Ariane 5 Ariane 5 is a European heavy-lift space launch vehicle developed and operated by Arianespace for the European Space Agency (ESA). It is launched from the Centre Spatial Guyanais (CSG) in French Guiana. It has been used to deliver payloads int ...

Guiana Space Centre The Guiana Space Centre (french: links=no, Centre spatial guyanais; CSG), also called Europe's Spaceport, is a European spaceport to the northwest of Kourou in French Guiana, a region of France in South America. Kourou is located approximatel ...

SYLDA Sylda is a village and a former municipality in the Mansfeld-Südharz district, Saxony-Anhalt, Germany. Since 1 January 2010, it is part of the town Arnstein.

SES-14

SES-14 SES-14 is a geostationary communications satellite operated by SES S.A. at 47.5° West, replaces NSS-806, and designed and manufactured by Airbus Defence and Space. The satellite launched on 25 January 2018 at 22:20 UTC along with the Global-sc ...

, built by

Airbus Defence and Space Airbus Defence and Space is the division of Airbus SE responsible for the development and manufacturing of the corporation's defence and space products, while also providing related services. The division was formed in January 2014 during the ...

in

Toulouse Toulouse ( , ; oc, Tolosa ) is the prefecture of the French department of Haute-Garonne and of the larger region of Occitania. The city is on the banks of the River Garonne, from the Mediterranean Sea, from the Atlantic Ocean and from Par ...

,

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

for

SES SES, S.E.S., Ses and similar variants can refere to: Business and economics * Socioeconomic status * Scottish Economic Society, a learned society in Scotland * SES, callsign of the TV station SES/RTS (Mount Gambier, South Australia) * SES S.A., ...

of

Luxembourg Luxembourg ( ; lb, Lëtzebuerg ; french: link=no, Luxembourg; german: link=no, Luxemburg), officially the Grand Duchy of Luxembourg, ; french: link=no, Grand-Duché de Luxembourg ; german: link=no, Großherzogtum Luxemburg is a small lan ...

, was in the upper position. It had a mass at liftoff of , hosting the

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

-funded

GOLD Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

payload. SES-14 was the second satellite based on

Airbus Airbus SE (; ; ; ) is a European Multinational corporation, multinational aerospace corporation. Airbus designs, manufactures and sells civil and military aerospace manufacturer, aerospace products worldwide and manufactures aircraft througho ...

's Eurostar E3000 EOR

satellite bus A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held. Bus-derived satellites are opposed to specially produced satellites. Bus-d ...

to be launched by

Arianespace Arianespace SA is a French company founded in 1980 as the world's first commercial launch service provider. It undertakes the operation and marketing of the Ariane programme. The company offers a number of different launch vehicles: the heavy ...

.

Al Yah 3

Al Yah 3 Al Yah Satellite Communications Company P.J.S.C. (Yahsat) is a public company listed on thAbu Dhabi Securities Exchange (ADX)and a subsidiary of Mubadala Investment Company, Mubadala Investment Company PJSC, offering multi-mission satellite service ...

, built by

Orbital ATK Northrop Grumman Innovation Systems (NGIS) was a sector (business segment) of Northrop Grumman from 2018 through 2019. It was formed from Orbital ATK Inc. a company which resulted from the merger of Orbital Sciences Corporation and parts of Alli ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

for

Yahsat Al Yah Satellite Communications Company P.J.S.C. (Yahsat) is a public company listed on thAbu Dhabi Securities Exchange (ADX)and a subsidiary of Mubadala Investment Company PJSC, offering multi-mission satellite services in more than 150 countries ...

of the

United Arab Emirates The United Arab Emirates (UAE; ar, اَلْإِمَارَات الْعَرَبِيَة الْمُتَحِدَة ), or simply the Emirates ( ar, الِْإمَارَات ), is a country in Western Asia (The Middle East). It is located at th ...

, was in the lower position. It had a mass at liftoff of . Al Yah 3 was the first satellite based on Orbital ATK's

GEOStar-3 The GEOStar-3 is a communications satellite spacecraft model made by Northrop Grumman Innovation Systems. GEOStar-3 represents an evolutionary growth from Northrop Grumman Innovation Systems GEOStar-2 platform. GEOStar-3 Bus can accommodate pa ...

satellite bus to be launched by Arianespace.

Mission description

Launch date

The

Ariane 5 Ariane 5 is a European heavy-lift space launch vehicle developed and operated by Arianespace for the European Space Agency (ESA). It is launched from the Centre Spatial Guyanais (CSG) in French Guiana. It has been used to deliver payloads int ...

launch ( of 2018) was planned to take place within a launch window of 45 minutes starting on 25 January 2018 at 22:20 UTC (19:20 local time). The launcher engines effectively were ignited at the very beginning of that window, from Ariane Launch Complex No. 3 (

ELA-3 ELA-3 (french: Ensemble de Lancement Ariane 3, lit=Ariane Launch Complex 3), is a launch pad and associated facilities at the Centre Spatial Guyanais in French Guiana. ELA-3 is operated by Arianespace as part of the expendable launch system f ...

