Successful lift-off of the ill-fated Ariane-5 first test flight
On 4 June 1996, Ariane-5's maiden flight ended in failure, some 40 seconds into the main flight sequence. At an altitude of about 3700 metres, the launcher veered from its correct flight path, broke up and exploded.
Mr Jean-Marie Luton, ESA's Director General, and Mr Alain Bensoussan, CNES's Chairman, immediately set up an independent Inquiry Board, which has now submitted its report.
The report begins by presenting the causes of the failure, analysis of the flight data having indicated:
The chain of events, their inter-relations and causes have been established, starting with the destruction of the launcher and tracing events back in time towards the primary cause. These provide the technical explanations for the failure of flight 501, which lay in the flight control and guidance system. A detailed account is given in the report, which concludes that:
'The failure of Ariane-501 was caused by the complete loss
of guidance and attitude information 37 seconds after start of
the main engine ignition sequence (30 seconds after lift-off).
This loss of information was due to specification and design
errors in the software of the inertial reference system.
The extensive reviews and tests carried out during the Ariane-
5 development programme did not include adequate analysis and
testing of the inertial reference system, or of the complete
flight control system, which could have detected the potential
failure.'
Despite the series of tests and reviews carried out under the programme, in the course of which thousands of corrections were made, shortcomings in the system approach concerning the software resulted in failure to detect the fault. It is stressed that the alignment function of the inertial reference system, which served a purpose only before lift-off (but remained operative afterwards), was not taken into account in the simulations, and that the equipment and system tests were not sufficiently representative.
Without implicating the system architecture, the report makes a series of recommendations for ensuring that the launcher's software operates correctly. The Ariane-5 Programme will be taking action in line with all of these recommendations, as follows:
- correction of the problem in the SRI (inertial reference system) that led to the accident
- re-examination of all software embedded in equipment
- improvement of the representativeness (vis-à-vis the launcher) of the qualification-testing environment
- introduction of overlaps and deliberate redundancy between successive tests:
- improvement and systematisation of the two- way flow of information:
More specifically, the following corrective measures will be applied:
- to the inertial reference system:
- to the system qualification environment:
In addition, the following general measures will be taken:
The ESA Director General and CNES Chairman will be making a joint presentation of the plan of action put into effect and its programmatic consequences at a Press Conference in September.
The 86th Ariane launch (V86) took place successfully on Wednesday 15 May at 22:56 p.m. local time from the Kourou launch base in French Guiana. An Ariane-44L, equipped with four liquid strap-on boosters, placed the Indonesian telecommunications satellite Palapa-C2 and the Israeli telecommunications satellite AMOS into Geostationary Transfer Orbit (GTO).
The 87th Ariane launch took place just four weeks later, at 03:55 a.m. Kourou time on 15 June. This time, an Ariane-44P, equipped with four solid-propellant strap-on boosters, lifted the telecommunications satellite Intelsat-709 into GTO for the International Telecommunications Satellite Organisation (Intelsat).
Just over three weeks later, at 19:24 p.m. local time on 9 July, the next Ariane launch (V89) was underway. On this occasion, another Ariane-44L placed two telecommunications satellites, Turksat-1C and Arabsat-2A, into GTO.
The latest Ariane-4 launch (V90), carrying the telecommunications satellites Telecom-2D and Italsat-F2, took place on 8 August at 19:49 p.m. local time.
ESA, the European Commission and the European Organisation for the Safety of Air Navigation (EuroControl) are jointly developing EGNOS (European Geostationary Navigation Overlay Service). This European augmentation system for satellite navigation will provide civil GPS (Global Positioning System) and GLONASS (Russian satellite navigation system) users on land, at sea or in the air with improved accuracy, integrity and service availability.
