Tag Archives: Two-Stage Rocket

24 July 1950

Bumper 8 launch at Launch Complex 3, Cape Canaveral Air Force Station, Florida, 24 July 1950. The wooden structure in the foreground houses the firing crew and support personnel. (NASA)

24 July 1950: The first rocket launch at Cape Canaveral, Florida, took place. Bumper 8 was a two-stage rocket consisting of a captured German V-2 ballistic missile as the first stage and a WAC Corporal sounding rocket as the upper, second, stage. The rocket lifted off from Launch Complex 3 at the Cape Canaveral Air Force Station and followed a ballistic trajectory over the Joint Long Range Proving Ground. This was a low-angle atmospheric flight. The WAC Corporal reached an altitude of 10 miles (16.1 kilometers) and traveled 200 miles (322 kilometers) downrange.

The Bumper Project was a U.S. Army Ordnance Corps program, with overall responsibility contracted to the General Electric Corporation. The V-2s used in the Bumper Project were modified at accept the WAC Corporal second stage. Compressed air was used to separate the stages after the V-2 engine was cut off.

The V2, or Vergeltungswaffen 2 (also known as the A4, Aggregat 4) was a ballistic missile weighing 28,000 pounds (12,500 kilograms) when fully loaded. It carried a 2,200 pound (1,000 kilogram) explosive warhead of amatol, a mixture of TNT and ammonium nitrate. Propellant was a 75/25 mixture of of ethanol and water with liquid oxygen as oxidizer.

When launched, the rocket engine burned for 65 seconds, accelerating the rocket to 3,580 miles per hour (5,761 kilometers per hour) on a ballistic trajectory. The maximum range of the rocket was 200 miles (322 kilometers) with a peak altitude between 88 and 128 miles (142–206 kilometers), depending on the desired range. On impact, the rocket was falling at 1,790 miles per hour (2,881 kilometers per hour).

The V-2 could only hit a general area and was not militarily effective. Germany used it against England, France, The Netherlands and Belgium as a terror weapon. More than 3,200 V-2 rockets were launched against these countries.

At the end of World War II, many V-2 rockets and components were captured by Allied forces and were brought to the United States for research, along with many of the German engineers, scientists and technicians who had worked on the German rocket program. Others were captured by the Soviet army.

Bumper 8 supported by a gantry at Launch Complex 3, Cape Canaveral Air Force Station, Florida. (U.S. Army)

The WAC Corporal was a liquid-fueled hypergolic rocket. After separation from the first stage, the WAC Corporal was capable of reaching more than 80 miles (129 kilometers). It was designed by the Jet Propulsion Laboratory in Pasadena, California, and built by Douglas Aircraft. The rocket carried small research packages into the upper atmosphere. The two-stage rocket was used to develop launch techniques and to refine the separation of upper stages at very high speed.

Now named the Kennedy Space Center, but known simply as “The Cape,” the location was selected to allow rocket testing to take place over the Atlantic Ocean, minimizing danger to persons and property. As one of the points within the United States closest to the Equator, rockets launched on an eastward trajectory receive additional velocity due to the Earth’s rotation.

Launch Pad 3 at Cape Canaveral, circa 1950. A rocket is on the pad surrounded by the gantry structure. (U.S. Air Force)
Launch Complex 3 at Cape Canaveral, 28 July 1950. The Bumper 7 two-stage rocket is on the pad surrounded by a gantry structure. It was launched the day after this photograph was taken. (U.S. Air Force)

© 2016, Bryan R. Swopes

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29 May 1947, 0130 GMT

Hermes II (NASA)

29 May 1947: At 1930 hours, Mountain Daylight Time, a Hermes II two-stage, liquid-fueled rocket was launched from Launch Complex 33 at southern end of the White Sands Proving Grounds, east of Las Cruces, New Mexico.

White Sands Proving Grounds Gate sign

Earlier in the day, a launch attempt failed when the first stage engine failed to produce thrust. Repairs were made and the second attempt succeeded—sort of. . .

The plan was for the rocket to arc toward the north, heading for the far end of the proving grounds. Instead, the Hermes II arced to the SOUTH.

The Range Safety Officer was prevented from sending a DESTRUCT signal when a program scientist physically restrained him. The rocket peaked at 35 nautical miles (65 kilometers), passed over Fort Bliss and El Paso, and after about five minutes of flight, hit the ground about one-half mile from the Buena Vista Airport in Ciudad Juárez, Mexico.

People standing on the rim of the crater on the night of 29 May 1947. (El Paso Times)

At impact, the rocket dug a crater 50 feet (15.2 meters) across and 24 feet (7.3 meters) deep. The explosion shook buildings in El Paso and 25 miles (40 kilometers) away in Fabens, Texas. The rocket barely missed a powder magazine where mining companies were storing dynamite and other explosives.

Fortunately, there were no injuries, and property damage was minor.

Hermes II crater near Ciudad Juárez, Mexico. The crater is approximately  50 feet across and 24 feet deep, (White Eagle Aerospace)

Hermes II was the world’s first multi-stage rocket. Developed from the German V-2 rocket (Vergeltungswaffen 2), it was intended to serve as a test bed for ramjet development. The upper stage had a broad wing for flight tests of a split-wing two-dimensional ducted-airfoil ramjet. (For this launch the ramjet was not operational.) The span of the fins were increased to improve stability.

The Hermes II was 51.50 feet (15.70 meters) tall. The tail fins had a span of 17.75 feet (5.41 meters), and the second stage wing span was 15.26 feet (4.65 meters). The rocket had a gross weight of 31,750 Pounds (14,400 kilograms). The liquid oxygen/alcohol-fueled engine produced 60,000 pounds of thrust (267 kilonewtons).

In 1948, the Hermes II was redesignated RTV-G-3 by the U.S. Army.

© 2019, Bryan R. Swopes

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