Private industry's ability to handle resupply missions to the International Space Station will be tested once again Wednesday when a second U.S. company launches its own rocket and spacecraft toward the ISS.
Sending a cargo-filled spacecraft to the orbiting outpost is a complicated venture that has only been accomplished by a handful of governments and the California-based company SpaceX.
That list might expand after the Virginia-based company Orbital Sciences launches its Cygnus spacecraft atop its Antares rocket from the Mid-Atlantic Regional Spaceport at NASA's Wallops Flight Facility in Virginia.
The plan is for Cygnus to deliver about 700 kilograms of cargo, including food and clothing, to the station's crew.
This demonstration mission is the final part of NASA's Commercial Orbital Transportation Services program, in which the U.S. space agency acts as a lead investor in the private sector's development of commercial space transportation.
Alan Lindenmoyer, manager of NASA's Commercial Crew and Cargo program, says competition and redundancy are beneficial to the space agency.
"You never want to be put in a situation where if there's a problem with one of the suppliers that you don't have the ability to continue your resupply chain to the space station," he said. "So we intentionally designed our program to have at least two companies, certainly in the development and demonstration phase, and then we were fortunate enough to be able to award contracts to both of them as well."
The Cygnus spacecraft is expected to reach the station in about four days, and several of its systems will be tested during that period. If all goes as planned, it will dock with the station this Sunday.
The governments of Russia, Europe and Japan also have cargo craft that can reach the orbiting lab. The U.S. government has not had a vehicle capable of traveling to the space station since it retired its space shuttle fleet in 2011.
NASA's Lindenmoyer says it is critical for the space agency to be able to rely on private industry to ferry cargo.
"This is allowing NASA to focus on the more challenging efforts of continuing human exploration deeper into space," Lindenmoyer told reporters during a pre-launch briefing.
The U.S. space agency is working on the next generation of spacecraft that could travel to an asteroid or to Mars.