While NASA has certainly had great success with its Juno spacecraft – even seeing the plucky probe propel itself into the record books as the most distant solar-powered spacecraft ever flown – the mission has not been without its issues. In mid-October of last year, two stubborn helium check valves prevented the probe from entering a closer orbit to the object of its attention – Jupiter. Then, later that month, the craft dipped in and out of safe mode. Because of these hiccups, NASA has just announced that it will be abandoning the maneuver to put the probe into a closer orbit, deeming it too risky.
That doesn't mean there isn't still value in the mission however. Since arriving at the gas giant in July 2016, Juno has already circled Jupiter through four 53-day orbits and returned impressive images and data back to Earth, including the fact that the gas giant has bigger and more powerful magnetic fields and aurora (which were also spotted by the Hubble space telescope).
While the plan was to fire its engines to bring it in for a closer 14-day orbit that would have allowed it to peer even deeper through the colorful cloud cover of the planet, it will now stay on its wider orbit where it will continue to carry out its observations.
"During a thorough review, we looked at multiple scenarios that would place Juno in a shorter-period orbit, but there was concern that another main engine burn could result in a less-than-desirable orbit," said Rick Nybakken, Juno project manager at NASA's Jet Propulsion Laboratory in California. "The bottom line is a burn represented a risk to completion of Juno's science objectives."
Putting a positive spin on the development, NASA said that it'll now benefit from "bonus science" in which Juno will observe how the outer edges of the Jovian magnetosphere interact with the solar wind, an objective that wasn't originally part of the mission. In addition, the space agency points out that now Juno won't have to spend as much time in Jupiter's fierce radiation belts, which could help extend its life.
"Juno is healthy, its science instruments are fully operational, and the data and images we've received are nothing short of amazing," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate in Washington. "The decision to forego the burn is the right thing to do – preserving a valuable asset so that Juno can continue its exciting journey of discovery."
Juno will now continue circling the planet on its 53-day orbit, getting as close as about 2,600 mi (4,100 km) to the tops of the Jovian clouds. It will continue this pattern until at least July 2018, which will see it complete 12 full orbits. The next time Juno's elliptical polar orbit will bring it in for another close flyby of Jupiter will be on March 27.