SSTO to mars and back again.

Seer · 2007-09-19 13:26:41

How about using a fueling a base first, vtvl ssto in leo and sending it to mars.

The ship would use hydrogen and oxygen to get to mars; once on mars it would make methane and oxygen from hydrogen feedstock to fuel itself for the ride back to leo. To take off from Mars, the ship would need methane engines, carried in addition to the hydrogen ones. Methane would be stored in the hydrogen tank, and the trip back would run fuel rich. I'd imagine that the heatshield for this ship would be cooled by excess hydrogen or water, via transpiration.

The ship would mass about 250 tonnes in leo, and around 50 tonnes on the surface of Mars. The hydrogen feedstock would mass about 12 tonnes, leaving 38 tonnes for the ship, the nuclear reactor, isru equipment, crew of four and their consumeables, plus scientific payload. The stay on Mars would last around 18 months.

The actual size of the craft would be quite large: about 20 metres tall, plus the length of the landing legs. Its diameter would be roughly 10 metres, allowing a roomy crew cabin. Getting things down from the ship's cabin and hold to the surface would be inconvenient, and need some sort of winch or lift.

I know most people here on these forums aren't big fans of ssto, and I have a lot of sympathy with them. So what are my motivations for using a ssto to go to mars? They are chiefly because I fear the current plan to return to the moon and then go to mars is too slow, expensive and boring to succeed. The main problem is the need to develop a heavy lift launch vehicle, and then to maintain the production and launch facilities indefinitely

cIclops · 2007-09-19 13:51:59

On orbit refueling will work once there is a really cheap way to launch and and store fuel there. SSTO would also be a nice technology to have as it should reduce the cost to reach LEO. Producing fuel on Mars would be necessary too unless SSTO becomes really really cheap. These three technologies would enable a bigger, better, cheaper Mars mission, but they don't exist right now and probably won't for a long time.

What we will have is Ares V, it can put about 130 mT into LEO - far cheaper than any other vehicle today. What we still need is a crew transfer ship and a landing/ascent vehicle to reach the surface of Mars and the facility to refuel it there.

The plan to return to the Moon can be done a lot faster if enough people support it. Currently the next lunar landing is planned for 2019, but this could be much earlier if Congress fully fund the program. Getting back to the Moon is an important next step, then NEO missions and then Mars. A lot of new technology as well as the Mars vehicles has to be developed, but this can all be done in parallel. Mars missions could begin in the early 2020s.

Tom Kalbfus · 2007-09-22 08:16:40

The plan to return to the Moon can be done a lot faster if enough people support it. Currently the next lunar landing is planned for 2019, but this could be much earlier if Congress fully fund the program. Getting back to the Moon is an important next step, then NEO missions and then Mars. A lot of new technology as well as the Mars vehicles has to be developed, but this can all be done in parallel. Mars missions could begin in the early 2020s.

And what state of the art technologies will we have precisely in 2019? I need to make some investments, and if I know exactly what the hot technologies are in 2019, I can make a killing!

How about this, lets dispense with the Ares V altogether and plan for the existance of a space elevator by 2019, all we really need is for certain breakthroughs in mass production of carbon nanotubes by 2012 and then we can have a space elevator ready to hoist the components of our mission to return to the Moon into orbit.

cIclops · 2007-09-22 09:23:58

And what state of the art technologies will we have precisely in 2019? I need to make some investments, and if I know exactly what the hot technologies are in 2019, I can make a killing!

It's unlikely that this type of technology (ISRU etc etc) will be profitable in 2019, so hold off on those investments for another decade or more!

Tom Kalbfus · 2007-09-22 11:12:58

And what state of the art technologies will we have precisely in 2019? I need to make some investments, and if I know exactly what the hot technologies are in 2019, I can make a killing!
It's unlikely that this type of technology (ISRU etc etc) will be profitable in 2019, so hold off on those investments for another decade or more!

Its hard to plan a mission 12 years in the future.

"You take the ???? and you put it together with the ????... etc."

