As the first spacecraft to orbit an asteroid, the NEAR mission promises to answer fundamental questions about the nature and origin of near-Earth objects, such as the numerous asteroids and comets in the vicinity of Earth's orbit.
These objects are of interest for several reasons. First, they are the primary source of large bodies that collide with Earth, greatly influencing the evolution of the atmosphere and life on Earth. An asteroid collision with Earth was likely responsible for the mass extinction at the end of the Cretaceous period, and another impact in 1908 destroyed thousands of square kilometers of forest near Tunguska, Siberia.
In addition, clues to the nature of early solar system processes and conditions are preserved in various forms on small bodies like asteroids, comets, and meteorites (so-called primitive bodies). These records have been altered or destroyed on large, planet-sized bodies by processes of planetary evolution.
The near-Earth population of asteroids, in particular, is believed to contain clues to the nature of the building blocks (planetesimals) from which the inner planets, including Earth, were formed.
The NEAR mission will provide our first comprehensive scientific survey of an important class of objects found close to Earth, the near-Earth asteroids, and promises to be an auspicious beginning for the NASA Discovery Program.
Approximate Dimensions: 14 x 14 x 40 km Rotation Period: 5.27 hr Class: S (silicate rock) Surface Regolith Present Orbit Parameters: Perihelion 1.13 AU Aphelion 1.78 AU Inclination 10.8 degrees
Launch Period: Feb 16-Mar 1 1996 (15-day window) Launch Vehicle: Delta II-7925-8 Trajectory: 2-year Delta VEGA Primary Mission: Rendezvous with 433 Eros in Jan 1999 End of Nominal Mission: December 1999
Instrument Mass (kg) Power (W) Multispectral Imager System 10 7 X-ray/Gamma-Ray Spectrometer 26 31 Near-IR Spectrograph 18 9 Magnetometer 1 1 Laser Rangefinder 5 22 Radio Science * * Totals 60 70 *Part of engineering subsystems
Mass: 805 kg (includes propellant) Basic Design: Three-axis stabilized Fixed solar panels Fixed 1.5-m high-gain antenna Fixed instruments Passive thermal design Redundant critical subsystems Power: Solar powered 1600 W @ 1 AU Telemetry: X-band link to NASA Deep Space Network Size: 1.7 square-meters at the base Data Rate: Selectable between 1 to 27 kb/s Memory Capacity: 1.0-Gb solid-state Propulsion: (1) 100-lb thruster, (4) 5-lb thrusters, (7) 1-lb thrusters; total Delta V of 1420 m/s Mission Control Center: Applied Physics Laboratory Navigation Support: Jet Propulsion Laboratory
NASA Program Manager: Elizabeth Beyer NASA Program Scientist: Jurgen Rahe APL Project Manager: Thomas Coughlin APL Project Scientist: Andrew Cheng APL Mission Manager: Robert Farquhar
Go to NEAR Overview Page
Go to Small Bodies Page
Return to MSSS Home Page