In outer space, as everyone knows, there’s no up or down. In space politics, there’s no left or right. It’s an ideologically unpredictable and non-linear universe, one that happens to be, at the moment, in a state of flux.

Consider that, as the space shuttle retires, a Democratic president wants the private sector to take over what used to be a Big Government responsibility — the job of ferrying astronauts to low Earth orbit. President Obama’s policy shift, announced in 2010, meant the cancellation of a government-owned rocket, the Ares 1. That move drew resistance from conservative Republicans such as Sen. Kay Bailey Hutchison of Texas and Sen. Richard C. Shelby of Alabama.

Some Democrats also chafed at the administration’s policy pivot. What these Republicans and Democrats have in common is that they come from states where aerospace firms have benefited from traditional NASA contracts.

“Space has rarely been a partisan issue,” said Scott Pace, director of the Space Policy Institute at George Washington University.

Although space policy has a bipartisan foundation, it’s in a moment of painful transition. The final shuttle flight occurs amid protest from former astronauts and retired NASA managers who think the Obama administration is letting the U.S. space program slide into disarray.

NASA’s top officials note that, in ending the shuttle program, NASA is carrying through on a decision made by the George W. Bush administration. The shuttle’s retirement creates a gap in human spaceflight capability — a period in which American astronauts will have to buy tickets on Russian rockets to reach the international space station — but the space community has known for years that there would be a gap of some duration. (Obama’s critics say he’s lengthened it rather than narrowed it.)

A commercial rocket capable of putting astronauts in orbit could be ready by the middle of this decade. The only sure-fire way to eliminate the gap would be to keep flying the shuttle. But there’s a general consensus that the shuttle has accomplished its mission now that the U.S. portion of the space station is complete. The shuttle costs billions of dollars a year to operate and has eaten up the bulk of the human spaceflight budget for decades. Only by ending the shuttle program could NASA free up money for new rockets and a more ambitious program of deep-space exploration.

The Constellation program, with the goal of a return to the moon, was the Bush administration’s effort to create a follow-up to the shuttle, but it did not survive for long after the change in administrations. Constellation’s funding never matched its aspirations, according to a presidential review committee. President Obama nixed the moon mission and has endorsed sending astronauts to a near-Earth asteroid by 2025.

NASA could announce any day the design of the new, government-owned, heavy-lift rocket that would make such deep-space exploration possible. Congress is impatient as it waits for NASA’s plans. Senators from both parties went so far recently as to threaten the agency with a subpoena if it didn’t hand over documents showing what it’s been up to regarding the new rocket.

Hutchison groused last week, “Congress has given NASA the blueprint to proceed and it is past time they move forward with development.”

NASA handed over the documents. The political kerfuffle demonstrated that Congress views itself as a major architect of space policy. When Congress passed the NASA authorization bill last year, it insisted that the Obama administration speed up development of the new rocket that would be capable of deep-space exploration.

Space policy has many authors, even within the administration. NASA leads the effort, but strategic decisions have to be vetted by the White House’s Office of Science and Technology Policy. The most influential player in the administration at the moment may be the Office of Management and Budget, which has been reviewing the heavy-lift rocket plans and must sign off on any massive expenditure at a time when budgets are squeezed.

“It’s OMB that’s holding this thing up,” complained Sen. Bill Nelson (D-Fla.). “You have bureaucrats over there who think they run the space program.”

The corporate aerospace community represents a powerful force in the shaping of space policy. The Pentagon has input as well. One reason it is hard to pivot dramatically in civilian space policy is that decisions can have national security implications.

“This nation’s leadership in human spaceflight is a matter of our national strategic posture,” said Mike Griffin, who served as NASA administrator under Bush. “Now we’re leaving that to the vagaries of the commercial marketplace.”

NASA Administrator Charles Bolden addressed that issue in a speech Friday at the National Press Club: “We have to get out of the business of owning and operating low Earth orbit transportation systems and hand that off to the private sector, with sufficient oversight to ensure the safety of our astronauts.”

Newton and Einstein also have something to say about what happens with space policy. Any strategy is limited by physics. The most enticing target for exploration, Mars, would require a roughly six-month journey one-way with conventional chemical rockets.

Merely getting to orbit requires that spaceships climb a steep gravity hill. They need to reach speeds of about 17,500 miles per hour to reach orbital velocity.

NASA has contemplated a manned trip to the little Martian moon Phobos rather than to the more interesting destination of the Martian surface. That’s because Phobos has very little gravity. A spaceship would essentially dock with Phobos as though it were a space station. That’s much easier than trying to descend safely the gravity hill of Mars and then trying to climb back up the hill before rocketing home.