Daily Archives: July 10, 2017

10 July 1962

Telstar 1 launches aboard a Thor Delta rocket at Launch Complex 17B, 0835 GMT, 10 July 1962. (NASA)
Telstar 1 launches aboard a Delta rocket at Launch Complex 17B, 0835 GMT, 10 July 1962. (NASA)

10 July 1962: At 0835 GMT (4:35 a.m., EDT) the first communications relay satellite, Telstar 1, was launched into orbit from Launch Complex 17B, Cape Canaveral Air Force Station, Florida. The launch vehicle was a three-stage, liquid-fueled, Delta rocket.

This was the first commercial space flight, sponsored by a consortium of communications companies and government organizations, including AT&T, Bell Labs, the BBC, NASA, and British and French postal services. The satellite was used to relay live television broadcasts across the Atlantic Ocean. This had never previously been possible.

Telstar weighed 171 pounds (77.5 kilograms). Its weight and size were restricted by the availability of launch vehicles. It was placed in an elliptical orbit, varying from 591 miles (952 kilometers) to 3,686 miles (5,933 kilometers), and inclined at about a 45° angle to Earth’s Equator. The orbital period was 2 hours, 37 minutes. The properties of Telstar’s orbit restricted its use to about 20 minutes during each pass.

In addition to its primary role as a communications relay satellite, Telstar also performed scientific experiments to study the Van Allen Belt.

The Delta was a three-stage expendable launch vehicle which was developed from the Douglas Aircraft Company’s SM-75 Thor intermediate-range ballistic missile.

Designated Thor DM-19, the first stage was 60.43 feet (18.42 meters) long and 8 feet (2.44 meters) in diameter. Fully fueled, the first stage had a gross weight of 108,770 pounds (49,337 kilograms). It was powered by a Rocketdyne LR-79-7 engine which burned liquid oxygen and RP-1 (a highly-refined kerosene rocket fuel) and produced 170,565 pounds of thrust (758.711 kilonewtons). This stage had a burn time of 2 minutes, 45 seconds.

The second stage was an Aerojet General Corporation-built Delta 104. It was 19 feet, 3 inches (5.88 meters) long with a maximum diameter of 4 feet, 6 inches (1.40 meters). The second stage had a gross weight of 9,859 pounds (4,472 kilograms). It used an Aerojet AJ10-104 rocket engine which burned a hypergolic  mixture of nitric acid and UDMH. The second stage produced 7,890 pounds of thrust (35.096 kilonewtons) and burned for 4 minutes, 38 seconds.

The third stage was an Allegany Ballistics Laboratory Altair 1. It was 6 feet long, 1 foot, 6 inches in diameter and had a gross weight of 524 pounds (238 kilograms). This stage used a solid-fuel Thiokol X-248 rocket engine, producing 2,799 pounds of thrust (12.451 kilonewtons). Its burn time was 4 minutes, 16 seconds.

The three stages of the Delta rocket accelerated the Telstar satellite to 14,688 miles per hour for orbital insertion.

The day prior to launch, the United States detonated a 1.45 megaton thermonuclear warhead at an altitude of 248 miles (400 kilometers), near Johnston Island in the Pacific Ocean. (Operation Dominic-Fishbowl Starfish Prime). Radiation from this test, combined with residual radiation from the Soviet Union’s  57 megaton detonation over Novaya Zemlya Archipelago (RDS-220, known as “Big Ivan,” or “Tsar Bomba”) on 21 October 1961, damaged the satellite’s circuitry and it went out of service in December 1962.

Engineers were able to work around the damage and restore service by January 1963, but Telstar 1 failed permanently 21 February 1963.

Telstar is still in Earth orbit.

Telstar 1 communications relay satellite. (Bell Laboratories)

© 2016, Bryan R. Swopes

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10 July 1943

U.S. Paratroopers in North Africa prepare to board an 8th Air Force Douglas C-47-DL Skytrain, 41-18341, for Operation Husky, the invasion of Sicily, 9 July 1943.

10 July 1943: Following the defeat of Germany and Italy by the Allies in North Africa, the next phase of the war plan was the invasion of Sicily. This began with the largest airborne assault ever attempted by U.S. and British paratroopers up to that time.

Shortly after midnight, a Regimental Combat Team (RCT) consisting of the 505th Parachute Infantry Regiment with the 3rd Battalion, 504th Parachute Infantry Regiment, under command of Colonel James M. Gavin, United States Army, dropped out of a moonlit sky around Gela on the southern shore of the island and achieved reasonable success. A second airborne assault was carried out by the remainder of the 504th PIR.

Invasion Plan, Invasion of Sicily, 10 July 1943. The airborne assault target is at map coordinates C–2.  (United States Military Academy)

As the Allied formation of 144 Douglas C-47 Skytrain transports approached the Sicilian shoreline, ships of the invasion force mistook them for enemy aircraft and opened fire. 22 C-47s were shot down and many others damaged. 83 men were killed and 318 wounded.

