zergnerd":2l6ypk86 said:
BA330 modules are not mature technology. Why do you need ten of them? why do you need to spin them?
Bigelow Aerospace has proven that inflatable modules are practical with their Genesis modules. They are planning to put Sundancer in orbit in 2012 I believe, which will validate all the life support systems and hold a crew of 3. Their time line is mostly determined by funding and manpower, I understand, rather than by fundamental technical issues. Since, in practicality, the first launches wouldn't begin until the 2018 to 2019 time frame, BA330 will likely be online by then. Why 10? Lab space mostly. If we're going to do exploring, we might as well have the scientific equipment to improvise new experiments based on discoveries we make. It will also give room for decent medical facilities (e.g. cat scan machine, operation table) as this is one major impediment to long term space travel. I'd envision a crew size of about 10-15 people.
Bigelow has only proven that the thecnology works in space over an extended period of time. That is good, but such modules are not going to be any cheaper than rigid ones. So why use them?
If you are talking about 10-15 people you would need two of three BA330 modules. That is more than enough volume for decent lab space and medical facilities.
Why 10 MW? Why a Breeder reactor? You are aware that the technology for a 10 MW reactor in space does not exist? And that it is about a thousand times more powerful that the most powerful reactor ever flown in space.
The technology exists but has never been put into space for political reasons, I believe. We have plenty of reactors on subs and the above mentioned Hyperion system that could be adapted for space. The largest generator in space I know of is the Cassini RTG. IMO comparing an RTG to a modern reactor is sorta like comparing a coal steam engine to internal combustion and then claiming that cars can never be made practical. They wouldn't be if we we're still using steam engines. These small reactors aren't the breeder type, but would work for a single mission. For multiple missions we'd want to adapt breeder technology to a size / weight comparable to the Hyperion. Why? If a rocket launch with a nuclear reactor ever fails to reach orbit you can kiss reactors in space goodbye for the next 50 years. If a rocket launch with inert U-238 ever fails, its not a big deal. Japan (Mitsubishi) and India are the main countries researching and using breeder technology. I am not aware of any portable units. I guess we would need a non-breeder reactor, unless we started reactor development now and planned to launch after 2030. I still think nuclear reactors could be used for $3 billion, rather than $300 b.
Breeders exist for one purpose, to breed nuclear fuel. The only reason to have one in space would be to make fuel elements, this means you need to develop orbital fuel handing, fuel reprocessing, and waste disposal. Such technology is not even remotely on the horizon.
Terrestrial reactors, be they for electrical power of ships, are no good for space. Space reactors need to be much more compact, have much higher power outputs, have operate in microgravity. and require quite different cooling technolgies.
Small nuclear reactors have flown in space, these were all less and 10 kW or so, mostly connected with the Sviet radar satellite program. They are about a thousand times smaller than what you are proposing.
VASIMR is not mature technology. It exists only as a bench top test unit. It has never been flown in space, there are serious questions about its practicality, and would need to be upgraded by a factor of about 10,000 to even appraoch what would be needed for a Mars mission. It is nowhere near "mature technology".
The main problem I have heard voiced about VASIMR is power availability. Only nuclear can supply the power needed to generate decent thrust. My understanding is that NASA plans to add a prototype VASIMR drive to the ISS for station orbit maintenance in 2012 using the station solar panels to provide power, so it can't be too immature. I assume your 10000 factor upgrade is to allow surface to orbit launches with VASIMR. This would never be practical, however, orbit to interplanetary flight should be very reasonable
Power supply is an issue for all electyric propulsion system. One advantage they have over (for exxample nuclear thermal) is that they can be scaled from small station keeping units all the way up to ones capable of sending people to Mars in a few months. Nuclear probably is the only viable option for the big ones, but there is the problem, the engineering of building space reactors that can supply megawats of electricty (and dispose of 10s of megwatts of heat) are huge. Plus all the issues of space-qualifying VASIMR and then scaling it but by three to five orders of magnitude.
The ISS will be long gone b y the time we have this type of technology.
The ISS is slated to be around until 2015. You would have to plan a lifetime extension for another decade at least. I have heard talk of extending it, but don't know the proposed duration.
Hopefully the ISS will be round until after 2020. But it is going to be a long time after that before the technology you are talking about will be available.
Nobody is using Orion to take people to Mars. It's a ferry. Bigelow modules aren't ferrys. You can't compare two very different spacecraft.
Agreed, Orion is a ferry. This simply means actual costs will be even higher once you build the Ares compatible habitation vehicle.
Of course, but it will still be cheaper than the SF mission you are proposing.
Where is your lander, surface support equipment? They are substantial items.
I don't really have an interest in Mars and would much rather visit an asteroid or orbit a gas giant. Hence, the lander costs become much smaller.
Why are you contributing to a Mars mission thread then?
I did forget to include lander costs. You would need a reusable lander.
Why resuable?
Assuming you visit a gas giant you would have ready access to water, ammonia and other volatiles from which fuel could be made.
Doing this is much more ambitious than going to Mars and will cost a lot more. It requires a great deal more conceptual technology as well.
I don't know what such a lander would cost, but it would be similar to the Apollo moon landers and could probably be done for less than $5 billion.
The Apo0llo landers were not reusable, could operate only on the Moon, did not use ISPP, offer much in the way of radiation protection, and had an endurance of obly a few days. Whay you propose is much more sophisticated and therefore expensive than Apollo.
I still think such a mission could be done for under $50 billion. Much less than what is proposed using Ares /orion / etc.
There is no way that something that requires vastly more complex and in many cases completely undeveloped technology is going to be cheaper than DRM 5.0 which uses much more extant technology.
The main problems are political, not technical. Many of the products needed exit development (mature) in the 2010 -2015 time frame, so it's unlikely we'd see things completed until the 2020 - 2025 time frame.
There are considerable technical propblems associated with developing multi-megawatt space reactors and electric populsion systems, not to mention ISPP on the Moons of Jupiter or the asteroids. Much more than with Mars.
Ultimately, I don't think the political will exists to do this as the primary goal of the current Ares program is to satisfy political constituents and keep jobs in the congressional districts that supported the shuttle.
Evidence?
After all it wasn't the Spanish people who ponied up for Columbus's crazy idea (they thought it was impossible), it was funded by a rich king and queen who hoped to get even richer and immortalize their names and who could ignore red tape. Most likely this will someday be done by a Bill Gates-type, or by some rich sultan in Arabia. But that won't happen until the price drops from $50 billion to under $15 billion or we find something out there that makes it worth their investment.
The world has changed a lot since the 15th century.
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