Working together, the three entities are known as the European Tripartite Group (ETG). On 27 June, the ETG signed leases for the first two navigation transponders that will be used to broadcast EGNOS signals to users. These transponders are being flown by two Inmarsat-III satellites, located at longitudes of 64 deg East (Indian Ocean Region) and 15.5 deg West (Atlantic Ocean Region - East). Together they will cover not only the whole of Europe, but Africa, South America and most of Asia also. The Indian-Ocean satellite has been operational since 12 May 1996, and the Atlantic-Ocean satellite is scheduled for launch in August 1996. The leases were signed, in the presence of the European Commission, EuroControl and Inmarsat, by ESA, France Telecom and Deutsche Telekom, the two European signatories of the Inmarsat operating agreement which had submitted the EGNOS proposal to the Inmarsat Council. These leases run for five years, with the possibility of an extension for a further five years.
In its final set-up, EGNOS will provide Ranging, Integrity and Wide Area Differential Services:
The Ranging Service is planned to start in 1997. The other services will be phased in gradually between 1998 and 2000.
EGNOS itself will be composed of:
The contract for the development of the ranging function was awarded to the French company Thomson-CSF in July 1995. In December 1995, the same company was awarded another contract for the detailed design of the entire EGNOS infrastructure. A proposal for subsequent EGNOS development, system verification and testing will be submitted in the second half of 1996.
Within the ETG, ESA is responsible for the management of all development, deployment and technical-validation activities; EuroControl provides the civil-aviation user requirements and supports the certification process, while the European Commission consolidates all user requirements and oversees development of the EGNOS receivers and associated standardisation activities and trials, and supports access to the Inmarsat-III navigation transponders.
Mr John Manley, Canadian Minister for Industry, and Mr Jean- Marie Luton, ESA's Director General, met in Ottawa on 10 July, in the presence of Mr W. Mac Evans, President of the Canadian Space Agency (CSA), to discuss current and future relations between Canada and ESA.
During the meeting, Mr Luton and Mr Mac Evans signed two Agreements on participation by Canada in two ESA programmes: the General Support Technology Programme (GSTP), and the Advanced Research in Telecommunications Systems Programme (ARTES). The Canadian contributions to these programmes will amount to some 8 million Accounting Units (15 million Canadian dollars) and will enable European and Canadian industry to cooperate in future in critical high-technology areas such as remote-sensing and satellite communications.
'Today, we are making an investment in Canada's scientific, technical and industrial future which will have far-reaching benefits', said Mr Mac Evans. 'Industrial contracts and strategic alliances with key European space companies are some of the principal economic benefits this strategic investment provides'. Mr Manley also stressed '...the value of Canada's partnership with ESA, our second largest space partner. These agreements further cement a long-standing relationship that has resulted in economic benefits for Canadian industry'.
Canada has been an ESA Cooperating State since 1979, and is currently the only non-European country participating directly in ESA programmes.
From right to left seated: Mr W Mac Evans and Mr Jean-Marie
Luton; standing: Ms Diana Durnford (Special Assistant to the
Minister), Mr John Manley and Mr Karl-Egon Reuter (Head of the
ESA Cabinet).
An Agreement between ESA the German Space Agency (DARA) was signed on 30 June by Mr René Collette, Director of ESA's Telecommunications Programme, and Mr Jan-Baldem Mennicken, Director General of DARA. It concerns the provision of observation instruments for the new ground station at Izana (Tenerife, Spain), which was inaugurated the same day in the presence of the King and Queen of Spain.
Germany has supplied a 1-m Zeiss-Jena telescope, the dome for the building, and associated equipment to be used for the testing, calibration and operation of optical communications payloads flown on ESA's Artemis satellite, and for the observation of space debris.
The essential roles of the Izana station, operated under an Agreement between ESA and the Instituto de Astrofisica de Canarias (IAC), apart from astronomical observations, include the receipt of laser signals from data-relay satellites and the observation/tracking of space debris. The space-debris work will be conducted by the IAC, DARA and ESA's European Space Operations Centre in Darmstadt (Germany).
