Cav's Place

Yesterday, at 16:25 GMT, Juno was successfully launched on its five-year journey to Jupiter. The launch, originally scheduled for 15:34 GMT, was delayed by an anomaly noticed during the final programmed launch timer hold. After several extensions of the hold, what was originally feared to be a helium leak in the rocket’s Centaur upper stage was proven to be a small problem on the “ground side”, which could be quickly mitigated inside the launch window, which ended at 16:43 GMT.
Now, after receiving confirmation, some two hours after launch, of the successful deployment of all three solar arrays, we pretty much sit and wait. The flight plan reveals that the spacecraft will cruise for a little over one year, reaching a point past the orbit of Mars, then make some maneuvers designed to put it on course for an Earth flyby and gravity assist on October 9, 2013, which is required in order to finally reach Jupiter and, assuming nothing goes wrong, achieve orbital insertion on July 5, 2016. Once in orbit, the spacecraft is scheduled to complete 33 highly elongated polar orbits, each lasting 11 days, making for a total primary mission duration of almost exactly one Earth year. At the end of the mission, Juno, by then likely exhibiting some degradation as a result of being exposed to the powerful radiation generated by Jupiter, will be crashed into the planet.
The mission goals are to look deep into Jupiter’s atmosphere to measure composition, temperature, cloud motions and other properties, including the amount of water present, while also mapping Jupiter’s magnetic and gravity fields and studying how the planet’s enormous magnetic force field affects its atmosphere. The probe may be able to determine whether Jupiter has a rocky core or it’s entirely made up of gases at increasingly higher pressures, its observations helping scientists narrow down the field of planetary formation theories, or perhaps come up with new ones if none of the existing ones seem to fit the new data. As a result, this mission is not only about Jupiter, but about advancing our knowledge regarding the formation of solar systems in general, whether we’re talking about our own or the countless others we’re discovering at an ever increasing pace.
Juno is also important because it is the first spacecraft that will use solar power at such a great distance. Unfortunately, unlike what can happen with those sent to the rocky planets, the damaging effect of Jupiter’s radiation means that using solar power won’t allow such missions to the giant planet to be extended far beyond the original plan. However, the fact that such a mission is possible at all proves not only that the approach is feasible, but also that solar power can be a very good solution even here on Earth. After all, to put things in perspective, Jupiter receives around 25 times less solar energy than Earth…
As a final “oddly enough” note, the mission planners managed to fit a few items inside the spacecraft that aren’t exactly required to achieve the mission objectives. I’m talking about a plaque dedicated to Galileo Galilei and three LEGO figurines depicting Jupiter, Juno and, of course, Galileo Galilei.