With space shuttles still launching and landing, NASA isn't keen to talk about what will happen to the iconic vehicles after they're retired.

But the competition among institutions to land a space shuttle for public display is heating up.

Last December, NASA issued a “request for information” to educational institutions, science museums and other organizations about their interest in acquiring a space shuttle. The space agency estimated it would cost about $42 million to prepare the vehicle and deliver it via a modified 747 Boeing aircraft carrier.

About 20 institutions — including a group of bidders led by Space Center Houston — responded. Since then, however, the space agency has been mum.

“We're still in a holding pattern,” said Robert Pearlman, editor of collectSPACE.com, a Web site for space history enthusiasts. “I don't think anyone in the program really wants to talk about retiring the orbiters while they're still flying them.”

With the recent safe return of space shuttle Atlantis to Kennedy Space Center, NASA now has five shuttle missions scheduled during the next year before it retires the vehicles.

The retirement date could be extended by President Barack Obama, who is expected to decide on the future of NASA's human spaceflight program during the next few months, but the shuttle's end is coming.

As part of NASA's conditions on receiving a shuttle, institutions must promise to display the vehicle indoors and commit to ongoing costs for its upkeep and care.

It will take time to raise funds to acquire the shuttle and prepare a facility in which to house it, but so far NASA headquarters in Washington has not indicated when it will make a decision.

“NASA's primary focus is to ensure that the space shuttle safely and successfully completes its mission — finishing the assembly of the International Space Station by the end 2010,” said NASA spokesman John Yembrick. “It is premature to speculate on when a final decision will be made.”

The Smithsonian's National Air and Space Museum is guaranteed one of the vehicles. The institution already has space shuttle Enterprise — which was used as a test vehicle in atmospheric flights but never flew in space — on display at its Udvar-Hazy Center in Chantilly, Va.

Discovery is Smithsonian's

NASA has confirmed that it will give the Smithsonian space shuttle Discovery, which the institution prizes for its role as the return-to-flight orbiter after both the Challenger and Columbia tragedies as well as its role in launching the Hubble Space Telescope.

That leaves Atlantis and Endeavour as the two remaining orbiters that have flown in space. And once it receives Discovery, Pearlman said the Smithsonian is likely to loan out Enterprise to another institution.

Pearlman said Kennedy Space Center — where the shuttles are launched from and serviced — seems a highly likely choice given that transporting the vehicle there would be no problem.

And he believes Houston has a very good chance as well, given its role as the space shuttle program's headquarters, home of mission control and the place where most astronauts live.

“I actually think that as long as we can raise the money to assure there will be a facility and support it, I think Johnson has a terrific chance of getting it,” Pearlman said.

The 20 bids came from a varied group of institutions around the country, from Evergreen Aviation & Space Museum in Oregon to the Tulsa Air and Space Museum in Oklahoma.

The 20 bids came from a varied group of institutions around the country, from Evergreen Aviation & Space Museum in Oregon to the Tulsa Air and Space Museum in Oklahoma.

Houston's bid is led by Space Center Houston, which wants to house the vehicle on its property adjacent to Johnson Space Center, said the center's chief executive officer, Richard E. Allen Jr.

“Space Center Houston is working along with Bay Area Houston Economic Partnership and other partners in Houston and the state because we think it's going to take a broad-reaching effort to make it happen,” he said.

“You have to raise all the money to prepare a shuttle, and you also have to raise the cost for a building. Any time you're trying to raise money in those amounts, it's a big undertaking.”

eric.berger@chron.com