SP-466 The Star Splitters
 

6

THE STAR SPLITTERS

 

[37] The instruments that flew aboard the HEAOs have allowed us to split, or analyze, the radiation from stars and galaxies in a special way. By using a carefully chosen complement of detectors to study the various aspects of high energy cosmic radiation, they have given us a glimpse of the hot spots in the universe. They allow us to probe regions of space where particles have been raised to very high energies by strong magnetic fields, violent explosions, or intense gravity.

The HEAO I mission carried an array of independent but complementary experiments designed to survey and map X-ray sources throughout the celestial sphere. The instruments had the capability of locating X-ray sources and studying their variation in time and the distribution of their radiation with energy over a broad range of X-ray energies. HEAO 3 carried three instruments designed to survey the sky for cosmic sources of gamma radiation and to take samples of cosmic rays, the high energy particles that reach Earth from outside the solar system. HEAO 2 was the most complex of the missions. It carried a large X-ray telescope that produced the first detailed X-ray images of objects outside the solar system. These images were analyzed by interchangeable instruments at the focal plane of the telescope.

Building an instrument for astronomical observations is never easy, because astronomers push instrument technology to the limit as they try to wring yet another drop of information from some distant source on the dim boundary of observability. As Herb Friedman put it, "There is no better way to check an instrument than through astronomy. Building an instrument for space astronomy is triply difficult. The scientists and engineers working on the HEAO missions not only had to cope with technology pushed to the limit, or in some cases invent new technology. They had to work with the knowledge that once the spacecraft was launched, it would be gone. There would be no possibility of recalling the spacecraft to work out the bugs. It had to be done right the first time. On top of this, they had to put the missions together on a tight budget, and to stay on a tight schedule, because, on a project such as HEAO, time was money'."

All these factors made HEAO, in the words of Tom Parnell, project scientist for HEAO 3, "an ulcer generating business." Adding to the tension was the ever present possibility of cancellation. "I always felt like we were on the brink of cancellation," said Claude Canizares of MIT, a member of the consortium of scientists that worked on HEAO 2, "either in terms of a [38] whole project or our individual experiment." According to Al Opp, NASA program scientist for HEAO, Canizares' feelings were not realistic. "HEAO was always a problem because it was always a little underfunded.... HEAO 2, with its exceedingly sophisticated, exceedingly complicated optical system, was the most difficult. It was a larger and more difficult mission than everyone had estimated. It was very difficult to keep the cost down and keep the mission intact at the same time."

NASA's understandable concern to keep close to budget caused worries among the scientists that NASA was being penny wise and dollar foolish. "There's a cost effectiveness threshold," Dan Schwartz of the Center for Astrophysics, who became one of the principal investigators on HEAO 1, observed. "If you don't do it with a certain quality, you get nothing. I felt that NASA was always pushing that threshold." Another scientist termed this the bridge builder's philosophy, according to which "They seemed to have the point of view that whereas it would be a disaster to build a bridge an inch too short, it would be silly to make it a foot too long. They very much stuck to the minimum requirements, when a little extra might have yielded a substantial gain in quality." Other scientists seemed to worry that NASA might misjudge how long the "bridge" would have to be and were thereby courting disaster. On the other hand, many took the point of view of Walter Lewin, who felt that things would never quite get that bad if the principal investigators were sufficiently vocal. "The responsibility for the integrity of the experiment is in the final analysis on the Pl's shoulders. If he...

 


HEAO 1 experiment configuration.

HEAO 1 experiment configuration.


[39]

HEAO A-1 Experiment, the Large Area X-ray Survey Experiment. The A-1 experiment consisted of seven modules of thin window X-ray proportional counters, central electronics, two stellar aspect assemblies, and a gas system. The major purpose of the experiment was to map the celestial sphere for X-ray sources and to determine the spectrum, intensity, and time variations of the radiation from these sources. The Principal Investigator for A-l was Herbert Friedman of the Naval Research Laboratory (NRL). Hardware was produced by NRL with assistance from New Mexico State University, Las Cruces.

.

 

HEAO A-1 Experiment, the Large Area X-ray Survey Experiment. The A-1 experiment consisted of seven modules of thin window X-ray proportional counters, central electronics, two stellar aspect assemblies, and a gas system. The major purpose of the experiment was to map the celestial sphere for X-ray sources and to determine the spectrum, intensity, and time variations of the radiation from these sources. The Principal Investigator for A-l was Herbert Friedman of the Naval Research Laboratory (NRL). Hardware was produced by NRL with assistance from New Mexico State University, Las Cruces.

.

HEAO A-1 Experiment, the Large Area X-ray Survey Experiment. The A-1 experiment consisted of seven modules of thin window X-ray proportional counters, central electronics, two stellar aspect assemblies, and a gas system. The major purpose of the experiment was to map the celestial sphere for X-ray sources and to determine the spectrum, intensity, and time variations of the radiation from these sources. The Principal Investigator for A-l was Herbert Friedman of the Naval Research Laboratory (NRL). Hardware was produced by NRL with assistance from New Mexico State University, Las Cruces.



[40 - 41]

The Cosmic X-ray Experiment, HEAO A -2.

The Cosmic X-ray Experiment, HEAO A -2.

 

.

The Cosmic X-ray Experiment, HEAO A -2. The A-2 experiment consisted of six collimated detectors of thin window X-ray proportional counters, electronics, and a gas system. The major purpose of the experiment was to measure the emission and absorption of cosmic X-rays in the energy range of 0.2 to 60 kiloelectron volts. Principal Investigators were Elihu Boldt of Goddard Space Flight Center and Gordon Garmire of Pennsylvania State University. Hardware was produced by Goddard. Others assisting in the program were the Bendix Corporation, the University of California, and the California Institute of Technology.

 

....screams loudly enough, then NASA will do what is needed." Jim Matteson of the University of California at San Diego, who worked on HEAO 1, had the same feeling. "Dick Halpern once told us to do it with as little money as possible, but not to sell the farm. I never quite knew what he meant by that, but I took it to mean that if things got desperate, the extra money would be found."

One example of this was the effort to upgrade HEAO I so that it would have pointing capability. Hale Bradt realized that HEAO I could do a much better job if only it had the ability to point at specific sources rather than just scan over them. But it would take more money. Fortunately, Bradt, with good foresight, realized the importance of a pointing capability early in the program and was able to convince the NASA officials, especially Dick Halpern, of its value. By modifying the budget in other areas, Halpern created a reserve fund to cover the extra cost of installing the necessary gas jets to give HEAO I a pointing capability that greatly enhanced the value of the mission.

