President George Bush may announce the plan, named Project Prometheus, at his State of the Union address on January 28, according to a report in the Los Angeles Times. It would commit the US to the exploration of Mars as a priority and herald the development of a nuclear-powered propulsion system. The first voyage could take place as soon as 2010.
"We're talking about doing something on a very aggressive schedule to not only develop the capabilities for nuclear propulsion and power generation but to have a mission using the new technology within this decade," said Nasa administrator Sean O'Keefe.
The most gratifying aspect of this proposal is the underlying attitude at NASA that is driving the nuclear propulsion approach. NASA has spent the last couple of decades trying to patch up yesterday's technology (the loser space shuttle) rather than try to make technological leaps that would make space exploration more affordable and feasible. Now NASA wants to work on enabling technologies.
The new rocket proposal also represents a significant change at the agency, which has typically been driven by a quest to get somewhere -- the moon, Mars or the outer planets in the solar system -- and then developed the technologies to do so.
Instead, O'Keefe has begun shifting the agency's focus to developing so-called "enabling technologies" to carry out missions whatever they might be.
NASA is now denying that Project Prometheus will be announced in the President's State of the Union address. But NASA may be backpedalling in order to allow the President to make the official announcement.
"At this point I can't say what they plan beyond what we announced in the 2003 budget," Savage said.
"O'Keefe didn't say that there would be announcement in the State of the Union concerning NASA. He doesn't know what's going to be in the State of the Union and certainly wouldn't get out in front of the President," Savage responded to SPACE.com.
This is not as sudden a decision as it might seem. NASA decided to reactivate its nuclear propulsion program a year ago.
ALBUQUERQUE, NEW MEXICO – For the first time in a decade, NASA has been given the go-ahead to say the “N” word – nuclear power for space.
The White House-backed NASA budget for fiscal year 2003 includes a major nuclear systems initiative that sets the stage for faster trip times by spacecraft exploring the solar system and powering human outposts on distant worlds.
If a nuclear propulsion program is going to be used to go somewhere the logical first stop is obviously Mars. Serious discussions in NASA of a nuclear propulsion mission to Mars were reported by Space.com to have started back in 2000.
In the past few months, several NASA notables, including associate administrators Joe Rothenberg and Gary Payton, have mentioned publicly that nuclear power in space transportation deserves a closer look. The comments indicate that if public relations efforts can gain acceptance for the possibility, future interplanetary missions may include nuclear-power options.
The NASA proposal is not for a rocket that a series of nuclear explosions made behind a shield on the back of the spacecraft (ala Niven and Pournelle's Footfall). Rather, the idea is to use a nuclear reactor to heat hydrogen propellant and then expel it behind the spacecraft at a high velocity.
In NTP, a compact lightweight nuclear reactor heats hydrogen propellants to a high temperature, e.g., 3000 K. Because the molecular weight of hydrogen is almost a factor of 10 smaller than the molecular weight of hydrogen/oxygen combustion products, the exhaust velocity of hot hydrogen propellant is much greater than that of hydrogen/oxygen. A NTP engine can achieve a hydrogen exhaust velocity of 10 kilometers/sec. and a maximum Delta-V increase in rocket velocity of ~22 kilometers/sec.
Also see this previous post in nuclear powered spaceships.
Update: Bruce Moomaw has written a follow-up article in SpaceDaily.com claiming that Peter Pae of the Los Angeles Times confused talk of a Nuclear Electric Propulsion system for space probes with a much more expensive and longer term development effort needed to build a Nuclear Thermal Propulsion system for a human trip to Mars program.
Peter Pae, in his Times article, seems to have been completely confused by O'Keefe's references to the fact that such a vastly larger nuclear-rocket system could indeed send a manned ship to Mars in only a couple of months, and so falsely connected them to O'Keefe's simultaneously declared indications that the Bush Administration does intend to considerably increase the current spending level on the NEP program while renaming it "Prometheus".
At this point it sounds like Bush will not announce a Mars mission or even the development of a nuclear propulsion system for a Mars effort. Instead the Bush Administration is going to increase funding for a nuclear propulsion system more suited for space probes. This will allow the development of much more ambitious unmanned space exploration missions. But its not going to enable the development of a spacecraft that can make a faster trip to Mars.
Update II: Bill Emrich of NASA Marshall Space Flight Center is proposing a way to make a fusion reactor (as compared to the fission reactor designs proposed for NTP and NEP designs mentioned above) for spacecraft propulsion.
Emrich is proposing a bold solution. He wants to use microwaves to heat the plasma to 600 million kelvin, triggering a different kind of fusion reaction that generates not neutrons but charged alpha particles - helium nuclei. These can then be fired from a magnetic nozzle to push the craft along.
If NASA wants to advance the state of technology for doing manned spaceflight then the development of more advanced propulsion systems should be at the top of its list of priorities. If it was up to me I'd axe the International Space Station and the Shuttle and take all the money being spent on them and spend that money on the development of nuclear fission and fusion propulsion systems. In the short term less would be accomplished in space. We'd have fewer news events with video of astronauts floating around in and outside of space structures. But NASA is accomplishing very little in either science or in technological advance with its current efforts. Rather than spend so much doing so little with yesterday's technologies NASA ought to take bigger steps and choose long term payoffs over short-term photo-ops.
|Share |||Randall Parker, 2003 January 19 09:59 AM Space Exploration|