A different look at the trip to Mars

[ZiraldoAerospace]

I have had this idea for a long time, so I will just throw it out there. Keep in mind, I haven't thought it out a ton so don't be too hard on me Anyway, I think, once we are ready to go to Mars, instead of building a purpose built ship to go there, why don't we build a space station using, say, Bigelow Aerospace's BA-330's and some sort of propulsion hub and some solar panels? If there were enough panels, you could even put a VASMIR ion engine on it, which would speed it up considerably. Anyway, is this just crazy talk or is it a good idea?

 

[a_lost_packet_]

I have had this idea for a long time, so I will just throw it out there. Keep in mind, I haven't thought it out a ton so don't be too hard on me Anyway, I think, once we are ready to go to Mars, instead of building a purpose built ship to go there, why don't we build a space station using, say, Bigelow Aerospace's BA-330's and some sort of propulsion hub and some solar panels? If there were enough panels, you could even put a VASMIR ion engine on it, which would speed it up considerably. Anyway, is this just crazy talk or is it a good idea?

Well, in reality, what's the difference between a "space station" and a "space ship?" One moves independent of an orbit (most of the time) and one doesn't (most of the time.) That's about it with the exception of how it is supplied.

A human Mars mission would likely be assembled from components in space that were placed over multiple launches. So, in that respect, it would sort of be like a space-station.. that had some big engines strapped on it.

 

[dangineer]

I like your thinking. You're idea represents a very modular design with a very open architecture. However, here are some technical challenges that your idea may encounter:

*There are still several expensive technologies that need to be developed or implemented to be able to complete the trip including
-a landing vehicle/habitat for the surface of Mars
-a shielding system to protect the astronauts from the radiation en route and on the surface

*Extra weight means extra power and extra propellant which means more extra weight, so weight needs to be minimized

*If you build something that can also serve other purposes (on orbit science, for instance), that generally means extra weight.

*Your idea could be done if constructed over a long period of time, thus reducing the immediate costs. However the overall cost will be much larger, which would be a hard sales pitch for congress, if built by NASA.

Generally, purpose built designs are the cheapest, but open architecture designs are the most flexible. Maybe your idea could be implemented after the key technologies are more developed and regular trips to Mars demand more flexibility.

 

[Beanze]

I'm with you there!
How are we doing on these Hibernation pods? ^^,

 

[orionrider]

you could even put a VASMIR ion engine on it, which would speed it up considerably

At this point, the VASIMR 200KW engine at full throttle pushes about as much as a medium burger with fries on your table.
5 Newton is not much to go to mars. Even working almost constantly it is not enough to totally counter the ISS orbital decay. Ah, and the available power from the ISS is less than 200 kW, despite the huge solar panels...

VASIMR is a great innovation, but not for that kind of mission. :idea:
http://en.wikipedia.org/wiki/Variable_S ... sma_Rocket

What you need is a rocket large enough to launch several 200ton propellant tanks for your spacecraft.
Something like that:

http://www.k26.com/buran/Info/Hercules/vulkan.html
http://en.wikipedia.org/wiki/Energia

 

[TopNob]

Have they worked out a way to actually land heavy payloads on mars? Otherwise its all for northing....

http://www.universetoday.com/2007/07/17 ... ed-planet/

 

[kelvinzero]

I think the space station would have to be designed with this in mind. I quite like the idea that the ISS could have modules that can be undocked, connected with others (especially an orion capsule) and sent on longer missions.

I have heard it claimed that the ISS was designed to require the shuttle for assembly. A great crime if that is true, and prevented these modular ideas being explored.

People often say they hate the shuttle era because we just went round and round in orbit. But as this thread observes, the ability to just survive in space long term is half the problem solved to getting anywhere in the solar system. Actually landing on mars requires a whole new hardware, but in many ways Phobos interests me more than mars, for example.

Unfortunately I don't think we really made all that much progress in just surviving in space over this period. Does anyone know what the budget on life support research was compared to shuttle launches? I imagine it was way smaller.

