Of all the recent space secrets that the USAF and NASA are keeping one of the most intriguing is the X-37B that is in orbit right now. The space plane looks like a smaller version of the retired space shuttle and was lofted into orbit back in March for a 9-month mission. Exactly what the mission of the X-37B is and what payload is in its cargo bay is unknown.
The spacecraft is 29-feet long and took off on the tip of an Atlas 5 rocket. All the USAF officials have said so far is that the X-37B is an orbiting experiment platform. The spacecraft is designed with wings and when it returns to earth it will use GPS to land on a runway in California. Engineers on the mission are extending the craft's stay in orbit by an undefined period.
The USAF says that the extension will allow it to get the maximum value from the mission. The orbiter itself is reusable and is clad in heat shielding materials to return the experiment payloads to earth intact. This is the second X-37 aircraft to be sent into space. The first mission landed after 224 days in space and landed safely making it the first to complete an automated landing in the US.