One year after Columbia's disintegration over Texas, NASA has been charged with a radically different mission _ go back to the moon and then on to Mars. For an agency still trying to get astronauts back into space, it's an ambitious agenda. Here's a look at NASA's major programs and what the future may hold:
THE SPACE SHUTTLE
In short, the shuttle's days are numbered. Originally conceived as a kind of space plane in the Nixon administration, the shuttle is a dinosaur by today's technology standards. In fact, NASA's most up-to-date technical guide was published in 1988, though their Web site says it "is still accurate today."
President Bush's plan would retire the shuttle fleet around 2010 after completion of the international space station. Each shuttle was designed to fly 100 missions, but none will come close to that.
The remaining missions will support U.S. commitments to the space station, including transportation of crew, supplies and materials for construction and components for scientific experiments. They will also provide a platform for attaching additional modules and other components to the station.
William Gerstenmaier, NASA space station program manager, has said it may take as many as 28 shuttle missions to complete the agency's obligations.
In order to finish on the new schedule, the shuttle will need to average 4.8 missions per year. In the years before Columbia's accident, it only averaged 4.5.
Shuttle's tentative return to flight schedule
Flight STS(+)-114 STS-121 STS-115 STS-116
Shuttle Atlantis Discovery Atlantis Discovery
Target No earlier No earlier No earlier No earlier
launch than than than than
Sept. 12 Nov. 15 Feb. 10, April 14,
Mission Return to Return to Transport Transport
flight test flight test elements elements
mission; mission; for space for space
transport space station station
elements station completion completion
for space crew
(+) STS= Space Transportation System
Even though they have published a schedule, NASA's Return-to-Flight Task Group said recently it still is too soon to know when shuttle flights might resume. NASA shuttle managers acknowledged that the schedule might be too optimistic, meaning the next flight could be delayed, perhaps to early 2005. All other missions after these four are under review.
How much life?
On Oct. 11, 2000, Discovery launched on the 100th mission of the shuttle program. By January 2003, when the Columbia flew its final mission, the shuttle fleet had flown 113 missions, with the following breakdown for each orbiter:
COLUMBIA: 28 missions Lost on Feb. 1, 2003
CHALLENGER: 10 missions Lost on Jan. 28, 1986
DISCOVERY: 30 missions
ATLANTIS: 26 missions
ENDEAVOUR: 19 missions
See an archive of Columbia's last flight and the investigations that followed at spaceflight.nasa.gov/shuttle/index.html
JAMES WEBB SPACE TELESCOPE
The James Webb Space Telescope (JWST) is an orbiting infrared observatory that will replace the Hubble Space Telescope. It will study the universe during galaxy formation to show the birth of stars and planetary systems similar to our own. It will give scientists a better understanding of the intriguing dark matter problem. Its instruments will detect infrared light 400 times fainter than any current infrared telescope.
James E. Webb (1906-1992) was NASA's second administrator (1961-68) and is most closely linked to the Apollo moon program. As early as 1965, Webb said a space telescope should become a major NASA effort. The result was the 1990 launch of the Hubble Space Telescope.
Unlike the Hubble, the Webb would be too distant to be serviced after launch. The gravity of the sun and Earth hold the spacecraft in a circular orbit about 940,000 miles from Earth.
See what the Webb telescope will study at ngst.gsfc.nasa.gov/science/
BACK TO THE MOON
The Bush plan calls for a return to the moon as early as 2015 and no later than 2020. A series of robotic missions, similar to those now on Mars, will be the first step, most likely within four years.
Why the moon?
+ There's still a lot of research left to do. For example, the Apollo missions of the '60s and '70s left unanswered questions about the moon's origin.
+ An extended presence could provide an opportunity to use some of the moon's resources, including the large amounts of silicon, a prerequisite for solar power.
+ If the moon is used as a launching pad for missions deeper into the solar system, less fuel would be expended trying to escape its low gravity than from Earth.
+ As an astronomical base, the moon is far superior to the Earth. It has no atmosphere to interfere with optics and its far side is shielded from the Earth's radio transmissions.
CREW EXPLORATION VEHICLE
The proposed Crew Exploration Vehicle would allow astronauts to conduct extended lunar missions as early as 2015, with the goal of living and working on or near the moon for increasingly extended periods.
NASA'S BUDGET: CHANGING PRIORITIES
With fiscal restraints and President Bush's directives in mind, the structure of NASA's budget will change enormously over the next 15 years. Exploration missions to the moon and beyond will consume a much higher proportion of the budget as the shuttle and international space station are phased out.
