Mars Exploration Program Fact Sheet
The Mars Exploration Program will continue exploring the Red Planet,
which has fascinated humankind for thousands of years. Robotic spacecraft
began visiting Mars in 1965 and landed on its surface in 1976. Mars was
found to be a planet of stark contrasts. Surface features range from ancient,
cratered terrain like Earth's Moon to giant volcanoes and a canyon as long
as the United States is wide. The atmosphere is only 1% as thick as Earth's,
but there are year-round polar caps with reservoirs of water ice. Close
up, Mars resembles an earthly desert like California's Mojave, but there
is evidence that water once flowed and cut channels on the surface.
The new, ongoing program of Mars exploration is initially focused on three
major objectives: searching for past or even present life, understanding
the Martian climate and its lessons for the past and future of Earth's climate,
and searching for resources of possible use by future human missions. The
unifying theme of these objectives is water, which is a key requirement
for life, a driver of climate, and a vital resource. Therefore, early missions
will partially focus on finding and understanding the past and present state
of water on Mars. This exploration will begin with launches in late 1996
of the Mars Global Surveyor and
Mars Pathfinder missions and may
lead to human missions to Mars as early as the year 2018.
Mars Pathfinder will be the second mission in the Discovery program of planetary
exploration. It will launch in December 1996 on a McDonnell Douglas Delta
II rocket (capable of throwing about 1000 kg to Mars). Pathfinder will fly
directly to Mars and plunge into the atmosphere at 17,000 mph (27,000 km/hr,
7.6 km/s) without going into orbit. Using a combination of a heat shield,
parachute, rockets, and airbags, Pathfinder will land on the surface in
an ancient flood plain, which is expected to be littered with a wide variety
of rocks. Pathfinder will image the Martian terrain in 13 different colors,
monitor the weather, and deploy a small rover to explore the region around
the lander and measure the composition of the surface.
Mars Global Surveyor is the first in a series of missions called the Mars
Surveyor Program. This program will fly two missions to Mars at every launch
opportunity (about every 26 months), and, with Pathfinder, is pioneering
the "better, faster, cheaper" approach to planetary missions.
Mars Global Surveyor will launch in December 1996 (also on a Delta II),
and will go into orbit around Mars in September 1997. It will use "aerobraking,"
skimming through the upper part of the thin Martian atmosphere, to go from
a long, looping orbit into a circular polar orbit. It will scan the surface
of Mars for a full Martian year (about two Earth years) using spares from
six of the eight instruments originally flown on Mars Observer (which was
lost in 1993-the first planetary spacecraft failure in 27 years).
A computer-rendered image of the proposed camera to fly on Mars
Surveyor 98
In late 1998 Mars Surveyor 98 will launch an orbiter and a lander on a Delta-derived
"Med-Lite" launch vehicle. The Med-Lite will only be able throw
about 500 kg to Mars, but it will cost considerably less than a Delta II.
The orbiter will carry an infrared spectrometer to survey the atmosphere
over a yearly cycle. The lander will come to rest near the south pole of
Mars and will carry a payload, including a robotic arm, which will excavate
Martian history by trenching down through thin layers of dust (and possibly
ice) deposited every year like tree rings. The polar lander will also chemically
analyze the soil, including a search for organic molecules to shed light
on whether Mars ever developed life.
Another element of the lost Mars Observer payload (a gamma ray spectrometer)
will search for water in 2001 on the Mars Surveyor 01 orbiter, and another
lander (perhaps including a more capable rover than Pathfinder's) may explore
the ancient highlands of Mars in areas where water once flowed. The 2001
lander may analyze rocks to determine the ancient history of the climate
and geology of Mars. The 2001 mission may be conducted in partnership with
the Russians, and if so, it could include a balloon or a large rover.
The Mars Surveyor program is exploring a partnership for 2003 (Intermarsnet
03) with the European Space Agency to launch three U.S. landers with international
payloads on a European rocket (Ariane 5). Intermarsnet would include a European
orbiter, and would place three landers on the surface. The landers would
explore the interior of the planet using seismology to detect "Mars
quakes." In addition, a separate United States mission may be flown,
perhaps deploying a "network" of tiny weather stations around
the planet.
And the Mars Surveyor 05 mission may be the first in a series of missions
to return a sample from the Martian surface. Again, this mission could be
in partnership with the Russians and/or Europeans. Another possible sample
return target is the Martian moon Phobos, and the Russians are especially
interested in this mission.
Each of these robotic missions will be gathering information needed to plan
future human missions to Mars. The robots will find and scout safe and interesting
human landing sites, characterize the atmosphere and surface environments
so that human missions can be designed properly, and look for water and
other resources needed by humans. The missions will also develop technologies
(such as very low mass electronics) important for human space flights to
Mars.
Over the next couple decades, the robotic phase of the Mars Exploration
Program will result in detailed knowledge of Mars, which is also important
for understanding more about the Earth's environment. Eventually, robotic
exploration will help prepare for future human exploration. The entire program
will be conducted for about one-third the cost of the Viking missions, which
orbited and landed on Mars twenty years ago. Each mission costs about the
same as a major motion picture, and the total cost of the first 10 missions
to Mars will be about that of a single major military aircraft.
NASA is currently developing a long range "road map" for the human
exploration of Mars. The road map builds on the capability of the international
space station to understand how people can live and work in space. Trips
to Mars will utilize new launch vehicle technologies now beginning development,
including re-usable rockets and improved expendable rockets. The use of
commercial technologies, such as advanced electronics will greatly reduce
the cost of human exploration of Mars. A current goal of the road map is
to enable the first human Mars mission to launch in 2018.
Humans on Mars, in partnership with robots, will explore the planet in more
detail than robots alone can. Human presence may be required to finally
answer the question of whether Mars has or once had life, a question with
vast implications for possible life elsewhere in the universe. Humans will
also investigate use of Martian resources to make the planet more easily
habitable for future generations. And finally, our children or grandchildren
may become citizens of Mars!
--Donna Shirley
