Press Release

New Bulk Metallic Glass to Catch Pieces of the Solar Wind

By SpaceRef Editor
October 11, 2000
Filed under

NASA’s Genesis spacecraft, the first mission to collect and
return samples of the solar wind — fast moving particles from
the Sun — is moving closer to launch. Scheduled for liftoff in
February 2001, the mission will help scientists refine the basic
definition of the Sun’s characteristics, and understand how the
solar nebula, a large cloud of gas and dust, gave rise to our
complex solar system.

Genesis has received its final piece of science equipment: a
solar wind collector made of a new formula of bulk metallic
glass, composed of the same class of material as high-tech golf
clubs. It and other solar wind collector tiles on the spacecraft
will collect the first-ever samples of the solar wind as the
spacecraft floats in the oncoming solar stream.

“Comparing differences in what the Sun and the Earth are
made of yields interesting conclusions,” said Dr. Don Burnett of
the California Institute of Technology in Pasadena, the principal
investigator for the mission and leader of the Genesis team.
“What Genesis does is measure what the Sun is made of, so that
many important comparisons can be made.”

On its return to Earth in 2003, the sample collected by
Genesis will be retrieved in midair by helicopters. Genesis will
have collected elements of the solar wind such as isotopes of
oxygen and nitrogen. The samples will be sent to laboratories for
detailed analysis.

Bringing back samples of the solar wind will provide the
next century of scientists with a databank of solar composition.
Because the outer layers of the Sun are composed of almost the
same material as the original solar nebula from which all our
solar system came, scientists will also learn more about
meteorites, comets, lunar samples, planetary atmospheres, and how
these components evolved.

The mission is designed to measure the composition of
isotopes in solar matter, to improve knowledge about the
differing amounts of elements, and to obtain separate samples of
different types of solar wind.

The body of the spacecraft contains a canister with
collector plates that fold out like blades on a pocket knife to
collect solar wind. The ions and particles that make up the solar
wind will embed themselves and be trapped in small hexagonal
plates on the circular blades.

A disk made of a mixture of metals that has properties
similar to other glasses, about the size of a coffee cup lid,
completes the science payload. It is a unique formulation of
bulk metallic glass created especially for Genesis. The shaft on
which the plates rotate is capped with the disk of new bulk
metallic glass.

In an odd mix of science and sports, golfers and Genesis
scientists both like bulk metallic glasses, but for different
reasons. Premium golf clubs can be made with a kind of bulk
metallic glass that is hard but springy. Scientists use a type
that absorbs and retains helium and neon, important elements in
understanding solar and planetary processes.

The new bulk metallic glass-forming alloy was designed by
Dr. Charles C. Hays in the materials science laboratories of Dr.
Bill Johnson of Caltech. It is a complex mixture of zirconium,
niobium, copper, nickel, and aluminum. The atoms of metallic
glasses solidify in a random fashion, unlike metals, which have
an ordered crystalline structure. This disordered atomic state
makes metallic glasses useful in a wide range of applications,
from aircraft components to high-tech golf clubs. The Genesis
metallic glass was prepared in a collaborative effort by Hays and
George Wolter of the Howmet Corporation, Greenwich, Conn., using
the same process the company uses for the high-tech Vitreloy-
based golf clubs.

The surfaces of metallic glasses dissolve evenly, allowing
the captured ions to be released in equal layers by sophisticated
acid etching techniques developed by the University of Zurich,
Switzerland. Higher-energy ions blast further into the metal’s
surface. When samples are back on Earth, special techniques will
be used to etch the metal layer by layer, releasing the particles
of gas for laboratory study.

“One exciting thing about bulk metallic glass is that it
will enable us to study ions with energies higher than the solar
wind. This allows Genesis to test proposals that the higher
energy particles differ in composition from the solar wind,” said
Burnett. This will be the first time the theories about different
kinds of solar wind can be tested by bringing back actual
samples, he said.

To bathe in the solar wind, the spacecraft only needs to fly
about 1.5 million kilometers (1 million miles) toward the Sun
(about 1 percent of the Sun-Earth distance). When it is in the
right position — outside of Earth’s magnetic field, between
Earth and the Sun where the gravity of both bodies is balanced,
called the Lagrange point — the capsule will open its collector
arrays and let ions barrage its panels.

For more information, see the Genesis home page at
http://tiberius.jpl.nasa.gov .

Genesis is managed by JPL for NASA’s Office of Space
Science, in Washington, DC. It is part of NASA’s Discovery
Program of low-cost, highly focused science missions. JPL is a
division of the California Institute of Technology.

SpaceRef staff editor.