Explorer 1: Gateway to the Never Ending Wonders of Space Science

The Space Studies Board Van Allen Lecture

delivered by

Frank B. McDonald

Institute for Physical Science and Technology

University of Maryland

PREFACE

On June 26, 2008, on the occasion of the 50th anniversary of the Space Studies Board, Dr. Frank McDonald delivered the first Space Studies Board Van Allen Lecture. The following is excerpted from the transcript of this lecture and is intended to convey, in his words, the thoughts that Dr. McDonald shared with us on that evening.


Lennard A. Fisk

Chair, Space Studies Board

(2003–2008)

INTRODUCTION

I am very pleased to accept the Van Allen Award of the Space Studies Board, and to deliver the Van Allen Lecture this evening. I received my Ph.D. in 1953 from the University of Minnesota and then joined Van Allen’s group at the University of Iowa from 1953 through 1959. Van Allen was an exceptional mentor. He paid close attention not only to me but all the other people that were in his group and gave us the support that we needed. He kept encouraging me to follow the right path in spite of a tendency I had to wander about a bit.

I remember a great deal about those early days in the space program, and the impact and advice that I received from Van Allen. I am pleased to be able to share some of those experiences with you tonight. NASA has been one of the great adventures in my life. I am so lucky to have seen the beginning of the space age with Van Allen. I saw Explorer 1 and 3. I was able to get my own programs going at the Goddard Space Flight Center, starting in 1959 when Goddard first opened. Even today, I am still looking at Voyager data. NASA has been really one of the world’s most exciting places to be, and so in addition to describing how we began, I want to share some thoughts concerning where the space program is going in the immediate future.

I have also witnessed, as we all have, the tremendous impact of satellites on our lives. If we looked out tonight and we could count the satellites in the sky, we would find on the order of 875 satellites. Most are communications satellites, 15 percent are used for scientific purposes: Earth sciences, astrophysics, space physics, and planetary physics. If we consider only Earth and space science satellites by country, we find that from Europe there is on the order of 40 satellites. Here in the United States there are 52. China comes in third, with 21. Space science is predominantly an American and European endeavor.

Satellites have had an enormous impact on our lives. Just imagine if you would take them away, how the military would function and how other areas of our society would function. It would be a great loss. These 875 satellites are a routine part of our lives, so much so that when there is a major launch you might read about it in the trade journals, e.g., in Aviation Week, but you probably will not find a mention of it in the Washington Post.



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Explorer 1: Gateway to the Never Ending Wonders of Space Science The Space Studies Board Van Allen Lecture deliered by Frank B. McDonald Institute for Physical Science and Technology Uniersity of Maryland PREFACE been one of the great adventures in my life. I am so lucky to have seen the beginning of the space age with On June 26, 2008, on the occasion of the 50th anniver- Van Allen. I saw Explorer 1 and 3. I was able to get sary of the Space Studies Board, Dr. Frank McDonald my own programs going at the Goddard Space Flight delivered the first Space Studies Board Van Allen Center, starting in 1959 when Goddard first opened. Lecture. The following is excerpted from the transcript Even today, I am still looking at Voyager data. NASA of this lecture and is intended to convey, in his words, has been really one of the world’s most exciting places the thoughts that Dr. McDonald shared with us on to be, and so in addition to describing how we began, that evening. I want to share some thoughts concerning where the space program is going in the immediate future. Lennard A. Fisk I have also witnessed, as we all have, the tremen- Chair, Space Studies Board dous impact of satellites on our lives. If we looked out (2003–2008) tonight and we could count the satellites in the sky, we would find on the order of 875 satellites. Most are com- INTRODUCTION munications satellites, 15 percent are used for scientific purposes: Earth sciences, astrophysics, space physics, I am very pleased to accept the Van Allen Award of and planetary physics. If we consider only Earth and the Space Studies Board, and to deliver the Van Al- space science satellites by country, we find that from len Lecture this evening. I received my Ph.D. in 1953 Europe there is on the order of 40 satellites. Here in from the University of Minnesota and then joined the United States there are 52. China comes in third, Van Allen’s group at the University of Iowa from 1953 with 21. Space science is predominantly an American through 1959. Van Allen was an exceptional mentor. and European endeavor. He paid close attention not only to me but all the other Satellites have had an enormous impact on our people that were in his group and gave us the support lives. Just imagine if you would take them away, how that we needed. He kept encouraging me to follow the military would function and how other areas of our the right path in spite of a tendency I had to wander society would function. It would be a great loss. These about a bit. 875 satellites are a routine part of our lives, so much I remember a great deal about those early days in so that when there is a major launch you might read the space program, and the impact and advice that I re- about it in the trade journals, e.g., in Aiation Week, ceived from Van Allen. I am pleased to be able to share but you probably will not find a mention of it in the some of those experiences with you tonight. NASA has Washington Post. 12

