The endless debate over NASA’s next destination resembles a food fight between the Moonmen and the Mars advocates. The near Earth asteroids get no respect from either side. That lack of respect seems kind of strange, considering some near-Earth asteroids have a potential ability to destroy all life on Earth. One would expect that sort of death-dealing ability to merit at least a little respect. Nevertheless, near-Earth asteroids are ridiculed as mere “rubble piles” and any proposed visit is a “mission to nowhere.”

Ultimately, this debate is silly. The only real answer to the designation question is “All of the Above.” If we develop low-cost access to space, supporting infrastructure such as propellant depots, and deep-space exploration exploration ships like JSC’s proposed Nautilus-X, we can go anywhere in the solar system. Without such capabilities, we’re going nowhere.

Having said that, let’s play the destination game just this once. We’d like to put in a pitch for a dark horse candidate.



The main-belt asteroids are seldom mentioned as potential targets for human exploration. There’s a good reason for that. The main asteroid belt is quite a ways off – on the other side of Mars – and if one wants to visit an asteroid, there are plenty of candidates in the near-Earth zone.

One main-belt asteroid stands out as an object of interest, though: the largest of the asteroids, Ceres. In fact, some planetary scientists don’t consider Ceres an asteroid at all but a dwarf planet, which may have been formed by a different process. In either case, Ceres is definitely interesting – the sort of place NASA should consider going.

Ceres is only about 1% the mass of the Moon, but has a surface area 7.5% as large as the Moon’s. That might not sound like much, but it’s an area 10 times the size of Texas. It’s also 10 times the total surface area of the Great Lakes. Beneath the thin, dusty surface covering is a layer of water ice that’s estimated to be 45-75 miles deep – 6-10 times as deep as any ocean on Earth. That’s a huge potential resource, larger than the total volume of fresh water on Earth, and dwarfs the amount of water which lunar scientists optimistically hope to find on the Moon.

More intriguingly, Ceres may not be a dead world. It has been suggested that Ceres may still have hydrothermal activity and even liquid oceans beneath its frozen crust. If that’s the case, then Ceres, like Europa, might even have life. In fact, Ceres might be a more promising abode for life than Europa, which orbits within Jupiter’s powerful radiation belts. Astrobiologists are now trying to determine how deep life would have to be to survive on Europa. Ceres has no such problem.

Considering the formidable technical problems involved in building a probe that can travel all the way to Europa, operate within the radiation belts, and still drill through miles of ice, it might make more sense for astrobiologists to check out Ceres first. Especially if the complexities of the drilling project prove too great for robots alone and require humans for on-site supervision.

Do we believe Ceres will be the next destination humans visit inspace? No. Ceres is not as far away as Europa but it is considerably farther than the Moon, the near-Earth asteroids, or even Mars. We can debate the merits of chemical versus nuclear propulsion for human missions to Mars, but Ceres clearly requires some sort of nuclear or electric propulsion. Nevertheless, it is worth keeping in mind as a mid-term option.