The San Francisco Chronicle
In a make-or-break effort to overcome its recent record of space disasters, NASA flight controllers will attempt to maneuver a new robot spacecraft called Mars Odyssey toward a stable orbit around the red planet Tuesday, October 23.
The U.S. $297 million craft was precisely on course for its final approach late Monday after a six-month voyage that carried it across 286 million miles (460 million kilometers) of space, reported David A. Spencer, manager of the Odyssey mission at NASA's Jet Propulsion Laboratory in Pasadena.
Just as the spacecraft had entered the Martian "gravity well," Spencer said during an interview that the approach over the planet's north pole was "just perfect"—so good, in fact, that he and his team of navigators decided that they would not need an extra corrective course maneuver originally planned for Monday night.
"We couldn't be more confident now," Spencer said.
But neither he nor anyone else involved in the mission was taking success for granted. Mission planners all remember the two failures of 1999 when a Mars orbiter simply vanished in space in October, never to be heard from again, and a lander aiming for the Martian south pole crashed because of navigation glitches apparently due to faulty management and testing.
"We believe we have done everything possible to make this extremely vital mission a success," James Gavin, NASA's Mars Program scientist, said in a statement.
Much is riding on this mission's success. Budget-cutters in Congress could use another failure to trim most of NASA's science programs—all, perhaps, except the highly publicized International Space Station.
The 1,671-pound (758-kilogram) Mars Odyssey's instruments are designed for science: to learn more details about the chemical nature of the Martian surface, to seek signs of buried water there, and to study the planet's radiation environment levels—essential knowledge that future Mars-bound human explorers must know well in advance.
Starting October 23, Mars Odyssey mission controllers will use an extremely delicate technique called "aerobraking" that will require three months to maneuver the spacecraft into its final orbit around the planet.
At 7:36 p.m. Pacific Time, the controllers will fire the ship's thrusters in what Spencer called "the most-high-risk event" of the flight from Earth: a crucial 20-minute burn to carry it into its first looping orbit that should bring it as close as 200 miles (320 kilometers) above the planet's north pole and as far out as 17,000 miles (27,000 kilometers) every 17 to 19 hours.
Then, during three months of continuous "aerobraking," the controllers will gradually lower the spacecraft through thicker and thicker layers of the highly tenuous carbon dioxide Martian atmosphere, where atmospheric friction gradually will slow Odyssey until, after some 400 orbits closer and closer to the planet, it enters its final orbit just 249 miles (400 kilometers) above the Martian poles.
