.

It would make it far more cheaper and accessible, allowing the colonization of our solar system etc to happen at a much much accelerated pace. But it's not needed.

Sure SpaceX and others would welcome and buy the shit out of any companies that come up with a way to make a practical fusion rocket. But they don't give a flying fuck if a fusion rocket will never be realized. They'll still aim to do everything you mentioned, and likely will at some point and succeed in making it extremely profitable. And if fission rockets can't be used anywhere near earth, then they'll do it somewhere else where all the regulations and political crap won't come in their way

>Renewables essentially cap the cost of energy to $200 / barrel

can you explain why that is?

what about all the machines that run on oil? we couldn't possibly convert them all to electric.

Name one.

Wrong. They still need to get everything up there. If they develop tech for living up there first that technology will be out of date by the time tockets are then developed.

NASA should just stop trying to build rockets, they are obviously absoluetely bad at it, both Blue Origin and SpaceX are outperforming them with a much smaller budget. NASA is just embarassing itself at this point.

Methlox rockets like Blue Origin and SpaceX are developing can go to Mars and back without issues. There is absoluetely no need for a politically difficult propellant that holds no advantage whatsoever to methlox.

What piece of machinery can we not convert to electric?

If there even is such a thing, we can always make oil from electricity.

Netorare is always a good idea, user

how so? the private space race is already heating up extremely fast. assuming BFR works out and becomes a real heavy lift work horse that makes space infrastructure FAR cheaper and more feasible. Nasa's learnings from the ISS can apply to pretty much any orbital installation a private company may build.

nasa really doesn't need to work on rockets, they actually kind of bad at it these days anyway

>One good proton storm and you're dead.

There are various strategies for dealing with this. Non-rotating water tanks as a shell, with a rotating habitat inside. That's the simplest method. There's been some work lately on magnetic shields augmented with plasma bubbles, and it appears quite effective in testing and modelling.

rip humanity

I'm aware of those strategies. I probably read the original sources before you did.
The non-rotating shell around a rotating habitat is good -- for a habitat.
This discussing is about minimizing transit time between planets.
A ship cannot afford all that parasitic mass.

Magnetic shields and plasma bubbles don't work yet. And when they do (and I hope they do), they'll have to be powered. Heavily! Which brings us back to nuclear energy.

As of the moment, the only way to be (relatively) safe in space is to spend as little time as possible there. As I said, when mass doesn't matter (an O'Neill) shielding becomes feasible. Otherwise, try to be inside the van Allens or under a few meters of dirt when a storm hit.

Addendum: When I said "probably before you did" I was referring to the space colonization/power satellite ideas in the '60s.
"The High Frontier."
We've learned more now. The brave pioneers setting off for the asteroids in their solar-powered ion-drive privately-owned spacecraft would likely be brain dead before reaching Ceres. Meteorites are not the hazard once feared but the early prophets underestimated radiation.

>NTR
What's the meaning of this?

nuclear thermal rocket

>What is logistics?
You'd expect a launch from the unstable surface of mars to go smoothly?

>muh colony
no reason