Ariane 5 is a space launch vehicle produced and launched by the European Space Agency. It took 10 years to develop and cost $7 billion. Ariane 4 was not directly improved.
ESA originally designed the Ariane 5 to launch Hermes. However, the Hermes was canceled, and the Ariane 5 became a purely unmanned space launch vehicle.
Ariane 5's first stage rocket is called EPC and has a diameter of 5.4 m and a height of 30.5 m. The EPC consists of two tanks, large and small, with 130 tons of liquid oxygen in the upper small tank and 25 tons of liquid hydrogen in the lower tank, and the bottom has a thrust of 115 tf (1130 kN). It is equipped with a Vulcan engine. The mass of the EPC is about 15 tonnes without fuel.
Each side of the EPC is equipped with a pair of solid rocket boosters P238. Each weight of P238 is about 227 t, which can produce an output of 630 tf (6200 kN). This booster is retrieved by parachute in the same way as the solid propulsion booster on the space shuttle. However, unlike the space shuttle, which reuses boosters, it is collected for inspection and is not reused.
The second stage is above the first stage. While the Ariane 5 ECA is equipped with an ESC that uses the HM7B engine with excellent non-propelling power using cryogenic fuel of liquid hydrogen and liquid oxygen, the Ariane 5G is equipped with EPS fueled by monomethyl hydrazine and dinitrogen tetraoxide. The second stage is covered with a payload payload and a streamlined fairing protecting the payload. This cover is intended to be removed upon reaching a sufficient altitude. In addition, a module called Spectra or Sirda that stores satellites is used to repeatedly mount one satellite and fairing on top of it, and it is used for simultaneous launch of multiple satellites.
Details of each stage
The first launched Ariane 5G had a launch weight of 737 tons, which could carry a 5970 kg payload to the geostationary transition orbit, but later the maximum payload was increased to 6200 kg.
The Ariane 5G+, which was upgraded from the Ariane 5G, increased the payload to the geostationary transition orbit to 6950 kg, and was launched three times in 2004.
The Ariane 5GS, first launched in 2005, was equipped with the same solid booster as the Ariane 5ECA, and the Vulcan 1B engine was also upgraded, capable of carrying 6100 kg to the geostationary transition orbit.
The Ariane 5 ECA was capable of carrying up to 10000 kg of two payloads combined, or a single payload of up to 10500 kg on a geostationary transition orbit. In this modification, a Vulcan 2 engine was used for the first stage and an HM7B engine was used for the second stage. This second stage has a mass of 2100 kg in an empty state, and 14000 kg of propellant can be loaded. The HM7B was previously used as the 3rd stage engine of the Ariane 4. The improved Vulcan 2 engine is longer than the previous Vulcan engine, and the nozzle and flow cycle efficiency is improved, resulting in improved mixing ratio. This mixing ratio was realized by adjusting the length of the tank in the first stage. In addition, the solid booster is lighter by the new welding method. The cryogenic stage of ESC-A exerts great power for the launch of geostationary satellites, but it is not used for ATV launches because a significant performance improvement cannot be expected for launch from low orbit.
The Ariane 5 ES-ATV is for ATV only, it is an improved Ariane 5 ECA and is used for launching ATVs. The second stage EPS uses Ariane 5G's. It has the ability to carry a 21000 kg payload into low orbit.
The Ariane 5 ECB features a new cryogenic top. ECB is a geostationary transition trajectory.