Foreword to European Space Directory 2015

On 20 January 2014, ESA’s comet-chasing Rosetta spacecraft woke up from 957 days in deep-space hibernation.

ESA’s European Space Operations Centre in Darmstadt, Germany, was the place where we all could "see" it happen. Since its launch from Europe’s Spaceport in Kourou on 2 March 2004, Rosetta had travelled to a distance of some 800 million kilometres from the Sun and close to the orbit of Jupiter, passing by Earth three times and Mars once, and flying past two asteroids. It then closed in on its destination, Comet 67P/Churyumov-Gerasimenko, moving farther into the inner Solar System. For the most distant part of the journey, the spacecraft was put into deep-space hibernation. The spacecraft’s internal alarm clock was set for wake-up at 10:00 GMT on 20 January, and the first signal from the awakened spacecraft reached Mission Control at 18:18 GMT.

In March, ESA astronaut Thomas Pesquet was assigned to a long-duration mission to the International Space Station in 2016. With Thomas Pesquet’s assignment, all six ESA astronauts from the class of 2009 will have flown to the Station on missions within seven years of graduation. During Thomas’ mission, an atomic clock will be installed on the Station to connect with other atomic clocks on Earth to test Einstein’s theory of relativity and allow even more accurate world timekeeping. The results could double the accuracy of satellite navigation, allowing us to pinpoint our location on Earth with even higher precision. 

ESA and CERN, the European Organization for Nuclear Research, signed a cooperation agreement on 28 March to foster future collaboration on research themes of common interest. This cooperation agreement brings concrete expression to the long-shared history of two international organisations that are emblematic of the strength of European science. It will foster synergies between the expertise, know-how and facilities available in the two organisations. ESA and CERN are the offspring of visionaries like Edoardo Amaldi and demonstrate that, when we share the same challenging objectives and join forces, Europe can be at the leading edge of progress, innovation and growth.

The ability of European citizens, policymakers and service-providers to access key environmental data on a routine basis took a major step forward following the launch of ESA’s Sentinel-1A satellite in April; the 2.3-tonne satellite lifted off on a Soyuz rocket from Europe’s Spaceport in French Guiana. Sentinel-1A opens a new page in the implementation of Copernicus, the second EU flagship space initiative after the Galileo satellite positioning system. The Copernicus programme will provide European citizens with the most ambitious space-based services in the world for environmental and security applications. 

 

The mission is the first of six families of dedicated missions that will make up the core of Europe’s Copernicus environmental monitoring network. Copernicus will provide operational information on the world’s land surfaces, oceans and atmosphere to support environmental and security policy-making and the needs of individual citizens and service providers. Whereas in meteorology satellites have been providing reliable data for weather forecasts for over 35 years, with the Copernicus programme we now have a similar information source for environmental services as well as for applications in the security and disaster management domain. 

 

On 29 May a Soyuz spacecraft launched from Baikonur cosmodrome in Kazakhstan and docked with the International Space Station in the early hours of the morning. On board were ESA astronaut Alexander Gerst and his crewmates Russian cosmonaut Maxim Suraev and NASA astronaut Gregory Reid Wiseman. Alexander’s 166-day mission included an extensive scientific programme, reflecting the diversity of research conducted on the Station: more than 40 experiments were of scientific value or prepared for further exploration missions covering materials physics, human physiology, radiation biology, solar research, biotechnology, fluid physics and astrophysics, in addition to a series of technology demonstrations. Alexander Gerst returned to Earth on 9 November.

The first set of high-resolution data on Earth’s magnetic field from ESA’s Swarm mission was unveiled at a conference in Copenhagen, Denmark on 19 June. The data showed how Earth’s protective shield had changed over the past six months. Launched on 22 November 2013, the three-satellite Swarm mission helps to improve our understanding of this mysterious aspect of our planet. The magnetic field protects us from cosmic radiation and charged particles that bombard Earth in ‘solar winds’. Without this protective shield, the atmosphere as we know it would not exist, rendering life on Earth virtually impossible. The strength of the magnetic field constantly changes – and it is currently showing signs of weakening. Swarm is the first space mission to provide long-term, high-resolution mapping of changes in the magnetic field.

