GOCE's 'heart' starts beating

Apr 08, 2009
The sleek aerodynamic design of GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) immediately sets it apart from most other satellites. This unique five-metre long spacecraft has none of the usual moving parts. The satellite together with its sensor, system of supporting instrumentation and control elements actually form a single composite gravity-measuring device. Credits: ESA - AOES Medialab

GOCE's highly sensitive gradiometer instrument has been switched on and is producing data. Forming the heart of GOCE, the gradiometer is specifically designed to measure Earth's gravity field with unprecedented accuracy.

"We are very pleased with what we have seen from the gradiometer from the moment it was switched on. All accelerometer sensor heads are working in very good health and provide meaningful data," Project Manager Danilo Muzi said.

The gradiometer consists of three pairs of identical ultra-sensitive accelerometers, each mounted to point in orthogonal directions to allow the simultaneous measurement of the spatial variations of the .

With the switching on of the gradiometer, all systems on the have now been activated. The satellite's sophisticated electric ion propulsion system was switched on last week and continues to operate normally.

In order to get the maximum performance from the gradiometer, GOCE was designed to provide a highly stable and undisturbed environment. However, GOCE has to orbit Earth close enough to measure the tiny differences in gravity, which forces it to endure significant drag from the uppermost layers of the atmosphere.

The atmospheric drag is compensated for by the ion engine, which is able to deliver between 1 and 20 milliNewtons of thrust (the force equivalent to our exhaling).

GOCE was injected into orbit at an altitude of 283 km on 17 March. Since then, it has been freefalling at a rate of 150 to 200 m a day and will continue to do so until it enters 'drag-free mode' at an altitude of 273 km.

At this altitude, the satellite will actively compensate for the effect of air drag and its payload will undergo a further six weeks of commissioning and calibration. Mission operations are scheduled to start in summer 2009.

"With the ion engine and the gradiometer working, we have started to tune the satellite and its instruments," GOCE System Manager Michael Fehringer said.

"We have a lot of work ahead of us, but it is a highly exciting time for everyone involved in the mission," GOCE Mission Manager Rune Floberghagen added.

Data from GOCE will be used to create an extremely accurate map of Earth's gravity field. Together with altimetry data from missions, such as ESA's Envisat, the GOCE gravity map will allow scientists to measure sea-surface height more accurately and understand sea-level change and ocean circulation better.

Source: European Space Agency (news : web)

Explore further: Astronauts to reveal sobering data on asteroid impacts

add to favorites email to friend print save as pdf

Related Stories

GOCE's electric ion propulsion engine switched on

Apr 06, 2009

(PhysOrg.com) -- GOCE's sophisticated electric ion propulsion system has been switched on and confirmed to be operating normally, marking another crucial milestone in the satellite's post-launch commissioning ...

GOCE successfully completes early orbit phase

Mar 20, 2009

ESA's GOCE satellite was formally declared ready for work at 01:00 CET on 20 March. During the critical Launch and Early Orbit Phase beginning with separation from its booster on 17 March, GOCE was checked ...

ESA's Earth Explorer gravity satellite on show

Jul 19, 2007

GOCE, ESA’s first satellite dedicated to measuring the Earth’s gravity field, has been presented to the press today in Turin, Italy, before being shipped to ESTEC – the space agency’s research and ...

March launch planned for GOCE gravity mission (Video)

Feb 04, 2009

(PhysOrg.com) -- ESA is now gearing up to return to Russia to oversee preparations for the launch of its GOCE satellite - now envisaged for launch on 16 March 2009. This follows implementation of the corrective ...

Earth Explorer mission GOCE launches

Mar 17, 2009

This afternoon, the Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite developed by the European Space Agency (ESA) was lofted into a near-Sun-synchronous, low Earth orbit by a Rockot ...

Recommended for you

Astronauts to reveal sobering data on asteroid impacts

1 hour ago

This Earth Day, Tuesday, April 22, three former NASA astronauts will present new evidence that our planet has experienced many more large-scale asteroid impacts over the past decade than previously thought… ...

Rosetta instrument commissioning continues

1 hour ago

We're now in week four of six dedicated to commissioning Rosetta's science instruments after the long hibernation period, with the majority now having completed at least a first initial switch on.

Astronaut salary

2 hours ago

Talk about a high-flying career! Being a government astronaut means you have the chance to go into space and take part in some neat projects—such as going on spacewalks, moving robotic arms and doing science ...

Red moon at night; stargazer's delight

21 hours ago

Monday night's lunar eclipse proved just as delightful as expected to those able to view it. On the East Coast, cloudy skies may have gotten in the way, but at the National Science Foundation's National Optical ...

Meteorites yield clues to Martian early atmosphere

23 hours ago

(Phys.org) —Geologists who analyzed 40 meteorites that fell to Earth from Mars unlocked secrets of the Martian atmosphere hidden in the chemical signatures of these ancient rocks. Their study, published ...

User comments : 0

More news stories

A sharp eye on Southern binary stars

Unlike our sun, with its retinue of orbiting planets, many stars in the sky orbit around a second star. These binary stars, with orbital periods ranging from days to centuries, have long been the primary ...

Hubble image: A cross-section of the universe

An image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history. They range ...

Astronaut salary

Talk about a high-flying career! Being a government astronaut means you have the chance to go into space and take part in some neat projects—such as going on spacewalks, moving robotic arms and doing science ...

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Tiny power plants hold promise for nuclear energy

Small underground nuclear power plants that could be cheaper to build than their behemoth counterparts may herald the future for an energy industry under intense scrutiny since the Fukushima disaster, the ...

Hand out money with my mobile? I think I'm ready

A service is soon to launch in the UK that will enable us to transfer money to other people using just their name and mobile number. Paym is being hailed as a revolution in banking because you can pay peopl ...