251
Mariner 2 and the
64-meter capability for the mission. These historic early interplanetary mis- sions began a long collaboration between NASA and the CSIRO in space tracking, including the Apollo lunar landing missions, the Voyager 2 encoun- ters of Uranus and Neptune, the Galileo mission to Jupiter, the Huygens probe’s landing on Titan, and, most recently, the Curiosity rover on Mars.
This chapter will describe the beginnings of this international col- laboration and the special relationship that developed between the CSIRO and NASA.
THE BEGINNING
In the first decades of solar system exploration, the CSIRO’s Parkes Radio Telescope had its greatest influence on the design of antennas for NASA’s DSN. This influence was a result of close professional relationships estab- lished between major personalities at the CSIRO’s Radiophysics Laboratory and at the California Institute of Technology’s (Caltech) JPL, which operated as a NASA Field Center. To understand how Parkes came to have such an influence on the history of space tracking, it is necessary to go back to World War II, the development of radar, and the post-war foundation of radio astronomy in Australia. Major players at the CSIRO and JPL were dynamic and visionary individuals who laid some of the foundations for the modern era of space exploration.
RADAR AND THE ORIGINS OF THE CSIRO’S RADIOPHYSICS LABORATORY In early 1939, Richard Casey, Minister of Supply and Development for the Australian Commonwealth, learned of a highly secret scientific develop- ment from Britain known as radio direction finding (RDF), or radar, as it became known. With little information to go on, but shrewdly sensing that this might be a significant development, he immediately set in motion the process of founding a secret laboratory to investigate this development. It was given the innocuous title of the Radiophysics Laboratory to hide its true purpose. For security reasons, the Radiophysics Laboratory was built as an extension of the National Standards Laboratory, part of Australia’s Council for Scientific and Industrial Research (CSIR), the forerunner of the CSIRO.
Soon afterwards, following the British declaration of war, Richard Casey traveled to Britain and saw firsthand the coastal chain of radar stations that would make a significant contribution to winning the Battle of Britain.1
1. Sir Frederick White, “Richard Gardiner Casey 1890–1976,” Records of the Australian Academy of Science 3, no. 3/4 (1977), https://www.asap.unimelb.edu.au/bsparcs/aasmemoirs/
casey.htm (accessed 8 August 2021).
Later that year, with the war in Europe raging, Casey resigned from the Australian Parliament and traveled to Washington, DC, to open the first Australian diplomatic mission in a foreign country. He developed a close relationship with President Franklin D. Roosevelt, with leaders of the administration and with Congress. He thus founded a firm political rela- tionship between the United States and Australia, which proved invaluable in the dark days that followed as a Japanese invasion of Australia loomed.
In 1942, Casey accepted an invitation from British Prime Minister Winston Churchill to become Australia’s representative on his war cabinet.2
2. Ibid.
Richard Casey, Ambassador of Australia to the United States, in his office in Washington, DC, 1942.
(Library of Congress: fsa.8d22912)
Meanwhile, back in Australia, the Radiophysics Laboratory carried out research and developed radar equipment suitable for use in the Pacific the- ater. On the Sydney cliff tops at Dover Heights, overlooking the Pacific, the Royal Australian Air Force established a coastal defense radar station. The Radiophysics Laboratory used the site as a field station for its experimental radar work. During the war, radar operators reported strong radio emissions from the Sun. However, pressing wartime needs took precedence, and inves- tigations into the origin of these emissions had to wait until after the war.
The secret pre-war British development of radar had begun in 1935, when a Committee for the Scientific Study of Air Defence was established under the chairmanship of Henry Tizard. The “boffins,” as the members of the committee became known, were led by Robert Watson-Watt. They quickly set up experimental ground radar stations and, by 1936, were able to detect aircraft at ranges of up to 100 miles. One member of this team was a bril- liant, 24-year-old Welshman, Edward “Taffy” Bowen. In 1936, he was given the challenge of developing a radar unit small enough to fit in an aircraft for the principal application of night interception. By 1937, Bowen and his group had built an airborne radar system that could obtain clear echoes of ships off the English coast. Thereafter, their system became the standard for all airborne radar,3 which later proved to be a decisive factor in defeating the German U-boat threat in the Battle of the Atlantic.
