Juno: NASA’s Jupiter orbiter has an engine issue

The Juno space probe arrived at Jupiter to much fanfare in July, having travelled almost three billion kilometres to reach the gas giant.

Now, it appears that the orbiter is suffering from an engine-related problem, NASA confirmed in a statement.

The issue was discovered after engineers decided to test systems ahead of a 19 October “period reduction manoeuvre” or PRM. This type of burn is meant to reduce the probe’s orbital period around Jupiter from 53.4 days to just 14 days. Unfortunately, the issue means that the scheduled burn has been postponed for now.

Juno has suffered an engine-related issue, but it’s still gathering a ton of valuable data

“Telemetry indicates that two helium check valves that play an important role in the firing of the spacecraft’s main engine did not operate as expected during a command sequence that was initiated yesterday,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory, in the statement.

“The valves should have opened in a few seconds, but it took several minutes. We need to better understand this issue before moving forward with a burn of the main engine.”

If the problem is resolved, the next opportunity for the burn would come on 11 December. Nevertheless, scientists are still very happy with the data Juno has been and will continue to gather.

“It is important to note that the orbital period does not affect the quality of the science that takes place during one of Juno’s close flybys of Jupiter,” said Scott Bolton, principal investigator of Juno.