SOLRAD (SOLar RADiation) 2 was the public designation for a combination surveillance and solar X-rays and ultraviolet scientific satellite, the second in the SOLRAD program developed by the United States Navy's Naval Research Laboratory. The SOLRAD scientific package aboard the satellite provided cover for the GRAB (Galactic Radiation and Background) electronic surveillance package, the mission of which was to map the Soviet Union's air defense radar network.
SOLRAD 2 was launched along with Transit 3A atop a Thor-Ablestar rocket on 30 November 1960, but both satellites failed to reach orbit when the booster flew off course and was destroyed, raining debris over Cuba, which prompted official protests from the Cuban government. As a result, future SOLRAD flights were programmed to avoid a Cuban flyover during launch.
Background
SOLRAD 1 on top of Transit 2A with four of its creators. From left: Martin J. Votaw, George G. Kronmiller, Alfred R. Conover, and Roy A. Harding.
In 1957, the Soviet Union began deploying the S-75 Dvinasurface-to-air missile, controlled by Fan Song fire control radars. This development made penetration of Soviet air space by American bombers more dangerous. The U.S. Air Force began a program of cataloging the rough location and individual operating frequencies of these radars, using electronic reconnaissance aircraft flying off the borders of the Soviet Union. This program provided information on radars on the periphery of the Soviet Union, but information on the sites further inland was lacking. Some experiments were carried out using radio telescopes looking for serendipitous Soviet radar reflections off the Moon, but this proved an inadequate solution to the problem.[2]:362
In March 1958,[3]:4 while the Naval Research Laboratory (NRL) was heavily involved in Project Vanguard, the U.S. Navy's effort to launch a satellite, NRL engineer Reid D. Mayo, determined that a Vanguard derivative could be used to map Soviet missile sites. Mayo had previously developed a system for submarines whereby they could evade anti-submarine aircraft by picking up their radar signals. Physically small and mechanically robust, it could be adapted to fit inside the small Vanguard frame.[2]:364
Mayo presented the idea to Howard Lorenzen, head of the NRL's countermeasures branch. Lorenzen promoted the idea within the U.S. Department of Defense (DoD), and six months later the concept was approved under the name "Tattletale".[2]:364President Eisenhower approved full development of the program on 24 August 1959.[3]:4
After a news leak by The New York Times, Eisenhower cancelled the project. The project was restarted under the name "Walnut" (the satellite component given the name "DYNO".[1]:140,151) after heightened security had been implemented, including greater oversight and restriction of access to "need-to-know" personnel.[4]:2 American space launches were not classified at the time,[5][6] and a co-flying cover mission that would share space with DYNO was desired to conceal DYNO's electronic surveillance mission from its intended targets.[7]:300
The study of the Sun's electromagnetic spectrum provided an ideal cover opportunity. The U.S. Navy had wanted to determine the role of solar flares in radio communications disruptions [7]:300 and the level of hazard to satellites and astronauts posed by ultraviolet and X-ray radiation.[8]:76 Such a study had not previously been possible as the Earth's atmosphere blocks the Sun's X-ray and ultraviolet output from ground observation. Moreover, solar output is unpredictable and fluctuates rapidly, making sub-orbital sounding rockets inadequate for the observation task. A satellite was required for long-term, continuous study of the complete solar spectrum.[9]:5–6,63–65[10]
Wavelengths of light blocked by Earth's atmosphere
The NRL already had a purpose-built solar observatory in the form of Vanguard 3, which had been launched in 1959. Vanguard 3 had carried X-ray and ultraviolet detectors, though they had been completely saturated by the background radiation of the Van Allen belts.[9]:63 Development of the DYNO satellite from the Vanguard design was managed by NRL engineer Martin Votaw, leading a team of Project Vanguard engineers and scientists who had not migrated to NASA.[11] The dual-purpose satellite was renamed GRAB ("Galactic Radiation And Background"), sometimes referred to as GREB ("Galactic Radiation Experiment Background"), and referred to in its scientific capacity as SOLRAD ("SOLar RADiation").[1]:142,149[7]:300
A dummy mass simulator SOLRAD was successfully launched on 13 April 1960, attached to a Transit 1B,[7]:301 proving the dual satellite launch technique.[12] On 5 May 1960, just four days after the downing of Gary Powers'U-2 flight over the Soviet Union highlighted the vulnerability of aircraft-based surveillance, President Eisenhower approved the launch of an operational SOLRAD satellite.[13]:32SOLRAD/GRAB 1 was launched into orbit on 22 June 1960, becoming both the world's first surveillance satellite and the first satellite to observe the Sun in X-ray and ultraviolet light.[7]
Spacecraft
SOLRAD 1, its principal external features labeled.