 


[42]

The Scanning Modulation Collimator, HEAO A-3. The A-3 experiment consisted of two scanning modulation collimators with proportional counters, aspect sensors, and electronics. The major purpose of this experiment was to determine accurately the position of selected cosmic X-ray sources and to investigate their size and structure. Principal Investigators were Herbert Gursky and Daniel Schwartz of the Smithsonian Astrophysical Observatory and Hale Brad t of MI T. Hard ware was provided by American Science and Engineering, Inc.

.

The Scanning Modulation Collimator, HEAO A-3. The A-3 experiment consisted of two scanning modulation collimators with proportional counters, aspect sensors, and electronics. The major purpose of this experiment was to determine accurately the position of selected cosmic X-ray sources and to investigate their size and structure. Principal Investigators were Herbert Gursky and Daniel Schwartz of the Smithsonian Astrophysical Observatory and Hale Brad t of MI T. Hard ware was provided by American Science and Engineering, Inc.

.

The Scanning Modulation Collimator, HEAO A-3. The A-3 experiment consisted of two scanning modulation collimators with proportional counters, aspect sensors, and electronics. The major purpose of this experiment was to determine accurately the position of selected cosmic X-ray sources and to investigate their size and structure. Principal Investigators were Herbert Gursky and Daniel Schwartz of the Smithsonian Astrophysical Observatory and Hale Brad t of MI T. Hard ware was provided by American Science and Engineering, Inc.


[43]

Hard X-ray and Low Energy Gamma Ray Experiment, HEAO A-4. The A-4 experiment consisted of a modular array of phoswich scintillator detectors, particle monitors, a digital processor containing power conditioning, and data handling electronics. The purpose of the experiment was to determine the position, spectrum, time variations, intensity, and other properties of selected X- and gamma ray sources in the energy range of 10 to 10000 kiloelectron volts. Principal Investigators were Laurence Peterson of the University of California at San Diego (UCSD) and Walter Lewin of MIT. Experiment hardware was provided by UCSD and Time Zero Laboratories of Ball Brothers Research Corporation.

.

Hard X-ray and Low Energy Gamma Ray Experiment, HEAO A-4. The A-4 experiment consisted of a modular array of phoswich scintillator detectors, particle monitors, a digital processor containing power conditioning, and data handling electronics. The purpose of the experiment was to determine the position, spectrum, time variations, intensity, and other properties of selected X- and gamma ray sources in the energy range of 10 to 10000 kiloelectron volts. Principal Investigators were Laurence Peterson of the University of California at San Diego (UCSD) and Walter Lewin of MIT. Experiment hardware was provided by UCSD and Time Zero Laboratories of Ball Brothers Research Corporation.

.

Hard X-ray and Low Energy Gamma Ray Experiment, HEAO A-4. The A-4 experiment consisted of a modular array of phoswich scintillator detectors, particle monitors, a digital processor containing power conditioning, and data handling electronics. The purpose of the experiment was to determine the position, spectrum, time variations, intensity, and other properties of selected X- and gamma ray sources in the energy range of 10 to 10000 kiloelectron volts. Principal Investigators were Laurence Peterson of the University of California at San Diego (UCSD) and Walter Lewin of MIT. Experiment hardware was provided by UCSD and Time Zero Laboratories of Ball Brothers Research Corporation.

 

[44] Everyone in the program had the same goal: to put three observatories in orbit that could fulfill the scientific objectives as stated in the proposal and to do it within cost and schedule. However, given the austere budget and the ambitious scientific objectives, it is fairly certain that this goal would not have been achieved if each group had not become strong advocates of its own particular viewpoint and responsibility. This understandably led to conflicts between one group of scientists and another, between scientists and subcontractors, between NASA and subcontractors, and between scientists and NASA.

The focal point of much of this conflict was Marshall Space Flight Center. Marshall was the NASA center with responsibility for HEAO. The program manager at Marshall was Fred Speer, a man with very definite ideas as to how the project should be managed. Many scientists, used to the informal style of small projects involving the flight of a balloon or a sounding rocket, were unprepared for Speer's highly formal style, developed during his experience with the Apollo manned space program. Halpern, always short of money, directed Speer to build the large, complex HEAO instruments just once and then to solve whatever problems that might develop, rather than to build two or three versions of them. Basically, the idea was that the engineering model, the prototype, and the flight unit would all be rolled into one. This concept was called "protoflight" (prototype + flight). It resulted in a great cost savings and a great increase in the pressure to get everything done right the first time and to stay on a strict schedule.

Most of the scientists, though not thrilled with the idea of having to build an entirely new type of instrument so that it worked correctly the first time it was tried, agreed that the protoflight approach was probably a necessity of life, given the limited budget. However, they did not view the documentation required by Marshall in the same light. "I hated the interminable paperwork," one scientist complained. Still another scientist said

"If we would've done everything that they asked us, the thing would still not be in orbit." Still others sought solace in humor. Bob Farnsworth, an engineer at the University of California at San Diego, used to cheer himself up when he was buried in documentation requirements by remembering the advice of his colleague Mike Pelling. "Well, when it's all over with," Pelling said, "just think how much better off they'll be." Tom Parnell, who had been through it all before in his years at Marshall, admitted, "It is a real shock to people who haven't been through it. We must prethink everything in nagging detail, everything that could go wrong and prepare for it. Also we have to worry about cost. The paperwork raises the cost, but it guarantees that, when we launch, everything we can do to ensure success is done. "

Another objection heard more than once was that Marshall was too arbitrary in both a technical and monetary sense, so that minor changes in the...

 


[45]

Schematic of a thin window gas proportional counter.

Schematic of a thin window gas proportional counter. The beryllium window is cemented between a supporting "sandwich, " which in turn is hermetically sealed to the cathode to preserve the gas integrity. An X-ray photon entering the counter produces a cloud of electron-ion pairs in the gas. The electrons drift to the anode, producing an electric signal.

 

...original plans were for the most part not allowed, even though they might have resulted in an overall cost savings, because they would have made the analysis of the data easier. This frustration led in at least one case to sub rosa techniques. Elihu Boldt wanted to add a provision for checking for bit errors in the data system of his instrument. (A bit error is an error that occurs in the transmission of data from one location to another, in this case from the spacecraft to the ground.) Engineers at Marshall assured him that the telemetry system was so good that the number of bit errors would be so low that there was no need to check for them. "But bit errors tend to occur in bursts and look remarkably like the data we get from some of the more interesting X-ray sources. We had to have a way to tell whether we were seeing a bit error or an X-ray burst, but they wouldn't allow it. So we put it in under another name. We called it a 'block encoder,' end they accepted it."

