TOP-SECRET SPACE SHUTTLE
An X-37B has been sent into orbit for its sixth mystery mission. All About Space uncovers what the ex-NASA spacecraft has really been up to
There are many mysteries surrounding the nature of the universe. Why do pulsars pulse? What is dark matter? Is there life on Mars? But there are also some mind-bending teasers that have been created by humans which perplex even the greatest of minds. What, for instance, has the US military’s unmanned X-37B space plane been up to during its numerous orbits of Earth? And why have the missions – including the most recent one launched in May this year – been shrouded in secrecy?
Few people outside the project know, and even fewer will give you the full lowdown on the true purpose of X-37B. This is a military mission, and most of the information about it is firmly classified. As such it has sent conspiracy theories into complete overdrive, especially since it is flying far in excess of the 270 days it was originally built for. Some say the craft is spying on other nations; others believe it could be a space bomber. The truth may well be much more mundane than that, but it is hugely fascinating nonetheless.
What we do know is that X-37B exists, and that aircraft and rockets with the ‘X’ designation have long been known to be experimental, high-speed vehicles. We also know what it looks like, what it contains and how it is powered. These are titbits of information which the military appears quite happy to discuss, but then that level of detail was already out there before the US Department of Defense took control of the project.
In 1999 NASA, Boeing and the US Air Force embarked on a $173 million (£135 million) venture to create a vehicle that could achieve orbit in outer space, collect test data in the Mach 25 re-entry region of flight and make autonomous landings. “We’re going to do some missions in orbit, like rendezvous and station keeping,” Boeing program manager David Manley told CNN in 1999. “On the second flight we plan to stay up there for almost three weeks and test some of our systems.”
At that stage X-37 was to be a test bed for technologies such as thermal protection systems, storage and aerodynamic features for reusable space vehicles. NASA released an artist’s impression of the space plane, shown to be far smaller than the Space Shuttle, with a payload bay that could be used for experiments. The space agency and its partners said they wanted the plane – dubbed the Orbital Test Vehicle (OTV) – to reduce launch costs by 90 per cent, making space transportation and operations much more affordable.
As well as experimenting with non-toxic liquid propellants, they also hoped that tests would result in safer and more reliable flights. However, in 2001 the project hit the rocks when the Air Force pulled its funding. Although the project went ahead anyway, with Boeing awarded a new $301 million (£236 million) contract and asked to build two X-37 vehicles, one of which would be used in drop tests within the atmosphere, development ended up being pulled back two years later. NASA concluded that it wasn’t sitting well with its agenda of space exploration, and so in 2004 it handed the project to the Defense Advanced Research Projects Agency (DARPA). It was then that the project became classified, so much so that NASA said it couldn’t even name DARPA to the public. It only did so when it was given permission a couple of days later.
But why did the department take over? “During the years when Donald Rumsfeld was secretary of defense, the Pentagon was pushed to move from thinking in terms of platforms such as ships, planes and tanks to capabilities,” reckons Joan Johnson Freese, a professor at the US Naval War College in Newport, Rhode Island, indicating that the military saw the potential possibilities on offer. “The more capabilities a technology or piece of equipment could deliver, the higher its overall value.”
With the days of full openness about the project coming to an end, speculation began to mount. But it wasn’t surprising. “I think the secrecy is routine,” says physicist Mark Gubrud of the peace, war and defense curriculum at the University of North Carolina. “Once it’s been decided that something is classified, they carry out that policy.” And yet interestingly, they didn’t go down the path of a blanket ban on all information.
“They do announce the launches, which are observed from the ground and tracked by amateurs,” says Gubrud. DARPA, together with the Space and Intelligence division of Boeing and NASA, has issued photos of X-37B, and in the early days it detailed drop tests – the act of raising the spacecraft to a certain altitude and then releasing it. They spoke of difficulties encountered during testing of the in-flight characteristics, and they didn’t hide its components, nor that it is powered by a single Aerojet engine with storable propellants. “But they’ve decided to keep the payloads secret,” Gubrud adds. “That definitely indicates that the payloads have a national security purpose.”
The first X-37B – OTV-1 – was launched atop an Atlas V on 22 April 2010. As expected, no details were forthcoming about its orbit or the experiments that had been packed into the payload bay. It led to speculation that it was perhaps being used as a spy satellite. Indeed, there is a wide agreement among experts that it is perhaps being used for some sort of secret reconnaissance. But the Pentagon has strongly denied suggestions that OTV-1 was being
tested as a weapon, categorically stating that it was not supporting the development of space-based weapons. So what does the Pentagon say? Only that X-37B would demonstrate experiments and allow satellite sensors, subsystems, components and ‘associated technologies’ to fly to space and back.