SOLRAD 2 was roughly a duplicate of its predecessor, SOLRAD/GRAB 1,[14] spherical and 51cm (20in) in diameter,[8] slightly lighter than SOLRAD/GRAB 1 despite carrying the same scientific experiments (18kg (40lb) versus 19.05kg (42.0lb)),[4] and powered by six circular patches of solar cells.[4]:a1-4 The solar cells powered nine D cell batteries in series (12 volts total) [4]:10 providing 6 watts of power.[13]:32
The satellite's SOLRAD scientific package included two Lyman-alphaphotometers (nitric oxide ion chambers) for the study of ultraviolet light in the 1,050–1,350 Å wavelength range and one X-ray photometer (an argon ion chamber) in the 2–8 Å wavelength range, all mounted around the equator of the satellite.[15] As with SOLRAD 1, permanent magnets were installed to deflect charged particles from the detector windows to address the saturation issue that had impacted the Vanguard 3 mission.[9]:64–65
The satellite's GRAB surveillance equipment was designed to detect Soviet air defense radars broadcasting on the S-band (1,550–3,900 MHz),[13]:29,32 over a circular area 6,500km (4,000mi) in diameter beneath it.[1]:108 A receiver in the satellite was tuned to the approximate frequency of the radars, and its output was used to trigger a separate Very high frequency (VHF) transmitter in the spacecraft. As it traveled over the Soviet Union, the satellite would detect the pulses from the missile radars and immediately re-broadcast them to American ground stations within range, which would record the signals and send them to the NRL for analysis. Although GRAB's receiver was omnidirectional, by looking for the same signals on multiple passes and comparing that to the known location of the satellite, the rough location of the radars could be determined, along with their exact pulse repetition frequency.[3]:4–7[1]:108
"NSA Data Reduction", indicating the intelligence to be derived by processing the satellite downlink
Like most early automatic spacecraft, SOLRAD 2, though spin stabilized,[7]:300 lacked active attitude control systems and thus scanned the whole sky without focusing on a particular source.[9]:13 So that scientists could properly interpret the source of the X-rays detected by SOLRAD 2, the spacecraft carried a vacuum photocell to determine when the Sun was striking its photometers and the angle at which sunlight hit them.[9]:64
In November 1960, Votaw and his 14-man team drove the technical components for the SOLRAD 2 launch (loaded in the trunks of their own cars) from NRL headquarters in Washington, D.C. to Cape Canaveral, flying having been ruled out due to the recent rash of skyjackings to Cuba. Upon arrival, the NRL team set up a temporary ground station in a hangar on the Cape's west side. SOLRAD 2's booster (first stage Thor No. 283 and second stage Able-Star 006) was erected nearly three miles away at Cape Canaveral Pad LC-17B.[18]
On launch day, 30 November 1960, minor glitches caused so many holds in the hours-long countdown that the NRL team commissioned a betting pool as to when the launch would occur.[18] Nevertheless, SOLRAD 2 did launch, along with Transit 3A (a separate satellite on the same rocket), at 19:50 GMT,[12] into a sunny sky. The Thor first stage shut down prematurely (it had been scheduled to burn for 163 seconds). Out of caution, despite the possibility that its payload could still be orbited, the now separated first and second stages of the booster were destroyed by the range safety officer.[18]
Like SOLRAD 1 (but no other American launches to date), SOLRAD 2's course to orbit took it over the Caribbean island of Cuba.[19] As a result of the rocket's destruction, fragments fell over Cuba's Oriente Province at the eastern end of the island, northwest of the U.S. Navy's Guantanamo Bay base. The Cuban Army post at Holguín reported fragments falling along a 200sqmi (518km2) swath and reported recovering "two complete sphere [sic], two apparatuses in the form of cones and various cylinders" with English inscriptions. One piece of recovered debris was described as a "sealed sphere of some 40 pounds". Given that Vanguard TV-3's satellite survived a booster explosion, it is possible that this was SOLRAD 2, recovered intact. The items were then delivered to army headquarters at Palma Soriano. According to a 1988 Chinese document, some of the recovered debris was sold to the People's Republic of China and used in aid of the design of the second stage of the CSS-4intercontinental ballistic missile (ICBM).[18]
The Cuban government protested the incident: Revolución, an official Cuban newspaper, accused the United States of "Yankee provocation", and government radio stations denounced what they described as efforts to destroy Castro's regime. Cuba lodged an official complaint with the United Nations. In response to these protests, American launches overflying Cuba were postponed, improvements were made to the range-safety system at Cape Canaveral,[18] and future SOLRAD flights were programmed to follow a more northerly course to orbit during launch that did not overfly Cuba.[20]
Legacy
The SOLRAD/GRAB series flew three more times finishing with the SOLRAD 4B mission launched 26 April 1962. Of the five SOLRAD/GRAB missions, only SOLRAD/GRAB 1 and SOLRAD 3/GRAB 2 were successes, the others failing to reach orbit. In 1962, all U.S. overhead reconnaissance projects were consolidated under the National Reconnaissance Office (NRO), which elected to continue and expand the GRAB mission starting July 1962 [1] with a next-generation set of satellites, code-named POPPY.[4] With the initiation of POPPY, SOLRAD experiments would no longer be carried on electronic spy satellites; rather, they would now get their own satellites, launched alongside POPPY missions to provide some measure of mission cover.[12] Starting with SOLRAD 8, launched in November 1965, the final five SOLRAD satellites were scientific satellites launched singly, three of which were also given NASA Explorer program numbers. The last in this final series of SOLRAD satellites flew in 1976. In all, there were thirteen operational satellites in the SOLRAD series.[7] The GRAB program was declassified in 1998.[20]
A reconnaissance satellite or intelligence satellite is an Earth observation satellite or communications satellite deployed for military or intelligence applications.
