From The "JPL Universe"

November 13, 1998

New Mars plan targets sample return.
International effort to pave way for robotic colonies by 2010


A new architectural blueprint for international robotic exploration of Mars, resulting in the return of several samples of Martian material to Earth by 2008 and founding of the first permanent robotic colonies by the end of that decade, has been launched by NASA and its international partners in space exploration.

"This plan paves the way for the return of as many as four samples of Martian material from four different sites by 2011, and will lead to the establishment of the first robotic outposts and, eventually, human colonies on Mars," said Norman Haynes, Mars Exploration Program director at JPL.

Under a new plan drafted by NASA and its French, Italian and European counterparts, the consortium of spacefaring nations will begin development of affordable spacecraft and innovative new technologies to obtain in-situ measurements and samples of Martian material in preparation for human exploration of the planet. The plan calls for construction of a fleet of affordable launch vehicles, orbiters, landers, rovers and Mars ascent vehicles designed to wage an all-out effort to begin returning samples of the Martian regolith as early as April 2008.

"This plan lays out the whole framework for our next quantum leap in Mars exploration," said Dr. Charles Elachi, JPL's Space and Earth Sciences Program director and head of the architecture study. "The establishment of the first permanent robotic colonies on Mars, capable of harnessing the planet's natural resources to build a technology base for space flight to and from the planet and biospheres for human settlements well within the lifetimes of our grandchildren, is the most exciting prospect awaiting us as a global community."

The new Mars architecture plan, which is currently being refined by NASA and participating space agencies, underscores the roles and responsibilities of the four space agencies in formulating an integrated, international roadmap for the exploration of Mars.

According to Haynes, the study focuses on robotic surface activities during the early launch opportunities beginning in 2001 through 2011. Many of the early missions will focus on studies of the Martian surface involving science payloads designed to conduct chemical analyses of rocks and soils, obtain rock core samples and tap subsurface water reservoirs and other natural resources that could be used to manufacture propellants to fuel sample-return vehicles.

Work on the architectural redesign began in June. Eight "tiger teams" of experts from the international scientific community, led by Elachi and Dr. Frank Jordan, manager of JPL's Mars Program Planning and Architecture Office, were formed to address issues of spacecraft design, innovative technologies and science goals for missions beginning in 2003, as well as for achieving the overall goals of the long-range Mars Surveyor Program. Recom-mendations were presented to NASA Administrator Daniel Goldin on Sept. 24 and, subsequently, approved for implementation.

New requirements for the 2001 Mars missions, brought about earlier in the year by Congressional markups of the fiscal year 1999 NASA budget, prompted the redesign effort. The Mars 2001 project went to work to hammer out a compromise of scientific instruments on the proposed orbiter, lander and rover to meet new budget and spacecraft mass requirements.

Under the current mission architecture, the Mars 2001 lander will be equipped with a robotic arm and descent camera to explore materials buried below the Martian surface. The spacecraft will also carry a panoramic camera and mini-thermal emission spectrometer, which was part of the originally proposed payload, and a Moessbauer spectrometer designed to study Martian materials.

Three human exploration experiments developed under NASA's Human Exploration and Development of Space (HEDS) Enterprise are also included in the lander payload: the Mars Environmental Compatibility Assessment Project experiment, an instrument to investigate potentially hazardous atmospheric conditions that could affect human exploration; a Mars propellant production experiment to explore the feasibility of using atmospheric carbon dioxide to manufacture fuel for return vehicles; and a Mars radiation experiment to detect hazardous amounts of the substance in the Martian atmosphere.

In addition, a simpler, lighter-weight rover modeled after Mars Pathfinder's Sojourner rover was chosen to replace the original, more sophisticated and costly roving vehicle. The new rover, nicknamed Marie Curie, will carry an alpha proton X-ray spectrometer similar to the spectrometer carried on the Sojourner rover to study the chemical composition of rocks and surface soils and a second Mars radiation experiment to detect harmful levels of radiation on the Martian surface.