) in

Kourou Kourou () is a commune in French Guiana, an overseas region and department of France in South America. Kourou is famous for being the location of the Guiana Space Centre, the main spaceport of France and the European Space Agency (ESA). It i ...

,

French Guiana French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas departments and regions of France, overseas department/region and single territorial collectivity of France on the northern Atlantic ...

.

Orbit

The mission was planned to last 35 minutes and 7 seconds, placing both satellites into a super-synchronous transfer orbit, with an

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

of about and a

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

of about , at an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of about 3°.

Countdown and flight sequence

The planned sequence was as follows:

Anomaly

The telemetry of the launcher was lost from about 9 minutes to 9 minutes and 30 seconds (the uncertainty being due to the fact that the data as displayed in real-time may have been extrapolated for a finite amount of time) into the flight, close to the moment when the main stage (EPC) separation and upper stage (ESC-A) ignition should have occurred.http://www.arianespace.com/wp-content/uploads/2018/01/VA241-launchkit-EN2.pdf VA241 Launch Kit Then about 1 hour after liftoff,

Arianespace Arianespace SA is a French company founded in 1980 as the world's first commercial launch service provider. It undertakes the operation and marketing of the Ariane programme. The company offers a number of different launch vehicles: the heavy ...

's CEO and chairman

Stéphane Israël Stéphane Israël (born 3 January 1971) is a senior French civil servant. He was a magistrate at the Court of Audit, chief of staff at the French Minister of Economics, Arnaud Montebourg; worked in the aeronautics industry at Astrium, a subsidiary ...

made a quick speech saying that the launcher suffered an anomaly. His statement in front of the VIP audience in the Jupiter control room was: :"Ladies and gentlemen, so I come to give you some information because we have had an anomaly on this launch. Indeed, we lost contact with the launcher a few seconds after the ignition of the upper stage. At that time, we can consider that the upper composite and the satellite have been ''satellised'' 'sic'': bad translation of French ''satellisés'', meaning put in orbit">sic.html" ;"title="'sic">'sic'': bad translation of French ''satellisés'', meaning put in orbit But as I said, we lost contact. So up to now, our customers do not have contact with the satellite We need now some time to know if they ''have been'' separated 'sic''], and where they are exactly, to better analyse the consequences of this anomaly. I want to present my deepest excuses to our customers, who have entrusted us one more time. We know that there is no launch with no risk. We know that launch is always difficult, and tonight Ariane 5 has had an anomaly, so let's take time now to better understand the situation of the satellite Arianespace, in full transparency, will come back to you to provide you with some more information as soon as we have them. I apologise on behalf of Arianespace".https://www.youtube.com/watch?v=g47aftHgOnk&t=10m7s Replay of the Arianespace live video flux. Later in the night,

Arianespace Arianespace SA is a French company founded in 1980 as the world's first commercial launch service provider. It undertakes the operation and marketing of the Ariane programme. The company offers a number of different launch vehicles: the heavy ...

issued a first press release http://www.arianespace.com/wp-content/uploads/2018/01/CDP-18-05-VA241-update-FR.pdf First press release by Arianespace ''(in French)'' mentioning that the Natal tracking station did not acquire telemetry of the launcher, which lasted until the end of the mission, and that the separation of both payloads was confirmed, together with their successful injection into Earth orbit and the link acquisition by both customers. On the same day, Arianespace issued a second press releasehttp://www.arianespace.com/wp-content/uploads/2018/01/1-26-2018-VA241-Ariane5-a-mis-en-orbite-SES14-AlYah3-FR.pdf Second press release by Arianespace (''in French'') stating that SES and YahSat confirmed the acquisition and good health of the two satellites despite a deviation of their trajectory. It was also stated that the telemetry was lost by the tracking stations 9 minutes and 26 seconds after reference time ''T'', due to a deviation of the trajectory. On 26 January 2018, SES informed on their website that while its satellite is in good health it would require to "set up a new orbit raising plan", and that it would thus "reach the geostationary orbit only four weeks later than originally planned", indicating that the satellites were not delivered to the intended super-synchronous transfer orbit (with an

