New Mars Forums

What makes nuclear power so special?  In my mind, there are three things: energy density, no toxic chemical emissions, and dependability.  Coal has a decent energy density and it can be burned 24 / 7, but it's too bad for us and our environment.  Solar and wind, while the best for our environment, have poor energy densities, and they fluctuated based on the weather and time of day.

Energy density and dependability make nuclear power ideal for spaceflight.  It will be much cheaper and easier to put a reactor or two on your spacecraft instead of the colossal solar arrays (see the Energia plan for putting humans on Mars.) And batteries would be needed when the sun goes down, necessitating the use of heavy batteries to store the excess power generated during the day.

It's time to cut the crap.  Logic must emerge victorious over demogoguery.  Make mine nuclear power.

That's a pretty big decision to make.  This summer's Russian proposal used ion engines, but it enabled a two-year mission with only 30 days to stay on Mars.  On the other hand, VASIMR plasma engines may allow 90-day transits each way with stay times of similar duration to the transit.  VASIMR is the more promising "high risk, high payoff" technology that will make Mars achievable.

If Apollo were revived as suggested, it would be the re-entry capsule only.  A small de-orbit rocket would be fitted instead of the service module.  Weight of the capsule would be kept down through advances in materials over the last 40 years.

I think that lifting bodies or space planes are better for crew taxi to ISS, but they're too heavy to bring people back from Mars.  Along the same note, you would need two Soyuz to bring a crew of 4-6 back from Mars.  Desite its extra weight, Apollo remains the superior spacecraft for an earth re-entry vehicle.

Some thoughts on China's space program...

1. China will have a man in space by spring 2003, and I don't think anyone doubts that.  Shenzhou 5 may even be a two-man flight.

2.  In its early stages, the Chinese space program will be limited by funding shortages, but that will change as the program's propaganda value is realized and China becomes a superpower.

3.  The moon is China's logical goal within the next twenty years.  The only appropriate action for NASA, RSA, and ESA is to launch a competing moon effort in order to stimulate the stagnating space programs.

4. China will not militarize space unless the United States launches some kind of military spaceplane or space laser.  The military value of China's space program comes from "dual use" technologies--like maneuverable missile reentry vehicles and guidance systems.

An all-new booster might be the way to go, especially if you can build a modular heavy-lifter (in the spirit of Delta IV and Atlas V.)  But doing so requires research and development money that just doesn't exist right now.  The scarcity of funds keeps Shuttle-C in contention to be the Mars rocket of choice, and that will not change for a while (on the bright side, a large portion of NASA's R&D is being spent on nuclear propulsion.)

The U.N. didn't approve the No-Fly Zones?

Only Iraq has rejected the legitimacy of the no-fly zones.  And I think Saddam welcomes them, because it gives him a chance to shoot down an American plane and score a big propaganda victory.

The no-fly zones have strengthened Iraq's desire to wage war with the United States and support the Wahabbis in thei war with the United States.  But the no-fly zones have also given Kurds and Shiites a safe haven from which a rebellion could begin.

I'm starting to to favor the Shuttle C over Ares for the Mars rocket.  On problem with Ares has to do with the current ET: it's not designed for the bending momnets created by a payload mounted on top of the vehicle.  Some strengthening will probably be required.

I'm thinking that Shuttle-C can be justified economically by launching several satellites on one shot, reducing redundant mission costs for the multiple launches of smaller rockets required for the same payload.

Of course, such a plan requires that a LOT of satellites need to be launched into the same orbit.  Using a Shuttle-C to loft multiple satellites in today's market could actually be disastrous because it would REDUCE demand for launchers.

A recent issue of "The Futurist" summed up space tourism (and all of commercial space) like this: costs will come down when there is a demand to commercialize space.  Demand will increase when costs come down.  The solution to this catch-22 is some enabling technology that will both reduce cost and increase demand.  That's why I'm so enthusiastic about the X-Prize.

NASA is a HUGE corporate welfare engine, consuming $15 billion a year and a MASSIVE 1% of the federal budget.

NASA's primary job is still space exploration, the only problem is that politicians don't understand that.  Take Apollo as an example.  The scientists, engineers, and astronauts all believed in their research and the value of new knowledge.  The projects supporters in Congress could have cared less; President Johnson used it to justify pork-barrel spending in Texas when the Manned Spaceflight Center could have been built at Cape Canaveral like everything else.

Because NASA is a government organization, it must exist as both a scientifc and political entity.  If we want to make a group firmy-committed to space science, we'll have to wait until research institutions can afford space travel--which requires the commercialization of space.

Funny that you should mention scramjets and RBCCs.

I have some hope that air-breathing engines will drastically reduce the cost of space.  However, Rand Simberg, my personal hero, seems to think that the depressed trajectories of air-breathing spaceplanes negate the benefits of not carrying an oxidizer.

With that being said, developing an RBCC should still be a priority.  Even if they aren't good for spaceplanes, they would still be useful in Mach 6 bombers and "Orient Express" airliners.

The shuttle MLP was actually modified from the Saturn V MLP, which had a completely different engine configuration from the shuttle.  I don't think it would be too impractical to modify one of the two MLP's for a shuttle-derived booster.

I also think that we should move away from reliance on the MLP.  The Energia transporter system allowed for faster transport (by a launchpad on rails) to the launch site, and the booster was transported in a horizontal fashion, which is easier from a mating, boarding, and checkout standpoint.

I don't see too much of a problem modifying the Shuttle ET for an upper stage.  Instead of using the ogive LOX tank on the original ET, just use a shortened hydrogen tank, with common hemisphere bulkheads from the ET hydrogen tank. 

Side-mounting the engines may have some benefits, even if the MLP is modified or discarded.  It allows for an aft cargo container (ACC) on the end of the ET, and the ACC can hold equipment and stores for modifying the ET into a habitable module.

Our ability to launch anything to the Moon, Mars, or outer planets is limited by the 24 tonne limit of existing boosters (Shuttle, Titan IV, Delta IV.)  On this forum we have established that resurrecting the Saturn V or Energia is possible but not practical due to the presence of shuttle technologies that will help us build something bigger.

Zubrin's Ares is an outgrowth of previous Martin studies for Shuttle-C, an unmanned cargo rocket using shuttle boosters and ET for the 0th and first stages.  Ares carries its payload on an upper stage, although the official Shuttle-C studies carried it in a lateral payload canister which housed the engines.

According to David Portree's Romance to Reality, Martin actually planned to use Shuttle-C to make an "EELV," like the Delta IV heavy.  Three ETs with attached angines would be mated side to side with an upper stage on top.  Six advanced SRBs would give the ET booster some help off the ground.

Today we have the tools to make it all possible.  The RS-68 is cheaper and provides more thrust than the SSME.  The Shuttle ET is lighter.  The French Vulcain 2 engine is the perfect size for the upper stage of the Shuttle-C rocket.  Fabricating extra ETs and SRBs for the Shuttle C will also bring down launch costs for the standard Shuttle.

It's time we go ahead with Shuttle C.  If only NASA had the guts to commit to a manned Mars mission.