SOLRAD (SOLar RADiation) 2 was the public designation for a combination surveillance and solar X-rays and

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...

scientific satellite, the second in the

SOLRAD SOLRAD (short for "SOLar RADiation," sometimes presented as "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 satelli ...

program developed by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

Naval Research Laboratory The United States Naval Research Laboratory (NRL) is the corporate research laboratory for the United States Navy and the United States Marine Corps. It was founded in 1923 and conducts basic scientific research, applied research, technological ...

. The SOLRAD scientific package aboard the satellite provided cover for the GRAB (Galactic Radiation and Background)

electronic surveillance Surveillance is the monitoring of behavior, many activities, or information for the purpose of information gathering, influencing, managing or directing. This can include observation from a distance by means of electronic equipment, such as c ...

package, the mission of which was to map the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

's air defense radar network. SOLRAD 2 was launched along with Transit 3A atop a

Thor-Ablestar The Thor-Ablestar, or Thor-Able-Star, also known as Thor-Epsilon was an early American expendable launch system consisting of a PGM-17 Thor missile, with an Ablestar upper stage. It was a member of the Thor family of rockets, and was derived fro ...

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 Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...

, which prompted official protests from the Cuban government. As a result, future SOLRAD flights were programmed to avoid a Cuban flyover during launch.

Background

In 1957, the

began deploying the

S-75 Dvina The S-75 (Russian: С-75; NATO reporting name SA-2 Guideline) is a Soviet-designed, high-altitude air defence system, built around a surface-to-air missile with command guidance. Following its first deployment in 1957 it became one of the most w ...

surface-to-air missile A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground to destroy aircraft or other missiles. It is one type of anti-aircraft syst ...

, controlled by

Fan Song The Fan Song is the NATO reporting name for SNR-75 series of trailer-mounted E band/ F band and G band fire control and tracking radars for use with the Soviet SA-2 Guideline surface-to-air missile system. Description The Fan Song radars ar ...

fire control radars. This development made penetration of Soviet air space by American bombers more dangerous. The

U.S. Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Sign ...

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 The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, but this proved an inadequate solution to the problem. In March 1958, while the

(NRL) was heavily involved in

Project Vanguard 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 ...

, the

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...

'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. 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 The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national secur ...

(DoD), and six months later the concept was approved under the name "Tattletale".

President Eisenhower Dwight David "Ike" Eisenhower (born David Dwight Eisenhower; ; October 14, 1890 – March 28, 1969) was an American military officer and statesman who served as the 34th president of the United States from 1953 to 1961. During World War II, ...

approved full development of the program on 24 August 1959. After a news leak by ''

The New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...

'', Eisenhower cancelled the project. The project was restarted under the name "Walnut" (the satellite component given the name "DYNO". ) after heightened security had been implemented, including greater oversight and restriction of access to "

need-to-know The term "need to know", when used by government and other organizations (particularly those related to the military or espionage), describes the restriction of data which is considered very sensitive. Under need-to-know restrictions, even if one ...

" personnel. American space launches were not classified at the time, 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. The study of the Sun's

electromagnetic spectrum The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from ...

provided an ideal cover opportunity. The U.S. Navy had wanted to determine the role of solar flares in radio communications disruptions and the level of hazard to satellites and astronauts posed by ultraviolet and X-ray radiation. 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 A sounding rocket or rocketsonde, sometimes called a research rocket or a suborbital rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The rockets are used to ...

inadequate for the observation task. A satellite was required for long-term, continuous study of the complete solar spectrum. Atmospheric electromagnetic opacity

The NRL already had a purpose-built solar observatory in the form of

Vanguard 3 Vanguard 3 (Harvard designation: 1959 Eta 1) 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 Satell ...

, 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. 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 The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

. 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"). A dummy

mass simulator A boilerplate spacecraft, also known as a mass simulator, is a nonfunctional craft or payload that is used to test various configurations and basic size, load, and handling characteristics of rocket launch vehicles. It is far less expensive t ...

SOLRAD was successfully launched on 13 April 1960, attached to a Transit 1B, proving the dual satellite launch technique. On 5 May 1960, just four days after the downing of Gary Powers' U-2 flight over the

highlighted the vulnerability of aircraft-based surveillance, President Eisenhower approved the launch of an operational SOLRAD satellite. SOLRAD/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.