So what sort of displays will the CEVs have in 2019, will they use holographic technology? Will the ship's computer use AI software? What about nanotechnology, or micromachines? Advanced robotics? Ion propulsion, plasma drives, fission rockets? If we are to plan a mission using 2019 technology right now, which ones shall we pick? Will we have to decise upon which technologies will be available to us in that time or will we use 2007 technologies and no matter what happens still use those technologies, obsolete computers and everything?

cIclops · 2007-09-22 11:36:02

So what sort of displays will the CEVs have in 2019, will they use holographic technology? Will the ship's computer use AI software? What about nanotechnology, or micromachines? Advanced robotics? Ion propulsion, plasma drives, fission rockets? If we are to plan a mission using 2019 technology right now, which ones shall we pick? Will we have to decise upon which technologies will be available to us in that time or will we use 2007 technologies and no matter what happens still use those technologies, obsolete computers and everything?

Orion is being designed right now with current technology. Sure it could require technology that doesn't exist, but NASA has already gone down this high risk path before and it leads to budget and schedule overruns and even failure. Good examples are Venture Star and the Shuttle itself. When a long complex project like Orion is started, trades have to be made between TRL, risk, cost and schedule. Good engineers always seek to reduce risk in order to meet requirements, budget and schedule. Reducing risk means using technologies that are ready.

NASA has an advanced capabilities program that funds new technologies including:

Structures, Materials, and Mechanisms; Protection Systems; Non-Toxic Propulsion; Energy Storage; Thermal Control; Avionics and Software; Environmental Control & Life Support; Crew Support and Accommodation; In-Situ Resource Utilization; Robotics, Operations and Supportability; and Fission Surface Power Systems. (FY2008 Budget request ESMD-64)

It's hoped that when methane engines are available they will be used by the Orion service module, another possibility is to use composite materials instead of Al-Li for the capsule.

Tom Kalbfus · 2007-09-22 12:29:01

But isn't there a risk that the astronauts climbing into the Orion capsule for the first time in 2019 are going to feel they've stepped into a Museum?

With computer technology dated back to 2008, and the displays being only 2 dimensional and not even HD 2d at that? The engineer appologizes and says that the design was frozen way back in 2008, and that it took 11 years to put the thing together and test it thoroughly, of course he had no help and had to do it all by himself in his garage as Congress wouldn't appropriate the necessary money for him to have assistants.

cIclops · 2007-09-22 12:46:36

But isn't there a risk that the astronauts climbing into the Orion capsule for the first time in 2019 are going to feel they've stepped into a Museum?
With computer technology dated back to 2008, and the displays being only 2 dimensional and not even HD 2d at that? The engineer appologizes and says that the design was frozen way back in 2008, and that it took 11 years to put the thing together and test it thoroughly, of course he had no help and had to do it all by himself in his garage as Congress wouldn't appropriate the necessary money for him to have assistants.

With full funding astronauts will be launched inside Orion in 2013, right now it will be 2015. Engineering decisions have to be based on the technologies that are ready unless they want to risk delay and overruns (see JWST) Avionics can be upgraded (at enormous cost) and this was done in the Shuttle, many things can be improved with enough time and money - a good design allows for better technologies to be incorporated later - HST proved this.

Call Congress now and tell them to fully fund NASA, we don't want astronauts to feel like their flying retro spacecraft!

Tom Kalbfus · 2007-09-23 08:07:46

But isn't there a risk that the astronauts climbing into the Orion capsule for the first time in 2019 are going to feel they've stepped into a Museum?
With computer technology dated back to 2008, and the displays being only 2 dimensional and not even HD 2d at that? The engineer appologizes and says that the design was frozen way back in 2008, and that it took 11 years to put the thing together and test it thoroughly, of course he had no help and had to do it all by himself in his garage as Congress wouldn't appropriate the necessary money for him to have assistants.

With full funding astronauts will be launched inside Orion in 2013, right now it will be 2015. Engineering decisions have to be based on the technologies that are ready unless they want to risk delay and overruns (see JWST) Avionics can be upgraded (at enormous cost) and this was done in the Shuttle, many things can be improved with enough time and money - a good design allows for better technologies to be incorporated later - HST proved this.
Call Congress now and tell them to fully fund NASA, we don't want astronauts to feel like their flying retro spacecraft!