 

[SteveCNC]

I like the tethered landing on Olympus Mons idea , we could create a landing center and set up the initial ship as an orbiting station/drop point . The only thing I'm not sure of is if there is still any siesmic activity or not . Might be a good thing to check out on the next probe , send some spikes to relay seismic data . Would suck to land there and find out it's still rumbling .

 

[kelvinzero]

What you need is a rocket large enough to launch several 200ton propellant tanks for your spacecraft.
Something like that:

http://www.k26.com/buran/Info/Hercules/vulkan.html
http://en.wikipedia.org/wiki/Energia

Im guessing you mean 200ton full, so only say twenty tons dry if you use fuel depots? Existing launchers can do 30 tons already I think.

I like the modular possibilities of this idea. For launching something big, how about finding a way to strap multiple second stages together with minimal assembly. Or perhaps you could use boosters to get an entire first stage to orbit. Another worthwhile ability would be to be able to transfer propellent between stages if one of the engines does not work. This is similar to what is required for fuel depots so it could be part of the same research perhaps.

 

[cavesofmars]

You may want to check out my proposal for the International Moon Transit Station (IMTS) and its modular approach to the assembly of an artificial gravity environment. I have suggested that the attachment of a propulsion system to the station would allow it to serve as a space liner. My guess is that some kind of nuclear propulsion will be required to move this large a mass up to the needed speed. The materials from the moon will supply hydrogen, oxygen, and anything else required for the journey. By designing a supporting system of ferries, the space liner would never have to stop on its journey but would continually orbit the Earth and Mars.

 

[EarthlingX]

This is hidden in List of Multiple Threads on the Same Topic on top of this forum :
VASIMR based spaceship for heliosphere

What we need is Galactica Lite; a hab, small reactor, VASIMR or MPD power, lander/return vehicle etc. and a gas generating hab launched to the surface long before the people. Get there in 3-4 months and you minimize the risk of microgravity, radiation, solar activity, micrometeoroids etc.

Bigelow had this (bottom) as a lunar ship concept - might have some merit for long duration missions too. That their habs can include water blankets for shielding and have many layers of Kevlar and Vectran for micrometeoroid protection is sauce for the goose.

NASA actually did hypervelocity impact testing on the TransHab tech before it was shut down and the patents sold to Bigelow. The results were so good it was proposed that the aluminum modules of the ISS be retro-fitted with TransHab-style materials for debris protection.

Bigelow then made changes of his own that appear in this patent;

Orbital debris shield
United States Patent 7204460

http://www.freepatentsonline.com/7204460.html
and
http://www.freepatentsonline.com/y2005/0284986.html

Space.com Heliosphere Explorer 1 (SHE-1) (edit 2009.08.30)
_____________________________________________________________________
1. Lander:
Start with Altair (Lunar lander), keep it in one piece (SSTO), apply COTS tricks to lower cost.
2. Habitation and logistics:
1x BA330, 1x ISS Node-1, 2x ISS PMA
3. Power source (20 MW or 20 000 kW for engines)
a.) use RTG
- RTG generator
- cooling radiators
b.) use PV
- PV cells
- batteries
4. VASIMR, fuel
- 20t argon fuel tank for 80t of argon
- 4x VX-5000
5. Supplies, instrumentation, science (edit 2009.08.31)
- 20t supplies for 6 people for 6 months
- 40t instrumentation, science, for first evaluation
____________________________________________________________________
1. = 20t
2. = 40t
3a. - using HPM (1MWe/t, text in reference speculates it could work in space, heat sink?) = 20t
3b. - using SAFE-6400 (0,083MWe/t, heat sink?) = 16 * (16 * SAFE-400) = 16 * 20t = 320t
3c. - using Solaren PV (0,72 MWe/t) = 60t (check above discussion)
- batteries or fuel cells ?
4. - 20t fuel tank + 80t fuel = 100t
- 4x VX-5000 = 4 * (25 * VX-200) = 4 * 10t = 40t
- heat sink = ?
5. 20t + 40t = 60t

