With the Lunar Reconnaissance Orbiter (LRO) project facing a pivotal decision milestone in May, recent changes intended to reduce the complexity of the mission — and also add some new features to the project — have increased costs, but not to a degree that is out of the ordinary for the early stages of a program, according to agency officials.

Butler Hine, NASA’s deputy program manager for the Robotic Lunar Exploration Program, or RLEP, said in an April 13 telephone interview from his office at Ames Research Center, Moffett Field, Calif., that LRO’s estimated price tag has grown by 20 percent in the nearly two years since NASA’s Greenbelt, Md.-based Goddard Space Flight Center was put in charge of the mission.

He said LRO, not including launch, now is expected to cost about $370 million — or about 20 percent more than NASA’s pre-mission formulation estimate of $310 million for the Moon-mapping spacecraft.

“We have seen cost growth of about 20 percent beyond the $400 million bogey but that’s pretty normal at this stage,” Hine said. When launch costs are included, LRO’s price tag has grown by more like 30 percent to $525 million or so, Hine said.

NASA originally planned to launch LRO on a Delta 2 rocket at a cost of $89 million, according to Hine, bringing the project total to just under $400 million.

In December, Scott Horowitz, NASA’s associate administrator for exploration systems, decided to move LRO to a larger and more expensive Evolved Expendable Launch Vehicle (EELV). NASA expects to decide in the weeks ahead whether to go with a Delta 4 or Atlas 5, the main rockets developed for the EELV program.

NASA officials still are negotiating LRO’s launch services contract, but Hine said mission managers are bookkeeping the bigger launcher at $110 million to $160 million, with the hope of getting it for $155 million or less.

Assuming NASA gets an Atlas 5 or Delta 4 launch for $155 million, LRO’s price tag would hit $525 million, about one-third higher than the $400 million estimate.

Officially, NASA has yet to assign LRO a formal cost estimate against which budget performance will be tracked.

NASA’s 2007 budget request, which shows that the agency expects to spend $387.9 million on the LRO mission through launch and the first year of operations, includes the caveat: “Projects in Formulation are not mature in their development process and cost estimates are SUBJECT TO CHANGE as the project matures.”

LRO goes before NASA Administrator Mike Griffin and other members of the space agency’s Program Management Council on May 17 for its confirmation review. Griffin and his associate administrators will then decide whether LRO is ready to proceed into the next, more-intensive phase of mission development.

In preparation for LRO’s upcoming confirmation review, NASA ordered independent cost estimates of the mission.

NASA’s Independent Program Assessment Office, based at Langley Research Center, Hampton, Va., is due to brief Hine April 20 on what it calculated LRO would probably cost. Hine said he was not expecting any unpleasant surprises from the office’s estimate, which he said tracks within several tens of millions of dollars of the estimate LRO managers came up with themselves.

In addition to the independent cost estimates, NASA’s Office of Program Analysis and Evaluation hired former NASA chief engineer Daniel R. Mulville in January to lead a Lunar Robotic Architecture Study that is currently being briefed out to senior NASA managers.

Horowitz said during an April 10 press conference here that he made the switch to an EELV to reduce the technical complexity of the LRO mission and to give the spacecraft team additional weight margin should they need it.

Low lunar orbits of the sort LRO will fly are inherently unstable because of the Moon’s lumpy gravitational field. In order to maintain a steady 50-kilometer mapping altitude, LRO has to carry a lot of fuel for a spacecraft of its size. “In order to maintain orbit but not crash into the Moon, you use a lot of fuel,” Horowitz said.

Unlike the cryogenic upper stage engine used for both the Delta 4 and the Atlas 5, the Delta 2’s solid-propellant-fueled upper stage has to spin in order to maintain an even burn. Horowitz said spinning a large fuel tank of the kind NASA intends to use for LRO creates stability issues that can be complicated to correct.

The Atlas 5 and Delta 4 both offer larger payload fairings than the Delta 2, which means LRO designers have to be “less tricky” about the way they fold up the spacecraft’s deployable solar arrays, Horowitz said.

The bigger rocket also opened up the opportunity to add a secondary payload. NASA announced April 10 that had selected a $73 million Lunar Crater Observation and Sensing Satellite to launch with LRO in October 2008.

Sources familiar with the Lunar Robotic Architecture Study said it affirms the value of robotic precursor missions and recommends sending two robotic landers or a lander and a rover to the Moon in advance of sending astronauts.

NASA’s Robotic Lunar Exploration Program currently envisions sending a lander, dubbed RLEP 2, to the Moon in 2011. Some estimates for that Marshall Space Flight Center-led effort top $1 billion.

Noting that NASA still is pinning down objectives for the proposed lander mission, Hine cautioned against making too much at this early stage of fears expressed in and around NASA that the combined price tag for RLEP 2 and LRO could reach $2 billion.

“I certainly don’t have $2 billion,” he said.

Meanwhile, Mark Borkowski, the RLEP program executive at NASA headquarters, resigned unexpectedly March 31.

Hine said the program is carrying on without him. “I was really sorry to see Mark go because I thought he was a real asset,” Hine said. “We’re adjusting to it. He left a bit of a hole behind.”

NASA tapped Benjamin Neumann from the Exploration Systems Mission Directorate to serve as the acting RLEP program executive while the agency searches for a permanent replacement, according to NASA spokesman Michael Braukus.

Comments: bberger@space.com