On the other hand, the relations between the scientists were not always a bed of roses either. "I found the negotiations within the consortium of scientists much more difficult than with Marshall," one scientist remarked. "They were draining, not so much because of the personalities involved, but because the problems were real, and they were all very dedicated to their own ideas and very capable of defending their own turf." On balance, ....


[46]

Gordon Garmire

Gordon Garmire

.

Stuart Bowyer

Stuart Bowyer

.

Claude Canizares (Photo by Karen Tucker)

Claude Canizares (Photo by Karen Tucker)

Robert Novick

Robert Novick

 


[47]

Left to right. George Clark, Roger Doxsey, and Hale Bradt. (Photo by Karen Tucker)

Left to right. George Clark, Roger Doxsey, and Hale Bradt. (Photo by Karen Tucker)

 

Dan Schwartz and Leon Van Speybroeck. (Photo by Karen Tucker)

Dan Schwartz and Leon Van Speybroeck. (Photo by Karen Tucker)

 

...though, most scientists were pleasantly surprised at how well they could work with colleagues who had often been on opposite sides of spirited rivalries, and many cited the interaction with other scientists and engineers as one of the high points of the project. They were not without kind words for the people at Marshall. Leon Van Speybroeck and others singled out Jim Power, a Marshall manager/engineer who was killed in an airplane crash while on HEAO business. "Jim was a very positive influence on the program. He genuinely tried to support the science and to use the resources at hand wisely." Hans Fichtner was praised by Hale Bradt and others as a "very enlightened engineer." And everyone seemed to agree that Carroll Dailey and Joseph B. Jones had a lot to do with the success of HEAO.

[48] "They had fantastic sympathy for the experimenters," recalled Jim Matteson. Fred Speer, when looking back over the experience, said, "I hated to lose all the good people associated with the team. It was a sad moment to see them leave." He also praised the "overall team spirit that motivated the entire HEAO team" as an important factor in the success of the program. "This was accomplished by complete and open communications."

How did the scientists feel about Fred Speer once it was all over? "Fred Speer was a very excellent manager," said Frank McDonald, the HEAO I project scientist. Others were more reserved, but admitted that he earned their respect. "Fred Speer took his part of the world and made it work differently," said Ray Jorgensen, technical manager for the HEAO 3 gamma ray spectrometer at the Jet Propulsion Laboratory in Pasadena, California. "Although the management was way too much in the Apollo style," said Walter Lewin, "Speer deserves quite a bit of credit for some major decisions, particularly with respect to the gyros."

The gyros, or gyroscopes, were responsible for the only schedule slippage on HEAO 1. Gyroscopes are used in spacecraft to sense the rotation rates of the spacecraft. Through electronic controls, they provide data on the motion of the spacecraft. These data may be processed by an on-board computer to derive vehicle control corrections or be telemetered to the...

 


Laurence Peterson

 

.

Jim Matteson (center) and colleagues check out the HEAO A-4 experiment.

.

Laurence Peterson

Jim Matteson (center) and colleagues check out the HEAO A-4 experiment.


[49]

August 13, 1977. The launch of HEAO 1.

August 13, 1977. The launch of HEAO 1.


[50]

Atlas-Centaur ascent profile.

Atlas-Centaur ascent profile.

 

Event

Basis

Approx. time from liftoff (sec.)

.

Liftoff

2-in. Motion

0

Roll Program

Liftoff + 2 sec.

2-15

BECO

5.49g

140

.

Booster package jettison

BECO + 3.1 sec.

143

Jettison insulation panels

BECO + 45 sec.

185

SECO

Prop. depletion

251

.

Separation

SECO + 1.9 sec.

253

MES 1

SECO + 11.5 sec.

263

Jettison nose fairing

MES 1 + 12 sec.

275

MECO 1

Parking orbit (guid.)

707

.

Separation

MECO + 665 sec.

1372

.

Start retromaneuver

MECO 1 + 675 sec.

1382

Propellant blowdown start

MECO 1 + 3750 sec.

4397


 

[51] ....ground to provide detailed information about the motion of the spacecraft. Only a few months before the launch of HEAO I, the gyros began to act up. They would short out in vacuum, or they would give erroneous readings. Over a period of six weeks, more than thirty such glitches occurred. There was no alternative but to postpone the launch until the gyro problem could be solved. Weeks and then months went by, and still the problem persisted. The scientists, knowing Speer's dedication to keeping on schedule, began to worry that he would launch the spacecraft anyway, knowing that it would last only six months, the minimum time for the mission to be considered a success. "Our concern was very misplaced, " said Jim Matteson. "We learned that the problem was handled very effectively." Fred Wotjalik and other engineers worked overtime, making extra tests to reassure themselves that the gyros would work once the spacecraft was launched. Still, no one knew for sure what had caused the original problems, so they did not know for sure whether they would recur in orbit. A decision had to be made as to whether to keep fixing the gyros or to fly them. Halpern and Speer decided to fly them. "The gyro testing was agonizing," Herb Friedman remembered. "When we finally went, Dick Halpern told me it was OK. But I thought it was still a gamble."

The launch is always the most tense time of any space project, because if anything goes wrong then, it's all over. There could be no "soft failure" because there was no backup spacecraft. Everyone tries to stay calm, but no one succeeds. Even a veteran such as Fred Speer finds the countdown

 


Schematic of HEAO 2.

Schematic of HEAO 2.


[52]

The High Resolution Imager, HEAO B-2. Designed to use the imaging capability of the X-ray telescope, the High Resolution Imager used advanced solid-state techniques to record the images with a resolution of I to 2 arc seconds, the limit of the resolution capability of the telescope itself. The Principal Investigator was Riccardo Giacconi. Hardware was developed by American Science and Engineering.

.

The High Resolution Imager, HEAO B-2. Designed to use the imaging capability of the X-ray telescope, the High Resolution Imager used advanced solid-state techniques to record the images with a resolution of I to 2 arc seconds, the limit of the resolution capability of the telescope itself. The Principal Investigator was Riccardo Giacconi. Hardware was developed by American Science and Engineering.

.

The High Resolution Imager, HEAO B-2. Designed to use the imaging capability of the X-ray telescope, the High Resolution Imager used advanced solid-state techniques to record the images with a resolution of I to 2 arc seconds, the limit of the resolution capability of the telescope itself. The Principal Investigator was Riccardo Giacconi. Hardware was developed by American Science and Engineering.

.

[53]

Operation of the High Resolution Imager. X-rays enter the microchannel plates shown at the top of the figure. The X-rays produce a cascade of photoelectrons that emerge from a few tubes at the surface. The electron charge cloud spreads over the criss-crossed grid of very fine wires. This grid of wires produces the electric signals that are decoded to give the position of the incoming X-ray.