It would frankly be embarrasing if NASA takes too long getting back to the Moon, there is the Apollo standard they are being measured against. If NASA takes significantly longer to get back to the Moon than the Apollo program did starting with Kennedy's speech, then I wonder what excusing NASA will find, seeing how all the technology is already established. The only one they could have is lack of money, but we were not richer in the 1960s. All the pioneering work has already been done in the Apollo program, the first step in the Constellation program is simply to replicate those results. If anything the Chinese will hopefully give us a boost, otherwise NASA will appear to cede the Moon to the Chinese. Once the ISS is built it shouldn't cost that much, since all we are really talking about is ferrying humans and equipment to and from it in space capsules. Werner Von Braun was much in favor of a space station as he felt that it would be incentive for us to keep visiting it or abandon the hardware. In order to get our money's worth out of the ISS, we'll have to keep visiting it, and building space capsules, that will keep our manned space program alive if nothing else would - at least until it wears out. I view the ISS as a sort of floor. Now since we will have the Orion space capsule, we might want to consider returning to the Moon as it has been almost 50 years, if for no other reason than to preclude national embarrasment by being beated by the Chinese. I think the name of the program Constellation is very appropriate, as a constellation is a myriad points of light, this implies that the Constellation program doesn't just have one destination in mind, but several. I think the destinations are the Moon, Mars and the Asteroids. Having a continuing Moon program will help reduce the per unit cost of each Mars mission as they will use hardware in common, and the asteroids are icing on the cake, not to mention the launching of space telescopes.

cIclops · 2007-09-23 11:39:41

RTTM is not Apollo. It will be done with far greater capability for a fraction of the cost. With full funding the seventh landing could be done around 2015. Even with 2007 technology, the need for a safe, reliable and affordable transportation program makes development longer than Apollo's crash national program. Apollo wasn't safe, reliable or affordable. Once complete Constellation will provide the basic elements for exploration beyond the moon.

Griffin has already said he believes that China could be on the Moon before NASA returns. This might be the catalyst that will cause Congress to react.

Yes ISS should be affordable too as well as RTTM, building an Outpost, visiting NEOs and missions to Mars. Furthermore an expanding science program is also affordable.

Given public support, this can all become real.

Tom Kalbfus · 2007-09-26 08:54:18

RTTM is not Apollo. It will be done with far greater capability for a fraction of the cost. With full funding the seventh landing could be done around 2015. Even with 2007 technology, the need for a safe, reliable and affordable transportation program makes development longer than Apollo's crash national program. Apollo wasn't safe, reliable or affordable. Once complete Constellation will provide the basic elements for exploration beyond the moon.

Seems to me that we afforded Apollo from 1967 to 1972 quite nicely, and we did all this while fighting a war in South-East Asia. Compared to Vietnam, Apollo was an afterthought, yet the war continued for 3 years after Apollo was shut down, and Apollo wasn't restarted after the war ended.

Safe? Well Apollo's safety record was better than the US Space Shuttle, we lost only three astronauts on the ground compared to the entire crews of both Shuttles Challenger and Columbia. Apollo 13 proved the inherent safety of the mission design, when the lander was used as a life raft. If 90% of the extra delay and cost is safety, then I think we ought to reexamine what were doing, we certainly don't use the same standards of safety for fighting the Iraq War, nor should we, because we'd lose if we'd try for the perfect battle plan with 0% casualities. I think a manned mission to the Moon and Mars is best handled like a military operation, we must plan for an acceptable level of casualities. When police officers walk the beat, we accept the notion that some of those officers will die in the line of duty. If we raise our standards too high, we fail.

Griffin has already said he believes that China could be on the Moon before NASA returns. This might be the catalyst that will cause Congress to react.
Yes ISS should be affordable too as well as RTTM, building an Outpost, visiting NEOs and missions to Mars. Furthermore an expanding science program is also affordable.
Given public support, this can all become real.

