NASA's Proposed Plasma Rocket Would Get Us to Mars in 2 Months (gizmodo.com) 176
Last week, NASA announced it is working with a technology development company on a new propulsion system that could transport humans to Mars in only two months -- down from the current nine month journey required to reach the Red Planet. Gizmodo reports: NASA's Innovative Advanced Concepts (NIAC) program recently selected six promising projects for additional funding and development, allowing them to graduate to the second stage of development. The new "science fiction-like concepts," as described by John Nelson, NIAC program executive at NASA, include a lunar railway system and fluid-based telescopes, as well as a pulsed plasma rocket.
The potentially groundbreaking propulsion system is being developed by Arizona-based Howe Industries. To reach high velocities within a shorter period of time, the pulsed plasma rocket would use nuclear fission -- the release of energy from atoms splitting apart -- to generate packets of plasma for thrust. It would essentially produce a controlled jet of plasma to help propel the rocket through space. Using the new propulsion system, and in terms of thrust, the rocket could potentially generate up to 22,481 pounds of force (100,000 Newtons) with a specific impulse (Isp) of 5,000 seconds, for remarkably high fuel efficiency. [...]
The pulsed plasma rocket would also be capable of carrying much heavier spacecraft, which can be then equipped with shielding against galactic cosmic rays for the crew on board. Phase 2 of NIAC is focused on assessing the neutronics of the system (how the motion of the spacecraft interacts with the plasma), designing the spacecraft, power system, and necessary subsystems, analyzing the magnetic nozzle capabilities, and determining trajectories and benefits of the pulsed plasma rocket, according to NASA.
The potentially groundbreaking propulsion system is being developed by Arizona-based Howe Industries. To reach high velocities within a shorter period of time, the pulsed plasma rocket would use nuclear fission -- the release of energy from atoms splitting apart -- to generate packets of plasma for thrust. It would essentially produce a controlled jet of plasma to help propel the rocket through space. Using the new propulsion system, and in terms of thrust, the rocket could potentially generate up to 22,481 pounds of force (100,000 Newtons) with a specific impulse (Isp) of 5,000 seconds, for remarkably high fuel efficiency. [...]
The pulsed plasma rocket would also be capable of carrying much heavier spacecraft, which can be then equipped with shielding against galactic cosmic rays for the crew on board. Phase 2 of NIAC is focused on assessing the neutronics of the system (how the motion of the spacecraft interacts with the plasma), designing the spacecraft, power system, and necessary subsystems, analyzing the magnetic nozzle capabilities, and determining trajectories and benefits of the pulsed plasma rocket, according to NASA.
Aim lower first? (Score:3)
Re:Aim lower first? (Score:5, Insightful)
It doesn't really matter if it takes a robot 9 months or even longer to get there. Primary concern is fuel efficiency and the amount of mass that can be delivered, because robots don't mind waiting, don't need 9 months of food and oxygen supplies etc.
Cutting the transit time for humans by 7 months would have a huge impact on both the wellbeing of the humans and on the time they could spend on and around Mars, since 14 months of supplies that would have been consumed on the journey are now available for that.
Re:Aim lower first? (Score:5, Informative)
His point was "prove it works on robots before you send humans to their tragic death dying slowly in space and set this technology back decades".
Re: Aim lower first? (Score:2)
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You know, aside from films like "The Martian" and its ideas about human tethered orbital rendezvous...anything that goes wrong on one of these trips is most likely a relatively rapid death sentence and even if not, a slow wasting death sentence. Either we're going to get there or not, but the concept of making it safe is going to make sure the answer is 'not'.
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ok. But define 'test'? How do we make sure a rocket with decent lsp is restartable from Martian orbit, which I think is the biggest risk - something sitting in a vacuum alternatively at close to absolute zero and ~150C working properly when it is attempted to be restarted, months or years later. I suppose you could loft it into Earth orbit and let it sit out there for a commensurate length of time.
Come to think of it, radiating off the waste heat from a nuclear reactor in a vacuum sounds like an interest
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How do we make sure a rocket with decent lsp is restartable from Martian orbit?
