NASA today sent a super-shielded spacecraft known as the Parker Solar Probe on a mission that will take it closer to the sun than any other spacecraft has flown, with the probe’s namesake, a 91-year-old physicist, watching the launch.
A blazing United Launch Alliance Delta 4 Heavy rocket rose into the night sky from its launch pad at Cape Canaveral Air Force Station in Florida at 3:31 a.m. ET (12:31 a.m. PT), one day after concerns over a data glitch forced a postponement.
Three rocket stages powered the probe on the first leg of its sunward journey.
“All I can say is, wow, here we go, we’re in for some learning over the next several years,” University of Chicago solar physicist Eugene Parker said just after liftoff.
The car-sized observatory is designed to endure temperatures of up to 2,500 degrees Fahrenheit as it flies within 4 million miles of the sun’s surface. That’s almost 10 times closer than Mercury gets, and seven times closer than any previous probe.
Its maximum velocity around the sun will reach 430,000 mph, making it the fastest human-made object to orbit a celestial body.
Scientists hope to shed light on the workings of our closest star — including the dynamics of the solar wind of electrically charged particles, and the reason why the sun’s outer atmosphere, or corona, is hundreds of times hotter than the sun’s surface.
“The only way we can do that is to finally go up and touch the sun,” the $1.5 billion mission’s project scientist, Nicola Fox of Johns Hopkins University’s Applied Physics Laboratory, told reporters in advance of today’s launch. “We’ve looked at it, we’ve studied it from missions that are close in — even as close as the planet Mercury — but we have to go there.”
It’s been 60 years since Parker came up with the theory behind the solar wind and the strong outbursts that can cripple communications and electric grids on Earth. But it’s only been in the past few years that scientists and engineers could put together a space mission capable of going close enough to get the data to back up the theory.
“We’ve had to wait so long for our technology to catch up with our dreams,” Fox said.
The Parker Solar Probe won’t touch the sun’s surface, but it will monitor its electric and magnetic fields as well as the flow of plasma and solar-wind particles through the corona. The probe’s instrument payload also includes a white-light camera that will take the kinds of pictures of the shimmering corona that are seen on Earth only during a total solar eclipse.
Over the course of nearly seven years and 24 solar orbits, the probe will make use of seven Venus flybys to adjust its trajectory. “We actually slow down just a little bit, and that allows us to shrink our orbit,” Fox explained.
The spacecraft is equipped with a 4.5-inch-thick, 8-foot-wide carbon composite shield that should keep the electronics at their proper operating temperature even amid temperatures that would melt aluminum. The probe’s power-generating solar arrays are water-cooled to keep them from overheating.
Eventually, the probe will run out of fuel for its thrusters and lose its protective orientation. When that happens, the sun’s heat will turn it into a fried disk of carbon, and then break it down even further into flecks of debris. But if the mission goes as planned, the probe’s discoveries will serve as a lasting legacy to Eugene Parker, the only living person to have a NASA spacecraft named after him.
“I really have to turn from biting my nails and getting it launched to thinking about all the interesting things which I don’t know yet, and which will be made clear, I assume, over the next five or six or seven years,” Parker said. “It’s a whole new phase, and it’s going to be fascinating throughout.”