Manned mission to mars

[karolus10]

I would rather vote for Phobos as better place for outpost, it's much larger and located on lower orbit, so it would be good place for "space station" if this moon could provide any protection from radiation/micrometeorites than regular spacecraft orbiting the planet.

Also it would be interesting if habitation modules used in manned transfer vehicles could be reused for building outpost on Phobos (almost no gravity).

[OtherDalfite]

I would rather vote for Phobos as better place for outpost, it's much larger and located on lower orbit, so it would be good place for "space station" if this moon could provide any protection from radiation/micrometeorites than regular spacecraft orbiting the planet.

Also it would be interesting if habitation modules used in manned transfer vehicles could be reused for building outpost on Phobos (almost no gravity).

If we were to ever try and set up a base near mars, I'd say Phobos would be a pretty solid plan. Not nearly as much effort needed to land on Mars. Barely and fuel needed to come and go. That, and you can just kill a bit of velocity and let Mars' atmosphere take care of slowing you down. If we were to go full dwarf about it and actually mine into Phobos, it could double as a radiation shield.

[NASAFanboy]

I would rather vote for Phobos as better place for outpost, it's much larger and located on lower orbit, so it would be good place for "space station" if this moon could provide any protection from radiation/micrometeorites than regular spacecraft orbiting the planet.

Also it would be interesting if habitation modules used in manned transfer vehicles could be reused for building outpost on Phobos (almost no gravity).

I agree, but he current plan is for a base on Deimnos in 2035. Weird hiw noone covers the mission, despite it being a pretty well-thought out and plausible one.

We need less dV to get to Phobos from LEO than it takes to get to the moon.... Bases on Phobos and robotic rovers are the way to go, to pave way for a manned Mars base.

[quadro7f]

Almost all those questions asked in the first post were discussed on the Startalk radio. I recommend to people, who is interested in that theme - check it out.

It is also very funny

Here is 2 parts of it:

http://www.startalkradio.net/show/packing-for-mars-part-1/

http://www.startalkradio.net/show/packing-for-mars-part-2/

P.S. My favourite moment then they were talking about radiation protection in first part at 31:58, ha ha ha. It just hilarious

Edited May 26, 2013 by quadro7f

[SunJumper]

I would rather vote for Phobos as better place for outpost, it's much larger and located on lower orbit, so it would be good place for "space station" if this moon could provide any protection from radiation/micrometeorites than regular spacecraft orbiting the planet.

Also it would be interesting if habitation modules used in manned transfer vehicles could be reused for building outpost on Phobos (almost no gravity).

I had an idea for a space station in Eve orbit. Kerbals will be situated in Eve-Synchronous orbit, such that they can control rovers on their hemisphere, and very cheaply have excursions to Gilly.

What does this have to do with Mars? If, for whatever reason, we can't haul a Mars lander/re-orbit vehicle to mars, we can at least land on one of the moons, control rovers, and have regular excursions to the other moon.

Edited May 26, 2013 by SunJumper

[ShachonianX]

This is because we just don't have the capability to launch things like that into orbit. The rocket equation is such a harsh mistress that launching anything of moderate size requires a truly titanic rocket. The only concepts we have for viably launching large masses have sat untouched for decades because they're pretty goddamn scary in ways that regular rockets aren't.

Ever heard of orbital assembly? NASA wanted to assemble a spaceship in orbit to be sent to Mars for the Constellation program.

[czokletmuss]

This is the visualisation of the latest NASA's idea (Mars Design Reference Architecture 5.0)

As you can see it was conceptualized beofre the cancellation of the Constelation programe. Pity that we currently don't have any means to provide enough energy for electromagnetic thrusters like VASIMR (note that the Crew Transfer Vehicle in the animation uses three of small electromagnetic engines while the solar panels wouldn't suffice even for one).

And this is how AdAstra (company which is working on VASIMR) sees the potential of their engine:

Edited May 26, 2013 by czokletmuss

[Nibb31]

The plan for the current DSH concept is to use a SEP tug, which would basically be an upscaled version of the standard Boeing 702 ion powered comsats.

http://www.gizmag.com/nasa-solar-propulsion-space-tugboat/21289/

http://www.grc.nasa.gov/WWW/RT/RT2001/6000/6920verhey.html

Edited May 26, 2013 by Nibb31

[EatThePath]

Ever heard of orbital assembly? NASA wanted to assemble a spaceship in orbit to be sent to Mars for the Constellation program.

