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TOPIC: Deep Impact
Blobrana


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RE: Deep Impact
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As the spacecraft for the EPOXI mission flew past the Earth and moon during the last weekend of 2007, it had some chores to do. One was to do a lunar calibration of the instruments.

HRI image of moon from 2007 lunar cal
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Credit: NASA/JPL-Caltech/UMD/GSFC

This white-light image of the Moon was taken by the NASA EPOXI mission as part of the Earth-Moon Flyby calibration of the instruments. The image was taken by the High Resolution Instrument (HRI) visual imaging camera at 22:00 UT on 29 Dec 2007, when the spacecraft was at about three times the Earth's distance from the Moon. To compensate for the defocus of the HRI telescope, the calibrated image was post-processed using 20 iterations of a modified Lucy-Richardson deconvolution procedure that includes wavelet noise dampening. The overly bright limb of the moon is the most noticeable artifact of the deconvolution.

quicklook HRI IR results, slide 1 flatfield

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This image does not appear to be all that exciting or beautiful, but is the critical measurement made during the 2007 Earth Flyby. NASA blurred the Moon at three different rates and then stitched the results together to make a "flat-field" -- a record of the instrument response to a uniform light source.

quicklook HRI IR results, slide 2

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quicklook HRI IR results, slide 3

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Credit: NASA/JPL-Caltech/UMD/GSFC

These two images show the IR data reconstructed as images of the Moon at 1.5µm. These are very comparable to the VIS images (same resolution as MRI). The longer wavelength thermal IR was as we expected mostly saturated except at the shortest exposures (the little image "1005000").

The December 2007 Earth gravity assist provided a unique opportunity for scientists to calibrate their instruments using the Moon. In particular, the Moon is very useful because it fills the entire field of view of the spectrometer. As planned, mission controllers smeared their exposures while scanning across the Moon. The results show that their spacecraft pointing and commanding was spot on. For the first time, either on the ground or in space, NASA now have uniform data at all wavelengths covering over 90% of the IR detector. Flight controllers also made measurements which will allow NASA to cross-calibrate their 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.

Source NASA



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Blobrana


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NASA's comet-busting spacecraft is on its way to rendezvous with another comet in an extended mission that will also hunt for Earth-sized planets around a cluster of stars. The Deep Impact probe zipped past Earth Monday, the first of three flybys designed to use the planet's gravity to hurtle the spacecraft toward comet Hartley 2 for a 2010 meeting.

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Blobrana


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The Deep Impact probe zipped past Earth Monday, the first of three flybys designed to use the planet's gravity to hurtle the spacecraft toward comet Hartley 2 for a 2010 meeting.

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Blobrana


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Deep Impact Probe Makes Flyby Of Earth
NASA's Deep Impact space probe is making a New Year's Eve flyby of Earth on its way to comet Hartley 2.

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Blobrana


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EPOXI mission Earth Flyby
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After its encounter with Tempel 1, the Deep Impact spacecraft, now being used for the EPOXI mission, continued in its orbit around the sun that would bring it past Earth late this year. Along the way, there have been some trajectory correction manoeuvres (TCMs) to adjust the spacecraft's path so that after the flyby it will be in an orbit (white circles) that will intersect with comet Hartley 2 in 2010. During the flyby, the spacecraft will experience a gravity assist from Earth that will steal some of the orbital energy from the spacecraft, changing its orbit from the yellow path to the white one. Additional Earth flybys in 2008 and 2009 will refine the orbit even further.

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Blobrana


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RE: Deep Impact
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NASA has selected a pair of celestial targets for the Deep Impact spacecraft that blasted the comet Tempel-1 with a copper projectile on July 4, 2005.
Under the Extrasolar Planet Observation and Characterization and Deep Impact Extended Investigation (Epoxi) mission, the Ball Aerospace mothership will use the larger of its two telescopes next month to examine planetary systems that have been discovered around other stars, and then conduct a close flyby of the comet Hartley 2 on Oct. 11, 2011.