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12 FORGING THE FUTURE OF SPACE SCIENCE THE EARLY PIONEERS He was left profoundly deaf at the age of 10 from scar- let fever, but he still read widely. At age 16, his parents Let us begin in the beginning and trace the activities of sent him to Moscow for study, where he existed on the people who put the space age into motion. brown bread. The librarian at the main library provided In the very beginning there was Isaac Newton, who him with a place for him to work, so that at age 19 he taught us the Laws of Motion. Force equals mass times was able to become a high school teacher. In the early acceleration; to every action there is always opposed an 1900s, he published a number of articles, science fan- equal reaction. Newton’s objective was to understand tasies. However, in 1903, he published his significant Kepler’s Laws, to understand the motion of planets article in a Russian science journal: Exploring Space and the Moon. To make his life easier, he also invented with Reactive Devices. calculus. In the center of Figure 9.1 is Herman Oberth, The modern day icons of the space age were who at the age of 12 read Jules Vern and was strongly Konstantin Tsiolkovsky, Herman Oberth, and Robert influenced by him; indeed all three of the space icons Goddard, who are shown in Figure 9.1, along with their were influenced by Jules Vern. Oberth’s parents sent immediate scientific descendants: Sergey Korolyov in him off to study Medicine at the University of Munich. the case of Tsiolkovsky; Wernher Von Braun in the He did not like that, so he went to Heidelberg, where case of Oberth, and all the American space program, he wrote a Ph.D. thesis on interplanetary travel. It was symbolized by NASA/JPL, from Goddard. not accepted by Heidelberg so he never officially got Tsiolkovsky was born in a small village south of his degree. In 1923, he wrote a book, Rockets into In- Moscow; he had a Polish father and Russian mother. terplanetary Space, which sold surprisingly well. Oberth Konstantin Tsiolkovsky Hermann Ober th Rober t H. Goddard Sergey Korolyov Wernher Von Braun Jet Propulsion Laboratory FIGURE 9.1 The three icons and their descendents. Left to right, top row: Konstantin Tsiolkovsky (NASA), Hermann Oberth (courtesy 9.01a-e combined.eps of the Hermann-Oberth-Spaceflight Museum, Feucht, Germany), and Robert H. Goddard (NASA). Left to right, bottom row: Sergey Korolyov (NASA), Wernher Von Braun (courtesy of NASA/MSFC), and the Jet Propulsion Laboratory (NASA).

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12 EXPLORER 1: GATEWAY TO THE NEVER ENDING WONDERS OF SPACE SCIENCE had a great effect on Wernher Von Braun, who we will w as doing. Lindburgh went to Harry and David discuss later. Guggenheim and got funding for Goddard, at the rate Robert Goddard, on the right of Figure 9.1, was of $25,000 a year for 4 years. Back in the early 1930s, also very interested in space. He received his Ph.D. $100,000 was a lot of money, so Goddard picked up and from Clark University, after which he went to Princ- moved from Massachusetts to Roswell, New Mexico, eton University where he developed tuberculosis and before we had all the flying saucers there. There he de- then returned home to continue his research at Clark. veloped the liquid propellant rocket, occasionally blow- He submitted a proposal to the Smithsonian, which ing it up, but eventually getting it to reach an altitude awarded him $5,000 to support his research. He pub- around 9,000 feet. The Caltech folks and Frank Malina lished his research in 1921: A Method of Reaching from JPL went to visit Goddard, but he would not show Extreme Altitudes. Interestingly, he discussed at the Malina the rockets that he had. He did let Malina into end of that paper how he might send an object to the his shop but would not uncover the rocket that he was Moon, and then impact it with some flash powder that putting together. Goddard just did not play well with you could see from Earth. JPL is shown in Figure 9.1 others, but he was a great pioneer of the space age. as a descendant of Goddard, but in reality there was a very negative interaction between the two. JPL could THE GERMAN ROCKET PROGRAM OF never work with Goddard; he simply wanted to have WORLD WAR II AND THE BEGINNING his own show. OF THE U.S. ROCKET PROGRAM Oberth wrote to Goddard and asked him for a copy of his 1921 paper, a Method of Reaching Extreme In the meantime, back in 1929, the Germans made a Altitudes. Goddard reluctantly sent it, but gradually decision that they wanted to have what would come there emerged a conflict. The Germans claimed that to be known as Intermediate Range Ballistic Mis- Oberth had done it before Goddard, for which there is siles. They turned the task over to Captain Walter no evidence. The Russians pointed out that Tsiolkovsky Domberger, who recruited Wernher Von Braun, and published back in 1903, two decades before Goddard they put together a rocket team and opened up a rocket and Oberth, and to reinforce their point they raised the test sight in Peenemunde, in September 1941. The war status of Tsiolkovsky, who had lived in total obscurity at that time was going well for the Germans, and so up to that point. The Soviets elected him to the fore- Hitler cut back on their budget and they limped along, runner of the Soviet Academy of Sciences, gave him a developing what would become the A7. generous pension, and he was supremely happy. However, as the war worsened for the Germans, A famous New York Times editorial on January 13, they received increased funding for a production rocket, 1920 made the cutting statement that Goddard did the V2 shown in the center panel of Figure 9.2, which not know the relation of action to reaction, stating they produced by using concentration camp labor. The that you have to have something better than a vacuum rockets were reasonably successful in their flight his- against which to react. It noted that Goddard should tory. The V2 rockets did some damage to England, have learned this in high school. It was one of the most and some 5500 people were killed. More than 12,000 cutting editorials and damaged Goddard’s self-esteem of the concentration camp laborers died. It was really greatly. At least in July 1969 when Apollo 11 was mak- an inhumane exploitation of these people that went ing its way to the Moon, the New York Times put out a beyond anything I think we can imagine. retraction and said, “Further investigation and experi- The development of the V2 was the beginning of mentation have confirmed the findings of Isaac Newton the modern Intermediate Range Ballistic Missile. At and it is now definitely established that a rocket can the end of the war, the U.S. scooped up the rockets, function in a vacuum as well as in an atmosphere.” One the parts, the drawings, and the people, in Operation can argue that the media should stay out of things they Paperclip. They brought 100 rockets to Whitesands do not understand. and the Naval Research Laboratory (NRL) convinced Goddard did receive support from Charles the U.S. Army that they should launch payloads—that Lindburgh who was very impressed with what Goddard the Army had a need to learn about what the upper

