This artist’s rendering shows NASA’s Juno spacecraft making one of its close passes over Jupiter: NASA/JPL-Caltech

By Glynn Wilson –

As Americans party by the water, gorge on barbecue and take in the fireworks shows on the Fourth of July 2016, space scientists from Florida to California will be consuming coffee and staring at computer screens waiting to see if the Juno probe will successfully enter the volotile atmosphere of Jupiter.

At stake is a $1 billion mission to look through the dense atmosphere of the solor systems largest planet to map its gigantic magnetic field and gather data on its origins by exploring its water.

Confirmation is expected Monday night around 11:53 p.m. Eastern Standard Time.

“At this time last year our New Horizons spacecraft was closing in for humanity’s first close views of Pluto,” Diane Brown, Juno program executive at NASA Headquarters in Washington, said in a news release about the event. “Now, Juno is poised to go closer to Jupiter than any spacecraft ever before to unlock the mysteries of what lies within.”

Launched from Florida nearly five years ago, the Juno craft’s position on approach must be precise. Ignition of the main engine must come at exactly the right time and it must burn for 35 minutes to hit the right speed to be captured by Jupiter’s gravitational field. If anything goes wrong, the craft could sail helplessly past the ringed planet and hurtle ever deeper into the Milky Way galaxy.

“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, said 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.”

The source of potential trouble can be found inside the planet. Well below the Jovian cloud tops is a layer of hydrogen under so much pressure it acts as a powerful conductor of electricity. NASA scientists believe that the combination of this metallic hydrogen along with Jupiter’s fast rotation will generate a powerful magnetic field, exposing Juno to the harshest radiation environment in the solar system.

“Over the life of the mission, Juno will be exposed to the equivalent of over 100 million dental X-rays,” said Rick Nybakken, Juno’s project manager from NASA’s Jet Propulsion Laboratory in Pasadena, California. “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.”

Juno, a solar-powered spacecraft the size of a basketball court, orbits in a pattern resembling a flattened oval. The trajectory of approach will be over Jupiter’s north pole. It will then drop fast to an altitude below the planet’s radiation belts as it approches the south pole.

If all goes well, 37 approaches are planned. To bolster it against the radation, the craft it equipped with radiation-hardened electrical wiring and shielding surrounding its sensors, along with a 400-pound titanium vault housing the spacecraft’s flight computer and electronic instruments.

Without the vault, Juno’s electronic brain would fry before the end of the very first flyby. The special orbit allows the radiation dose and the degradation to accumulate slowly, hopefully allowing the craft to accomplish its research mission. Stay tuned.

NASA’s Juno spacecraft obtained this color view at a distance of 6.8 million miles (10.9 million kilometers) from Jupiter, on June 21, 2016: NASA/JPL-Caltech

More information on the Juno mission is available at this link.