“A lot of those technologies are probably dual-use in the sense that they have both military and nonmilitary applications, but that’s almost always the case for space technologies,” says Brian Weeden, director of program planning for the non-profit Secure World Foundation. One thing’s for sure: one mission has not been enough. A second X-37B took off from an Atlas V on 5 March 2011. While the first had spent 224 days, 9 hours and 24 minutes in space, this one spent 468 days, 14 hours and 2 minutes in low-Earth orbit – surprising given that it was only built for 270 days travel. Again the payload was not revealed, although as with the first craft there was a folded solar panel in the payload bay that could be opened to power the space plane on its mission. On 11 December 2012 the first X-37B embarked on its second mission – the third mission in total. This time the US Air Force said it was being used as part of a learning process, building on the results of the first flight. This time it didn’t make frequent orbital manoeuvres, so there was some sort of learning process going on. But to what aim?
“The X-37B is a technology test bed,” says Johnson-Freese. “It likely wasn’t designed with a
particular purpose in mind, but rather to test its feasible capabilities across a wide range of options. Clearly from the number of missions flown, the duration of the missions flown and the variety of speculated tasks it has carried out – including orbit changes and experiments carried on board that we know about – the Air Force is pushing the envelope to determine what the vehicle can do.”
Then to the fourth mission, which launched on 20 May 2015 using the second X-37B vehicle. This time there seemed to be more information, although the Air Force, which ran the program via its Rapid Capabilities Office, wouldn’t confirm if the objects on board were the same as the previous missions. Conspiracy theories cropped up: did it take out satellites – we’d probably have found out soon enough if it did – or was it on surveillance?
What we know for certain is that it was being used to test the onboard 4.5-kilowatt Hall thrusters, which could allow for even longer flights. “This is a type of ion engine,” explains Weeden, “and it is different from the typical rocket engines that use chemical propulsion.” Why is this important though? “Chemical rocket engines typically need to carry significant amounts of one or two different fuels, which gives them significant thrust, but only
for relatively short periods of time. Ion engines use a very small amount of a noble gas, such as xenon, and electricity to accelerate that gas to very high speeds,” Weeden adds. “The result is a lot less ‘oomph’, but much more efficient thrust that can last for a much longer period of time. It’s similar to comparing a race car that can go really fast for a few laps to a solar-powered electric car that takes a long time to get up to speed but can keep going for a long, long time.”
With a fifth flight launched by a SpaceX Falcon 9 on 7 September 2017 and the latest on 17 May this year – reverting back to an Atlas V – these missions are likely to continue testing advanced guidance, navigation and control; avionics; high-temperature structures and seals; lightweight electromechanical flight systems; advanced propulsion systems; thermal protection systems and the autonomous methods of orbital flight, re-entry and landing – all things that the project managers have stated it is doing without delving into very much detail.
Does that completely rule out that it could be a space bomber, though? “I do not believe that X-37B is well adapted for any role as a space weapon,” says Gubrud. “Its re-entry tiles, wings and landing gear are just dead weight if you are using it to manoeuvre and attack in space or even just inspect foreign satellites. Nor is it likely to be feasible to grab adversary satellites and bring them down using the X-37B. It is too small and not equipped with robotic tools that would be needed to grab and secure a satellite and trim off its antennae, solar panels and so on to fit it and secure it in the small cargo bay.”
So no part could be for military use? “Since the overwhelming amount of space technology is dualuse, certainly some of those capabilities could be considered weapons-related, if only peripherally,” says Johnson-Freese. Mystery once more, but ion engines certainly aren’t unique to the military – many satellites use them today. However, as Weeden says, there is a high feasibility that the X-37B contains intelligence-gathering sensors such as radar, optical and infrared, and that the thrusters will allow for the development of lighter low-orbit satellites that could take better ground images. “My guess is that they include some classified sensor technologies for remote sensing,” he explains. “That could include optical imaging sensors, although given the orbit of the X-37B, it’s more likely to be radar imagers or signals intelligence sensors.”
We can’t say whether or not we will ever truly discover all that is on board X-37B. Neither do we know everything it has been doing in the time that it has been in orbit across six flights. One thing’s for sure though: those out of the loop will be keeping a close eye on it for the foreseeable future.