(edit 2009.09.30, added equation)
http://en.wikipedia.org/wiki/Rocket_equation
Isp = 5000
Ve = Isp * g = 5000 s * 10 m/s^2 = 50km/s (edit 2009.08.31, changed g0 to g, added * multiplication symbol)
dV = Ve * ln (m1/m2)

Options:
(using rocket equation, Isp = 5000)
3a.) 20t + 40t + 20t + 100t + 40t + 60t = 280t, delta V = 16,8 km/s
3b.) 20t + 40t + 320t + 100t + 40t + 60t = 580t, delta V = 7,4 km/s
3c.) 20t + 40t + 60t + 100t + 40t + 60t = 320t, delta V = 14,4 km/s
(using rocket equation, Isp = 10000) (edit 2009.08.31, calculations for Isp 10000)
3a.) 280t full (m1), 200t empty (m2), delta V = 33647,22 m/s = 33,65 km/s
3b.) 580t full, 500t empty, delta V = 14,84 km/s
3c.) 320t full, 240t empty, delta V = 28,77 km/s
(using rocket equation, Isp = 30000) (edit 2009.09.01)
3a.) delta V = 99 km/s
3b.) delta V = 43 km/s
3c.) delta V = 84,7 km/s

Thrust assuming 60 % efficiency for 4x VX-5000 (edit 2009.09.01, expected efficiency around 80 %)
Isp 1000s = 20000 kW * 0,6 / (1000s * 9,81 m/s^2) = 1220 N (not in operational range of VASIMR)
Isp 5000s = 245 N
Isp 10000s = 122 N
Isp 30000s = 41 N

(edit 2009.08.30, added burn time)
Burn time, assuming 80t argon, using equation (fuel * Isp * g)/thrust, numbers are approximate :
Isp 1000s = 7 days (not in operational range of VASIMR)
Isp 5000s = 189 days
Isp 10000s = 758 days
Isp 30000s = 6646 days (18+ years)
_______________________________________________________________

We are missing info on heat sink (8 MWt for engines), batteries/fuel cells and radiation shielding mass. I am also avoiding cost discussion until we have stable hardware configuration.

I'm still checking the list, please comment.
______________________________________
Here are some links for reference: (edit 2009.09.01, references)

I have some assumptions about size and mass of heat sinks, but no real data yet, using this page:
http://en.wikipedia.org/wiki/Thermal_radiation

(2009 U.S. Commercial Space Transportation Developments and Concepts:
Vehicles, Technologies, and Spaceports January 2009)
http://www.faa.gov/about/office_org/hea ... 202009.pdf

Reference Guide to the International Space Station :
http://www.nasa.gov/mission_pages/stati ... Guide.html

VASIMR article on Wikipedia with lots of links:
http://en.wikipedia.org/wiki/VASIMR

This document includes information about maximum possible Isp in 30 000s range.
I have received email from Ad Astra Rocket, confirming operational Isp range from 5000s - 30000s
(edit 2009.09.02)
(VASIMR Plasma Rocket Technology)
http://dma.ing.uniroma1.it/users/bruno/Petro.prn.pdf

About nuclear option:

Seven of the nuclear generators would provide 200 MW of power to enable 39 day one way trips to Mars.

(November 28, 2007 - Vasimr engines plus 200 MW of nuclear "batteries" = 39 days to Mars )
http://nextbigfuture.com/2007/11/vasimr ... clear.html

Hyperion Power Module information:
http://www.hyperionpowergeneration.com/product.html

Link on Wikipedia to get specific energy for SAFE-400
http://en.wikipedia.org/wiki/SAFE-400

Some past projections:
(Future NASA Multi-kilowatt Free Piston Stirling Applications)

This paper describes the preliminary work that will be performed toward development of a nuclear-fission-powered nominal 30 kW Stirling power system for use on the lunar surface with a specific power goal of about 140 W/kg for the Stirling power conversion system.

http://sri.auburn.edu/papers/2006/futur ... irling.pdf

Solar alternative:
(Stretched Lens Array SquareRigger (SLASR): A New Space Array for High-Power Missions)
http://www.stretchedlensarray.com/Paper ... WCPEC4.pdf