Of course. But we don't have any orbital construction yards, and most sci-fi ships from games and movies aren't easily built out of modules we can currently launch.

[Rune]

As you can see it was conceptualized beofre the cancellation of the Constelation programe. Pity that we currently don't have any means to provide enough energy for electromagnetic thrusters like VASIMR (note that the Crew Transfer Vehicle in the animation uses three of small electromagnetic engines while the solar panels wouldn't suffice even for one).

Actually, I can see very clearly those are NTR's, because that is what is beselined in DRM 5.0, and what makes sense for a manned Mars missions. Contrary to popular belief, a nuclear-electric concept like VASIMIR takes longer to get to Mars, and exposes the crew to much more radiation, since it spends weeks or months spiraling out of Earth and through the Van Allen belts. That is because system T/W is horribly low. Like ions in KSP are a few orders of magnitude beefier.

And why would you want to do that anyway? It's stupid to carry a reactor, all the equipment to turn thermal energy into electricity, and then use that electricity to run an engine. Why not use the thermal potential of the engine directly? Lighter, simpler, no radiator system. (All those conversions have an efficiency, and the energy that doesn0t go through, you have to get rid off as waste heat.

Rune. Not to mention you need a bigger reactor that for a NTR, actually, in terms of thermal output.

[karolus10]

Idea of space yards is coming from time to time, but let's think about it - this is not like star trek with couple of cargo transporters on huge space station and any kind of industry in space.

You need to launch everything and you can't in any magical way to reduce the mass needed to launch.

With orbital Ship yards you must launch even more by securing components and sending up all construction hardware, workers/engineers (often not suited for flight) food, etc.

Only viable "Ship yard" would be an service platform (it could be refueling station as well) with large truss (2.5m truss sections ?) with dozens of docking ports and few robotic arms (they could be attached to rails on truss) so You could deliver and dock to it multiple modules without own RCS and then use arms to rearrange them into final craft - especially if they will had UI making arms use easier (translation/rotation of the robot tip instead controlling separate joints or possible auto-grabbing arm grapple ports).

EDIT_1:

VASIMR is IMHO an interesting concept, but from engineering point of view this is a just complete rubbish (maybe... if you will had pocket fusion reactor to make it holy grail of engines... but this is not "Iron Man" !), if you put big, heavy, complicated reactor and all hardware needed to operate it you loosing most of the advantage .

Also If people are so concerned about radiation from "tiny" reactors in NERVA engines (comparing to space radiation NTR's aren't so bad), what do you think about having big-ass nuclear reactor sitting next to You ?

EDIT_2:

Also VASIMR engines with all this Hi-tech stuff will not be cheaper... I can assure You.

Edited May 26, 2013 by karolus10

[czokletmuss]

Actually, I can see very clearly those are NTR's, because that is what is beselined in DRM 5.0, and what makes sense for a manned Mars missions. Contrary to popular belief, a nuclear-electric concept like VASIMIR takes longer to get to Mars, and exposes the crew to much more radiation, since it spends weeks or months spiraling out of Earth and through the Van Allen belts. That is because system T/W is horribly low. Like ions in KSP are a few orders of magnitude beefier.

And why would you want to do that anyway? It's stupid to carry a reactor, all the equipment to turn thermal energy into electricity, and then use that electricity to run an engine. Why not use the thermal potential of the engine directly? Lighter, simpler, no radiator system. (All those conversions have an efficiency, and the energy that doesn0t go through, you have to get rid off as waste heat.

Rune. Not to mention you need a bigger reactor that for a NTR, actually, in terms of thermal output.

Derp, you are right of course, these are NTRs not electric ones - my bad.

I agree with the flawed thinking about VASIMR as a magic engine which could take us to Mars in a few weeks - it won't 'cause we don't have enough powerful energy source and the mass of the reactor to power VASIMRs will be huge, thus lowering the TWR. Having said that, do you know anything about current research on NTRs? The advantage of VASIMR is that, well, it will be tested on ISS in the next year or two. Do we even have any NTR at the moment?

On the other hand VASIMR can provide the efficient and cheap way to transport stuff from LEO to Moon orbit:

If you want more than fancy animation go to the AdAstra homepage: http://www.adastrarocket.com/aarc/Technology

Edited May 26, 2013 by czokletmuss

[EatThePath]

Idea of space yards is coming from time to time, but let's think about it - this is not like star trek with couple of cargo transporters on huge space station and any kind of industry in space.

You need to launch everything and you can't in any magical way to reduce the mass needed to launch.

