Feeds

Grav-mapping satellite fires ion engines

GOCE xenon-fed drives 'performing nominally' says ESA

Boost IT visibility and business value

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.

Gartner critical capabilities for enterprise endpoint backup

More from The Register

next story
LOHAN packs bags for SPACEPORT AMERICA!
Spanish launch goes titsup, we're off to the US of A
Gigantic toothless 'DRAGONS' dominated Earth's early skies
Gummy pterosaurs outlived toothy competitors
'Leccy racer whacks petrols in Oz race
ELMOFO rakes in two wins in sanctioned race
TRANSMUTATION claims US LENR company
Ten points of stuff out of a five pound bag
Boffins ID freakish spine-smothered prehistoric critter: The CLAW gave it away
Bizarre-looking creature actually related to velvet worms
CRR-CRRRK, beep, beep: Mars space truck backs out of slippery sand trap
Curiosity finds new drilling target after course correction
BAT-GOBBLING urban SPIDER QUEENS swell to ENORMOUS SIZE
But they'd lose a deathmatch against the coming Humvee-sized, armoured Arctic ones
Astronomers scramble for obs on new comet
Amateur gets fifth confirmed discovery
Boffins build CYBORG-MOTHRA but not for evil: For search & rescue
This tiny bio-bot will chew through your clothes then save your life
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
7 Elements of Radically Simple OS Migration
Avoid the typical headaches of OS migration during your next project by learning about 7 elements of radically simple OS migration.
BYOD's dark side: Data protection
An endpoint data protection solution that adds value to the user and the organization so it can protect itself from data loss as well as leverage corporate data.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?