Ariane 5
Notable launches
Notable launches
----------------

[thumb\|upright\=1\.0\|right\|Launch of the 34th Ariane 5 from [Guiana Space Centre](/wiki/Guiana_Space_Centre "Guiana Space Centre")](/wiki/File:Ariane_5_10_2007.ogv "Ariane 5 10 2007.ogv")

Ariane 5's first test flight ([Ariane 5 Flight 501](/wiki/Ariane_5_Flight_501 "Ariane 5 Flight 501")) on 4 June 1996 failed, with the rocket self\-destructing 37 seconds after launch because of a malfunction in the control software. A data conversion from 64\-[bit](/wiki/Bit "Bit") [floating\-point](/wiki/Floating-point_arithmetic "Floating-point arithmetic") value to 16\-bit [signed](/wiki/Signedness "Signedness") [integer](/wiki/Integer "Integer") value to be stored in a variable representing horizontal bias caused a processor trap (operand error) because the floating\-point value was too large to be represented by a 16\-bit signed integer. The software had been written for the [Ariane 4](/wiki/Ariane_4 "Ariane 4") where efficiency considerations (the computer running the software had an 80% maximum workload requirement) led to four variables being protected with a [handler](/wiki/Exception_handling "Exception handling") 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". The software, written in [Ada](/wiki/Ada_%28programming_language%29 "Ada (programming language)"), was included in the Ariane 5 through the reuse of an entire Ariane 4 subsystem despite the fact that the particular software containing the bug, which was just a part of the subsystem, was not required by the Ariane 5 because it has a different preparation sequence than the Ariane 4\.

The second test flight (L502, on 30 October 1997\) was a partial failure. The Vulcain nozzle caused a roll problem, leading to premature shutdown of the core stage. The upper stage operated successfully, but it could not reach the intended orbit. A subsequent test flight (L503, on 21 October 1998\) proved successful and the first commercial launch (L504\) occurred on 10 December 1999 with the launch of the [XMM\-Newton](/wiki/XMM-Newton "XMM-Newton") X\-ray observatory satellite.

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](/wiki/Artemis_%28satellite%29 "Artemis (satellite)") [telecommunications satellite](/wiki/Telecommunications_satellite "Telecommunications satellite") was able to reach its intended orbit on 31 January 2003, through the use of its experimental [ion propulsion](/wiki/Ion_propulsion "Ion propulsion") system.

The next launch did not occur until 1 March 2002, when the [Envisat](/wiki/Envisat "Envisat") [environmental satellite](/wiki/Environmental_satellite "Environmental satellite") successfully reached an orbit of  above the [Earth](/wiki/Earth "Earth") in the 11th launch. At , it was the heaviest single payload until the launch of the [first ATV](/wiki/Jules_Verne_ATV "Jules Verne ATV") on 9 March 2008, at .

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. Its payload of two communications satellites ([STENTOR](/wiki/STENTOR_%28satellite%29 "STENTOR (satellite)") and [Hot Bird 7](/wiki/Hot_Bird_7 "Hot Bird 7")), valued at about €630 million, was lost in the [Atlantic Ocean](/wiki/Atlantic_Ocean "Atlantic Ocean"). The fault was determined to have been caused by a leak in coolant pipes allowing the nozzle to overheat. After this failure, [Arianespace SA](/wiki/Arianespace "Arianespace") delayed the expected January 2003 launch for the [Rosetta](/wiki/Rosetta_space_probe "Rosetta space probe") mission to 26 February 2004, but this was again delayed to early March 2004 due to a minor fault in the foam that protects the cryogenic tanks on the Ariane 5\. The failure of the first ECA launch was the last failure of an Ariane 5 until [flight 240](/wiki/Ariane_flight_VA241 "Ariane flight VA241") in January 2018\.

On 27 September 2003, the last Ariane 5G boosted three satellites (including the first European lunar probe, [SMART\-1](/wiki/SMART-1 "SMART-1")), in Flight 162\. On 18 July 2004, an Ariane 5G\+ boosted what was at the time the heaviest telecommunication satellite ever, [Anik F2](/wiki/Anik_%28satellite%29 "Anik (satellite)"), weighing almost .

