The implementation of NASA Administrator Daniel
Goldin's vision of "Faster, Better, Cheaper"
planetary missions. The program's prime objective
is to enhance our understanding of the solar system,
both historically and as it is today, by exploring
the planets, their moons and other small bodies,
either by traveling to them or remotely from the
vicinity of Earth.
The first Discovery mission, Mars Pathfinder was
launched in 1996. Pathfinder arrived on Mars on
July 4, 1997, slowed in its descent by a system
of parachutes and retro-rockets, falling freely
the last few hundred feet, and bouncing on its inflated
airbags over the Martian surface like a basketball.
The airbags deflated, the petals of the lander opened,
and the rover descended and began exploring and
analyzing nearby rocks. The engineering design far
exceeded expectations. Pathfinder's lander operated
nearly three times longer than its design lifetime
of 30 days, and the Sojourner rover operated 12
times its design lifetime of seven days. After sending
back thousands of images and measurements, the mission
ended on September 27, 1997.
NEAR Shoemaker was launched on February 17, 1996.
The spacecraft entered orbit around the asteroid
Eros on February 14, 2000, and began its year-long
orbit of the asteroid to determine its mass, structure,
geology, composition, gravity, and magnetic field.
Eros is one of the largest near-Earth asteroids
whose orbit will someday cross that of Earth's.
These bodies are of interest because they contain
clues to the origin and evolution of small bodies
and the inner planets, including Earth. After a journey of more than two billion miles, NEAR Shoemaker gently landed on the tips of two solar panels and its bottom edge on February 12, 2001, at 3:01 p.m. (EST). The spacecraft snapped 69 detailed pictures during the final three miles (five km) of its descent, the highest resolution images ever obtained of an asteroid, showing features as small as one centimeter across.
Lunar Prospector, the third Discovery mission, launched
on January 6, 1998, and was successfully placed
into orbit 63 miles above the lunar surface five
days later. The science data returned from Lunar
Prospector has enabled scientists to create the
most complete and detailed maps of the gravity,
magnetic properties and chemical composition of
the Moon's entire surface. Lunar Prospector detected
large localized magnetic fields in the lunar crust,
identified rich pockets of several elements, and
returned data that seems to indicate large concentrations
of hydrogen at both lunar poles, suggesting the
presence of water ice. The spacecraft was purposely
crashed in the South Pole of the moon on July 31,
1999, in an attempt to detect ice.
Launched on February 7, 1999, Stardust is the first
space mission dedicated solely to studying a comet.
For the first time ever, comet dust and interstellar
dust particles will be collected during a close
encounter with Comet P/Wild 2 and returned back
to Earth for analysis by scientists worldwide. Stardust
made three loops around the sun before its
closest approach to the comet in January 2004. In
addition Stardust collected comet dust samples
from Wild 2 in 2004, all the samples captured in
the aerogel collector were retracted into the
sample return capsule. They will then be returned
to Earth via parachute for a soft landing at the
U.S. Air Force's Utah Test and Training Range in
The Genesis mission will send a spacecraft to collect
particles ejected from the Sun, called solar wind,
that may contain the answers. After launch in 2001,
the Genesis spacecraft will journeyed a million miles
sunward, unfolded its collectors and "sunbathe"
for two years, and will return the samples to Earth in September 2004..
The Comet Nucleus Tour, or CONTOUR, mission launched from Cape Canaveral on July 3, 2002. Six weeks later, on August 15, contact with the spacecraft was lost after a planned maneuver that was intended to propel it out of Earth orbit and into its comet-chasing solar orbit.
The investigation board concluded the most likely
cause was structural failure of the spacecraft due to plume heating
during the embedded solid-rocket motor burn.
The MESSENGER (MErcury Surface, Space ENvironment,
GEochemistry, and Ranging) mission is a scientific
investigation of the planet Mercury. Understanding
Mercury and the forces that have shaped it is fundamental
to understanding the evolution of terrestrial planets.
MESSENGER will orbit Mercury for one Earth year
following two flybys of that planet. The orbital
phase will use the flyby data as an initial guide
to perform a focused scientific investigation of
this enigmatic world.
The Deep Impact mission will send a large copper
projectile crashing into the surface of a comet
at more than 20,000 miles per hour, creating a huge
crater and revealing never before seen materials
and the internal composition and structure of a
comet. his will be the first experiment to probe
deep beneath the surface of a comet and will permit
a variety of instruments, both onboard the spacecraft
and at ground-based and space-based observatories,
to study the resulting debris and pristine interior
Last updated November 10, 2009