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10 FORGING THE FUTURE OF SPACE SCIENCE Ernst Stuhlinger APL Upper Atmosphere Research V-2 rocket Wernher Von Braun Group FIGURE 9.2 Ernst Stuhlinger (courtesy of Patricia Miklik Doyle); Applied Physics Laboratory (APL) Upper Atmospheric Research Group (courtesy of Johns Hopkins University APL); V2 rocket (courtesy of NASA Glenn Research Center); Wernher Von Braun (courtesy 9.02a-d combined.eps of NASA/MSFC). atmosphere was like. Ernst Stuhlinger, also shown in This was Operation Paperclip and its successor Figure 9.2, was part of Von Braun’s group and had done programs. In the end some 67 V2s were fired. The V2s his PhD thesis on the development of Geiger coun- were followed by the Aerobee rocket, which could take ters. He became the scientific liaison to the scientific a 100-pound payload through a 76-kilometer trajec- community. tory. The Aerobees were made by Aerojet under the Shown in the lower left hand corner of Figure supervision of Von Kármán and Frank Malina of JPL, 9.2 is Jim Van Allen, looking as young as always, with and were eventually operated by NRL. The Aerobee a large group. At that time, he was with the Johns was a revised version of the Corporal rocket. It steadily Hopkins University Applied Physics Laboratory and, improved over the years and some 1037 Aerobees as one might expect, when he came to town to fly the were fired. first rocket, he had his experiment ready and he flew it. Unfortunately, the rocket failed, but he did eventually VAN ALLEN AND ROCKOONS get a successful flight, number 33. At the same time, Eric Crowther organized a rocket panel to distribute Let’s return now to Van Allen. On the left of Figure 9.3 the V2 resources but he left shortly to go into industry. is Van Allen as a graduate student, at what is now the Van Allen took over as chairman of the group that University of Iowa. The middle shot, shows him as a evolved into the Rocket Upper Atmospheric Research Lieutenant in New Guinea. Van Allen worked first at Panel, finally the Rocket and Satellite Research Panel. the Carnegie Institute on the proximity fuse, and so Van Allen remained Chairman until NASA was estab- he was one of the people who was sent to the Pacific lished, and then the group dissolved. The Rocket Panel to introduce the rocket to the Navy. The photo on the did not receive support from anybody. It met roughly right is Van Allen at his desk at the University of Iowa three times a year and it was made up of people from at the end of his career. universities, government laboratories, and industry. One of the technologies that Van Allen developed