.

Operation of the High Resolution Imager. X-rays enter the microchannel plates shown at the top of the figure. The X-rays produce a cascade of photoelectrons that emerge from a few tubes at the surface. The electron charge cloud spreads over the criss-crossed grid of very fine wires. This grid of wires produces the electric signals that are decoded to give the position of the incoming X-ray.

 


[54]

Steve Murray demonstrates how the prototype of the High Resolution Imager was put together. (Photo by Karen Tucker)

.

Patrick Henry

.

Steve Murray demonstrates how the prototype of the High Resolution Imager was put together. (Photo by Karen Tucker)

Patrick Henry

 

...."nervewracking." To Bob Farnsworth, it was "mindboggling. Seven or eight years of your life are sitting on top of a rocket." Hale Bradt was "impressed by how thin and fragile it looked." To Harvey Tananbaum, the scientific program manager of HEAO 2 from Harvard-Smithsonian, the rocket was "just beautiful," though he, too, found that it was "a frightening prospect to have millions of dollars and years of your life riding on the line." Jim Matteson's experience was typical. "I remember trying to rationalize away a disaster on the way down, saying to myself, 'well, if it blows up or doesn't go into orbit, I can live with ft.' thirty minutes before launch all this collapsed, and I realized that anything short of success would be an emotional disaster. "

 


[55]

The Imaging Proportional Counter, HEAO B-4.

.

The Imaging Proportional Counter, HEAO B-4.

The Imaging Proportional Counter, HEAO B-4. The Imaging Proportional Counter used the same basic techniques as most of the X-ray detectors on HEAO 1, but the counter was electronically subdivided into very small regions so that each registered a small part of the X-ray image. The result was an image with a resolution of about 1 arc minute. What the Imaging Proportional Counter lacked in imaging resolution, it made up in greaser geld of view than the High Resolution Imager. The Principal Scientists were Herbert Gursky and Paul Gorenstein of Smithsonian Astrophysical Observatory. Hardware was developed by American Science and Engineering.

 

The night of the launch an electrical storm moved into the Cape Canaveral area, and the launch, scheduled shortly before midnight on August 11, 1977, was put off for an hour. The spacecraft computer went down, and a decision was made to load the program through Goddard, a very tricky maneuver. In the meantime, another complication had arisen. Several fishing boats were in the area where the rocket would be jettisoned after launch Attempts to reach them by radio and get them to clear the area had failed. Helicopters were dispatched to drop messages on their decks. Because of the bad weather, the crews were below deck and did not respond. The launch was postponed another hour as the Launch Director waited for both the weather and the fishing boats to clear. Finally, Skip [56] Mackey reached the fishing boats by a CB radio, and they turned south. The weather cooperated, too, and shortly after 2 a.m. HEAO I was launched.

For a little over two minutes the booster engines lifted the rocket away from Earth and into space. At 253 seconds after liftoff, separation of the booster engine from the main engine occurred. Ten seconds later the main engine started to burn. It burned for 434 seconds, taking the spacecraft over 200 miles above the surface of Earth. Almost 23 minutes after launch, the....

 


The Focal Plane Crystal Spectrometer, HEAO B-3.

 

The Focal Plane Crystal Spectrometer, HEAO B-3.

The Focal Plane Crystal Spectrometer, HEAO B-3. The Focal Plane Crystal Spectrometer made use of the X-ray diffraction properties of certain crystals to study in detail the X-ray spectra produced by celestial targets. The detector for the diffracted rays was a small proportional counter. This instrument could detect individual X-ray emission lines to h help unravel questions about the chemical composition and other properties of cosmic X-ray sources. The Principal Scientist was George Clark of MIT. Hardware was developed by MIT.


[57]

The Solid State Spectrometer, HEAO B-5. The Solid State Spectrometer had to be cryogenically cooled with solid methane and ammonia for its silicon-germanium crystal to function properly. Its advantage was that it could observe the entire spectrum at once, measuring the energy of each photon hitting the crystal, whereas the Focal Plane Crystal Spectrometer could examine only a small band of energies at any one setting of the crystal tunes. The two spectrometers complemented each other in sensitivity and energy resolution.

The Principal Scientist was Elihu Boldt of Goddard Space Flight Center.

.

The Solid State Spectrometer, HEAO B-5. The Solid State Spectrometer had to be cryogenically cooled with solid methane and ammonia for its silicon-germanium crystal to function properly. Its advantage was that it could observe the entire spectrum at once, measuring the energy of each photon hitting the crystal, whereas the Focal Plane Crystal Spectrometer could examine only a small band of energies at any one setting of the crystal tunes. The two spectrometers complemented each other in sensitivity and energy resolution.

The Solid State Spectrometer, HEAO B-5. The Solid State Spectrometer had to be cryogenically cooled with solid methane and ammonia for its silicon-germanium crystal to function properly. Its advantage was that it could observe the entire spectrum at once, measuring the energy of each photon hitting the crystal, whereas the Focal Plane Crystal Spectrometer could examine only a small band of energies at any one setting of the crystal tunes. The two spectrometers complemented each other in sensitivity and energy resolution. The Principal Scientist was Elihu Boldt of Goddard Space Flight Center. Hardware was developed by Goddard under an intercenter agreement.


[
58]

The Monitor Proportional Counter, HEAO B-1. The Monitor Proportional Counter was mounted near one end of the observatory and operated independently of the telescope. It observed the same region of sky as the telescope but over a much wider energy range. It provided a means of correlating observations made by all the focal plane instruments. The Principal Investigator was Riccardo Giacconi. Hardware was developed by American Science and Engineering.

The Monitor Proportional Counter, HEAO B-1. The Monitor Proportional Counter was mounted near one end of the observatory and operated independently of the telescope. It observed the same region of sky as the telescope but over a much wider energy range. It provided a means of correlating observations made by all the focal plane instruments. The Principal Investigator was Riccardo Giacconi. Hardware was developed by American Science and Engineering.

 


Paul Gorenstein

Harvey Tananbaum

.

Paul Gorenstein

{Photo by Karen Tucker)

Harvey Tananbaum

(Photo by Karen Tucker)


 


[
59]

Schematic of the Crazing Incidence X-ray Telescope.