By sending a robotic mission to Mars and trying it.
This can be generalized: The best way to find out if you can do X is to try to do X.
radiating off the waste heat from a nuclear reactor in a vacuum sounds like an interesting problem.
Build a big panel. Put a shiny mirror on the sunny side, and coat it with Vantablack [wikipedia.org] on the dark side.
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I'd suggest a craft in Mars orbit would be very hard to get to, to figure out why it didn't work.
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I'd suggest a craft in Mars orbit would be very hard to get to, to figure out why it didn't work.
You use sensors and cameras, just like you do in Earth orbit.
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Presuming you have sensors in the right places and the comms infrastructure works back a hundred million miles.
I work for a testing organization. We have special rigs for common tests we do on systems, which ultimately result in reports that get delivered to Congress. But no one pretends we have enough sensors to obviate forensic examination of systems in the event of failure - or even not-failure. I've worked in various associated roles - the proponent of the system, the testing organization, and 'lab b
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Your second paragraph is my issue with the whole thing. If we aren't ready for that, we aren't ready for planetary exploration. Shit's gonna happen, and probably a lot judging by our issues with landing on Mars over the years. It's a relatively hospitable environment to land on, and yet lots of the probes sent have failed.
Ironically Mars is a great candidate for a space elevator to eliminate most of those problems.
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Yup. And we all know NASA is famous for not doing any testing. Bunch of cowboys.
Re: Aim lower first? (Score:2)
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But it matters to the research and operation teams whether their downtime is two months or nine months. Such a reduction could alter the economics of a robotic exploration program, which would surely be a prelude to a manned mission. So the robotic program could both provide input into planning of the manned mission while proving the propulsion technology is reliable enough to be man-rated.
Current concepts for a manned Mars missions would last 22 months, 21 of which would be spent in transit and one on Ma
Re:Aim lower first? (Score:4, Informative)
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And the "human" bit is to keep Congress happy. Yes, they do control their funding but to go up to Congress and ask solely for month for bot missions means they get nothing.
And Now (Score:2, Funny)
Let's switch to Slashdot, where a guy who thinks he's an engineer because he watched a Mythbusters re-run once will tell us all why it will never work.
Bob?
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It will work, the science and engineering aspect is solid (see NERVA) .. but NASA's involvement jeopardizes it.
Re:And Now (Score:5, Informative)
Oooh ooh! I can do this!!
Due to the nuclear nonproliferation treaty, and the space nuclear treaty, the delivery of nuclear materials into orbit, or the utilization of active nuclear energy sources (like fusion detonations, which is what this would be) are either "Highly Controlled" or "Not Permitted" via international treaties.
This is because, while the Outer Space Treaty is mainly about the deployment, use and operation of nuclear weapons in space, one of its provisions includes the "contamination" of space, and the liability for damages caused by the operation of spacecraft against other spacecraft.
Regular use of a fusion rocket based system, would leave trails of highly energetic particle radiation, and high-speed massed particles, floating around in interplanetary space (in useful to traverse regions, because the region is-- USEFUL TO TRAVERSE), posing both liability considerations for other ship crews (you are responsible for the waste that gives them multiple soft-tissue cancers on their way to/from other celestial bodies!) as well as for other, later ship systems (Bigger, heavier shielding required, to deal with the increasing levels of energetic particle waste over time, should this mode of travel become in any way regular or ordinary.)
If there is one thing that bureaucracies hate more than anything else, it is legal responsibilities, and risks.
Unless there is an iron-clad way to completely obviate the united states from any culpability for later astronauts developing cancer in space from exposure to past missions' emissions, the committees full of committees will pass this idea around endlessly, ensuring it never actually dies, but also never actually gets greenlit.
Oh-- Did you want a technological reason?
Uhm.... Hmm...
Putting a really big fusion rocket ship into orbit requires construction in orbit, due to the astounding costs required to lift the necessary building materials from the planet's surface. Putting whole assemblies up there would have to be done as sub-assemblies, because they would have to fit on existing heavy-lift rockets to get up there.