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11 EXPLORER 1: GATEWAY TO THE NEVER ENDING WONDERS OF SPACE SCIENCE FIGURE 9.3 Dr. Van Allen (left to right) as a graduate student (NASA), as a lieutenant in the Navy (NASA), and at his desk (courtesy of Tom Jorgensen, University of Iowa Office of University Relations, 1990). 9.03a-c combined.eps while in the Navy, an idea he got from Lee Lewis, a The Rockoon program was great fun, but it had its Commander in the Navy, was the Rockoons. As shown moments that established that we really were not rocket in Figure 9.4, these were rockets that were launched scientists. The photo on the right shows some idiot up from a balloon. The balloon takes the rocket to about there (me) holding a two-stage rocket that we decided 70,000 feet, and you are able to achieve 350,000 feet to try. We used the same nose cone and the same tail when the rocket fired. fins that we used on smaller rocket flights. The rocket FIGURE 9.4 R ockoons. SOURCE: Courtesy of NASA. 9.04a-b combined.eps

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12 FORGING THE FUTURE OF SPACE SCIENCE was carried by the balloon to 70,000 feet. It fired, the ball into the future is cloudy, two things seem clear: second stage fired, and everything went blank. We did “A satellite vehicle with appropriate instrumentation that twice. Then JPL told us that although the rocket can be expected to be one of the most potent scien- may be at 150,000 feet or so, it still has a great deal tific tools for the 20th century. The achievement of a of heating that will burn through the tail fins and the satellite craft by the United States would inflame the nose cone. imagination of mankind, and would probably produce Three or four days later, the small rocket that is repercussions in the world comparable to the explosion on the top of the rocket exploded on deck, severely of the atomic bomb.” Neither of these statements were injuring our Navy representative who is up there, right over-statements by any stretch of the imagination, as behind me. We got him to shore, he made a complete proved to be the case when the Soviets launched a satel- recovery but I had to come down to Washington and lite first, and there were worldwide repercussions that face the Navy. I must say in all of my years, I have never the Soviets were ahead of us. been dressed-down quite as strongly as they did. And Starting in 1954, with the development of ICBMs, with me already feeling very badly about the whole it became obvious that a satellite could be launched if thing. There were roughly 100 Rockoon flights in six you had the will to do it. The U.S. proposed through expeditions started in 1952, and they were great fun. A its International Geophysical Coordination (IGY ) lot of the experiments were done, ionization chambers, committee that they would launch a satellite during the single Geiger counters, double and the shielded Geiger IGY period in 1957 to 1958, and the Soviets came back counters; the same experiments that we would later fly saying they too were going to launch a satellite. We on satellites. were distinctly told what their intentions were. They were going to launch Sputnik, as shown in Figure 9.5. Our reaction was one of surprise and dismay, as shown THE FIRST SATELLITES by the strong reaction in Life Magazine. There was a very interesting study done in 1946 by the The Soviet who made Sputnik happen was Sergey RAND project that stated that although the crystal Korolyov, who had spent World War II in a Soviet THE SATELLITE WHY REDS GOT IT FIRST WHAT HAPPENS NEXT FIGURE 9.5 Left to right: Sputnik 1 (courtesy of NASA National Space Science Data Center); Smithsonian Observatory scientists working at Massachusetts Institute of Technology trying to calculate Sputnik’s orbit, cover of LIFE magazine, October, 21, 1957 (photo by Dmitri Kessel/Life Magazine, Copyright Time Inc./Time Life Pictures/Getty Images); and Sergey Korolyov (courtesy of NASA). 9.05a-c combined.eps

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1 EXPLORER 1: GATEWAY TO THE NEVER ENDING WONDERS OF SPACE SCIENCE Gulag. One of his so-called friends but really rivals JPL, for JPL to build the spacecraft. There was thus a had claimed he was giving information to the enemy. JPL spacecraft and upper stage, Van Allen’s University He was sentenced to the Gold Mines in Siberia. His of Iowa experiment, and the main rocket provide by von thesis advisor arranged for him to be assigned to the Braun. This was Explorer 1, launched on January 31, place where they were doing design work for rockets, 1958, shown in Figure 9.6 beside the famous celebra- and he put together the ICBM, the R7 that was flown tory photo of Pickering, Van Allen, and von Braun. twice successfully as an ICBM before Sputnik. Shown in Figure 9.7, in the upper left hand corner, There were many people in Washington who wor- is the counting rate of Van Allen’s Geiger counter on ried what would happen if the U.S. launched a satellite Explorer 3. Explorer 1 did not have a tape recorder, first and over-flew Russia. They did not know what the since the spin rate was too high. George Ludwig had Soviet reaction would be. It was convenient that the to redesign the tape recorder, and is shown in the fig- Soviets used an ICBM to launch Sputnik. However, the ure with his redesigned tape recorder, along with Ed appreciation of letting the Soviets clear up the policy Foran, the main machinist at Iowa. It is curious that issues was lost on the general public, who were alarmed Ed Foran’s father had worked for Robert Goddard back by the Soviet success. in New Mexico; hence a second generation of space In the U.S., the Vanguard rocket to be built by engineers. In the lower right-hand corner of Figure 9.8 NRL had been selected to launch the first U.S. satel- is shown the main team at Iowa, the gang of four: Van lite. The Germans, under Von Braun, were now safely Allen, Carl McIIwain, George Ludwig, and Ernie Ray. ensconced and happy in Huntsville. They were initially George is currently doing a detail history of this period, denied the opportunity to launch a satellite, and kept which I hope will be published shortly their program alive by doing re-entry studies. After Within the 14-month period of Explorer 1, the Sputnik, and the failure of Vanguard, they were given principle scientific instruments for nine space missions the go-ahead to launch the first U.S. satellite. General were provided by Van Allan and his group in a period Maderas, who was in charge of the Huntsville effort, Van Allen said was his busiest and the happiest period made a deal with William Pickering, the Director of of his life. The missions were Explorers 1 through 5, FIGURE 9.6 Explorer 1 was launched on January 31, 1958. SOURCES: (left) U.S. Centennial of Flight Commission, im- age courtesy of NASA; (right) courtesy of NASA/JPL. 9.06a-b combined.eps

