Mullard Space Science Laboratory

P R E S S  R E L E A S E
05 July 2005
REF: DI050705

UPDATE - Deep Impact mission: Surrey Scientists to supply NASA with images

This week saw the occurrence of one of the most dare-devil space science missions ever. NASA sent a guided copper bullet the size of a washing machine on a collision course with a comet to try and understand the origins of the Sun, the planets and even human beings. Surrey scientists observed the event and have supplied NASA with crucial images.

The mission was called Deep Impact and its aim was to form a crater in the side of comet Tempel 1. Comets are dirty snowballs that inhabit the Solar System and are the debris left over from its formation 4,500 million years ago. Under their surface though, comets harbour untouched material from that early time which means they are like an ancient time capsule.

Tempel 1 is thought to be 9 miles wide but until now that was almost all that was known about it. The impact caused a huge plume of ice and dust to be expelled from the comet, larger than expected. This may indicate a solid but fragile crust, and a hard, but somewhat porous, interior - but analysis over the next days and weeks will tell more about the strength of the comet, what it is made of and the size of the crater.

Scientists at UCL's Mullard Space Science Laboratory near Dorking have been studying comets for many years and Deep Impact provided them with the first opportunity to study their interior structure and composition.

Dr Andrew Coates, head of the Planetary Science Group, said, "Normally we can only observe the outside surface of comets and the gases that they give off when they approach the Sun and heat up. This is the first time that we have been able to glimpse the pristine material under the comet's crust. It has been absolutely amazing."

Dr Coates used the Isaac Newton Telescope on La Palma to study the material ejected from the comet on impact. He says 'We saw a significant increase in the comet's activity after the impactor struck, and a dramatic increase in jet activity from the comet'. He also used the UK Schmidt telescope in Australia to look at the colours of light from the impact, this will give clues on the composition of the pristine material from the birth of the Solar System.

As well as using ground based telescopes, MSSL used a satellite normally reserved for studying the biggest explosions in the Universe, the Swift Satellite.

Prof. Keith Mason, director of MSSL used Swift to watch the event in optical, ultraviolet and X-ray wavelengths. An increase in activity was seen in the ultraviolet, consistent with impacting a hard surface.

Prof. Mason said, "MSSL designed and built an instrument on Swift which is normally used to study how black holes form. It has been great to be able to use it in this event to further our understanding of how the Solar System formed. The telescope observed a significant increase in activity as the impact occurred but this isn't the end of the story. We will continue to watch the comet over the coming weeks as important changes will still take place."



All our images will be available from the MSSL website:


1. Isaac Newton Telescope in La Palma

Images taken by this telescope will allow the study of changes to the tail of comet Tempel 1. The impact should release material which will form bright condensations in the comet's tail. These condensations are then 'blown' down the tail due to the solar wind, giving us the speed of the solar wind. The comet is then acting as a solar wind probe, or a very large wind sock!

2.5 days later the Earth will be located in the same region of solar wind as the comet was and we can take another measurement of the wind speed.

INT gives us the broad picture of the impact event.

2. UK schmidt telescope

UK schmidt gives us a more detailed view with spectroscopic studies. We will be looking at how the amount of carbon monoxide ions and water ions change due to the impact. This will give information on what the comet is made of.

Overall, we will learn about composition of the comet and its structure and strength. Very important for the European Space Agency's Rosetta mission which will land on a comet.

3. Swift satellite

The observations planned with Swift will involve both the Ultra-Violet and Optical Telescope and the X-ray Telescope. The UVOT will look for changes in the Coma, while the XRT will search for changes in the X-ray emission caused by extra material being ejected and interacting with the Solar Wind. There may be an X-ray 'flash' as a result of the impact.

Also, the impact may result in a comet outburst. An outburst has never been observed before and if it happens in the Deep Impact event it will not only be the first one observed but will be observed across the spectrum.

4. Images of the Deep Impact encounter are available from:

5. Artist's Concept images of Deep Impact spacecraft available from:

6. See also the NASA Deep Impact site:

Notes to Editors:

Mullard Space Science Laboratory, UCL

MSSL is situated in Holmbury St Mary between Dorking and Guildford, and is the Space and Climate Physics Department of University College London. The Group moved from London to Holmbury St Mary in 1965 after Holmbury House was purchased with funds donated by the Mullard electronics company. 150 scientists work at MSSL across 5 groups; solar and stellar physics, planetary and plasma physics, astrophysics, detector physics and climate physics. The laboratory houses world-class facilities to design, build and test instrumentation as well as analyse the data taken by the instruments in space.

Contacts at MSSL

Mullard Space Science Laboratory
University College London
Department of Space & Climate Physics
Holmbury St. Mary, Dorking
Surrey, RH5 6NT

MSSL switchboard 01483 204100
MSSL website

Dr. Graziella Branduardi-Raymont
Dr. Alex Blustin
Dr. Andrew Coates
Dr Lucie Green