Re: And Now (Score:2)
Re: And Now (Score:5, Informative)
No. It covers contamination as well.
Principle 3, page 49.
https://www.unoosa.org/pdf/pub... [unoosa.org]
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Principle 3.2(a):
2. Nuclear reactors
(a) Nuclear reactors may be operated:
(i) On interplanetary missions
Re: And Now (Score:2)
Bzzzt.
No, do not skip the pertinent section above it like a cherry picking politician.
Here, let me blockquote it (and bold it) for you.
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Besides which, if a nation is not a signatory of a treaty, it's not going to be bound by its provisions regardless of what the UN general assembly says. No nation agreed to let the UN legislate for it.
Otherwise Israel would have evacuated Gaza and stopped the ethnic cleansing long ago. Same mechanism - General Assembly resolution. They have about the compelling power of a petition to your local government.
Got one! (Score:2)
"Unless there is an iron-clad way to completely obviate the united states from any culpability for later astronauts developing cancer in space from exposure to past missions' emissions..."
We wipe out the species through climate change...famine or through climate change...global unrest...nuclear war...famine. Both seem like likely paths, given continuation of current behavior.
No future astronauts, no problem!
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There is no "contamination of space". The exhaust is much faster than escape velocity from the solar system. Thousands of kilometers per second.
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There is no "contamination of space". The exhaust is much faster than escape velocity from the solar system. Thousands of kilometers per second.
You're forgetting that anything that is in any way nuclear is so evil that even the craziest opposing idea has to be given more credence. Right now, for example, we might be hearing that nuclear fission was invented by Jews.
Re:And Now (Score:5, Insightful)
1) There are no "launch windows" with nuclear propulsion. You're not doing Hohmann transfers anymore.
2) You couldn't contaminate the next spaceship from millions of kilometers away if you literally tried to do so. You're not going to be detectable above the (already significant) background radiation, by orders of magnitude.
3) "Contamination" implies something that persists. Not something that buggers off out of the solar system at a speed of thousands of kilometers per second. Distance from Earth to Pluto in just a week or two.
Start understanding the mind-boggling vastness of space and the already immense radiation load therein.
Re: And Now (Score:2)
Not to mention that there would be no such problems just like atom bombs and nuclear reactors leave no chemtrails as long as fission is complete.
And then there is also the fact that the Universe isnâ(TM)t static. Even if you launch hours away, earth and everything else will have moved.
Re: And Now (Score:2)
This is true, but emissions are not tight laser like beams. They are exhaust cones. As long as ships are intersecting the exhaust cones of ships ahead of them (the exhaust is much faster than the trailing ships, and will intercept as distance increases. Energy exposure per cone will fall off at the inverse cube, but if you have enough ships in front of you, that wont matter. Enough stray plume photons and hard neutrons will cause daughter particle accumulation in your shielding, and secondary local decay wi
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And then there is also the fact that the Universe isn’t static.
you’ve just hurt the Electric Universe peoples feelings.
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By the time we arrive into the future where 'thousands' of spaceships are getting launched in a window, we may very well have newer transport technologies that make this one moot.
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That's not how Hohmann transfers work [ottisoft.com]. Just stop. And a minimum energy transfer to Mars is 9 months anyway, not 6.
Get this through your head: There Are No 'Launch Windows' With Nuclear Propulsion. You don't leave a craft that can travel to Mars a matter of months sitting idle rusting away rather than repeate
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Ok, I am going to try and be calm.
Firstly-- again-- there are things like maintenance costs, the costs associated with orbiting the fuel to put into the rocket, the time needed to load and unload the rocket, and other factors that you are just handwaving.
Neutron induced embrittlement in your reaction tube is NOT something you want to have cause a catastrophic failure, in mid flight, because you simply couldnt wait a few months.
https://en.wikipedia.org/wiki/... [wikipedia.org]
If you want your rocket to FUCKING EXPLODE in fl
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Consider more, the Los Angeles express way.