The fifth and final mission of ESA’s Automated Transfer Vehicle lifted off on board an Ariane 5 launcher from Europe’s Spaceport in Kourou, French Guiana, heading for the International Space Station. Named after the Belgian scientist who formulated the Big Bang Theory, "Georges Lemaître" was the fifth and last ATV built and launched by ESA as part of Europe’s contribution to cover the operational costs of using the Space Station. ATV-5 docked with the Station on 12 August with a picture perfect manoeuvre - and for the second time in a row without any contact with the docking cone - to remain attached to the ISS for six months before leaving with waste material for destruction during atmospheric reentry. The vehicle delivered 6602 kg of freight: 2681 kg of dry cargo - including complex scientific hardware such as the electromagnetic levitator for experiments to improve industrial casting processes - and 3921 kg of water, propellants and gases. 

Comets are considered to be primitive building blocks of the Solar System and may have helped to ‘seed’ Earth with water, perhaps even the ingredients for life. But many fundamental questions about these enigmatic objects remain, and through a comprehensive, in situ study of the comet, ESA’s Rosetta comet chaser aims to unlock the secrets within. After launch and a decade-long journey chasing its target, on 6 August ESA’s Rosetta became the first spacecraft to rendezvous with a comet, opening a new chapter in Solar System exploration. At that time Comet 67P/Churyumov–Gerasimenko and Rosetta were situated 405 million kilometres from Earth, about half way between the orbits of Jupiter and Mars, rushing towards the inner Solar System at nearly 55 000 kilometres per hour. In addition to characterising the comet nucleus and setting the bar for the rest of the mission, final preparations began after the rendezvous for another space history first: the landing of the Philae lander on the comet’s nucleus, slated to take place on 12 November.

The pair of Galileo satellites, Galileo 5 and 6, was delivered into space on 22 August. This launch was to mark the start of a new phase in the European satellite navigation programme in which the full constellation would be deployed at an average launch rate of two satellites every three months. Unfortunately, the Soyuz rocket delivered the two satellites into the wrong orbit due to an anomaly in the Fregat upper stage. The two satellites that were supposed to be placed into a circular orbit close to a 23 500 km altitude, 3 hours 47 minutes after lift-off, ended up almost 4000 km short in an elliptical orbit and in a plane with the wrong inclination.

Fully under the control of ESOC, ESA’s operation centre in Darmstadt, Germany, the potential of exploiting the satellites to maximum advantage started being investigated immediately. The various ESA specialists, supported by industry and France’s space agency CNES, analysed different scenarios that would yield maximum value for the programme and safeguard, as much as possible, the original mission objectives. Moving the two satellites into an improved, more circular orbit, and implementing software patches on board and at ground network level so that both could provide operational services, was the scenario chosen. After the orbit-raising manoeuvres performed in October/November on satellite 5, a series of system tests was conducted. In December 2014, early results confirmed that satellite 5 was working as designed and providing excellent positioning fixes. The same "rescue" procedure is being applied to satellite 6 and should be concluded by early March 2015. The deployment of the constellation will now gather pace, with six to eight satellites launched per year in a series of Soyuz and Ariane 5 launches from the CSG, along with finalisation of the remaining elements of the ground network. Full Operational Capability of the system will see 30 satellites in place with initial services (Open Service, Search & Rescue, Public Regulated Service) scheduled to begin in 2016.

On 12 November Europe made history in space when ESA’s Rosetta mission soft-landed its Philae probe on a comet! After a tense wait during the seven-hour descent to the surface of Comet 67P/Churyumov-Gerasimenko, the signal confirming the successful touchdown reached Earth at 17:03 CET. The confirmation was relayed to Earth via the Rosetta orbiter and picked up simultaneously by ESA’s ground station in Malargüe, Argentina and NASA’s station in Madrid, Spain. The signal was immediately confirmed at ESA’s Space Operations Centre, ESOC, in Darmstadt, and DLR’s Lander Control Centre in Cologne, both in Germany. The first data from the lander’s instruments were transmitted to the Philae Science, Operations and Navigation Centre at France’s space agency CNES in Toulouse. Against the odds – with no downwards thruster and with the automated harpoon system not having worked – Philae bounced twice after its first touchdown on the comet, coming to rest in the shadow of a cliff. On 15 November, Rosetta’s lander completed its primary science mission after nearly 57 hours on Comet 67P/Churyumov-Gerasimenko. The lander returned all of its housekeeping data, as well as science data from the instruments designed for that purpose, including ROLIS, COSAC, Ptolemy, SD2 and CONSERT. The body of the lander was raised by about 4 cm and rotated by about 35° in an attempt to receive more solar energy. But as the last science data fed back to Earth, Philae’s power rapidly depleted. While descent images show that the surface of the comet is covered by dust and debris ranging in size from millimetres to metres, the astonishing panoramic images sent back to Earth show layered walls of harder-looking material. It is still hoped that at a later stage of the mission, perhaps when the comet is nearer the Sun, the lander might have enough solar illumination to wake up and re-establish communication. 

