Weizmann scientists shoot for the stars with unmanned Juno orbiter

Among the many questions Kaspi, Galanti and their colleagues would like to answer is this how deep are the weather patterns we observe on Jupiter’s surface.

By JUDY SIEGEL-ITZKOVICH
NASA releases beautiful time-lapse video of the Earth's horizon as seen from the International Space Station (photo credit: screenshot)
NASA releases beautiful time-lapse video of the Earth's horizon as seen from the International Space Station
(photo credit: screenshot)
When the Juno spacecraft of the US National Aeronautics and Space Administration enters orbit around Jupiter on Monday, the Weizmann Institute of Sciences’s Dr. Yohai Kaspi will be watching carefully. Part of the Juno science team, Kaspi is ready to help answer some of the burning questions about the planet in the solar system.
Juno has traveled more than two billion kilometers over nearly five years and, after some intricate maneuvers, the NASA spacecraft will go into a unique 14-day orbit that will allow it to get as close as 4,000 kilometers above the cloud tops of the giant planet – much closer than any mission ever before flown.
“For the first time,” Kaspi explained on Thursday, “we will have an opportunity to study the flows beneath the thick clouds we see covering Jupiter.” He and the Rehovot institute’s staff scientist Dr. Eli Galanti will be at the Jet Propulsion Laboratory in Pasadena, California, along with the other scientists and engineers on the Juno team, to witness the event.
With Juno already within the gravitational sphere of Jupiter, the team will be holding their breath as the speeding spacecraft aligns itself into a stable orbit and begins sending data. The research team has planned an eccentric circuit for the ship, so that it can swing in closely to observe and measure and then circle farther out to preserve its orbit.
Among the many questions Kaspi, Galanti and their colleagues would like to answer is this how deep are the weather patterns we observe on Jupiter’s surface.
These patterns are gas flows that appear as ordered stripes on the planet’s outer surface, and because there is no solid ground to disrupt them, they may extend deep into the interior.
Adding the third dimension to our understanding of these patterns could help to answer any number of other questions, including how do these patterns form, whether the outer layers rotate in sync with the inner ones, how thick is the famous Great Red Spot, and whether the planet has a solid inner core, which is key for understanding how planets form, said Kaspi.
Kaspi, who has been with the Juno project nearly a decade, has used that time to work out the tools for analyzing measurements that will be taken of the planet’s gravity. Since weather – the movement of mass around the planet – creates slight variations in the planet’s gravity at different points, Kaspi and colleagues will use the data from Juno’s measurements of the gravitational fields to “reverse calculate” the wind patterns that modified them.
In this way, he will help scientists “peer for the first time beneath the thick cloud layer” of Jupiter. Kaspi has already applied these tools to calculating the depth of weather patterns on Uranus and Neptune, showing that the high winds on those planets are confined to a relatively shallow upper layer, as well as to analyzing measurements of Jupiter and Saturn obtained from Earth-bound telescopes. But the Juno mission will provide the first opportunity to measure the differences in Jupiter’s gravitational fields precisely and accurately, and thus develop a clearer picture of the planet’s interior and atmospheric dynamics