Honestly, that seems like a stupid thing to consider right now. There are no cities on Mars, and this technology will not cause there to be.
There is no reason for numerous launches with this technology because it allows for much bigger vehicles.
One "tell" that you're full of shit, even before reading the article and noting the actual details of what the technology is and what needs exist, is where you say:
MUUUUUUUUUUUCH bigger than you are imagining
Try to include some critical thinking, instead of just, "YER RONG THARFOUR YOU CANNUT IMIGINE!"
Re: And Now (Score:2)
oh kaayy..
This particular argument you just made, is similar to naysaying about commercial air travel 150ish years ago.
At the prepandemic peak, there were about 20,000 flights per day. It is currently about 8000 flights per day.
Improvements in ability to transport humans and cargo with airplanes, caused humans to transport more humans and cargo that way.
There is a desire to colonize mars, that is currently not realizable, because the costs of establishing one are too high.
One of the significant cost centers
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Re: And Now (Score:2)
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Putting a really big fusion rocket ship into orbit requires construction in orbit, due to the astounding costs required to lift the necessary building materials from the planet's surface. Putting whole assemblies up there would have to be done as sub-assemblies, because they would have to fit on existing heavy-lift rockets to get up there.
You mean like the ISS? And MIR? We've done that already. With fast transportation, the system is likely useful for multiple journeys. It can transport enough weight that it can have a separate landing module. This brings up a bigger question, though, and I hope it's a question that has been asked. The question is, if you're going to Mars, there is the possibility of life there. We don't have a solid answer to that question right now. Does this need to be a one-way journey, so there isn't some huge global di
Re: And Now (Score:2)
No, I mean something a lot bigger.
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No, I mean something a lot bigger.
Relax. Nobody is going to want to put your head into orbit.
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Cute.
No, I mean the cost of this thing, means that in order to make it profitable, it has to be rather large, and haul a lot of cargo.
It's comparable to a nuclear reactor that way. This expense-to-profit ratio is precisely the reason why small nuclear reactors are not, and are never likely to be, economical to build, operate, or service.
https://www.ewg.org/news-insig... [ewg.org]
You need to move a very very large amount of cargo to mars, in order to justify the very large expense of constructing the rocket in orbit.
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Re: And Now (Score:2)
I am going to assume you mean me, and are referring to a particularly dumb Voyager episode, involving the dumping of 'antimatter waste' into space.
That whole series is especially dumb, but that episode is even worse. Antimatter waste is gamma ray photons. If you can catch those in a tanker, you dont need to dump them. Your energy harvest ratio is 100%.
Lol
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Re: And Now (Score:2)
Lol, no, I have only seen it once.
It was just memorably painful.
For anyone who cares about how it actually works.. (Score:5, Informative)
... as opposed to just random ignorant press fluff, here you go [sciencedirectassets.com].
TL/DR: it's a gun that shoots fission plasma like little nuclear bombs. A 2,2kg projectile containing low-enriched uranium (LEU) and a moderator is fired (once per second) by a coilgun through a a flared 522kg 33cm-long LEU barrel (with the barrel flaring out in a HEU section at the base) at 1600 m/s (requiring 5MW of power), where it hits criticality. By a third of the way through the barrel its interior is already 1eV / 11605K, then is boosted to 500 eV by the HEU section as it leaves the barrel into a parabolic magnetic nozzle to direct the plasma. The fact that the projectiles move through in pulses makes it easier to cool the barrel, given that the thermal power present in the first third of the barrel is 5,4TW, and in the latter section, a peak of 46TW; obviously you're not going to withstand that continuously! 1% of the power from the explosion is recovered via coils, returning 29MW to the system, to power the gun and any other spacecraft needs. The result - 100kN of thrust at 5000 sec Isp, would be enough to lift 10 tonnes of mass from the surface of the Earth (not that you'd use it on the surface), and has a propellant efficiency 14x that of Starship's Raptor engines.