ESA’s ambitious Rosetta mission secured another place in the history books: not only was it the first to rendezvous with and orbit a comet, but it was also the first to deliver a probe to a comet’s surface. Thanks to Rosetta and Philae, scientists are now making the best-ever scientific analysis of one of the oldest remnants of our Solar System. Decades of preparation have paved the way for this extraordinary success, ensuring that Rosetta continues to be a game-changer in cometary science and space exploration helping to answer some of the biggest and most important questions on the history of our Solar System: How did it form and evolve? How do comets work? What role did comets play in the evolution of the planets, of water on Earth, and perhaps even of life on our home world? Rosetta will continue to accompany the comet until its closest approach to the Sun in August 2015 and beyond, watching its behaviour from close quarters to give us a unique insight and real-time experience of how a comet works as it hurtles around the Sun.

On 24 November a Soyuz spacecraft launched from Baikonur cosmodrome in Kazakhstan and safely docked with the International Space Station some six hours later, delivering ESA astronaut Samantha Cristoforetti and her crewmates to the weightless research centre where they would live and work for almost six months. On this mission – named "Futura" to highlight the science and technology research conducted in weightlessness that will help shape our future – Samantha is flying as an ESA astronaut for Italy’s ASI space agency, under a special agreement between ASI and NASA. After completing her mission on the International Space Station, Samantha Cristoforetti will land on the steppes of Kazakhstan on 14 May 2015. 

At the end of November, marking a first in space, Sentinel-1A and Alphasat linked up by laser across almost 36 000 km of space to deliver images of Earth just moments after they were captured. This important step demonstrates the potential of Europe’s new space data highway to relay large volumes of data very quickly so that information from Earth-observing missions can be made even more readily available. Having timely access to imagery from the Sentinel-1 mission, for example, is essential for numerous applications such as maritime safety and helping to respond to natural disasters. Orbiting from pole to pole about 700 km up, Sentinel-1A transmits data to Earth routinely, but only when it passes over its ground stations in Europe. However, geostationary satellites, hovering 36 000 km above Earth, have their ground stations in permanent view so they can stream data to Earth all the time. Creating a link between the two kinds of satellite means that more information can be streamed to Earth in near real time and in an almost continuous manner, which is key if operational services are to be operated to function in the event of natural disasters, and time means lives in such cases. Space engineers have turned to lasers to accomplish this.

ESA’s Council meeting at ministerial level took place in Luxembourg on 2 December. The main decisions are reflected in three sets of decisions: access to space, space exploration and ESA evolution. 

Europe’s access to space

Ariane 5, the roots of which were planted in the ministerial meeting of 1985, is a remarkable European success story: it has now performed more than 60 consecutive successful launches, has secured over 50% of the commercial market for launch services and generated direct economic benefits in Europe in excess of 50 billion euros. However, the global launch service market has changed rapidly, in terms both of supply and demand. On the supply side, new non-European launch service providers are now present in the commercial market at highly competitive prices, providing a challenge to the cost model of Ariane 5. On the demand side, satellites are also changing. The commercial market, consisting mostly of telecommunication satellites, favours the introduction of electric propulsion, which widens the range of telecommunication satellites’ mass in orbit and requires new orbit injection strategies. In response to these rapid changes, the ESA Executive and European launcher industry have defined a modular Ariane 6 in two configurations to serve the medium and heavy launch segments as of 2020, and an upgraded Vega launch system - Vega C- to serve the small launch segment. Ariane 6 will benefit from the re-use of Ariane 5 Midlife Evolution results and investments and from the common use of a solid rocket motor (P120C) both as first stage of Vega C and as strap-on booster for Ariane 6. 

