Wednesday, January 14, 2004

At the Crossroads

An interesting article from Yahoo details the different and contending visions for the next decades in space exploration. Some, like Paul Spudis of Johns Hopkins Applied Physics Laboratory, believe the emphasis should be on making exploration self-sustaining by using extraterrestrial resources to go stages further. The successful achievement of these goals would be equivalent to European settlers in the New World harvesting crops for the first time instead of relying on imported provisions from England.

"If I were advising the President, I would suggest that he declare that the mission of this new effort is to develop the technologies and techniques to mine, process, and use lunar resources, specifically, the hydrogen and oxygen of the lunar poles," Spudis told . ... "If we can break the bonds of Earth and re-fuel our spacecraft, both interplanetary and Earth-orbital, our whole way of doing business in space will be forever changed for the better. Our limitations will no longer be driven by the capacity of our launch vehicles, but by our own imaginations," Spudis concluded.

Mike Duke, a space resources expert at the Colorado School of Mines in Golden, explained how this might work.

Propellant cranked out by this system, Duke added, would be sufficient to reduce the need for launch capability from the Earth by at least a factor of two for a round trip mission to the Moon and a factor of four if a refueling depot is established at the L1 Lagrangian point in deep space. A Lagrangian point is a spot at which a small body, under the gravitational influence of two large bodies, will remain somewhat at rest relative to them. "That is a clever way of doing it, not just depending on brute force, and it would have ramifications for Mars, as well as potential commercial benefits," Duke advised.

Robert Zubrin, head of the Mars Society, is not willing to wait on events. He believes that an actual manned landing on Mars, not a Mars orbital mission, must be the goal of the coming decades. "The Mars mission must actually go to Mars. Missions that simply fly by Mars, go into Mars orbit, or to the Martian moons are insufficient," Zubrin stressed. "The purpose of sending humans to Mars is not to set a new altitude record for the aviation almanac. The purpose is to explore and pioneer a new world. This can only be done with astronauts on the Martian surface."

Jack Schmitt, one of the last men to walk on the moon, also de-emphasizes the getting there, focusing on how to do it sustainably and economically.

Schmitt said that going to the Moon accelerates going to Mars in a number of ways. Just for starters:

  • you get a low cost, heavy lift booster into the inventory, perhaps largely paid for by private investors if you do it right;
  • you get helium-3 fusion technology that can be adapted to an Earth-orbit to Mars-orbit continuous acceleration-deceleration rocket;
  • you get lunar hydrogen, water, oxygen and food to reduce the Earth launch mass until a Mars settlement is self-sufficient;
  • you get Mars surface facilities designs derived from lunar designs that will have indefinite life engineered into their construction and maintenance strategies; and
  • you get experience in working in deep space again, a much less forgiving environment than earth-orbit.

While Spudis, Duke and Schmitt are making knowledgeable estimates of the technology that may be available in the coming decades, none of these are mature and certified systems today. Adopting their approach creates a roadmap to Mars without specifying the estimated time of arrival. But if the engineering objective is to land men on Mars within two or three decades,  as Zubrin suggests, preparation must begin on the basis of current technology, such as the Mars Direct plan. A space vision whose objective is primarily getting a payload to Mars will yield vastly different results from one aimed at developing the means to get there. Of course, the two efforts interact. Yet, as Belmont Club argued in the The Beckoning Sky, success may depend on the timing and preparation of the effort as much as in the hardihood of attempting it.

Europe, Japan and China have showed a renewed interest in interplanetary travel, just as domestic liberals have evinced a horror of it, as a spending distraction from their pet social programs. The danger in committing money to the voyage, rather than to technological preparation, is that America's competitors may steal a march in really critical areas. America was not settled by the European power which reached it first, but by that which sustained its presence. At the other extreme, the danger in waiting too long is that the vision may languish, or that America's astronauts may find, like Scott at the South Pole, another flag already waving there.