HUBBLE SPACE TELESCOPE
The Hubble Space Telescope was launched in 1990. Although it was plagued by problems for its first three years, shuttle missions to replace the optics enabled Hubble to become one of the most important science projects ever.
Its position in space lets lets astronomers make exceptionally detailed observations that are impossible from Earth because of atmospheric distortion. It can access the ultraviolet and infrared spectra not visible from the ground.
Named for astronomer Edwin Powell Hubble (1889-1953), who proved the existence of other galaxies and gave proof of an expanding universe.
See pictures taken by Hubble at hubble.nasa.gov/image-gallery
INTERNATIONAL SPACE STATION
Envisioned as the leading part of U.S. research in space, the international space station has undergone several incarnations. Cost overruns and schedule problems have plagued the station, which was originally planned to be completed in 2002. Since the shuttle program's halt, it has been serviced by Russian Soyuz capsules.
Some of the scientific research done on the station has focused on protein and crystal development and fluid dynamics, taking advantage of the microgravity climate onboard to do work that can't be done in Earth's gravity. From this point on, though, research is likely to shift to examining the effect of prolonged time in space on the human body.
With a volume of 46,000 cubic feet, the station has roughly the working area of a three-bedroom home. It goes around the Earth 15 times per day and has completed nearly 30,000 orbits since the first module was launched in 1998.
The station is a joint venture of the United States, the European Space Agency, Brazil, Canada, Japan and Russia.
Track the space station's progress at spaceflight.nasa.gov/station
Want to see when the space station will fly over you? Go to spaceflight1.nasa.gov/realdata/ sightings/cities/index.cgi
WHY GO TO MARS?
Outside of the Earth-moon system, Mars is the most hospitable body in the solar system for humans and is currently the only prospect for future human exploration and colonization. It will take decades of planning and preparation, though, and require using technology that has not yet been invented.
1. PROBLEM: Everything for the trip (the supplies, material and crew) are currently on Earth.
SOLUTION: Build Mars vehicle in loe-earth orbit (like on the space station). Launch from orbit will require less rocket power because of lack of gravity.
2. PROBLEM: Round trip flight to Mars with chemical-fuel rocket takes 14 months.
SOLUTION: Develop new rocket propulsion technology, such as ion and nuclear-thermal propulsion, to increase speed, reducing travel time.
3. PROBLEM: Having enough supplies to sustain astronauts for an extended stay on Mars.
SOLUTION: It wouldn't be possible to carry everything on the Mars rocket. Some needed supplies will have to be made on Mars. Scientists say carbon dioxide in the martian atmosphere can be converted into water for human use and into fuel for a return trip.
4. PROBLEM: Getting the Mars astronauts back to Earth.
SOLUTION: Send a fully fueled Earth Return Vehicle to Mars separately. When the mission is complete, astronauts would abandon the vehicle they used to land and ride the ERV back to Earth.
Shuttle program begins
Shuttle fleet return to service
Shuttle fleet to retire, U.S. commitment to the space station to be fulfilled.
Robotic exploration on the moon
Test manned space exploration vehicle
Establish a permanent U.S. lunar station.
Lunar-based probes, landers explore the solar system, paving the way for manned missions.
WEBB SPACE TELESCOPE
Webb telescope to be launched.
INTERNATIONAL SPACE STATION
First two components, Unity and Zarya, launched
First crew mans ISS
Focus research at the space station on the effects of space flight on human health
U.S. commitment to ISS to be fulfilled. Resupply via Soyuz
Mars Observer (U.S.)
Mars Global Surveyor (U.S.)
Mars 96 (Russia)
Mars Pathfinder (U.S)
Mars Climate Orbiter (U.S.)
Mars Polar Lander (U.S.)
Deep Space 2 (U.S.)
Mars Odyssey (U.S.)
Mars Express (ESA)
Beagle 2 (U.S.)
Mars Reconnaisance Orbiter (U.S.)
Remote Sensing Orbiter (France)
Communications Orbiter (Italy)
Science Laboratory Rover (U.S.)
Scout Mission (U.S.)
Land man on Mars
Sources: NASA, the White House, Reuters, KRT, AP, Time, the Guardian, Houston Chronicle, USAToday, the Washington Post, Boeing, space.com, howstuffworks.com, New Scientist, National Geographic