Obviously, this rocket is dirty, but almost everything from the explosion will have a velocity higher than the escape velocity of the solar system, so so long as you're not pointing it directly at Earth, it doesn't matter. Not that one engine firing in the direction of Earth would matter all that much anyway, but...
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... so long as you're not pointing it directly at Earth, it doesn't matter.
Deceleration means you're turning the hull into a radioactive nightmare you do not want to meet on a bad day.
But let's not worry about that because, in all fairness, Mars *is* a radioactive hellhole and a little more expsoure isn't going to add much to the drama
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Again, an Aldrin Cycler is the ideal use for this engine.
Because it does NOT decelerate. It rendezvous with the target body, makes a slingshot manouver, then continues BACK to Earth.
It's a cargo hauler on a continuous, noninterrupted crossing orbit.
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Aldrin cyclers make no sense as cargo haulers. They don't save you dV or time - they cost you more dV and time to dock with them vs. taking an optimal direct trajectory. The point of an Aldrin cycler is that you can have a big spacecraft with tons of radiation shielding and nice facilities for humans on their long trip to Mars, which you don't have to loft every single trip. But it provides no advantages for cargo, only the aforementioned disadvantages.
And Aldrin cyclers are premised on long transit times.
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To be fair, you don't decelerate pointing directly at a planet (if you even decelerate by rocket power at all, rather than aerocapture). The deceleration burn is parallel to the planet. You don't want to fall straight down onto it.
Though I mean... I guess with this sort of thrust to weight ratio, you *could* design a spacecraft where this could give you powered flight all the way to the surface ;) Still, pretty wasteful; nuclear fuel doesn't grow on trees.
Then again, if you built the craft with enough th
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The deceleration burn is parallel to the planet. You don't want to fall straight down onto it.
Not the point. The hull will be travelling through a nice cloud of high energy pollution, collecting fleas/daughters and various other bits of radioactive detritus, en route. You really don't want to be anywhere near that thing without a serious amount of shielding after the trip.
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Do you understand what the word "parallel" means (aka, "not entering the planet"), and that these particles are rapidly en route to escape the solar system at several thousand kilometers per second? You're not catching up with them. Ever.
It's just nonsense. It's not even a highly collimated stream, and even if it were, you could just angle it slightly off-axis. It's moving away from you at relativistic speeds, and it's versus an environment that's already awash in radiation.
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What? No. That's not how relativity works. Not even fancy relativity, good old Galilean relativity. Do not learn physics from Aristotle.
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I found this pdf version [sciencedirectassets.com] of that paper.
Re:For anyone who cares about how it actually work (Score:4, Interesting)
(However, if one is wiling to envision some very unlikely collaborative space futurism magical thinking)
Construction of a single, VERY VERY LARGE spacecraft, like an Aldrin Cycler, could be inserted into a "Permanent" resonant crossing orbit between two (or more, but the math gets trickier) celestial bodies.
Once in this orbit, it no longer needs its engines, except to perform corrections.
This spacecraft is essentially a humongous space station, with hangars, docking arms, and other futuristic whizbangery, and less capable ships rendezvous with it, dock to it, and get carried out of system at a very high speed by it. It arrives in the target system, where they disembark and go about their actual business.
In that hypothetical, there is only need for a SINGLE vessel with such engines, so blasting the space behind the vessel does not carry such considerations (and carrying the requisite shielding to not give all the crew mega-cancer is realistic. It has the necessary mass to not get ripped apart on an orbit correction burn, with that kind of mass attached, and can have engines big enough to boost/move that kind of mass.)
BUUUUUUT-- do you really think we would be *ABLE* to cooperate, internationally, long enough to actually BUILD and DEPLOY an Aldrin Cycler?
I don't really think so.
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You don't seem to understand a basic point about an Aldrin Cycler.
Namely, it doesn't save any fuel. The reason it doesn't save any fuel is because you have to rendezvous with it, expending all that delta V. Now, that doesn't make a cycler useless. It's still quite useful in that the passengers don't have to rendezvous with massive spacecraft capable of supporting them for the entire trip. They just need to use a spacecraft that has them, plus all the consumables needed for their trip and don't need to have
Re: For anyone who cares about how it actually wor (Score:2)
That assumes you let the cycler go past, and try to then catch up with it.