Schematic of the Crazing Incidence X-ray Telescope. X-rays entering the telescope strike the slightly curved mirrors at a grazing angle and are concentrated in the focal plane. The four concentric mirrors concentrated the flux of X-rays so that objects 1000 times fainter than ever detected before could be examined in detail. (Smithsonian Institution Photo No. 80-20240)

 

.....main engine separated from the spacecraft. HEAO 1 was in orbit. Dick Halpern and Fred Speer were the last to leave the Control Center. Heading toward town, they both felt so drained they decided to pass up the postlaunch celebration party. It had been a long road together. A few days later, the instruments were activated and began to return data. More than a decade after that first meeting at Woods Hole, the first HEAO was a reality.

Meanwhile, the HEAO 2 team was pushing to meet their launch deadline of November 1978, only 15 months away. HEAO 2 was quantitatively different from the other missions and from anything that had been tried before. In the understated words of Paul Gorenstein of Harvard Smithsonian, "it was a somewhat audacious step, because no prototype for the instruments existed. But we were confident we could do it." The goal of the HEAO 2 team was nothing less than to put the young science of X-ray astronomy on a par with optical and radio astronomy. To do this, they planned to make an X-ray observatory that would detect sources a thousand times fainter than any previously observed. They hoped to accomplish this by flying a complex array of mirrors that would focus X-rays onto one of....

 


[
60]

The HEAO 2 X-ray mirror completely assembled for ground testing. (Photo courtesy Perkin-Elmer Corp.)

The HEAO 2 X-ray mirror completely assembled for ground testing. (Photo courtesy Perkin-Elmer Corp.)

 

[61] ....several sensitive X-ray detectors. Several detectors would be needed because it was not possible to build a single detector that could make fine images and detailed spectral measurements, see a large field of view, and detect very weak sources. The absence of a single detector with all desired properties meant that the scientists involved would have to work together closely to develop a complement of detectors capable of achieving the objectives of the observatory. A unified scientific approach would be necessary to deal with the many problems that would arise and the compromises and tradeoffs that would be necessary. Accordingly, from the very beginning, in the proposal stage, a consortium of experimenters was organized. The consortium included scientists from AS&E, Columbia University, Goddard Space Flight Center, MIT, and the Smithsonian Astrophysical Observatory, with Riccardo Giacconi of the Smithsonian as the Principal Investigator and Scientific Director of the observatory. The consortium scientists agreed that, in addition to obtaining data from the instruments for which their individual institutions had responsibility, all scientists would share in the data from all instruments.

The four focal plane detectors chosen were the High Resolution Imager, the Imaging Proportional Counter, the Solid State Spectrometer, and the Focal Plane Crystal Spectrometer. The High Resolution Imager offered the highest spatial resolution. However, it had no energy resolution, and its field of view was small. The Imaging Proportional Counter could detect weaker sources than the High Resolution Imager, had a wider field of view, could make "broad brush" images of sources, and had a modest degree of....

 


The X-ray telescope calibration facility at Marshall Space Flight Center.

The X-ray telescope calibration facility at Marshall Space Flight Center.


[
62]

HEAO 2 is installed in calibration facility vacuum chamber.

HEAO 2 is installed in calibration facility vacuum chamber.

 

.....energy resolution. This versatile instrument was the workhorse of the observatory and was the most used instrument. It was designed and developed by Paul Gorenstein and F.R. Harnden of the Smithsonian. The Solid State Spectrometer developed by Elihu Boldt, Stephen Holt, and Robert Becker could observe the entire spectrum at once, measuring the energy of each photon that hit the silicon germanium crystal at the heart of the detector. The Focal Plane Crystal Spectrometer developed by George Clark, Claude Canizares, and Tom Markert of MIT was used to study the details of the....

 


[
63]

Fred Seward and son Robert (Photo by Susan Seward)

November 13, 1978. The launch of HEAO

.

Fred Seward and son Robert (Photo by Susan Seward)

.

.

Ethan Schreier

.

Ethan Schreier

November 13, 1978. The launch of HEAO 2.

 

[64] ....spectra in a narrow energy band for strong X-ray sources. Two other auxiliary instruments augmented the capabilities of the observatory. They were the Objective Grating Spectrometer, which for strong sources could be used with the High Resolution Imager to provide spectral information, and the Monitor Proportional Counter, which was situated outside the focal plane with a viewing direction parallel to the telescope axis and served as a continuous monitor on the sources viewed by the telescope. The Columbia....

 


First light of HEAO 2, now nicknamed the Einstein Observatory: the black hole candidate, Cygnus X-1.

First light of HEAO 2, now nicknamed the Einstein Observatory: the black hole candidate, Cygnus X-1.


Einstein <<first light>> party at the Harvard-Smithsonian Center for Astrophysics. Left to right. Leon Van Speybroeck, Kenton Evans, Martin Elvis, Pepi Fabbiano, Arnold Epstein, Graziella Branduardi-Raymont, Mirella Giacconi, and Riccardo Giacconi. (Photo by Fred Seward)

Einstein "first light " party at the Harvard-Smithsonian Center for Astrophysics. Left to right. Leon Van Speybroeck, Kenton Evans, Martin Elvis, Pepi Fabbiano, Arnold Epstein, Graziella Branduardi-Raymont, Mirella Giacconi, and Riccardo Giacconi. (Photo by Fred Seward)

 

[65] ....University group consisting of Robert Novick, Knox Long, William Ku, and David Helfand participated in all scientific aspects of the mission. Ethan Schreier of the Smithsonian directed the mission operation planning and implementation. Ted Kirchner of AS&E was the program manager for the experiment during the early design and development phase. When the experiment entered the manufacturing phase, Bruce Dias became program manager and was responsible for directing the manufacture, assembly, integration, and testing of the experiment.

The Solid State Spectrometer had to be cooled with solid methane and ammonia to a temperature of about 100 K ( - 280° F) in order to work properly. This requirement created difficult design problems. Steve Holt recalled some of those problems. "There was a chance that the vent lines could clog with ice and explode. We had to prove that it would rupture internally first. Riccardo felt that he was flying a bomb on the observatory. Every place we took it, to American Science and Engineering, to TRW and then to the Cape, it had to be monitored 24 hours a day." No serious mishaps occurred, but even so, there was a constant worry that something would go wrong. Water vapor from the insulation material would accumulate on the detector and freeze into a thin layer of ice. Periodic defrosting of the detector by heating it to 220 K ( - 63° F) removed the ice layer. The defrosts were never routine, however. "We would go into focus once every two weeks and would start to defrost 12 hours before," Holt said. "We would be terrified each time that the command system wouldn't work and would have to wait until the next pass over the ground station to see if it had worked, or whether we had a bomb, a complete failure." The system always worked, though, and got better as time went on.

