Estrack (ESA's Global Ground Network)
As ESA celebrates the 100th launch of Ariane 5 in September 2018, the Agency's worldwide ground station network is also marking ten years of providing vital tracking services to launchers soaring out of Kourou. 1) 2)
ESA's Earth-orbiting satellites and probes out in the Solar System are ultimately dependent on a small network of ground antennas, keeping them connected to their home planet. For ten years, this network has also been doing the same job for Europe's high-flying launchers.
Figure 1: ESA ground station network. The map is showing locations of Estrack stations as of 2017 (image credit: ESA)
Legend to Figure 1: This map is representational only and not all locations are shown with complete accuracy. The ESA tracking station at Perth, Australia, was retired from service in December 2015. The ESA stations at Villafranca and Maspalomas, Spain, were transferred to industry in 2017.
•Blue indicates core ESA-owned stations operated by the Estrack NOC (Network Operations Center) located at ESA's European Space Operations Center (ESOC), Darmstadt, Germany. 3)
• Orange indicates Augmented Estrack stations, procured commercially and operated on behalf of ESA by commercial entities.
• Green indicates Cooperative Estrack stations owned and operated by external agencies, but regularly providing services to ESA missions on an exchange basis.
"ESA's ventures into space have sent back vast quantities of scientifically vital data and beautiful images from our Solar System, yet without this little-known network, most of these incredible insights would never have reached Earth." explains Gerhard Billig, responsible for managing launcher tracking support at ESA's operations center in Germany (ESOC).
Named Estrack, this global system of ground stations provides links between satellites in orbit and the teams on Earth that control them, and of course the scientists who analyze their data.
The core Estrack network comprises seven stations in seven countries on three continents, all are centrally controlled from the Agency's operations center in Darmstadt, Germany. Four of these stations are used for tracking satellite or launchers near Earth and feature 13 m, 13.5 m or 15 m dish antennas: Kourou (French Guiana), Redu (Belgium), Santa Maria (Portugal) and Kiruna (Sweden).
ESA's ground network was established in 1975, with the first 15 m-diameter station located at Villafranca del Castillo, Spain, for the International Ultraviolet Explorer mission (and since then, the original Villafranca location has expanded to become ESAC (European Space Astronomy Center), ESA's major establishment in Spain.
In a typical year, the Estrack network provides over 15,000 hours of tracking support to 20 or more missions, with an enviable service availability rate above 99%.
Ten years of launcher tracking
In addition to catching signals from satellites almost anywhere, 2018 marks ten years since Estrack stations began tracking the launch vehicles that deliver these satellites into orbit, starting in March 2008, with the Ariane 5 rocket that carried the ATV-1 cargo vessel, Jules Verne.
Initially established to communicate solely with satellites, Estrack was expanded to support their rockets in 2008 with the establishment of a ground station and 5.5 m-diameter antenna on Santa Maria Island in the Azores archipelago, Portugal. The first Estrack station with the capability to track launchers, Santa Maria provided ESA with the independent means of receiving information from launchers through all phases of their flights.
Santa Maria joined Estrack at the same time that the Automated Transfer Vehicle (ATV)-series of missions got underway; the five ATVs were a series of expendable spacecraft developed by ESA to carry supplies to the International Space Station, at about 400 km altitude.
The special Ariane launch trajectory for these missions required a dedicated station in the middle of the Atlantic Ocean. For the same reason, this station has continued to be used for all launches of Galileo satellites, helping orbit Europe's new navigation system.
In contrast, the original Ariane launcher tracking station network — operated by the French space agency CNES from Europe's Spaceport in Kourou — is tailored for a different launcher trajectory followed by most launches from Kourou. These deliver telecom satellites into geostationary orbit at 36,000 km.
Santa Maria tracks all launch vehicles operated from Europe's Spaceport: including the three world-changing launch vehicles, Ariane 5, Soyuz and Vega.
Estrack stations provide teams on site with vital information acquired from the launchers soaring overhead, which is then passed on to the CNES and Arianespace teams who control their flights.
"ATV-2 in 2011 was a particularly memorable launch," says Gerhard, who was at Santa Maria station at the time. Just minutes after liftoff from Kourou, while the Ariane rocket was in radio contact with our station, we could see it whizzing high over our heads in the clear night-time sky. We could actually make out the upper stage thruster burning! It was amazing to see the rocket speed across the horizon, like a comet through the sky. And what we saw visually, was being confirmed on our screens via the live telemetry link."
To date, the Estrack stations in Portugal and Western Australia have supported 35 launches, many of which were monitored by more than one ground station; 16 launches have been supported from Santa Maria, and 34 from Western Australia (20 from Perth and 14 from New Norcia).
Figure 2: ESA's Santa Maria ground station is located on the ‘Montes das Flores' (Hill of Flowers) on Santa Maria island in Portugal's mid-Atlantic Azores. It includes a Galileo Sensor Station (image credit: ESA)
Upgrading down under: In 2010, the existing New Norcia antenna in Perth, Western Australia, was upgraded for launcher tracking. It was used for tracking not only ATV and Galileo launches but also rockets delivering satellites to ‘Sun-synchronous orbits' and onto interplanetary trajectories.