In August 1940, with the Battle of Britain at a critical phase, Henry Tizard led a seven-member mission to the United States to disclose British technical advances in radar. Among them was Taffy Bowen, who brought with him not only information on all existing projected equipment but also an early sample of the cavity magnetron, the essential and highly secret key to the develop- ment of centimeter-wave radar. Following discussions with the Tizard mis- sion, the United States decided that its armed services would be responsible for radar development, with centimeter-wavelength development assigned to a special Microwave Committee chaired by Alfred Loomis. This com- mittee quickly set up a Radiation Laboratory at the Massachusetts Institute of Technology (MIT), with Lee DuBridge as director. Bowen collaborated closely with this lab and established a close rapport with DuBridge. This rela- tionship proved to be of pivotal significance in the years ahead, especially for space tracking applications. During the course of the war, the Radiation Lab grew in size and soon became the most important and productive radar laboratory in the United States. By the end of the war, lab staff numbered
3. Hanbury Brown, Harry Minnett, and Frederick White, “Edward George Bowen 1911–1991,”
Historical Records of Australian Science 9, no. 2 (December 1992): 151–166.
about 4,000.4 During this period, Bowen also befriended Vannevar Bush, President Roosevelt’s science advisor.
By 1943, with his work in the United States complete and the war in the Pacific swinging to the Allies’ favor, Bowen was invited to join Australia’s Radiophysics Laboratory in Sydney. In May 1946, he was appointed chief of the lab, a position he held for the next 25 years.5
THE DEVELOPMENT OF RADIO ASTRONOMY IN AUSTRALIA IN THE POST-WAR YEARS
At the end of the war, the radar labs in the United States and Britain were dis- banded, and their staff returned to their peacetime professions. In 1946, Lee DuBridge was appointed president of Caltech. Australia decided to keep its Radiophysics Lab intact and redirect its research into peaceful applications.
These applications included using radar to improve air navigation (impor- tant for a large country like Australia) and to study the physical processes of rain formation in clouds. Another project initiated at the time was the study of the origin of the radio emissions from the Sun that had so intrigued radar operators during the war.6
The radio astronomy group within the Radiophysics Lab was led by J. L.
“Joe” Pawsey.7 He pioneered the use of the “sea interferometer” (a radio ana- logue of a Lloyd’s mirror) to investigate the solar radio emissions. At the top of a cliff at Dover Heights, just south of the entrance to Sydney Harbour, Pawsey and his colleagues used surplus Yagi antennas to observe the Sun.
Radio emissions from the Sun reached the clifftop aerial along two paths, one direct and the other reflected by the sea surface. From the interference pattern so generated, it was possible to locate the source of the emission to
4. Ibid. Included among the battery of distinguished physicists at the MIT Rad Lab were Hans Bethe, R. H. Dicke, Robert V. Pound, E. M. Purcell, and J. H. van Vleck.
5. Ibid. In 1949, the Commonwealth Government enlarged and reconstituted the CSIR and its administrative structure. The new organization was named the CSIRO. Under Ian Clunies Ross as chairman, CSIRO pursued new research areas such as radio astronomy and indus- trial chemistry. The Radiophysics Laboratory was renamed the Division of Radiophysics.
6. Peter Robertson, “An Australian Icon—Planning and Construction of the Parkes Telescope,” Science with Parkes @ 50 Years Young Conference, Parkes, Australia, 31 October–4 November 2011. https://www.atnf.csiro.au/research/conferences/Parkes50th/
proceedings.html (accessed 8 August 2021).
7. Joe Pawsey’s group included names that would later become well known among the inter- national astronomical community, including Bernard Mills, Norman Christiansen, J. H.