The High Resolution Imager presented problems of a different type. Unlike the other instruments, which were adaptations of devices that had operated in other applications, there was no previously existing prototype. Steve Murray, Patrick Henry, Edwin Kellogg, Harvey Tananbaum, and Leon Van Speybroeck, all of Smithsonian Astrophysical Observatory, developed the instrument. The first few tries did not work. Finally, Murray came across an article by a group of scientists at the University of Leicester in Great Britain. The article described a type of detector that looked promising. Two of these scientists, Kenton Evans and Ken Pounds, brought a prototype unit. It was set up and tested. It did not work. Evans and Pounds said that the unit worked at home. Finally, the problem was traced to an inadequate approximation in the computer program that was used to process the results and to vacuum pumps that were putting noise into the system. The Smithsonian group then set up a laboratory and built a high resolution X-ray camera based on the principles of the British instrument. In the words of Steve Murray, "We just kept trying things until something worked. We really played the basement inventors. It took a few years, but after going down many blind alleys, finally we succeeded. In the end it turned out that the simplest ways were the ways that worked." For example, the detector [66] required a grid of wires that had to be wound 128 wires to the inch, evenly spaced. How to space them evenly? Wind a double strand of wire and then unwind one strand.

The next step was to test the High Resolution Imager on a rocket flight. This led to a spectacular series of rocket failures unrelated to the quality of the detector. On one flight a relay failed; on another the doors did not open; on yet another a switch did not work. Finally, in July 1978, only a few months before launch, they had the one and only successful flight test of the detector.

The heart of the observatory was the mirror assembly. Leon Van Speybroeck of the Smithsonian Astrophysical Observatory assumed primary responsibility for the development of the mirror assembly. Because of their short wavelength and high energy, X-rays encountering a mirror or lens at a large angle would not be reflected but would slam into the surface and be absorbed, in much the same way as a stream of bullets encountering a wooden wall. However, just as bullets hitting the wall at a grazing angle would ricochet, so too can X-rays impinging at grazing angles on polished glass mirror surfaces be reflected with high efficiency to form an image. These X-rays are recorded on one of the detectors at the focus of the telescope and converted to electric signals that are recorded on magnetic tape and transmitted to Earth when the observatory passes over one of the ground stations.

 


At the Einstein Observatory Data Center at the Harvard-Smithsonian Center for Astrophysics, Rick Harnden studies the X-ray image of the Crab Nebula, the remnant of an exploding star.

At the Einstein Observatory Data Center at the Harvard-Smithsonian Center for Astrophysics, Rick Harnden studies the X-ray image of the Crab Nebula, the remnant of an exploding star. (Photo by Dane Penland; Smithsonian Institution Photo No. 80- 16232)


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Schematic of HEAO 3.

Schematic of HEAO 3.

 

Allan Jacobson

Allan Jacobson

 

The mirrors were made at Perkin-Elmer Corporation by a team headed by P. Young. First, the mirror elements were diamond ground to approximate shape. Then they were polished, coated with chromium and nickel, aligned, and bonded to a support structure. This was no trivial problem. The mirror elements, which weighed a few thousand pounds, had to be supported in such a way as to mimic the gravity-free state of orbit. The Perkin-Elmer engineers, together with Gerry Austin and William Antrim of AS&E, developed a scheme of 32 counterweights placed so that the mirrors essentially floated and assumed their unconstrained, gravity-free state.

[68] The difference in the way that X-rays are reflected means the design of the X-ray telescope must be different from an optical telescope, which uses flat dishes to reflect light. Instead, the X-ray telescope used an array of four nested glass tubes. The surfaces of these mirrors had to be polished internally, a technically much more difficult task than polishing conventional telescope mirrors. Even more worrisome was the lack of a conventional method to measure the smoothness of the surface. No rough spots on the surface greater than about 30 angstroms, that is, about one ten-millionth of an inch, could be tolerated. Getting the smoothest possible surface was critical, because if the surface is rough, it scatters the radiation and smears the image. The smoothness of conventional mirrors could be measured by studying the interference of light waves scattering off the mirror. This was not possible for the nested X-ray mirrors. The solution was to put a piece of transparent plastic tape on the mirrors, make an impression, and then run the tape through the interference machine.

Another problem was to measure the roundness of the mirrors. The mirrors were very flexible and would deform under their own weight. A small speck of dust on the measuring table would cause the measure of the roundness of the mirrors to vary from time to time. Finally, Van Speybroeck came up with a solution: float the mirrors in a vat of mercury during the measuring process. NASA was skeptical, so Van Speybroeck found a quantity of mercury left over from a colleague's experiment and demonstrated the feasibility of his idea with a prototype, after which NASA agreed to do it with the Einstein Observatory mirrors.

Finally, the mirror assembly and the detectors had to be integrated into a single observatory and tested. This testing took place late in the summer of 1977. A calibration facility had been built at Marshall Space Flight Center especially for testing the Einstein Observatory. This facility included vacuum pumps, a 1000-foot-long pipe to provide the separation between source and telescope that was needed to permit effective focusing, a vacuum chamber to house the observatory, and an adjustable source of X-rays to direct onto the telescope. Originally, six months had been allotted for testing of the observatory, but because of a six-month slip in schedule, NASA shortened the testing period to one month. Giacconi protested. One month was simply not enough time to make the more than a thousand separate measurements that were needed to make sure the observatory would work in orbit. But one month is all they would get, so they came up with an alternative plan. They would work 24 hours a day, in two overlapping 13-hour shifts. To ensure that the work was done as efficiently as possible, Van Speybroeck developed a computer program to optimize the testing. A schedule of 1397 separate tests was developed, and time was set aside for reworking hardware problems and retesting. This reserve turned out to be very important, as several problems did arise, and potentially serious inflight problems were avoided.

 


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Gamma Ray Spectrometer, HEAO C- 1. The Gamma Ray Spectrometer consisted of a cluster of four cooled, high-purity germanium detectors in a cesium-iodide sodium-activated shield. The germanium crystals are cooled by a solid cryogen refrigerator. The goal of the experiment was to explore for sources of X-ray and gamma ray line emissions. The instrument measured the spectrum and intensity of both diffuse and discrete sources of X- and gamma radiation. It also measured the isotropy of the diffuse background as well as time variations in the gamma ray flux from discrete sources.

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Gamma Ray Spectrometer, HEAO C- 1. The Gamma Ray Spectrometer consisted of a cluster of four cooled, high-purity germanium detectors in a cesium-iodide sodium-activated shield. The germanium crystals are cooled by a solid cryogen refrigerator. The goal of the experiment was to explore for sources of X-ray and gamma ray line emissions. The instrument measured the spectrum and intensity of both diffuse and discrete sources of X- and gamma radiation. It also measured the isotropy of the diffuse background as well as time variations in the gamma ray flux from discrete sources.

