America's presence in space took another leap backward when a Russian rocket bound for the International Space Station went down shortly after launch.

The unmanned vehicle, carrying 2 1/2 tons of supplies, broke up and crashed back to Earth last week. It was the first mission to the ISS since the United States retired its space shuttle program last month.

"This is exactly why I offered legislation to keep the shuttle flying," said U.S. Rep. Bill Posey, R-Rockledge. "With the Russians, we have no backup plan."

The Russian space agency has suspended further flights until it determines what went wrong on the Progress 44 supply vehicle. The accident was the latest in a series of Russian launch failures over the past 10 months.

According to Space.com, on Aug. 18, a Proton rocket failed to place a $300 million communications satellite in the proper orbit.

On Feb. 1, a Russian Rokot launch vehicle failed to deliver an Earth-observing satellite to the proper orbit. And on Dec. 5, 2010, three pricey navigation satellites lofted by a Proton crashed into the Pacific Ocean.

That track record cannot be comforting for U.S. astronauts, who are being charged $50 million per seat for Soyuz rocket rides to the ISS.

"This failure should be a cause of grave concern, and a moment of re-examination of America’s space strategy," U.S. Rep. Dana Rohrabacher, R-Calif., said in a statement. "The most responsible course of action for the United States is to dramatically accelerate the commercial crew systems already under development."

Rohrabacher, a senior member of the House Committee on Science, Space and Technology, said, "NASA needs to conduct an investigation before another Soyuz spacecraft with new ISS crew members can be launched."

Posey, who represents Florida's Space Coast, said the Progress failure highlights already-growing concerns about national security. He noted that the space station recently dodged debris from a Chinese satellite.

"Instead of letting their [disabled] satellite burn up in the atmosphere, the Chinese took target practice on it. What's next?" Posey said.

Russian rockets are being used to supply the ISS while a pair of emerging U.S. commercial suppliers, SpaceX and Orbital Sciences, ramp up their programs, according to the Coalition for Space Exploration.

The first SpaceX attempt to launch and berth an uncrewed Dragon supply capsule with the station is tentatively scheduled for December. An inaugural Orbital Sciences flight is planned for 2012, CSE reported.

"The failure of the Soyuz booster carrying the Progress cargo spacecraft highlights the need for a mixed U.S. and Russian space fleet," SpaceX communications vice president Bobby Block told Sunshine State News.

"The International Space Station right now is 100 percent dependent on a single Russian rocket for delivery of crew to the station and a large portion of the cargo, too. The sooner we come online with a U.S. commercial crew capability, the sooner this window of ISS vulnerability will end," Block said.

A three-man U.S. and Russian station crew aboard the ISS is scheduled to return to Earth Sept. 8, after 156 days in orbit. A U.S.-Russian replacement crew is ticketed to launch aboard a Soyuz spacecraft Sept. 21.

Three U.S., Russian and Japanese astronauts also at the space station are slated to return Nov. 16, after 162 days.

The Soyuz capsules were designed to remain docked to the station for up to 210 days, making lengthy extensions for the return of all six astronauts currently on the station possible, CSE reported.

Space policy expert John Logsdon said it's too soon to hit the panic button.

The professor emeritus at George Washington University told Space.com that last week's crash was the first failure for a Progress vehicle after 43 successful missions. And he noted that the Soyuz-FG has a perfect record -- more than 20 successful launches since its maiden flight in 2001.