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Los Alamos to ride on NASA mission to collect solar material

LOS ALAMOS, N.M., Oct. 27, 1997 -- Los Alamos National Laboratory scientists will provide three key instruments for a mission that will spend two years in space collecting material that blows off the sun, then return to Earth where the captured solar samples will be analyzed in detail.

The $216 million National Aeronautics and Space Administration mission, called Genesis, is scheduled for launch in 2001. NASA announced last week that the mission had been selected for NASA's Discovery program of relatively low-cost spacecraft focused on specific scientific goals.

Genesis will travel out beyond the orbit of the moon and park at a gravitationally stable point for two years, where it will collect charged atomic particles -- ions and electrons -- traveling outward from the sun. These particles form the solar wind, which blows at about a million miles an hour and carries occasional energetic disturbances that can create storms of activity in Earth's magnetosphere and knock out electrical systems on satellites.

Solar wind particles can't easily be captured by Earth-orbiting satellites because Earth's magnetic field deflects most of the solar wind.

Los Alamos, whose Genesis contribution represents an effort of about $6 million, will provide an ion monitor and an electron monitor to determine what the ambient solar wind conditions are while particle collections are being made. Los Alamos also will build a concentrator that will use an electric field to funnel oxygen ions and create an enhanced sample of this important element.

When the collected materials -- which will total only a few millionths of a gram -- are back on Earth, scientists can do detailed studies to determine accurately the true composition of the sun.

"This will be the first mission since the days of Apollo to return extraterrestrial material for study," said Los Alamos space physicist Roger Wiens.

Current and earlier space missions have measured the most abundant elements in the solar wind, which are hydrogen and helium.

For Genesis, though, "we're interested in the one percent of solar material that hasn't been studied that well," principally different forms of the elements oxygen, carbon and nitrogen, Wiens said. "Some of the most interesting science will come from studying these isotopes."

The isotopic studies will have implications for how the solar system formed and evolved.

Dave McComas and Bruce Barraclough are leading Los Alamos' development of the ion and electron monitors.

"Los Alamos has been developing and flying space instruments such as these since the 1960s, so we've got a long track record of success," McComas said. "For Genesis, we will provide hardware very similar to what we put on the Advanced Composition Explorer and Ulysses missions."

ACE currently is traveling to the stable gravitational point called L1, the same location where Genesis will park. Ulysses is nearing completion of its first full orbit out of the plane of Earth's orbit and around the sun's poles.

The Los Alamos instrument design uses pairs of closely spaced, curved plates that are electrically charged. By varying the voltage on the plates, ions and electrons of differing energies can transit the curved pathways without colliding with the plates. Those that successfully travel the arch are counted by detectors.

These measurements tell researchers the number of particles in the solar wind, their energy and their direction of travel -- essentially a weather report on the wind.

Wiens, who has worked on the Genesis proposal for about seven years, will help project leader Donald Burnett of the California Institute of Technology investigate and select the material for the arrays of collectors that will absorb solar wind particles.

Wiens also developed a prototype concentrator, which acts like a lens to electrically focus charged particles; the prototype provides a design path for the collector that will be on Genesis.

The concentrator is especially designed to enhance the collection of oxygen isotopes. Studies of material from planets and asteroids show wide variability in the relative amounts of the different oxygen isotopes. This variability is thought to reflect conditions in the cloud of gas and dust that condensed to form the sun and planets. Measuring the oxygen composition of the sun, described in Genesis project literature as the mission's "highest priority objective," would let scientists sort out the different theories of how the solar system formed.

Barraclough, McComas and Wiens work in Los Alamos' Nonproliferation and International Security Division. Ron Moses, from the Laboratory's Theoretical Division, is helping with the solar wind concentrator design.


Last update Wednesday, 26-Nov-2003 12:47:05 PST by