Zero-gravity fuel gauge set for tests on International Space Station

A new fuel system will “solve many of the longstanding problems of measuring propellant in space vessels in zero gravity”, its developers have claimed.

Unlike straightforward and reliable car fuel gauges, which rely on gravity, accurately measuring how full a tank is in space poses several challenges. Hampshire firm Atout Process aims to solve them with the Smart Tanks for Space (Smartts) system, which it will test onboard the International Space Station, funded by the European Space Agency (ESA).

Atout’s technology uses electrical capacitance tomography sensors to measure the mass of liquid in a tank, show where it is and how it is moving, and to calculate the resulting forces on the vehicle.

Smartts will be applicable to “any spacecraft using liquid or gaseous propellant, at any scale, providing accurate gauging in any gravity and any orientation”, the company’s website claims.

Accurate gauging could improve spacecraft efficiency, reduce the required propellant reserve, increase spacecraft lifetime, and prevent contribution to the space debris problem by allowing better end of life planning.

“We’re confident that Smartts can report, in real-time, accurate measurements of fuel, even in space,” said Andrew Hunt, chief executive at Atout. “Thanks to ESA, we’ll now get the chance to prove it in orbit through experiments on the International Space Station. It’s essential new technology for proposed new space industries, and will enable measurable in-orbit refuelling.”

Space engineers at Surrey Space Centre, part of the University of Surrey, will help build the prototype Smartts system. 

Centre director Professor Keith Ryden said: “Atout have a fantastic product and we’re helping them demonstrate its value. We have built many instruments to go to space, so we’re well placed to advise them and have the specialist equipment and facilities they’ll need, like clean rooms and machines to check Smartts can withstand the stresses of launch and the harsh conditions of space.

“Gauges like those used in cars don’t work in zero gravity, so alternative techniques are used in space which rely on estimates and calculations. However, errors can accumulate and there’s no real-time information, so mission designers have to factor in extra reserves of fuel, with significant associated costs.

“Smartts could be a real game-changer in the space sector, saving money and opening doors to new industries, and we’re keen to see how they operate in orbit.”

Atout will build the prototype Smartts system this year. ESA plans to launch it in 2025.