A week after smashing two probes into the moon, NASA says early data returns are tantalizing and even reveal traces of an impact plume. A worldwide audience was disappointed when the Oct. 9 bombing of the moon failed to produce what NASA had said would be a 6-mile-high plume of dirt and debris.
NASA is calling last week's bombing of the moon a smashing success with the
two probes that smacked into the lunar surface Oct. 9 returning tantalizing
data, including faint traces of an impact plume. NASA has said it ultimately
hopes the probes will yield data about the possibility of water on the moon.
NASA launched an Atlas V rocket to the moon June 18 with two satellites
riding on top: the LRO (Lunar Reconnaissance Orbiter) and the LCROSS (Lunar
Crater Observation and Sensing Satellite). The LRO is in orbit 31 miles above
the moon's surface, mapping the moon in high resolution for future landing
sites and gathering crucial data on the lunar environment that will help
astronauts prepare for long-duration lunar expeditions.
NASA
dropped the LCROSS with the empty 2.5 ton Centaur upper stage of the Atlas
rocket still attached out of orbit late Oct. 8 and begin angling for the lunar
surface. The Centaur hit the surface first, closely followed by the LCROSS.
What
was puzzling, though, was the apparent
lack of
a debris plume from the twin impacts. NASA had predicted that a 6-mile-high
plume of dirt and dust would be created by the impact. But the lack of a plume
disappointed a worldwide audience watching on NASA TV and the Internet. NASA's
live feed tracked the rapidly descending LCROSS to just before impact and
nothing more. The live feed turned to static. Reports from virtually every
available Earth- and space-based telescope failed to show either an impact
flash or a plume.
But
a week later, Anthony Colaprete, LCROSS principal investigator and project
scientist, said in an Oct. 16 statement: "There is a clear indication of a
plume of vapor and fine debris. Within the range of model predictions we made,
the ejecta brightness appears to be at the low end of our predictions and this
may be a clue to the properties of the material the Centaur impacted."
Colaprete
also said, "We are blown away by the data returned. The team is working
hard on the analysis and the data appear to be of very high quality."
NASA
said in the statement:
"The magnitude, form and visibility of
the debris plume add additional information about the concentrations and state
of the material at the [Cabeus crater] impact site.
"The LCROSS spacecraft also captured
the Centaur impact flash in both mid-infrared (MIR) thermal cameras over a couple of seconds. The
temperature of the flash provides valuable information about the composition of
the material at the impact site. LCROSS also captured emissions and absorption
spectra across the flash using an ultraviolet/visible spectrometer. Different
materials release or absorb energy at specific wavelengths that are measurable
by the spectrometers."
"The
images of the floor of Cabeus are exciting," Colaprete said. "Being
able to image the Centaur crater helps us reconstruct the impact process, which
in turn helps us understand the observations of the flash and ejecta
plume."
NASA
also posted some initial images of the impacts on the
LCROSS site.
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