Beate Czogalla
Shortly after 7:30 a.m. last Friday, the Moon got two brand-new craters to add to its vast collection of impact sites. There’s something different about the two new kids on the rock block, though. Unlike most of the Moon’s other craters, these two were not carved out by some random meteorite but are in fact man-made.
Following the final minutes of the LCROSS spacecraft and its Centaur upper stage, I, along with millions of other space exploration fans, held my breath as the two long distance travelers approached the lunar surface.
The night before, the Moon, as observed by the LCROSS spacecraft, looked more or less the same minute to minute. Some major excitement occurred around 9:52 p.m. Thursday when the Centaur upper stage separated from the actual spacecraft, which then swung around to point its cameras at the rapidly receding empty rocket shell. “Receding” is a relative term here, of course, as both objects were still on the same path heading for a lunar impact.
But for LCROSS to be able to observe the impact of the Centaur, it needed the rocket hull to get there first. So that’s why the two pulled apart and LCROSS even stepped on the brakes for a little while, allowing the Centaur to get a good head start of about four minutes.
That night the Centaur headed straight for Cabeus crater at the Moon’s south pole with the LCROSS spacecraft in hot pursuit. Cabeus contains areas where the sun never shines — due to its location near the pole the sunlight comes in at such a shallow angle that some places literally never see the light of day. Over the course of millions of years, comet debris and other icy particles may have collected in these shadowy areas and just simply accumulated over time because there’s no sunlight to melt it.
Ultimately, this was the goal of the entire LCROSS mission: smash something into one of those permanently shadowed areas, watch the debris plume and analyze it for traces of water vapor — a sure-fire sign that water ice does exist on the Moon.
So there I was, my eyes glued to the screen, as the Moon’s surface got closer by the second, captured in frightening detail by the LCROSS cameras, enough to give you a sense of vertigo and half-way expecting a big bonk on the head. The comment came through that the Centaur had impacted the Moon exactly as planned — but no matter how hard I looked I could not see a thing.
Having seen some of the artists’ renditions of what the impact might look like I had expected a bright flash of light, a brief inferno, and a debris cloud, but instead I saw exactly nothing. Four minutes later all telemetry data with the LCROSS spacecraft was lost, indicating that it, too, had hit the Moon to find its demise in Cabeus crater.
Presumably there was a lot of perplexed head-scratching going on around the world by people like me who had hoped for a bit of a light show. Still, the mission scientists were ecstatic, having gathered a mother lode of data during the four crucial minutes between the impacts.
While the average Joe like me may not have seen anything, the instruments on board the spacecraft were a lot closer to the action and had many more ways of observing the crash. Other major telescopes around the world had tuned in for the spectacle, and as I am writing this they’re all still busy analyzing their observation results — even Hubble is involved.
It may be a few days yet before we get any new information, and perhaps the final answer to the question of whether there is water ice on the Moon.
It ain’t over ‘till it’s over, as they say, and while I didn’t see a thing, I look very much forward to learning what our remote eyes on the spacecraft saw. Many people put a lot of work into this ingenious mission and they’ll let us know what they found out.
Meanwhile, the sister mission to LCROSS, the Lunar Reconnaissance Orbiter, is chugging along in orbit around the Moon, providing us with daily new stunning views. These days, Moon aficionados never have to be without their thrills.
Beate Czogalla is the associate professor of theater design in the Department of Music and Theater 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 our_space2@yahoo.com