In Luxembourg, Ministers took the decision to pursue the development of Ariane 6 and Vega C which, through modularity and flexibility, will be able to satisfy European institutional market requirements and compete on the worldwide commercial market. These development decisions are accompanied by a new governance of the European launcher sector with increased responsibilities being assigned to industry.

ISS exploitation and space exploration

In respect of the three destinations for exploration (LEO, Moon, Mars), the operation and utilisation of the International Space Station is an essential element. In addition to the invaluable research activities which are conducted on board the ISS, the Station yields a wealth of experience for ESA and its international partners that will be crucial as we plan the next stages of human exploration. The decisions taken in December by Ministers relate to supporting ESA’s ISS exploitation activities for the next three years (to the end of 2017, in view of continuing exploitation until at least 2020) as well as supporting its research activities with additional funding. As a contribution to ISS common operating costs, ESA is developing the Service Module for NASA’s Multi-Purpose Crew Vehicle, drawing upon the expertise gained with the ATV. Adequate funding to complete development the Service Module of the MPCV was included in the amount of money released at the Council at ministerial level. This is the first time that ESA is on the critical path of the development of a NASA crew transportation system, demonstrating the reliability of ESA and European Industry.

Regarding the Moon as a destination, ESA proposed preparatory elements of a contribution to Russia’s Luna-Resource Lander mission (planned for launch in 2019) and Lunar Polar Sample Return mission (planned for launch in the early 2020s). 

Regarding Mars as a destination, ESA’s ambitious ExoMars programme, involving two missions to Mars in 2016 and 2018, was also on the table for further subscription, which was granted in order to ensure the full implementation of the ExoMars programme. 

ESA evolution
The third topic on the agenda for Ministers, the evolution of ESA, focused on a vision to enable ESA to maintain its role as one of the world-leading space institutions, addressing its key relationships with its partners and its efficiency. The main partners of ESA are: its Member States, the scientific communities, industry, the European Union, European non-Member States and non-European States. These relationships are intricately interrelated and driven by the common objectives of achieving a competitive European space sector and ensuring maximum return on public investment in space. Since 2012, measures have been taken to strengthen ESA’s relationships with its Member States, seeking better coordination and cooperation of space programmes in Europe through the sharing of information on national space-related programmes. ESA’s relationship with the EU both in programmes and in setting the context in which the European space sector operates is vitally important for Europe. The previous Council at ministerial level in 2012 had mandated the Director General to elaborate and assess scenarios together with the European Commission for responding to a series of objectives on how this relationship might develop. 

In the Resolution adopted, Ministers confirmed the preference of Member States for a relationship between ESA and the European Union which maintains ESA as an independent, world-class intergovernmental space organisation and makes ESA the long-term partner of choice of the EU in the joint definition and implementation of the European Space Policy together with their respective Member States.

Highlights of 2015

In 2015 two new Member States become part of the Agency: Estonia and Hungary. The signatures of the accession agreements took place on 4 February and on 24 February respectively. ESA now numbers 22 Member States.

On 11 February, the Intermediate eXperimental Vehicle, IXV, was successfully launched on a Vega launcher from Europe’s spaceport in French Guiana to test the technologies and critical systems for Europe’s future automated reentry vehicles returning from low orbit. This was a first for Europe. The IXV is a "lifting body" combining the simplicity of a capsule like Apollo or Soyuz and the performance of a winged vehicle like the Space Shuttle. The IXV was injected into a suborbital path and separated from Vega at an altitude of 320 km. Thanks to its lifting body shape the wingless spaceplane then attained an altitude of around 450 km, allowing it to reach a speed of 27000 km/h when reentering the atmosphere at an altitude of 120 km – fully representative of any return mission from low orbit. During its hypersonic and supersonic flight it collected a large amount of data, while being controlled by thrusters and aerodynamic flaps. The spaceplane then deployed a parachute to slow its descent for a safe splashdown in the Pacific Ocean; at the end of its mission it was recovered by a ship and returned to Europe for detailed analysis to assess the performance and condition of the internal and external structures. The complete mission lasted approximately 100 minutes.

On 14 and 15 February, the undocking and reentry of ATV-5 Georges Lemaitre marked the end of the series of ESA freight vessels that has delivered cargo to the International Space Station, including food, drinking water, gases, research and maintenance equipment and around 3 tonnes of propellants each time. The versatile craft has also regularly boosted the Station’s orbit and occasionally manoeuvred the complex to avoid collisions with space debris. There will be no more ATVs but the technology will live on as part of the service module provided by ESA for NASA’s Orion spacecraft as part of the decisions taken at the ESA Council at Ministerial level in 2014. 

