PHOTO ESSAY

MISSION ICARUS

The is about to take us closer to the than ever before. It’s an audacious mission that will test technology – and the nerves of the scientists behind it – to the limit

Interviews by Richard Webb. Photos by Michael Soluri

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Our sun is no serene orb. Every now particles were moving very freely Previous page: The Parker Solar Above: A silver blanket covering the The doesn’t just break front surface, and we had to make and then its fiery surface turns from sun to Earth. Around the same Probe being tested at the Goddard probe will protect its instruments away from the sun, it carries the sun’s sure there would only be 30 watts explosive, sending matter, energy time, astronomers were noting that Space Flight Center in Maryland from the sun. One of its two solar magnetic field with it somehow. on the back side. There are some and magnetism whirling into the comet tails always pointed away panels will attach to the pair of Whatever state the field is in, whatever high‑temperature metals that could surrounding vacuum. from the sun, and that, too, was very Above: A mock-up of the mounts at the bottom of the shot direction, however strong it is, it is make the protective shield, but they In 1859, a particularly violent difficult to explain. instrument that will observe frozen into the solar wind. That’s what are too heavy to launch. solar flare-up coincided with a huge One day in 1958, it occurred to how electrons, protons and ions impacts Earth. When the activity’s The magic material is carbon. In electromagnetic storm in Earth’s me this was all very simple. The behave in the sun’s atmosphere high, that makes solar storms. the 1980s, you began to see carbon atmosphere. The interference caused sun’s atmosphere, the corona, is not Fears of a repeat of the 1859 storm – technologies in your golf clubs and auroras that could be seen as tightly bound. Stuff can escape, and one that might wreak havoc with The details of this process remained tennis rackets. In the early 2000s, we far south as the Caribbean and as the whole thing acts like one big modern power systems, satellites and enigmatic, and various missions took things one step further, making far north as Auckland, New Zealand, gaseous outward wind. It starts off communications networks – fuelled were planned to fly into the solar carbon materials light enough and and knocked out telegraphic systems. very slow, but gets faster and faster, a growing desire to take a closer look wind to investigate. In 1976, the strong enough to withstand the sun’s That was when we first grasped and by the time it’s out at Earth, it’s at the solar wind, says Parker Solar Helios-B spacecraft made it to heat, and coating them so they are the power of solar storms on Earth. supersonic. It sweeps cosmic rays to 6.2 Probe project scientist Nicola Fox. within 60 solar radii [or 42 million not so black and absorb less heat. But what caused them remained Earth – and blows the comet tails in million km kilometres] of the sun’s surface, Carbon is very brittle and fragile, unknown. In 1956, Eugene Parker, the opposite direction. The closest the Parker Solar The birthplace of the solar wind – the inside Mercury’s orbit. But there was and a lot of work went into making a young postdoc at the University of I came in for a lot of flak for the idea, Probe will get to the sun, or sun’s atmosphere or corona – must a fundamental technological barrier a heat shield that could survive the Chicago, was investigating cosmic but no one could find anything wrong about 10 solar radii away be super-energised. In fact, it must to getting any closer: no material launch environment. When we finally rays arriving at Earth from far off in with the mathematics. Then, in 1962, be 300 times hotter than the sun’s existed that was lightweight yet thought we had a solution, we went the galaxy when an idea struck him. they launched Mariner 2 to Venus, surface. That defies the laws of heat‑resistant enough to shield the back to NASA and NASA said, OK, go the first mission into interplanetary nature: you shouldn’t have a heat probe’s instruments from the sun, forward, you’re now a mission. We knew cosmic rays were correlated space. What it saw could hardly be source that gets hotter as you move says engineer Andy Driesman. with the sun’s magnetic activity, but denied. The transformation was very 1400ºC away from it. There’s some additional The Solar Probe Plus mission, the timing of the cosmic rays on our quick: people were saying we always The temperature the probe energy, some black magic going on in As close to the sun as we wanted to approved in 2009, looked very detectors during one particularly knew there was a solar wind. You will feel on its sun-facing this region, and it’s causing the solar get the probe, there would be almost different from previous proposed violent solar flare showed that the know how it goes. I never criticised. side at its closest approach wind to say, I’m off. 3 million watts of heat energy on its sorties to the sun. That was down to >

