An Ocean of Air (30 page)

But this still left the intriguing question: How exactly was the sun achieving this? Appleton wanted to know what made the Heaviside layer.

On June 29, 1927, he got his chance to find out. For on that day a solar eclipse was to take place, with the moon passing in front of the sun and blocking its rays from Earth's view. The moment the sun's rays were stopped, would it be like dusk? And when they returned, would the Heaviside layer deepen as if at dawn?

The eclipse would take place early, about 5:00 in the morning. Appleton persuaded the ever-obliging BBC to send out special transmissions from Birmingham for him to pick up at Peterborough. He also talked ships' captains into limiting their transmissions to emergencies for the duration of his experiment, to keep the airwaves free. Sunrise came on the twenty-ninth, and with it the familiar lowering of the Heaviside layer as the sun's rays slowly appeared. Then the time for the eclipse approached. The moon's shadow began to shroud the atmosphere above Peterborough, and immediately the reflected radio wave grew stronger and the Heaviside layer lurched upward.

The effects at dawn and dusk had always been gradual, reflecting almost imperceptible changes as the sun's rays gradually spilled over the horizon. But now, with this solar eclipse, there was no delay. The effect was instantaneous.

That, to Appleton, could mean only one thing. Whatever was doing the electrification had to travel earthward at the speed of light. No particles can travel that fast—it had to be some kind of light rays. And Appleton correctly surmised that the culprit must be among the most energetic such rays in the universe: x-rays.

This was the answer he had been looking for, the explanation for why Heaviside's mirror was present in the sky. But more than that, it revealed for the first time the powerful role that this mirror plays in all our lives. Because the same process that electrifies the air also protects us from a horrifying menace.

X-rays from space are deadly, because they can do to living cells precisely what they do to the atoms high in the ionosphere. Incoming x-rays arrive with such extraordinary energy that they can smash DNA molecules into their electrical fragments, triggering the onset of cancer. That's why we have to be so careful about medical X-ray doses.

X-rays are so energetic that it takes only a smidgeon to allow us to see through biological tissue and pick out the body's internal organs and bones. So there's not much to worry about in a hospital—it would take
45,000 simultaneous chest x-rays to kill you. But outside the ionosphere's protection, that kind of blast can happen in an instant. The sun throws them out all the time. Just one solar outburst of x-rays, and any creature that is not sheltering beneath the ionosphere would be fried. The International Space Station contains a specially reinforced module to protect the inhabitants from this danger. If the sun flares up, astronauts must immediately rush to the module and take cover.

With his eclipse experiment, Appleton had discovered that the ionosphere was much more important than a mere conduit for communications. It forms yet another sacrificial layer of air. By allowing its atoms to be shattered, it protects us from the x-rays that continually bombard our fragile planet.

***

Appleton's fame was now assured, and the conventional high honors came his way. He was knighted by the king. He received the U.S. Medal of Merit, the Officership of the French Legion of Honor, and was even appointed by the pope to the Pontifical Academy of Science. Like Marconi, and unlike Oliver Heaviside, Appleton also received the Nobel prize for physics. In his later years, Appleton became an illustrious university administrator, spending much more time in committees than he managed in the lab. He became more establishment than ever, but his conservatism still came with a twist. His younger daughter, Rosalind, exhibited a "slight naughtiness" that made her a favorite with her father. He was delighted when, dissatisfied with a drink served her at a hotel, she calmly topped it up from a bottle of gin that she had withdrawn from her straw shopping basket.

And whenever he could, Appleton would sneak away to collect data or analyze results. He talked about his research as "escape into the upper atmosphere." He spent the rest of his life trying to understand how the ionosphere worked.

One of his most intriguing, and baffling, findings had come back in the 1930s during an expedition to the Arctic. Appleton had wanted to investigate how the ionosphere was affected by magnetic disturbances, which were known to be strongest near the poles. So he arranged to take
measurements from Tromso, in the far north of Norway. While he was there, Appleton discovered that there seemed to be a connection between the ionosphere and magnetic storms. When a storm arrived to set compass needles swinging, the ionosphere blacked out. Electricity and magnetism were obviously working in some kind of tandem.

