Scientists at the University of Surrey are developing a new way to power low-orbit spacecraft using – literally – thin air.

Surrey Space Centre aims to enable extremely low-altitude spacecraft orbits in the upper atmosphere, thanks to funding from the UK Space Agency.

This new spacecraft concept could offer new capabilities in Earth observation, climate monitoring and satellite communications.

Dr Andrea Lucca Fabris, principal investigator from Surrey Space Centre and an electric propulsion specialist, said:

“There are benefits to flying in very low altitude orbits, like being able to operate Earth observation at much higher resolutions than offered at present.

“It could also mean faster telecommunications, and it opens the door to new scientific discoveries about conditions in the ionosphere, which could help develop more accurate atmospheric models.”

The thin air at extremely low altitude orbits means a different type of spacecraft design and propulsion is needed compared with those used by conventional spacecraft operating in the vacuum of traditional low Earth orbits.

Air-breathing electric propulsion harnesses upper atmospheric air as propellant for an electric thruster.

This allows spacecraft to maintain their orbital altitude via drag-compensation, removing the need to store propellant on board. It means mission lifetimes do not have to be limited by propellant capacity.

Dr Mansur Tisaev, who recently completed his PhD at Surrey Space Centre said:

“We’ve been developing a cathode, or neutraliser, to work in electrostatic thrusters operating in the thin air found in ultra-low Earth orbit. By collecting and compressing the gases at that altitude, we can create a propellant flow that is ionised (i.e., transformed into a mix of charged particles) and accelerated using combinations of electric and magnetic fields, harnessing electrical power from solar panels.”

The UK Space Agency have awarded the team £250k for a one year project to develop their concept. This will fund conceptual design, propulsion testing, orbital mechanics analyses and aerodynamic simulations.

The activities will be a joint effort between the propulsion (Dr Andrea Lucca Fabris), astrodynamics (Dr Nicola Baresi), spacecraft engineering (Prof Craig Underwood) groups of the Surrey Space Centre and the Surrey’s Centre for Aerodynamics and Environmental Flow (Dr Olaf Marxen).

ENDS