Read from Chapter 1, "Aboard the Glacier" in Ambassadors from Earth: Pioneering Explorations with Unmanned Spacecraft by Jay Gallentine:

"Larry Cahill sardined himself into the communication shack with James Van Allen, who had headphones popped over his ears. It was quite hot and late at night. Both were thankful that they could be near the top of the ship, because that was farthest from the blistering engine room.

“Well, I wonder if that could really be it,” Van Allen said to nobody in particular. There was this inexplicably goofy beep-beeping sound in the headset. Something didn’t add up here. He glanced around. On the assembled faces were looks of confusion, like something didn’t fit. Like a game of Clue—everybody knew it couldn’t be Colonel Mustard with the rope, but all the evidence said otherwise.

What bugged him was the frequency, this 20-megahertz business. It was a common enough spot on the dial for amateurs. The National Institute of Standards and Technology’s radio station WWV used it too. And it never just beeped. If this new signal was indeed genuine and its creators were playing by the rules, it would be coming through at 108 megahertz, like everybody agreed upon.

Van Allen asked, “Do you think we’re getting some kind of weird transmission effect from a terrestrial station?” He wasn’t at all sure what to think, so there was a dissonance ricocheting through his brain. He had heard the news. The news was out there, but they were out here, in pretty much the middle of nowhere. And learning more wasn’t as easy as calling the neighbors. They had to take what came through, and right now there wasn’t much.

“Do you think this is really true, Larry?”

Three hours earlier a bearded, grimy, forty-two-year-old James Van Allen had been stuffing his face in the ship’s mess. They were a few days west of the Panama Canal, which coincidentally enough was also forty-two years old. Van Allen and Cahill were passengers on the uss Glacier—a naval icebreaking ship ultimately bound for the Antarctic Ocean and perhaps the last place to find two physicists from the Midwest. On paper the vessel was working Operation Deep Freeze III, aiming to pulverize ice for supply ships traveling between New Zealand and Antarctica. But that wasn’t everything that the ship did; it also carried some thirty-odd secondhand rockets stashed down in the hold, which figured into Van Allen and Cahill’s plans along the way.

Two guys with rockets? Did the captain even know? How on earth did they get aboard? For others, it might not have been so easily done. Over the preceding eleven years, James Van Allen had come to be something of an authority in the slightly obscure field of high-altitude research and had gotten to this point by playing a brilliant series of cards.

It had been a regular day, that October 4. Van Allen was familiar enough with creaky government ships to think of himself as an old hand while living on them for months at a time. He’d been in the navy in World War II through two tours—plenty long enough to demonstrate how the radio proximity fuze he coinvented could help bring down lots more enemy aircraft. That was his first card, and a professor of Van Allen’s had guided him into the position of being able to lay it down.

Antiaircraft artillery is most effective when it’s able to hit something—like an airplane you’d rather not have flying around shooting at you. And the Pacific theater’s strategy at the time was to load up the skies with shrapnel and hope to God that enemy craft ran into some of it. Unfortunately, this didn’t prove to be any kind of effective, long-term means of conducting antiaircraft operations, and it sure tended to gobble up the ammo. Timing was everything. The guns had a muzzle velocity in excess of half a mile a second. Real fast. So if the gunner’s trigger finger was off by even a second . . . well then, there went the bullet, whizzing harmlessly by that Nakajima Gekko half a mile away.

Van Allen and his brilliant cocreators tended to think outside the box, so the group took things one step further and came up with a way to have themselves a smart bullet. They built a dinky radio emitter that could withstand twenty thousand g-forces, and they capped it on top of a five-inch artillery shell. Van Allen himself was responsible for one of those back-ofa-napkin inspirational moments, cooking up an elegant way to protect the fine filaments inside the transmitter tubes from snapping after such an intense force. The final product emitted a continuous radio signal, and if the sensor sensed that it was getting close to something—like a troublesome Kawasaki Ki-61—then boom went the projectile. It was a hit, literally and figuratively, as the U.S. military scooped up the idea and sent it into production. Tens of millions were assembled and used with great success. Their effectiveness was estimated to be about five times better than plain old naked rounds. Van Allen spent months at sea training U.S. Naval crews; so by the time he walked aboard the Glacier, ships, sailing, ship ways, and even ship food were no big deal. “I was quite at home on ships, yes sir,” he said. He was even at home on this one, which featured no keel and commonly rolled twenty degrees in the lightest of winds."