Like the jealous Roman goddess of women, the NASA spacecraft Juno flies through the heavens to keep an eye on her unfaithful husband, Jupiter. Launched Aug. 5, 2011, Juno is well on her way to her destination and is expected to rendezvous with Jupiter in 2016.
Last Tuesday, Bill Hubbard, planetary sciences professor at the UA and co-investigator on the Juno mission, gave the first of many evening talks this fall hosted by the UA Lunar and Planetary Laboratory. He discussed Juno’s goals, obstacles and legacy.
NASA researchers hope to learn about the formation of Jupiter, its hidden inner core, the depth of its violent storms and its powerful magnetic field, among many other things.
Over the last 20 years, according to Hubbard, we’ve learned of the existence of many Jupiter-sized planets orbiting other stars within our galaxy. “Juno will give us an archetype for these larger planets,” Hubbard said.
Scientists think Jupiter was the first planet to form because of its great size and gaseous makeup. Investigators hope to find that it has preserved material from the composition of the young solar system, giving us further insights into how other planets formed.
Juno is also the first completely solar powered spacecraft as the others have all been nuclear powered. The three solar panels are very large because less sunlight reaches Juno as she flies deeper into the solar system.
Many ask, “Why go back?” But Juno is actually the first mission to get a close range view of the nearest Jovian planet in our solar system.
“We did have one space craft, Galileo, that orbited Jupiter for eight years” said Tim Swindle, department head and director of LPL. However, damage to the main antennae restricted the amount of data it could send back and “the people running the mission made the choice to focus on the moons of Jupiter.”
Jupiter is also a dangerous place for space probes. The gas giant has a faint ring system which might cause collisions with the probe; but the radiation belts created by Jupiter’s gigantic magnetic field are an even more powerful adversary.
The probe must avoid the high energy particles captured and concentrated by these arching bands of Jupiter. To put it in perspective, by the end of the mission, according to Hubbard, Juno will receive the equivalent of 100 million dental X-rays.
NASA planned a special orbit for the probe because of these factors. Even so, Juno will only be able to circle Jupiter about 30 times before the radiation exposure from these belts causes too much damage.
At the end of her mission, Juno will fall from orbit into the gas planet leaving an “incandescent path” as it burns up in Jupiter’s thick atmosphere, Hubbard said.
NASA wants to do everything it can to avoid contaminating Europa, one of Jupiter’s moons, because they believe it is the most likely place to harbor life in our solar system.
Some see this summer’s flyby of Pluto as the end of an era in planetary exploration. However, Swindle points out that flybys are only the first step in planetary exploration. He sees it as a logical profession of flyby, orbiter, lander, sample return and then human exploration.
“Not every place will be a place where humans will want to go … but we’ll keep learning about things we hadn’t guessed and keep learning more about how the Earth fits in,” Swindle said.
The principal investigator, Scott Bolton, has two sons that were “very much into Legos. So Scott arranged a deal with the Lego [Group] to include some things on the spacecraft,” Hubbard said.
There are “special passengers” hitching a ride to the gas giant: three little Lego men covered in aluminum alloy and bonded to the deck of the spacecraft. The first is Jupiter grasping a lightning bolt, the second is Juno holding a magnifying glass and the last is Galileo with his telescope as a “tribute to our Italian partners” on the mission, Hubbard said.
This was the first lecture in the LPL’s Evening Lecture Series. A calendar of future lectures is available on their website, along with audio recordings of previous lectures.
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