Publication archive

Publication archive

ISO, the Infrared Space Observatory, will provide astronomer's with an unprecedented opportunity - and the only one for the next 10 years - to make scientific observations of weak infrared radiation sources. The development of the Observatory proved to be a challenging task: there was little available experience with the advanced technologies required for such a new infrared-astronomy mission. The scientific instruments were developed by groups of scientific institutes and industry under national funding. The satellite was developed, manufactured, integrated and tested by an industrial consortium made up of 32 companies, mostly from Europe. ESA is performing the flight operations. The USA and Japan are also contributing to the mission in return for observation time.
Published: 01 November 1995
he payload of ESA's Infrared Space Observatory (ISO) consists of four scientific instruments: a camera (ISOCAM), an imaging photo-polarimeter (ISOPHOT), a long-wavelength spectrometer (LWS), and a short-wavelength spectrometer (SWS). Each of these instruments was built by an international consortium of scientific institutes using national funding. ESA was responsible for their subsequent integration into the ISO spacecraft and will carry out the in-orbit operations.
Published: 01 November 1995
ESA's Infrared Space Observatory (ISO) consists of two modules: the Payload module, which includes the telescope and the scientific instruments, and the Service Module, which houses the instruments electronics, the hydrazine propellant tank and all other classical spacecraft subsystems. To ensure that the telescope is kept near absolute zero and thus is the least disturbed by the effects of the infrared emissions from other elements of the system, the telescope is enclosed in a helium-cooled cryostat. The cryostat in turn is shaded by a Sun-shield to protect it from the heat of the direct Sun. The shield has a covering of solar cells that provide the electrical power needed for the mission.
Published: 01 November 1995
The Infrared Space Observatory (ISO) satellite will be the world's first true astronomical observatory in space operating at infrared wavelengths. Astronomers will be able to choose specific targets in the sky and point ISO towards them for up to ten hours at a time to make observations with versatile instruments of unprecedented sensitivity. During its lifetime of 18 months, ISO will be used to observe all classes of astronomical objects ranging from planets and comets in our own solar system, right out to the most distant galaxies.
Published: 01 November 1995
The roots of the SOHO mission and the story leading to the comprehensive observatory that the spacecraft is today are summarised here. Now fully operational in its halo orbit around the first Lagrangian point (L1) between the Earth and the Sun, SOHO is providing the international scientific community with the unique opportunity, and also challenge, of understanding the Sun and heliosphere as one complex, global system. It is a superb tool with which to investigate our daylight star and its circumstellar environment, from the Sun's centre, through its visible surface and tenuous corona, and out into the heliosphere to distances corresponding to more than ten times the orbital distance of the Earth.
Published: 02 April 1996
ESA's Infrared Space Observatory (ISO) was successfully launched from the Guiana Space Centre in Kourou on 17 November 1995. Its requirements in terms of ground-segment preparation were particularly demanding due to the limited mission lifetime, which calls for highly efficient operations, the very fast pace of the ISO observations, some lasting just a few minutes, the severe pointing requirements which demand sophisticated planning, and the real-time commanding of the highly sophisticated payload of four instruments with multiple operating modes from a computer- generated, automatically executing file. It was recognised that, given these demanding constraints, a well thought out approach to overall ground-segment integration, testing and validation would be required to ensure success. The approach that was chosen, based on the concept of end-to-end testing supported by sophisticated instrument simulators, proved highly effective. As a result, the ISO ground segment was ready to support all of the mission's operational phases in time for the spacecraft's launch.
Published: 02 April 1996
This article gives a summary of the early in-orbit performance of the Agency's recently launched Infrared Space Observatory (ISO) spacecraft and its instruments and presents some of the initial scientific results.
Published: 02 April 1996
The Cluster mission will be operated from ESOC. In addition to the mission challenges imposed by the simultaneous operation of four co-ordinated spacecraft, ESOC will be responsible for maintaining the software of the On-Board Data Handling (OBDH) subsystem from the time of launch until the end of the mission, which is nominally two and a half years. This on-board software maintenance capability provides a powerful means of adapting the behaviours of the four Cluster spacecraft to the real-time status of the hardware of each and to any operational difficulties that they might encounter during their operating lifetimes.
Published: 02 July 1997
The Cluster mission is designed to study the small-scale structures that are believed to be fundamental in determining the key interaction processes in cosmic plasma. The mission will be controlled from ESOC, which will also be responsible for commanding the scientific payloads of the four spacecraft, in collaboration with the Cluster Principal Investigators (PIs), and for collecting and distributing the mission results to the scientific community. To support the Cluster mission operations, ESOC has developed the Cluster Data Processing System (CDPS), the architecture of which is based on three main components.
Published: 02 July 1997
The Cluster mission was first proposed to the Agency in late 1982 and was subsequently selected, together with SOHO, as the Solar Terrestrial Science Programme (STSP), the first Cornerstone of ESA's Horizon 2000 Programme. This article gives an overview of the complex chain of events that have taken place between the loss of the original mission with the Ariane-5 launch failure and the recent approval of the recovery mission known as Cluster-II.
Published: 02 July 1997
