The Air Force's mysterious X-37B space plane is now readying for its third space mission, slated to begin in October. And perhaps not surprising for the hush-hush orbital drone, the third time into space remains as secretive as the first two.

Next month, the X-37B will blast off again aboard an Atlas 5 rocket from Cape Canaveral Air Force Station in Florida. The exact timing of the October launch is unknown and subject to change due to weather conditions, and there's no telling how long the drone will stay in orbit. "Preparations for launch at Cape Canaveral have begun," Major Tracy Bunko, an Air Force spokesperson, told Space.com.

While it'll be the third flight for the robotic space plane program as a whole, it's only the second for this particular craft. Four months ago, X-37B's second of two planes returned from its first flight and a record-breaking 469 days in orbit – more than double the first mission's total.

Will the OTV-3 try to break that record? The military, naturally, hasn't said; calls to the Air Force were not immediately returned. Nor does the public know what exactly it'll be doing once it's up there. Its mysterious mission has fueled speculation it could be a spy. China fears it could be an experimental weapons platform or a means to disable satellites.

What we do know about the X-37B is that it's a smaller, unmanned version of the now-retired space shuttle and is ostensibly used for Air Force research missions of an indeterminate nature. The manned space shuttle, we know, was retired last summer and just completed a three-day ferry flight across the United States. The X-37B is like a lighter robotic version, and can stay up for more than a year at a time – far longer than the manned shuttles ever could. The drone measures 29 feet long and 15 feet wide, weighs 11,000 pounds and is about a fourth the weight of the space shuttle, and launches into orbit on a conventional rocket but glides back down to Earth like a plane. Inside the plane is a payload bay roughly the size of a pickup truck bed. It costs around an estimated billion dollars.

The done has also received attention from secretive sources. The National Reconnaissance Office (NRO), America's secret spy satellite agency, has shown interest in using reusable launch vehicles like the X-37B to carry sensors. Right now the X-37B happens to be the only reusable space plane currently in service by the U.S. military, which narrows the NRO's options.

The Air Force is also considering a shift of the craft's landing site from Vandenberg Air Force Base in California – where the two previous X-37B flights touched down – to Kennedy Space Center near Cape Canaveral. The Space Center's Shuttle Landing Facility was used for most of the old shuttle landings, which would be a way to use leftover infrastructure and save money by leveraging "previous space shuttle investments," said Bunko.

Trying to find a way to reduce costs is crucial if the X-37B is to survive, and promoting the X-37B as an affordable replacement for the shuttle has figured prominently in statements from Boeing. There have been recurring questions as to why the Air Force needs a new reusable orbiter when contrasted with existing — and cheaper — conventional satellites. The facility, called Building 31, has been the center of a fractious labor dispute between Boeing managers and engineers.

There's also increasing competition from the private space industry pushing the Pentagon and Boeing to find cheaper alternatives to get into space. Paul Rusnock, Boeing's vice president of Government Space Systems, has said the return of the first X-37B to space will demonstrate that it's "an affordable space vehicle that can be repeatedly reused."

Which means the space plane must impress – albeit in a rather secretive way.

Update 5:00 p.m.: "We are on track to launch the third X-37B OTV mission in late October," Lt. Col. Tom McIntyre, the X-37B program manager at the Air Force Rapid Capabilities Office, tells Danger Room. The plane is designed to stay up for nine months, but "actual duration will depend on test objectives, on-orbit vehicle performance, and conditions at the landing site."

"The focus of the program –and of this upcoming mission – remains on testing vehicle capabilities and proving the utility and cost effectiveness of a reusable spacecraft," McIntyre said.

McIntyre added that the Air Force is evaluating the feasability of landing at the Kennedy Space Center, which "has the potential to save program costs." But for now, the Air Force is still planning to land the plane at Vandenberg, per usual.