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1 FORGING THE FUTURE OF SPACE SCIENCE The first available full orbital set of radiation data from the tape recorder on Explorer III, obtained from an interrogation over San Diego. The horizontal dashed line at 128 counts per second is the upper counting rate limit of the tape recorder system. Photograph of the Scientific Experiment for Explorer 1, with nose cone and outer shell. Carl McIlwain, James A. Van Allen, George Ludwig and Ernest Ray examining the strip charts from Explorers 1 and 3. FIGURE 9.7 Iowa. Clockwise from top left: Photograph of the Scientific Experiment for Explorer 1, with nose cone and outer shell; the 9.07a-d combined.eps first available full orbital set of radiation data from the tape recorder on Explorer 3, obtained from an interrogation over San Diego. The horizontal dashed line at 128 counts per second is the upper counting rate limit of the tape recorder system; Carl McIlwain, James A. Van Allen, George Ludwig, and Ernest Ray examining the strip charts from Explorers 1 and 3; Van Allen presented to the Smithsonian Institution a miniaturized tape recorder that is the flight spare for the one that flew on Explorer 3. All images courtesy of NASA. and Pioneers 1 through 4. Some of these missions were over ones shoulder. There was no quality control, just partial launch failures but they did gain enough altitude your own good engineering sense. to obtain orbit. Iowa obtained very useful radiation belt Explorer 4 was interesting in that there were two data from seven out of the nine missions. Imagine here concurrent H-bomb explosions connected with the at the beginning of the Space Age, Explorer 4 had two Argus test on Johnson’s Island: Two 5-mega-ton blasts Geiger counters, and an iodide scintillation counter. and a couple of smaller A-bomb tests. The Iowa group It was incredible that these instruments could be as- noticed that there was a launch opportunity, and they sembled so rapidly. There was, however, nobody to look convinced the Army, who was in charge, to launch their

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1 EXPLORER 1: GATEWAY TO THE NEVER ENDING WONDERS OF SPACE SCIENCE experiments. The H and A bomb tests generated a there for them and that is where they were going. JPL temporary electron belt, which was useful in establish- had a very rocky start for the first few years, but now, ing some of the properties of the radiation belt. This as we will discuss later, it has turned into quite a suc- was perhaps the first example of active experimentation cess story. in space. The Army ballistic missile activities in Hunts- The gang of four at Iowa split up shortly after this ville transferred to NASA in July 1960, to become string of early missions. Ludwig and eventually Ernie the Marshall Space Flight Center. They developed Ray went to Goddard. Carl McIIwain went to UCSD larger Redstone rockets for Alan Shepard’s and Gus to start up a group. Van Allen kept going at Iowa. Iowa Grissom’s suborbital manned flights and they began had shown what a University could do and the impact work on the Saturn V rocket for the manned missions it could have, and that approach to research in space to the Moon. Jupiter C was a direct descendent of the determined how science in NASA would be done. V2, and the Saturn V was simply eight Jupiter C’s put Goddard would shortly become the center of space together in a package, to give you the necessary huge science research, but it was Van Allen’s approach that lift to go to the Moon. would guide the development of Goddard’s space sci- When you add the Manned Space Flight Center, ence activities. now Johnson, to Goddard, JPL, and Marshall, you have In December 1958, JPL formally transferred to the main ingredients of today’s NASA. And it was Iowa NASA while remaining part of Caltech. This decision and its profound impact on space science, together with was facilitated by William Pickering, the Director of the Army ballistic missile activities and JPL, and what JPL, who decided that JPL would get out of develop- they achieved with Explorer 1 and 3, that paved the ing rockets, since this was not what Caltech should way for the new NASA. be doing. JPL felt the Moon and the planets were out FIGURE 9.8 Heliophys- ics. The older and current missions in flight are used as an extended observatory, enabling end-to-end surveil- lance of the Sun–Earth Con- nection. SOURCE: Courtesy of NASA.

