WASHINGTON — As NASA awaits a presidential decision on the future of its human spaceflight program, the agency is pushing ahead with plans to award $50 million in economic stimulus money meant to seed development of commercial crew transportation services.

NASA contacted at least six companies Nov. 6, inviting Ball Aerospace & Technologies, Boeing Co., Paragon Space Development Corp., Sierra Nevada Corp., Space Exploration Technologies (SpaceX) and United Launch Alliance to discuss the Commercial Crew Development, or CCDev, proposals each submitted in September.

Industry sources say that while no single company is expected to receive the entire pot of money, it remains unclear how NASA will divide the $50 million for commercial crew initiatives the agency received under the American Recovery and Reinvestment Act the U.S. Congress passed in February to jumpstart the stalled economy.

Boeing announced in September it was seeking CCDev money to accelerate development of a crew transportation system that company spokesman Ed Memi said would incorporate a crew capsule adaptable to launch atop multiple rockets. The proposed project, which includes a teaming arrangement with North Las Vegas, Nev.-based Bigelow Aerospace, draws on Boeing’s experience with proven human-rated spacecraft.

In addition, Boeing partnered with three other teams that submitted separate bids. Memi declined to comment on the status of any of the company’s proposals.

Sparks, Nev.-based Sierra Nevada’s plan involves a runway-landing, lifting-body vehicle called Dream Chaser that the company has been working on for several years. The six-passenger vehicle is based on NASA’s HL-20 concept from the early 1990s.

Ball Aerospace would not share details of its proposal, but spokeswoman Roz Brown confirmed the company submitted a CCDev bid.

Industry sources said United Launch Alliance (ULA), the Denver-based Boeing-Lockheed Martin joint venture that builds and operates the Atlas 5 and Delta family of rockets, supported multiple CCDev proposals and bid as a prime on a proposal to develop emergency detection system technologies key to human-rating its U.S. Air Force Evolved Expendable Launch Vehicles. ULA spokeswoman Julie Andrews declined comment.

SpaceX’s proposal, industry sources said, involves development of a launch escape system the company needs in order to transform its reusable Dragon cargo capsule into a crewed vehicle. SpaceX spokeswoman Emily Shanklin declined comment.

Tucson, Ariz.-based Paragon Space Development Corp.’s chief strategist, Lance Bush, said his company proposed a yearlong effort to build and demonstrate an air revitalization system that could be incorporated into any contemplated commercial space capsule, including Dragon or a crewed variant of the Cygnus vehicle proposed by Dulles, Va.-based Orbital Sciences Corp.

“We’ve been doing a lot of innovation in this area since our inception, and with NASA as one of our customers,” Bush said Nov. 9.

NASA officials declined to say how many CCDev proposals the agency received in September or how many are still under consideration.

NASA spokeswoman Stephanie Schierholz said Nov. 9 the agency plans to announce contract awards this month. Industry sources paying close attention to CCDev, however, said they do not expect an announcement until mid-December, a date by which these sources expect the administration of President Barack Obama will have made some internal decisions based on the finding of the Review of U.S. Human Space Flight Plans Committee.

The committee, led by former Lockheed Martin chief Norm Augustine, found the agency’s current plan to replace the space shuttle with rockets and spacecraft optimized for the Moon is incompatible with the agency’s budget. The committee’s report, issued Oct. 22, urged the administration to consider relying on commercial ventures to transport cargo and astronauts to low Earth orbit.

One NASA official said the agency is conducting an internal review of the Augustine panel’s heavy-lift options to help inform the president’s decision. NASA’s Marshall Space Flight Center in Huntsville, Ala., is leading the effort, the findings of which are to be briefed to senior NASA officials in early December, the NASA official said.

With internal White House and NASA deliberations on the agency’s 2011 budget request expected to wind down in December, it is conceivable that Obama will have settled on a path ahead at that time. Some industry sources with close ties to the administration insist key decisions have already been made. Regardless, it remains unclear whether Obama will announce his choice before the end of the year or wait until the 2011 budget submission to Congress in February, as some administration officials have suggested. One industry source close to the administration predicted the White House would make a low-key announcement during the holiday season.

“The White House is concerned a big announcement for NASA might be viewed as Obama taking his eye off the ball,” the industry source said, referring to the president’s two top priorities this year — health care reform and Afghanistan.

Meanwhile, companies with a vested interest in spaceflight will be scrutinizing NASA’s forthcoming CCDev awards for hints about the direction the Obama administration intends to take.

“The CCDev results will be the canary in the coal mine,” said Mike Gold, chief counsel for Bigelow Aerospace and head of its Washington operations division here. “Either NASA will select politically benign systems and subsystems relevant to any kind of spacecraft, or they could make selections that directly lend themselves to commercial crew. If the projects and companies that have been reported as finalists in the media are accurate, then I believe it is definitely the latter.”