NASA’s Genesis mission swings into full gear today as its instruments, three of which were designed and built by the Department of Energy’s Los Alamos National Laboratory, begin capturing particles from the sun.
Genesis, a remote-controlled space mission, went into orbit Nov. 16 around the Lagrange 1, or L1 point, a place nearly one million miles from the Earth toward the sun where the gravities of the Earth and sun are balanced. Genesis will hang out around the L1 point for nearly two and a half years and then return to Earth. During this time, Genesis’ instruments will collect samples of the solar wind to reveal the makeup of the cloud that formed the solar system nearly five billion years ago and will help scientists understand the origin of the solar system.
“When you send up the commands and the instruments come on for the first time in space, you feel like you are out there yourself – it’s really a great feeling,” said Roger Wiens, leader of the Genesis payload team at Los Alamos National Laboratory.
Scientists believe the solar system likely began with a dense cloud of gas and dust that collapsed in on itself. Most of this “solar nebula” condensed to form the sun, while outlying particles coalesced into the diverse planets, moons and comets that make up our solar system.
Although scientists have a general understanding of the formation of the solar system, the composition of the initial nebula remains relatively unknown. Fortunately, nature provides a record of the solar nebula; its pristine composition is preserved for the most part in the outer layers of the sun. The solar wind provides a continuous flow of this material into space.
Genesis’ main goal is to determine isotopic ratios of different elements in solar matter, with a focus on oxygen – an element making up two thirds of everything found on earth. Oxygen isotope ratios vary among the different planets in the solar system, and this puzzles scientists because all solar system bodies were supposedly formed from the same raw materials. An isotope is a variation of an element – it has more or fewer neutrons in its nucleus making it heavier or lighter than the average weight of the element.
Los Alamos designed and built a solar wind concentrator to collect a high concentration of oxygen and return the sample back to Earth for analysis. The concentrator takes solar wind and passes it through a series of electrically charged grids into a bowl-shaped mirror. The mirror reflects a filtered stream of elements heavier than hydrogen upward into a centrally poised collector tile, where oxygen and other elements embed themselves.
“The concentrator is the first solar instrument sent into space that we will ever see again,” said Beth Nordholt, of the Neutron Science and Technology Group and one of the leaders on the concentrator instrument. “All other instruments aboard spacecraft remain in space indefinitely, or, like Lunar Prospector, are intentionally crashed after their mission ends. This is the first mission in three decades, since the Apollo missions in the seventies, that will bring extraterrestrial samples back to Earth for analysis.”
The other two Los Alamos instruments aboard Genesis are solar wind ion and electron monitors. Genesis’ ion and electron monitors instantaneously determine the speed, density, temperature and approximate composition of the solar wind and translate that knowledge into actions for the solar wind concentrator and solar wind collector arrays – five meter-sized panels containing 55 coaster-sized tiles made of a variety of materials selected to trap specific elements in the solar wind.
“The monitors were turned on several months ago in preparation for their role during solar wind collections,” said Wiens. “These instruments communicate with Earth frequently and give a solar wind weather report over the mission’s duration. We have data from the flight to L1 and it has been exciting watching the space weather so far. We’ve had a rather stormy autumn in space, which has been great for checking out our instruments.”
Genesis will collect just 10 to 20 micrograms of solar wind – or the equivalent of a few grains of salt. The extraterrestrial material will return to Earth in 2004 – in the spacecraft’s specially designed sample return capsule – for study by scientists around the world over the next century in search of answers to fundamental questions about the exact composition of the sun and solar system.
Los Alamos National Laboratory is operated by the University of California for the U.S. Department of Energy.
