Juno Mission Feels Jupiter's Gravitational Hug
When we send spacecraft into the solar system, they feel the gravitational pull of the sun and the planets. Space scientists will even use the gravity of the planets to sling-shot their robotic spacecraft into deep space.
In the case of NASA's next mission to Jupiter, which has been coasting through space since its launch on Aug. 5, 2011, it has used Earth as a valuable gravity boost and been guided on its orbit by the sun's gravitational field. But as of tomorrow, the most dominant gravity Juno will feel will be Jupiter's and it will stay that way until its mission ends.
"Today the gravitational influence of Jupiter is neck and neck with that of the sun," said Rick Nybakken, Juno project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif., in a NASA news release. "As of tomorrow, and for the rest of the mission, we project Jupiter's gravity will dominate as the trajectory-perturbing effects by other celestial bodies are reduced to insignificant roles."
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In other words, Jupiter is all there is for Juno from here on in; the gravities of other celestial bodies, particularly the sun, will fade into nothing more than a distant whimper and Jupiter will now be in the orbital driving seat.
This gravity "handover" is the beginning of some big changes for Juno. On July 4 it will commence its orbital insertion maneuver around the gas giant, carrying out a jarring 35 minute main engine burn that will slow the speeding spacecraft down by 1,212 mph (or 542 meters per second), allowing Jupiter's gravity to guide Juno into its new orbital home. But this isn't a comfortable new home -- the orbit of Jupiter is wrought with radiation hazards and, though Juno has some complex shielding, this will inevitably take its toll and ultimately puts a shelf-life on the mission's duration.
Its primary mission will see Juno orbit Jupiter 37 times, coming within 3,100 miles of the planet's cloud tops. The mission will make incredibly precise measurements of the planet's atmosphere and magnetic field, probing into the underlying physics of Jupiter's supercharged auroras. This is all in an effort to understand how this planetary giant formed and evolved into its current state.
But as with all missions deep within the solar system, we're also looking back on ourselves, trying to piece together the giant jigsaw puzzle about how Earth formed in the way that it did and, ultimately, add another layer of understanding as to how life -- particularly life intelligent enough to propel robots across interplanetary space -- was sparked.
Since NASA's Galileo mission, which ended in 2003, we haven't had a spacecraft at the gas giant. Now that's soon to change and it's exciting to anticipate what incredible science Juno will uncover.