Astrium to develop re-ignitable engines for ESA

The two-year contract will see Astrium working on cryogenic engines (fuelled by liquid hydrogen and oxygen) for the upper stages of rocket launches.

The project, entitled Cryogenic Upper Stage Technologies (CUST), will focus on fuel management under zero gravity and the thermal insulation of the cryogenic fuel tanks.

‘It will be a huge challenge to develop the technologies needed to supply fuel to the engine after a period of weightlessness, but they are a vital necessity if we want to make more powerful and flexible launch vehicles,’ said Thomas Renk, head of the CUST project at Astrium.

One of the main challenges for Astrium is keeping the hydrogen and oxygen fuel in a liquid state while in zero gravity, which requires temperatures of -253ºC and -183ºC respectively.

Solar radiation causes space temperatures to fluctuate, so the company will need to develop insulation for the tanks and the rocket upper stages to prevent the fuel from evaporating.

Another challenge will be stopping the liquid fuel floating around the tank at zero gravity and ensuring it is immediately available at the feed line when the engine is re-ignited.

Re-ignitable engines are used for placing satellites into geostationary orbit, when rockets must coast at an intermediate height after the initial launch, before re-firing to reach the final orbit position.

‘Also, if you’re launching a probe to a comet, Mars or even the Moon, the fact that you can re-ignite allows you to do this more effectively,’ Silvio Sandrone, Astrium’s vice-president of launchers sales and business development, told The Engineer.

The ESA already has re-ignitable upper stages but they do not run on cryogenic fuel. ‘Cryogenic engines give a higher specific impulse so they are more efficient and the same amount of fuel can go further,’ said Sandrone. ‘But it is also a more delicate, sophisticated type of propulsion.

‘This technology is not necessarily just for [current ESA rocket launch system] Ariane 5 but looks much further away at future systems and can serve any type of re-ignitable stages.’

To support this work, two cryogenic fuel management experiments will be launched in 2011 on board the Texus sounding rocket, in co-operation with German Aerospace Centre (DLR).