NASA is scrapping plans to place a dedicated telecommunications relay satellite in orbit around Mars in 2009.

With fewer robotic explorers bound for the red planet early next decade than previously anticipated, NASA has decided it can get by without the Mars Telecommunications Orbiter, a satellite conceived to handle a now-forestalled avalanche of science data.

Doug McCuistion, Mars program director at NASA Headquarters here, said the decision to cancel the Mars Telecommunications Orbiter was driven by both a diminished need for a dedicated relay at Mars and the funding requirements for other missions in astronomy, Earth science and to other planets. In addition, NASA must begin preparing for the first human lunar expeditions since the Apollo program three decades ago.

But NASA is by no means abandoning the red planet.

NASA has two orbiters and two robotic rovers exploring Mars, and three more spacecraft are bound for the red planet between this summer and 2009. NASA also still plans to launch a low-cost, competitively selected Mars Scout mission in 2011.

But long-proposed robotic missions to collect martian samples and return them to Earth for study, as well as a series of so-called human exploration precursor missions, have been put on hold for now.

McCuistion described NASA’s Mars exploration plans beyond 2010 as a work in progress, with discoveries still to be made this decade shaping what NASA does in the next. McCuistion also said NASA has not given up on sending a dedicated communications satellite to Mars, but is still assessing where such an asset fits into the program. “The need for it has diminished in the immediate term, but that doesn’t mean we have abandoned the idea,” McCuistion said.

The Mars Telecommunications Orbiter was to be built by Lockheed Martin Space Systems of Denver, the only company to bid on the project. Lockheed Martin entered into negotiations this spring with NASA and the Jet Propulsion Laboratory, Pasadena, Calif., to build the $500 million satellite, but the talks had not yielded a contract before NASA decided to pull the plug on the project.

The relay craft was meant to be the first piece of a permanent communications infrastructure intended to provide a link with Earth for all future Mars missions. The satellite also was to be equipped with a science package NASA had not yet selected and a laser optical communications experiment designed to point the way to a highly reliable method for transmitting large amounts of data back to Earth.

The cancellation of the Mars Telecommunications Orbiter means NASA will only be launching one spacecraft to Mars in 2009 — the mobile, nuclear-powered Mars Science Laboratory.

The Mars Science Laboratory is expected to return an unprecedented science haul, but McCuistion said existing Mars data relay assets — including the Mars Odyssey craft launched in 2001, the Mars Global Surveyor launched in 1996, and the soon-to-be-launched Mars Reconnaissance Orbiter — will be able to handle the science rover’s data flow back to Earth.

“We can get all the data from Mars Science Lab back without [the Mars Telecommunications Orbiter], and the Mars Reconnaissance Orbiter is a key feature in that obviously,” he said.

The Mars Reconnaissance Orbiter is slated to launch Aug. 10 from Cape Canaveral Air Force Station, Fla., aboard an Atlas 5 rocket. The $450 million satellite is equipped with a large high-gain antenna and a powerful communications package, including a Ka-band transmitter. After two years of science operations, the spacecraft will be pressed into service as a communications relay for an additional two years and perhaps as many as six.

“We actually came in light on our dry mass so we are able to add 51 kilograms more propellant on the spacecraft,” said Jim Graf, the Mars Reconnaissance Orbiter project manager at the Jet Propulsion Laboratory. “That enables us to continue to operate at our science altitude of [480 kilometers] until 2014, so the spacecraft can probably cover the Mars Science Laboratory’s lifetime.”

Even if the Mars Reconnaissance Orbiter is not still operating in 2009, for whatever reason, McCuistion said the Mars Science Laboratory mission still could go forward.

“We certainly can still do” the mission, McCuistion said. “We have Odyssey, which has fuel to last well into the next decade, and we still have Mars Global Surveyor, which will last at least until the end of this decade or longer based on fuel use, so we do have orbital assets for data relay. We also have a direct-to-Earth capability on the Mars Science Laboratory that obviously is not optimal.”

Reaction to the cancellation of the Mars Telecommunications Orbiter was mixed.

Joseph Alexander, director of the National Research Council’s Space Studies Board here, noted that Mars exploration has long commanded a large share of NASA’s space science spending and said he was pleased to see NASA Administrator Mike Griffin follow through on his pledge to restore balance to the science program. “In the grand scheme of things, there were people who felt that the emphasis on Mars was starting to come at the expense of other areas,” Alexander said. “This looks to me like a case of Griffin following through on his promise to rebalance the program.”

Louis Friedman, executive director of the Planetary Society in Pasadena, Calif., also read the cancellation as part of Griffin’s effort to juggle competing budget priorities, but he was not happy about it.

“We are very supportive of Griffin having to make moves to get the [Crew Exploration Vehicle] moving quickly and dealing with all the space station issues — including goring some oxes along the way — but taking Mars out of the exploration program, as was done in the budget cuts, and cutting back on the infrastructure for an eventual Mars outpost could create another dead-ended program with no destination and no public support,” Friedman said.

Brian Berger is editor in chief of and the SpaceNews magazine. He joined in 1998, spending his first decade with the publication covering NASA. His reporting on the 2003 Space Shuttle Columbia accident was...