NASA’s Juno mission to Jupiter is now farther away from the sun than any other solar-powered mission in history. The new record was set on January 13, 2016, when Juno reached 493 million miles away from the sun. This incredible distance has previously only been traveled by nuclear-powered spacecraft.
The new milestone was made possible by three 30-foot-long solar arrays comprising 18,698 individual solar cells. These cells, made of silicon and gallium arsenide, are 50 percent more efficient and radiation tolerant than the solar technology that would have been available for space missions 20 years ago. These powerful cells could generate 14 kilowatts of electricity at Earth’s distance from the sun, but since Jupiter is five times farther away from the sun, the sunlight that hits the cells is 25 times less powerful, explained Juno’s project manager Rick Nybakken. He said, “While our massive solar arrays will be generating only 500 watts when we are at Jupiter, Juno is very efficiently designed, and it will be more than enough to get the job done.”
The mission will approach Jupiter on a path designed for maximum sun exposure while avoiding the planet’s high radiation regions, which could damage the scientific instruments on board. The four-ton spacecraft is carrying a gravity/radio science system, a six-wavelength microwave radiometer for atmospheric sounding and composition, a vector magnetometer, ultraviolet and infrared spectrometers, and other equipment. Therefore, Juno is carrying a unique radiation shielded electronics vault to protect these sensitive devices.
Juno is on track to arrive at Jupiter on July 4 of this year. The spacecraft will then orbit Jupiter 33 times over the next year. During this time, it will the atmosphere to examine the planet’s geology so that scientists can learn about the planet’s origin.
Source: NASA’s Jet Propulsion Laboratory