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Gamma Ray Spectrometer, HEAO C- 1. The Gamma Ray Spectrometer consisted of a cluster of four cooled, high-purity germanium detectors in a cesium-iodide sodium-activated shield. The germanium crystals are cooled by a solid cryogen refrigerator. The goal of the experiment was to explore for sources of X-ray and gamma ray line emissions. The instrument measured the spectrum and intensity of both diffuse and discrete sources of X- and gamma radiation. It also measured the isotropy of the diffuse background as well as time variations in the gamma ray flux from discrete sources.

Gamma Ray Spectrometer, HEAO C- 1. The Gamma Ray Spectrometer consisted of a cluster of four cooled, high-purity germanium detectors in a cesium-iodide sodium-activated shield. The germanium crystals are cooled by a solid cryogen refrigerator. The goal of the experiment was to explore for sources of X-ray and gamma ray line emissions. The instrument measured the spectrum and intensity of both diffuse and discrete sources of X- and gamma radiation. It also measured the isotropy of the diffuse background as well as time variations in the gamma ray flux from discrete sources. The Principal Investigator was Allan Jacobson of NASA's Jet Propulsion Laboratory in Pasadena, California.

 

An important by-product of the calibration of the observatory was the development of the computer software to analyze the large volume of data generated in the testing. This efficient data handling system was developed largely by Christine Jones, William Forman, Arnold Epstein, Jonathan Grindley, Jeffrey Morris, Schreier, and Van Speybroeck of the Smithsonian. It formed a basis for the data handling system used to reduce and.....

 


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Isotopic Composition of Primary Cosmic Rays Experiment, HEAO C-2.

[see also picture below] Isotopic Composition of Primary Cosmic Rays Experiment, HEAO C-2. Flash tube arrays defined the trajectory of incident particles through the detectors, which were powder Cerenkov counters. The indices of refraction of the counters were chosen to maximize the useful observation time for the geomagnetic cutoff associated with the orbit of the observatory. This experiment measured the isotopic composition of primary cosmic rays with atomic charge z in the range of 4 (beryllium) to 56 (iron) and m the momentum range 2 to 20 billion electron volts per nucleon. In addition, the charge resolution of the instrument allowed identification of all incident nuclei up to charge z = 50 (tin). The Principal Investigators were Lydie Koch-Miramond of the Center for Nuclear Studies, Saclay, France, and B. Peters and I. Rasmussen of the Danish Space Research Institute, Copenhagen, Denmark.

 

....analyze the data after the launching of the observatory. It is an efficient thoroughly "de-bugged" system that allows one to go smoothly from observation to data analysis and is likely to be the prototype for future astronomical data handling systems.

The launch of HEAO 2 was scheduled for shortly after midnight on November 13, 1978. As usual, the scientists were skittish about readiness of the launch vehicle. The good track record of the Atlas-Centaur system was....

 


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Isotopic Composition of Primary Cosmic Rays Experiment, HEAO C-2.


 

.....reassuring, to a point. "But we had only one instrument," Harvey Tananbaum said, "so there were no second opportunities. That launch vehicle didn't have to be good. It had to be perfect. I think they (the launch team) were a little miffed with the aggressiveness with which we were questioning them. I must say that everything did go smoothly, so I guess their reassurances were well founded. It was just that we had so much invested that we felt we had the right to know about every questionable area."

To protect this right, Giacconi sat in the control area with the NASA officials, so he would have final okay for the experiments in case questions arose about the vehicle or the conditions. Pat Henry, who had followed the experiment after calibration on through Marshall and integration with the spacecraft at TRW, was at Giacconi's side. The countdown moved forward without a hitch. At T minus 20 seconds, Henry gave up his seat in the control room and ran outside to see the launch. Harvey Tananbaum was watching from the bleachers. "I felt a chill run through my body when I saw the tower light up at T minus I with ignition. It was like lightning and thunder. You couldn't hear anything for several seconds. By then the vehicle had already lifted off. It began to rise very, very slowly, gathering speed. You momentarily forgot that it was carrying your life's work, as it were, under the nose cone."

A few minutes later the report came in that HEAO 2 had achieved orbit. Cries of jubilation. A sigh of relief from Fred Speer. And a deep sense of satisfaction for everyone involved. Almost immediately these feelings were replaced with nervous anticipation about activation of the instruments a few days later. In the words of Ethan Schreier, "everyone was completely [72] wired. No one could sleep until we arrived at Goddard. For the next six days I must not have slept more than 15 or 20 hours."

The first step was to check the star trackers. Much to the horror of the scientists, they appeared to be malfunctioning. "We turned them off and sat there for four days, trying to figure out what was wrong," Schreier recalled. "Then we realized that the star trackers were picking up the reflection of the moon off the ocean, and that there was no problem." Then it seemed that the pointing system was not working. "We found very large drifts," Schreier said. "Everyone was going bananas." By studying the data, they concluded that the star trackers were off by a few percent. They consulted the manufacturers, who studied the data from the star trackers and confirmed that they were working perfectly. The effect was traced to a memorandum written years ago in which the number 32 767 had been approximated as 32 000 in a conversion formula.

Finally, four days after the launch, the spacecraft slewed to Cygnus X-l, a strong X-ray source thought to be associated with a black hole. It was time for the moment of truth, the moment of "first light." For Leon Van Speybroeck that first X-ray image, which showed that the mirrors and the imager were going to work, was "almost like a religious experience." For Rick Harnden, the first light through the Imaging Proportional Counter was a moment of anxiety bordering on panic and despair. The Imaging Proportional Counter was viewing a portion of the sky thought to contain the solitary source Cygnus X-3, yet a multiple image appeared. "My first thought was, 'Oh, no! It doesn't work!"' As it turned out, the detector was working just fine. It had discovered a group of previously undetected sources in the vicinity of Cygnus X-3. The other instruments worked well, too. With a successful mission almost guaranteed, the observatory was nicknamed the Einstein Observatory, in honor of the centennial of the birth of the man whose theories of space, time, and matter so radically altered our perception of the universe. After more than a decade and a half of planning, politics, and persistence through the solution of what Tananbaum remembered as "a hundred thousand technical problems of one kind or another," Riccardo Giacconi's dream of a large orbiting X-ray telescope had come true.

While the Einstein Observatory was sending back stunning X-ray images of exploding stars and galaxies and clusters of galaxies, preparations were being made to launch HEAO 3, an observatory that would probe the universe at even higher photon energies and would capture samples of high energy particles from interstellar space. HEAO 3 was similar to HEAO 1 in that it was a survey mission involving several independent but complementary instruments. The restructuring of the HEAO program had forced a marriage of three experiments into one experiment designed to observe rare high atomic number cosmic rays. The Principal Investigators on the new experiment were Martin Israel, Edward Stone, and C.J. Waddington. It was a....