The first successful launch of the Ariane 5ECA took place on 12 February 2005\. The payload consisted of the [XTAR\-EUR](/wiki/XTAR-EUR "XTAR-EUR") military communications satellite, a 'SLOSHSAT' small scientific satellite and a MaqSat B2 payload simulator. The launch had been scheduled for October 2004, but additional testing and a military launch (of a [Helios 2A](/wiki/Helios_2_%28satellite%29 "Helios 2 (satellite)") observation satellite) delayed the attempt.

On 11 August 2005, the first Ariane 5GS (featuring the Ariane 5ECA's improved solid motors) boosted [Thaicom 4](/wiki/Thaicom_4 "Thaicom 4"), the heaviest telecommunications satellite to date at , into orbit.

On 16 November 2005, the third Ariane 5ECA launch (the second successful ECA launch) took place. It carried a dual payload consisting of [Spaceway F2](/wiki/Spaceway-2 "Spaceway-2") for [DirecTV](/wiki/DirecTV "DirecTV") and [Telkom\-2](/wiki/Telkom-2 "Telkom-2") for [PT Telekomunikasi](/wiki/Telkom_Indonesia "Telkom Indonesia") of [Indonesia](/wiki/Indonesia "Indonesia"). This was the launch vehicle's heaviest dual payload to date, at more than .

On 27 May 2006, an Ariane 5ECA launch vehicle set a new commercial payload lifting record of . The dual\-payload consisted of the [Thaicom 5](/wiki/Thaicom_5 "Thaicom 5") and [Satmex 6](/wiki/Eutelsat_113_West_A "Eutelsat 113 West A") satellites.

On 4 May 2007, the Ariane 5ECA set another new commercial record, lifting into transfer orbit the [Astra 1L](/wiki/Astra_1L "Astra 1L") and [Galaxy 17](/wiki/Galaxy_17 "Galaxy 17") communication satellites with a combined weight of , and a total payload weight of . This record was again broken by another Ariane 5ECA, launching the [Skynet 5B](/wiki/Skynet_5B "Skynet 5B") and [Star One C1](/wiki/Star_One_C1 "Star One C1") satellites, on 11 November 2007\. The total payload weight for this launch was of .

On 9 March 2008, the first Ariane 5ES\-ATV was launched to deliver the first [ATV](/wiki/Automated_Transfer_Vehicle "Automated Transfer Vehicle") called *[Jules Verne](/wiki/Jules_Verne_ATV "Jules Verne ATV")* to the [International Space Station](/wiki/International_Space_Station "International Space Station") (ISS). The ATV was the heaviest payload ever launched by a European launch vehicle, providing supplies to the space station with necessary propellant, water, air and dry cargo. This was the first operational Ariane mission which involved an engine restart in the upper stage. The ES\-ATV Aestus EPS upper stage was restartable while the ECA HM7\-B engine was not.

On 1 July 2009, an Ariane 5ECA launched [TerreStar\-1](/wiki/TerreStar-1 "TerreStar-1") (now EchoStar T1\), which was then, at , the largest and most massive commercial telecommunication satellite ever built at that time until being overtaken by [Telstar 19 Vantage](/wiki/Telstar_19V "Telstar 19V"), at , launched aboard [Falcon 9](/wiki/Falcon_9 "Falcon 9"). The satellite was launched into a lower\-energy orbit than a usual GTO, with its initial apogee at roughly .

On 28 October 2010, an Ariane 5ECA launched [Eutelsat](/wiki/Eutelsat "Eutelsat")'s [W3B](/wiki/Eutelsat_W3B "Eutelsat W3B") (part of its [W Series](/wiki/W_series_%28satellites%29 "W series (satellites)") of satellites) and [Broadcasting Satellite System Corporation](/wiki/Broadcasting_Satellite_System_Corporation "Broadcasting Satellite System Corporation") (B\-SAT)'s [BSAT\-3b](/wiki/BSAT-3b "BSAT-3b") satellites into orbit. But the W3B satellite failed to operate shortly after the successful launch and was written off as a total loss due to an oxidizer leak in the satellite's main propulsion system. The BSAT\-3b satellite, however, is operating normally.

