Bad weather at Cape Canaveral has postponed the launch of the military's robotic space plane on a second secret mission, Space.com reports.

Another attempt will be made Saturday, but there's a 70% chance of more bad weather.

The Boeing-built X-37B Orbital Test Vehicle 2, which resembles a stubby space shuttle, missed two launch windows this afternoon, the last ending around 5:30 p.m. ET.

The Air Force's other X-37B vehicle, known as OTV-1, was launched in April 2010 and landed on its own in December at Vandenberg Air Force Base, near Santa Barbara, Calif.