Huygens is being carried as a passenger on NASA's Cassini Orbiter to Saturn, where it will be released to enter the atmosphere of Titan, the planet's largest moon. During the controlled descent phase, its instruments will execute a complex sequence of measurements to study the atmosphere's chemical and physical properties and, if it survives impact, Huygens will collect data on Titan's surface properties. Flight operations will be conducted from the Huygens Probe Operations Centre (HPOC) at ESOC. This article describes the ground-system infrastructure, procedures and constraints involved in operating Huygens over its 6.7-year mission lifetime.
Published: 01 November 1997
Many engineering challenges had to be overcome in designing the first probe planned to study a moon beyond the Earth's system. An extensive development programme was undertaken, involving several unusual tests, driven by the mission's unique aspects. ESA's Huygens Probe will be delivered to Titan, Saturn's largest satellite, by the Cassini Orbiter in 2004. After a dormant interplanetary journey of 6.7 years - although Huygens will be activated every 6 months for health checks - its aeroshell will decelerate it in less than 3 min from the entry speed of 6 kms-1 to 400 ms-1 (Mach 1.5) by about 160 km altitude. From that point, a pre-programmed sequence will trigger parachute deployment and heat-shield ejection. The main scientific mission can then begin, lasting for the whole of the Probe's 2-2.5 h descent.
Published: 01 November 1997
The Huygens Probe is ESA's element of the joint Cassini/Huygens mission with NASA to the Saturnian system. Huygens will be carried on NASA's Cassini Orbiter to Saturn, where it will be released to enter the atmosphere of Titan, the planet's largest satellite. The Probe's primary scientific phase occurs during the 2-2.5 h parachute descent, when the six onboard instruments execute a complex series of measurements to study the atmosphere's chemical and physical properties. Measurements will also be conducted during the 3 min entry phase, and possibly on Titan's surface if Huygens survives impact. This article provides an overview of the mission and a concise description of the payload.
Published: 01 November 1997
Direct evidence of the constitution of cometary volatiles is particularly difficult to obtain, as the constituents observable from Earth and even during the flybys of Comet Halley in 1986, result from physico-chemical processes such as sublimation and interactions with solar radiation and the solar wind. What we know today about cometary material from those earlier missions and ground-based observations does, however, demonstrate the low degree of evolution of cometary material and hence its tremendous potential for providing us with unique information about the make up and early evolution of the solar nebula.
Published: 01 February 1998
Definition of the Rosetta ground segment began in 1996 and it soon became clear that a common checkout and mission-control system would be very beneficial for the mission. The chosen approach for achieving this goal was to develop building blocks for the Central Checkout System that can be re-utilised later in the development of the Flight Control System. The Rosetta prime contractor and AIV contractor fully endorsed this approach and the complete system is currently under development. The first delivery of the database system should take place in November 1998, followed by that of the first Central Checkout System in 1999.
Published: 02 April 1998
The XMM (X-ray Multi-Mirror) spacecraft, a space-borne X-ray observatory to be launched by Ariane-5 in 1999, stands 10 m-high and measures over 4 m in diameter in launch configuration, for a launch mass of just under 4 tonnes. Such a tall spacecraft challenges the capabilities of existing European environmental testing facilities. The spacecraft design does allow for a relatively straightforward splitting into modules. The Structural and Thermal Model (STM) of the XMM spacecraft has successfully undergone mechanical environmental testing at the European Space Research & Technology Centre (ESTEC). This article briefly introduces the XMM project, presents an overview of the XMM configuration constraints, explains the spacecraft-level model philosophy and mechanical test flow, and summarises the present status of the tests performed.
Published: 02 April 1998
The Infrared Space Observatory (ISO), the world's first true orbiting infrared observatory, was switched off in May 1998, long after the expiry date foreseen in the specifications for the mission. Instead of the required 18 months, the highly-successful in-orbit operations of this excellent satellite continued for more than 28 months leading to an extensive database of observations which will be providing astronomical surprises for years to come. This article looks back at the way operations were conducted.
Published: 02 July 1998
The Rosetta mission is designed to study in-situ a cometary nucleus' environment and its evolution in the inner Solar System. To be launched in January 2003 by an Ariane-5, Rosetta will rendezvous with Comet P/Wirtanen in 2011, after one Mars- and two Earth-gravity assists, and two asteroid fly-bys. The near-comet operations, which are scheduled to last about 1.5 years, will require a minimum return-link telemetry data rate of 5 kbit/s to meet the scientific goals, with about 14 hours of daily coverage.
Published: 02 July 1998
The SMART-1 mission, to be launched at the end of 2001, is intended to demonstrate innovative and key technologies for deep-space scientific missions. Its use, for example, of solar electric propulsion as its primary drive mechanism will be a first for Europe and is essential in paving the way for future ESA projects with large velocity requirements, such as the Mercury Cornerstone mission. SMART-1 will also be a test case for a new approach in terms of implementation strategy and spacecraft procurement for the ESA Science Programme. The total life-cost budget allocated to SMART-1 is 50 MECU. This budget constraint imposes use of a cheap launch option, such as an Ariane-5 auxiliary payload launch into a standard GTO or a Rockot escape-trajectory launch. This in turn limits the planetary bodies that can be reached within a given short (1.5 - 2 year) overall mission lifetime, which do, however, include the Moon and Earth-crossing asteroids or comets.
Published: 02 July 1998
Mars Express, planned to be the first 'flexible mission' in the revised ESA Long-Term Scientific Programme, is based on a fast implementation scenario and will be launched towards Mars in June 2003 by a Soyuz/Fregat launcher. The mission is cost-capped at 150 MECU and will be submitted for approval by ESA's Science Programme Committee in November 1998. Its payload has already been selected and European industry will submit bids for design and development phases (Phases-B/C and D) at the beginning of September 1998.
Published: 02 July 1998
31-Oct-2020 07:54 UT

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