WASHINGTON -- House and Senate negotiators still expect to resolve their differences over a bill that would establish regulations for suborbital launch firms that plan to carry paying passengers into space. But with U.S. lawmakers slated to leave town the first week of October, proponents say time is running out to enact the legislation this year.

James Muncy, an aerospace consultant lobbying for the bill, said the Commercial Space Launch Amendments Act (H.R. 3752) still has a chance to become law this year, provided the Senate Commerce Committee moves on it in the days ahead. He said the House and Senate are pre-conferencing the bill now so that it can sail through to final passage without taking up precious floor time when so little remains before Congress adjourns for the year.

Muncy said the legislation would help suborbital launch firms, some of which are vying for the $10 million Ansari X-Prize, get their businesses off the ground.

"The legislation is the difference between winning a prize and being able to operate for revenue and build a real industry," said Muncy.

After sailing through the House of Representatives in March on a vote of 402-1, the Commercial Space Launch Amendments Act of 2004 bogged down in the Senate this spring when Sen. James Inhofe (R-Okla.) put a hold on the bill after constituents complained it might not cover a reusable launcher being built by Oklahoma City-based Rocketplane Limited.

The concern was due to the bill's definition of a suborbital rocket, which Rocketplane officials worried would allow the Federal Aviation Agency (FAA) to treat its proposed reusable launcher as a commercial aircraft. Rocketplane's vehicle would take off from a runway under conventional turbo jet thrust, but rely on rocket engines to reach space.

Inhofe lifted his hold in late July after negotiators agreed to tweak the definition to satisfy Rocketplane's concerns.

House and Senate negotiators, meanwhile, are still trying to come to closure on a definition of suborbital rocket that is agreeable to everyone, including the FAA, and iron out difference over the bill's liability provisions.

The bill passed by the House bill would require passengers to sign away their right to sue before climbing aboard a suborbital launcher, a provision proponents say is necessary while the suborbital tourism trade is still in its infancy.

Opponents would like to see the liability cross waiver provision dropped from the bill.

House Science Committee spokesman Joe Pouliot said Sept. 16 that discussions were still under way with the Senate Commerce Committee over an unspecified number of proposed changes to the Commercial Space Launch Amendments Act of 2004 (H.R. 3752) but that the staffers involved in the discussions were hopeful the bill could still be enacted before Congress adjourns.

A Senate Commerce Committee staffer agreed that enactment is still possible this year. "We are in discussion and want to see this to happen," the Senate staffer said. "We're working on it but we are not there yet."

Muncy, meanwhile, would not predict the bill's prospects should it be tabled until next year.

"The Congress has spent almost a year and a half considering this issue and the House has decided, and the Senate seems inclined to decide, that this is an important new industry," Muncy said. "We need to provide the regularity clarity and the promotional mandate at the FAA so they can help make this industry happen as quickly as possible."

The House and Senate held a joint hearing on the issues confronting the manned suborbital launch industry in July 2003. The Senate Commerce Committee had passed a one-page bill, the Commercial Space Transportation Act of 2003 (S.1260) the previous month that would extend indemnification for commercial satellite launchers and direct the Department of Transportation to submit a report on the need for a distinct regulatory regime for piloted suborbital launchers.

After the July 2003 hearing, House Science Committee staffers promised to spend the rest of the summer drafting a more comprehensive bill based on the input from suborbital rocket companies, the FAA and other experts said.

Rep. Dana Rohrabacher (R-Calif.), the chairman of the House Science space and aeronautics subcommittee, introduced the Commercial Space Act of 2003 (H.R. 3245) in October 2003 and held a hearing to gather more testimony in support of the measure. Congress adjourned for the year before the bill could clear committee.

During the winter break, the House Science Committee brought suborbital rocket companies and potential investors together with FAA regulators in December to the legislation. In February, Rohrabacher introduced a revised bill, H.R. 3752, that sailed through the House Science Committee and passed the House in March with nearly unanimous approval.

Congressional sources said that provided House and Senate negotiators work on their differences in the next two weeks, the bill could be teed up for final passage without requiring a floor vote in either chamber of Congress.