Asteroid Missions May Replace Lunar Base Plans

An anonymous reader alerts us to a story about efforts to modify the United States' space exploration plans to focus on asteroid missions rather than a lunar base. Scientists, astronauts, and former NASA division directors will be meeting next month to develop an alternative to the Bush administration's Vision for Space Exploration. We have previously discussed the possibility of a manned asteroid mission. Quoting: "Numerous planetary managers told Aviation Week & Space Technology they now fear a manned Moon base and even shorter sorties to the Moon will bog down the space program for decades and inhibit, rather than facilitate, manned Mars operations--the ultimate goal of both the Bush and alternative visions. The first lunar sortie would be flown by about 2020 under the Bush plan. If alternative-vision planners have their way, the mission could instead be flown to an asteroid in about 2025."

Comments

A great idea

[Phil Karn]

If true, this is very good news. Asteroids, the smaller and more numerous ones being undifferentiated bodies, have considerably more scientific value than the moon. It's actually much easier to rendezvous with and return from many asteroids than to land softly on the moon and return. The moon is relatively large, with a big gravity well, and without an atmosphere, aerobraking is impossible. Landing from lunar orbit and takeoff to orbit each require delta Vs greater than 2000 m/sec. Entering and leaving lunar orbit takes even more. Asteroids require earth escape, but that is only slightly more than reaching the moon's high altitude (400,000 km). The velocity change required to rendezvous with the asteroid could be minimized by careful choice of asteroid and launch window.

Asteroids would take much more time to reach, and a mission could not be quickly aborted in an emergency. The communications lag would also be significant; real time conversations would be impossible and communications might even be blocked entirely by solar conjunction for a few days at a time. These are challenges for human space flight, but not insurmountable ones.