Near term orbital shipyards would indeed probably be orbital assembly and fueling, and maybe patching up problems that arose during launch. From-scratch construction in orbit only starts to make sense when you've got some material sources other than earth.

[Fractal_UK]

Actually, I can see very clearly those are NTR's, because that is what is beselined in DRM 5.0, and what makes sense for a manned Mars missions. Contrary to popular belief, a nuclear-electric concept like VASIMIR takes longer to get to Mars, and exposes the crew to much more radiation, since it spends weeks or months spiraling out of Earth and through the Van Allen belts. That is because system T/W is horribly low. Like ions in KSP are a few orders of magnitude beefier.

And why would you want to do that anyway? It's stupid to carry a reactor, all the equipment to turn thermal energy into electricity, and then use that electricity to run an engine. Why not use the thermal potential of the engine directly? Lighter, simpler, no radiator system. (All those conversions have an efficiency, and the energy that doesn0t go through, you have to get rid off as waste heat.

Rune. Not to mention you need a bigger reactor that for a NTR, actually, in terms of thermal output.

For Mars, VASIMR is probably unnecessary but the reason you might want to use it (or a magnetoplasdynamic rocket, which has about the best thrust/KW of the electric propulsion systems) is the excellent specific impulse. A conventional NTR is not going to compete on efficiency though a liquid or gas core version might.

Incidentally, you would still need radiators on an NTR type rocket because the exhaust will only be so efficient at dissipating heat and the fission reaction is occurring inside the ship. The only way of limiting (still not avoiding entirely) this is to use something like a nuclear salt water rocket where the majority of the fission reaction is occuring within the rocket nozzle outside of your ship. The principle of the design seems sound but its still very much an unproven concept at this time.

The exhaust velocity of the nuclear rocket and hence its specific impulse are heavily dependent upon the core temperature of that rocket which means that high efficiency designs pose both a question in materials science as well as adding to the required radiator capacity. A nuclear electric rocket, on the other hand is less reliant upon a ludicrous core temperature to operate efficiently and many of the electric propulsion systems are pretty efficient in and of themselves.

[czokletmuss]

For Mars, VASIMR is probably unnecessary but the reason you might want to use it (or a magnetoplasdynamic rocket, which has about the best thrust/KW of the electric propulsion systems) is the excellent specific impulse. A conventional NTR is not going to compete on efficiency though a liquid or gas core version might.

I don't know what is the ISP for NTR but 5000s is pretty impressive.

[Fractal_UK]

I don't know what is the ISP for NTR but 5000s is pretty impressive.

You should look up HiPeP, they achieved over 8000s during the testing of that, very impressive indeed.

Solid core NTR has about 930s. Liquid and closed cycle gas core designs are expected to be in the 1500-2000s range while open cycle gas core might achieve as high as 5000, with the downside of spewing highly radioactive exhaust out of the back and making retaining your nuclear fuel difficult.

[jgkamat]

you guys should check this out. Fuel=less if you go to a moon.

http://www.caltech.edu/content/caltech-space-challenge-mission-martian-moon

It also talks about some of the problems you were discussing earlier

[Rune]

Oh, electric engines do have use as cargo tugs and unmanned probes. I'm all for developing engines and solar panels (more like sails) in the range of 100kws for cargo. But that does little for a manned mars mission other than adding a huge development cost. Use it when you go grabbing asteroids and fuel and stuff.

As to nuclear engines, specifically of the Nerva type, two flight-capable models have been built for ground-testing as of today, one in the US and one in Russia (though I don't know if the russian was actually ever fired). At 850-875s isp when running LH2 (Nerva was tested on a lot of stuff including methane and water), regenerative cooling was sufficient (nuclear engines run cooler than normal rocket engines, after all). I can imagine that actually adding all the nice ideas that have been suggested since then (new materials for the fuel, mainly) would take some development and time, probably in the billion dollar range like a big first stage engine, but I can't believe it would be too difficult to do so if the will was really there.

Dedicated radiators I have only seen for additional electrical generator groups running stirling engines or bryton turbines off the reactor's excess heat, at least for solid core NTRs. Other nuclear engines can of course achieve more energy density and get higher isp, but as you point out beyond about 1000s we run into present-day material limits for the reactor that make solid-core NTR's unpractical.

But that's what other nuclear concepts are for

Rune. From 1,000s to 1,500,000s, there's a plausible nuclear engine to suit every need.