 


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The Heavy Nuclei Experiment, HEAO C-3.

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The Heavy Nuclei Experiment, HEAO C-3. This cosmic ray experiment consisted of two large ionization chambers mounted back to back with a large Cerenkov counter between. It observed rare, high atomic number (z less than 30), relativistic nuclei in the cosmic rays. The instrument measured the elemental composition and energy spectra of these nuclei with sufficient resolution to determine the abundance of individual elements from chlorine (z = 17) through at least uranium (z = 92). The Principal Investigators were Martin Israel of Washington University, St. Louis, Missouri, Edward Stone of the California Institute of Technology, and C. J. Waddington of the University of Minnesota, Minneapolis. Shown with the experiment is Harold Kinney of Ball Brothers Aerospace.

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The Heavy Nuclei Experiment, HEAO C-3.



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All the data collected by HEAO 3 passed through the main junction box shown here.

All the data collected by HEAO 3 passed through the main junction box shown here.

 

....marriage of convenience, brought about primarily by budgetary considerations, but by all accounts it was a highly successful union. "The collaboration resulted in a better experiment," said Martin Israel, "because it brought together three different approaches to studying cosmic rays." This made it possible for the experimenters to unambiguously determine both the nuclear charge (atomic number) and momentum of a cosmic ray particle.

The Israel-Waddington-Stone Heavy Nuclei Experiment was one of two cosmic ray experiments on HEAO 3. The other was an experiment designed to measure the isotopic composition of cosmic rays. It was a collaboration between scientists and the Center for Nuclear Studies in Saclay, France, and the Danish Space Research Institute in Copenhagen, Denmark. With the French group there was another collaboration which came about not because of budget, but because of the keen eye of a young physicist. At the heart of the French-Danish proposal were counters that required a liquid without bubbles and freon gas at very high pressure. Such a counter was [75] proving very difficult to build, and the scientists were worried about being able to develop the required technology in time. As Lydie Koch-Miramond remembers it, "there was this young physicist, Michel Casse, who was interested in becoming part of the project. He was reading through the journals and preprints in the library when he came across a doctoral thesis in applied chemistry. The thesis dealt with a method of growing transparent silica gels. He thought that it could work for our counters. We went to Lyon, talked to the chemist, and began a collaboration that led to a successful counter. If he had not read that thesis, we probably wouldn't have made the second selection [the selection after restructuring] for HEAD."

If HEAO 3 was blessed with serendipitous partnerships, it was also plagued by eleventh hour problems. Within a week of delivery, 100 amplifiers were destroyed in final thermal vacuum testing of the Heavy Cosmic Ray Nuclei experiment. The problem was quickly traced to a faulty testing procedure, so there was no concern about the amplifiers failing in orbit. Nor would it be particularly difficult to replace the destroyed amplifiers. But what about the thousand or so amplifiers that were not destroyed? Were they damaged to the point that they might fail? The only solution was to take them out, test them, and put them back in again. This involved breaking and remaking over one hundred thousand connections or welds.

Then, just four months before launch, the Gamma Ray Spectrometer developed "thermal excursions." In other words, the instrument, designed to operate at 80 K (-315° F), was from time to time heating up to 120 K ( - 243° F). Under the direction of Allan Jacobson, the Principal Investigator, a "tiger team" of problem solvers was convened, with Frank Schutz as manager and Jim Stephens handling the technical leadership. Their conclusion: the instrument would have to be taken apart. Working sixteen hours a day all through the summer, scientists, engineers, and technicians from the Jet Propulsion Laboratory, TRW, and Ball Brothers Aerospace in Boulder, Colorado, disassembled the instrument and found the problem. A washer had not been squeezed flat by its companion bolt. The result had been a less that perfect seal that caused the thermal excursions.

The seal was repaired, and the Gamma Ray Spectrometer was rushed by Military Air Transport to the Kennedy Space Center launch site, where it was installed in the spacecraft just hours before the Center was evacuated in preparation for Hurricane David. Two weeks later, on September 20, 1979, HEAO 3, the last of the HEAOs, was successfully launched. A few days later the instruments were turned on, and it was clear that the mission would be a success.

Some of the many scientific successes of the HEAO program will be discussed in the chapters that follow. The point to be made here is that it was also a tremendous technological success. As Frank McDonald said, "HEAO showed that you could put together very large experiments that in [76] many cases exceeded expectations of design." And it was done within 20 percent of the original cost estimate, an amazing feat considering the complexity of the project and the fact that the consumer price index for commodities and services increased by more than 50 percent over the same period.

HEAO worked in part because it was well planned and well managed. But most of all it worked because of the talent and the extraordinary dedication of the individuals involved. And the dedication of their families, who must have wondered sometimes if all the long hours, the lost weekends and vacations, and the distracted, worried looks across the dinner table were really worth it. "We had to get a lot out of people through perseverance, argument, and friendships forged during the years of the project," recalled Steve Murray. "A lot of times the engineers went the extra mile with us simply because they were our friends." Friendships were part of it, to be sure, but they were not the driving force that kept these people working overtime without pay day after day for years. Friendships could not explain why Harold Kinney, a mechanical technician on HEAO 3, could say, "there...

 


Ball Brothers Aerospace workers reinsert the repaired cryostat into the Gamma Ray Spectrometer refrigerator.

Ball Brothers Aerospace workers reinsert the repaired cryostat into the Gamma Ray Spectrometer refrigerator.


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September 20, 1979. The launch of HEAO 3.

September 20, 1979. The launch of HEAO 3.

 

[78] ...was not one morning during the whole project that I didn't want to come to work." What could explain it?

Dozens of scientists and engineers involved with the HEAO program were asked this question. Their responses were almost all the same and related to two deep-seated human desires: the desire to solve problems and the desire to be a part of something larger than themselves. "The most gratifying thing was to solve the problems," said Harvey Tananbaum. "There was no finger pointing as to why the problems had arisen, just recognition that a tremendous problem had been solved. Everyone was working together." Dick Halpern summed up the feeling: "I was once asked who was most responsible for HEAO's success and I couldn't answer. Hundreds of people worked on the project. Sure, I knew many, many of them-but all of them felt responsible-and they all were." And finally, as Art Gneiser of Ball Brothers put it, "It's an incredible feeling of satisfaction to see the data come in, bringing information about the universe out there, and to know that a lot of yourself is up there and that it's all working."


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