WASHINGTON — One week after U.S. President Barack Obama touched down at NASA’s Kennedy Space Center in Florida to defend ditching the Moon as an astronaut destination, lawmakers are still seeking to save the Ares rockets and other parts of the Constellation program targeted for cancellation in the president’s 2011 budget request.

Obama in his April 15 speech rescinded plans to cancel the Orion Crew Exploration Vehicle and called on NASA to produce a stripped-down version of the spacecraft to serve as a lifeboat for astronauts aboard the international space station. But that concession, along with a pledge to select a heavy-lift launch vehicle design by 2015, did little to placate lawmakers. Sen. Bill Nelson (D-Fla.), chairman of the Senate Commerce, Science and Transportation subcommittee on science and space, bucked the Obama administration April 21 by adding language to a nonbinding Senate budget resolution to pay for continued testing of the Ares 1 rocket in order to preserve the option of building a space shuttle-derived heavy-lift launcher.

An Ares 1 prototype built from a spare shuttle solid-rocket booster launched from Kennedy Space Center last October on a suborbital trajectory. Nelson said continued flight testing of the Ares 1 “will not only be important to the future of us getting out of low Earth orbit” but also will help maintain the U.S. capacity to build the large solid-rocket motors used on strategic missiles and satellite launchers.

Senate Budget Committee Chairman Kent Conrad (D-N.D.) also invoked national security concerns when he endorsed Nelson’s call for carving out an additional $1 billion for NASA in the Senate’s 2011 budget resolution, which sets the guidelines for the spending bills Congress is just now starting to draft.

“There are classified discussions that we can’t go into here, with respect to this initiative, but I’d say to my colleagues this is absolutely essential for the national security that this go forward and I think every member of this committee understands what I’m talking about so I hope very much that this will be retained and we’re going to have to fight for this,” Conrad said.

The following day Rep. Pete Olson (R-Texas) said the president’s pledge to choose a heavy-lift rocket design by 2015 and develop a stripped-down version of the  Orion capsule being built by Denver-based Lockheed Martin Space Systems does little to address what many lawmakers see as an urgent need for heavy lift.

“I don’t understand why we don’t put energy and resources into developing a heavy-lift rocket now,” he told an audience of congressional aides and industry representatives during an April 22 breakfast on Capitol Hill. “Based on what we learned from the Constellation program, there’s no need, no need, to wait to 2015 to make that decision.”

Meanwhile, Constellation program officials have been quietly evaluating options for restructuring the Ares and Orion contracts to create incremental development and test programs that would cost much less in the near term than the $6 billion to $7 billion per year the agency expected to spend once it shifted its race to the Moon into overdrive.

According to government and industry officials involved in the effort, the notional program starting to take shape entails building and testing progressively more advanced Ares and Orion prototypes en route to the first crewed test flights around 2015 and a circumlunar mission around 2018, to be followed by longer duration jaunts beyond low Earth orbit.

Obama, in his April 15 speech, charted a similarly gradual approach for venturing beyond Earth orbit and setting a course for an asteroid in 2025. While Obama implied that Orion could play a part in technology-demonstration flights that would precede such a mission — he called Orion “part of the technological foundation for advanced spacecraft to be used in future deep space missions” — the president gave no such indication that Ares might still have a future.

NASA Administrator Charles Bolden, testifying before the Senate Appropriations commerce, justice, science subcommittee April 22, said he likes the idea of using Orion as the basis of an incremental approach to developing a future deep-space capsule.

Bolden said he would like to see “the restructuring of the Orion program …  be an incremental approach to develop a vehicle that will one day take us to the Moon and Mars and beyond low Earth orbit.” Bolden said that the Orion lifeboat could be developed within three years, would have no need for a man-rated rocket to deliver it to orbit and would provide a U.S. capability to get crews back from space station sooner than commercial firms will be able to field their envisioned human-rated crew transport systems.

During the hearing the subcommittee’s chairwoman, Sen. Barbara Mikulski (D-Md.), said it was not clear to her whether the White House is still seeking to cancel the Constellation program, or just restructure it.

“This is of very, very, very keen interest in our committee,” she said.

