Follow That Moon
I think we very likely face the embarrassing situation that, say, next spring, we have one or two [satellite tracking] cameras and the Russians have one or two satellites———————————————–
—William Pickering, October З, 1957
ickering drank the toast. He felt curiously detached from his surroundings. What thoughts did the shock loosen? Probably something like,
“ … it could have been us, what now, they said imminent, they told us—- ”
Certainly he knew better than anyone else present that his laboratory, working with von Braun’s team, might already have had a satellite aloft. And he had speculated often enough with colleagues at the Jet Propulsion Laboratory that the Russians must be ready for a launch soon. They’d feared the event, but they hadn’t truly believed it could happen.
Pickering remained deep in thought. When he looked around, his colleagues had gone. He knew where. Pickering followed to the IGY’s offices a few blocks from the Soviet embassy in downtown Washington D. C. There they sat, Dick Porter, Homer Newell, John Townsend, and Lloyd Berkner. Three years earlier, some of them had been together in a hotel room in Rome, where they had plotted late into the night how they would win backing from the General Assembly of the International Geophysical year for a satellite launch. All had an emotional investment in the unfolding events. All had campaigned to persuade their government to build a satellite. And when President Eisenhower gave the go-ahead, they’d fought amid the turbulent waters of internecine and interservice rivalry. They had not wanted the same launch vehicle and satellite, but in the end they had found common cause. Together, they faced a bitter moment.
They looked at one another and asked, Now what? Into this introspection the telephone blared. NBC had interrupted radio and television programs with the news. At the American Museum of Natural History, in New York, the phone rang every minute. Most calls were from people wanting to know how to tune into the satellite’s signal or when they could see it. For the first night at least, curiosity was uppermost, though some called to say that the stories couldn’t be true, the Russians could not have
beaten the U. S. As yet there was no panic or concern; that came the following week.
At the United States’ headquarters of the IGY, the little group remembered its priorities, decided early in their planning of Vanguard. First, place an object in orbit and prove by observation that it was there. Second, obtain an orbital track. The satellite’s path would give valuable knowledge about the earth’s gravitational field and the density of the upper atmosphere. Finally, perform experiments with instruments in the satellite. Here, too, orbital tracking and prediction would be important. An instrument isn’t much good if you don’t know where it is when it records a measurement.
All of this was for the future. That Friday night, the first priority had to be met. It wasn’t an American satellite, but something was aloft. Was it in a stable orbit, or would it plummet to Earth within hours? They let the task of learning as much as possible about the satellite’s orbit chase bitterness and disappointment away for a short time. The task was difficult, because the launch had caught them unawares.
And what was the task? They wanted to find and follow an object of indeterminate size, traveling several hundred miles above the earth at about 17,000 miles per hour. Ideally, they would have liked first to pinpoint Sputnik’s position (to acquire the satellite) then to observe parts of its orbit (to track the satellite) and to determine from those observations the parameters of that orbit.
So that they would know when and where to look to acquire the satellite, they needed to know the latitude and longitude of the Soviet launch site, and the time, altitude, and velocity at which the satellite was injected into orbit.
Imagine an analogous situation. Hijackers have taken control of an Amtrak train and no one knows where or when this happened, nor which track the hijackers have coerced the driver to follow. How does Amtrak find its train? The company could alert the public to look for its train or, if the train had a distinctive whistle, the public could listen for it. When the alert public had called in the times and places at which they spotted or heard the train, Amtrak could calculate roughly where the train would be, given an estimate of speed and a knowledge of the network of tracks. The greater the accuracy with which observers recorded the time and place of the train’s passing, the more accurately Amtrak could predict its train’s future location.
With an exact location of the launch site and information about the position and time of the satellite’s injection into orbit, the group at the IGY could have predicted Sputniks position, then tracked its radio signal and determined an orbit. But the Soviets did not release this information. In fact, they did not publicly give the latitude and longitude of the launch site for another seventeen years.
