TIM FURNISS / LONDON
The solar wind samples collected on latest Discovery mission will give valuable data on nature of the universe
NASA's Genesis spacecraft is scheduled for launch aboard a Boeing Delta II from Cape Canaveral on 30 July on a mission to capture a small sample of particles from the sun's solar wind.
The $257 million mission, the fifth launch in the Discovery programme, is planned to return a 1.5m (5ft) diameter re-entry capsule to Earth. This will make a parafoil descent over Utah on 8 September, 2004, and be snared in mid-air by a helicopter to protect the fragile samples from being damaged in a ground impact.
The Genesis capsule will return with particles of solar wind equivalent to a small spoon of salt. The solar material will be the first collected extraterrestial samples to arrive on Earth via a spacecraft since December 1972, when Apollo 17 returned with moonrocks weighing 107kg (240lb). Apollo missions 11 to 16, however, also returned with samples of solar wind, collected by an aluminium sheet solar wind collector. These samples contained helium and neon particles.
The Genesis samples - hopefully containing traces of all the natural elements - will be analysed at the former Apollo Lunar Receiving Laboratory in Houston, Texas.
The solar wind is regarded as comprising primordial material from the creation of the sun and could provide valuable data about the nature of the universe.
During the 30-month mission, collector panels inside the capsule will capture solar particles like a flypaper, using wafers made of an ultra-pure material such as sapphire or gold.
Scientists expect 99% of the samples to comprise the hydrogen and helium elements that make up the sun today. Approximately 1% will be a mix of traces of oxygen, nitrogen, neon, argon, xenon and kryptons which were thought to be present in larger quantities when the sun was created inside a nebula of hot dust and gas.
The fourth Discovery spacecraft, Stardust, which was launched in February 1999, will return a capsule to Earth in 2006 carrying dust from the Comet Wild 2 which it will encounter in 2004. It has already collected tiny particles of interstellar dust using a collection medium called aerogel.
Genesis will be followed by three more Discovery mission spacecraft: Contour, the Comet Nucleus Tour; Messenger, a Mercury orbiter; and Deep Impact, a mission to send a projectile into a comet nucleus.
Source: Flight International
