U2 is a high altitude reconnaissance aircraft. It was developed by the world famous aircraft company Lockheed. Mainly china and USA military forces used U2 to sneak into enemy territories without alerting them. U2 was one of the best spy plane to ever hit service.
Need of U2 spy plane
After the world war ii many countries start working on military solutions to stop WWIII from ever happening. New technologies, new strategies and new machines entered the world.
However, advance technology of a one country is a treat to another. Many countries inventing new ballistic missiles, nuclear bombs and many advance secrete devices was a threat to USA. So, they are in a need to identify the threats before it is too late.
Aircrafts are the best option to under see any location. But, the problem is a country can not violate the air space of another country. In case if US air force reach the Russian air space, for sure they will shoot down the aircrafts.
Advance SAM vehicles and huge radars are always looking at the high skies. So, sending an aircraft to spy on a target is not possible until the U2 was invented.
U2 able of bypassing radar
Radars are electromagnetic wave detectors. They emit signals and receive them back to identify objects. Like any other EMW device radars have limitations.
Some modern planes use radar absorbing materials to minimize reflection. Also, some structural designs are able to minimize radar signature. Supersonic speeds are another option to reach this goal.
But, a typical fighter jet is not able to maintain supersonic speeds for a very long time. Reaching supersonic speeds is a real challenge. Due to the air compression the outer surface of a aircraft can reach very high temperatures.
Above the radar horizon
Radar horizon is the reach limit of a radar. Typically, most radars can only reach altitudes up to 60,000 ft.
U2 was a top secret during its operational days. So, the enemy would never have suspected a spy plane above the horizon.
U2 spy plane has a maximum altitude of 75,000 ft. So, it was difficult for the radars to detect a U2 spy plane flying above the horizon.
Not easy to fly above the horizon
The main challenge of flying in very high altitudes is air pressure and oxygen concentration. When we reach higher altitudes the atmosphere get thinner.
So, the pressure difference between environment and cabin is so high.
Even with normal oxygen masks a person can not breath in high altitudes.
The next problem is extremely low atmospheric pressure. When the air pressure is very low all liquids start to boil at low temperatures. Which mean if you reach 75,000ft without a pressure suite your blood will start to boil.
When oxygen is not enough you fall into a condition called hypoxia. Hypoxia person is not able of making decisions due to low levels of brain activities.
U2 spy plane successfully facing the challenges
However U2 faced all these problems with good solutions. Pilots for U2 planes got an advance training. Only the best of the best was able to become a U2 pilot.
During the training both pilots physical and mental abilities were tested.
A special pressurised suit was introduced. This act almost like a space suit. Pressure suit help pilots to maintain air pressure on body to avoid blood boiling.
An advance oxygen supply system was installed in U2 with a backup system. During the training pilots got the training on working under low oxygen conditions.