NASA-backed fusion engine could cut Mars journey to as low as 30 days.
99 replies, posted
[QUOTE=Riller;40231254]This is gonna make KSP so much easier.
[editline]10th April 2013[/editline]
Also, uh... How about slowing back down again? I'd imagine that if you're going for a landing on Mars with a speed taking you there in 30 days would be... Pretty rough.[/QUOTE]
just deploy parachutes while aerobraking, nothing could possibly go wrong!
So would this make traveling to and from mars possible then? As i understand it now, because of the conventional rockets we have to day to travel there, there would only be enough fuel to mars and not back but with this you could fit a lot more fuel in a smaller amount of space.
[QUOTE=Vilusia;40231071]Wow so does that mean it would take hours to get to the moon with this type of engine?[/QUOTE]
No, it's sort of like the ion engine in that it's most efficient on these long journeys where it has the time to build up the beneficial speed. The old Saturn V way to the moon would be much quicker
Just remember, all that built up speed to get to Mars has to be brought back down to a reasonable speed if you want to land on or orbit the planet. I could imagine 2 weeks worth of acceleration, and a week's worth of deceleration
Holy shit this is incredible!
Sounds like a pulsed-fusion [URL="http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)"]Orion drive[/URL]. I'm excited for this technology but also concerned that it might end up being restricted the way nuclear propulsion was, which is what killed Orion.
Also this will probably be the least fun way to travel imaginable, being slammed forward once every minute, but with such high Isp AND decent thrust it's worth it.
the only bad this could bring is that 30 days is still enough time for people to think Gangnam Style is comedy gold and then instead of something like one small step for man we get an idiot doing Gangnam Style on mars
Alright, to mars. We'll develop the technology to ensure survival and bring them back later.
[QUOTE=ajrhug;40233165]the only bad this could bring is that 30 days is still enough time for people to think Gangnam Style is comedy gold and then instead of something like one small step for man we get an idiot doing Gangnam Style on mars[/QUOTE]
Thirty days is not bad at all. Submarine crewmen do more than that at a time.
I've calculated that we could reach the moon right around 5 hours at those speeds, probably a little longer though due to slowing down and speeding up.
I'm curious as to what the Mars One project thinks about this. I imagine getting back off the surface of Mars would still be difficult, but once you're past that it shouldn't be too hard to come back to Earth.
[QUOTE=Rich209;40233310]I've calculated that we could reach the moon right around 5 hours at those speeds, probably a little longer though due to slowing down and speeding up.[/QUOTE]
I don't mean to pick on you specifically, but a lot of people are making back-of-the-notebook calculations that aren't accurate. A plotted course planned at ten hours for one trip does not correspond to five hours if the orbital distance is halved. That's not even getting into linear distance or gravitational effects, which both vary constantly since we're in a rotating reference plane. The amount of delta-V required and the length of the trip vary based on the start time in relation to the synodic launch window, as well as the thrust of the vessel since the impulse at each acceleration point will determine the efficiency of a Hohmann transfer or, worse and more headache-inducing to calculate, a brachistochrone.
Point is, this is not a get-somewhere-fast drive per se, it's a get-somewhere-along-a-faster-route drive. It can have a lower overall thrust and still offer a shorter travel time, because having more delta-V available means it can take faster but more costly routes between points rather than be locked into optimal Hohmann transfers like with chemical rockets that have to squeeze every last bit of impulse out of their fuel. For short missions like Earth-orbit or Earth-Moon it won't offer much of an advantage, since chemical rockets can already do those fairly efficiently and delta-V costs become exponentially greater as you try to shorten the travel time.
But for travel to other planets, this is a big first step.
A pulsed fusion engine isn't a bad idea, since we've been incapable of any kind of sustained and contained fusion reaction. Of course, we haven't yet succeeded in any kind of artificial fusion that output more energy than it took to initiate, but that's because none of the research reactors use magnetism to crush a fuel pellet, they just bombard it with massive lasers.
It could work, but I've seen a lot of supposedly revolutionary spacecraft drive proposals that never went anywhere. Remember five years ago or so when VASIMR was gonna revolutionize everything? NASA hasn't even got their tiny test motor shipped to the ISS yet.
Theoretically, is it at all possible to build an engine that requires nothing but electricity to run (no fuels/propellants/etc) for space travel?
Ion engines need a gas, this needs pellets, it seems like we're always going to be stuck having to bring extra stuff with us to go anywhere which makes it pretty much impossible to go any real distances without refuelling.
Aside from solar sails I can't think of anything - space is a vacuum so you have nothing to push against to facilitate a mechanical means of movement but maybe I'm missing something obvious
[QUOTE=Lexic;40231301]When you're half way there you rotate the rocket by 180 degrees with thrusters and turn the engines on again. I'm pretty sure that's factored into the 30 days calculation. 15 days accelerating and 15 days decelerating.[/QUOTE]
I'm pretty sure you wouldn't be accelerating for all of the fifteen days. You'd have a very short burn period to put the ship on course for mars, and then the engine would be cut off for the majority of the flight. There would also be a short burn period to enter Mars orbit, which would essentially be a deceleration.
[editline]10th April 2013[/editline]
The braking to enter Mars' atmosphere would very likely be after the craft was in a stable orbit.
[editline]10th April 2013[/editline]
[QUOTE=Zeke129;40234051]Theoretically, is it at all possible to build an engine that requires nothing but electricity to run (no fuels/propellants/etc) for space travel?
Ion engines need a gas, this needs pellets, it seems like we're always going to be stuck having to bring extra stuff with us to go anywhere which makes it pretty much impossible to go any real distances without refuelling.
