[Image above] Credit: NASA Jet Propulsion Laboratory; YouTube
While those of us in the United States stare awestruck at the firework-filled night sky on July 4 in celebration of our nation’s independence, NASA’s Juno spacecraft will finally reach polar orbit around Jupiter—a long-awaited journey from when Juno launched on Aug. 5, 2011 from Cape Canaveral, Fla.
Since that launch, NASA has tracked Juno’s progress as it travels to our solar system’s largest planet.
“On the evening of July 4, Juno will fire its main engine for 35 minutes, placing it into a polar orbit around the gas giant. During the flybys, Juno will probe beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet’s origins, structure, atmosphere, and magnetosphere,” explains a recent NASA press release.
But getting this close to Jupiter doesn’t come without serious high-stakes risks.
“We are not looking for trouble, we are looking for data,” Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio, Texas, says in the release. “Problem is, at Jupiter, looking for the kind of data Juno is looking for, you have to go in the kind of neighborhoods where you could find trouble pretty quick.”
Those “neighborhoods” Bolton refers to include a layer of hydrogen under such high pressure it acts as an electrical conductor. Scientists believe that the combination of this hydrogen layer along with Jupiter’s fast rotation—one day on Jupiter is only 10 Earth hours long—generates a powerful magnetic field that surrounds the planet with electrons, protons, and ions traveling at nearly the speed of light, the release explains. So Juno stands to encounter some of the harshest radiation in the solar system the closer it gets.
“Over the life of the mission, Juno will be exposed to the equivalent of over 100 million dental X-rays,” Rick Nybakken, Juno’s project manager from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., adds. “But, we are ready. We designed an orbit around Jupiter that minimizes exposure to Jupiter’s harsh radiation environment. This orbit allows us to survive long enough to obtain the tantalizing science data that we have traveled so far to get.”
And Juno’s construction is made to stand up to the harshness of deep space.
“While Juno is replete with special radiation-hardened electrical wiring and shielding surrounding its myriad of sensors, the highest profile piece of armor Juno carries is a first-of-its-kind titanium vault, which contains the spacecraft’s flight computer and the electronic hearts of many of its science instruments. Weighing in at almost 400 pounds, the vault will reduce the exposure to radiation by 800 times of that outside of its titanium walls,” the release explains.
Powering Juno is an electrical source not often used in deep space missions: solar arrays.
Juno is equipped with more than 18,000 solar cells located on 11 panels—four of those panels are attached to each of two of the spacecraft’s 250-pound wings, explains a NASA article from 2011 that outlines the construction of the spacecraft. A third wing has three panels and is outfitted with a boom at the end that carries the spacecraft’s magnetometer.
“In general, once we’re out at Jupiter, we need 405 watts, which is not really enough to even run your hair dryer,” Russ Gehling, the solar array subsystem’s lead engineer with Lockheed Martin, says in the article. “Of those 405 watts, about half of them go toward keeping the spacecraft warm. So, the other half, somewhere in the 250 range, is to run all of the instruments and all of the avionics.”
Check out this recently released video from NASA, Jupiter: Into the unknown, to learn more about Juno’s mission.
Credit: NASA Jet Propulsion Laboratory; YouTube
And to keep tabs on Juno’s whereabouts, follow the spacecraft on Twitter.