Rather than being in front of it, just after it slows down from its interaction with earth's gravity well. (Escape phase)
Your ship needs to be designed to get netted, then towed up. (Not go RealRealFast to 'catch up' so it can align gimbles)
Multilayered catch net concepts have been designed/proposed for this purpose.
The net CANNOT pull the captured spacecraft to its own velocity 'instantly', it would liquefy the crew, and crush the sh
Re: For anyone who cares about how it actually wo (Score:2)
I should probably clarify.
Consider, the cycler has a very long, well built skyhook 'tail'.
Instead of just naked hooks, redundant nets are strung between these rails, attached to the hooks.
You ship is super slow compared to the cycler.
You use normal burns, ahead of schedule, to be in the capture alignment path of the cycler.
The cycler very rapidly gains on your very slow vessel, and you get caught by the netting on the rails trailing behind.
Instead of going instantly taut, the hooks on the rail system allow
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It saves fuel because you don't have to accelerate and decelerate your long-term living quarters.
It doesn't save delta V. Unless you consider that you'd probably have to go faster if you had to accelerate and decelerate your living quarters, in which case it saves delta V too.
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A conventional cycler implies traditional rocket engines, and thus tries to conserve burn as much as is possible. This is why the orbit is as circular as possible.
With a fusion torch rocket, the cycler could be on a much more elliptical orbit, with more direct paths.
(More realistically, due to the same confluences of orbital period between earth and mars that promote good transit windows, the cycler would have trips that take longer (A LOOOOT longer), and trips that take shorter (well within the time budge
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You don't have to be that far off-axis / distance before you've diffused to less than the (already significant) space background radiation. Remember that the distances we're talking about here are tens of millions of kilometers. Kinda hard to irradiate people from those distances even if you tried.
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Again, consider more "Multiple craft on the same entry window", because orbital alignment waits for nobody-- and less "We can go whenever, and can spread them out."
The premise was "If this gets in any way regular or ordinary."
The thinking you have, is exactly the kind of thinking industrialists in the 19th century had concerning CO2 emissions.
You need to think about much later.
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orbital alignment waits for nobody
If you have 50 kNs/kg of specific impulse and 2 month transit time, *why the hell* would you care about "orbital alignment"? With that you can fly almost any time you want!
Re: For anyone who cares about how it actually wor (Score:5, Insightful)
You simply do not understand orbital dynamics. You're referring to Hohmann Transfers. They're irrelevant if you're applying extra dV, which is what this entire article is about. There are no "windows" with nuclear propulsion. Nobody is going to leave the capital investment of a spacecraft that can do such quick transfers sitting idle waiting for a "window" when they can head there and back repeatedly in the same timeperiod.
Furthermore, even if we pretended it was just a few days apart (aka, even if we pretend nonsense) - On, say, a 200m km trip in 75 days, 2 days apart is over 5 million kilometers distance. You'd struggle to see a high powered laser pointed right at you from that distance. You're not going to increase radiation over background. Period. Even if the stream was super-collimated, which it isn't even remotely.
It's nonsense. Just stop.
Re: For anyone who cares about how it actually wo (Score:2)
Economics, do you speak it?
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Yes, and you clearly don't.
Your costs are in your spacecraft, not your fuel. You're not going to leave it sitting idle for years waiting for a "window" to make a single delivery when you could make ten deliveries in that same timeperiod. Doing the former would mean increasing your capital costs by an order o
Re: For anyone who cares about how it actually wo (Score:2)
And how, exactly, are you getting 2x or more fuel into orbit? It's not a fusion rocket. ;)
additionally, have you factored the weight and storage space lost on the fusion rocket, to make room for 2x the fuel, and then recalculated the costs for your longer burn time against maintenance costs of your rocket tube, radiation shields, and lost capital recoupment rate?
Better charge a lot more for that out of window launch!