· Areal Power Density = 300 - 400 W/m2
· Specific Power = 300 W/kg - 500 W/kg
· Stowed Power = 80 - 120 kW/m3
· Scalable Array Power = 4 kW to 100’s of kW’s
· Super-Insulated Small Cell Circuit = High-Voltage (300-
600 V) Operation at Low Mass Penalty
· Super-Shielded Small Cell Circuit = Excellent Radiation
Hardness at Low Mass Penalty
· 85% Cell Area Savings = 66% to 75% Lower Array Cost
per Watt than One-Sun Array
· Modular, Scalable, & Mass-Producible at MW’s per Year
Using Existing Capacities

Orbital Data for the Planets & Dwarf Planets :
http://www.windows.ucar.edu/tour/link=/ ... table.html

Conceptual Mars mission using 3 VASIMR engines (SHE has 100):
[youtube]http://www.youtube.com/watch?v=Zj53rVWK5z0[/youtube]

 

[neutrino78x]

you could even put a VASMIR ion engine on it, which would speed it up considerably

At this point, the VASIMR 200KW engine at full throttle pushes about as much as a medium burger with fries on your table.

Yeah but the wikipedia article you cited says that VASIMR has a high thrust mode. I read somewhere that in high thrust mode, VASMIR could get you to Mars in 39 days. That would not be at 200 kW though, more like 20+ MW... You would power it with a space nuclear reactor, in that case (most likely).

--Brian

 

[neutrino78x]

Also, there is a modification of Mars Direct, called Mars for Less, which is basically the same plan, except that it eliminates the need for heavy lift by performing orbital assembly of modules delivered via small commercial rockets. You would still use a very small craft, about the same living area as a nuclear submarine (on which I have went underway...it isn't that bad given that you are not claustrophobic), but instead of lifting everything in one launch, you would use 2 or 3 launches, and the crew would go up separately.

--Brian

 

[orionrider]

but the wikipedia article you cited says that VASIMR has a high thrust mode.

The 5Newton thrust of the current engine is on 'high thrust mode' :?

The problem of a multi-MW engine is that the nuclear reactor would be very, very heavy, which in turn would slow the whole spacecraft. Maybe one day we will be able to produce that much electricity in a lightweight reactor, who knows?

 

[EarthlingX]

but the wikipedia article you cited says that VASIMR has a high thrust mode.

The 5Newton thrust of the current engine is on 'high thrust mode' :?

The problem of a multi-MW engine is that the nuclear reactor would be very, very heavy, which in turn would slow the whole spacecraft. Maybe one day we will be able to produce that much electricity in a lightweight reactor, who knows?

A hint - what is more 1x100 or 500x1 ?

Fastest spacecraft ever :
http://www.jpl.nasa.gov : NASA's Dawn Spacecraft Fires Past Record for Speed Change

June 07, 2010

PASADENA, Calif.-- Deep in the heart of the asteroid belt, on its way to the first of the belt's two most massive inhabitants, NASA's ion-propelled Dawn spacecraft has eclipsed the record for velocity change produced by a spacecraft's engines.

At first glance, Dawn's pedal-to-the-metal performance is a not-so-inspiring 0-to-97 kilometers per hour (0-to-60 miles per hour) in four days. But due to its incredible efficiency, it expends only 37 ounces of xenon propellant during that time. Then take into consideration that after those four days of full-throttle thrusting, it will do another four days, and then another four. By the end of 12 days, the spacecraft will have increased its velocity by more than 290 kilometers per hour (180 miles per hour), with more days and weeks and months of continuous thrusting to come. In one year's time, Dawn's ion propulsion system can increase the spacecraft's speed by 8,850 kilometers per hour (5,500 miles per hour), while consuming the equivalent of only 16 gallons of fuel.

This will give you some starting points, i hope :
http://en.wikipedia.org/wiki/Hyperion_Power_Generation

20t - 20MWe.

neutrino78x can probably provide a bit of info about reactors in submarines, which might be usable in space too.

