Towards the end of 2012, a tiny satellite the shape of a cd rack will be blasted into space on top of a converted intercontinental ballistic missile, then be hurled into orbit by a spring-loaded pod. Although dwarfed by communications and military satellites, the launch of the UK Space Agency’s first nanosatellite will mark a milestone: kicking off a satellite industry for the rest of us.
By the time UKube-1 launches, it will have taken less than two years to move from concept to orbit – a dramatic reduction in time compared to most satellite launches – and will open space research to hundreds of organisations.
Clyde Space only got the go-ahead to proceed with its design from the newly formed UK Space Agency in November 2011. But speed is the essence of development in the burgeoning area of nanosatellites and calls for a different approach. The boxy shape of the UK‘s first official ‘cubesat’ is a testament to an approach that is all about using commercial off the shelf (COTS) parts and concepts to open space up to a wider variety of users.
Jamie Bowman, principal embedded systems engineer at UKube-1 participant Steepest Ascent, says: “The use of COTS means the barrier to entry for a small company is lower. Within the cubesat community, we are trying to commercialise the concept.”
Speaking at the 2011 Summer CubeSat Workshop earlier in the year, Clyde Space CEO Craig Clark said the rationale behind UKube-1 is to demonstrate the UK‘s space capability, as well as to encourage students at schools and universities to take part in experiments aboard the probe. The five payloads represent a mix of commercial and academic projects.
For example, alongside a payload that will allow avionics company Astrium to build more secure satellites by using cosmic radiation to generate true random numbers for use in encryption is myPocketQub, a host for experiments that will allow one user every day for a year to upload software and run it. “It’s an open source approach to doing space experimentation,” says Clark.
The payload experiments are coordinated through the Mission Interface Computer (MIC) developed by Steepest Ascent. “The MIC performs all the housekeeping tasks, such as gathering data, processing it and getting it back down to the ground,” says Bowman.
The original concept for the cubesat came from Stanford University professor Bob Twiggs, who worked with colleagues at his institution and Cal Poly to develop the hardware.
According to Cal Poly professor Jordi Puig-Suari, the overall design of the cubesat came down to the availability of components at the end of the 1990s. They settled on a 10cm cube as this could comfortably hold a small stack of PC/104 embedded computer and peripheral boards.
The basic cube, however, proved too restrictive and even the first launch violated the original standard. One of the satellites was a double height or 2U model; the other, an even taller 3U design. But, by adopting the same 10 x 10cm footprint, a 1U, 2U or 3U probes can be loaded into a spring loaded Poly-PicoSatellite Orbital Deployer (P-POD), which can accommodate up to three cubesats. Standardisation on footprint makes booking a launch far less of an issue: it’s still possible to mix and match cubesat sizes within a single P-POD.
By 2010, more than 30 cubesats had made it into orbit. The form factor is now common enough for launch companies to put P-PODs into their rockets without knowing who will rent that space beforehand. Cubesat developers do not have to aim for a specific launch slot; they can develop their system in the knowledge that someone, somewhere will be willing to send it into space. The ready availability of launchers makes it easier for companies to get involved in space projects: one of the reasons why UKube-1 is seen as a useful first step in building the UK‘s expertise in satellite technology.