The U.S. Air Force on Tuesday said it may require private insurance as part of future contracts to ensure the companies that launch military satellites into orbit survive even if one of their rockets explodes and causes a long halt in launches.

General George Hyten, who heads Air Force Space Command, said the government needed a new approach to reflect the emergence of a commercial launch industry while still giving it assured access to space by at least two providers.

He also said the Air Force would need to spell out how long a launch vehicle would be grounded after an accident, and which agency would have the authority to resume launch flights.

The Air Force expects to certify privately held SpaceX, or Space Exploration Technologies, by June to compete for launches, Reuters reported.

United Launch Alliance, a joint venture of Boeing Co. and Lockheed Martin Corp., is now the sole launcher of U.S. military and spy satellites, but one of its two rockets uses the Russian RD-180 engine which is banned for national security launches after 2019.

The new initiative is a response to end U.S. reliance on the RD-180 rocket engine, Reuters reported.

ULA, SpaceX and other companies like Orbital ATK Inc, which builds smaller launch vehicles, and Aerojet Rocketdyne, which builds engines, have been awaiting the terms of the new competition, Reuters reported.

Responses to the draft request for proposals are due by May 11, with a final request to be posted 15 days later, according to the notice on a federal website late on Friday.