There are now several civilian providers of high resolution satellite imagery, notably GeoEye and Digital Globe, as well as smaller lower resolution imagery providers, such as DMC International Imaging (DMCII) and RapidEye, but it was not always this way. In the wake of the alarming Soviet Sputnik I launch in 1958, (from an American perspective), the United States of America (USA), under President Eisenhower, initiated the secret Corona satellite reconnaissance program managed jointly by the Central Intelligence Agency (CIA) and the US Air Force (USAF). The program arose as a concerted response to several significant Soviet advances in space technologies, resulting in 1960, with the launch of the USA’s own first spy satellite whose first images of the Soviet Union weren’t declassified until as late as 1995. Besides Sputnik the Soviet Union launched over 500 Zenit military spy satellites between 1961-1994, under the name Kosmos, typically having a spherical re-entry capsule 2.3m in diameter and a mass of about 2400kg. In due course the US government launched its first commercial satellite, the ERTS-1 (Earth Resources Technology Satellite)- later renamed Landsat, the first of a long series of successful earth observation satellites, and it is upon the twin pillars of civilian earth observation and military reconnaissance that modern humanitarian satellite imaging stands. For the first time, satellite imagery became available for non-military use, but ground resolution, by comparison with military surveillance satellite imagery, was extremely poor.
The Cold War birthed a number of revolutionary technologies, themselves conceived during or prior to the Second World War, such as satellite imaging and satellite communications- wonders of an age used almost exclusively by competing military forces across the divide of the Iron Curtain. Environmentally relevant imagery of our planet taken by such intelligence satellites was then highly classified, and relatively few people had access to the imagery. Although satellites were developed and used for diverse civilian applications, such civilian satellites were initially ‘behind the curve’ of military developments. This state of affairs began to change in the mid 1980’s and early 1990’s when a few other countries launched some capable Earth-imaging satellites and made that imagery available for sale.
The first French earth observation SPOT satellite, launched in 1986, in timely fashion collected images of the Chernobyl nuclear power plant disaster in the Ukraine, a country formerly part of the Soviet Union. Chernobyl is just over 100km north of Kiev and SPOT images of the 26 April Reactor 4 disaster were shown to the free world several days later, with the USSR silent at first, unwilling to release information about the disastrous meltdown. Chernobyl imagery also showed a significant temperature drop in the cooling lake after the event. In the same year the UN General Assembly adopted the "Principles Relating to Remote Sensing of the Earth from Outer Space” that allowed imaging satellites to pass over any nation as long as the imagery was made available to the sensed state “on reasonable cost terms."
In 1992, the Russian government became the first nation to market high-resolution satellite imagery from their military satellites, recognizing the potential to generate vital overseas revenue at a critical time for Russia and its former CIS states . However, commercially available imagery was degraded to provide a resolution of 2 m . In March 1994 the Clinton administration responded by adopting the Presidential Decision Directive to encourage civilian private companies in the USA to sell high-resolution satellite imagery. After the US Government took this step it permitted private companies to both start building and launching satellites with 1 m resolution capability- and Pandora’s box was opened. This decision pressed the Russian government to raise its own stakes by permitting sale of 1 m resolution imagery by the autumn of 1999. However, they notably omitted sale of imagery from ‘friendly countries’ such as North Korea. Other nations allowing military and civilian industries to market satellite imagery include: France, Israel, India and Japan .
Landsat is without doubt the longest running satellite program for earth observation imagery, with the most recent Landsat 7 launched in April 1999. Landsat instruments have acquired many millions of images, and are a vital resource for global change research and diverse applications in: agriculture, geology, forestry, regional planning, surveillance, education, and of course, national security. National Space Policy Directive 5, signed by President Bush in 1992, reiterated the importance of the Landsat program. "Development of the commercial space remote sensing industry in the United States and promoting the broad use of remote sensing data" must be balanced against "preserving the national security of the United States." President Clinton further signed Presidential Decision Directive 23 in 1994, laying the foundation for US companies to launch their own high-resolution satellites, working in parallel with US governmental and military requirements. In 2002, the Director of the CIA issued a strategically defining memorandum that stated, "It is the policy of the intelligence community to use US commercial space imagery to the greatest extent possible." Furthermore in 2003, President George W. Bush III issued National
Security Presidential Directive 27, stating that the "fundamental goal of US commercial remote sensing policy is to advance and protect US national security and foreign policy interests by maintaining the nation’s leadership in remote sensing space activities."
Only as recently as 2009, the [U.S.] Director of National Intelligence and the Department of Defense (DoD) issued a joint press release saying they have put together a plan "to modernize the nation's ageing satellite-imagery architecture by prudently evolving government-owned satellite designs and enhancing use of U.S. commercial providers." In this way the technological advances in civilian imagery have turned full circle back into imagery provision for the military- making this from a humanitarian perspective, a double-edged sword, very much dependent on the motives and aspirations of the military user.
