Exploring the Physical World

Weizmann Institute Instrument Bound for Jupiter

• Science Tips • TAGS: Astrophysics, Space, Technology

Weizmann Institute scientists are planning an experiment for a mission to the giant planet


Credit: NASA/JPL/University of Arizona

Sometime in the year 2030, if all goes according to plan, some dozen groups around the world will begin receiving unique data streams sent from just above the planet Jupiter. Their instruments, which will include a device designed and constructed in Israel, will arrive there aboard the JUICE (JUpiter ICy satellite Explorer) spacecraft, a mission planned by the European Space Agency (ESA) to investigate the properties of our solar system’s largest planet and several of its moons. Among other things, the research groups participating in JUICE hope to discover whether the conditions for life exist anywhere in the vicinity of the planet, which is a “gas giant” complete with gaseous atmosphere.

“This is the first time that an Israeli-built device will be carried beyond the Earth’s orbit,” says Dr. Yohai Kaspi of the Weizmann Institute of Science’s Department of Earth and Planetary Sciences, who is the principal investigator on this effort. The project, conducted in collaboration with an Italian team from the University of Rome, is called 3GM (Gravity & Geophysics of Jupiter and Galilean Moons).

The Israeli contribution to the project is an atomic clock that will measure tiny vacillations in a radio beam provided by the Italian team. This clock must be so accurate it would lose less than a second in 100,000 years, so Dr. Kaspi has turned to the Israeli firm AccuBeat, which manufactures clocks that are used in high-tech aircraft, among other things. Its engineers, together with Dr. Kaspi and his team, including Drs. Eli Galanti and Marzia Parisi, have spent the last two years in research and development to design a device that should not only meet the strict demands of the experiment, but survive the eight-year trip and function in the conditions of space. Their design was recently approved for flight by the ESA. Israel’s Ministry of Science and Technology will fund the research, building, and assembly of the device.

For around two and a half years, as JUICE orbits Jupiter, the 3GM team will investigate the planet’s atmosphere by intercepting radio waves traveling through its gaseous atmosphere, timing them and measuring the angle at which the waves are deflected. This will enable them to decipher the atmosphere’s makeup.

During flybys of three of the planet’s moons – Europa, Ganymede, and Callisto – the 3GM instruments will help search for tides. Researchers observing the three have noted fluctuations in the moons’ gravity, which suggests that the large mass of Jupiter is creating tides in liquid oceans beneath the moons’ hard, icy exteriors. By measuring the variations in gravity, the researchers hope to learn how large these oceans are, what they are made of, and even whether their conditions might harbor life.

The JUICE teams are preparing for a launch in 2022. That gives them three years to get the various instruments ready and another three to assemble and test the craft. During the long wait – eight years – from launch to arrival, Dr. Kaspi intends to work on building theoretical models that can be tested against the data they will receive from their instruments.

Dr. Yohai Kaspi’s research is supported by the Helen Kimmel Center for Planetary Science.