Even if they had released the information, there would have been another problem. The Russian satellite was broadcasting at 20 and 40 megahertz, frequencies that the network of American radio tracking stations set up to follow U. S. satellites—Minitrack—could not detect, even though every ham radio operator in the world could hear the satellite’s distinctive “beep beep.” The more sophisticated Minitrack stations, designed for the more sophisticated task of satellite tracking, could only detect signals of 108 megahertz. This was the frequency that the American satellite designers had adopted as the optimum, given available technology. Changing Minitrack to locate the Soviet signals involved far more than twiddling a tuning knob on a radio set.
In the days following the launch of Sputnik, Western newspaper stories speculated that the Soviets had chosen the frequency purely for propaganda purposes. Early histories quote some American scientists as saying that perhaps the Soviets chose these frequencies because they had not the skill to develop electronics to operate at higher frequencies.
Yet at the rocket and satellite conference, before the launch of Sputnik had colored everyone’s view, the Soviets’ choice of frequencies was considered in the context of science. One American delegate pointed out that the lower frequencies were better for ionospheric studies, though less good for tracking. A British delegate put forward a proposal for an ionospheric experiment with the Soviet frequencies, which found unanimous backing. During the conference, the Soviets explained a little about their network and specified the type of observations they would like other nations to make.
None of which, of course, means that propaganda did not contribute, but it shouldn’t be forgotten that in addition to the political environment, there were also Soviet scientists and engineers with scientific agendas of their own.
Whatever reason or combination of reasons the Soviets had, Minitrack could not acquire and track the satellite. It was to be a week from that night before the first of Vanguard’s radio tracking stations was successfully modified to receive the Soviet frequencies. The data, however, were not good, and the American scientists voiced their frustration to one another the following January as they prepared for their own satellite launch.
In the meantime, the phone at the IGY’s headquarters rang again. The caller had seen lights in the sky; could they be the satellite? At the IGY they didn’t know, but it seemed unlikely. For all of the men at the IGY’s headquarters, the intensity of the public’s response was a shock. Many of the calls, with their conflicting reports, were a hindrance to the task of determining where the Soviet satellite was and whether the orbit was stable.
Eventually, they realized that the best information was coming from the commercial antenna of the Radio Corporation of America near New York. Engineers there recorded a strong signal at 8:07 P. M. and again at 9:36 P. M. Pickering and his colleagues considered this information, assumed a circular orbit, and then calculated a very rough orbit from the time between signals. They concluded that it was stable. They wrote a press release, then, realizing they’d made a basic mistake in their calculations, recalculated and rewrote. They finally fell into their hotel beds at eight o’clock the next morning. Years later, after numerous glittering successes in space science, Pickering still wonders why he didn’t spot the significance of the RCA data sooner. He wonders, too, about the basic error they made, one that was too simple for this group to have made. Yet how could it have been otherwise when they had lost a dream?
Today, when military tracking equipment can locate an object the size of a teacup to within centimeters, when some antennas are set up to follow potential incoming missiles, and track across the sky at ten degrees a second, it is hard to imagine the situation the American scientists faced that night.
Had the satellite been American, elaborate plans for acquisition and tracking would have kicked in. These plans included both optical and radio techniques. Optical because, reasoned many scientists, satellites are heavenly bodies, and who better to track a heavenly body than an astronomer. Radio tracking because this was the obvious next technical development. Radio could work at any time of the day or night, unlike optical tracking, in which observations could be taken only at dawn or dusk in a cloudless sky. For both radio and optical techniques there was to be a reiterated cycle of observation and prediction, gradually refining the orbital calculation.
The scientist knew that the initial acquisition would be difficult because of the anticipated inaccuracies with which the rockets would place the satellites in orbit. The Vanguard team calculated that there would be an inaccuracy in the launch angle of perhaps plus or minus two degrees. Thus, there could be a horizontal position error in a 300-mile – high orbit of about 150 miles at any time. Added to this, the satellite would be traveling at an average of 4.5 miles per second. Further, the anticipated inaccuracy in the satellite’s eventual velocity would be equivalent to plus or minus two percent of the minimal velocity needed to stay in orbit. These errors would change a nearly circular orbit into one with some unknown degree of ellipticity.
