Recent talk of slinging satellites into space has captured the imagination of the scientific press following the release of United States Air Force (USAF) research findings. New Scientist explained that the idea explored uses a hoop of superconducting magnets several kilometres wide, similar in appearance to a particle accelerator, to hurl satellites into space.

As far fetched as it may sound, the technology has its fans - but why? The answer: because once the initial capital has been invested, the launch of satellites into space could be significantly cheaper.

Accelerator concepts have been proposed several times before – but were previously regarded as non-viable because the payloads that could be launched would be too small to offer significant capability.

However, the success of missions such as SSTL's 6.5. kg SNAP-1 nanosatellite (pictured left), shows that useful missions can be performed using very small satellites.

Not resting on their laurels, SSTL is now developing PALMSAT with Surrey Space Centre (SSC) academics, which weighs just 1 kg, but incorporates all the capabilities of SNAP-1. As the name suggests, PALMSAT (bottom left) fits in the palm of your hand.

Clearly, providing they are adequately protected from damage, 1 kg satellites like PALMSAT could be launched into closely-spaced clusters, or more widely spaced constellations, by an accelerator of the sort that has been proposed by the USAF.



"This accelerator proposal is clearly interesting, and ties in well with SSTL's focus on reducing the costs of access to space. One of the challenges for our satellite engineers at SSTL would be to design an on-board propulsion system which would survive the enormous launch loads [g forces] from the accelerator and yet still be able to provide enough thrust to insert the satellites into orbit at the top of their initial launch trajectory. Without such a manoeuvre, the satellite payloads would simply re-enter the Earth's atmosphere." Commented Stuart Eves, SSTL.

Clusters and constellations offer particular advantages in terms of effective aperture and revisit times which are simply too expensive to achieve with large satellites.

The USAF interest in improved revisit times and rapid access to orbit stems from their "Responsive space" initiative, which reflects the fact that space is no longer just a strategic capability, but is increasingly being used to support military operations in theatre, where the response times clearly have to be much shorter.

Opinions in the blogosphere vary from Slashdot discussions about radial loading, meanwhile The Astronomy Blog have a great photo of the ring. Astronomy (blog)compares the new research to previous straight track proposals, while Redwolf are wondering what kind of satellites would be launched with the new launch technology.