America seeks faster ways to launch military satellites

BY SHOOTING A missile into one of its own satellites in March, India upped the ante. The immediate intention, suggests Jeffrey Caton, a retired American air-force colonel who teaches at the Army War College, was to fire “a shot across the bow” of India’s rival China. The Chinese had, after all, blown up one of their own satellites in 2007, in a similar demonstration of their ability to do such things. India’s test, along with the wider profusion of anti-satellite weapons, has lent credence to the worries of defence chiefs around the world who believe that future conflicts between great powers will stretch into space.

Satellites are too militarily useful to pretend that adversaries will consider them off-limits, says William Roper, the air force’s assistant secretary for technology and acquisitions. America must therefore ready itself for warfare in space. America is, indeed, especially vulnerable. It has more space assets than any other country and relies on them more for its war-fighting capability. Moreover, as John Hyten, the vice-chairman of America’s Joint Chiefs of Staff, eloquently puts it, America’s kit in space consists mainly of large, “exquisite” satellites that make for “big, fat, juicy targets”.

First responders

One approach to reducing the risk this poses is to make those targets less fat and juicy. That is happening, as both civil and military satellite users shrink their hardware and scatter its functions over multiple pieces of equipment. In particular, people are deploying more of the modular designs known as cubesats. Among other things, that means individual satellites are smaller and cheaper, and therefore easier to stockpile in advance. But for this approach to be really useful, it must also be possible to launch them quickly if, for whatever reason (whether enemy action or otherwise), an orbiting asset stops working and needs replacing.

That concept is known as “responsive space”, and, in today’s outsourced world, it often means calling on the private sector to do the actual launching. American officials are therefore pleased that a firm called Rocket Lab, whose services they often rely on for lifting payloads of up to 150kg, has quickened the tempo of cubesat launches from its pad in New Zealand to once a month. Rocket Lab hopes that, by early next year, it will have improved this rate to once a fortnight—an objective which will be assisted by its construction of a second launch pad in Virginia.

Rocket Lab is also a pioneer of the 3D printing of rocket parts, such as the nozzles, valves, pumps and main combustion chamber of the motor. That reduces the number of components involved, and greatly speeds up manufacture and assembly. Rockets being expensive, no one wants to carry a large inventory of them. Having a “just in time” approach to launcher availability is therefore desirable.

Relativity Space, another American firm, also plans to print its rocket, the Terran 1. This will carry a payload of 900kg. Its first orbital launch is scheduled for next year. Relativity Space’s biggest printers produce five-metre sections of propellant tank. Its most precise ones create engine parts with an accuracy of 40 millionths of a metre. A conventionally manufactured rocket of similar size would contain, the firm says, nearly 100,000 parts. Terran 1 has less than 1,000. That simplifies the supply chain and accelerates the testing of parts.

Bright ideas

Speeding up launcher production in this way helps. But it will not be enough if America is to fulfil its goal of launching replacement satellites with a day’s notice. That is one reason, says Mr Roper, why the air force is now buying, at a series of pitching events that started in March, ideas for ways of prevailing in “high end” orbital combat. Encouragingly for proposers of such ideas, little bureaucracy is involved. Settlement for those accepted is immediate—the air force sidesteps its lumbering payments system by using official credit cards to transfer money instantly to people’s PayPal accounts. Those who present clever proposals can thus pocket awards exceeding $100,000 within minutes. The latest of these pitching meetings, on November 5th and 6th, resulted in on-the-spot contracts worth $22.5m.

Meanwhile DARPA, America’s main military-research organisation, is trying to organise a responsive-space competition of its own. Next year it hopes to hold a challenge in which teams will attempt launches twice in a matter of days or weeks, each time learning only shortly beforehand of the mission’s location, destination orbit and payload characteristics. This has never been done before. Programming the computers takes time, and the rocket must be trimmed in advance for the particular trajectory, taking into account such factors as the weather. Prizes of up to $10m will be awarded.

It is a measure of the task’s difficulty that, of the 55 teams which signed up initially, only three qualified, and two have subsequently dropped out. The name of the remaining competitor is secret.

At least one of the dropouts has not given up completely, though. That firm, Virgin Orbit, has turned a Boeing 747-400 into a flying launch pad. At an altitude of about 10.7km, the aircraft releases a rocket called LauncherOne. This rocket’s engine ignites after 4.8 seconds of freefall.

Such launches, Virgin Orbit says, can take place above nasty weather. They also make it easier to reach east-to-west “retrograde” orbits, because the launching plane can fly in the opposite direction to Earth’s spin, reducing the launch velocity required for such an orbit. Though Virgin Orbit’s system has yet to put a satellite into orbit, Britain’s Royal Air Force seems interested. In July it announced a deal to launch small satellites on notices possibly as short as a week. By today’s standards, that is, indeed, pretty responsive.■