NASA’s Juno probe has been orbiting Jupiter since July 4, 2016, and currently completes one orbit every 53 days. The Juno team has scrubbed plans to change the orbit to one that circles Jupiter every 14 days after telemetry from two valves in the main engine indicated that they may not be functioning properly. In a statement released by NASA, officials said that the scientific instruments are still functioning properly and the probe will be capable of executing its primary science objectives from its current orbit.
Juno completed its fourth orbit around Jupiter on February 2nd. On March 27, the probe is expected to make the closest approach to Jupiter in its orbit, known as a perijove. The perijove brings Juno within 4,100 kilometers (2,600 miles) of Jupiter’s cloud cover, during which it can peer beneath the clouds and make observations of Jupiter’s auroras. The data that Juno gathers during this period will provide better information about Jupiter’s origin, structure, atmosphere, and magnetosphere. The 53-day orbital period also provides better opportunities to observe the far reaches of space dominated by Jupiter’s magnetic field. During its previous orbits, Juno has returned data that led to the discovery that Jupiter’s magnetic field and auroras are more powerful than scientists previously believed and the belts and zones that have the greatest influence on the cloud belts extend deep into the planet’s interior. Papers based on these discoveries are expected to be published upon peer review.
The longer orbital period also exposes Juno to less radiation by giving it a break from the intense radiation belts around Jupiter, which can affect its electronics’ lifespan. Because Juno won’t change its orbit to one with a 14-day orbital period, scientists hope that Juno will have a longer lifespan and be able to produce what NASA calls “bonus science” through possible extensions of its mission. Any extension will, of course, have to be approved by NASA’s administration.
Juno’s primary mission will continue until July 2018 and the spacecraft is expected to make 12 orbits under the revised flight plan. “The science will be just as spectacular as with our original plan,” Scott Bolton, Juno principal investigator from Southwest Research Institute in San Antonio, said of the change to Juno’s mission plan.