Piddington, F. J. Kerr, Ronald N. Bracewell, and J. P. Wild.
an accuracy of a few arc-minutes.8 This measurement was accurate enough to identify sunspots as the source of much of the emissions.
Meanwhile, in 1946, British naval forces in the Pacific were demobi- lized, and a 24-year-old Royal Navy radar operator, John Bolton, decided to remain in Sydney rather than return home to Britain. After graduating from Trinity College at Cambridge in 1942, Bolton had joined the Royal Navy as a radar officer, but he was soon recruited into radar research at the then- secret Telecommunications Research Establishment (TRE)—Watson-Watt’s old group.9 By 1944, Bolton was serving on the aircraft carrier Unicorn in the Pacific. The day after his discharge from the Royal Navy, John Bolton met Taffy Bowen for an interview at the Radiophysics Laboratory. Bowen immediately took a liking to him and offered Bolton a position of technical research assistant. Bolton was set to work with Pawsey on the solar studies.
His attention, however, soon switched to identifying other, non-solar sources of radio emission.10
Within the next two years, Bolton, working with colleagues Gordon Stanley and Bruce Slee, conducted observations with the sea interferom- eter that resulted in the identification of four new cosmic radio sources—
Cygnus A, Taurus A, Centaurus A, and Virgo A. Initially, their radio positions were very poor, but by using larger, multi-element Yagi antennas, they were able to increase the sensitivity and resolution of their instruments.
By the early 1950s, over 100 sources of radio emission had been discovered at Dover Heights. They included supernova remnants and other sources in our own Milky Way galaxy and in very distant galaxies. These observations established the Radiophysics Laboratory as a world-leading center of radio astronomy and opened up the study of the universe at radio wavelengths.
In 1951, Bolton, Stanley, and Slee envisaged a more powerful instrument than the 12-element Yagi array they had been using. They began a project to build a 72-foot (22-meter)-diameter “hole-in-the-ground” antenna for a survey of the region near the galactic center of the Milky Way, which at the latitude of Sydney passes almost directly overhead. With considerable inge- nuity, they spent their lunchtimes, over a three-month period, excavating a dish-shaped hole in the sandy ground at Dover Heights. The surface was
8. J. P. Wild and V. R. Radhakrishnan, “John Gatenby Bolton 1922–1993,” Australian Academy of Science, https://www.science.org.au/fellowship/fellows/biographical-memoirs/john- gatenby-bolton-1922-1993 (accessed 8 August 2021).
9. Among other famous figures in radio astronomy who also worked at TRE were Hey, Hanbury-Brown, Bowen, Ryle, and Lovell.
10. Wild and Radhakrishnan.
consolidated with ash, and metal strips from packing cases were laid across the surface to provide reflectivity. A mast with a dipole was erected at the center of the antenna to receive the reflected radio signals. Remarkably, this instrument was the second-largest radio telescope in the world at the time.
By using the rotation of Earth and altering the position of the aerial mast, it was possible to observe different regions of the sky as they passed overhead.
After they had demonstrated that their design concept worked, the “hole- in-the-ground” antenna was extended to a diameter of 80 feet (24 meters) in 1953. This improved version led to detailed observations of Sagittarius A and the suggestion that it was the nucleus of our galaxy. In 1958, the International Astronomical Union ratified this view, making the position of the Sagittarius A radio source the Milky Way’s zero of longitude in a new system of galactic coordinates.11
By 1954, the technology at Dover Heights was becoming outdated, and the work that could be done with it was exhausted. Joe Pawsey decided to shut down the station. Radio astronomy, however, continued at the other Radiophysics field stations scattered across New South Wales, most notably in the field of solar studies led by Paul Wild.