Antius · 2007-09-26 09:06:34

One way of getting around the on orbit refuelling problem is to use a hydrogen fuelled solid-core nuclear thermal engine within the SSTO. This could reach Mars without the need for on-orbit refuelling, by virtua of its very high specific impulse. I have even seen discussion of air-augmented nuclear fission rockets, which burn the heated hydrogen with ram-jet compressed air in a second combustion chamber. The effective ISP is well over 1000 seconds.

A nuclear SSTO/SSTM would be relatively compact, but residual radiation from the core may be a significant additional dose burden to the crew during long trips. Maybe some means of ejecting the spent core could be engineered into the rocket?

Tom Kalbfus · 2007-09-26 10:31:29

One way of getting around the on orbit refuelling problem is to use a hydrogen fuelled solid-core nuclear thermal engine within the SSTO. This could reach Mars without the need for on-orbit refuelling, by virtua of its very high specific impulse. I have even seen discussion of air-augmented nuclear fission rockets, which burn the heated hydrogen with ram-jet compressed air in a second combustion chamber. The effective ISP is well over 1000 seconds.
A nuclear SSTO/SSTM would be relatively compact, but residual radiation from the core may be a significant additional dose burden to the crew during long trips. Maybe some means of ejecting the spent core could be engineered into the rocket?

But why drag the SSTO all the way to Mars?
A scramjet would not work on Mars.
Any winged SSTO designed to lift off from Earth would have the wrong proportions for a runway landing on Mars even assuming there was a runway on Mars, and if there was the landing speed would have to be too high to maintain lift on Mars, and if one installed "Martian" wings on the SSTO they would be too massive and cumbersome to lift-off from Earth.

Only one kind of SSTO would work, that would be a tail launch/tail landing system. The SSTO also could not be air breathing, since the air on MArs contains no oxygen. If you forgo Scramjets for SSTO, you must carry the oxydizer which adds weight and makes SSTO harder.

cIclops · 2007-09-27 08:22:33

Apologies ... last post was accidentally deleted.

Antius · 2007-09-28 09:37:34

One way of getting around the on orbit refuelling problem is to use a hydrogen fuelled solid-core nuclear thermal engine within the SSTO. This could reach Mars without the need for on-orbit refuelling, by virtua of its very high specific impulse. I have even seen discussion of air-augmented nuclear fission rockets, which burn the heated hydrogen with ram-jet compressed air in a second combustion chamber. The effective ISP is well over 1000 seconds.
A nuclear SSTO/SSTM would be relatively compact, but residual radiation from the core may be a significant additional dose burden to the crew during long trips. Maybe some means of ejecting the spent core could be engineered into the rocket?
But why drag the SSTO all the way to Mars?
A scramjet would not work on Mars.
Any winged SSTO designed to lift off from Earth would have the wrong proportions for a runway landing on Mars even assuming there was a runway on Mars, and if there was the landing speed would have to be too high to maintain lift on Mars, and if one installed "Martian" wings on the SSTO they would be too massive and cumbersome to lift-off from Earth.
Only one kind of SSTO would work, that would be a tail launch/tail landing system. The SSTO also could not be air breathing, since the air on MArs contains no oxygen. If you forgo Scramjets for SSTO, you must carry the oxydizer which adds weight and makes SSTO harder.

No reason, other than to simplify the overall complexity of getting to Mars, and therefore reduce overall costs. A nuclear SSTO has the potential to function as a Single-Stage-to-Mars vehicle. For lunar missions it might even be possible to fly there and back on a single tank of H2. This would allow trans-Mars vehicles to function much as airliners do here on Earth. The only parts of the vehicle that would be disposable, would be the hydrogen fuel, the nuclear core (which would be relatively compact and could be replaced each mission) and the Earth return heat shield.

Also it is worth pointing out, that a nuclear hydrogen air-augmented system would work on Mars (H2 + CO2 = CO + H2O).