For the sake of comparison, today’s Delta rockets can place a satellite into a low-Earth orbit with a horizontal accuracy of a little under four miles. The angle and velocity of the launch vehicle’s ascent to the point where the satellite will be injected into orbit are worked out in preflight computer simulations. Inertial guidance controls monitor the ascent, making whatever angular corrections are necessary to the path to orbit. Such was not the case in the 1950s.
In December 1956, Pickering had told the IGY’s planners that the problem they faced was whether they would ever see the satellite again once it had left the launch vehicle.
But of course, the planners worked hard to solve this problem. Minitrack would acquire the satellite, and later Minitrack observations would be complemented by optical observations.
The Vanguard design team at the Naval Research Laboratory took on the radio work under the leadership of John Mengel. Mengel’s group used a technique known as interferometry. Several pairs of antennas are needed for this technique, and the distance between each pair depends precisely on the frequency that the array is to detect. Because new positions for the antenna pairs had to be surveyed, it took a week to prepare some of Vanguard’s tracking stations to pick up Sputnik.
As soon as Mengel heard of the launch, he and his experts on orbital computation set out for the Vanguard control room in Washington D. C. He ordered modifications to the Minitrack stations so that they could receive Sputnik’s signal. These stations were located along the eastern seaboard of the United States, in the Caribbean, and down the length of South America. Within hours, additional antennas were on their way to Minitrack stations. The technicians at these sites worked round the clock, improvising in ways they would never have dreamt of the day before. In the Vanguard control room in Washington D. C., others were beginning a seventy-two-hour effort to compute the Russian satellite’s orbit from observations that were far less accurate than what they would have had, had their network been operational. The Vanguard team had planned to conduct that month the first dry run of their far-flung network’s communication links. Now Minitrack was getting what an Air Force officer called “the wettest dry run in history.”
Nearly everyone agreed that radio interferometry would be the best way to acquire the satellite. But radio techniques with satellites were unproven. The transmitters might not survive the launch or might fail. Nor were radio techniques as accurate as optical tracking. Optical tracking was the job of the Smithsonian Astrophysical Observatory (SAO) in Cambridge, Massachusetts. Under the leadership of Fred Whipple, the SAO had plans both for acquisition and tracking. Hundreds of amateur astronomers around the world were to be deployed to find the satellite (the Soviets were involved in similar efforts as part of the IGY). The amateurs’ observations would allow the computers at the Smithsonian Astrophysical Observatory to make a crude prediction of the satellite’s course, but a prediction that was precise enough for the precision camera, specially designed by James Baker, a consultant to Perkin-Elmer and Joseph Nunn, to be pointed at the area of the sky where the satellite was expected to appear. These precision cameras, roughly the same size as their operators, would photograph the satellite against the background of the stars. The satellite’s position would then be fixed by reference to the known stellar positions also recorded in the photograph.
While Berkner was toasting Sputnik at the Soviet embassy, Fred Whipple was on a plane from Washington to Boston. He had been at the conference on rockets and satellites and was on his way home. When Whipple boarded his plane late that afternoon, there was no artificial satellite in space. But satellites can’t have been far from his mind. Perhaps he thought fleetingly of the gossip among the American scientists about Soviet intentions. From this thought, it would have been an easy step to recall the previous day’s meeting of the United States IGY’s satellite committee. They’d tackled the vexed question of delays in production of the precision tracking cameras. Perkin- Elmer was fabricating the optics for these cameras, while Boiler and Chivens in Pasadena were building the camera proper. The press had reported that delays were holding up the Vanguard program. These reports were irritating to Whipple. Vanguard had been held up and would have been irrespective of the cameras. But production of the cameras was also delayed. In fact, as far as Whipple could tell, the cameras would not be ready until August 1958, only four months before the IGY was scheduled to end.
