Thursday, December 31, 2009
This is a tough decision. NASA will be giving out a $650 million grant to an upcoming mission and has narrowed the field to three proposals - either a probe to the surface of Venus, a probe that would bring back some material from a permanently dark crater on the Moon, or one that would bring back samples from a primitive asteroid.
Personally I prefer the Venus surface mission, but from a long-term point of view missions to the Moon are probably more helpful since whatever helps us to establish a foothold there will be good for us as a whole, including using it as a stepping stone to other parts of the Solar System. This chart shows just how much - delta v from Earth to LEO is 9.3 - 10 km/s, whereas from the Moon to lunar orbit is a mere 1.6 km/s, and after that is achieved then the rest of the Solar System is pretty easy. That much of a difference in delta v means that a craft can either use a much smaller rocket and less fuel (lower cost), or use the same sized rocket but achieve a much greater velocity, or some combination of the two. The Moon would be a nice launching point for low-budget basic probes that would fly by certain targets that otherwise would be too expensive for a mission launched from Earth - a tiny probe launched to fly by an asteroid as it approached the Earth-Moon system, a tiny probe launched toward an object in the asteroid belt for a cheap flyby.