[meteorite-list] XMM-Newton to Observe Deep Impact

[Ron Baalke]

http://www.esa.int/SPECIALS/Rosetta/SEMSZC2DU8E_0.html

XMM-Newton to observe Deep Impact
European Space Agency 
23 June 2005

ESA's orbiting X-ray observatory XMM-Newton joins the fleet of
spacecraft taking part in one of the world's largest astronomical
observation campaigns - the Deep Impact event - on 4 July 2005.
 
On 4 July, NASA's Deep Impact mission will send a 370 kg copper
projectile ('impactor') to impact on Comet 9P/Tempel 1, to dig into the
secrets of its nucleus.

Comets are very interesting celestial objects. In fact, their
composition carries important information about the origin of the Solar
System, as they have remained virtually unchanged since then.

X-ray observations obtained by chance during a natural outburst from
Comet Hale-Bopp showed a strong increase in X-ray intensity related to
the dust-rich cloud that emerged on that event.

It was decided to commission ESA's XMM-Newton X-ray observatory, one of
the biggest science satellites ever built in Europe, to make X-ray
spectroscopic measurements of this upcoming impact, and contribute to
the rare knowledge about the properties of comets.

Spectroscopy - the spreading of light into a spectrum - is at the heart
of the XMM-Newton observations and allows astronomers to measure a
source's composition.

In the same way the colour of a lamp indicates what gas is used in
street lighting, the three scientific instruments on board XMM-Newton
will reveal the deepest secrets of this comet, including its chemical
composition and temperature.

Because the interior of a comet nucleus has been much less modified by
solar radiation and cosmic rays, it is believed to be different from the
surface crust and the material that sublimates there to form the comet
tail. As a result of the impact, it is expected that a vast amount of
this material will be released from the interior into space.

This induced outburst of the comet's nucleus and the expected X-ray
emission will be observed by XMM-Newton's three instruments. The X-ray
spectrometer (RGS), the three X-ray cameras (EPIC) and its optical and
ultraviolet monitor (OM) will collect information about the comet's
materials that is not usually accessible to observations.

All instruments used will operate simultaneously for a total of just
over 24 hours. It is planned to observe for about 6 hours before the
event and for 18 hours after it, which will allow XMM-Newton to observe
changes in the composition of the ejected material.

XMM-Newton will transmit the obtained data continuously to the European
Space Astronomy Centre (ESAC) in Spain, via ESA's mission control centre
at the European Space Operations Centre (ESOC), Darmstadt, Germany.

The raw scientific data are monitored in real time by the XMM-Newton
team at ESAC. Generally data processing is done in two steps: generation
of data files at ESAC within 10 days and, after the observations,
generation of "pipe-line" products at the Survey Science Centre,
Leicester, UK. But data of "moving" objects, like this comet
observation, require special processing that is done by the XMM-Newton
team after the generation of the data files.

When not observing Comet Tempel 1, XMM-Newton's actual mission is to
help solve many cosmic mysteries of the violent Universe, from what
happens in and around black holes to the formation of galaxies in the
early Universe. XMM-Newton has detected more X-ray sources than any
previous satellite.

Its telescope mirrors are some of the most optically efficient ever
developed and, with its highly sensitive detectors, XMM-Newton sees much
more than any previous X-ray satellite. XMM-Newton's high-technology
design uses over 170 wafer-thin cylindrical mirrors spread over three
telescopes.

Its orbit takes it almost a third of the way to the Moon, so that
astronomers can enjoy long, uninterrupted views of celestial objects.

 
For more information:
 
Norbert Schartel, ESA XMM-Newton Project Scientist
E-mail: norbert.schartel @ sciops.esa.int

Rita Schulz, ESA BepiColombo Project Scientist
E-mail: rita.schulz @ esa.int