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Blobrana


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The Deep Impact spacecraft, which thrilled millions of armchair astronomers in 2005, when it sent a large metal impactor crashing into a comet nucleus, will be redirected to study a second comet, Hartley 2, NASA announced today. The new mission is named EPOXI.
The decision was made after an international consortium of astronomers led by the University of Hawaii's Dr. Karen Meech, a co-investigator on the mission, announced that the first-choice target, called comet 85P/Boethin, has apparently disappeared.

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Blobrana


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85P/Boethin
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University of Hawaii astronomers and colleagues from around the world have searched in vain for a missing comet that was supposed to appear by October.
The cosmic mystery forced the rescheduling of NASA's Extrasolar Planet Observation and Deep Impact mission to the comet 85P/Boethin. The EPOXI mission will now go to a different comet.

"We were astonished when it wasn't there" - UH astronomer Karen Meech, who led the effort to try to find Boethin.

The Subaru 9-meter telescope and 3.6-meter Canada-France-Hawaii Telescope on Mauna Kea, both with sensitive wide-field cameras, joined observatories worldwide in the futile hunt for 1-mile-long, half-mile-wide Boethin.

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Blobrana


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RE: Deep Impact
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Ephemerides
Date       UT      R.A. (J2000) Decl.  Elong.  V        Motion      Distance
            h m                                      "/min   P.A.       km
2007 12 15 0000   02 00 35.7 +05 21 57 127.2          0.29  236.8    5125425
2007 12 16 0000   02 00 14.2 +05 18 18 126.0          0.25  234.3    4829254
2007 12 17 0000   01 59 56.3 +05 14 54 124.9          0.22  230.4    4532934
2007 12 18 0000   01 59 42.2 +05 11 42 123.9          0.18  224.2    4236313
2007 12 19 0000   01 59 32.2 +05 08 41 122.8          0.15  213.8    3939255
2007 12 20 0000   01 59 26.5 +05 05 47 121.7          0.12  196.8    3641644
2007 12 21 0000   01 59 25.5 +05 02 59 120.7          0.12  172.6    3343383
2007 12 22 0000   01 59 29.6 +05 00 09 119.7          0.14  148.9    3044399
2007 12 23 0000   01 59 39.6 +04 57 13 118.7          0.19  132.5    2744635
2007 12 24 0000   01 59 56.7 +04 54 01 117.7          0.26  122.8    2444044
2007 12 25 0000   02 00 22.7 +04 50 20 116.8          0.37  117.2    2142575
2007 12 26 0000   02 01 01.0 +04 45 50 115.9          0.52  113.8    1840148
2007 12 27 0000   02 01 57.7 +04 39 57 115.1          0.77  111.7    1536613
2007 12 28 0000   02 03 25.5 +04 31 32 114.4          1.23  110.5    1231675
2007 12 29 0000   02 05 54.2 +04 17 56 113.8          2.20  109.9     924720
2007 12 30 0000   02 10 54.3 +03 51 06 113.8          5.00  109.6     614301
2007 12 31 0000   02 26 29.5 +02 27 43 115.8         21.56  109.7     295774
2008 01 01 0000   16 55 39.5 +10 21 51  42.5         277.1  073.0      82510
2008 01 02 0000   18 19 29.1 +15 44 39  39.3         10.85  077.9     417161
2008 01 03 0000   18 29 33.9 +16 14 20  39.5          3.55  079.2     731405
2008 01 04 0000   18 33 40.4 +16 24 56  39.6          1.77  080.8    1040087
2008 01 05 0000   18 35 56.7 +16 29 38  39.7          1.07  083.2    1346172
2008 01 06 0000   18 37 24.6 +16 31 32  39.7          0.73  086.9    1650825
2008 01 07 0000   18 38 26.6 +16 31 45  39.7          0.53  091.9    1954645


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Blobrana


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EPOXI mission
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NASA has given a University of Maryland-led team of scientists the green light to fly the Deep Impact spacecraft to Comet Hartley 2 on a two-part extended mission known as EPOXI. The spacecraft will fly by Earth on New Year's Eve at the beginning of a more than two-and-a-half-year journey to Hartley 2.
The EPOXI mission is actually two new missions in one. During the first six months of the journey to Hartley 2, the Extrasolar Planet Observations and Characterisation (EPOCh) mission 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 colour cameras and an infrared spectrometer).