THE GIANT RADIO TELESCOPE
In the early 1950s, Taffy Bowen had been thinking about the next phase in the development of radio astronomy. By 1954, with the closure of the Dover Heights field station complete, he was convinced that the best all-round instrument to continue the CSIRO’s pioneering efforts in radio astronomy would be a large, fully steerable dish antenna, or Giant Radio Telescope (GRT), in the 200- to 250-foot (61- to 76-meter) range. Bowen estimated that the cost of a GRT would be somewhere on the order of $1–2 million (USD).12 This investment was beyond the budget of the CSIRO at the time, so Bowen sought other sources of funding. It was then that Bowen’s war- time contacts came to the fore. Many of his colleagues during his radar days were in positions of authority and influence in the Australian government and in large philanthropic organizations in the United States. Bowen was
11. A. Blaauw, C. S. Gum, J. L. Pawsey, and G. Westerhout, “The New I. A. U. System of Galactic Coordinates (1958 revision),” Monthly Notices of the Royal Astronomical Society, vol. 121, p. 123, http://adsabs.harvard.edu/full/1960MNRAS.121..123B (accessed 29 January 2020).
12. Letter from Charles Dollard, president of the Carnegie Corporation, to E. G. Bowen, chief of the CSIRO Radiophysics Division, dated 14 April 1954.
determined to draw on this “old-boys network” to raise funds and make his vision a reality.13
FUNDING THE GRT
In August 1952, Bowen wrote to Vannevar Bush, then president of the Carnegie Institution for Science in Washington, DC, to ask if funds could be made available for his GRT.14 The early success of radio astronomy in Australia had attracted the attention of Bush and Alfred Loomis, who had become a trustee of the Carnegie Corporation, which supported the Carnegie Institution. Both knew Bowen through wartime friendships and admired his drive and enthusiasm.15 In due course, in May 1954, the Carnegie Corporation announced that it would provide $250,000 toward funding of the GRT in Australia.16
With funding from the Carnegie Corporation in hand, planning for the project could begin in earnest. In early 1955, the CSIRO set up a Radio Astronomy Trust with Richard Casey, who was by then Minister for External Affairs and Minister in Charge of the CSIRO, serving as its chairman.17 Casey was very sympathetic and made strong representations to Prime Minister Robert Menzies to support the project. Menzies agreed, provided that at least half of total costs would be raised from private sources.18
In 1955, Bowen again visited the United States, seeking support from other philanthropic organizations. He received a sympathetic hearing from the Rockefeller Foundation and its president, Dean Rusk. Two factors contrib- uted to this positive response: Richard Casey, chairman of Australia’s Radio Astronomy Trust, was well known to Dean Rusk from Casey’s time in war- time Washington, and Caltech president Lee DuBridge was a trustee of the Rockefeller Foundation and a great supporter of the GRT.19 The Rockefeller Foundation agreed to contribute $250,000.20
13. Robertson, “An Australian Icon,” p. 3.
14. Ibid.
15. White, “Richard Gardiner Casey.”
16. Letter from Charles Dollard, president of the Carnegie Corporation, to E. G. Bowen, chief of the CSIRO Radiophysics Division, dated 21 May 1954.
17. White, “Richard Gardiner Casey.”
18. Letter from Robert Menzies, the Australian Prime Minister, to Richard Casey, Minister for External Affairs and Minister in Charge of CSIRO, dated 19 April 1955.
19. White, “Richard Gardiner Casey.” Also see note 10.
20. Letter from the Rockefeller Foundation to Richard Casey, Minister for External Affairs and Minister in Charge of CSIRO, dated 8 December 1955.
Further funding of $107,000 was obtained from the Rockefeller Foundation in December 1959.21 A further grant of $100,000 from the Australian government was received in January 1960 to cover a shortfall in funds.22 When combined with $55,000 from private Australian donations and matching funds from the Australian government, funding for the GRT eventually came to $1.42 million.23
DESIGNING THE GRT
With initial funding secured from the Carnegie Corporation, work began on the GRT design in 1955. That year, a publicity booklet titled “A Proposal for a Giant Radio Telescope” was released, which was intended to stimulate the interest of engineers and contractors with many unusual design concepts presented.24 GRT designers were fortunate to learn from problems encoun- tered in the construction of the U.K.’s Jodrell Bank 250-foot (76-meter) dish, which had commenced in 1951.
