GOCE: destined to reveal more about one of the Earth’s most intimate attributes – Gravity. – With Mark Drinkwater

Dr. Mark Drinkwater

GOCE Mission Scientist and Head of Mission Science Division,

ESA Earth Observation Programmes


The European Space Agency (ESA) is launching the Gravity field and steady-state Ocean Circulation Explorer (GOCE)

satellite to map our planet’s gravity field in unprecedented detail. As part of ESA’s Living Planet Programme, GOCE is the first of a series of Earth Explorer satellites in orbit, designed to provide information for understanding climate change as well as other critical Earth system variables.


The Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission is currently on schedule for lift off on a Rockot launch vehicle on Monday 16 March at 15:21hrs CET (14:21hrs GMT) from Plesetsk Cosmodrome in northern Russia.  GOCE, the European Space Agency’s first Earth Explorer mission, promises to match its good looks with high quality global gravity data acquired by a satellite and sensor package that embodies the latest technology (See GOCE mission site).



Once launched, GOCE will map minute variations in the pull of gravity exerted on the satellite and its six accelerometers as it orbits the Earth at an altitude of approximately 260 km. The low orbit requires the satellite to be sleek and aerodynamic in order to minimise the effects of drag exerted by the wisps of Earth’s atmosphere at this altitude. An revolutionary new ion propulsion system will be used to provide smooth thrust to counterbalance the effects of drag. This will provide the “quiet” free-fall environment required in which GOCE’s six ultra-sensitive accelerometers can make high fidelity measurements.


The Gradiometer employed by GOCE (comprising the six accelerometers) is an entirely new instrument concept which will enable gravity gradients to be measured in three-dimensions by differencing the accelerations measured by three pairs of accelerometers. Coupled with precise GPS measurements of the 3-d position of the satellite along its orbital trajectory, the data will

provide the Earth science community with exciting new data with which to improve our understanding of gravity. The mission duration is presently planned to be 24 months, though we hope to extend the mission as long as the reserve of vital propulsion fuel – Xenon – allows.


GOCE is a special satellite, and one which has been well worth waiting for. Gravity and its variation in space are fundamental to every dynamic process on Earth’s surface and in its interior. Improving our knowledge of how gravity affects the interaction between these processes has practical benefits in today’s changing world. An accurate gravity map – the geoid – is also crucial for geodesy applications and for defining a sea surface height reference model with which to accurately survey ocean circulation patterns and sea-level changes.


I would like to acknowledge at this point a lot of truly special people. My best wishes go out to the group of scientists who have helped, supported and elaborated the original idea, and the ESA Project team and engineers, and the Industrial consortium all of whom have shown great tenacity and endeavour in preparing this mission. Over the last 10 years, GOCE has been transformed from a dream, and an idea in the mind’s eye of the scientists, to something truly fantastic. It makes me proud that Europe is taking major steps forward in supporting such excellence in both engineering and science through the realisation of one of the most challenging space missions to date.


Please join us in watching the launch of GOCE. The launch will be transmitted at the ESA web site. 



EDITOR’S NOTE: Find yourself 5.55 minutes and learn more about the GOCE mission:



Images credits:

Launch Tower – ESA – S. Corvaja, 2009

Gradiometer instrument and GOCE spacecraft- ESA – AOES Medialab

    • Mark Drinkwater
    • March 17th, 2009

    I can happily report that the GOCE satellite was successfully launched from Plesetsk today and has been placed into the correct orbit by its Rockot launcher! At my time of writing, we have had contact with the satellite on two successive revolutions at the Kiruna and Svalbard ground stations, and now the launch teams take a well-deserved break. ESOC in Darmstadt is now controlling the satellite and will continue with the Early Operations Phase to establish the health of the satellite now we are safely “on orbit”.

    We are all elated that Europe has successfully opened a new Chapter in Earth Observation. The launch of GOCE is the first in a series of six Earth Explorer missions. Over the course of the next 9 months, we plan to launch the SMOS mission (in July), and then CryoSat-2 towards the end of the year. A busy year for ESA indeed, but a key marker for Europe in terms of consolidating its global position at the forefront of Earth Observation.

  1. March 16th, 2009
  2. March 17th, 2009

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