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Los Alamos Ships Space Instrument For Deep Space 1 Mission

Los Alamos National Laboratory

CONTACT: Ternel Martinez, 505-665-7778

LAB SHIPS SPACE INSTRUMENT PEPE FOR EVENTUAL LAUNCH ON NASA'S NEW MILLENNIUM
DEEP SPACE ONE MISSION

LOS ALAMOS, N.M., Aug. 25, 1998 -- Scientists at Los Alamos National
Laboratory recently finished testing their part of a space instrument
designed to give a better understanding of the compositions of comets and
asteroids, and delivered the instrument for eventual integration with the
NASA spacecraft.

Los Alamos' Plasma Experiment for Planetary Exploration instrument is a
joint effort with Southwest Research Institute that is part of NASA's New
Millennium Deep Space One mission, whose primary role is to validate new
technologies that will allow NASA to better conduct future science missions.

PEPE combines two spectrometers into one package. The first spectrometer
analyzes the energy and mass of ions and the direction in which they are
traveling; the second spectrometer analyzes the energy and angular
distribution of electrons coming from all directions in space. Together,
the measurements give scientists a better understanding of the state and
composition of plasma the spacecraft encounters.

"PEPE is so versatile that it can be used almost anywhere in our solar
system. It can analyze everything from comet and asteroid composition to the
compositions of planetary bodies and moons. It could even tell you if a
nuclear or chemical explosion took place in the upper atmosphere or in
space," said PEPE Project Leader Beth Nordholt of the Space and Atmospheric
Sciences Group. Seventeen researchers from this group and the Space
Engineering Group worked on the PEPE project.

The Laboratory was responsible for constructing the "guts" of PEPE,
including its accelerator region, front-end electronics board, ion
microchannel plate and time-of-flight mass analysis section, said Nordholt.

The Deep Space One mission also will determine if the spacecraft's
innovative ion propulsion system will have any adverse affects on the
instruments' ability to make space physics measurements. "Ion thrusters
allow spacecraft to go as much as ten times faster than spacecraft using
chemical thrusters. They're also more efficient, so you need less fuel,"
explained Nordholt.

"The problem is, the ion thrusters will introduce plasma into the
surrounding environment and interact with the solar wind, and no one knows
for sure what that may do to the spacecraft or PEPE," she added. Ion
propulsion systems typically are used by communications companies to
reposition their communications satellites in orbit, but until now never
have been used for any extended space flight.

To study this effect, PEPE features three micro-electromechanically machined
calorimeters, provided by Stanford University, that will measure contaminant
deposition on the spacecraft's surface and help researchers better
understand plasma/surface interactions.

The force of the ion propulsion system that will be used on Deep Space One
is so small that the push it gives the spacecraft is analogous to the weight
of a single piece of notebook paper resting in a person's hand. However, the
spacecraft accelerates very gently. To go from 0 to 60 mph would take the
spacecraft two-and-a-half days.

Nordholt and her colleagues recently shipped PEPE to Southwest Research
Institute, which now will put the finishing touches on PEPE and eventually
ship it to NASA's Kennedy Space Flight Center for a scheduled Oct. 15
launch date. PEPE should by July 1999 make contact with the first of three
objects -- an asteroid and two comets -- to determine their compositions.

"The major benefits of PEPE are that it can provide nearly the same kind of
performance as the equivalent instruments on board Cassini for approximately
30 percent of the mass and 25 percent of the power and cost," said Nordholt.
Cassini was a joint NASA/European Space Agency effort; it launched last
October on a mission to study the composition of the rings of Saturn and the
moons orbiting within its magnetic field.

PEPE has no moving parts and weighs about 13 pounds, which translates into
greatly reduced thrust and power requirements, said Nordholt. By comparison,
Cassini's plasma spectrometer alone weighed about 50 pounds. Another major
benefit is PEPE's versatility, for its instruments can measure the energy
and mass per charge and velocity distributions of ions and electrons
simultaneously. Mass spectrometers separate and thus identify ions or ionic
fragments of the substance being measured based on their mass-to-charge
ratios.

PEPE cost about $3.6 million and took about two years to build and test. It
is one of two principal instruments on the Deep Space One mission, the other
instrument being a miniature integrated camera and spectrometer, provided by
NASA's Jet Propulsion Laboratory. Twelve advanced technologies overall make
up the mission.

Los Alamos National Laboratory is managed by the University of California
for the U.S. Department of Energy.

-30-

PHOTO CAPTION: [http://www.ucnewswire.org/]

Beth Nordholt of Space and Atmospheric Sciences (NIS-1) and Plasma Experiment
for Planetary Exploration Project Leader poses with the Lab's portion of PEPE
inside a clean room for assembly of flight instrumentation. Photo by Fred
Rick.


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