[5] The system was designed as an expendable launch vehicle by the Centre national d'études spatiales (CNES), the French government's space agency, in cooperation with various European partners.

Despite not being a direct derivative of its predecessor launch vehicle program, it was classified as part of the Ariane rocket family.

Attached to the sides were two P241 (P238 for Ariane 5G and G+) solid rocket boosters (SRBs or EAPs from the French Étages d'Accélération à Poudre), each weighing about 277 t (611,000 lb) full and delivering a thrust of about 7,080 kN (1,590,000 lbf).

The SRBs were usually allowed to sink to the bottom of the ocean, but, like the Space Shuttle Solid Rocket Boosters, they could be recovered with parachutes, and this was occasionally done for post-flight analysis.

[citation needed] The French M51 submarine-launched ballistic missile (SLBM) shared a substantial amount of technology with these boosters.

[10] In February 2000, the suspected nose cone of an Ariane 5 booster washed ashore on the South Texas coast, and was recovered by beachcombers before the government could get to it.

[12][13] The payload and all upper stages were covered at launch by a fairing for aerodynamic stability and protection from heating during supersonic flight and acoustic loads.

[23][24] Total launch price of an Ariane 5 – which could transport up to two satellites to space, one in the "upper" and one in the "lower" positions – was around €150 million as of January 2015[update].

[26][27] The launcher was also to include a lengthened fairing up to 20 m (66 ft) and a new dual launch system to accommodate larger satellites.

Compared to an Ariane 5ECA model, the payload to GTO was to increase by 15% to 11,500 kg (25,400 lb) and the cost-per-kilogram of each launch was projected to decline by 20%.

However, the failure of the first ECA flight in 2002, combined with a deteriorating satellite industry, caused ESA to cancel development in 2003.

A new composite steerable nozzle was developed while new thermal insulation material and a narrower throat improved the expansion ratio and subsequently the overall performance.

[27][34] The incorporation of the ESC-B with the improvements to the solid motor casing and an uprated Vulcain engine would have delivered 27,000 kg (60,000 lb) to LEO.

[36] However, after several permutations the finalized design was nearly identical in performance to the Ariane 5,[37] focusing instead on lowering fabrication costs and launch prices.

The software had been written for the Ariane 4 where efficiency considerations (the computer running the software had an 80% maximum workload requirement[41]) led to four variables being protected with a handler while three others, including the horizontal bias variable, were left unprotected because it was thought that they were "physically limited or that there was a large margin of safety".

[42] Another partial failure occurred on 12 July 2001, with the delivery of two satellites into an incorrect orbit, at only half the height of the intended GTO.

The ESA Artemis telecommunications satellite was able to reach its intended orbit on 31 January 2003, through the use of its experimental ion propulsion system.

The first launch of the ECA variant on 11 December 2002 ended in failure when a main booster problem caused the rocket to veer off-course, forcing its self-destruction three minutes into the flight.

On 18 July 2004, an Ariane 5G+ boosted what was at the time the heaviest telecommunication satellite ever, Anik F2, weighing almost 6,000 kg (13,000 lb).

[46] On 9 March 2008, the first Ariane 5ES-ATV was launched to deliver the first ATV called Jules Verne to the International Space Station (ISS).

The satellite was launched into a lower-energy orbit than a usual GTO, with its initial apogee at roughly 17,900 km (11,100 mi).

[52] The precision of trajectory following launch led to fuel savings credited with potentially doubling the lifetime of the telescope by leaving more hydrazine propellant on board for station-keeping than was expected.

[52][53] According to Rudiger Albat, the program manager for Ariane 5, efforts had been made to select components for this flight that had performed especially well during pre-flight testing, including "one of the best Vulcain engines that we've ever built.

"[53] On 22 April 2011, the Ariane 5ECA flight VA-201 broke a commercial record, lifting Yahsat 1A and Intelsat New Dawn with a total payload weight of 10,064 kg (22,187 lb) to transfer orbit.

[56] In June 2016, the GTO record was raised to 10,730 kg (23,660 lb),[57] on the first rocket in history that carried a satellite dedicated to financial institutions.

It was later confirmed, about 1 hour and 20 minutes after launch, that both satellites were successfully separated from the upper stage and were in contact with their respective ground controllers,[61] but that their orbital inclinations were incorrect as the guidance systems might have been compromised.

[62] SES-14 needed about 8 weeks longer than planned commissioning time, meaning that entry into service was reported early September instead of July.

[65] As of 16 February 2018, Al Yah 3 was approaching the intended geostationary orbit, after series of recovery maneuvers had been performed.