Brussels, 16 Jan 2006
A team of British scientists will be among the first people to examine a tiny quantity of dust collected from the tail of a comet. The capsule which contains the microscopic comet dust landed in a Utah desert in the US at 03:12 local time on 15 January.
The touchdown of the capsule containing the dust, equivalent to a teaspoon-full, is the result of a seven-year, 4.6 billion km round-trip. The other highlight of the trip was the probe's close encounter with comet Wild on 2 January 2004, when the probe came within 149 miles of the comet, sweeping up dust it left in its trail, before beginning the long journey back to earth.
Scientists from the Open University's Planetary and Space Science Research Institute (PSSRI) will be among the first to examine some of the estimated million particles of dust. The excitement over what some might consider as just dust is due to the fact that the comet from which the material was collected is believed to be a refugee from the earliest formation of the solar system. Because the comet is mostly ice, its components will have been unheated, and therefore largely unchanged, since the formation of the sun and planets.
'That time was four-and-a-half thousand billion years ago, back when the Solar System formed; so what we hope to know from these particles is essentially what the Solar System looked like at that time, and essentially what we're all made of,' said Dr Simon Green of the PSSRI.
The interplanetary dust is therefore a way of peering into the distant past and finding out a little more about what made the solar system, and eventually, all life.
The PSSRI team was employed by NASA for four distinct tasks during the mission: The design and provision of sensors for the Dust Flux Monitor instrument, which was used to deflect larger particles and save the precious dust; modelling of the dust 'coma' or trail; and developing methods to extract the dust from Aerogel, which captured the dust. The final, and most important, task is to analyse the dust to determine its component parts, and what this is likely to mean.
The mission blasted-off from Cape Canaveral in Florida on 7 February 1999. The probe containing the capsule made three loops of the Sun before meeting comet Wild (pronounced 'Vilt'). Particles from the comet were caught in a tennis racquet-shaped array filled with Aerogel, the lightest substance created by man. Aerogel is inert and was essential to prevent the particles of dust, which would have been travelling at six times that of a bullet, from heating up on impact. The dust is now embedded in the Aerogel array, chemically unchanged from when it was captured.