[AstroNet] Seeing the lunar eclipse from 50 kms away

[Maciej Soltynski]

>From http://www.physorg.com/news/2011-06-lro-extreme-close-up-eclipse.html

 

LRO to take extreme close-up of eclipse

 

Orbiting about 50 kilometres above the lunar surface, NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft will get a "front-row seat" to the total lunar eclipse on June 15, says Noah Petro, Associate Project Scientist for LRO at NASA's Goddard Space Flight Center in Greenbelt, Md. 

 

LRO's Diviner Lunar Radiometer instrument will record how quickly different areas on the moon's day side cool off during the eclipse. Since large boulders cool more slowly than a fine-grained or dusty surface, Diviner will be able to see what areas are covered with boulders and what regions are blanketed by dust. 

 

"This is an unprecedented opportunity to learn more about the uppermost few millimeters of the moon," says Diviner Principal Investigator David Paige of the University of California, Los Angeles. "Diviner plans to operate continuously during the entire eclipse period, targeting ten specific regions. The ten sites represent a diverse selection of lunar terrains. Some consist of fine dust, others are rocky, and there are a variety of compositions including dark, iron-rich lunar maria and light, iron-poor lunar highlands. Diviner will target these features before, during, and after the eclipse, which will allow us to observe how these different surfaces respond to the sudden drop in temperature." 

 

"The moon turns slowly -- a complete day-night cycle lasts more than 29 Earth days," says Petro. "So lunar dusk and dawn last a long time, and normally the lunar surface cools down and heats up slowly. This eclipse is a special opportunity to see what happens if you 'switch off' the sun relatively quickly. It's like taking a pie out of the oven and throwing it into the freezer without letting it cool down first. We want to see how the moon's surface responds to this abrupt temperature change," said Petro. 


 

The Diviner observations will complement surface roughness measurements from LRO's other instruments because Diviner can get hints at what lies just beneath the surface, according to Petro. "LRO's camera and laser altimeter might see a flat, dusty region, but if Diviner sees that it is cooling unusually slowly, that tells us large blocks of material are hidden beneath a thin layer of dust," said Petro. 


 

During the June 2011 lunar eclipse, scientists will be able to get a unique view of the moon. While the sun is blocked by the Earth, LRO's Diviner instrument will take the temperature on the lunar surface. Since different rock sizes cool at different rates, scientists will be able to infer the size and density of rocks on the moon.

 

 The eclipse presents unusual conditions for LRO, according to Petro. LRO runs on solar energy, with battery back-up for power during its approximately hour-long journey over the moon's night side each orbit. LRO's other instruments will be turned off to conserve energy during the long night imposed by the eclipse, and the spacecraft will have to endure a longer period of deep cold. 


 

This will be the first time LRO operates an instrument during a total lunar eclipse, according to Petro, and it will be the longest eclipse during the mission's expected lifetime.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.saasta.ac.za/pipermail/astronet/attachments/20110614/461caf9b/attachment.html>