Try reading one more time the above post, this time not only looking at pictures. I tried to avoid more complicated calculations, since even this seems to be a bit too much.

There has been development with some of the references, but you can plug in new data, if you want to have informed opinion. I can also recommend reading those references, since it seems you missed that.

 

[Polishguy]

I have had this idea for a long time, so I will just throw it out there. Keep in mind, I haven't thought it out a ton so don't be too hard on me Anyway, I think, once we are ready to go to Mars, instead of building a purpose built ship to go there, why don't we build a space station using, say, Bigelow Aerospace's BA-330's and some sort of propulsion hub and some solar panels? If there were enough panels, you could even put a VASMIR ion engine on it, which would speed it up considerably. Anyway, is this just crazy talk or is it a good idea?

I'm sorry, but this plan was suggested already back in 1990-91. It was called the "Straight-Arrow Approach", or something to that effect. The idea was to assemble a 700 tonne spacecraft in LEO, fly it out to Mars on nuclear-electric rockets, spend a month in Mars orbit, and return. And it remains just as absurd as it originally did. VASIMR wouldn't save you time unless you plan on packing hundreds of tonnes of fuel (39 day flight = 660 tonnes of fuel). VASIMR could save fuel if we were to fly it with little fuel on a 6 month transit (really, why not a six-month transit? Humans can survive that long in microgravity, as proven by ISS and Mir), in which the ideal approach would be:

Launch on a single rocket your Mars Surface Habitat and a small capsule to launch from Martian surface on chemicals. Their upper stage is a VASIMR, which also brakes them into Mars orbit, where they aerobrake to the surface. They park on the surface, make O2 from the CO2 air, fuel up in methane/oxygen fuel, and wait two years until the next flight opportunity. Your VASIMR engine that pushed them then returns to Earth Orbit at the first opportunity, where it parks in orbit and waits for its next use.

Then, your Transit Habitat flies on a VASIMR engine, with a BA-330 like habitat module, and a small re-entry capsule for Mars landing. It parks in Mars orbit, and the small capsule lands on the surface with your crew of four-six. They do their science for two years. At the end of that, your Transfer Habitat flies around, almost to Mars Escape Velocity. Then, your crew on the surface boards their small capsule, and fly with their chemical engines to rendezvous with the Transfer Habitat right before it reaches Escape. Then they fly back to earth. The purpose of rendezvous so close to escape is to save a month of transfer time (the crew will spend time on the surface, rather than doing nothing while the Trans Hab flies out).

However, this assumes that you want to use VASIMR engines and reuse them. If you want to save money and do a Mars Mission in ten years or less, then you'll do a Mars Direct flight with all chemical engines (purpose-built return vehicle, habitat that your crew spends the outbound flight and surface stay in, methane/oxygen return fuel) and save yourself the development time.

 

[Valcan]

but the wikipedia article you cited says that VASIMR has a high thrust mode.

The 5Newton thrust of the current engine is on 'high thrust mode' :?

The problem of a multi-MW engine is that the nuclear reactor would be very, very heavy, which in turn would slow the whole spacecraft. Maybe one day we will be able to produce that much electricity in a lightweight reactor, who knows?

A hint - what is more 1x100 or 500x1 ?

Fastest spacecraft ever :
http://www.jpl.nasa.gov : NASA's Dawn Spacecraft Fires Past Record for Speed Change

June 07, 2010

PASADENA, Calif.-- Deep in the heart of the asteroid belt, on its way to the first of the belt's two most massive inhabitants, NASA's ion-propelled Dawn spacecraft has eclipsed the record for velocity change produced by a spacecraft's engines.

At first glance, Dawn's pedal-to-the-metal performance is a not-so-inspiring 0-to-97 kilometers per hour (0-to-60 miles per hour) in four days. But due to its incredible efficiency, it expends only 37 ounces of xenon propellant during that time. Then take into consideration that after those four days of full-throttle thrusting, it will do another four days, and then another four. By the end of 12 days, the spacecraft will have increased its velocity by more than 290 kilometers per hour (180 miles per hour), with more days and weeks and months of continuous thrusting to come. In one year's time, Dawn's ion propulsion system can increase the spacecraft's speed by 8,850 kilometers per hour (5,500 miles per hour), while consuming the equivalent of only 16 gallons of fuel.