Vanguard 1 is an American satellite that was the fourth artificial Earth-orbiting satellite to be successfully launched, following Sputnik 1, Sputnik 2, and Explorer 1. It was launched 17 March 1958. Vanguard 1 was the first satellite to have solar electric power. Although communications with the satellite were lost in 1964, it remains the oldest human-made object still in orbit, together with the upper stage of its launch vehicle.
Project Vanguard was a program managed by the United States Navy Naval Research Laboratory (NRL), which intended to launch the first artificial satellite into low Earth orbit using a Vanguard rocket. as the launch vehicle from Cape Canaveral Missile Annex, Florida.
Vanguard 3 is a scientific satellite that was launched into Earth orbit by the Vanguard SLV-7 on 18 September 1959, the third successful Vanguard launch out of eleven attempts. Vanguard rocket: Vanguard Satellite Launch Vehicle-7 (SLV-7) was an unused Vanguard TV-4BU rocket, updated to the final production Satellite Launch Vehicle (SLV).
The Solar Radiation and Climate Experiment (SORCE) was a NASA-sponsored satellite mission that measured incoming X-ray, ultraviolet, visible, near-infrared, and total solar radiation. These measurements specifically addressed long-term climate change, natural variability, atmospheric ozone, and UV-B radiation, enhancing climate prediction. These measurements are critical to studies of the Sun, its effect on the Earth's system, and its influence on humankind. SORCE was launched on 25 January 2003 on a Pegasus XL launch vehicle to provide NASA's Earth Science Enterprise (ESE) with precise measurements of solar radiation.
Galactic Radiation and Background (GRAB) was the first successful United States orbital surveillance program, comprising a series of five Naval Research Laboratory electronic surveillance and solar astronomy satellites, launched from 1960 to 1962. Though only two of the five satellites made it into orbit, they returned a wealth of information on Soviet air defense radar capabilities as well as useful astronomical observations of the Sun.
POPPY is the code name given to a series of U.S. intelligence satellites operated by the National Reconnaissance Office. The POPPY satellites recorded electronic signals intelligence (ELINT) data, targeting radar installations in the Soviet Union and Soviet naval ships at sea.
Thor was a US space launch vehicle derived from the PGM-17 Thor intermediate-range ballistic missile. The Thor rocket was the first member of the Delta rocket family of space launch vehicles. The last launch of a direct derivative of the Thor missile occurred in 2018 as the first stage of the final Delta II.
SOLRAD was an American series of satellites sponsored by the US Navy in a program to continuously monitor the Sun. SOLRAD was the Naval Research Laboratory's first post-Vanguard satellite.
SOLRAD 4B was a solar X-ray, ultraviolet, and electronic surveillance satellite. Developed by the United States Navy's United States Naval Research Laboratory, it was the fifth in both the SOLRAD and the GRAB programs.
The SOLRAD 8,Explorer 30 or SE-A satellite was one of the NASA SOLRAD program that began in 1960 to provide continuous coverage of solar radiation with a set of standard photometers. SOLRAD 8 was a spin-stabilized satellite oriented with its spin axis perpendicular to the sun-satellite line so that the 14 solar X-ray and ultraviolet photometers pointing radially outward from its equatorial belt viewed the sun on each revolution. Data were transmitted in real time by means of an FM / AM the satellite's telemetry system and were recorded by the stations on the Spacecraft Tracking and Data Acquisition Network (STADAN) tracking network.