2015 will see the continuing launches of Galileo satellites to build the constellation. The next two -satellites 7 and 8 in the system- will be launched on a Soyuz from Europe’s spaceport in French Guiana towards the end of March. The pace of development will increase according to the satellite’s production rate of two every three months. The launch sequence will rely upon Soyuz (capable of carrying 2 satellites per launch) and Ariane 5 (with 4 satellites per launch). 

The first element of the European Data Relay System (EDRS-A) will be launched as part of the Eutelsat-9b satellite on a Proton launcher from the Baikonur cosmodrome in Kazakhstan in the course of 2015. The European Data Relay System will be an independent, European satellite system designed to reduce time delays in the transmission of large quantities of data. Data relay satellites are placed in geostationary orbit to relay information to and from      non-geostationary satellites, spacecraft, other vehicles and fixed Earth stations, which otherwise are not able to be in touch permanently with each other. EDRS will fill the gap of a European telecom network that is fast, reliable and seamless. It will make     on-demand data available at the right place and at the right time.

The launch of the second Copernicus satellite, Sentinel-2A, is scheduled to take place in June on a Vega rocket from Europe’s spaceport in French Guiana. Sentinel-2A is a multispectral optical mission capable of providing high-resolution data in 13 different channels with a pixel size of up to 10 m on the ground. The satellite will focus on monitoring changes in vegetation and coastal areas, is also suited to supporting disaster management during floods and earthquakes, and will provide information for supporting humanitarian aid activities. Copernicus is a joint initiative of ESA and the European Commission in which ESA is responsible for the development of the space component.

The Meteosat Second Generation (MSG) satellites were developed and built by ESA and are owned and exploited by EUMETSAT fulfilling user requirements for improved weather forecasting. The MSG-4 launch is slated for mid-June and will continue the successful series of operational meteorological satellites that started with Meteosat-1 in 1977. The first satellite, MSG-1, with its improved capabilities, was launched in 2002, followed by MSG-2 in December 2005, and MSG-3 in 2012. MSG-4 will be launched during the summer on an Ariane 5. 

During the summer, ESA’s future Mercury explorer BepiColombo will undergo thorough testing at ESA/ESTEC ahead of the launch campaign. In August, an international media event will present the flight hardware and the mission. BepiColombo is currently scheduled for launch in 2016 from Europe’s spaceport in French Guiana on board an Ariane 5 rocket. The spacecraft, slated to arrive at its destination in 2024, will study and understand the composition, geophysics, atmosphere, magnetosphere and history of Mercury, the least explored planet in the inner Solar System. BepiColombo represents the first time ESA and the Japanese space agency JAXA have joined forces for the implementation of a major space science mission. 

BepiColombo consists of two individual orbiters: the Mercury Planetary Orbiter (MPO) to map the planet, and the Mercury Magnetospheric Orbiter (MMO) to investigate its magnetosphere. Most of BepiColombo’s mission is especially challenging because Mercury's orbit is so close to the Sun. During the voyage to Mercury, the two orbiters and a transfer module, consisting of electric propulsion and traditional chemical rocket units, will form one single composite spacecraft. When approaching Mercury in 2024, the transfer module will be separated and the composite spacecraft will use rocket engines to bring it into polar orbit around the planet. When the MMO orbit is reached, the MPO will separate and lower its altitude to its own operational orbit. Observations from orbit will be taken for at least one Earth year with the possibility of an extension.