"It's exciting that we can send the Deep Impact spacecraft on a new mission that combines two totally independent science investigations, both of which can help us better understand how solar systems form and evolve" - Deep Impact leader and University of Maryland astronomer Michael A'Hearn, who is principal investigator (PI) for both the overall EPOXI mission and its DIXI component.

The EPOXI mission brings back the Deep Impact partnership between the University of Maryland, NASA's Jet Propulsion Laboratory (JPL) and Ball Aerospace & Technologies Corporation, and adds NASA's Goddard Space Flight Centre.
When the Deep Impact/EPOXI spacecraft passes by Earth on December 31, 2007, it will use the pull of our planet's gravity to direct and speed itself toward comet Hartley 2. In doing this the spacecraft is aimed toward an encounter with comet Hartley 2 at a time when tracking stations in two different locations on Earth can "see" the spacecraft to receive data from it and send commands to it. In late December 2007, the spacecraft's instruments will be recalibrated using the Moon as a target.
Hartley 2 was not the original destination of the new mission. It was selected in October following the surprising realisation that despite tremendous efforts by many observatories and observers, the scientists could not reliably identify their first choice, comet Boethin, and its orbit in time to plan the mission flyby of Earth. The team then recommended to NASA that it be allowed to fly to the backup target, comet Hartley 2.

"Hartley 2 is scientifically just as interesting as comet Boethin since both have relatively small, active nuclei. As we have worked the details of the comet Hartley 2 encounter, we are confident that the observations will turn out to be even better than Boethin" - Michael A'Hearn.

In June of 2008, the extended mission will end its EPOCh portion and transition to a long, quiet journey to comet Hartley 2. The total trip -- measured from its December 31, 2007 flyby of Earth to its closest encounter with the comet on October 11, 2010 -- will be roughly 1.6 billion miles or some 18 times the distance from the Earth to the sun. It will take the spacecraft three trips around the sun before it can intercept the comet, which at that time will be at a distance of some 12.4 million miles from Earth.

At the nearest point of its flyby of Hartley 2, the spacecraft will be some 550 miles from the comet. Deep Impact does not have another probe, so Hartley 2 will not get hit, but the close-up view will allow the spacecraft's two telescopes to closely observe surface features of the comet while its infrared spectrometer maps the composition of any outbursts of gas from the surface.

Comet science goals for this phase of the mission are to:
a) Search for and, if found, produce maps of outbursts of gas from the surface of comet Hartley 2. Track the outburst as the comet rotates. Correlate outbursts with surface features. Such outbursts were observed during the spacecraft's flyby of comet Tempel 1.
b) Obtain infrared spectral maps of gasses in the innermost portion of the coma. The coma is the cloud of gas and dust that surrounds the comet. Investigate the distribution of dust and gas in the coma.
c) Search for frozen volatiles on the surface of the comet. Water ice, for example, was discovered when the flyby explored Tempel 1.
d) Produce broad band images of the comet that will establish limits on the size of the nucleus. Produce a model of its shape.
e) Map the brightness and colour variations of the surface. Locate landscape features that indicate the processes by which the comet was formed. Compare the distribution of crater sizes with the distribution of the size of craters on other comets, asteroids and planetary satellites.
f) Map the temperature of the surface to assess how readily heat is transmitted to the interior and the flow of subsurface volatiles, such as water vapour, to the surface.

Source: University of Maryland

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