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It's a fission rocket - bloody close enough.
It's an ISP of 5000, it doesn't matter.
If you want to get there quickly, you're always loading it fully with fuel. The only difference is in the transfer time. All of them are "very fast", just varying degrees of "very fast".
It's like trying to say we should only fly airplanes on the couple days per year when the jet str
Re: For anyone who cares about how it actually wo (Score:2)
You are making dangerously false assumptions.
1) that the fuel costs 0$ to orbit, and that there are no economic constraints on building a fusion rocket that sacrifices cargo space for the additional fuel.
2) you are assuming that the only constraint against the window requirement is crew health. (As measured as time in transit) This is not true, because fuel does not cost 0$ to orbit, and getting the most cargo to and from the target planets with the least fuel consumed, will require-- USING SUCH TRANSFERS.
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Re: For anyone who cares about how it actually wo (Score:2)
Consider the logistical mindset that causes 'we havent replaced the computers that run the newyork metro subway system for 20+years, and we still run os/2'
Or, 'why japan did not shut down fukushima daiichi for repairs'
Now, apply that to a fusion rocket that costs more than china's GDP.
This rocket irradiates the shit out of its reaction tube. (Several Tw of energy per pulse) The longer you fire it, the more radioactivity induced embrittlement from neutron capture events it will experience.
Replacing the react
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Your response tells me you're ignorant and needlessly combative.
Minimum transit time matters far more than the schedule because space is a very hostile environment, especially for humans.
Kept saying that since Elon spoke about Mars. (Score:2)
Musk is doing a lot of great things, but my opinion is that he has some huge blindsights.
Wanting to go to Mars using chemical propulsion instead of nuclear is one.
I cannot fathom how any intelligent person would do that.
Unless...It is just a red herring to promote his business.
Re: Kept saying that since Elon spoke about Mars. (Score:2)
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Realistically, the key enabler of all this stuff is getting mass into orbit, and that can only be done with chemical rockets for the foreseeable future. That is what Starship is, and I'm sure Elon/SpaceX would have no problem if Starship being able to lob tonnes into orbit for cheap enables the development of new engines that make it redundant for interplanetary transport.
There is a long way to go on the journey into space though, and starship is the first necessary step.
Why? (Score:2, Interesting)
Yeah, I know - mankind's urge to explore, and simple wanderlust, and because (maybe) we can, etc. And of course, because government dollars flowing to the private sector is advantageous to those hard-lobbying companies. And there are the inevitable scientific and technological advances which we can use here on Earth to make our lives better. But...
I know I keep harping on this, but I do it because it's important. Our planet is burning, in an almost literal sense. We need to be focusing every bit of our know
Re:Why? (Score:5, Insightful)
If your goal is "don't work on researching new technology until you've fully solved all of the problems at home", then I have to ask, how do you enjoy living a hunter-gatherer existence? You're setting a standard to never do basic research, because there will always be problems.
Nobody is saying "dump half of the globe's GDP into space exploration". The world's space agencies spend like one twentieth of a percent of global GDP. And have spawned a massive commercial market in things that benefit life on Earth, which is far larger than what space agencies spend (total space revenue now amounts for about half a percent of global GDP). All of those satellites orbiting Earth aren't up there on a lark, they're doing so because they're profitable to have them up there, because they provide services to the people of the world that people want to pay for. Global communication (particularly in remote areas for ships, planes, and emergency responders, and now increasingly, rural broadband), global positioning and timing, weather monitoring, fire monitoring, other natural disaster monitoring, climate monitoring, scientific research, agricultural management, resource mapping, national security, disaster response, media broadcast, on and on and on.
Basic research is your seed corn; you don't boil and eat it. Basic research is useless until it very suddenly isn't. "OMG, look at all these people wasting all this money trying to make heavier than air machines fly, when we have all these problems to deal with on the ground!" Sure would have been a GREAT idea if we had listened to those people, huh?