The eventual breakthrough in final design came about by accident. During a trip to the U.K. in 1955, Taffy Bowen was introduced to Barnes Wallis, the famous chief engineer of the electrical engineering company Metropolitan- Vickers. Wallis was well known as the inventor of the “bouncing bombs”
of Dambusters fame during World War II. Over lunch one day, Bowen dis- cussed plans for the GRT with Wallis, who agreed to submit a few ideas. A few months later, Wallis submitted his plans, which included several inno- vative design features. One was the inclusion of spiral purlins to ensure the dish surface maintained a parabolic shape as it was tilted. The second feature was a master equatorial (ME), consisting of a small optical telescope situ- ated at the intersection of the two axes of rotation. The ME could be pointed to a particular direction in the sky with great accuracy. The dish would be
“slaved” to the ME via a servo loop, thus achieving a high degree of point- ing accuracy.25 Wallis also advocated an alt-azimuth mount with the dish pivoted in the center like an inverted umbrella.
21. Letter from the Rockefeller Foundation to Frederick White, Chairman of CSIRO, dated 8 December 1959.
22. Robertson, “An Australian Icon.” p. 7.
23. Frank Karr, “The Proposal for a Giant Radio Telescope,” in Parkes: Thirty Years of Radio Astronomy, ed. D. E. Goddard and D. K. Milne (Clayton, Australia: CSIRO Publishing, 1994), https://www.eoas.info/bib/ASBS00850.htm.
24. Ibid. P. Robertson, “An Australian icon: planning and construction of the Parkes telescope,”
Science with Parkes @ 50 Years Young, 31 October–4 November 2011, p. 11.
25. Robertson, “An Australian Icon,” p. 4.
The British firm Freeman Fox and Partners (FF&P) was engaged to per- form a detailed design study using Wallis’s ideas.26 Radiophysics engineer Harry Minnett was appointed his lab’s representative at FF&P to supervise the design and drive system. Both FF&P and Wallis favored an alt-azimuth mount because of its structural simplicity. An equatorial mount was stud- ied but rejected because an alt-azimuth mount could support a significantly larger dish. FF&P established the feasibility of the master equatorial and servo-drive system. Given the budget, a dish diameter of 210 feet (64 meters) was planned. Since the study had also shown that a minimum operating wavelength below 21 centimeters was feasible, a figure of 10 centimeters (S-band) was selected as the optimum operating wavelength for the 64-meter dish. To minimize spillover—detection of radiation from ground sources—
the telescope would have a 30-degree elevation horizon. The design study had taken three years to complete, much longer than originally planned.
However, the excellence of the design was recognized, vindicating the extra time it took to get it right.27
CHOOSING THE SITE
The site chosen for the GRT was near the town of Parkes in New South Wales, about 217 miles (350 kilometers) west of Sydney.28 Several require- ments were taken into consideration when choosing the site. The ideal loca- tion would need to be geologically stable to provide a solid foundation.
The site would need to have a mild climate free of ice and snow, with a low average wind speed year-round. It needed to be a few hours’ drive from the Radiophysics Lab’s headquarters in Sydney. Above all, the site had to offer a very low level of radio interference.29 During a comprehensive four-year search, several sites were considered and shortlisted. At a meeting convened at Radiophysics headquarters in March 1958 to decide the matter, Parkes was the unanimous choice.
26. The firm’s founder, Sir Ralph Freeman, Sr., was the designer of the Sydney Harbour Bridge, the most famous structure in Australia.
27. Harry Minnett, “The Construction of the Parkes 210-ft Radio Telescope,” in Parkes: Thirty Years of Radio Astronomy, ed. D. E. Goddard and D. K. Milne (Clayton, Australia: CSIRO Publishing, 1994).
28. B. Y. Mills, W. N. Christiansen, and J. P. Wild, “Report on the Site Requirements for the Giant Radio Telescope,” March 1958. Author’s files.
29. Robertson, “An Australian Icon,” p. 5.