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1 FORGING THE FUTURE OF SPACE SCIENCE 5 FIGURE 9.9 Planetary science missions. SOURCE: Courtesy of NASA. 9.09 from IGY_DC_McDonald.eps bitmap image heavily sliced THE ROAD AHEAD The extended observatory in heliophysics provides an end-to-end look at the connection between the The story to date has been inspiring. Let us now con- Sun and Earth. The Solar Dynamics Observatory will sider what lies ahead for us. launch in 2009 and replace SOHO. As we look to the As is illustrated in Figure 9.8, there are some 24 future, Solar Orbiter is to be placed in an orbit that is missions currently studying the Sun and the helio- only a few tenths of an AU from the Sun, where the sphere it creates—the discipline of heliophysics. NASA Sun is some 25 times brighter and very detailed mea- has been very generous in supporting this disciple. surements of solar phenomena can be made. There is There are the Voyagers now exploring the outer he- also to be a Solar Probe, a mission that will penetrate to liosphere; an outstanding array of solar observatories within about 10 solar radii of the Sun, through a series such as SOHO, RHESSI, and TRACE; along with of complex orbits using Venus flybys. Solar Probe will precision measurements from the near-Earth, the ACE provide us with the first direct measurements of the ac- mission. Ulysses, which has been orbiting about the celeration region of the solar wind and of the energetic poles of the Sun, is now near its end. particles that control our heliospheric environment.

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1 EXPLORER 1: GATEWAY TO THE NEVER ENDING WONDERS OF SPACE SCIENCE FIGURE 9.10 Some results from MESSENGER’s Mercury fly by. SOURCE: Courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington. 9.10a-f combined.eps Planetary science is also doing very well, as il- the martian surface, as observed by a high-resolution lustrated in Figure 9.9. There is the Dawn mission telescope from a mission in orbit about Mars. Phoenix currently en route to an asteroid, and the Juno mission will provide definitive proof of water on Mars. to be launched to Jupiter. Deep Impact collided with One of the greatest accomplishments of the space a comet to study its nucleus. New Horizon is on its age, and of the Goddard Space Flight Center, was the way to Pluto. Stardust returned material from a comet. Cosmic Background Explorer (COBE), which, as illus- Cassini is orbiting about Saturn. trated in Figure 9.13, made very precise measurements MESSENGER has flown by Mercury twice and is of the 3° black body radiation from the beginning of about to be placed into orbit. The results from the most the universe. As stated by John Mather, the Principle recent flyby are shown in Figure 9.10. Investigator on COBE, and winner of the Nobel Prize Finally there are all the missions to Mars, shown in Physics for this measurement, it is all very simple: in Figure 9.11—rovers on the surface, Phoenix in the Just a giant, very uniform explosion that started the polar regions, and the orbiters. My favorite mission is whole universe. Phoenix, which is shown in Figure 9.12 descending to In 2009, the Hubble Space Telescope will be up-

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1 FORGING THE FUTURE OF SPACE SCIENCE NASA & International Opportunities 28 FIGURE 9.11 Current Mars missions. SOURCE: Courtesy of NASA. 9.11 from IGY_DC_McDonald-3.eps bitmap image heavily sliced graded for the last time, as illustrated in Figure 9.14. the bursts and identify their origins. Short gamma- We are using Hubble exactly as astronomers have used ray bursts are from neutron star-neutron star mergers; ground-based telescopes, such as 200 inch at Palomar. long gamma-ray bursts are from massive star core They keep upgrading the instrumentation, making it collapses. much better, with new instruments that have 20 times Finally, there is the James Webb Space Tele - the resolving power. Hubble can look at the architecture scope, to be launched in 2013—a 6.5-meter-diameter of the universe, the life story of galaxies, and the birth telescope illustrated in Figure 9.16. I think it is very and death of stars. Hubble as some people describe it is appropriate to name this mission after James Webb. the world’s most successful explorer, and it is. Repairing Although not an astronomer, he was one of the best Hubble is a very difficult thing, but if all goes well, we NASA Administrators, back in the 1960s. Webb will have an outstanding new observatory. maintained a very balanced program of space explora- Swift, which is a Goddard mission and illustrated tion, aeronautics, and science. The James Webb Space in Figure 9.15, allows you to detect gamma-ray bursts, Telescope will be placed at the L2 point, a stable loca- find their precise positions, which in turn allows tion near enough to Earth so that it can make effective ground-based observatories to study the afterglow of infrared observations. It will observe the very early

