[meteorite-list] Deep Impact Zooms by Earth on New Year's Eve

[Ron Baalke]

December 31, 2007

Media Contact:
Lee Tune
240-328-4914
ltune at umd.edu

Deep Impact Zooms by Earth on New Year's Eve
(Earth Flyby and Moon Pics Mark Start of New Mission)

College Park, Md. -- This New Year's Eve the University of Maryland-led Deep 
Impact team will again celebrate a holiday in a way that few can match, when 
their Deep Impact spacecraft "buzzes” the Earth on a flyby that marks the 
beginning of a more than two-and-a-half-year journey to comet Hartley 2.

In 2005, the Deep Impact team, led by University of Maryland astronomer 
Michael A'Hearn, celebrated July 4th by smashing a probe into comet Tempel 1 
to give the world its first look inside a comet.

The trip to Hartley 2 is one part of a new two-part mission for the team and 
its Deep Impact spacecraft. During the first six months of the journey, the 
Extrasolar Planet Observations and Characterization (EPOCh) mission team 
will use the larger of the two telescopes on the Deep Impact spacecraft to 
search for Earth-sized planets around five stars selected as likely 
candidates for such planets. Upon arriving at the comet the Deep Impact 
eXtended Investigation (DIXI) will conduct an extended flyby of Hartley 2 
using all three of the spacecraft's instruments (two telescopes with digital 
color cameras and an infrared spectrometer. The name for the new combined 
mission, EPOXI, is a combination of the names of its component missions 
(EPOCh + DIXI = EPOXI).

The team is using the flyby of Earth to calibrate the spacecrafts 
instruments for the new mission and to help slingshot it on the way toward 
Hartley 2. Although the spacecraft will come closest to the Earth on New 
Year's Eve, the Maryland-led team has already begun its calibration work.

"On Saturday, 29 December, two days before its close flyby of Earth, the 
Deep Impact flyby spacecraft made observations of the moon to calibrate its 
instruments for its new mission, EPOXI,” said A'Hearn. "Some calibrations 
are obtainable only on a bright, large source, like the moon when reasonably 
close to it. It looks as though everything operated just as the science team 
asked it to operate and you can't ask for anything better than that,” he 
said. "

'This Earth gravity assist provided a unique opportunity for us to calibrate 
our instruments using the Moon,” said Jessica Sunshine, a senior research 
scientist at the University of Maryland. "In particular, the Moon is very 
useful because it fills the entire field of view of the infrared 
spectrometer. The results show that our spacecraft pointing and commanding 
was spot on. We also made measurements which will allow us to 
cross-calibrate our instruments with telescopic data and, in the very near 
future, with a wealth of lunar measurements from new orbiting spacecraft. 
These data will significantly
improve the science from EPOCh observations of Earth and the DIXI flyby of
comet Hartley 2, as well as from Deep Impact's prime mission to comet Tempel 
1," said Sunshine who is deputy principal investigator on DIXI.

Past releases with more information about the mission can be found on the 
University of Maryland's Newsdesk Web site: 
http://www.newsdesk.umd.edu/scitech/release.cfm?ArticleID=1564
To see all UM Deep Impact releases search for Deep Impact using the search 
box in the upper right portion of the page.

Images of the moon taken by the Deep Impact spacecraft and updates about the 
mission can be seen on the web site for the new EPOXI mission: 
http://epoxi.umd.edu/

The DeepImpact Web site is: http://deepimpact.umd.edu/

For people in the United States, the Deep Impact spacecraft generally will 
be below the horizon during the nighttime hours on New Years Eve and New 
Year's day and thus not visible, but check the EPOXI site for detailed 
viewing information.