Spacecraft

SOLRAD 2 was roughly a duplicate of its predecessor, SOLRAD/GRAB 1, spherical and in diameter, slightly lighter than SOLRAD/GRAB 1 despite carrying the same scientific experiments ( versus ), and powered by six circular patches of

solar cells A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physics, physical and Chemical substance, chemical phenomenon. The solar cells powered nine D cell batteries in series (12

volt The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Defi ...

s total) providing 6

watt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wa ...

s of power. The satellite's SOLRAD scientific package included two

Lyman-alpha The Lyman-alpha line, typically denoted by Ly-α, is a spectral line of hydrogen (or, more generally, of any one-electron atom) in the Lyman series. It is emitted when the atomic electron transitions from an ''n'' = 2 orbital to the gr ...

photometer A photometer is an instrument that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared and including the visible spectrum. Most photometers convert light into an electric current using a photoresistor, ph ...

s (nitric oxide

ion chamber The ionization chamber is the simplest type of gas-filled radiation detector, and is widely used for the detection and measurement of certain types of ionizing radiation, including X-rays, gamma rays, and beta particles. Conventionally, the term ...

s) for the study of ultraviolet light in the 1,050–1,350 Å wavelength range and one X-ray photometer (an

argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...

ion chamber) in the 2–8 Å wavelength range, all mounted around the equator of the satellite. 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

mission. The satellite's GRAB surveillance equipment was designed to detect Soviet air defense radars broadcasting on the

S-band The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventional ...

(1,550–3,900

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...

), over a circular area in diameter beneath it. 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 Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves ( radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF ...

(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 The pulse repetition frequency (PRF) is the number of pulses of a repeating signal in a specific time unit. The term is used within a number of technical disciplines, notably radar. In radar, a radio signal of a particular carrier frequency is tu ...

Telemetry Telemetry is the in situ data collection, collection of measurements or other data at remote points and their automatic data transmission, transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Gr ...

was sent via four whip-style long antennas mounted on SOLRAD's equator. Scientific telemetry was sent on 108 MHz, the

International Geophysical Year The International Geophysical Year (IGY; french: Année géophysique internationale) was an international scientific project that lasted from 1 July 1957 to 31 December 1958. It marked the end of a long period during the Cold War when scientific ...

standard frequency used by Vanguard. Commands from the ground and electronic surveillance were collected via smaller antennas on 139 MHz. Data received on the ground was recorded on magnetic tape and couriered back to the NRL, where it was evaluated, duplicated, and forwarded to the

National Security Agency The National Security Agency (NSA) is a national-level intelligence agency of the United States Department of Defense, under the authority of the Director of National Intelligence (DNI). The NSA is responsible for global monitoring, collecti ...

(NSA) at Army Fort Meade,

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

, and the

Strategic Air Command Strategic Air Command (SAC) was both a United States Department of Defense Specified Command and a United States Air Force (USAF) Major Command responsible for command and control of the strategic bomber and intercontinental ballistic missile ...

(SAC) at

Offut Air Force Base Offutt Air Force Base is a U.S. Air Force base south of Omaha, adjacent to Bellevue in Sarpy County, Nebraska. It is the headquarters of the U.S. Strategic Command (USSTRATCOM), the 557th Weather Wing, and the 55th Wing (55 WG) of the Air Co ...

Omaha Omaha ( ) is the largest city in the U.S. state of Nebraska and the county seat of Douglas County. Omaha is in the Midwestern United States on the Missouri River, about north of the mouth of the Platte River. The nation's 39th-largest city ...

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the southwe ...

, for analysis and processing. Like most early automatic spacecraft, SOLRAD 2, though spin stabilized, lacked active

attitude control Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc. Controlling vehicle ...

systems and thus scanned the whole sky without focusing on a particular source. 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.

Mission

Thor_Able_Star_with_Transit_3A_Nov_30_1960_pad

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. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

Cape Canaveral , image = cape canaveral.jpg , image_size = 300 , caption = View of Cape Canaveral from space in 1991 , map = Florida#USA , map_width = 300 , type =Cape , map_caption = Location in Florida , location ...