The Corona program
Modern high resolution civilian satellite imaging has much to thank earlier ‘covert’ military satellite programs. The Corona program, for example, was America’s first serious series of strategic reconnaissance satellites built and operated by the CIA with assistance from the USAF. Corona satellites were used specifically for photographic surveillance of the former Soviet Union, the People's Republic of China, and other places of interest/threat between June 1959 and May 1972. Corona satellites were designated: KH-1 to KH-4, KH-4A and KH-4B, with KH standing for "Key Hole" . In total there were some 144 Corona satellites launched, of which 102 returned usable photographs, a noteworthy accomplishment.
Corona began covertly as "Discoverer", part of the USAF satellite reconnaissance and protection program in 1956. By May 1958, the DoD had transferred Discover to the Defense Advanced Research Projects Agency (DARPA), the same agency responsible for helping create DARPANET- the forerunner of the Internet. The project was accelerated following the unfortunate shooting down of Gary Power’s U-2 spy plane over the Soviet Union in May 1960 which resulted in a hugely embarrassing show trial in Moscow.
The Corona satellites used special 70mm film with a 61 cm focal length camera  manufactured by Eastman Kodak with a resolution of 170 lines per mm [6-7]. The amount of film carried by the satellites was unsurprisingly increased over time, initially each satellite carried some 2,400 m of film for each camera, but by the 5th satellite generation (KH-5) they carried 4,900 m of film each . Most of the film was black and white, but IR (IR) film was used as well as film. However, color film had lower resolution than black and white film, and was discontinued . Cameras were manufactured by the Itek Corporation and further details can be found elsewhere  with the first such camera able to resolve images of ground objects some 12 m in diameter. Imaging systems improved rapidly, and the KH-3 could ‘see’ objects as small as 3.0 m in diameter, whilst later missions could resolve smaller objects only 1.5 m in size .
The first Corona satellites orbited at altitudes 160 km above earth, with later missions orbiting as low as 121 km . Space developed film was retrieved from orbit via a reentry capsule, which separated from the satellite and fell back to earth . After reentry the heat shield surrounding the re-entry vehicle was released some 20 km up and a parachute system deployed. The capsule was intended to be caught mid-air by a passing airplane towing a claw which would winch it aboard, or it could land at sea. A salt plug in the capsule’s base would dissolve after 2 days, allowing the capsule to sink if not retrieved by the US Navy so it did not fall into enemy hands .
Coronas were launched on Thor-Agena rockets, with a Thor first stage and an Agena booster (the 2nd stage of the rocket lifting the Corona into orbit). Maneuvering rockets were added to the satellite later in the series in 1963. Corona orbited in low orbits to enhance the resolution of its camera system, but at perigee (the lowest pointing orbit), Corona suffered substantial drag from earth's atmosphere which over time caused orbital decay, forcing satellites to re-enter the atmosphere earlier than planned. Maneuvering rockets boosted Corona into higher near polar orbits, and increased the available mission time . However, the all-important decisions regarding what to photograph were made by the Corona Target Program. Software, run by an on-board computer unsophisticated by modern standards, was programed to operate the cameras based on: intelligence of the selected targets to be imaged, weather, the satellite operational status, and what images had already been captured.
As stated earlier the first dozen Corona launches were disguised as part of a space technology development program- the Discoverer program whose first test launches were carried out in 1959 with the first Corona camera launch carried out in June 1959 under the name Discoverer 4.
A notable next development was the return capsule of the Discoverer 13 mission, launched August 10, 1960, and then recovered the next day . This was the first time any object had been recovered successfully from orbit. After the Discoverer 14 launch on August 18, 1960, its film bucket was amazingly retrieved 2 days later by a C-119 transport plane. This was the first successful return of photographic film from orbit. Meanwhile by comparison with the Soviets, Sputnik 5 was launched into orbit August 19, 1960, one day after Discoverer 14. Sputnik 5 took two Soviet space dogs, Belka and Strelka into orbit, and returned them to earth . Following this last Discoverer, the remaining launches of Corona satellites were entirely top secret with the final Corona launch taking place in May 1972.
The Corona program was officially classified top secret until 1992. In February 1995, photos taken by Corona satellites, and 2 other programs (Argon and KH-6 Lanyard) were also declassified by President Clinton. Further review by experts of the "obsolete
broad-area film-return systems other than Corona" mandated by President Clinton's order led to further declassification in 2002 of photos from the KH-7 and the KH-9 low-resolution cameras- paving the way for potential imagery applications.