This news had not pleased Whipple’s colleagues. Dick Porter had summed up, pointing out that by August, there would be only four months of the IGY left to run. If the satellite program was discontinued at the same time as the IGY packed up, the public was going to get a very poor return on the $3.8 million it was spending on precision optical tracking. They’d discussed at length whether they should cancel the cameras but had finally decided to continue because they believed that the space program would continue. That Thursday, the day before the space age began, the IGY participants seriously considered that the satellite program might be canceled.
The big unknown that Whipple must have pondered was the Soviets. Perhaps he remembered Bill Pickering’s remarks during the meeting: “I think we very likely face the embarrassing situation that, say, early next spring, we have one or two cameras and the Russians have one or two satellites. We can live with it, but it would be embarrassing; but I think, nevertheless, it is desirable for us to have cameras as quickly as possible.”
As far as Whipple was concerned, the problem was that Perkin-Elmer had not put its best people on the job. During the meeting Porter said that he felt like going up to the plant and beating on tables, but that Whipple had discouraged such a move. Whipple’s reaction was one of incredulity. He told Porter that he would now encourage this.
Later that month, when Porter did visit Perkin-Elmer, he found that the company had underbid and was now reluctant to pay for overtime when they expected to lose money on the contract. Porter renegotiated the contract so that the company would break even. Together with the launch of Sputnik, this greatly speeded up the camera program.
By October 4, 1957, Whipple was battle-scarred. Besides the frustration of the cameras, he faced budgetary problems in the optical program. He was constantly robbing Peter to pay Paul (not that Paul always got paid on time) and he had a lot of explaining to do to both Peter and Paul. Yet he was excited. There were still things to do. It is plausible that Whipple made a mental note to check how the debugging of the computer program for orbital calculations was coming along.
Whipple knew that even if there were still a few wrinkles in the software, his staff were ready to track a satellite. On July 1, the opening day of the IGY, he had told them to consider themselves on general alert. What he did not know was that all of his preparations were at that moment being put to the test. No one enlightened him at Logan Airport, but when he got home his wife was waiting on the doorstep. Within minutes he was on his way to the Observatory.
That evening it looked as though optical acquisition was going to be more important than had been anticipated. Clearly, there could be no radio acquisition and tracking for the time being. RCA’s commercial antennas gave enough information to establish that the orbit was stable, but not enough to do any useful science or to predict the orbit with enough accuracy for aiming the precision cameras. Admittedly there were no precision cameras yet, but that was about to change.
Whipple arrived to find Kettridge Hall, which housed the tracking offices, humming with activity. At some point during the evening a fire engine arrived because a woman had reported that the building was on fire. Perhaps she thought that some nefarious activity was underway.
The news of the Russian satellite had reached the observatory at six fifteen. Everyone but J. Allen Hynek and his assistant had gone home for the weekend. Hynek was the assistant director in charge of tracking and had worked with Whipple on the tracking proposal that they had sent to the IGY satellite committee in the fall of 1955. He was discussing plans for the following week when the phone rang. A journalist wanted a comment on the Russian satellite. When the journalist had convinced Hynek that the question was serious, Hynek cleared the line and started recalling those staff who were not already on their way back to work. Those who were members of the Observatory Philharmonic Orchestra were still in the building, rehearsing for a concert. They quickly abandoned their musical instruments for scientific ones.
Hynek was particularly keen to reach Donald Campbell, Whipple’s man in charge of the amateur astronomers. Campbell, too, had been at the satellite conference but had remained in Washington because he was leaving the next day for a meeting of the International Astronautical Federation in Madrid. Part of Campbell’s job was to ensure that all the amateurs were notified when the time came. The amateurs were called Moon – watchers, after the official name for their venture, Project Moonwatch.