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circular route o et within the suns atoshere the arer Solar robe will hae to loo round enus seen ties usin the lanets rait to slow it down so it can all into orbit around its taret

Sun

Earth Mercury Venus First closest approach 1 November 2018 Closest approach (2024-25) First Venus flyby 28 September 2018

Parker Solar Probe flyby multiple times, each time losing there in the solar wind, we will be closer each time. With each pass, closest approach Sun’s surface Helios-B, previous closest approach 17 April 1976 6.2 million km some velocity and falling in closer to able to measure it directly, and all the its measurements of fluctuating the sun, but that means manoeuvring speculation will be over. magnetic fields and fast-moving to pass Venus in the right orbit each charged particles in the sun’s corona Earth Venus Mercury Sun’s centre Approximate edge of time, which is tricky and uses up fuel. The probe is scheduled for launch will give us further insights into what the sun’s atmosphere Eventually, I found a trajectory with on 31 July – the tensest time for the makes the solar wind. That’s when seven Venus assists that passes the mission team, says Andy Driesman. things get interesting, says Nicola Fox. sun 26 times, each time closer. The closer the probe falls, the faster it gets. It’s like having a baby. You read the The most exciting thing will be our first a shortage of plutonium radioisotope to get to Mars. It’s more than twice Above: To get within the sun’s At its fastest, it will be travelling at books and you see the kids around closest approach. Even though it won’t fuel for nuclear-powered spacecraft, even what you need to get to Pluto. atmosphere, the probe will have 200 kilometres a second – the fastest you, so you know how it’s done and be at the ultimate goal of 10 solar which led NASA to favour purely For five decades, we had been o loop round Venus seven times, spacecraft ever. what to expect, but nothing prepares radii – it will be out at about 35 solar solar‑powered missions – and studying this problem on and off, using the planet’s gravity to slow you for that moment. You have built radii – it is still way closer than anyone ironically that becomes a particular and had come to the same conclusion: it down so it can fall into orbit In May 2017, NASA renamed the this thing, you have designed it, you has been before. We are going to be problem when you want to visit the to get to the sun you need a Jupiter around the sun. The different probe after Eugene Parker. Now have tested the heck out of it and then in uncharted territory, a “here be sun. Mission scientist Yanping Guo gravity assist. Instead of going directly orbital periods mean the probe has 90 years old, he became the first you launch it. You are in the hands of dragons” space. Just that is exciting – to had to find a way to solve it. to the sun, you launch out to Jupiter, to go round the sun several times living scientist to be so honoured. a fiery beast and you have 60 minutes be somewhere no one has been before. and use its gravity to reduce the between gravity assists, getting with no control whatsoever. And then Even so, the idea of never seeing her When you launch a spacecraft from spacecraft’s speed so it falls inwards. closer to its target each time I was invited to have a look at it. It’s you make first contact after launch again is traumatic. It’s a little bit like Earth, it possesses Earth’s orbital But at Jupiter’s distance, solarCOPY SUB quite a monstrosity. When I came out and you catch a breath of relief because sending your kids to college – you velocity, about 30 kilometres a power won’t work: you need nuclear. with the theory 60 years ago, I never now you’ve got control again. You can have brought them up and all you second. To get to the sun, you have to Everyone said the problem wasPAGE SUB Photos, clockwise from above: thought about whether it would be talk to the thing, you can understand can do now is hope you have brought ■ cancel out most of that, slow it down impossible, but I started lookingOK at for pressNicola Fox, project scientist for possible to get that close to the sun, what is going on. them up right, and hope they write. so it can fall in under gravity.G_Solar_orbiter_line That whether you might use the gravity the probe. Test engineer Annette because I didn’t know what the limits takes a lot of energy. If you want to of the inner planets instead. Venus Dolbow. Yanping Guo, who devised were. But after those years of people After it arrives at the sun in November, Richard Webb is New Scientist’s chief launch directly from Earth to the sun, is much smaller than Jupiter, so its the novel trajectory for the probe. being sceptical at the beginning, I feel the probe will fly past it a further features editor. Michael Soluri is a freelance you need 55 times more energy than gravity assist is much less. You can Andy Driesman, engineer very good. With instruments right up 25 times over seven years, getting photographer based in New York

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