An air-assisted nuclear engine would have a significantly higher ISP when operating in booster mode in Earth's atmosphere, but also higher dead-weight during trans-Mars injection. The benefits of the airbreathing system are maximised if the vehicle is used in direct throw, given that a larger portion of the acceleration takes place within Earth's atmosphere.

Terraformer · 2007-10-06 11:47:46

You want to use valuable Duetranium (H2)??

samy · 2007-10-06 13:46:23

Deuterium is "D", "H2" is two Hydrogen-1 atoms together as one molecule.

publiusr · 2007-11-09 14:26:19

Ares V or bust.

Seer · 2008-03-24 17:37:57

bump thread.

Any more commentary?

louis · 2008-03-27 02:51:35

Seer -

Yes, I like the basic idea and favour it myself (in a perfect world!).

I agree with most of your thoughts.

Are you incorporating retro-rockets in your proposal? I favour that. Assuming the stability issue can be resolved then I think that is the safest and surest way down - only one mechanism to fail , not three as with some Mars landers.

I wonder also whether we need to be dependent on fuel production on the surface. Not that I am against fuel production on Mars in the longer run, but I against creating a potential failure point if it can be avoided for the first mission.

I am currently thinking in terms of two robot pre-missions (essentially supplies) and two human missions. If we are thinking in terms of continuous settlement, can we not have a situation where further landers come in a couple of years' time and include fuel supplies for the initial colonists to make the return journey? Or perhaps that could be the back up plan - so if fuel production has been successful, the imported fuel would simply go into the energy storage systems as a bonus.

I don't know how much technical knowledge you have Seer - I don't claim too much. The difficulty I think is to see what kind of problem we are faced with regarding a Mars landing. Is it a kind of D Day problem - is there really only one basic solution (the landing have got to be on the Channel coast and Normandy is preferable to Brittany or Calais)? Or is it a problem with several possible solutions? Are we in a position as at the start of jet travel, where engineers could have gone with a delta wing solution (which some people think would still be preferable to the "tube with wings" concept)? Or could we have switched to jump jet technology at some point, so as to avoid all the problems of approach and noise arond airports?

I just have a sneaky suspicion that a single stage solution has not been given top billing because a lot of R&D has already gone into multi stage rocketry. But perhaps it is what the ride to Mars calls for.

Calliban · 2024-05-24 21:12:09

I'm not sure if this is the right place to put this. The current concept for the pulsed plasma drive produces 100KN of thrust with 5000s of ISP.
https://www.sciencedirect.com/science/a … 6522001187

If we can increase the thrust to weight ratio, then a pulsed plasma drive ship could take off from Earth, fly all the way to Mars and land, all as a single stage without refuelling in orbit. The 50km/s exhaust velocity allows that.

The catch is that like Project Orion, the plasma drive has a radioactive exhaust. The PPD is far more efficient at exploiting nuclear energy to produce thrust than Orion would have been. So there will be less radioactivity per tonne delivered to space. But a radioactive exhaust is unavoidable. So using this thing in the future requires than people stop going loony at the prospect of radioactivity release. I don't know if we will ever get to point where people think rationally about that. But if we do, it opens the prospect for airline like travel to other planets. We could get to the moon in hours. To Mars in weeks, instead of months. Manned missions to the outer planets become feasible as well.

It takes 62.7MJ of energy per kg, to reach Earth escape velocity. So a 1000t spacecraft will need 62.7TJ. A single fission is 3E-11 joules. So a 1000t ship will need 2.09E24 fission events to reach Earth escape. That is 3.47 mols of 235U, or complete fission of 0.816kg of uranium. That is the equivelent of detonating a 15kT nuclear warhead - about the same as the Hiroshima bomb.

Between the 1940s and 1960s, a total of 217MT of pure fission bombs were used in atmospheric testing. So a single launch of 1000t pulsed plasma propelled ship would release 0.0069% of the total atmospheric yield of nuclear testing. However, for regular launches the effects would add up. Say the world launches 3 aday, making for a total of 1000 per year. The total atmospheric contamination in 1 year would be 6.9% of the total contamination from atmospheric fission bomb testing. So after a decade of launches, the radioactive effects would be comparable to those resulting from atmospheric weapons testing. I cannot see people tolerating that.