This will give you some starting points, i hope :
http://en.wikipedia.org/wiki/Hyperion_Power_Generation

20t - 20MWe.

neutrino78x can probably provide a bit of info about reactors in submarines, which might be usable in space too.

Try reading one more time the above post, this time not only looking at pictures. I tried to avoid more complicated calculations, since even this seems to be a bit too much.

There has been development with some of the references, but you can plug in new data, if you want to have informed opinion. I can also recommend reading those references, since it seems you missed that.

From what i remember reactors on subs wouldnt help a they rely on the sea and require gravity.

However there is also pebblebed reactors so...

 

[MeteorWayne]

Valcan, please read my PM to you. There is no need to quote 5 paragraphs of text to address one issue in the post.

 

[HopDavid]

I read somewhere that in high thrust mode, VASMIR could get you to Mars in 39 days.

That assumes a power source that masses half a kilogram for each kilowatt. Kirk Sorensen calls this a magical fantasy power source.

This was discussed extensively in the Nasa Spaceflight Forum thread "Role of NTR/BNTR/NEP in future architectures"

Here are a couple of Sorensen's posts from that thread:
0.5 kg/kWe number is a fantasy
Yeah, that's the magic number right there.

I believe Sorensen worked for NASA for a number of years where nuclear electric propulsion was one of his major interests. One of his big goals was lightweight, powerful power sources. I suspect that was a major motivation for much of the thought and research behind his website Energy From Thorium.

I have to confess I was quite skeptical when I read about the 39 day Mars trip. I respect Sorensen's opinion and I wasn't surprised when he declared PCD's power source to be a fiction.

 

[neutrino78x]

From what i remember reactors on subs wouldnt help a they rely on the sea and require gravity.

I was a sonar tech, but on submarines, everybody is required to learn certain things. Although, one patrol, the XO asked me why it was that I had more radiation exposure than anyone in the forward compartment (non-nuclear operators: sonar, radio, torpedomen, etc.). lol ;-) It was because I went back there more often than strictly necessary, to check it out, being interested in physics. Don't worry I did not get excessive exposure, just more so than anyone in the forward compartment that patrol. We used to refer to radiation, like gamma rays, as "zoomies" lol. Regardless, yes, you are correct, the reactor on the boat uses sea water for coolant, and it requires gravity. Plus, while the reactors on submarines are relatively small, they are still much larger than anything we would put in space in the near future.

See this layout of a USN Trident submarine (Ohio class), which was taken from this civilian web site (the navy puts this diagram out in booklets it gives to people who take tours but don't have a clearance). The crew sleeps in between the missile tubes; there are bunkrooms where 9 men sleep in each one. You can see that the engine room obviously has a lot of equipment supporting the reactor that you are not going to launch into space right now. This is what the boat looks like IRL from above. The Engine Room LET (hatch) is visible just aft of the men standing in between two of the mooring lines securing the tugboat to the submarine in the top of the photo. You might wonder, why doesn't the USN identify where the actual reactor is in that diagram? That is because it is classified. We don't want the Russians/Chinese to know the layout of equipment there.

I think the ideal nuclear rocket might be that bimodal nerva they talk about on Atomic Rocket. Set it up one way, and the coolant gets exhausted out the back as fuel, but once you are done with your burn, you don't shut down the reactor, you just turn some valves, and the coolant just circulates in the reactor, generating electricity for your ship.

See the Atomic Rocket entry on NERVA (scroll down to bimodal NTR).

--Brian

 

[orionrider]

At this point, unless some skunkworks lab has a secret and tested solution, it looks like the 2035 mission to Mars will be chemical. I think that, at least for the short to medium term, VASIMR will be used for long duration probes, solar or RTG powered.


