"The orbital period does not affect the quality of the science collected by Juno on each flyby, since the altitude over Jupiter will be the same at the time of closest approach. In fact, the longer orbit provides new opportunities that allow further exploration of the far reaches of space dominated by Jupiter's magnetic field, increasing the value of Juno's research. ... The original Juno flight plan envisioned the spacecraft looping around Jupiter twice in 53-day orbits, then reducing its orbital period to 14 days for the remainder of the mission. However, two helium check valves that are part of the plumbing for the spacecraft's main engine did not operate as expected when the propulsion system was pressurized in October. Telemetry from the spacecraft indicated that it took several minutes for the valves to open, while it took only a few seconds during past main engine firings. ... Juno's larger 53-day orbit allows for "bonus science" that wasn't part of the original mission design."
Keith's note: So NASA's Juno spacecraft has engine problems that prevent it from accomplishing its planned i.e. optimal science mission. But that's OK since NASA says that none of the science is affected by the engine problems. Indeed, they say that the science is better - and they get "Bonus science" too! Bonus science is good, yes? But wait: if Juno's science is not affected by engine failures - indeed its now better without the engine firings - then why did they plan the engine firings and orbit changes in the first place?
And all of these extra longer orbits will require 3-4 years to complete to get all that bonus science goodness. Oh yes: the spacecraft was not designed to operate that long - and it is going to cost another $100 million or so to operate the spacecraft during this time - not something NASA has in its budget. When you read these feel good releases that try and make technical failures look like good news just remember that NASA = Never A Straight Answer