It’s been some time since we checked in with the Dawn spacecraft whose mission it is to orbit and explore two dwarf planets in our solar system – Vesta and Ceres.
Dawn arrived at Vesta in July of last year and since then it has been orbiting the giant asteroid, studying its gravity field and material composition, topology and history. We got some jaw-dropping photographs out of this first stop. Before Dawn we only knew Vesta as a small fuzzy dot even with the best telescopes.
Both Vesta and Ceres make their home in the asteroid belt – a large donut-shaped debris field between the orbits of Mars and Jupiter. We have known of those dwarf planets (there are a few more) since the early 1800s, but they’re in a place in our solar system that doesn’t allow for convenient observation. The only way to learn more about them was to boldly go there.
Enter Dawn, with its awesome ion propulsion, which we explored in an earlier issue of this column. It took it a while to get there but the new technology functioned perfectly. Ion propulsion is one of those “barely there” methods of movement, but since it is absolutely constant it can build up to mindboggling speeds over time.
Going to an asteroid requires a tremendous amount of fuel and patience, so the Dawn systems were a perfect match, because the ion engine literally sips fuel with super-efficiency.
Dawn discovered that Vesta is a scarred, pockmarked world with a surface tortured by impact events for the past 2 billion years. It is one of those rare leftovers from the beginning of the solar system, a giant rock that didn’t quite make it to the designation of a planet (yes, yes – we see you, over there, little Pluto… you have lots of company since your unfortunate demotion!).
Vesta is around 300 miles across. Ceres, Dawn next target, is almost twice that. It took Dawn a little while to cut the cord, as it were, because it had trouble with one of its reactions wheels. Loyal readers will groan in vexation at this point (all together now: “Oh no, not another reaction wheel!”). But the engineers can use small thrusters to keep Dawn oriented properly while they check out the reaction wheel issue en route to Ceres while the spacecraft is just merrily cruising along.
So why are asteroids so cool these days? Big lumps of rock somewhere out there, what’s up with that? We’re still a long way away from it, but asteroids could turn out to be prime real estate for materials mining. One could conceivably send robotic missions there to mine the asteroid for minerals and ore, process them and use the resulting materials for colonies elsewhere, or to build new spacecraft, without taxing Earth’s rapidly depleting natural resources any more.
We’ll keep checking in with Dawn as it travels towards Ceres. Meanwhile, we’ve got some awesome pictures of an alien world to drool over.
Check them out at http://dawn.jpl.nasa.gov/
Beate Czogalla is the professor of theater design in the Department of Theatre and Dance at Georgia College & State University. She has had a lifelong interest in space exploration and has been a solar system ambassador for the Jet Propulsion Laboratory/NASA for many years. She can be reached at firstname.lastname@example.org.