, flying having been ruled out due to the recent rash of skyjackings to

. 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 Thor (; from non, Þórr ) is a prominent god in Germanic paganism. In Norse mythology, he is a hammer-wielding æsir, god associated with lightning, thunder, storms, sacred trees and groves in Germanic paganism and mythology, sacred groves ...

No. 283 and second stage Able-Star 006) was erected nearly three miles away at Cape Canaveral Pad LC-17B. 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. Nevertheless, SOLRAD 2 did launch, along with Transit 3A (a separate satellite on the same rocket), at 19:50 GMT, 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 In the field of rocketry, range safety may be assured by a system which is intended to protect people and assets on both the rocket range and downrange in cases when a launch vehicle might endanger them. For a rocket deemed to be ''off course' ...

. Like SOLRAD 1 (but no other American launches to date), SOLRAD 2's course to orbit took it over the

Caribbean island The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Se ...

. As a result of the rocket's destruction, fragments fell over Cuba's

Oriente Province Oriente (, "East") was the easternmost province of Cuba until 1976. The term "Oriente" is still used to refer to the eastern part of the country, which currently is divided into five different provinces. Fidel and Raúl Castro were born in a sm ...

at the eastern end of the island, northwest of the U.S. Navy's Guantanamo Bay base. The

Cuban Army The Cuban Revolutionary Army ( es, Ejército Revolucionario) serve as the ground forces of Cuba. Formed in 1868 during the Ten Years' War, it was originally known as the Cuban Constitutional Army. Following the Cuban Revolution, the revolutiona ...

post at

Holguín Holguín () is a municipality and city in Cuba, and the capital of Province of Holguín. After Havana, Santiago de Cuba, and Camagüey, it is the fourth largest city in Cuba. History Before Columbus, the Taino people settled in huts made fro ...

reported fragments falling along a swath and reported recovering "two complete sphere ic 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 Vanguard TV-3 (also called Vanguard Test Vehicle-Three), was the first attempt of the United States to launch a satellite into orbit around the Earth, after the successful Soviet launches of Sputnik 1 and Sputnik 2. Vanguard TV-3 was a small s ...

'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 Palma Soriano is a Cuban city and municipality in the Santiago de Cuba Province. With a population of 125,385 in the city proper, it is the second-largest in the province and the 16th-largest in Cuba. History The city was founded in 1825, uniti ...

. According to a 1988 Chinese document, some of the recovered debris was sold to the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

and used in aid of the design of the second stage of the CSS-4

intercontinental ballistic missile An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons c ...

(ICBM). 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 The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and international security, security, develop friendly relations among nations, achieve international cooperation, and be ...

. In response to these protests, American launches overflying Cuba were postponed, improvements were made to the range-safety system at Cape Canaveral, and future SOLRAD flights were programmed to follow a more northerly course to orbit during launch that did not overfly Cuba.

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 The National Reconnaissance Office (NRO) is a member of the United States Intelligence Community and an agency of the United States Department of Defense which designs, builds, launches, and operates the reconnaissance satellites of the U.S. f ...

(NRO), which elected to continue and expand the GRAB mission starting July 1962 with a next-generation set of satellites, code-named

POPPY A poppy is a flowering plant in the subfamily Papaveroideae of the family Papaveraceae. Poppies are herbaceous plants, often grown for their colourful flowers. One species of poppy, ''Papaver somniferum'', is the source of the narcotic drug opi ...

. 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. 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 The Explorers program is a NASA exploration program that provides flight opportunities for physics, geophysics, heliophysics, and astrophysics investigations from space. Launched in 1958, Explorer 1 was the first spacecraft of the United Stat ...

numbers. The last in this final series of SOLRAD satellites flew in 1976. In all, there were thirteen operational satellites in the SOLRAD series. The GRAB program was declassified in 1998.

References

{{Orbital launches in 1960 1960 in spaceflight Spacecraft launched in 1960 Satellites of the United States 1960 establishments in Florida

Background

Spacecraft

Mission

Legacy

See also

References