NASA’s Big Hit: LCROSS Impacts Moon

Geek Culture

Closeup Lunar Image from LCROSS (Image From NASA)Closeup Lunar Image from LCROSS (Image From NASA)

Closeup lunar image from LCROSS (Image From NASA)

LCROSS looked a whole lot more like a whimper than a bang, falling far short of the dramatic NASA animation endlessly played on TV to stoke interest in the moon mission. But fear not: The angels are in the details, and they are yet to be revealed.

You would not have noticed if you were watching it on TV, but LCROSS did successfully impact on the lunar South Pole this morning in the crater Cabeus. The mission actually had two impacts: The first was a spent Centaur upper stage that had been ferried to the impact trajectory along with the LCROSS spacecraft. The second impact was the LCROSS spacecraft itself.

The goal of this dual impact was to have the Centaur upper stage impact first, allowing the LCROSS spacecraft to observe close-up the results of the impact. In fairness, the view from LCROSS as it approached the moon was amazing — even though there was no obvious visual evidence of impact, which early data from the infrared camera on the craft indicates did occur.

What happens next is a whole lot of math and science. The LCROSS spacecraft included nine individual science instruments. This suite of instruments consisted of one visible camera, two near-infrared cameras, two mid-infrared cameras, a visible light spectrometer, two near-infrared spectrometers, and a photometer. All nine of those instruments were gathering data simultaneously and streaming that data back to Earth. That is a lot of information.

All of that recorded data is being captured and distributed to the appropriate science team members. At the same time, the data from the Lunar Reconnaissance Orbiter (LRO), which also recorded the impact, will be down-linked for review; the data from the Hubble Space Telescope observations will be down-linked and analyzed; data from numerous ground based telescopes will be distributed and analyzed. This is where the discoveries happen. It’s science!

First, all of that data has to be reduced. The raw data is sometimes almost impossible to understand, but as multiple pieces of data are put together and combined with previously captured calibration data, the noise from the data can be removed and the signal that contains the science can be distinguished. There are whole groups of scientists and engineers who are experts at this kind of work.

Once the data is cleaned up, scientists can begin to look at what the data means individually. What did the cameras on LCROSS capture? What emission and absorption lines were seen by the spectrometers? How bright was the moment of impact as captured by the photometer? At the same time, the individual observations from the instruments on Hubble, LRO, and other observations will be analyzed for their own, individual data.

Finally, the data will be looked at as a whole.

  • What was the infrared camera on LCROSS seeing while the Hubble Wide Field Camera 3 observed the same thing in the visible part of the spectrum?
  • Immediately after the impact, the spectrometer on LCROSS recorded the plume spectrum. What did the Space Telescope Imaging Spectrograph on Hubble record in the time afterwards?
  • How do the closeups from LRO compare with the closeups from LCROSS?

Putting all of the data together creates an intricate picture of the events.

Some of the data from these various levels of analysis will be available quickly, other data will take time. This is where the rubber meets the road in science and engineering, as all of the engineering work that went into building the spacecraft and instruments enables the science to follow.

Congratulations to the entire LCROSS team!

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