Mr René Collette (seated, left) and Mr Jan-Baldem
Mennicken (seated, right) at the Tenerife signing
Mr René Collette (left) greets Queen Sophia and King
Juan Carlos
In the foreground, the observatory building (carrying the
German dome) that will house the new instrumentation
Hugo Ragnar Parr, currently Director General of the Research Department at the Norwegian Ministry of Industry and Energy, will be Chairman of the ESA Council for the next two years. Mr Parr was unanimously elected at the Council's 125th Meeting in Paris on 25/26 June 1996. He takes over from Mr Pieter-Gaele Winters of The Netherlands, whose term of office ended on 30 June 1996.
Hugo Parr, born on 23 April 1947, holds a Degree in Physics from the University of Washington (1969) and a Doctorate in Solid-State Physics from the University of Oslo (1976). He has been a member of the ESA Council since 1995.
Mr H.R. Parr
n 8 August, seven years to the day after the Hipparcos satellite's launch, and just three years after the end of satellite operations, ESA and the Hipparcos Science Team have announced the completion of the Hipparcos and Tycho Stellar Catalogues. The difficult but astrophysically extremely important task of measuring stellar distances and motions has been completely revolutionised by this highly successful ESA science mission, which has totally surpassed all of the scientific goals motivating its acceptance as an ESA project in 1980.
The finalisation of these unique and highly complex stellar Catalogues has been completed almost exactly according the schedule predicted before launch for the Hipparcos Catalogue, and about a year in advance of the pre-launch prediction for the Tycho Catalogue. ESA acknowledges the intensive and sustained effort by the many Hipparcos consortia scientists involved in the Catalogue preparation and finalisation tasks under the scientific consortia leaders Prof. Erik Hoeg (Copenhagen), Prof. Jean Kovalevsky (OCA, CERGA), Dr Lennart Lindegren (Lund), and Dr Catherine Turon (Meudon).
With the Hipparcos and Tycho Catalogues finalised, the first phase of the Hipparcos data release (concerning proposals made by members of the scientific consortia) was initiated in August. The release of data to 1982 proposers will take place later in the year or early in January 1997.
Measurement period 1989.85 1993.21 Catalogue epoch J1991.25 Reference system ICRS Coincidence with respect to ICRS (all three axes) ± 0.6 milliarcsec (mas) Proper motion deviationfrominertial (all three axes) ± 0.25 mas/yr Estimated systematic errors in astrometry <0.1 mas Hipparcos Catalogue Number of entries 118 218 Mean sky density ~3/deg² Limiting magnitude V ~712.4 mag Completeness Up to V=7.3-9.0 mag Median precision of positions, J1991.25 (Hp<9 mag) 0.70 mas Median precision of parallaxes (Hp<9 mag) 0.97 mas Median precision of proper motions (Hp<9 mag) 0.80 mas/yr 10% (each of the five parameters) better than 0.47-0.66 mas Smallest errors on the five astrometric parameters 0.27-0.38 mas Distance determined to better than 10% 20 853 stars Distance determined to better than 20% 49 399 stars Median photometric precision (Hp, for Hp<9 mag) 0.0015 mag Number of entries variable or possibly variable 11 597 (8237 new) Number of solved or suspected double/multiple systems 23 882 Tycho Catalogue Number of entries 1 058 332 Mean sky density ~25/deg² Limiting magnitude V T ~11.5 mag Completeness V T ~10.5 mag Median astrometric precision (all stars), J1991.25 25 mas Median astrometric precision (V T <9 mag), J1991.25 7 mas Inferred ratio of external errors to standard errors ~1.0-1.2 Systematic errors in astrometry < 1 mas Median photometric precision (V T <9 mag) 0.01-0.02 mag
ESA's largest satellite is currently being tested at the European Space Research and Technology Centre (ESTEC) in Noordwijk (NL). The 10 m-high structural model of the Polar Platform has been undergoing tests in the Large European Acoustic Facility (LEAF), and modal survey testing (to identify the spacecraft's natural modes of vibration) is presently in progress.
The Polar Platform, which forms the basic carrier structure for the Envisat-1 payload complement, weighs 8 tons and will be launched by an Ariane-5 vehicle in 1999. Prior to launch, the flight unit of this very large Earth-observation spacecraft will also be at ESTEC for a seven-month test campaign during 1998.
