Probe launches after technical delay, on mission to get nearer to sun than anything sent before

A Nasa spacecraft is rocketing towards the sun on a quest to get closer to our star than anything ever sent before.

The Parker solar probe will fly straight through the wispy edges of the corona, or outer solar atmosphere, which was visible during last August’s total solar eclipse. It eventually will get within 3.8m miles (6.1m km) of the sun’s surface, staying comfortably cool despite the extreme heat and radiation, allowing scientists to explore the sun in a way never before possible.

“Fly baby girl, fly!” the project scientist Nicola Fox of Johns Hopkins University tweeted just before liftoff. She urged it to “go touch the sun”.

NASA (@NASA) 3-2-1… and we have liftoff of Parker #SolarProbe atop @ULAlaunch’s #DeltaIV Heavy rocket. Tune in as we broadcast our mission to “touch” the Sun: https://t.co/T3F4bqeATB pic.twitter.com/Ah4023Vfvn

Protected by a revolutionary new carbon heat shield, the spacecraft will zip past Venus in October. That will set up the first solar encounter in November. Altogether, the Parker probe will make 24 close approaches to the sun on the seven-year, $1.5bn (£1.2bn) project.

For the second day in succession, thousands of spectators jammed the launch site in the middle of the night as well as surrounding towns. A launch attempt on Saturday had been foiled by last-minute technical trouble.

Among the crowd was the 91-year-old astrophysicist Eugene Parker, after whom the spacecraft is named. He proposed the existence of solar wind – a steady, supersonic stream of particles blasting off the sun – 60 years ago.

It is the first time Nasa has named a spacecraft after someone still alive, and Parker was not about to let it take off without him being there.

“I’m just so glad to be here with him,” said Nasa’s science mission chief, Thomas Zurbuchen. “Frankly, there’s no other name that belongs on this mission.”

The Delta IV Heavy rocket thundered into the pre-dawn darkness on Sunday, thrilling onlookers. Nasa needed the 23-storey rocket, plus a third stage, to set the diminutive Parker probe – the size of a small car and weighing well under a tonne – racing toward the sun.

From Earth, it is 93m miles to the sun, and the Parker probe will travel 96% of that distance, getting far closer than any previous spacecraft.

Facebook Twitter Pinterest The rocket launch. Photograph: Bill Ingalls/AFP/Getty Images

Parker should start shattering records this autumn. On its first brush with the sun, it will come within 15.5m miles, easily beating the current record set by Nasa’s Helios 2 spacecraft in 1976. By the time Parker gets to its 22nd orbit of the sun, it will be even deeper into the corona, travelling at a record-breaking 430,000mph.

Nothing from Earth has ever hit that kind of speed.

“To me, it’s still mind-blowing,” Fox said. “Even I still go: ‘Really? We’re doing that?’”

By better understanding the sun’s nature, humans will be able to better protect satellites and astronauts in orbit and power grids on the ground, Zurbuchen said.

With this mission, scientists hope to unlock the many mysteries of the sun, a common yellow dwarf star that is about 4.5bn years old. Among them: why is the corona hundreds of times hotter than the surface of the sun and why is the sun’s atmosphere continually expanding and accelerating, as Parker accurately predicted in 1958?

Facebook Twitter Pinterest Astrophysicist Eugene Parker. Photograph: Kim Shiflett/AP

“The only way we can do that is to finally go up and touch the sun,” Fox said. “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.”

The spacecraft’s heat shield will serve as an umbrella, protecting the science instruments during the close solar junctures. Sensors on the spacecraft will ensure the heat shield faces the sun at the right times. If there is any tilting, the spacecraft is designed to correct itself so nothing gets damaged. With a communication lag time of 16 minutes each way, it is vital that the spacecraft can react to situations without human intervention, as the flight controllers in Laurel, Maryland will be too far away to help.

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A mission to get close up and personal with our star has been on Nasa’s books since 1958. A spacecraft small, compact and light enough to travel at incredible speeds was required, able to survive the sun’s punishing environment and an extreme change in temperature near Venus.

“We’ve had to wait so long for our technology to catch up with our dreams,” Fox said. “It’s incredible to be standing here today.”

More than a million names are aboard the spacecraft, submitted last spring by space enthusiasts, as well as photographs of Eugene Parker and a copy of his 1958 landmark paper on solar wind.

“I’ll bet you 10 bucks it works,” Parker said.