Aside from solar sails I can't think of anything - space is a vacuum so you have nothing to push against to facilitate a mechanical means of movement but maybe I'm missing something obvious[/QUOTE]
Theoretically, it's possible to propel yourself through great distances in space by creating a warp bubble. However, it'd take a fuckton of electricity.
[QUOTE=catbarf;40233176]Thirty days is not bad at all. Submarine crewmen do more than that at a time.[/QUOTE]
ISS crew does more than 30 days at a time as well, which is probably more applicable here.
[QUOTE=Rich209;40233310]I've calculated that we could reach the moon right around 5 hours at those speeds, probably a little longer though due to slowing down and speeding up.[/QUOTE]
Does your calculation take into account the 3 day acceleration period?
This doesn't violate the Outer Space Treaty, right? I'd hate to see this get classed as a "nuclear weapon" and be unable to continue legally because of that.
Also am I reading this quote wrong:
[QUOTE]at a reasonable mass scale (<100 mt)[/QUOTE]
or is this ship supposed to around 100 megatons - that is, 100,000 tons?
[QUOTE=Zeke129;40234051]Theoretically, is it at all possible to build an engine that requires nothing but electricity to run (no fuels/propellants/etc) for space travel?
Ion engines need a gas, this needs pellets, it seems like we're always going to be stuck having to bring extra stuff with us to go anywhere which makes it pretty much impossible to go any real distances without refuelling.
Aside from solar sails I can't think of anything - space is a vacuum so you have nothing to push against to facilitate a mechanical means of movement but maybe I'm missing something obvious[/QUOTE]
Spacecraft rely on Newtonian physics to propel themselves, which means that it is physically impossible for a ship to propel itself without expelling some sort of propellant as reaction mass.
However, photons (light) can be used. The problem is that because they have so astronomically little mass, it takes an enormous amount of power to provide any useful thrust. You can calculate the theoretical maximum efficiency of a photon drive, and it equals out to three hundred megawatts for just one Newton of thrust, which isn't practical at all.
[QUOTE=MrBob1337;40234715]This doesn't violate the Outer Space Treaty, right? I'd hate to see this get classed as a "nuclear weapon" and be unable to continue legally because of that.
Also am I reading this quote wrong:
or is this ship supposed to around 100 megatons - that is, 100,000 tons?[/QUOTE]
100,000,000 tons
[QUOTE=MrBob1337;40234715]
Also am I reading this quote wrong:
or is this ship supposed to around 100 megatons - that is, 100,000 tons?[/QUOTE]
Small m would imply milliton, so it's saying 1/10 of a ton or 200 pounds, but that does not seem likely.
[QUOTE=Zeke129;40234051]Theoretically, is it at all possible to build an engine that requires nothing but electricity to run (no fuels/propellants/etc) for space travel?
Ion engines need a gas, this needs pellets, it seems like we're always going to be stuck having to bring extra stuff with us to go anywhere which makes it pretty much impossible to go any real distances without refuelling.
Aside from solar sails I can't think of anything - space is a vacuum so you have nothing to push against to facilitate a mechanical means of movement but maybe I'm missing something obvious[/QUOTE]
yeah you can basically use a radiator to push the spacecraft along, but it will take fucking forever to actually get any half decent speed.
[QUOTE=catbarf;40235170]Spacecraft rely on Newtonian physics to propel themselves, which means that it is physically impossible for a ship to propel itself without expelling some sort of propellant as reaction mass.
However, photons (light) can be used. The problem is that because they have so astronomically little mass, it takes an enormous amount of power to provide any useful thrust. You can calculate the theoretical maximum efficiency of a photon drive, and it equals out to three hundred megawatts for just one Newton of thrust, which isn't practical at all.[/QUOTE]
How does a photon drive compare to a solar sail when it comes to propulsion
[QUOTE=Reds;40231275]Well, time to slash NASA's budget again.[/QUOTE]
[URL="http://www.youtube.com/watch?v=dtNugAOuki8"][media]http://www.youtube.com/watch?v=dtNugAOuki8[/URL][/media]
This SORT of fits... As in cutting on science to get more defense...
[QUOTE=Zeke129;40236219]How does a photon drive compare to a solar sail when it comes to propulsion[/QUOTE]
Depends on how efficient the photon drive and solar sail material are, depends on how big the sail is, depends on how far you are from the sun, depends on how the angle of the sail can be deployed to maximize visible surface area, depends on what G-forces your sail can be built to withstand, etc, etc.
But despite both being based on light, a solar sail and a photon drive have as much to do with each other as a modern sail and a jet engine. They work on fundamentally different properties, the only real commonality is a lack of onboard reaction mass.
Fusion power is decades away though, isn't it?
But the Methane engine looks sooooo cool
[media]http://www.youtube.com/watch?v=CjoY_cSmQ70[/media]
Things like this makes aerospace nuts like myself cream everywhere
[QUOTE=Lexic;40231301]When you're half way there you rotate the rocket by 180 degrees with thrusters and turn the engines on again. I'm pretty sure that's factored into the 30 days calculation. 15 days accelerating and 15 days decelerating.[/QUOTE]
the things you learn solely from kerbal space program
Because the Moon landning did us so good
Interesting though
[QUOTE=Kendra;40232173]This [B]$600,000[/B] award will provide the proof-of-concept FDR system over the next 18 months, and a working spacecraft would be ready as soon as 2020, Pancokti predicted – but if NASA wanted to throw money at the project, this timescale could be cut.
And then the British government is going to spend around 3 million GDP on Thatcher's funeral.[/QUOTE]
They want to be sure to seal the tomb just in case the dead ever rise.
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