Hynek eventually reached Campbell in Springfield, Virginia, about fifteen miles south ofWashington, where he was visiting one of the groups of amateurs. That night, they were conducting a dry run to demonstrate their methods to Campbell. Campbell took Hynek’s call, then told the assembled group, “I am officially notifying you that a satellite has been launched.” They were thrilled to be part of the first group in the world to hear these words from Campbell. Campbell went on to make a few remarks, the coach rallying the team, but someone stopped him and set up a tape recorder to catch what he said. The next morning the Springfield Moonwatchers were at their telescopes before dawn, but they saw nothing, and would not until October 15.
Whipple had wanted armies of amateurs, but he had had to defend the idea against his colleagues’ charges that the amateurs would not be sufficiently disciplined. Ultimately, these amateurs provided invaluable information to teams operating the precision cameras. Although the Moon – watchers had not expected to begin observations until March 1958, when the first American satellite was expected to be in orbit, they were well enough organized that night to begin observing. The first confirmed Moonwatch sightings were reported by teams in Sydney and Woomera on October 8.
During the first night, Whipple, like Bill Pickering and John Mengel, tried to make sense of confusing reports, reports that were not the sort that a professional astronomer was used to. Where were the precise measurements of azimuth (distance along the horizon), elevation (height above the horizon), and time of observation? And, of course, the observatory’s program for orbital computations had still to be debugged. IBM, which was under contract to provide hardware and software support, came to their assistance the next day, dispatching experts who helped to debug the program.
Early Saturday morning, Whipple received his best observations so far from the Geophysical Institute, in College, Alaska. By nine o’clock Saturday morning, Whipple was ready for a press conference. He was dressed in a sober suit and accompanied by the props of a globe and telescopes. He gave the appearance of a man who knew what the satellite was doing. Of course, by his own standards, he had no idea.
Over that first weekend, Whipple considered the observations: the object seemed brighter than it should be. He called Richard McCrosky, a friend and colleague at the Harvard Meteor Program, and asked whether the Alaskan observation might be a meteor. McCrosky said no, and speculated that the final stage of the Russian rocket was also in orbit. Whipple contacted the Russian IGY scientists in Moscow, who confirmed that the final rocket stage was indeed in space, trailing the satellite by about six hundred miles. The rocket was painted brightly and had the luminosity of a sixth-magnitude star—bright enough to be visible through binoculars. The official nomenclature for the rocket and Sputnik I gave them the names “1957 alpha one” and “1957 alpha two.” The rocket, being the brighter object, was “alpha one.”
Eventually, Whipple concluded that Sputnik I itself was probably painted black. Although he was wrong, it is doubtful that any of the amateurs ever spotted the satellite; their observations, about two thousand of them by the end of 1957, were probably all of the rocket. Certainly, the Baker-Nunn precision cameras never picked up Sputnik I, though special meteor cameras that McCrosky lent to Whipple until the Baker-Nunns were ready did acquire the satellite on Thanksgiving day.
The observatory published its first information of scientific quality October 14; the document was called The preliminary orbit information for satellites alpha one and alpha two. Later the Observatory issued regular predictions of the time and longitude at which alpha one would cross the fortieth parallel, heading north. More detailed information was available to Moonwatch teams so that they would know when to be at their telescopes to make observations.
One of the Springfield Moonwatchers was a teenager named Roger Harvey. On the evening of October 4, he was driving his father’s 1953 Ford back from Maryland, where he had picked up a mirror for a ten-inch telescope that he was building for a friend. He was listening to the radio. When he heard about the Russian satellite, he was exhilarated. Someone had really done it—sent a satellite into space. Now, he thought, we’ll see some action.
When President Eisenhower had announced that the United States would launch a satellite, Harvey and his fellow amateur astronomers had wondered what it would mean to them. They’d decided that they would establish an observing station on land owned by the president of their local astronomy club, Bob Dellar. Nowadays Springfield is part of the seemingly endless conurbation of Washington D. C. and northern Virginia. Then it was rural and had a beautifully dark sky for observing.