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1 EXPLORER 1: GATEWAY TO THE NEVER ENDING WONDERS OF SPACE SCIENCE HiRISE Captures Image of Phoenix EDL (Illustrates synergies between MEP orbiters and landers) HiRISE Image Swaths HEIMDALL CRATER Phoenix landing site 3 sigma landing ellipse Phoenix with parachute deployed during Phoenix descent HiRISE Image will be used to: • Understand Phoenix EDL trajectory. • Unravel complex geology of landing site. Ice sublimation in the Dodo-Goldilocks trench FIGURE 9.12 Clockwise from left: HiRISE will be used to understand Phoenix EDL trajectory and unravel complex geology of landing site (MRO-HiRISE/NASA/JPL/University of Arizona); ice sublimation in the Dodo-Goldilocks trench on Mars (NASA/JPL-Caltech); HiRISE captures image of Phoenix EDL; illustrates synergies between MEP orbiters and landers (NASA/JPL-Caltech/University of 9.12a-c combined.eps Arizona/Texas A&M University). FIGURE 9.13 Cosmic Background Explorer (COBE). Significance of spectrum: Old data were wrong! Old theories explaining bad data were wrong too! Hot Big Bang explains everything here. Steady state theory (main alternative) doesn’t. It was all very “simple”—just 9.13a-b combined.eps a single, giant, very uniform “explosion” of the whole universe! SOURCES: (Left) Courtesy of NASA/GSFC. (Right) Courtesy of NASA and the COBE Science Working Group.

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10 When the astronauts leave Hubble for the last FORGING THE FUTURE OF apex SCIENCE time, it will be at the SPACE of its capabilities – better than it has ever been before. COS + STIS = Full set of tools WFC3 + ACS + NICMOS = for astrophysics Most powerful imaging ever The architecture of the universe The mysteries of dark matter and dark energy The life stor y of galaxies The birth and death of stars Recipes for building planets FIGURE 9.14 When the astronauts leave Hubble for the last time, it will be at the apex of its capabilitiesbetter than it has ever been before. The architecture of the universe (NASA/ESA/Hubble Heritage Team (STScI/AURA)/Hubble Collaboration); the birth 9.14a-I combined.eps (NASA/ESA/Hubble Heritage Team (STScI/AURA)/Hubble Collaboration) and death of stars (NASA/ESA/P. Challis and R. Kirshner (Harvard-Smithsonian Center for Astrophysics); the life story of galaxies (NASA/ESA/Hubble Heritage Team (STScI/AURA)); the mysteries of dark matter and dark energy (left to right, NASA/ESA/A. Riess (STScI); NASA/ESA/R. Massey (California Institute of Technology); NASA/ESA/R. Massey (California Institute of Technology)); recipes for building planets (left, NASA/ESA/P. Kalas, J. Graham, E. Chiang, E. Kite (University of California Berkeley)/M. Clampin (NASA Goddard Space Flight Center)/M. Fitzgerald (Lawrence Livermore National Laboratory)/K. Stelfeldt and J. Krist (NASA Jet Propulsion Laboratory); right, NASA). universe, and see the end of the dark period and first in Figure 9.17. There is a picture of Van Allen at light. It will see the assembly of the first galaxies, and the press conference for the Pioneer encounter with the birth of stars and protoplanetary systems. It will be Jupiter. Van Allen was a driving force behind the a truly incredible mission. Pioneer missions, and subtlety led the fight to redirect Pioneer 11 from Jupiter, back across the solar system, to Saturn. I was also one of the principle investigators CLOSING REMARKS on Pioneer. I soon learned after one or two of these Let me close with some remarks on the Pioneer and press conferences that the press had only two interests. Voyager missions to the outer heliosphere, shown They wanted to see Tom Gerald’s pictures of Jupiter

