|Tillman, Barret. Alpha Bravo Delta Guide to the US Air Force. Indianaplois, IN: Alpha Books, 2003.||"The SR-71 held the absolute speed record of 2,193 mph and an altitude record of 85,000 feet."||25,900 m|
|The Spy Planes:What They Do and Why. Time. (25 April 1964).||"The less spectacular type of spy plane is the slower patrol aircraft that measures radar capabilities and eavesdrops obliquely on enemy radio communications from a distance … The EC-121's working altitude of 25,000 ft. gives its snooping gear a much wider reach than that of a surface ship like Pueblo."||7,620 m|
|Aviation First for Robotic Spy Plane. BBC News. 24 April 2001.||"An unmanned high-altitude spy plane has made aviation history by completing the first non-stop, robotic flight across the Pacific from California to Australia, US defence officials said on Tuesday. The Global Hawk, a jet-powered aircraft, flew from Edwards Air Force Base in California and landed late on Monday at the Royal Australian Air Force base at Edinburgh, in South Australia.The 13,840 km (8,600 mile) flight, at an altitude of almost 20 km (12.5 miles), took 22 hours and set a world record for the furthest a robotic aircraft has flown between two points."||< 20,000 m|
Spy planes have been used for many decades for surveillance purposes. In order for these planes to fly over areas of land and not be detected, they must fly at a high altitude. The altitude of a spy plane is very important for it to stay out of reach of radar, so it won't be detected, and missiles.
One of the first spy planes was the U-2. It was designed in America and was used during the Cold War in the 1950s. The altitude at that time for a spy plane was around 21,000 M. At first, the altitude seemed high enough to stay out of Soviet radar while the US was flying over Russia. The U-2 was the first of many spy planes that would follow.
In 1964 the SR-71 Blackbird made its first flight. This spy plane broke all records flying at 3,529 km/h (2,193 mph or Mach 3) and 25,900 M. This plane flew at such great speeds and altitude that it was never shot down while in flight. The SR-71 was a great technological advancement during its time, but in today's times, technology is the number one thing that is driving people to design better equipment.
In 2001, the Global Hawk made its first flight. This was the first high-altitude spy plane completing the first non-stop flight across the Atlantic. The amazing thing was, it was a robotic plane. The Global Hawk flies at 20,000 m and has no pilot. The course of flight is pre-set from take off all the way to landing. Pictures and flight are all controlled electronically and a pilot monitors the plane by using a sensor suit that provides infra-red and visual images.
Every time a new spy plane is developed, it pushes the limit with new technology. What started out with a regular plane that was man driven at 21,000 m is now replaced with planes that can fly at much higher speeds and altitude or without being flown by a pilot.
Michael Calamera -- 2004