Vanguard TV-5, also called Vanguard Test Vehicle-Five, was a failed flight of the American Vanguard rocket following the successful launch of Vanguard 1 on Vanguard TV-4. Vanguard TV-5 launched on 29 April 1958 at 02:53:00 GMT, from Launch Complex 18A at the Cape Canaveral Air Force Station. The rocket was unsuccessful in its attempt to place an unnamed satellite into orbit.
Solrad 10, also known Explorer 44, NRL-PL 165 and Explorer SE-C, was one of the SOLRAD series designed to provide continuous coverage of wavelength and intensity changes in solar radiation in the UV, soft and hard X-ray regions. The satellite also mapped the celestial sphere using a high-sensitivity X-ray detector. Information collected was expected to contribute to a better understanding of the physical processes involved in solar flares and other solar activity, and the potential effects of this activity on short-wave communications, as well as on future human space travel. For the period of July 1971 to June 1973, the core memory data of Explorer 44 were used rather than those from Explorer 37. The Explorer 44 core memory failed on 11 June 1973, and Explorer 37 was heavily used until 25 February 1974, when the gas supply of the attitude control system was exhausted.
The Gravity Gradient Stabilization Experiment (GGSE-1) was a technology satellite launched simultaneously with four other satellites on 11 January 1964 by the U.S. military from Vandenberg Air Force Base aboard a Thor Augmented Delta-Agena D rocket. It demonstrated a new oscillation damping system intended for use in reconnaissance satellites.
SOLRAD 7A was the seventh solar X-Ray monitoring satellite in the SOLRAD series, and the fourth to successfully orbit the Earth. It was boosted into orbit along with four other military satellites atop a Thor Augmented Delta-Agena D rocket on January 11, 1964. Data returned by SOLRAD 7A dramatically revised scientific models of the solar corona.
SOLRAD1 is the public designation for SOLRAD/GRAB 1, a combination science and surveillance satellite launched into orbit on 22 June 1960. It was the first satellite to successfully observe solar X-rays, the first to conduct surveillance from orbit, and the first to be launched with another instrumented satellite.
SOLRAD 3 was a solar X-ray satellite, the third in the SOLRAD program. Developed by the United States Navy's Naval Research Laboratory (USNRL), it shared satellite space with and provided cover for the Navy's GRAB 2, a secret electronic surveillance program.
SOLRAD 6 was the sixth solar X-ray monitoring satellite in the United States Navy's SOLRAD series, the third in the series to successfully orbit. It was launched along with POPPY 2, an ELINT surveillance package, as well as three other satellites, boosted into orbit via a Thor Augmented Delta-Agena D rocket on June 15, 1963.
SOLRAD 4 was a solar X-rays, ultraviolet, and electronic surveillance satellite. Developed by the United States Navy's United States Naval Research Laboratory (USNRL), it was the fourth in both the SOLRAD and the GRAB programs.
SOLRAD 7B was the eighth solar X-Ray monitoring satellite in the SOLRAD series and the fifth to successfully orbit the Earth. It was launched via Thor Augmented Delta-Agena D along with seven other satellites on March 9, 1965. The satellite provided continuous coverage of the Sun during the International Quiet Solar Year from March through October 1965.
1 2 3 4 5 Significant Achievements in Solar Physics 1958–1964. NASA. 1966. OCLC860060668. This article incorporates text from this source, which is in the public domain.
↑ Committee on the Navy's Needs in Space for Providing Future Capabilities, Naval Studies Board, Division on Engineering and Physical Sciences, National Research Council of the National Academies (2005). "Appendix A: Department of the Navy History in Space". Navy's Needs in Space for Providing Future Capabilities. The National Academies Press. p.157. doi:10.17226/11299. ISBN978-0-309-18120-4. Archived from the original on 7 January 2019. Retrieved 6 January 2019.{{cite book}}: CS1 maint: multiple names: authors list (link)
↑ "SOLRAD 1". NASA. 14 May 2020. Retrieved 15 January 2021. This article incorporates text from this source, which is in the public domain.
↑ Green, Constance and Lomask, Milton (1970). Vanguard – A History. NASA. ISBN978-1-97353-209-5. SP-4202. Archived from the original on 3 March 2016. Retrieved 28 April 2019.{{cite book}}: CS1 maint: multiple names: authors list (link) This article incorporates text from this source, which is in the public domain.
Payloads are separated by bullets (·), launches by pipes ( | ). Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in brackets.
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