MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
Contacts: JPL/ Martha Heil (818) 354-0850
Applied Physics Lab/Helen Worth (240) 228-5113
Mike Buckley (240) 228-7536
FOR IMMEDIATE RELEASE
February 13, 2001
JPL NAVIGATORS GUIDE NEAR TO HISTORIC LANDING ON ASTEROID EROS
With fingers flying across calculator keypads as new
guidance data flowed in, JPL space navigators yesterday used
fast math, and lots of it, to help carefully nudge NASA's NEAR
Shoemaker spacecraft to its historic touchdown on the surface
of asteroid Eros.
The success of the landing, and the spacecraft's
continuing communications with controllers via NASA's JPL-
managed Deep Space Network, astounded even the most optimistic
of scientists and engineers associated with the mission.
"Unbelievable," was how deputy navigation team chief Jim
Miller of JPL described the landing and the fact that the
spacecraft is still alive and communicating with Earth.
NEAR Shoemaker project managers at Johns Hopkins
University's Applied Physics Lab (APL) in Laurel, Md.,
reported today that the team is assessing the overall health
and performance of the spacecraft and evaluating ways to
gather additional information from the craft. A decision on
how to do that could be reached as early as today, mission
Eros is about the size of Manhattan Island. NEAR
Shoemaker landed on a rock-strewn plain of the asteroid at
12:02:10 Pacific Standard Time (3:02:10 EST) on Monday, Feb.
12. It had slowed to a gentle 1.9 meters per second (4 miles
per hour) just before finally coming to rest after a journey
of 3.2 billion kilometers (2 billion miles).
Cheers and congratulations filled the NEAR Shoemaker
mission operations center at Maryland's APL yesterday as
images and engineering data arrived from the spacecraft. APL
built the spacecraft and manages the mission for NASA.
The NEAR Shoemaker navigation team at JPL is headed by
Bobby Williams and includes Miller, Bill Owen, Mike Wang,
Cliff Helfrich, Peter Antreasian, Eric Carranza, John Bordi and Steve Chesley. JPL's Dr.
Donald Yeomans serves as the mission's radio science principal
investigator, and JPLers Jon Giorgini and Alex Konopliv are
The last image from NEAR Shoemaker was snapped a mere 120
meters (394 feet) from the asteroid's surface and covers an
area 6 meters (20 feet) wide. As NEAR Shoemaker touched down,
it began sending a beacon, assuring the team that the small
spacecraft had landed gently. The signal was identified by
radar science data, and about an hour later was locked onto by
NASA's Deep Space Network antennas, which will monitor the
spacecraft until Feb. 14.
NEAR Shoemaker's final descent started with an engine
firing at 7:31 a.m. PST (10:31 a.m. EST), which nudged the
spacecraft toward Eros from about 16 miles (26 kilometers)
away. Then four braking maneuvers brought the spacecraft to
rest on the asteroid's surface in an area just outside a
saddle-shaped depression, Himeros. When it touched down, NEAR
Shoemaker became the first spacecraft ever to land, or even
attempt to land, on an asteroid. The success was sweetened by
the fact that it was not designed as a lander.
The spacecraft spent the last year in a close-orbit study
of asteroid 433 Eros, a near-Earth asteroid that is currently
316 million kilometers (196 million miles) from Earth. During
that time it collected 10 times more data than originally
planned and completed all its science goals before
attempting its descent to the asteroid.
For mission updates, images and other information, see
JPL, a NASA center, is a division of the California
Institute of Technology in Pasadena.