The [VA253](/wiki/Ariane_flight_VA253 "Ariane flight VA253") launch on 15 August 2020 introduced two small changes that increased lift capacity by about ; these were a lighter avionics and guidance\-equipment bay, and modified pressure vents on the payload fairing, which were required for the subsequent launch of the James Webb Space Telescope. It also debuted a location system using [Galileo navigation satellites](/wiki/Galileo_%28satellite_navigation%29 "Galileo (satellite navigation)").

On 25 December 2021, [VA256](/wiki/Ariane_flight_VA256 "Ariane flight VA256") launched the [James Webb Space Telescope](/wiki/James_Webb_Space_Telescope "James Webb Space Telescope") towards a [Sun–Earth L2](/wiki/Lagrange_point%23L2_point "Lagrange point#L2 point") [halo orbit](/wiki/Halo_orbit "Halo orbit"). The precision of trajectory following launch led to fuel savings credited with potentially doubling the lifetime of the telescope by leaving more [hydrazine propellant](/wiki/Hydrazine%23Rocket_fuel "Hydrazine#Rocket fuel") on board for [station\-keeping](/wiki/Orbital_station-keeping%23Lagrange_points "Orbital station-keeping#Lagrange points") than was expected. 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."

### GTO payload weight records

On 22 April 2011, the Ariane 5ECA flight VA\-201 broke a commercial record, lifting [Yahsat 1A](/wiki/Yahsat_1A "Yahsat 1A") and [Intelsat New Dawn](/wiki/New_Dawn_%28satellite%29 "New Dawn (satellite)") with a total payload weight of  to transfer orbit. This record was later broken again during the launch of Ariane 5ECA flight VA\-208 on 2 August 2012, lifting a total of  into the planned geosynchronous transfer orbit, which was broken again 6 months later on flight VA\-212 with  sent towards geosynchronous transfer orbit. In June 2016, the GTO record was raised to , on the first rocket in history that carried a satellite dedicated to financial institutions. The payload record was pushed a further , up to  on 24 August 2016 with the launch of [Intelsat 33e](/wiki/Intelsat_33e "Intelsat 33e") and [Intelsat 36](/wiki/Intelsat_36 "Intelsat 36"). On 1 June 2017, the payload record was broken again to  carrying [ViaSat\-2](/wiki/ViaSat-2 "ViaSat-2") and [Eutelsat\-172B](/wiki/Eutelsat "Eutelsat"). In 2021 VA\-255 put 11,210 kg into GTO.

### VA241 anomaly

On 25 January 2018, an Ariane 5ECA launched [SES\-14](/wiki/SES-14 "SES-14") and [Al Yah 3](/wiki/Al_Yah_Satellite_Communications "Al Yah Satellite Communications") satellites. About 9 minutes and 28 seconds after launch, a telemetry loss occurred between the launch vehicle and the ground controllers. 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, but that their orbital inclinations were incorrect as the guidance systems might have been compromised. Therefore, both satellites conducted orbital procedures, extending commissioning time. SES\-14 needed about 8 weeks longer than planned commissioning time, meaning that entry into service was reported early September instead of July. Nevertheless, SES\-14 is still expected to be able to meet the designed lifetime. This satellite was originally to be launched with more propellant reserve on a [Falcon 9](/wiki/Falcon_9 "Falcon 9") launch vehicle since the Falcon 9, in this specific case, was intended to deploy this satellite into a high inclination orbit that would require more work from the satellite to reach its final geostationary orbit. The Al Yah 3 was also confirmed healthy after more than 12 hours without further statement, and like SES\-14, Al Yah 3's maneuvering plan was also revised to still fulfill the original mission. As of 16 February 2018, Al Yah 3 was approaching the intended geostationary orbit, after series of recovery maneuvers had been performed. The investigation showed that invalid inertial units' azimuth value had sent the vehicle 17° off course but to the intended altitude, they had been programmed for the standard geostationary transfer orbit of 90° when the payloads were intended to be 70° for this supersynchronous transfer orbit mission, 20° off norme. This mission anomaly marked the end of 82nd consecutive success streak since 2003\.


What was found to be wrong with the inertial units' azimuth value?