For long-time space enthusiasts like myself, the US Army’s Redstone missile figures prominently in the early history of the Space Age (see “Redstone: The Missile That Launched America into Space”). In addition to serving as a battlefield weapon system deployed in Europe after being declared operational on June 1, 1958, the Redstone also served as the basis of the Jupiter-C/Juno I launch vehicle which launched America’s first satellite, Explorer 1, on January 31, 1958. Even after it was retired from its role as a satellite launch vehicle in favor of more capable rockets, in 1959 the Redstone was selected by NASA to launch the Mercury spacecraft on suborbital test flights. In this role it launched the first two Americans into space – Alan Shepard on May 5, 1961 and Virgil Grissom on July 21 (see “A History of Suborbital Crewed Spaceflights“).
After the Redstone was declared obsolete by the US Department of Defense and officially retired as a weapon system on October 30, 1964, “Old Reliable” (as the Redstone had become known) and its support equipment were subsequently given to museums or scrapped in the coming years (see “A Redstone in New Hampshire”). But before the Redstone was permanently consigned to history, it was used one last time to support a cooperative missile defense program involving the US, United Kingdom and Australia known as Project SPARTA (SPecial Antimissile Research Tests, Australia). The last of that program’s Redstones would subsequently be used for one final space mission to launch Australia’s first satellite.
The objective of Project SPARTA was to observe model warheads of various shapes and compositions during reentry using radar and a range of other ground-based sensors in support of the development of antimissile systems like the American Nike-Ajax. This new program was a follow on to the successful joint US/UK/Australia program known as Project Dazzle which launched subscale warheads from the Woomera Test Range in South Australia using the British Black Knight research rocket. While the original objectives of Dazzle and its predecessor, known as “Gaslight”, centered on developing a warhead design for the British Blue Streak medium range ballistic missile (which was cancelled as a weapon system in 1960), later tests were flown in part to support the development of anti-missile systems. By the time of the last Dazzle flight on November 25, 1965, plans were already in motion for Project SPARTA.
American support for SPARTA originated with the US Defense Department’s ARPA (Advanced Research Projects Agency) as part of its Project Defender antimissile research program. With management provided by the US Army Missile Command, the American contribution to SPARTA included providing the launch vehicles as well as their associated launch facilities and support teams. The Australian Weapons Research Establishment (WRE) was responsible for the Woomera range, operation of test equipment as well as the processing of some of the test data. The UK Ministry of Aviation continued its support because of its ongoing interest in studies started during Gaslight and Dazzle.
The prime contractor for SPARTA’s launch system was TRW Systems Group which oversaw the various subcontractors. In order to reduce costs and speed development so that launches could commence before the end of 1966, it was decided to use the now obsolete (and readily available) Redstone as the first stage in combination with two upper stages employing existing solid rocket motors and other systems. In August 1966 Chrysler, which had previously manufactured the Redstone after the initial development phase had been completed by Wernher von Braun and his team at ABMA (Army Ballistic Missile Agency), got the contract to refurbish and modify a total of ten production Redstones to serve as the first stage of the SPARTA launch vehicle as well as supply reentry vehicles for the tests. In order to support the SPARTA launches, some ground support equipment donated to the Smithsonian Institution had to be borrowed back. The subcontractor for the upper stages was LTV Aerospace Corporation. This pair of stages consisted of an Antares solid rocket motor (similar to that used in the third stage of NASA’s Scout all-solid launch vehicle) for the second stage and a BE-3 solid motor for the third stage. The Redstone-based SPARTA rocket stood about 20 meters tall with a launch mass of 30 metric tons – over twice the mass of the Black Knight research rocket.
During a typical SPARTA mission, the Redstone would lift off generating 334 kilonewtons of thrust burning a combination of ethanol and liquid oxygen. After a nominal 122-second burn, the forward instrument section of the rocket would separate and maintain the proper attitude for the ignition of the upper stages. Prior to ignition of the second stage, spin motors would fire to set the upper stages spinning at 150 rpm in order to provide stability. The Antares rocket motor would then ignite to raise the BE-3 third stage and its payload to an altitude of about 360 kilometers. After a delay, the third stage would then fire downwards to push the test body back into the atmosphere at speeds of over 6 kilometers per second – a higher velocity than was achievable earlier using the smaller Black Knight rocket employed in Gaslight and Dazzle. The reentry would then be observed using radar and ground based infrared and ultraviolet instruments.
The Australian Ministry of Supply (the parent organization of WRE) officially announced Project SPARTA in March 1966. In July, an American contractor team managed by TRW arrived in Australia to begin work with their WRE counterparts to construct the launch facilities in what became known as Launch Area 8 (LA-8). Work proceeded quickly with the goal of performing the first pair of SPARTA launches before the end of 1966 followed by launches on an approximately monthly basis thereafter.