The structural model is scheduled to undergo an extensive sequence of tests in the various specialised facilities at ESTEC and will therefore remain in Noordwijk until almost the end of the year. In October/ November, it will be the first 'customer' to use ESTEC's new Hydraulic Vibration Test Facility (HYDRA), which is presently in its final phase of construction.
The Agency has learned with regret of the death, on 7 August 1996 in Bonn Bad Godesberg, of Dr Alexander Hocker, former Director General of ESRO. Born in Schweinsburg, Germany on 29 April 1913, Alexander Hocker read law, political science and economics at the Universities of Innsbruck, Hamburg and Leipzig, before gaining his Doctorate from the Faculty of Law at Leipzig.
He became involved with ESRO from its earliest days, through his work with the Legal, Administrative and Financial Working Group of COPERS, which he chaired from 1961 until 1964. In 1964, he was appointed Vice Chairman of the ESRO Council, taking over the Chairmanship for the years 1965-1967. In February 1971, he was appointed Director General of ESRO for a three-year term, which was subsequently extended until 30 June 1974.
During his mandate as Director General, Alexander Hocker guided ESRO through a succession of important events in its history, including:
He will be remembered for these and his many other endeavours which played a pivotal role in shaping the futures of both ESRO and ESA.
Dr. A. Hocker
ESA astronaut Jean-François Clervoy has been named by NASA as one of the six crew who will conduct the sixth scheduled docking of the US Space Shuttle 'Atlantis' with the Russian space-station Mir. This mission (STS-84), scheduled for May 1997, is part of NASA's Phase-One Program for the International Space Station.
Jean-François Clervoy, of French nationality, will serve as a Mission Specialist on the trip. The other five crew members, all NASA astronauts, will be: Charles Precourt (Commander), Eileen Collins (Pilot), and Carlos Noriega, Edward Lu and Mike Foale (all Mission Specialists).
The Space Shuttle, carrying the Spacehab double module, will remain docked to Mir for five days. During that time, supplies will be transferred to the station and samples and data from completed experiments will be stowed on the Shuttle for return to Earth.
It will be the second flight for Jean-François, who flew previously on STS-66, the Third Atmospheric Laboratory for Applications and Science (ATLAS-3), in November 1994. He joined ESA's Astronaut Corps, based at the European Astronauts Centre (EAC) in Cologne, Germany, in May 1992. After completing his introductory astronaut training programme at EAC, he entered NASA's Mission Specialist training programme at Johnson Spaceflight Center (JSC) in Houston and was part of the first international astronaut class, which graduated in August 1993.
Jean-François Clervoy
When Space Shuttle 'Columbia' (STS-78) lifted off from Kennedy Space Center on 20 June, ESA had five major facilities on board and responsibility for more than half of the experiments to be conducted on this multi-discipline Life and Microgravity Sciences Spacelab Mission (LMS).
The STS-78 crew members and their alternates, during pre-mission training
The key objectives of the 16-day LMS mission were to study the effects of microgravity on the physiology, development and behaviour of living systems, and to conduct experiments in fluid physics, materials processing and the growth of protein crystals. Spacelab, developed and funded by ESA as Europe's contribution to NASA's Space Transportation System, provides astronauts with an ideal laboratory-like environment in which to conduct such research.
ESA-developed experiment and research facilities for this mission included the Bubble, Drob and Particle Unit (BDPU), the Advanced Protein Crystallisation Facility (APCF), the Advanced Gradient Heating Facility (AGHF) and the Torque Velocity Dynamometer. The ESA facilities and experiments involved scientists from 10 countries, with Principal Investigators from Belgium, Canada, France, Germany, Italy, Spain, Sweden, Switzerland, the United Kingdom and the United States. The international Shuttle crew included Canadian astronaut Robert Thirsk and the French astronaut Jean-Jacques Favier as payload specialists. ESA astronaut Pedro Duque from Spain served as a ground crew communicator during the mission.
ESA Bulletin Nr. 87.