Though Appleton didn't figure out exactly how these two forces cooperate in the air above our heads, he was certainly on the right track. For the final protective layer of the atmosphere is indeed driven by a cooperative effort between the electricity of the ionosphere and the magnetism above it. Thousands of kilometers above Earth's surface, where the air is so thin it is scarcely there at all, sweeping lines of force from the planet's own magnetic field act as sentinels for one final threat from space, while below the ionosphere is waiting to catch this threat and disarm it.

This threat is the most dangerous of all, and yet we were unaware of it until the 1950s, at the very dawn of the space age.

OCTOBER
4, 1957
U.S.S. GLACIER
SOMEWHERE IN THE VICINITY OF THE GÁLAPAGOS ISLANDS

Yesterday night the
4
th and early this morning were very exciting for me (as well as for the civilized world in general).

Just before dinner time Larry Cahill told me that news was just coming in on the ship's news circuit that the
Soviet Union had successfully launched a satellite.
Factual details as follows:

Inclination of orbit 65 degrees to earth's equator. Diameter 58 cm, Weight 83.6 kilograms (Wow!), Estimated height 900 kilometers. Period ih 35m

***

JAMES VAN ALLEN
had always been assiduous at keeping his field notebook, and this one was no exception. It was neatly labeled "Equatorial-Antarctic Expedition," and every entry was carefully dated. The expedition had barely begun; the ship had only just passed through the Panama Canal. Still, Van Allen usually started his notebook as soon as he sailed, to take note of any little incidents that might be important later. He hadn't expected to be writing anything as exciting as this, and certainly not so soon.

Van Allen ate his dinner. He watched a second-rate movie. But he couldn't contain himself; even out here in the middle of the ocean, he needed to know more. Off he headed to the communications shack, where a young radioman was already seated, wearing a set of headphones and
hovering over a receiver. "I think I have it," he said. Van Allen took the headphones and listened for himself. There it was, loud and clear: "Beep-Beep-Beep." It was incredible to believe that this was an artificial satellite, launched by human hand and ingenuity, announcing its presence as it passed sporadically above the ship with this regular, disciplined cheeping. It was so unlike the natural—erratic—sounds of the atmosphere, and so exactly what Van Allen had been wanting to hear for years.

He had been saying since 1948 that humankind could put a satellite into orbit. The
New York Times
had mocked him; the
New Yorker,
even, had poked its own brand of gentle fun. He had been forced to remove that part of his speech at a major conference as being "too speculative." And now there it was, Beep-Beep-Beep, right above their heads.

Immediately, Van Allen wanted a recording. But the tape recorder down in his lab was way too bulky, and besides, it was built so completely into the other apparatus that it would take too long to free. By now another passenger was in the communications room—John Gniewek, from the U.S. Coast and Geodetic Survey, who would be operating a magnetometer station in Antarctica for the next year. Gniewek had a small magnetic tape recorder in his room—he could easily fetch it, he said. While Gniewek did this, Van Allen tumbled downstairs to fetch his oscilloscope. What would it look like, this first human signal coming down to us from space? Van Allen noted the shape down in his notebook: a flat line punctuated by a periodic thicket of scribbles, as if an unruly child were grabbing the pencil every 0.2 seconds, for precisely 0.3 seconds at a time.

The communications shack was getting crowded now as more members of the expedition arrived. They took turns listening to the next pass, and the one after, and the one after that. Finally, at 2:00 in the morning, Van Allen headed off to bed. He had rarely written so many exclamation points in his field notebook. And the last one for the day was perhaps the most significant: "Very great thrill!"

"The dawn of the space age!" screamed newspaper headlines around the world. London's
Daily Mirror
changed its header. No longer the "biggest daily sale in the world," it had become the biggest "in the UNIVERSE."