The first SPARTA launch took place at 9:45 PM Australia Central Standard Time (ACST) on November 28, 1966. Unfortunately the flight was terminated due to “technical reasons” but the reentry of the rocket components was observed and provided some data. The second launch went off without a hitch at 9:20 PM ACST on December 13 with the flight apparently meeting all of its objectives. Project SPARTA was finally on its way.
The Birth of WRESAT
Anticipating that Project SPARTA would be able to meet all of its objectives with one rocket to spare, American officials informally approached WRE at the beginning of 1967 and offered to donate the surplus SPARTA rocket and launch services so that Australia could orbit its own satellite. The condition of the offer was that the launch would take place from Woomera shortly after the last SPARTA mission while American support personnel were still available. WRE immediately turned to the Department of Physics at the University of Adelaide with whom they had partnered for an ongoing research program on how phenomena in the upper atmosphere affected climate. The University of Adelaide already had experience with building and operating payloads for suborbital sounding rocket missions and had the expertise required to develop a satellite in the limited time allotted.
The primary objective of what became known as WRESAT (WRE SATellite) was to provide new data on how the Sun affected upper atmospheric physics to supplement the findings from their sounding rocket program. The secondary objectives included gaining experience in launching satellites from Woomera to support the ELDO’s (European Launch Development Organization) Europa and Britain’s Black Arrow satellite launch vehicle programs which were also using the Woomera Test Range.
In order to simplify the design of the satellite, it was decided that it would have a conical shape 1.59 meters long with a base diameter of 76 centimeters and a mass of 45 kilograms. The systems inside were thermally isolated from the exterior which used a special high temperature black paint to withstand aerodynamic heating during ascent as well as provide adequate thermal control once in orbit. To simplify the design of the satellite further, the BE-3 third stage remained attached to WRESAT once in orbit raising the total satellite mass to about 73 kilograms. This decision avoided the need to develop a separation system with its added mass and complexity while having no impact on the payload performance.
The instrument payload for WRESAT was based on the University of Adelaide’s previous work on sounding rocket payloads. The first instruments were a pair of packages each consisting of a trio of ionization chambers. Each package had an 80° field of view and were fitted with windows which allowed three different ultraviolet (UV) wavelength bands to be monitored in the 105 to 166 nanometer (nm) range with observations in the longer 156 to 166 nm band being made from a satellite for the first time. One set of ion chambers was mounted in the nose of the satellite while the second was pointed at a right angle on the side of the satellite. The tip of the satellite and a side panel would be ejected from the satellite once it reached orbit to provide the instruments with a clear view.
Also mounted in the nose of WRESAT was an ozone sensor which measured the intensity of sunlight passing through the atmosphere in the Hartley band at a UV wavelength of 250 nm. Also included in the instrument suite was an X-ray counter with a narrow spectral response centered on a wavelength of 0.8 nm (corresponding to an energy of 0.25 keV) to monitor solar activity. The side-mounted instrument suit also included a Lyman α telescope with a 2° field of view to detect hydrogen emissions at a wavelength of 121.6 nm from the Earth’s hydrogen geocorona as well as reflections from Earth.
When WRESAT first entered orbit, it would share the 150 rpm spin of the upper stages of its launch vehicle. In order to allow the nose-mounted instruments to scan the celestial sphere, WRESAT was fitted with energy dissipating “wobblers” which would within an orbit or two alter the spin axis from the long axis of the conical-shaped satellite to a dynamically more stable flat spin with a rate of about 30 rpm. The spin axis would be perpendicular to the rays of the Sun allowing the nose-mounted instruments to make measurements of the Sun once every revolution. Solar aspect sensors mounted in the nose and with the side-looking instruments in combination with a magnetometer allowed the attitude of the spinning satellite to be determined to aid in the analysis of the instrument data. NASA would provide tracking services for the battery-powered satellite which was expected to have a lifetime of up to ten days.
The WRESAT instruments were designed to support the mission’s three scientific experiments. The first was the orbital sunrise-sunset experiment which would use the nose-mounted, UV-sensitive ion chambers and ozone sensor to observe sunlight passing through the atmosphere in order to calculate profiles of how oxygen and ozone concentrations change with altitude. The orbital daylight experiment would use the ion chambers and the X-ray sensors to monitor the solar flux at these wavelengths with the Lyman α telescope measuring the Earth’s albedo at the anti-solar point at this UV wavelength. The primary instrument for the orbital nighttime experiment would be the Lyman α telescope which would be used to measure the brightness of the Earth’s hydrogen geocorona and locate the positions of UV-bright astronomical sources.
