U.S. spaceflight managers are mapping a course for the International Space Station’s coming decade that they hope will “seed” a high-value commercial research economy in low Earth orbit, but first they must navigate some treacherous passages on Capitol Hill.

NASA has scheduled the STS-135 mission on the shuttle Atlantis for June 28, and Congress has authorized the flight. Funding it is another question, and with fiscal conservatives pushing for deep spending cuts for the remainder of fiscal 2011, that question remains open.

The federal government is funded only through March 18, giving lawmakers a little more time to decide spending levels through the end of September. While anything could happen in Congress before the deadline, NASA is acting on the assumption that it will get enough money—estimated at $600 million—to fly Atlantis on what will be the final space shuttle mission ever. Otherwise, that distinction will go to the STS-134 crew that will fly on April 19, while Atlantis waits at the ready as a rescue vehicle.

“If you take drastic action, and significantly reduce the amount of money that I get whenever we get a 2011 budget, then it could change things,” Administrator Charles Bolden told the House Science Committee March 2. “But right now, I anticipate that reasonable people can disagree and that the Congress is going to come to agreements that will not cripple NASA and the rest of the nation, and that we will fly STS-135.”

The mission will buy about a year of wiggle room for the commercial vehicles NASA hopes will take over ISS cargo-delivery duties. William Gerstenmaier, the associate administrator for space operations, says Atlantis can deliver enough cargo—“food, water, some components, . . . a lot of little dogs and cats, nothing special—to sustain a six-person station crew and keep them working at full tilt through 2012, even if there are no commercial cargo deliveries.”

Without Atlantis’s flight, NASA and its partners run the risk of slowing research or even cutting back on the crew if Space Exploration Technologies Inc. (SpaceX) and Orbital Sciences Corp. (OSC) cannot make their cargo vehicles work. That would eat into the utilization time NASA and its partners have built toward for the past 10 years.

“The commercial cargo providers are both doing pretty well,” Gerstenmaier says, noting that SpaceX hopes to fly as early as this summer, while OSC will fly by the end of the year if its new launch facilities on Wallops Island, Va., are ready.

“In 2012, we really need to get services established,” he says. “If there’s a delay in the startup of those commercial services, [STS-135] allows us essentially to make it through all of 2012 without a major impact to research on station or a major impact to crew size.”

Longer term, that year is critically important to NASA, because the space station is where the U.S. human spaceflight program will occur for the foreseeable future. House science panel members criticized Bolden over the 2012 budget request, which they said “flips” congressional priorities embodied in the 2010 NASA Authorization Act, giving more emphasis to evolving commercial cargo services into a commercial crew-delivery capability and less to the heavy-lift crew launcher and Orion-based crew capsule that Congress wants (AW&ST Feb. 21, p. 20, 35).

“Commercial crew was not ignored, but to be perfectly clear, it was not—and is not—Congress’s first priority,” says Rep. Ralph Hall (R-Texas), the committee chairman. “Our first priority is to continue with the development of the Space Launch System and Multi-Purpose Crew Vehicle.”

Bolden defends the new budget as the best way to support the ISS with “American-made rockets” in the near term, while developing the heavy-lifter and its capsule to explore beyond low Earth orbit. And for the near term, he says, “the International Space Station is the anchor for all future exploration; that’s our Moon right now.”

Gerstenmaier, who has managed ISS assembly and the wind-down in shuttle operations, likely will oversee the next step in station utilization as head of the new NASA mission directorate to be created from the merger this spring of space operations and exploration systems. Given the research capabilities of the almost-complete orbiting facility, operations there promise to be as intense, in their own way, as past U.S. human spaceflight.

NASA already is conducting pharmaceutical research on the station in association with commercial partners, taking advantage of the way microbes behave in microgravity to accelerate development of vaccines for diseases and infections on Earth (AW&ST Sept. 21, 2009, p. 28). Researchers at the U.S. National Institutes of Health are laying plans to use known effects of prolonged human exposure to microgravity—bone loss and immune system suppression—to develop medications for treating ailments of the elderly.

On the station, Gerstenmaier says, researchers will have plenty of time to change course if a particular line of inquiry does not bear fruit, just as they would do in a terrestrial lab. That has not been possible on the shuttle, or generally speaking on the station during the assembly phase.

The station itself is a huge engineering laboratory that has taught volumes about building and operating large structures in space, and it will have other uses as an engineering testbed in the years ahead. If it flies, STS-135 will deliver a satellite mock-up that can be used to develop technologies and techniques for servicing and refueling spacecraft robotically, using the station’s Canadian-built Dextre robot.

“We’ll be able to use Dextre to go take a satellite interface that’s mocked up on this box, that looks just like the outside of a satellite, and actually remove the thermal blankets and remove screws and go into the refueling coupling and actually hook up a coupling and transfer some ethylene glycol from one tank to the other tank,” Gerstenmaier says.

Delivery of the testbed will be easiest in the shuttle payload bay, Gerstenmaier says, adding that the mock-up can be used to test additional refueling configurations, if they become available.

NASA is in talks with Ad Astra Rocket Co. to fly its prototype 200-kw variable specific impulse magnetoplasma rocket (Vasimr) engine on the station’s Z1 truss in 2014 (AW&ST Feb. 7, p. 56). Other propulsion tests are in the works. “We may look at some new nontoxic propellant systems on station,” Gerstenmaier says. “We’ve talked about some ion engines.”

Also under consideration is using the entire station and its six-person crew as an analog for a deep-space human exploration vehicle en route to Mars. An internal team is studying the feasibility and value of such an exercise in the summer of 2012.

“We might start with a small window, like a 30-day window, with actual time delays with what we’d expect with a Martian communications system,” Gerstenmaier says. “We may freeze our consumables on station, in the sense of saying that we’ve started our voyage to Mars, and see how well we do in our predictions.”

While the station is essentially complete—except for the “facility level” satellite-servicing testbed and a Russian research module—Gerstenmaier says NASA is in discussions with Bigelow Aerospace about using one of its inflatable habitats as a combination orbital testbed/storage space on the ISS. By attaching and inflating a unit on the station, Bigelow could gain the experience it needs to human-rate its habitats, and NASA could gain flight-test experience with the noise, radiation and other habitability issues of an inflatable structure that it could also use for on-orbit storage.

Ultimately, assets like the free-flying habitats Bigelow is developing could be commercial homes for the sort of research work initially conducted on the station. Gerstenmaier says right now it appears that the low Earth orbit environment is more valuable for research than for manufacturing.

“We use station as kind of the test facility, the research facility to see if there is enough of a market in this area for somebody to have a unique space station dedicated to this particular commercial activity,” he says. “So ISS could actually be kind of the seed ground that spins off a new economy in space for the niche kind of research facilities.”