Revealing the secret places - The Cuban Missile Crisis
Secret spaces cover a wide range of places and facilities, and not just military ones. All nation-states operate systems to protect their own security, and many of these systems depend upon keeping critical information relating to locations, hidden from both citizens as well as foreigners who could threaten the powerbase of those who rule. And in this ‘great game of the high frontiers’ the historical military value of high resolution imagery from aircraft or satellite is undisputed. U-2 photographs taken on 18th October 14, 1962, in which analysts under Charles Lundahl's (1915-1992) direction, found clear visual evidence of the placement of Soviet SS-4 Medium Range Ballistic Missiles (MRBM), capable of hitting targets in the continental United States with nuclear warheads . This discovery triggered the Cuban Missile Crisis, sending the US intelligence community into a frenzy of satellite based imagery acquisition and triggering an unprecedented military alert. The October 16 briefing of President Kennedy, confirmed a Soviet weapons' presence, which had not been expected by the intelligence community or military.
Principally as a result of the photographic information and the diplomatic discussions that resulted from this image-derived knowledge. President Kennedy pressured the Soviets to remove the missiles from Cuban soil. However, recovery of the all-important Cold War ‘wet’ film did not always go to plan. The 1963 thriller novel Ice Station Zebra by Alistair McLean and its 1968 film adaptation were inspired, in part, by accounts from April 1959, of a missing experimental Corona satellite capsule (Discoverer II) that inadvertently landed near Spitzbergen. Whilst Soviet agents may have recovered the film capsule , it is more likely that the capsule landed in water and sank! A wider discussion of secret spaces, especially in the post 9/11 world and its perception of geopolitical threats is discussed in detail by Perkins and Dodge .
1. Stix, G, Public Eye, Scientific American, August 1996
2. Vivin, G, New Satellite Images for Sale, International Security, Vol. 20. No. 1 (Summer 1990), p98.
3. Ibid, Vivin, G, pp. 99-105 and p 119.
4. Yenne, Bill (1985). The Encyclopedia of US Spacecraft. Exeter Books (A Bison Book), New York. ISBN 0-671-07580-2, p.82.
5. Yenne, Bill (1985). The Encyclopedia of US Spacecraft. Exeter Books (A Bison Book), New York. ISBN 0-671-07580-2, p.63.
6. Drell, Sidney D. ‘Physics and U.S. National Security.’ Reviews of Modern Physics. 71:2 (1999), p. S460-S470.
7. Brown, Stewart F. ‘America's First Eyes in Space’ Popular Science. February 1996, p. 46.
8. Drell, Sidney D. ‘Physics and U.S. National Security’ Reviews of Modern Physics. 71:2 (1999), p. S462.
9. Olsen, Richard C. ‘Remote Sensing From Air and Space’. Bellingham, Wash.: SPIE Press, 200, p. 57.
10. Smith, F. Dow. ‘The Design and Engineering of Corona's Optics’ in CORONA: Between the Sun & the Earth: The First NRO Reconnaissance Eye in Space. Robert McDonald, ed. Bethesda, Md.: ASPRS, 1997, pp. 111-114.
11. Chun, Clayton K.S. ‘Thunder Over the Horizon: From V-2 rockets to Ballistic Missiles’ Westport: Praeger Security International, 2006, p.75.
12. Peebles, Curtis. ‘The Corona Project: America's First Spy Satellites’ Annapolis, Md.: Naval Institute Press, 1997, p. 48.
13. Monmonier, Mark S. ‘Spying With Maps: Surveillance Technologies and the Future of Privacy’ Chicago: University of Chicago Press, 2004, p. 23.
14. Ruffner, Kevin C., ed. Corona: America's First Satellite Program. New York : Morgan James, 1995, p. 32-33.
17. ‘The "Milk Run" U-2 Mission of October 14’ (PDF). Naval Historical Center. n.d. NHC-Cuba.http://www.history.navy.mil/download/cuba-mc/cmc18-21.pdf. Retrieved 2007-09-16.
18. National Reconnaissance Office. ‘National Reconnaissance Office Review and Redaction Guide for Automatic Declassification of 25-Year-Old Information’ Version 1.0, 2006 edition, p. 154. Accessed 2012-06-06.
19. Perkins, C., Dodge, M., ‘Satellite imagery and the spectacle of secret spaces.’, Geoforum, pp. 546-560, 40 (2009).
20. Short, N.M. ‘The LANDSAT Tutorial Workbook: Basics of Satellite Remote Sensing’. NASA Reference Publication 1078.NASA. http://hdl.handle.net/2060/19830002188
. Retrieved 20 September 2011.
23. Willum, B, ‘Human Rights Abuses Monitored with Satellite Imagery: Myth or Reality?’ Submitted for the Degree of Master of Arts in War Studies, The Department of War Studies, King’s College London, 1 September 1999.
Reprint with permission by Chris Lavers, author of “Recent Developments in Remote Sensing for Human Disaster Management and Mitigation- Natural and Man-made 2013 - Spotlight on Africa”