US space agency NASA’s Juno spacecraft hit a milestone 55.46m kilometres (34.46m miles) from Earth at 4.25pm Irish time yesterday – the half-way point on its five-year journey to explore Jupiter.
“Juno’s odometer just clicked over to 9.464 astronomical units,” said Juno principal investigator Scott Bolton, of the Southwest Research Institute in San Antonio, Texas. “The team is looking forward, preparing for the day we enter orbit around the most massive planet in our solar system.”
An astronomical unit (AU) is based on the distance between Earth and the sun and is 149,597,870.7 kilometres (92,955,807.273 miles) long, NASA said. The 9.464 astronomical units is equivalent to 1,415,794,248 kilometres (879,733,760 miles).
Juno blasted off a year ago, on 5 August 2011. The spacecraft is expected to reach its next milestone in October, when it flies past Earth – as part of the orbit Juno is following in order to reach Jupiter – and gains more speed.
“On October 9, Juno will come within 559 kilometres (347 miles) of Earth,” said the mission’s project manager Rick Nybakken of NASA’s Jet Propulsion Laboratory in Pasadena, California.
“The Earth flyby will give Juno a kick in the pants, boosting its velocity by 16,330 mph (about 7.3 kilometres per second). From there, it’s next stop Jupiter.”
Juno is expected to arrive at Jupiter on 4 July 2016, at 7.29pm PDT/10.29pm EDT (5 July 2016 at 3.29am Irish time).
Once in orbit around Jupiter, Juno will circle the planet 33 times, from pole to pole, and use its eight instruments to probe beneath the gas giant’s cloud cover.
The goal is for Juno’s science team to learn about Jupiter’s origins, structure, atmosphere and magnetosphere, and to look for a potential solid planetary core, NASA said.
Jupiter image via Shutterstock