I have to say, I’m a little disappointed by NASA’s announcement yesterday about its next big space venture. The American space agency and its European counterpart will team up for a joint mission to Jupiter, the largest planet, and its moons. Each agency will each launch their own satellite in 2020 to reach the fifth planet by 2026, where they’ll split up the observations of the planet and moons.
I’m thrilled that we’re going back to Jupiter. Of all of the planets in the solar system to visit, Jupiter has so many features that are begging for closer study. The diverse moons around the planet make up its own miniature solar system. Starting out, the largest one, Ganymede, is bigger than the planet Mercury, and thought to have a liquid water ocean miles below its surface. Just as tantalizing for life is Europa, which may also have a liquid oceans miles below its cracked surface of ice. Though unlikely for life, Io is the most geologically active body in the solar system, and likely the only moon with its own magnetic field. I could wax on and on all day about the sixteen moons that make up the Jovian system, but I’ll spare you.
Here’s the thing; why won’t any of the spacecrafts land on any of these moons?! We have this great opportunity to get right up close to the most interesting and diverse lunar system in the solar system, and we’re stopping short. Don’t get me wrong, I’m ecstatic about the return to Jupiter, but it could be so much more. The other mission under consideration was a return to Saturn, complete with a probe to land on Titan. Why not then land on one of Jupiter’s moons?
Take Mars as a marvelous example. The amount of mapping information gathered by various orbiters was tremendous to be sure, but we actually had to land physical robots on its surface before we had conclusive proof of its watery past.
Jupiter being a gas giant has no actual surface to land on, but the moons are just teeming with potential discoveries. Ideally I would love to see some kind of lander able to drill down through the top sheet of ice on Europa to its sea underneath. Of course the engineering needed to put such an ambitious mission together is probably out of reach right now. Even so, some kind of rover would be a tremendous boon for both science and for the public interest. The rovers Spirit and Opportunity have been public favorites since they first started trundling around Mars’s surface more than five years ago. Another ambitious mission would be just what the agency needs to keep the public interest.