Mikulski also said lawmakers need more information before they give the White House the congressional authority it needs to remake a human spaceflight program that the previous administration overhauled in 2004.

“I want to know if this is the program that the Congress and the American people are going to support from one administration to the next,” she said. “We cannot reinvent NASA every four years. Every new president can’t have a new NASA agenda.”

Sen. Richard Shelby (R-Ala.), whose state stands to lose thousands of jobs at NASA’s Marshall Space Flight Center in Huntsville if Constellation is canceled, said an Orion capsule designed for use as a “space station escape pod” would not lessen U.S. reliance on other nations.

“The president’s plan only ensures that for decades to come the United States will be subservient to and reliant on other countries for access to space,” Shelby said. “This request I believe abandons our nation’s only chance to remain the leader in space and instead chooses to set up a welfare program for the commercial space industry.”

In written testimony to the committee, Bolden said docking the Orion lifeboat, which he dubbed the Emergency Return Module (ERM), to the station would fulfill “a portion of our commitment to the International Partners that was neglected under the previous plan.”

NASA stopped development of a seven-person lifeboat, called the Crew Return Vehicle, in 2002 when it scaled back the international space station to address a multibillion-dollar budget shortfall. Under Constellation, NASA planned to rely on the three-seat Russian Soyuz capsule for routine astronaut transport and crew escape until Orion was ready to enter service. With Obama’s revisions, NASA and its non-Russian partners might not need to count on Soyuz for crew escape beyond 2013, but would still continue to rely on Soyuz for routine transport until U.S. commercial alternatives come on line a few years later.

Bolden said funding for the Orion lifeboat would come from offsets to other parts of the $4.26 billion budget the White House proposed for NASA’s Exploration System Mission Directorate for 2011. An updated budget proposal, he said, would be sent to Congress “in the next few weeks.”

Sen. George Voinovich (R-Ohio) praised the administration’s proposal to invest more money in next-generation space technologies at NASA’s Glenn Research Center in his home state, but said Bolden must do more to explain the rationale for canceling Constellation.

“You’re going to have to do a big job convincing this committee about … what you’re doing with the money we’re going to make available to you,” Voinovich said. “Many of us are interested in whether or not the money that we’ve already put into Orion is going to be poured down the drain or whether or not it’s going to be able to stay in the game in terms of competition in order to go forward with this because of all the work that’s been done.”

Sen. Kay Bailey Hutchison (R-Texas) expressed skepticism with NASA’s plan to rely on commercial crew taxis to ferry astronauts to and from the space station.

“The emphasis to the tune of $6 billion into a very fledgling commercial capability I just think is not sound and it’s certainly not going to be reliable,” she said, adding that it would be premature to rely on Hawthorne, Calif.-based Space Exploration Technologies (SpaceX) and Dulles, Va.-based Orbital Sciences Corp. to deliver crews to low Earth orbit. Hutchison said NASA’s two Commercial Orbital Transportation Services (COTS) providers are, in her opinion, “not ready for this kind of reliance and I don’t think we can take that kind of chance.”

Shelby also criticized Obama’s plan to rely on the private sector to develop and sustain NASA’s human spaceflight capabilities and questioned the administration’s failure to conduct an independent analysis of the commercial market for space tourism.

Shelby also said the president’s budget rewards NASA’s COTS providers, whose efforts to field new rockets and cargo capsules are behind schedule.

“Today the commercial providers that NASA has contracted with cannot even carry the trash back from the space station much less carry humans to and from space safely,” he said, disparaging Obama’s request for an additional $300 million in 2011 to help increase the likelihood that Orbital and SpaceX come through with their promised cargo-delivery systems.

Shelby personally blamed Bolden for the plan to abandon development of the Ares rockets and retain only a slimmed-down version of Orion.

“Your destructive actions toward the Constellation program will only ensure that members cannot trust you,” he said. “Mr. Administrator, you are creating an atmosphere where you and your leadership team have become a major impediment, I believe, to moving forward.”

Later Shelby said, “It’s clear that the administration, and more specifically you, Mr. Administrator, do not believe that American leadership in human spaceflight is a priority worth fighting for.”