News had come quickly to Washington. As luck, or more probably, design, would have it, scientists from the Soviet Union, the United States, and five other nations had gathered at the National Academy of Sciences to discuss rocket and satellite activities for the International Geophysical Year, which was currently underway. A member of the Soviet delegation, Sergei M. Poloskov, had already caused jitters by suggesting that the world was on the eve of the first artificial earth satellite. And now, there it was. Walter Sullivan, from the
New York Times,
had received a call from his desk editor. Immediately he had rushed over to one of the U.S. attendees. "It's up!" he had whispered. The attendee threaded through the crowd to relay the news to the official U.S. delegate for the meeting, one Lloyd Berkner. Berkner called for silence. "I wish to make an announcement," he said. "I've just been informed by the
New York Times
that a Russian satellite is in orbit at an elevation of 900 kilometers. I wish to congratulate our Soviet colleagues on their achievement."

America, of course, was thunderstruck. At first there was silence, and then the jokes came, followed quickly by recriminations. Bars around the country began selling "Sputnik cocktails"—one-third vodka and two-thirds sour grapes. And everybody wanted to know how in the hell the Russians had got there first. The United States was the country of technological innovation. It was the country that had pioneered flight, and had been leading the world for decades. How had the American satellite program been caught, as one sour punter remarked, "with its antennas down"?

There was no shortage of theories. Coming as it did on the coattails of the McCarthy era, some said the witch-hunting of scientists was the problem. Others laid the blame higher. Hadn't the president himself talked repeatedly of scientists as "just another pressure group"? Hadn't presidential aide Sherman Adams talked disparagingly of "an outer space basketball game"? There was only one thing that everyone was clear about: Americans needed a riposte, and they needed it fast.

Vanguard was the name of the official U.S. satellite program. After a dreadful summer of technical hitches, the project team was about to get its first full rocket off the ground. But the upper two stages of the rocket were
to be dummies. And nobody was interested any more in tests. What they needed was a
satellite.

The program's director, John Hagan, did his best to explain to the president the current state of play. They had another launch scheduled for December that year, and yes, this time it would be a complete rocket—no dummy stages. It would also carry a minimal payload—a satellite, if you like, weighing four pounds. However, this was not, repeat
not,
a mission flight. It was designed merely to test the launch vehicle. Putting the satellite into space from this flight would, said Hagan, be "a bonus."

On October 9, the presidential press office informed reporters that, in two months' time, Project Vanguard would launch a "satellite-bearing vehicle."

Now the pressure really began to rise. Early in November, the Vanguard test rocket, known as TV-3, made its way to launch complex 18A at Cape Canaveral in Florida. For the next four weeks, all tests went smoothly. The engineers were cautiously optimistic, even though the crowds who had started to arrive at the Cape were making them uneasy. This was supposed to be a
test,
done under carefully controlled conditions, with a bit of peace and quiet. But the president's announcement had put paid to that. Word had got around that this was America's attempt to put a satellite in space. And everybody wanted to be a witness.

Or almost everybody. Hagan had decided to stay in Washington to keep an eye on events there. His deputy, Paul Walsh, would let him know exactly what was happening on the ground.

The
New York Times
was at the scene, of course. "Last night," its reporter wrote on Sunday, December 1, "from one of the coarse sandy beaches where the 'bird watchers' of the missile age watch the Cape Canaveral spectacles, the Vanguard Tower was clear against a starry sky, two bright white lights glaring at its base and a red beacon shining at its top." It was certainly an impressive sight: the white rocket, nudged up against its giant gantry crane, pointing to the sky. People had arrived from all over America, and even from Europe. As the days advanced, the excitement of the crowds only mounted as one delay after another halted the countdown clock. Launch had been scheduled for Wednesday, then
Thursday. But finally, by the morning of Friday, December 6, at 10:30, there were only sixty minutes to go.

T
-45.
The radio tracking network began sending in its "all clear" signals.
T
-30,
and a klaxon sounded warning all nonessential personnel to leave the area.
T
-25,
and the heavy doors of the blockhouse swung shut.
T
-19,
the blockhouse lights were now out.
T
-5,
and the voice reading the countdown had the faintest of tremors.
T
-i,
and the count had switched to seconds. The rocket fired, the engines lit with an unspeakable roar. And...