Juno set to reach farthest point in its Jupiter orbit

Five years after departing from Earth, NASA's Juno spacecraft is all set to reach the farthest point in its orbit of Jupiter on Sunday to "get the science" of the giant planet with a mass two-and-a-half times that of all the other planets in our solar system combined.

Known as "apojove", the orbit is nearly 8.1 million km from Jupiter, and after this point the gravitational grip of solar system's largest planet on Juno will cause the spacecraft to begin falling back toward it for another pass, NASA said on Friday.

"For five years we have been focused on getting to Jupiter. Now we are there, and we are concentrating on beginning dozens of flybys of Jupiter to get the science we are after," said Scott Bolton, Juno's Principal Investigator at the Southwest Research Institute in San Antonio.

Launched on August 5, 2011, Juno took a long, looping path around the inner solar system to set up an Earth flyby, in which our planet's gravity flung the spinning probe onward toward Jupiter.

Juno arrived at Jupiter on July 4 and is currently executing the first of two long orbits prior to beginning its science mission.

The spacecraft's science instruments were turned off during orbit insertion to simplify spacecraft operations during the flawless manoeuvre that allowed Jupiter's gravity to capture Juno into the first of two 53.4-day-long orbits, referred to as capture orbits.

Following the capture of 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, Juno must finish its first lap around Jupiter, with a finish line that represents the mission's closest pass over the gas giant. During the encounter, Juno will skim past Jupiter at a mere 4,200 km above the cloud tops.

"We are 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 Rick Nybakken, Juno Project Manager at NASA's Jet Propulsion Laboratory in California.

With its powerful suite of science instruments, Juno will probe Jupiter's deep structure, atmospheric circulation and the high-energy physics of its magnetic environment.

--IANS

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