NASA tests a new crew launch vehicle in late 2009. Photo Credit/NASA

After months of gridlock, the House and Senate have engaged with the White House in a recent flurry of legislative activities intended to produce an agreement on the future of NASA-led space exploration.

However, key differences remain, especially over the much larger role for commercial space transportation services favored by the Obama Administration.

Until President Obama receives and signs legislation agreed to by both houses of Congress spelling out NASA’s priorities and appropriating funds, the space agency can only plan for change.

The 2011 fiscal year, which begins Oct. 1, marks the earliest point at which NASA could move ahead on a new course, whether it includes President Obama’s desired cancellation of the previous administration’s Constellation back-to-the-moon program; a Congressional initiative calling on NASA to accelerate the development of a heavy lift rocket and crew capsule for deep space exploration missions;

The extension of International Space Station operations to 2020; the addition of one more shuttle mission in mid-2011; or embarking on the president’s near $6 billion, five-year initiative to foster a commercial launch industry for the transportation of astronauts to the Space Station.

The House and Senate will likely have to work out their differences in conference committees, extending the process.  Then, if the House prevails on a commercial crew transportation provision that totals just $450 million in direct payments, loans and loan guarantees over the next three years, would the president sign the bill?

Here’s a brief summary of the most recent developments, which find all sides in agreement on a few key issues. Those include increasing NASA’s budget to $19 billion in 2011 to establish a foundation for a new era of human deep space exploration; extending space station operations from 2015 to 2020; and the addition of a mid-2011 mission to the two remaining shuttle flights scheduled for early November and late February.

There are important distinctions as well.

On Thursday, the House Science and Technology Committee approved a bi-partisan three-year policy blueprint for NASA that could go to the full House for consideration as soon as next week, according to the U. S. Rep. Bart Gordon, the panel’s chairman. The measure backs NASA’s development of an Orion-like capsule and a rocket that could reach the space station with astronauts by 2016. Accelerated work on a heavy lift rocket would pave the way to future deep space missions to destinations like the moon, near-Earth asteroids and Mars.

Also on Thursday, the Senate Appropriations Committee approved NASA’s $19 billion top line, which funds a restructuring of the agency’s human space flight program. The bill puts $3 billion behind an effort to accelerate the NASA development of a heavy lift rocket and new crew transportation capsule suited for deep space missions by the end of 2016.

The White House favors research and technology investments until 2015 before settling on a heavy lift strategy. Constellation’s Orion crew capsule was re-assigned a new role, space station life boat, by the administration.  Humans would head to an asteroid by 2025 and perhaps circle Mars a decade later under the president’s strategy, a much more drawn out timeline than the Senate and House envision.

The full Appropriations Committee acted just one day after the Senate’s Commerce, Justice and Science Subcommittee on Appropriations acted on the NASA measure.

On July 15, the Senate Commerce, Science and Transportation Committee adopted a bi-partisan, three-year authorization measure that signaled a break in a policy log jam over NASA’s future that dates back to early 2010. The measure introduced the prospect of accelerated work on a heavy lift rocket and a crew capsule for deep space missions by 2016. It proposed the addition of another shuttle mission.

The same Senate panel suggested a slow down in the White House commercial space initiative. It pledges $1.6 billion over the next three years to the fostering of commercial crew and cargo delivery services for the space station — $1.3 billion of the total for crew transportation.

The current flurry of legislative activity got under way on June 29, when the House Commerce, Justice and Science Subcommittee on Appropriations approved a $19 billion NASA spending measure.

However, the bill stopped short of appropriating anything for human space flight. Chairman Alan Mullohan said the panel would take no further action on a House spending bill until President Obama signs a House and Senate backed NASA Authorization bill.

The decision represents a lingering road block to the agency’s human exploration plans.