Tscientists don’t look at a globe. They turn to a map called the geoid, which shows a hypothetical global ocean without tides and currents, shaped only by gravity. Scientists use the geoid to determine how oceans circulate, how sea levels rise and fall, how ice caps recede—and how climate change affects them all. To map the geoid with unparalleled precision, the European Space Agency
(ESA) launched a multiyear project to build and launch a gravity-measuring satellite—the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE).
The planning and development alone would take more than a decade.
After an initial phase of feasibility testing and preliminary definition, which
ran from July 1998 to July 1999, project sponsor ESA selected GOCE as the
inaugural mission of its Earth Explorers program, a series of expeditions to
better understand Earth’s systems and how human activity affects them. In
September 2000, ESA appointed GOCE’s project manager: Danilo Muzi, an
From the start, the project’s first-of-its-kind technology presented daunting
“GOCE was not a remake or, aside from a few minor exceptions, even a par-
tial reuse of existing designs and equipment,” says Mr. Muzi, Earth Explorers
program manager, ESA, Noordwijk, the Netherlands.
“It was all brand-new and state-of-the-art. Scientists
had been waiting for this for 15 or 20 years. So when
the mission was selected, we had strong interest and
expectations from a community of scientists.”
Those stakeholders would prove invaluable to the
A UNION IN EUROPE
As part of the ESA’s “fair return” principle, member
states across the European Union get back from the
ESA the equivalent worth of what they invest in its
programs. To achieve this, the ESA funnels jobs and
contracts to those countries. As a result, ESA’s proj-
ects become transnational collaborations—which
adds cultural hurdles to the technological and logistical ones. “GOCE really
was a European endeavor,” Mr. Muzi says.
“In some cases, you’re giving jobs to industries in new member states that
do not have a very long history of development of space hardware or other
TO FIGURE OUT HOW
A precise map of the geoid will help scientists
study climate change and how oceans
THE EARTH REALLY WORKS,