Tuesday, September 18, 2007


Deirdre Kelleghan September / October 2004 Arcturus

“ Man must rise above the Earth – to the top of the atmosphere and beyond – for only then will he fully understand the world in which he lives”

Socrates, 469 – 399 BC

NASA has a series of ‘Discovery’ probes, they are unmanned and designed to explore our solar system. Genesis, built at a cost of 200 million dollars, is one of these probes.

Inexpensive by NASA standards, the mission of Genesis is to capture retrieve and bring back particles of the solar wind to help explain the origins of our solar system. The solar wind is made up of parts of the solar corona rushing into interplanetary space at supersonic speed.

The Genesis Space Probe

Images Courtesy NASA/JPL- Caltech

The solar wind, blown continuously by the sun passes the Earth at an average speed of 400 kilometers per second and eventually blends with the interstellar medium

beyond the edge of the Solar System.

During its passage it sweeps up evaporated gases from Planets and Comets along with fine particles of meteoritic dust and even cosmic rays of galactic origin. The influence of the solar wind is felt throughout interplanetary space and it provokes in the Earths atmosphere

Polar Aurora and magnetic storms.

In November 2003, when I visited Iceland I witnessed this wonderful phenomenon. The experience of seeing the Aurora Borealis certainly brought home to me the magical movement of colors and the twisting display produced by the interaction of the solar wind and the Earth’s magnetic field. It’s amazing to think that the Genesis Mission will capture pure untainted particles of the solar wind.

The space probe Genesis was launched on August 8 2001 from the Kennedy Space Center, Cape Canaveral, Florida on a Delta 7341 rocket. It left Earth’s atmosphere and traveled out to a point

where gravity from the Earth and Sun are precisely balanced. This point is called the ‘L1 Lagrange Point’ and is clear of the Earth’s magnetosphere. In November 2001 Genesis went into orbit around the L1 point, and not around any object.

The solar wind streams off the Sun in all directions at speeds of 400 km/s (almost 1 million miles per hour). The source of the solar wind is the Sun's hot Corona. The Corona’s temperature

being so high that the

Sun's gravity cannot hold on to it.

The solar wind generated by our nearest star is quite different from the Earth’s surface.

Wind on Earth is created by differences in atmospheric pressures. This ‘wind’ carries about one million tons of hot

Plasma away from the Sun every second – this plasma consists of electrically charged particles with temperatures reaching 100,000 Kelvin’s

While in orbit, the Genesis space probe was bathed by the solar wind that is hurled out from the Sun. These solar wind particles are similar to material from which the planets are formed and include atoms, ions, and high-energy particles.

Once it was in position, the Genesis space probe uncovered its collectors. Particles of solar wind were embedded in the collector arrays, wafer’s made of ultra-pure silicon gold, sapphire and diamond in purest form. The samples of solar wind will be inside a capsule designed to re-enter the Earth’s atmosphere safely. After 884 days collecting solar samples the Sample Return Capsule is re-stowed. The space probe then sets out to return to Earth, just a few hours before re-entry the Sample Return Capsule will be separated from the space probe. This is where the mission takes on a Hollywood movie scenario.

On September 8th 2004, an exciting mid-air recovery of the Sample Return Capsule will take place over the Utah desert. It has a specially designed heat shield to protect it from the 2000oC heat generated during re-entry. Once it has done this, a special parachute will open to slow down the capsule and allow it to slowly glide towards the surface of the Earth. To protect this extra special cargo of sun particles a specially trained crew of military pilots assisted by Hollywood stunt aviators (from the movie industry) will catch the capsule with a specially designed hook. Mission designers do not want the samples to be damaged by a landing on hard ground. This will be achieved when the capsule reaches a sufficiently low altitude - a helicopter will snag the parachute lines before it reaches the ground. The solar wind samples will be stored and cataloged under ultra-pure cleanroom conditions and made available to the world’s scientific community for study. They will be the first samples from space since the Apollo 17 mission when it returned with moon rock in December 1972.

The Genesis space probe itself will head into orbit around the Sun to further investigate this phenomenal star.

The sample particles of the solar wind that Genesis brings back will help scientists to understand the composition of the Sun and the origins of our Solar system.

No comments: