The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

294 NEAR-Shoemaker (Near-Earth Asteroid Rendezvous)
NEAR-Shoemaker (Near-Earth Asteroid
Rendezvous)
The first spacecraft to orbit and (though this was not originally
planned) to land on an asteroid—Eros. Built and
operated by the Applied Physics Laboratory at Johns
Hopkins University, the probe was originally known simply
as NEAR (Near-Earth Asteroid Rendezvous) but was
renamed NEAR-Shoemaker in memory of the American
geologist Eugene Shoemaker (1928–1997). It was the
inaugural mission in NASA’s Discovery Program and
the first probe powered by solar cells to operate beyond
the orbit of Mars.
On June 27, 1997, NEAR-Shoemaker flew by the asteroid
253 Mathilde at a distance of 1,200 km and found it
to be composed of extremely dark material with many
large impact craters, including one about 9 km deep. A
deep-space maneuver in July 1997 brought the probe
back around Earth on January 23, 1998, for a gravity
assistthat put the spacecraft on course for its rendezvous
with the Manhattan-sized asteroid 433 Eros.
NEAR’s instruments included a multispectral imager,
a telescope with a CCD (charge-coupled device) array to
determine the size, shape, and spin characteristics of the
asteroid and to map its surface; an X-ray/gamma-ray
spectrometer to determine the surface/near-surface elemental
composition; a near-infrared spectrometer to map
the mineralogical composition; a magnetometer to measure
the magnetic field of Eros; and a laser altimeter to
measure the distance between the spacecraft and the
asteroid’s surface.
Launch
Date: February 17, 1996
Vehicle: Delta 7925
Site: Cape Canaveral
Size: 2.8 × 1.7 m
Mass: 818 kg (total), 55 kg (science payload)
NEAR entered an orbit of 323 × 370 km around Eros
on February 14, 2000, then moved to gradually smaller
orbits over the next year or so, returning a total of 160,000
images. During the final days of its mission, NEAR
maneuvered to within 24 km and then, despite the fact
that it had not been built as a lander, became the first
spacecraft actually to touch down on an asteroid. NEAR-
Shoemaker was designed only to orbit Eros. But with all
of its objectives fulfilled, it was decided to try to bring the
craft in for what mission controllers called a “controlled
crash.” In the final moments before it landed on February
12, 2001, NEAR-Shoemaker returned pictures showing
surface details as small as a few tens of centimeters across.
Finally, in one of the great moments of space exploration,
NEAR-Shoemaker The location of the landing site of NEAR-
Shoemaker on the asteroid Eros. NASA
the probe landed so smoothly that its radio beacon continued
to send out a signal from its new home.
Nedelin Catastrophe
See Marsnik.
negative g
Acceleration that a subject experiences as acting from
below (feet-to-head direction). Also known as “eyeballs
up.” See also positive g (“eyeballs down”), prone g (“eyeballs
out”), and supine g (“eyeballs in”).
Neptune Orbiter
An important component of NASA’s future investigation
of the outer Solar System, including Neptune’s moon
Triton, which may be an icy, organic-rich, captured
Kuiper Belt object. The Neptune Orbiter is identified in
NASA’s Office of Space Science Strategic Plan as a potential
mission beyond 2007 but remains in the early concept
definition phase.
NERVA (Nuclear Engine for Rocket Vehicle
Application)
A program conducted by NASA and the U.S. Atomic
Energy Commission to develop a nuclear propulsion
system for use on long-range manned missions. Canceled
in 1969 because of high projected development costs, it
was intended to result in large, heavy-lift launch vehicles
capable of supplying a then-planned lunar base. NERVA
was also to have played an integral part in a proposed
manned mission to Mars, which was at one time scheduled
for launch in November 1981 with a manned landing
in August 1982.