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Yeah, I know - mankind's urge to explore, and simple wanderlust, and because (maybe) we can, etc. And of course, because government dollars flowing to the private sector is advantageous to those hard-lobbying companies. And there are the inevitable scientific and technological advances which we can use here on Earth to make our lives better. But...
Name a time - any moment whatever in human history - when because all current problems had been solved, it was morally okay to put any resources, public or private, into exploration?
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We've got MANY technologies due to space programs. They are all extremely useful.
- Solar cells (you know, create electricity from the sun, as opposed to burning something).
- Water filters (kind of useful when you want fresh water).
- Air purifiers (to get those nasty airborne chemicals out of the air).
- Insulation (for clothing, buildings, etc.)
- Improvements to windmills (you know, the electricity generating ones).
There's many more technologies which allow us to be more efficient in one way or the other, he
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You are not wrong. But all these things require understanding of what is to come to justify the effort. Only about 20% of all people are accessible to rational argument. (Incidentally, about 80% of the human race are religious and hence essentially believe in fairy-tales...)
That number is not enough. If we had enough rational people, we would not even be in this mess, as the models were pretty good in the 1980's and all this crap could have been nicely avoided with a determined effort starting at that time.
in 50 years time (Score:2)
That's nice. However... (Score:2)
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There is no known better way. Sometimes a problem is solved. There are countless examples. For example, the commonly used "hammer" is probably a few 1000 years old and there still is no replacement for many of its uses and there probably never will be.
Slowing down? (Score:3)
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Falcon 9s encounter their own exhaust because they're in atmosphere. The exhaust gets slowed down by atmosphere. A rocket fires its exhaust out at some number of km/s. The rocket accelerates in the opposite direction, so not only is it not catching up to its exhaust, it's being pushed in the opposite direction.
There is no "deceleration". It's all acceleration. The universe doesn't care what "direction" you're "moving in." This is called Galilean relativity [wikipedia.org], and we've known about it for 400 years.
Maybe. What why go there? (Score:2)
Even if the human race manages (as it looks now) 2.5C, 3C or 4C of climate change, earth will still be a massive better place for human survival.
Ignoring the Musk fanboys here... (Score:2)
So, this would be like Project Orion, Jr.?
How is this news? (Score:2)
So they are proposing the propulsion system outlined in a 1950s Popular Mechanics magazine? The one that is still not tenable due to not having the material science yet? That's one way to run a scam, I guess.
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To make a trip to Mars in two months, with half the trip spent accelerating and the other half decelerating, the spacecraft would need to maintain an acceleration of approximately 0.0034 g. This level of acceleration is quite gentle and would be barely perceptible compared to Earth's gravity.
# Constants
distance_to_mars_km = 225 * 10**6 # Average distance from Earth to Mars in kil
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Probably good you posted this as AC.
Re:How many G's is that? (Score:4, Informative)
Assuming you still have room to accelerate that's 30 days of n Gs one way, and n G's the other way to decelerate.
How many is n G's?
This is news for nerds... We can do math.
At closest approach, Mars is about 55 million km away (5.5E10m). So turn-around at about 2.75E10m.
One month is roughly 30*24*3600 = 2.6E6s
Assuming constant acceleration: d=0.5at^2 or a=2d/t^2
So unless my maths is very wrong that's a constant acceleration of 0.016/m/s or about 0.0016g. With a maximum speed of about 41.5 km/s
If we could manage a constant 1g acceleration, you could do the trip in about 58 hours.
Re:How many G's is that? (Score:4, Informative)
Addendum: you need to match velocities when you get there.
Eath moves round the sun at about 30km/s while mars is about 24km/s
Worst case, that's going to increase the required acceleration by about 6%.
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And if we could do a sustained 1g for the trip, that is time your body is not decaying in freefall. Can't forget that except for the start of the trip. Earth's naturally supplied 1g field won't be close enough to matter, especially relative to the ship's velocity.
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NASA will ditch them at the smallest glitchs
A good strategy is to fund a hundred ideas, and then ruthlessly cull them at each stage.
DC-X never even made it to MVP.
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Re: Good luck (Score:3)