space plane


The Space Plane Returns to Earth

, senior scientist

The third X-37B space plane flight is coming to an end this week, after a record 22 month long mission. We have written pretty extensively on the “space plane” here on ATN, and have a factsheet where we condensed that thinking. Read more >

Bookmark and Share

Claims about China’s Space Plane Unconvincing

, senior scientist

Following the two launches of the U.S. X-37B space plane, a number of news stories this fall (here and here) have speculated about how quickly China might catch up with the U.S. by developing its own “Shenlong” space plane. While Chinese interest in space planes is long-standing and well documented, the recent reports seem to derive their sense of timeliness and urgency from a May 2012 post by Andrew Erickson and Gabe Collins in their blog China Sign Post which claims the Shenlong had a test flight in January 2011.

But in fact the evidence that the Shenlong actually did have this test flight is quite shaky and should be examined much more closely before using it to conclude anything about the China’s progress.  Read more >

Bookmark and Share

X-37B Space Plane: Still in Search of a Mission

, senior scientist

On December 11, United Launch Alliance is scheduled to launch its X-37B prototype space plane for the Air Force from Cape Canaveral for the third time. Its mission, however, still remains a mystery. Read more >

Bookmark and Share

X-37B: How Much is Valet Parking Worth?

, co-director and senior scientist

The U.S. “space plane” is in the news again. This time, a poorly researched article in Spaceflight, the journal of the British Interplanetary Society, claimed that the X-37B was likely being used to spy on the Chinese Tiangong spacecraft from a nearly matching orbit.

The claim was based on an incomplete understanding of celestial mechanics and was thoroughly debunked—the spacecraft cross orbits only twice a day, and even then at very high speeds.

This claim is yet another effort to make sense of the X-37B. The Air Force is secretive about its purpose and budget, and observers have made vigorous efforts to come up with some mission that fits. The unique capability of the space plane—what makes it a “space plane” rather than a satellite or space capsule—is its ability to return to earth in a controlled manner and land on a runway.  

With the exception of the Space Shuttle (an obvious comparison, though many times bigger than the X-37B), spacecraft or equipment that needs to return to earth arrives by parachute. Even the successor to the Space Shuttle is being designed as a reusable capsule without wings, which can land on the ground or water using parachutes.

For getting things into space, mass is paramount. The equipment that permits the X-37B to land like an airplane (wings, heat shielding) is massive. This extra mass requires a larger launch vehicle and makes the launch much more expensive. The extra mass requires significantly more fuel to maneuver on orbit than the craft would without re-entry and landing equipment. Because of the need for a larger launcher, the X-37B is actually not as well suited to responsive space launch as other options.

Our bottom line is that the things a space plane can potentially do, including:

  • maneuvering on orbit to carry sensors; to visit satellites already on orbit to inspect, repair, or interfere with them; or to launch several small satellites into different orbits
  • providing a testbed for new technologies and materials, with a standard interface that payloads can be designed to fit
  • returning objects to earth from orbit

are all things that can be done more efficiently or more cheaply in other ways, with a maneuvering vehicle that that is much less massive. A less massive vehicle would have reduced launch costs or increased capacity to carry maneuvering fuel. In those cases in which something needs to be returned back to earth, or if the vehicle needs to be re-used, it can be returned by parachute rather than wings.

For a more detailed analysis see our earlier posts.

The only unique capability we can find for a space plane is to take something up to space and bring it back to land on a runway. That’s convenient, but how much are you willing to pay for valet parking?

Bookmark and Share

Gizmo-Intensive: The Real Purpose of the Space Plane?

, co-director and senior scientist

I’ve co-authored several posts in recent months analyzing the utility of the space plane—a small, un-piloted Space Shuttle. Those posts have made the point that we can’t find a mission for which the space plane seems well-suited compared to alternatives.

So, what’s going on? It’s occurred to me that maybe the system is more technology-driven than mission-driven.

And recently, as I was calculating launch costs and delta-V’s of the X-37B prototype space plane, I recalled an analysis I’d read of the Space Shuttle in 1995, which may shed light on the motivation behind the space plane as well.

This appears in the highly acclaimed analytic work Dave Barry’s Complete Guide to Guys (p. xiv):

Probably the ultimate example of the fundamental guy drive to have neat stuff is the Space Shuttle. Granted, the guys in charge of this program claim it has a Higher Scientific Purpose, namely to see how humans function in space. But of course we have known for years how humans function in space: They float around and say things like: “Looks real good, Houston!”

No, the real reason for the existence of the Space Shuttle is that it is one humongous and spectacularly gizmo-intensive item of hardware. Guys can tinker with it practically forever, and occasionally even get it to work, and use it to place other complex mechanical items into orbit, where they almost immediately break, which provides a great excuse to send the Space Shuttle up again. It’s Guy Heaven.

A similar explanation for the space plane makes as much sense as any other I’ve seen, especially since the Space Shuttle program is ending. It may even explain my own interest in the space plane.

Bookmark and Share