[Tangent]

Look at page 17 http://www.csc.caltech.edu/stuff/VoyagerFinalReport.pdf

Its team voyagers entry to the Caltech space challenge.

Its uses an image from ksp

Edited May 26, 2013 by Tangent

[tanawsomeguy55]

Politicians are the worst asses anyway, quite straightforward.

About the technological assessment: large spaceships as those seen in games or movies aren't researched into, which is really stupid if I'm honest with you. Today's manned space travel research goes primarily into tiny confined capsules.

It would be much, much better to invest money into massive shipyards which directly blast huge steel constructs into orbit, where they are primarily fueled and head off for the Asteroid Belt (to begin construction of a real space-shipyard which uses the locally available metals both for itself and for the ships it will once commission).

Instead we sit on our very own Earth, constructing oversized ICBMs as means of getting into space, and fighting against each other rather than being a progressive species which aims for the stars. Its shuttering to look at humanity: bureaucracy rules over our resources only to greedily take them (the money) for themselves.

i belive you completly if needed we could turn the ISS into to a ship yard or make a enterprise like in star trek but with toned down technology

[Nibb31]

Who needs a shipyard? The Russians didn't need a shipyard to build Mir, neither did the ISS need to be built in a shipyard.

Sending up highly qualified astronauts to do construction work is wasteful and extremely expensive. EVA activities usually require months of training, defining procedures, logistics, and are also quite tedious and dangerous. The best way to build a large ship in space to send up modules on a tug and do as much automated docking and assembly as possible.

[Sof]

Sending up highly qualified astronauts to do construction work is wasteful and extremely expensive. EVA activities usually require months of training, defining procedures, logistics, and are also quite tedious and dangerous. The best way to build a large ship in space to send up modules on a tug and do as much automated docking and assembly as possible.

Wasteful and expensive as they may be, they will undoubtedly by necessary since humans are not yet rivaled in dexterity by machines. Whilst the bulk of construction for a Mars rocket could be modulised and assembled by docking, some astronauts will be required for the fine touches.

[Nibb31]

Sure, but that gives them something to do on their 8 month trip. The actual assembly should be as automated as possible.

One of the major teachings of the Shuttle/ISS program is that that is not how you should build stuff in space.

[Rune]

Very true, Nibb31, you are absolutely right. EVA work is dangerous and expensive. And likely to be carried out by robots in the near future (that's what robonaut is for, right?).

A place to assemble stuff and refuel might be nice. But that would be a big ass fuel depot with minimal stationkeeping capabilities and perhaps a pressurized crew module and a logistics one. Think simplified ISS, or MIR. Hardly the traditional sci-fi view of an orbital shipyard. And assembly is big cylinders docking and berthing to each other, some visual inspections of the connections with robots, and pumps moving fluids around (which is a greater challenge than you might think). And it certainly wouldn't be on the ISS orbit, that's way too inclined for interplanetary travel.

As to going to Phobos (or Deimos), those could be a nice source of materials with swallow gravity wells, but I wouldn't put a base on the surface. Two reasons: artificial gravity becomes difficult or impossible, and dust. And probably dust is the bigger issue, in a low gravity environment, it will be everywhere, and it will be razor-sharp like in the moon due to lack of weather. A guaranteed maintenance nightmare. Nonono, the only thing that goes down to the moons are science packages and mining equipment. Base camp remains on orbit, safely spinning and doing its thing. (Fuel depot? Hab? Laboratory? Industry?... Even colony?).

Rune. Just like in KSP, actually. Minus the dust, but still you don't crash in orbit.

Edited May 27, 2013 by Rune

[karolus10]

Robonaut II and other humanoid robots can (IRL) be good extension of robotic arms, because astronaut can sit safe on station and operate in space with better dexterity (like bare hands) and possibly with better touch sensation than using bulky gloves.

Other crew members can jump-in to action instantly, without long suiting-up and oxygen pre-breathing process (no full pressure suit) to go do anything outside... even if he will not replace astronaut it can be the only way to save the ship/station from emergency, if you had only minutes to solve the problem or evacuate (or die ,if crew had no means of escape).

Robots using telepresence, can allow do jobs that are beyond capabilities or too dangerous like working around zones with high radiation (servicing at close unshielded reactors, NTR engines) exposure risk.

Also this interface can be very useful to operate other vehicles in easy and natural way - we can send the rover into region of interest (out of astronaut range or not worth the effort to make the trip ourselves) and investigate the site up close & personal (live link).

Edited May 27, 2013 by karolus10