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

of 45,000 km and

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 3°) by the launch vehicle. This was confirmed later that day when the orbital elements of the satellites were released, revealing that the deployment orbit's apogee had a minor deviation of about 2,000 km while the inclination suffered a significant deviation of almost 18° from intended. The flight path anomaly became obvious when initial analysis showed that the launch azimuth had gone wrong since the very beginning of the flight, during the first stage firing, with unexpected slow roll manoeuvre just after liftoff. In standard Ariane 5 launch, the roll maneuvre should only begin around 17 seconds after reference time ''T'' or 10 seconds after liftoff. The anomaly might have been due to a

human error Human error refers to something having been done that was " not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits".Senders, J.W. and Moray, N.P. (1991) Human ...

during the programming of the Guidance, Navigation and Control (GNC) combined with a failed verification procedure according to early developments as the launch team reported not to have double-checked the guidance computer parameters to reduce workload duplication, even though double-checking them played the vital role in the rocket's reliability. But Arianespace and ArianeGroup issued a statement insisting that all the control processes remain unchanged, while they restructured the organization now directly from ArianeGroup, affecting the launch team now with many of ArianeGroup engineers.

Frédérique Vidal Frédérique Vidal (born 9 May 1964) is a Monegasque-born French-based biochemist, academic administrator, and politician who served as Minister of Higher Education, Research and Innovation in the government of Prime Ministers Édouard Philippe a ...

, Minister of Higher Education, Research and Innovation, said that the rocket did not overfly

Kourou Kourou () is a commune in French Guiana, an overseas region and department of France in South America. Kourou is famous for being the location of the Guiana Space Centre, the main spaceport of France and the European Space Agency (ESA). It i ...

, but for the first time flew very close to the city of Kourou. In standard launch of any rocket it should have been immediately destroyed by either

Range Safety Officer In the field of rocketry, range safety may be assured by a system which is intended to protect people and assets on both the rocket range and downrange in cases when a launch vehicle might endanger them. For a rocket deemed to be ''off course'' ...

or its onboard Autonomous Flight Termination System once the rocket flew off course. But at the point when the Range Safety Officer for this mission wanted to destroy the rocket, it was too late as it already overflew close to the city of Kourou, so destroying the rocket would have been potentially more dangerous with the debris raining down over Kourou than continuing flight.

Aftermath

An independent investigation board was established in collaboration with the

European Space Agency , owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (1205 ...

(ESA) and National Aeronautics and Space Administration (

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

), under the chairmanship of ESA's inspector general to investigate what caused the trajectory deviation during flight. The conclusions of the investigation commission led by ESA's inspector general, Toni Tolker-Nielsen, were released on 22 February 2018, indicating that engineers left the inertial navigation units' azimuth value at 90° (the standard for

geostationary transfer orbit A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a type of geocentric orbit. Satellite, Satellites that are destined for geosynchronous orbit, geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into ...

(GTO) launch on Ariane 5), however unusually 70° was intended for these payloads riding into unusual supersynchronous transfer orbit (GTO), explaining the cause of the 17° trajectory deviation. Standard verification procedure missed the azimuth data. The reason of launching both satellites to SSGTO was Al Yah 3 satellite manufacturer ( Orbital-ATK) abruptly requested Arianespace to change the target orbit profile to SSGTO in order to release the Al Yah 3 satellite at a right angle relative to the direction of motion of the launch vehicle. Both satellites have now conducted orbital make-up procedure by changing their maneuvering plan, which would extend commissioning time. SES-14 needed about 4 weeks longer than planned commissioning time, meaning that entry into service now expected in August instead of July. Nevertheless, SES-14 is still expected to be able to meet the designed life time, since it was originally to be launched on the

Falcon 9 Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX. The rocket has two stages. The first (booster) stage carries the second stage and payl ...

launch vehicle which would have required more propellant reserves as Falcon 9 usually deploys geostationary satellites into a high inclination orbit that requires more propellant to approach into final geostationary orbit. SES informed

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

that they expect no effect on the quality of observations and data of the agency's Global-scale Observations of the Limb and Disk (GOLD) instrument after the launch anomaly. 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 30 May 2018, Al Yah 3 had arrived to the intended geostationary orbit, after series of recovery maneuvers had been performed and completed its in-orbit testing. Al Yah 3 is expected to enter into service around July 2018, at the start of new Eutelsat's fiscal year. Due to excess propellant usage during recovery, Al Yah 3's operational life was reduced to approximately 9 years. Yahsat was expected to receive up to 50% of its insured value (~US$108 million) in damages. This mission anomaly ended the 82 consecutive launch success streak from 2003.

References

External links

Ariane Flight VA241 (Arianespace website)
{{Ariane VA241, Ariane flight 2018 in spaceflight 2018 in French Guiana January 2018 events in South America Rocket launches in 2018

Payload

SES-14

Al Yah 3

Mission description

Launch date

Orbit

Countdown and flight sequence

Anomaly

Aftermath

References

External links