Did scientists make LCROSS seem like a dud by raising expectations of a spectacle?

an adult and two children look at something offscreen while sitting in front of a crowd of people
A crowd gathers to watch LCROSS slam into the Moon on TV.

It was 4:30 on an unseasonably icy October Denver morning. Eighty sleepy but excited visitors gathered at the Denver Museum of Nature & Science, watching NASA TV on a giant screen, and monitoring a live image of the lunar south pole piped in from a rooftop telescope. All eyes were on Cabeus Crater, awaiting the crash of the LCROSS spacecraft. Three separate network news crews were interviewing experts, capturing the ambience, and watching us watch.

The moment of impact approached. The commentators wrapped up their filler, we checked our telescope feed one last time, watched the clock count down to zero…and nothing happened.

The talking heads replayed the footage over and over, trying to find the smallest trace of a flash, a cloud, anything. The mission team quickly reported that it had acquired useful data and that the Lunar Reconnaissance Orbiter had picked up the impact’s thermal pulse. But these notes of success were drowned out in a chorus of groans that turned to mocking laughter. On a live TV news interview, I, along with many others around the world in the same situation, propped up my enthusiasm along with my eyelids and tried to wax eloquent about the unpredictable nature of true exploration.

News anchors and headlines declared “Scientists Excited, But Public Disappointed.” So instead of sharing the excitement of space exploration, this public event seemed to confirm that space scientists are eggheads who fuss over boring things and spend taxpayer money on projects that seemingly provide no bang for the bucks.

Impact cratering is the solar system’s most ubiquitous and primeval geologic process. Every cratered surface tells stories of bombardment and subsequent geologic or atmospheric events. But the crucial science of observing a crater and deducing the nature of the impactor that caused it is still more guesswork than we’d like to admit. The 2005 crash of the Deep Impact probe with Comet 9P/Tempel 1 produced a much bigger dust cloud than predicted, completely obscuring the new crater. The surprisingly gentle LCROSS impact diverged from expectations in the opposite direction. Though this was briefly disappointing and slightly embarrassing, it gives us useful data, helping calibrate our knowledge of impact cratering. Scientifically, the explosion’s uncertain magnitude was just a sideshow to the search for water ice in the cold, permanently shadowed craters near the Moon’s poles (see page 28). 

Did we blow it by raising expectations? I’m afraid we did. I wish we had emphasized the beguiling approach images, along with the expected harvest of meaningful data. Centering our public outreach efforts around the potentially flashy moment of impact was a gamble, a miscalculation. In retrospect, it seems we bought our own hype about, and hopes for, seeing the crash.

We long to see ourselves out there, catching faint hints of our destiny as a spacefaring species. Watching our own crater form on the Moon would be a thrilling confirmation of human hands scratching at the heavens. And, let’s face it, dead, dry worlds are not as compelling as wet and vibrant ones. As we explore planets, we are most excited by signs of water and signs of change. We thought we might provoke the Moon to reveal both in one explosive moment. Though it looked as though nothing changed at the moment of impact, this is wrong. The discovery of water on the Moon changes us, illuminating the original delivery of life’s materials to Earth from space, and bringing us closer to the day we’ll move back out there.

This article originally appeared in print in the February 2010 issue of Sky & Telescope. Subscribe to Sky & Telescope.


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