There are ways of reducing the scale of the problem. One way is to using a chemical booster lower stage to push the ship out of Earth's atmosphere before the atomic drive lights up.

Last edited by Calliban (2024-05-24 21:50:40)

Mars_B4_Moon · 2024-05-25 10:19:31

Spaceplanes: why we need them, why they have failed, and how they can succeed

https://thespacereview.com/article/4791/1

SpaceNut · 2024-05-25 10:33:58

Pulsed plasma rocket (PPR): Shielded, fast transits for humans to Mars

The future of a space-faring civilization will depend on the ability to move both cargo and humans efficiently and rapidly. Due to the extremely large distances that are involved in space travel, the spacecraft must reach high velocities for reasonable mission transit times. Thus, a propulsion system that produces a high thrust with a high specific impulse is essential. However, no such technologies are currently available.
Howe Industries is currently developing a propulsion system that may generate up to 100,000 N of thrust with a specific impulse (Isp) of 5,000 seconds. The Pulsed Plasma Rocket (PPR) is originally derived from the Pulsed Fission Fusion concept, but is smaller, simpler, and more affordable.
The exceptional performance of the PPR, combining high Isp and high thrust, holds the potential to revolutionize space exploration. The system's high efficiency allows for manned missions to Mars to be completed within a mere two months.
Alternatively, the PPR enables the transport of much heavier spacecraft that are equipped with shielding against Galactic Cosmic Rays, thereby reducing crew exposure to negligible levels. The system can also be used for other far range missions, such as those to the Asteroid Belt or even to the 550 AU location, where the sun's gravitational lens focuses can be considered. The PPR enables a whole new era in space exploration.
The NIAC Phase I study focused on a large, heavily shielded ship to transport humans and cargo to Mars for the development of a Martian base. The main topics included: assessing the neutronics of the system, designing the spacecraft, power system, and necessary subsystems, analyzing the magnetic nozzle capabilities, and determining trajectories and benefits of the PPR. Phase II will build upon these assessments and further the PPR concept.
In Phase II, we plan to:
Optimize the engine design for reduced mass and higher Isp
Perform proof-of-concept experiments of major components
Complete a ship design for shielded human missions to Mars

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#1 2007-09-19 13:26:41

Re: SSTO to mars and back again.

#2 2007-09-19 13:51:59

Re: SSTO to mars and back again.

#3 2007-09-22 08:16:40

Re: SSTO to mars and back again.

#4 2007-09-22 09:23:58

Re: SSTO to mars and back again.

#5 2007-09-22 11:12:58

Re: SSTO to mars and back again.

#6 2007-09-22 11:36:02

Re: SSTO to mars and back again.

#7 2007-09-22 12:29:01

Re: SSTO to mars and back again.

#8 2007-09-22 12:46:36

Re: SSTO to mars and back again.

#9 2007-09-23 08:07:46

Re: SSTO to mars and back again.

#10 2007-09-23 11:39:41

Re: SSTO to mars and back again.

#11 2007-09-26 08:54:18

Re: SSTO to mars and back again.

#12 2007-09-26 09:06:34

Re: SSTO to mars and back again.

#13 2007-09-26 10:31:29

Re: SSTO to mars and back again.

#14 2007-09-27 08:22:33

Re: SSTO to mars and back again.

#15 2007-09-28 09:37:34

Re: SSTO to mars and back again.

#16 2007-10-06 11:47:46

Re: SSTO to mars and back again.

#17 2007-10-06 13:46:23

Re: SSTO to mars and back again.

#18 2007-11-09 14:26:19

Re: SSTO to mars and back again.

#19 2008-03-24 17:37:57

Re: SSTO to mars and back again.

#20 2008-03-27 02:51:35

Re: SSTO to mars and back again.

#21 2024-05-24 21:12:09

Re: SSTO to mars and back again.

#22 2024-05-25 10:19:31

Re: SSTO to mars and back again.

#23 2024-05-25 10:33:58

Re: SSTO to mars and back again.

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