Almost a month after slipping into orbit around the Solar System’s largest planet, NASA’s Juno spacecraft is nearing a turning point.
Juno. Image credit: NASA / JPL.
Today, July 31, at 12:41 p.m. PDT (3:41 p.m. EDT, 7:41 p.m. GMT), Juno will reach the farthest point in its orbit of Jupiter for the first time, known as ‘apojove.’
After that point, 5 million miles (8.1 million km) from the gas giant, Jupiter’s gravitational grip on Juno will cause the solar-powered spacecraft the size of a basketball court to begin falling back toward the planet for another pass, this time with its scientific eyes wide open.
“We’re in an excellent state of health, with the spacecraft and all the instruments fully checked out and ready for our first up-close look at Jupiter,” said Juno project manager Dr. Rick Nybakken, from NASA’s Jet Propulsion Laboratory.
“We’re concentrating on beginning dozens of flybys of Jupiter to get the science we’re after,” added Juno principal investigator Dr. Scott Bolton, from Southwest Research Institute.
Juno arrived at Jupiter on July 4, firing its main rocket engine as planned for 35 minutes.
The flawless maneuver allowed Jupiter’s gravity to capture the spacecraft into the first of two 53.4-day-long orbits, referred to as capture orbits.
This diagram shows Juno’s orbits, including its two long, stretched-out capture orbits. The spacecraft’s position on July 31 is indicated at left. Image credit: NASA / JPL-Caltech.
Following the capture orbits, Juno will fire its engine once more to shorten its orbital period to 14 days and begin its science mission.
But before that happens, on August 27, the spacecraft must finish its first lap around Jupiter, with a finish line that represents the mission’s closest pass over the planet.
During the encounter, Juno will skim past Jupiter at a mere 2,600 miles (4,200 km) above the cloud tops.
Juno’s science instruments were turned off during orbit insertion, to simplify spacecraft operations during that critical maneuver.
In contrast, all the instruments will be collecting data during the August 27 pass, which serves as a trial run before the mission gets to work collecting the precious data it came for.
During its mission of exploration, Juno will circle Jupiter 37 times.
It is the first spacecraft to orbit the gas giant since NASA’s Galileo orbiter, which deliberately crashed into Jupiter in September 2003.
