A dozen astronauts and cosmonauts from four countries face delays in their return to Earth or launchings to the International Space Station (ISS) before year-end, following the failure of a Russian Soyuz-U rocket to push 5,900 lb. of supplies to orbit Aug. 24.

Loss of the Progress 44P unpiloted cargo carrier comes as NASA and its ISS partners await the development of commercial crew vehicles to backstop the Soyuz capsules that are the only route to space for station crews now that the space shuttle has stopped flying.

NASA added the shuttle's final mission to stock the station with enough supplies to buy the potential commercial providers an extra year to complete development and begin delivering cargo. The unexpected failure of the highly reliable Russian launcher highlights the importance of the commercial cargo and crew developments for station operations.

The latest of the venerable freighters crashed into the sparsely populated Altai Republic after a picture-perfect liftoff from the Baikonur Cosmodrome in neighboring Kazakhstan, jeopardizing the transportation of multinational crews to and from the orbiting science laboratory as well as the research potential.

Officials quickly dismissed the significance of the lost propellant, water, compressed air and other consumables stuffed into the space freighter for the first supply mission launched to the six-person orbiting science lab since NASA's long-running shuttle program entered retirement in July.

Rather, it was the third stage of the Soyuz-U rocket, which abruptly shut down moments after igniting, that has them concerned. Other than a higher thrust level, the errant propulsion source is almost identical to the third stage of the Soyuz-FG rocket assigned to launch U.S., Russian and other crew to the NASA-managed 15-nation orbital outpost.

“Obviously, this has implications for the vehicle on orbit,” says NASA's Mike Suffredini, the ISS program manager, who waited anxiously in his office at the Johnson Space Center for an email message revealing the outcome of the 9 a.m. EDT launching from Baikonur.

NASA's final shuttle flight, the 13-day STS-135 station resupply mission, touched down on July 21, after its crew fortified the station with enough food, spare parts and other goods to sustain six-person crews through 2012—assuming the success of scheduled Progress deliveries, as well as contributions from Europe's Automated Transfer Vehicle and Japan's unmanned HII Transfer Vehicle.

The strategy was intended to sustain a large crew as NASA transitions from shuttle operations to cargo deliveries by emerging commercial cargo carriers Space Exploration Technologies Corp. (SpaceX) and Orbital Sciences Corp. SpaceX is aiming for a mid-December launch of the Falcon 9/Dragon on the first attempt by a commercial supplier to demonstrate station-berthing operations.

Scheduled to arrive at its Cape Canaveral launch site on Sept. 17, the Dragon capsule in that test could carry up to 1,760 lb. of cargo on the demonstration mission. Suffredini says that cargo will be goods not considered critical to the station's future. Orbital, whose Cygnus capsule arrived at the Wallops Island, Va., launch facility Aug. 24, is to follow in 2012, as a prelude to regular U.S. commercial resupply missions the following year. One issue stalling the SpaceX launch is the company's plan to piggyback a pair of Orbcomm low-Earth-orbit communications satellites on the launch, which requires additional safety reviews by NASA and the FAA's commercial-space office (AW&ST Aug. 15, p. 34).

“I would like to see at least one commercial flight to the ISS—just to make sure the system will be there in the 2013 time frame,” says Suffredini. “Logistically, we did not require it.”

Though well-stocked at the moment, a lengthy Soyuz recovery or a miscalculation in the strength of the post-shuttle supply chain could force a reduction to three crew, thwarting efforts to ramp up scientific research and technology demonstrations after nearly 13 years of station assembly and outfitting.

The commercial crew transportation services NASA is attempting to nurture are not expected to begin operations until 2015-16. That will depend on adequate congressional funding for the nearly three-year-old Commercial Crew Development (CCDev) effort, which is separate from the Commercial Orbital Transportation Services (COTS) program that helped fund the cargo craft.

Phil MacAlister, who runs the CCDev effort at NASA headquarters, says there is “no immediate action” planned in the commercial crew program as a result of the launch failure. “We hope this is just a short-term disruption to the crew and cargo supply chain for the ISS,” he says.

The Soyuz-U hurtled toward orbit for 325 sec. before the flight control system called for a premature shutdown of the third stage. Russia's Mission Control filled in the station crew on the unfolding saga after attempting in vain to re-establish contact with the booster and independently with the Progress in case the freighter had managed to separate and reach orbit.

“We will try to figure out what happened,” an official in the Moscow control center promised station commander Andrey Borisenko of Russia and his five crewmates. As the mishap unfolded, Borisenko, fellow Russian Alexander Samokutyaev and American Ron Garan were scheduled to depart the station in their Soyuz TMA-21 capsule and descend to Earth on Sept. 8, after 156 days in orbit.

“Obviously, I have mixed feelings,” Garan says. “Whatever decision would be best for the program we're fully supportive of.”

Russian space agency Roscosmos launched an investigation into the cause of the failure, and Prime Minister Vladimir Putin ordered a broad review of procedures and quality control in the space industry. The NASA International Space Station Mission Management Team, which includes Roscomos, is addressing the impact of the Progress 44 loss on station operations and could decide as soon as Sept. 2 on the timing of the next crew return and subsequent rotations.

Russians Anatoly Ivanishin and Anton Shkaplerov and American Dan Burbank were scheduled to lift off aboard the Soyuz-03M on Sept. 21 for a six-month tour of duty on the station. American Mike Fossum, Russian Sergei Volkov and Japan's Satoshi Furukawa were scheduled to depart the station on the Soyuz-O2M on Nov. 16, descending to Earth after 162 days in orbit. They are to be replaced by Russian Oleg Kononenko, American Don Pettit and Andre Kuipers of the Netherlands, with a launch aboard the Soyuz-O4M on Nov. 29.

Russia's Soyuz capsules are equipped to remain in orbit for up to 210 days, affording station managers nearly two months of leeway in returning the TMA-21 and O2M crews to Earth and maintain station staffing at six for a longer period. The limit is based on deterioration of propellant and propulsion hardware.

Prior to the mishap, Russia planned to launch the Progress 45 and 46 missions in late October and December. If a resolution to the Progress 44 loss is reached quickly, the late October follow-on supply mission could be advanced, Suffredini says.