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11 EXPLORER 1: GATEWAY TO THE NEVER ENDING WONDERS OF SPACE SCIENCE 3 instruments Swift - BAT, γ-rays 15–350 keV - XRT, X-rays, 0.2–10 keV - UVOT, opt, 170–650 nm Rapid slewing spacecraft Launched November 20, 2004 Short GRBs: Long GRBs: NS-NS Mergers Massive Star Core Collapse GRB 050724 GRB 080319B First afterglow Brightest elliptical host naked eye: burst and identification objects from Swift in universe: - 5.5 magnitude @ 7.5 billion lt yrs FIGURE 9.15 Swift. Clockwise from top left: Swiftís three scientific instruments work together to learn as much as possible about gamma-ray bursts (NASA/GSFC); long GRBs (Pi of the Sky collaboration); short GRBs (Reprinted by permission from Macmillan Publishers Ltd: Nature, S.D. Barthelmy, G. Chincarini, D.N. Burrows, N. Gehrels, S. Covino et al., An origin for short [gamma]-ray bursts unassociated with current star formation, Naturefrom IGY_DC_McDonald-7.eps 9.15 collage 438:994-996, copyright 2005). and Saturn and they wanted to hear what Van Allen heliosheath, the subsonic region that is the outermost had to say. reach of the region in interstellar space carved out by Also shown in Figure 9.17 is data from the LECP the Sun. The heliosheath is probably 30–60 AU wide, experiment on Voyager 1, low-energy ion data that and at its current speed Voyager 2 could cross the he- shows that Voyager has crossed the termination shock liopause into the true interstellar medium in a decade of the solar wind, where the supersonic flow of the or so. solar wind goes subsonic to begin the process of merg- We live in times of unprecedented exploration. ing with the local interstellar medium. We have also Fifty years ago Van Allen and his co-workers began recently crossed the termination shock with Voyager the exploration of space with a simple experiment to 2, each Voyager spacecraft now penetrating into the understand the near-space environment of Earth. Since

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12 FORGING THE FUTURE OF SPACE SCIENCE Integrated Optical Telescope Element (OTE) Science Instrument Module (ISIM) Organization Mission Lead: Goddard Space Flight Center International collaboration with ESA & CSA Prime Contractor: Northrop Grumman Space Technology Cold, space-facing side Instruments: Sunshield – Near Infrared Camera (NIRCam) – Univ. of Arizona – Near Infrared Spectrograph (NIRSpec) – ESA – Mid-Infrared Instrument (MIRI) – JPL/ESA – Fine Guidance Sensor (FGS) – CSA Warm, Sun-facing side Operations: Space Telescope Science Institute Spacecraft Bus Description Deployable infrared telescope with 6.5 JWST Science Themes meter diameter segmented adjustable primary mirror Cryogenic temperature telescope and instruments for infrared performance Launch June 2013 on an ESA-supplied Ariane 5 rocket to Sun-Earth L2 End of the dark Birth of stars and Planetary 5-year science mission (10-year goal) The assembly of proto-planetary ages: First light systems and galaxies and reionization systems the origin of www.JWST.nasa.gov life FIGURE 9.16 Finding our origins with the James Webb Space Telescope (JWST) and the JWST Science Themes. Top: JWST (NASA). Bottom row, left to right: End of the dark agesfirst light and reionization (NASA/ESA/S. Beckwith(STScI)/HUDF Team). The assembly of galaxies (NASA). Birth of stars and proto-planetary systems (M.J. McCaughrean (Max-Planck-Institute for Astronomy), C.R. O’Dell 9.16 collage from IGY_DC_McDonald-8.eps (Rice University), and NASA). Planetary systems and the origin of life (NASA). then we have extended our presence to the farthest I would like to thank the Space Studies Board reaches of our solar system; we have explored all the again for the honor of being able to give the Van Allen planets; we have made detailed observations of our Sun Lecture. and the space environment it creates; we have observed the wonders of the universe.

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1 EXPLORER 1: GATEWAY TO THE NEVER ENDING WONDERS OF SPACE SCIENCE SOL AR APEX INTERSTELLAR Ions from shock fill the heliosheath WIND S Shock is source of low energy ions EARTH SU N SATURN URANUS PI ONEER 10 PI ONEER 11 NEPTUNE JUPITE R PLUTO FIGURE 9.17 Pioneer/Voyager. Top left: Saturn (NASA/JPL, PIA01969). Top right: Pioneer 10 news release image (NASA/ARC). Bottom left: Heliopause schematic (NASA). Bottom right: Termination shock; showing 5-day smoothed V1 40–53 ion (with kind per- mission from Springer Science+Business Media: J.D. IRichardson_McDonald-9.eps wind in the outer heliosphere, pp. 7-20 in 9.17 collage from GY_DC and E.C. Stone, The solar From the Outer Heliosphere to the Local Bubble, Springer New York, Copyright 2009, Figure 4a). ACKNOWLEDGMENTS lecture and paper, and also Joe Alexander for looking over her shoulder. Also, George Gloeckler and Randy Dr. McDonald acknowledges the assistance of Jokipii deserve special thanks for their help in prepar- V ictoria Swisher in assembling the figures for the ing the lecture.

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