ESA astronaut Andreas Mogensen from Denmark is assigned to fly on the International Space Station from 1 to 11 September. Born in Copenhagen, Denmark on 2 November 1976, Andreas was selected as an ESA astronaut in May 2009 and completed the astronaut basic training programme at the European Astronaut Centre in Cologne, Germany in November 2010. During his flight, Andreas will test novel ways of interaction between the ground and space crews with a mobile device that allows astronauts to operate it hands-free and with several multi-user communication techniques. The system will also have advanced 3D visualisation and augmented reality – features that will be fully exploited with added wearable computers and cameras to allow the general public to follow activities on the ISS 'through the eyes of an ESA astronaut' potentially in real time. Andreas's short mission will provide an excellent opportunity to conduct several scientific studies, particularly in life science. By adding samples and measurements from a short-duration astronaut mission to material gathered and being collected during long-duration missions, the value of the biomedical statistics is increased. All the instrumentation needed for physiology, biology and material science experiments is already available in the Columbus laboratory and samples can be returned quickly back to Earth for further analysis. A short-duration mission is also perfect for testing a new generation of health sensors, vital measurement devices and electro-muscle-mobility devices. These have a direct benefit for future exploration missions and even sooner on Earth, for instance with operators of heavy machinery or rehabilitation after sports injuries. Andreas will be specially suited too: he will assess a new ‘skinsuit’ during normal daily activities. This is a tight garment made from elastic material mimicking Earth gravity and thus passively mitigating deconditioning of an astronaut’s body during spaceflight. With the arrival of Soyuz, the ISS will for a time host up to nine crew – a record that has not been broken since retirement of the Space Shuttle in 2011.

LISA Pathfinder is a technology mission aimed at testing the advanced devices for the measurement of low-frequency gravitational waves for the future LISA mission. It will be launched on a Vega rocket from the Guiana Space Centre in September. Virtually our entire knowledge about the Universe is based upon the observation of electromagnetic waves, such as visible light, infrared, ultraviolet, radio, X-rays and gamma rays. LISA Pathfinder will pave the way for a completely different method of observing the Universe: detecting gravitational waves – ripples in space-time predicted by Albert Einstein’s Theory of General Relativity. This will allow astrophysicists to address some of the most fundamental questions about the Universe and possibly raise new ones, such as the nature of inspirals and mergers of binary black holes, the most powerful transformations of energy in the Universe. LISA Pathfinder is a pioneering mission: not only are these technologies new, but they cannot be properly verified on the ground. This is because the Earth's gravity and environment would interfere with the test results. Only in space can the subtle effects of the low frequency gravitational waves be detected with exquisitely precise instruments.

In the last quarter we should be ready to launch the third Copernicus satellite, Sentinel-3A, on a Rockot vehicle from Plesetsk, in northern Russia. Sentinel-3 will measure sea-surface topography, sea- and land-surface temperature and ocean- and land-surface colour with high accuracy and reliability in support of ocean forecasting systems, and for environmental and climate monitoring.

ESA astronaut Tim Peake, from the UK, is assigned to fly on the International Space Station from November 2015 to May 2016 during Expeditions 46 and 47. Born in Chichester, England, on 7 April 1972, Tim was selected as an ESA astronaut in May 2009. He joined ESA in September 2009 and completed Astronaut Basic Training in November 2010. He received Eurocom certification in September 2011, which allows him to be responsible for communication between astronauts in orbit and Europe’s Mission Control Centre. In 2012 Tim completed training and certification for spacewalks using both the Russian Orlan spacesuit and the US Extravehicular Mobility Unit. He will be the first British ESA astronaut to visit the Space Station. Until his assignment was announced in 2013, Tim was Lead Eurocom for Luca Parmitano’s six-month mission that started in May of that year.

Special attention will be devoted to the "Climate Change Initiative" as part of the COP 21 conference on climate to be held in Paris from 30 November to 11 December. Climate change is arguably the greatest challenge facing mankind in the twenty-first century. Observations from space provide unique information which greatly assists the successful understanding and management of climate change. ESA's Climate Change Initiative is making full use of Europe’s Earth observation space assets to exploit robust long-term global records of essential climate variables such as greenhouse gas concentrations, sea-ice extent and thickness, and sea-surface temperature and salinity.

2014 has again been a very successful year for ESA, for its Member States and for the European space industry as a whole. A collective success that has allowed us to reach outstanding objectives once again, bringing progress in knowledge, service to citizens and competitiveness to European industry. I trust that this success will continue into 2015 and beyond especially because my mandate as ESA Director General will come to a close at the end of June. I feel very privileged to have been at the helm of this organisation for twelve years and wish to take this opportunity to thank all those who have supported ESA in this "journey through space" and contributed to our success story, in particular Member States, European industry and my colleagues at ESA. Nothing could have been achieved without them. I wish all the best to the European Space Directory which has proven to be a very valuable reference manual for all those involved in the space sector.