Feeds

Grav-mapping satellite fires ion engines

GOCE xenon-fed drives 'performing nominally' says ESA

Intelligent flash storage arrays

The European Space Agency (ESA) has confirmed that both the electric ion propulsion engines aboard its Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite are "performing nominally".

Artist's impression of GOCE orbiting over ice. Pic: ESAThe "cutting-edge" drives - built by Qinetiq - are designed to compensate for "the tiny amount of drag generated by the few wisps of atmosphere at GOCE's orbital height".

ESA explains: "This cutting-edge system does not burn fuel like a regular rocket motor. Instead, it is supplied with xenon from a 40-kg tank, which is converted to fast-moving ions - naked xenon atoms that have had some of their electrons stripped away by an electric discharge generated from solar energy. The ions are ejected toward the rear, giving a very gentle, steady and smooth thrust."

This thrust represents a "fantastically small force" of between 1 and 20 millinewtons (mN), but that's enough to maintain GOCE's "free-fall" orbit - currently decreasing at a rate of around 190 metres a day from an altitude of roughly 280 km.*

Spacecraft Operations Manager, Juan Piñeiro, said: "On Tuesday last week, we fired the B-unit of the electric ion propulsion, stepping it through 1, 3 and 8.3 mN of thrust. On Thursday, we fired the A-unit. Both are performing nominally."

All being well, the engines will - as part of the Drag-Free and Attitude Control Subsystem (DFACS) - automatically maintain GOCE's velocity and altitude while the scientists get down to the job in hand.

GOCE Mission Manager, Rune Floberghagen, explained: "Next comes the 'wake up' for the instruments, which puts us in the position to start operating the first-ever gradiometer to be flown in space. After confirming they work, we will be ready for intensive testing of the satellite and of the scientific data-processing system on the ground."

The gradiometer is designed to produce an accurate gravity map (geoid) of Earth. This will allow a better understanding of how our planet's gravity affects dynamic processes such as sea level trends, ocean circulation and tectonic movements. ®

Bootnote

*As we understand it, GOCE is currently in free-fall orbit descending to its final operating altitude of around 260 km, at which point the scientists will doubtless require it to stop free-falling into someone's back garden. We're happy to be corrected on this point if that's not the case.

Security for virtualized datacentres

More from The Register

next story
Boffins who stare at goats: I do believe they’re SHRINKING
Alpine chamois being squashed by global warming
Comet Siding Spring revealed as flying molehill
Hiding from this space pimple isn't going to do humanity's reputation any good
Experts brand LOHAN's squeaky-clean box
Phytosanitary treatment renders Vulture 2 crate fit for export
LONG ARM of the SAUR: Brachially gifted dino bone conundrum solved
Deinocheirus mirificus was a bit of a knuckle dragger
MARS NEEDS WOMEN, claims NASA pseudo 'naut: They eat less
'Some might find this idea offensive' boffin admits
No sail: NASA spikes Sunjammer
'Solar sail' demonstrator project binned
Carry On Cosmonaut: Willful Child is a poor taste Star Trek parody
Cringeworthy, crude and crass jokes abound in Steven Erikson’s sci-fi debut
prev story

Whitepapers

Choosing cloud Backup services
Demystify how you can address your data protection needs in your small- to medium-sized business and select the best online backup service to meet your needs.
Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.