BTW, the Hyperion website gives a 'less than 50 ton' mass for the reactor ('Hyperion Power Module'), 20 ton on the wiki.
But what about the turbine, generator, condenser, evaporator, condenser, control equipment, piping, secondary fluids,...? The whole power plant would be much heavier and require a sizable crew to operate. Even if the core is self-contained and automatic, things like alternators, pumps and turbines need periodic maintenance and spare-parts.

 

[neutrino78x]

At this point, unless some skunkworks lab has a secret and tested solution, it looks like the 2035 mission to Mars will be chemical. I think that, at least for the short to medium term, VASIMR will be used for long duration probes, solar or RTG powered.

Yes, I agree with this.

BTW, the Hyperion website gives a 'less than 50 ton' mass for the reactor ('Hyperion Power Module'), 20 ton on the wiki.
But what about the turbine, generator, condenser, evaporator, condenser, control equipment, piping, secondary fluids,...? The whole power plant would be much heavier and require a sizable crew to operate. Even if the core is self-contained and automatic, things like alternators, pumps and turbines need periodic maintenance and spare-parts.

That's what I was saying with my post about submarines. The reactor vessel itself is small, but there is more to the power plant than the vessel. btw, the room called "maneuvering", where they operate the reactor, has a special door on it that is supposed to remain closed most of the time underway. You have to ask permission to enter, and state your reason for entering. That room is special because, in the event of a steam line rupture, everyone else in the engine room would die nearly instantly, but the special thermal lining in maneuvering allows them to survive for 5 minutes or so, long enough to shut down the reactor and save the lives of everyone else on the boat. Just one of many reasons why the crew of a submarine is considered an elite unit.

Regardless, a space nuclear reactor would be totally different. You would want a form of power conversion from heat to electric that used far fewer moving parts.

Here is the wikipedia on the SNAP 10A reactor which was actually flown in space.

This page with more detail says it generated 600 watts.

So the SNAP generated 600 watts but it weighed 650 pounds (unshielded). A lot lighter than the hyperion but a lot less electrical output.

Here is the "SAFE" space reactor.

 

[orionrider]

Looks like the Russians believe in nuclear propulsion:

http://www.vaec.gov.vn/userfiles/file/N ... 2_2010.pdf
http://www.world-nuclear.org/info/inf82.html
(had to pull the google cache since it did not load on my laptop)
"Nuclear Reactors for Space"

In 2010 the Russian government is to allocate RUR500 million (about US$170 million) of federal funds to design a space nuclear propulsion and generation installation in the megawatt power range. In particular, SC Rosatom is to get RUR 430 million and Roskosmos (Russian Federal Space Agency) RUR 70 million to develop it. The work will be undertaken by N.A. Dollezhal NIKIET (Research & Development Institute for Power Engineering) in Moscow, based on previous developments including those of nuclear rocket engines, but beyond that the design envisaged is not known. A conceptual design is expected in 2011, with the basic design documentation and engineering design to follow in 2012. The life-service tests are planned for 2018.

 

[neutrino78x]

Looks like the Russians believe in nuclear propulsion:

Yep. I do also! It needs to be developed. We need a light, safe nuclear reactor, that can be launched from earth non-active, and is entirely safe in the event that the rocket blows up on the launch pad or on the way to space.

Actually, ideally, and this is for the farther future, if we could build the reactors in space in the first place, I doubt anyone would complain about that.

But I agree with you, orionrider: for the near future, most things in space will be powered either by solar or RTG. A nice safe, small reactor, though, as I said above, would be a big breakthrough.

--Brian

 

[Valcan]

Looks like the Russians believe in nuclear propulsion:

Yep. I do also! It needs to be developed. We need a light, safe nuclear reactor, that can be launched from earth non-active, and is entirely safe in the event that the rocket blows up on the launch pad or on the way to space.

Actually, ideally, and this is for the farther future, if we could build the reactors in space in the first place, I doubt anyone would complain about that.

But I agree with you, orionrider: for the near future, most things in space will be powered either by solar or RTG. A nice safe, small reactor, though, as I said above, would be a big breakthrough.

--Brian

Obviously you have more faith in humanity than I. People can complain about ANYTHING.