Juno spacecraft recovers from fault after Earth flyby
BY STEPHEN CLARK
Posted: 14 October 2013
Scientists in charge of NASA's Jupiter-bound Juno mission said Friday the speedy spacecraft recovered from a fault that triggered an unexpected safe mode as it zoomed by Earth for a gravity assist flyby Wednesday.
Juno exited safe mode at 5:12 p.m. EDT (2112 GMT) Friday, according to SWRI.
Racing away from Earth after a slingshot maneuver to gain speed, Juno is on the way to an encounter with Jupiter on July 4, 2016, to begin a one-year investigation of the giant planet's magnetic field, atmosphere and internal dynamo.
Wednesday's flyby of Earth was planned before Juno's launch in August 2011 because its launch vehicle was not powerful enough to send the spacecraft on a direct journey to Jupiter.
The Earth flyby increased Juno's velocity by more than 16,000 mph, bending its trajectory to carry the probe out to Jupiter's orbit for arrival in less than three years.
Juno's closest approach to Earth, about 350 miles over the Indian Ocean near South Africa, occurred when the spacecraft was out of range of ground stations. But when a European Space Agency antenna in Australia picked up a signal from Juno a few minutes later, controllers noticed the spacecraft put itself in an automated fault-protection status known as safe mode.
In safe mode, the spacecraft deactivated its science instruments and turned toward the sun to ensure its batteries remained charged.
Officials said most of the images and data expected from the flyby were collected and downlinked to Earth before Juno initiated safe mode.
Scott Bolton, Juno's principal investigator from SWRI, said the $1.1 billion mission's science team planned to use data gathered during the flyby for calibration of the craft's instruments and as a simulation for mission operations once Juno reaches Jupiter.
The spacecraft's main camera, named JunoCam, also took pictures of Earth during the flyby. Raw images from JunoCam are available online for processing by amateurs and enthusiasts, making the camera an outreach tool for public relations and education.
And Juno acquired images during approach for scientists to stitch together into a movie of the Earth and moon, showing the moon circling the planet in an unprecedented vista from deep space, Bolton said.
"It will be very different from anything any human has ever seen before," Bolton said.
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