WRE worked closely with TRW to modify the SPARTA launch vehicle for the WRESAT mission which would use refurbished components of the Chrysler-built Redstone rounds CC-2029 and CC-2018. The launch vehicle’s guidance program had to be modified not only to place the satellite in orbit but drop the spent Redstone first stage inside of the existing proclaimed area of the Simpson Desert and the second stage off of the northern coast of Australia in the Gulf of Carpentaria. The ascent trajectory also had to contend with limiting the aerodynamic heating of the second stage even after its thermal protection was modified.
In its satellite launch vehicle role, the Redstone first stage of the SPARTA rocket would burn for its nominal 122 seconds to place the upper stages and WRESAT on a trajectory with an apogee of about 185 kilometers. After setting the upper stages spinning, the second and third stages would ignite in succession upon reaching apogee placing WRESAT (and the spent third stage of its launch vehicle) into a 185 by 1,300 kilometer near-polar orbit with an expected lifetime of 40 days. Range safety considerations limited the launch azimuth to 6° east of north with the satellite inserted into orbit at a latitude of 27° south. The proper choice of the launch time would place WRESAT into orbit with its spin axis oriented at right angles to the Sun so that its instruments could execute their observations as intended.
Despite the tight development schedule, WRE and the University of Adelaide managed to construct three satellites in the allotted 11-month time period: two engineering models for ground testing and a flight model for launch. And with the successful launch of the final mission for Project SPARTA on October 31, 1967, the way was clear to launch WRESAT by mid-December. After a last minute glitch with WRESAT’s electronics three days before the satellite was to be integrated with the SPARTA rocket, everything was set for launch.
After the first launch attempt was scrubbed on November 28, 1967 at the T-30 second mark, the tenth SPARTA rocket carrying WRESAT lifted off from LA-8 at Woomera at 2:19 PM ACST (04:49 GMT) on November 29. The first tracking pass over the American tracking facility at Guam confirmed that all three stages of the rocket performed as expected to place WRESAT into a 193 by 1,259 kilometer orbit with an inclination of 83.2°. Australia had become the fourth nation to orbit a satellite launched from its own territory after the Soviet Union (Sputnik from what would become the Baikonur Cosomdrome in Soviet Kazakhstan in October 1957 – see “Sputnik: The Launch of the Space Age”), the United States (Explorer 1 from Cape Canaveral, Florida in January 1958) and France (Astérix in November 1965 from Hammaguir, Algeria which had formerly been under French rule – a bit of a stretch for a definition of a nation’s “own territory”). This was the last launch of the Redstone which not only had launched the US into space but now Australia as well.
WRESAT’s instruments returned data for five days with its batteries being depleted after 73 orbits of the Earth. Data from the UV instrumentation, confirmed by observations from other satellites like SOLRAD 10B, indicated that the Sun had an effective temperature of 4,570±50 K during this period of minimum solar activity. The orbit of the now-silent WRESAT decayed over the North Atlantic Ocean off the coast of Ireland at 11:34 GMT on January 10, 1968. It had orbited the Earth a total of 642 times over the course of 42 days.
While WRESAT was a resounding success, unfortunately the Australian government was not interested in expanding the role of its nascent space program. Even after half a century, WRESAT remains the only Australian satellite launched from Australian territory. In an interesting postscript to this almost forgotten mission, the remains of WRESAT’s Redstone first stage were recovered from Australia’s Simpson Desert in April 1990 and subsequently put on display at the Woomera National Aerospace and Missile Park where it lies in silent testimony to this historic accomplishment.
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Here is an excerpt from a documentary film showing the preparations for the launch of WRESAT.
“Redstone: The Missile That Launched America into Space”, Drew Ex Machina, April 26, 2016 [Post]
“America’s First Satellite… Almost”, Drew Ex Machina, October 4, 2015 [Post]
“A Redstone in New Hampshire”, Drew Ex Machina, October 30, 2015 [Post]
J.H. Carver et al., “Ultraviolet Ion Chamber Measurements of the Solar Minimum Brightness Temperature”, Solar Physics, Vol. 27, No. 2, pp 347-353, December 1972
Keith J. Scala and Michael A. Crowe, “SPARTA Program: The Redstone Down Under”, Spaceflight, Vol. 33, No. 8, pp 287–288, August 1991
“Redstones for Woomera”, Flight International, p 1128, December 30, 1965
“Anti-Missile Tests Begin at Woomera”, Flight International, pp 145 & 150, January 26, 1967
WRESAT – Weapons Research Establishment SATellite, Department of Supply (Australia), November 1967