WASHINGTON — House lawmakers released a draft of NASA authorizing legislation July 19 that would continue much of the work being done under the agency’s Constellation program with a focus on fielding a government-owned system capable of ferrying crews to and from the international space station by the end of 2015.

The bill text, issued by the House Science and Technology Committee, backs U.S. President Barack Obama’s proposal to spend $100 billion on NASA over the next five years. But whereas Obama’s plan would allocate $5.9 billion over that time period to foster development of commercially operated space taxis, the House bill provides just $250 million, with an additional $500 million to come via a government-backed loan program. In addition, the legislation would authorize $22.6 billion through 2015 to develop rockets and spacecraft that leverage NASA’s roughly $10 billion investment in Constellation, a 5-year-old effort to build hardware optimized for lunar exploration that Obama proposed abandoning in his 2011 budget request.

“This is a bipartisan bill that embraces many of the president’s goals for our space program while also ensuring that we have an executable and fiscally responsible plan,” Rep. Bart Gordon (D-Tenn.), chairman of the House Science and Technology Committee, stated in a joint news release issued late July 19.

“For too long, the tasks NASA has been asked to undertake haven’t been matched to available resources,” Gordon said, adding that his panel intends to mark up the bill July 22. “We are facing tough economic times that demand tough choices. We can’t do it all. This bill makes those choices and provides the nation with a credible, sustainable, and worthy space and aeronautics program.”

Although the bill supports elements of Obama’s plan, including a plan to continue flying the space station through at least 2020 and a space technology program designed to spur innovation, it rebuffs the White House proposal to cancel Constellation and rely on commercially owned and operated vehicles to send astronaut crews to the orbiting outpost. It also contrasts with companion legislation approved by the Senate Commerce, Science and Transportation Committee July 15, touted as a compromise by its authors, that provides $1.3 billion for commercial crew initiatives over the next three years.

Both the House and Senate measures would require NASA to immediately begin work on a heavy-lift rocket that leverages the space shuttle solid-rocket motor technology that serves as the foundation of the Ares rockets designed as part of the Constellation program. Obama’s plan is to scrap the Ares rockets and have NASA spend the next five years studying heavy-lift options utilizing engines fueled by kerosene and liquid oxygen.

Obama directed NASA to settle on a heavy-lift launcher design by 2015. The Senate bill calls for a heavy-lift vehicle and deep space capsule to be fully operational by the end of 2016; the House bill would give NASA six months from the date of enactment to select a launch vehicle design and sets a goal of fielding the rocket by “the end of the current decade.”

Bretton Alexander, president of the Commercial Spaceflight Federation here, said the House bill would do little to narrow the gap between the space shuttle’s scheduled retirement next year and a follow-on capability, forcing NASA to rely on Russia to deliver U.S. astronauts to the space station until a U.S. domestic capability is re-established.

“Based on the proposed levels of funding for Russian Soyuz flights versus commercial crew services, it would appear that the House Science Committee has more faith in Russian technology developed in the 1960s than in America’s own aerospace industry,” Alexander said in a July 19 e-mail, asserting that the bill fails to fund the goals it sets for the agency. “At a time when private companies are willing to invest their own money to help create jobs, the House Science Committee bill is a clear job destroyer.”

In the news release, the House Science and Technology Committee said its measure would authorize $4.9 billion for “commercial crew- and commercial cargo-related initiatives.”

According to the bill text, commercial crew programs would get just $50 million annually through 2015 and another $500 million over that same time period via direct government loans or loan guarantees. Although the bill fully funds the $4.2 billion sought for routine commercial cargo resupply runs to the space station starting in 2011, it reduces the president’s $312 million request for NASA’s Commercial Orbital Transportation Service (COTS) program next year to just $14 million. The Senate version provided $300 million for the agency’s COTS providers in 2011.

A House Republican staffer said the loan program is designed to ensure that U.S. taxpayer money is reimbursed — with interest — before the government risks billions of dollars to nurture a commercial crew transportation industry.

“By offering a loan and loan guarantee program, we hope to leverage the talents of the free market and at the same time hopefully reduce wasteful and unproductive efforts,” the aide said. “The bill provides up to half-a-billion dollars to companies that demonstrate responsible, rational and credible plans. If a legitimate, free-market-based business case for commercial crew can be demonstrated, then borrowers will be able to repay the loans to NASA, allowing the taxpayers to reap some of the financial rewards for making such a large capital outlay.”

The House measure also would require NASA to hold privately developed space taxis to the same safety standards the agency enforces for government-owned and -operated systems. The bill further directs that the per-seat cost for commercial crew systems not exceed that of the government-owned capabilities called for in the legislation.

Although the measure would limit use of the government-owned system “once commercial crew transport and crew rescue services meeting safety requirements become operational,” it would also require commercial space firms to give NASA “ongoing insight into the design methodologies, processes, technologies and other information employed in the development and production of a commercial transportation system,” the draft document states. In addition, NASA would need to sort out “all indemnification and liability issues” associated with commercial crew space taxis before awarding contracts to private firms.

Unlike the Senate bill, the House measure does not call for an additional shuttle mission to the space station, though it does fund a shuttle work force transition program and requires NASA to initiate a detailed study of space station cargo resupply needs and capabilities through 2020. It also directs NASA to study options for deploying a variable-gravity centrifuge to the space station and develop a strategic plan for life and microgravity sciences research aboard the orbiting outpost.

“The House NASA authorization strongly endorses the future of American space exploration while getting the maximum benefit from the taxpayers’ investment in the Constellation system,” the Republican House aide said. “By redirecting funding within the agency into a restructured exploration program, we aim to restore credibility and put human space exploration on a sustainable path while ensuring U.S. access to the international space station and developing the systems necessary to meet the nation’s space exploration goals beyond low Earth orbit.”

The House Appropriations commerce, justice, science subcommittee, which oversees NASA spending, voted June 29 to fully fund NASA’s $19 billion budget request for 2011, but fenced off most of the $4.2 billion allocated for manned space exploration pending enactment of a NASA authorization bill.

The Senate Appropriations commerce, justice, science subcommittee is expected to mark up its version of the spending bill July 22. In a July 15 statement, Sen. Barbara Mikulski (D-Md.), who chairs the subcommittee, endorsed the Senate NASA authorization bill as a “solid compromise” for NASA’s human spaceflight program.