NASA will begin the series of sample-return mission in 2003, with launch of a lander and a rover that will spend several months searching for and collecting rock and soil samples, said Dr. Daniel McCleese, chief scientist and manager of the Office of Strategy and Science Programs for JPL's Mars Exploration Directorate. The roving vehicle will return the sample to a new, low-cost, low-mass Mars ascent vehicle.

Conceived by Brian Wilcox of the JPL Mars Exploration Technology Development Division, the Mars ascent vehicle is the centerpiece of the program's overarching, short-term goal to explore the Martian subsurface robotically. The vehicle is a simple rocket with with a three-stage, spin-stabilized ascent system, solid-rocket motors, minimal onboard guidance and virtually no moving parts. The launcher, which weighs about 100 kilograms (220 pounds) or less than 30 percent of previous Mars ascent vehicle designs, will place soil and rock sample canisters into a low-Mars orbit, where they will await pick-up by orbiters arriving at Mars beginning in 2005.

NASA will also provide a Boeing Delta 3-class launch vehicle and an Earth entry capsule comprised of a crescent-shaped heat shield and crushable foam material that will shield the Martian soil and rock samples when they plummet to the floor of a desert in Utah in spring 2008.

In partnership with the French space agency, Centre National d'Etudes Spatiales (CNES), NASA will also work toward developing a small "microspacecraft" weighing less than 200 kilograms (440 pounds) for delivery to Mars during this launch opportunity, Elachi said. CNES has agreed in principle to providing a piggyback ride to Mars on its Ariane 5 launch vehicle, which is capable of placing the Martian microspacecraft on a geosynchronous transfer orbit above Earth. If flown, the miniature spacecraft would use its own propulsion and gravity assists from the Moon and Earth to gain enough momentum to reach Mars.

Another collaborative arrangement with the Italian space agency, Agenzia Spatiale Italiana, will add a drill and other robotic elements to the 2003 Martian lander and those following in its footsteps. Additional robotic elements will include radio relay equipment to support the European Space Agency's proposed "Mars Express" orbiter, which will be used for data transmission from landers arriving at Mars in future years. The European Space Agency also plans to supply a sounding radar for the mission.

In 2005, a single Ariane 5 launch vehicle carrying a duplicate of the 2003 lander, rover, Mars ascent vehicle and French orbiter will be launched to Mars. The lander, with its companion rover and ascent vehicle, will land at a different location, collect a second sample of Martian rocks and soils and loft it into low-Mars orbit.

The orbiter will be inserted into a highly elliptical Mars orbit, aerobrake to low-Mars orbit, rendezvous and dock with the 2003 orbiting sample container and then rendezvous and dock with the 2005 sample. After 11 months in orbit, the spacecraft will fire its rocket engines to inject itself and the two Earth entry capsules on an Earth-return trajectory. The orbiter will target the two entry capsules carrying Martian samples onto impact trajectories, deploy them and then deflect its own trajectory so that it does not crash into Earth.

Two options are currently on the table with NASA and the French space agency for inserting the 2005 orbiter into Mars orbit. The first option would be to use propulsive maneuvers to lower and circularize the spacecraft's orbit. The second option would be to use a technique called "aerocapture," which is similar to aerobraking but would slow and directly capture the spacecraft in orbit in one step, rather than gradually slowing and lowering the spacecraft through a series of "walk-in" phases used in the aerobraking strategy. With aerocapture, the orbiter would be able to reach its final, circular mapping orbit within about one week instead of approximately nine months.

If international participation and the budgetary outlook remain stable, a total of six samples from six separate locations on the surface of Mars will have been returned by 2013, Haynes said.

To realize this scenario, another Delta 3-class launch vehicle would be used in 2007, carrying a lander, rover and Mars ascent vehicle. The samples collected would be cached on orbit to await pick-up by the 2009 orbiter. In 2009, two launches using Delta 3-class launch vehicles would follow suit. The orbiter would be the first vehicle to be launched, followed by a second lander, rover and Mars ascent vehicle. A French orbiter would collect the Mars samples from both the 2007 and 2009 landers and deploy them on return trajectories to Earth. If successful, that mission scenario would be repeated in 2011 and 2013.

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