780 days in orbit on its fifth and longest mission.

But while the orbiter’s existence and the durations of its missions are known, there’s

not a lot of information available to the public about what exactly it’s doing while

it’s up there.

So based on what we do know, what else can we figure out?

If you haven’t heard of the X-37B, I’ll get you up to speed.

The craft is an uncrewed robotic orbiter that sort of looks like a miniaturized space shuttle.

It’s just under nine meters long and nearly three meters tall, with a wingspan of 4.6 meters,

so it’s roughly the size of a school bus, with a cargo bay about the size of a pickup truck’s.

The project originally started in 1999 under the purview of NASA, but in 2004 it was taken

over by the Defense Advanced Research Projects Agency, better known as DARPA.

From then on, the X-37 was classified, though we do know that the project is run by the Air Force’s

Rapid Capabilities Office.

It launches out of Cape Canaveral in Florida, with the latest mission riding SpaceX’s

Falcon 9 into orbit for the first time, and the last two missions landed right next door

to where they launched.

It’s believed there are two X-37Bs, and they were built by Boeing’s Phantom Works

Division.

Spooky.

The Air Force’s official fact sheet on the X-37B’s purpose doesn’t clear much up.

It reads, and I quote, “The primary objectives of the X-37B are twofold: reusable spacecraft

technologies for America's future in space and operating experiments which can be returned

to, and examined, on Earth."

Basically, it just says it’s a reusable craft that carries things into space and brings

them back.

And that’s where the facts start to dry up and speculation fills in the gaps.

One theory imagines that since it has the ability to change its orbit, the X-37B might

be used to actually sneak up on and grab other nation’s satellites.

But while altering its orbit does make it more difficult to track, even dedicated amateur

astronomers can still keep tabs on it, and experts think the craft is too small and not

maneuverable enough to snatch satellites out of orbit.

Experts think it’s more likely a testbed for technologies that will be a part of top-secret

missions of the future, things like spy satellites.

Though it can orbit at altitudes as high as 805 km, it’s been going around the earth

at a distance around just 320 km, lower than the ISS.

That close orbit would enable a spy satellite to take higher resolution pictures, but would

also require more fuel to keep aloft and add to the craft’s weight.

To make lighter and cheaper reconnaissance satellites cruise at that altitude, they would

need a new type of propulsion system.

As it happens, one of the few unclassified payloads we know the X-37B has brought into

orbit was an experimental Hall effect thruster.

The only other payloads we know about was a NASA materials science experiment that accompanied

the Hall thruster on the X-37B’s 4th mission, and a highly efficient heat pipe that went

up on this latest flight.

You know, things that are very… uninteresting.

While it’s tempting to let our imaginations run rampant, it seems likely that the X-37B

itself isn’t a space weapon or a reconnaissance platform or some other cloak-and-dagger craft.

It's probably what the Air Force says it is, a cheap reusable testbed that allows for quick

turnaround times for experiments that can only be conducted in space.

Now, what those experiments are and how they’ll be used, that’s the real question, and unfortunately,

I don’t have the security clearance to give you an answer.

So you’ll probably never hitch a ride on the X-37B, but for a cool 250 thousand dollars

you may be able to buy a ticket on Virgin Galactic.

To learn more check out this video here.

How do you think those experiments will be used?

Let us know in the comments below if you liked this episode.

Make sure to subscribe to Seeker and thanks for watching.