The group had modeled the layout of their observing station on one that they’d seen in Bethesda, Maryland. One weekend, they’d arranged the observing positions in a single straight line, extending on either side of a fourteen-foot high, T-shaped structure. Harvey thought that the T, which was made out of plumber’s pipe, looked like half of a wash-line support for the Jolly Green Giant. The six-foot crossbar was aligned with the meridian, with the north-south line immediately overhead. A light shone precisely where the T crossed the upright. Like most of the Moonwatchers, they’d made their own telescopes, each of which had a 12-in. field of view. The fields of view overlapped one another by fifty per cent, so that it wouldn’t matter if one observer fell asleep or missed something.
If one of the team was lucky enough to see the satellite, he would hit a buzzer and call out the number of his observing station at the moment when the satellite crossed the meridian pole. Bob Dellar would have his double-headed recorder switched on. One channel would be recording the national time signal from a shortwave radio, while the other channel would record their buzzers and numbers. The T would determine the meridian; they knew their latitude and longitude; the double-headed tape would have recorded the time of the observation accurately; and they could work out the satellite’s elevation to within half a degree by measuring the distance between the central light and the point where the satellite crossed the meridian. Thus they would have elevation for a specific time and place. When they made an observation, Dellar would call the operator, speak the single word, Cambridge, and be put through to the observatory. After that it would be up to the professionals.
There had been dry runs. The Air Force had flown a plane overhead at roughly the right altitude and speed to simulate the satellite’s passage. The aircraft had trailed a stiff line with a light on the end. It was important that the Moonwatchers not see the light too soon, so the Air Force had taken the rubber cup from a bathroom plunger, threaded a loop through it to attach to the line to the aircraft, and put a small light and battery in the plunger. The practices had worked well. The plane had flown over with its navigation lights out, which, while strictly illegal, was necessary.
When Harvey got home, he was anxious to hear from Dellar. The arrangement was that the observatory would call team leaders with predicted times that the satellite would cross the equator. Dellar would work out at what time the Moonwatchers needed to be at their telescopes. Of course, it would be a little different now, because it wasn’t their satellite and the observatory might not have good predictions. All the same, Harvey was ready when Dellar called the next morning. For the next few weeks, Harvey lived at a high pitch of excitement. He felt himself part of history. Even the police seemed to be on his side. When he was stopped for speeding, he told the officer he was a Moonwatcher, and he was sent on his way without a ticket. The Springfield Moonwatchers felt great camaraderie, and no one pulled rank. On cloudy nights, they would swear at the sky on the principle that if they generated enough heat, they would dissipate the clouds.
On the other side of the continent, in China Lake, California, the skies were much clearer and very, very dark—ideal for observing. Florence Hazeltine, a teenage girl, who was later to become one of the first doctors in the United States to use in vitro fertilization techniques, would bundle up against the cold and ride out on her bike to answer the same calls that drew Harvey to Dellar’s house. Like Harvey, she was buoyed by her sense of being part of history.
In Philadelphia, sixteen-year-old Henry Fliegel reported to the roof of the Franklin Institute. He wrote in his observing notes:
“On October 15, I saw with all the other members of the station a starlike object move across the sky from the vicinity of the pole star across Ursa Major to Western Leo. It attained a magnitude of at least zero when in Ursa Major, but then rapidly faded and finally became too dim to see when still considerably above the horizon, disappearing very near the star Omicron Leonis.”
The Philadelphia Moonwatchers had seen Sputnik’s rocket. When the news hit the papers, sightseers and reporters turned up and sat at the telescopes, sometimes taking the telescopes out of their sockets as soon as anything appeared.
Elsewhere, the initial confusion was beginning to sort itself out. By the fifteenth, the first precision camera was nearly ready to begin operation. Moonwatchers deluged Cambridge with news of sightings. These were of the rocket, but it didn’t matter. It was a body in orbit and the teams were honing their skills. Engineers were ironing out the inevitable wrinkles of the Minitrack system.
The space age was underway.