A NASA Group Achievement Award has been
presented to the Space Interferometry Mission (SIM) metrology beam launcher
development team, a collaboration between the Lockheed Martin Space Systems
Advanced Technology Center (ATC) and NASA’s Jet Propulsion Laboratory (JPL).
The award certificates, signed by NASA Administrator Sean O’Keefe, cite
“outstanding accomplishment in the development of a new class of picometer
laser metrology beam launcher, which will help enable the Space
Interferometry Mission.”

“We’re very pleased and proud to be recognized for this accomplishment,”
said Mike Margulis, Space Systems SIM program manager. “Our beam launcher
technology provides an accuracy two orders of magnitude beyond the current
state of the art, and will most certainly contribute to the success of the
SIM mission.” The Lockheed Martin members of the SIM metrology beam launcher
development team honored are: Larry Ames, Willy Anderson, Stephanie Barrett,
Robert Barrett, Ray Bell, Robert Benson, Gene Cross, Larry Dries, Kalyan
Dutta, Florence Escueta, Margaret Garcia, Dexter Girton, Bau Ho, Todd
Kvamme, David Leary, Roger Montross, Patrick Perkins, Mark Scott, Timothy
Van Eck, and John Woo.

The beam launchers enable measurement of the variation of 10-meter optical
pathlengths on SIM with accuracy in the tens of picometers. For a sense of
scale, a hydrogen atom is about 100 picometers in size. The beam launchers
use a technique called heterodyne interferometry to measure optical path
length with a beam of infrared laser light. After reflection off of
retroreflectors (corner cubes) at the ends of the optical path, the laser
light is returned to the beam launcher where it is mixed with a reference
signal to produce the measurement of the variation in length of the optical
path.

SIM, a major observatory in NASA’s Origins Program, will be the agency’s
first space interferometer designed specifically for measuring the positions
of stars. The ATC and JPL beam launchers are crucial in providing exact
information on the positions of the telescopes, information that is
fundamental in achieving the position measurements of objects on the sky.
The technique of interferometry, as used on SIM, will combine the light
waves from two sets of four one-foot diameter telescopes arrayed across a 10
meter (33-foot) boom. The combined light waves will “interfere” or blend
together to achieve position measurements on the sky with accuracies
approaching one micro-arcsecond. To place this in perspective, one
micro-arcsecond corresponds to the width of toothpick viewed from a distance
of 200,000 km (125,000 miles).

SIM’s precision astrometry will allow scientists to look at the 100 or so
nearest stars and determine, by inference, whether planets accompany those
distant suns. Just as the Moon exerts tidal forces on the Earth, and the
planets in our solar system cause the Sun to wobble slightly from side to
side, a planet circling another star will cause it to jiggle in its orbit.

SIM will not have the sensitivity to detect directly a planet orbiting a
nearby star, because its reflected light would be far too faint. Instead,
using precise positional measurements, SIM will be able to measure a star’s
wobble — a telltale perturbation that would herald the presence of one or
more planets orbiting the star. Using SIM’s precision optics, planets that
range in size from Uranus to Jupiter will be easily detectable, and even a
small planet the size of Earth could be inferred around a star up to 30
light years away.

SIM is managed by the Jet Propulsion Laboratory in Pasadena, Calif. for
NASA’s Office of Space Science, Washington, D.C.

Lockheed Martin Space Systems Company is one of the major operating units of
Lockheed Martin Corporation. Space Systems designs, develops, tests,
manufactures, and operates a variety of advanced technology systems for
military, civil and commercial customers. Chief products include a
full-range of space launch systems, including heavy-lift capability, ground
systems, remote sensing and communications satellites for commercial and
government customers, advanced space observatories and interplanetary
spacecraft, fleet ballistic missiles and missile defense systems.

Headquartered in Bethesda, Md., Lockheed Martin is a global enterprise
principally engaged in the research, design, development, manufacture, and
integration of advanced-technology systems, products, and services. The
Corporation’s core businesses are systems integration, space, aeronautics,
and technology services. Employing more than 125,000 people worldwide,
Lockheed Martin had 2001 sales surpassing $24 billion.

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