As a result of the friendly fire incident, the airborne assault was widely scattered, missing assigned drop zones and objectives. However, small groups of airborne troopers acting on their own initiative attacked targets of opportunity and kept the island’s defenders off balance.

Coloenel James M. Gavin, United States Army, commanding officer, 505th Parachute Infantry Regimeent, with his men before Operation Husky, 9 July 1943. (U.S. Army)
Colonel James M. Gavin, United States Army, commanding officer, 505th Parachute Infantry Regiment, with his men before Operation Husky, 9 July 1943. (U.S. Army)

© 2016, Bryan R. Swopes

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10 July 1940

The Battle of Britain begins.

“The Few.” Royal Air Force pilots run to their fighters to defend England from attacking German Luftwaffe bombers during the Battle of Britain. (Imperial War Museum)

Before Germany could mount Operation Sea Lion, a cross-channel invasion of the British Isles, it needed to have complete air superiority over the invasion fleet. Because of the Luftwaffe‘s greater numbers and modern aircraft, German military leadership believed this could best be accomplished by defeating the Royal Air Force in air-to-air combat.

The Royal Air Force had been conserving their limited numbers of pilots and aircraft up to this point in the war. Germany’s plan was to send its bombers against targets that the R.A.F. would be forced to defend. The escorting Messerschmitt Bf 109s (also referred to as Me 109) would then shoot down the Boulton Paul Defiants and Bristol Blenheims. But the Hawker Hurricanes and Supermarine Spitfires were up to the task. While the Hurricanes went after the Luftwaffe’s Dornier 17 and Heinkel He 111 bombers, the Spitfires engaged their Bf 109 fighter escorts.

Contrails over London during the Battle of Britain, 10 July–31 October 1940.
Contrails over London during the Battle of Britain, 10 July–31 October 1940.

Britain used a system of radar-directed ground control of its fighter squadrons. The result was that, although both sides lost about the same number of aircraft, the Battle of Britain was a decisive victory for Great Britain. Germany was forced to give up on its plans for an invasion of England.

During a speech the House of Commons, 20 August 1940, Prime Minister Winston Churchill referred to the pilots of Fighter Command when he said,

The gratitude of every home in our Island, in our Empire, and indeed throughout the world, except in the abodes of the guilty, goes out to the British airmen who, undaunted by odds, unwearied in their constant challenge and mortal danger, are turning the tide of the world war by their prowess and by their devotion. Never in the field of human conflict was so much owed by so many to so few.”

Ever since, the Royal Air Force has been known as “The Few.”

Luftwaffe aircraft:

A flight of Dornier Do 17 bombers, circa 1940. (Deutsches Bundesarchiv)
A flight of Dornier Do 17 bombers, circa 1940. (Deutsches Bundesarchiv)
Heinkel He 111 bomber. (Deutsches Bundesarchiv)
Heinkel He 111 bomber. (Deutsches Bundesarchiv)
A flight of Messerchmitt me 109s carry external fuel tanks to extend their range and time over target. (Deutsches Bundesarchiv)
A flight of Messerchmitt Bf 109s carry external fuel tanks to extend their range and time over target. (Deutsches Bundesarchiv)
Messerschmitt Bf 110 twin-engine heavy fighter, circa 1942. (Deutsches Bundesarchiv)
Messerschmitt Bf 110 twin-engine heavy fighter, circa 1942. (Deutsches Bundesarchiv)

Royal Air Force aircraft:

Supermarine Spitfire fighters of No. 610 Squadron, RAF Biggin Hill, during the Battle of Britain. (Imperial War Museum)
Supermarine Spitfire fighters of No. 610 Squadron, RAF Biggin Hill, during the Battle of Britain. (Imperial War Museum)
Hawker Hurrican Mk.I P3408 (VY-K) of No. 85 Squadron, Church Fenton, Yorkshire, October 1940. (B.V. Daventry, RAF official photographer. Imperial War Museum CH 1501)
Hawker Hurricane Mk.I P3408 (VY-K) of No. 85 Squadron, RAF Church Fenton, Yorkshire, October 1940. Flying the same type, also with the identification letters VY-K, Squadron Leader Peter Townsend, DFC, was shot down by a Do 17 named Gustav Marie, over the English Channel, 10 July 1940. After the war, Townsend became good friends with the bomber’s gunner, Werner Borner. (Mr. B.J. Daventry, RAF official photographer. Imperial War Museum CH 1501)

Highly recommended: Duel of Eagles, by Group Captain Peter Townsend, CVO, DSO, DFC and Bar, Royal Air Force. Cassell Publishers Limited, 1970 and Castle Books, 2003.

© 2016, Bryan R. Swopes

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