"For a decade now, tracking services for both the launcher and the satellite are provided, a unique and important capability during the first, critical moments of a satellite's mission," says Gerhard.
In 2010, the existing New Norcia antenna in Perth, Western Australia, was upgraded for launcher tracking. It was used for tracking not only ATV and Galileo launches but also rockets delivering satellites to ‘Sun-synchronous orbits' and onto interplanetary trajectories.
"For a decade now, tracking services for both the launcher and the satellite are provided, a unique and important capability during the first, critical moments of a satellite's mission," says Gerhard.
Since the closure of the Perth station in 2016, its launcher tracking capability has been transferred to ESA's deep space station at New Norcia, also in Western Australia.
Transferring ownership of three ESA ground stations: 4)
As part of ESA's strategy to foster commercial competitiveness in Europe while focusing on its core aims, the agency has transferred ownership of several ground tracking stations for reuse by external organizations. By the end of 2017, ESA will have transferred three stations to national organizations in Spain and Portugal, who will take over the provision of satellite tracking services to a wide variety of commercial customers.
The three stations involved in the transfer are all equipped with 15 m-diameter dish antennas, suitable for supporting near-Earth missions, and are located in Spain, at Maspalomas and at ESA's space astronomy center near Madrid, and in Perth, Western Australia.
The new operators will be able to use the stations to offer tracking services on a commercial basis to customers worldwide, which also includes ESA, leaving the Agency free to focus on meeting the demanding technical requirements of its deep-space stations, in Spain, Argentina and Australia, and on operation of a select group of four other stations.
"The handover increases commercial capabilities and capacity in Europe, not only to the benefit of ESA but also for commercial partners," says Yves Doat, Head of Ground Facilities Infrastructure at ESA's mission control center, Darmstadt, Germany. "ESA will continue developing the new technologies needed for future communication, including very high data-rate optical communication and networking with exploration partners at the Moon, Mars and other deep-space destinations."
The handover of the Perth station was notable. The station's frequency licence was withdrawn by the national telecoms regulator in 2015, and the station could no longer operate where it was. After being decommissioned, ESA was faced with the not insignificant cost of tearing it down and disposing of the structure and technical equipment.
"Instead, the government of Portugal made a bid for the station and, following a cost-sharing agreement for dismantling and transportation, it was shipped to Santa Maria island, in the Azores, where it is being recommissioned and placed back into service by 2018," says Yves.
Augmented network: The ESA-owned and operated core Estrack network is complemented by commercially operated stations provided thru service contracts with organizations such as the Swedish Space Corporation (SSC), Spain's National Institute of Aerospace Technology (INTA) and Kongsberg Satellite Services AS (KSAT, Norway).
These include tracking stations located at South Point, Hawaii (USA), Santiago (Chile), TrollSat, Antarctica, and Svalbard (Norway) and Dongara (Australia). These stations are used especially during the LEOP phase of a mission immediately following launch, when the flight control team needs continuous communication with their satellite, beyond what can be provided by ESA's own stations.
International cooperation: ESA shares Estrack capacity with other space agencies, who in return provide tracking services to ESA missions under a number of resourcing-sharing agreements. These include networks and stations operated by ASI (Italy), CNES (France), DLR (Germany), NASA's Deep Space Network and Goddard Space Flight Center and JAXA (Japan).
For example, NASA's Deep Space Network stations routinely support Rosetta and Mars Express (as well as other, now-complete missions such as Huygens and Venus Express), while Estrack is supporting Japan's Hayabusa-2 mission to asteroid 1999 JU3 (arriving in 2018). In recent years, Estrack has provided support to missions operated by China and Russia, as well as tracking the descent of NASA rovers to the surface of Mars.
This global cooperation allows all agencies to make use of a wide number of ground stations in geographically advantageous locations, maximizing efficiency and enhancing scientific returns for all. This cooperation is made possible, in part, through ESA's strong support for the development and adoption of internationally recognized technical standards for sharing tracking data.
In accordance with ITU radio regulations and agreements between ESA and Estrack host countries, Estrack stations are fully licensed and their operation respects requirements such as minimum elevation angle and maximum power radiated, as well as any site-specific constraints included in these agreements.
Estrack stations are designed in accordance with the European Cooperation for Space Standardization (ECSS) standards.
DSA (Deep Space Antennas)
In 1998, ESA decided to establish its own network for tracking deep-space probes to cope with the expected rapid rise in the number of interplanetary missions. The aim was to establish three terrestrial stations about 120° apart in longitude to provide continuous coverage as Earth rotated.
In the 2000s, the first of three 35 m-diameter Deep Space Antennas (DSA) was built in New Norcia (Australia), followed by stations at Cebreros (Spain) and Malargüe (Argentina). These feature some of the world's best tracking station technology and enable communications with spacecraft voyaging hundreds of millions of kilometers in space. In August 2016, New Norcia station received signals from the international Cassini spacecraft orbiting Saturn, across more than 1.4 billion km of space.
New Norcia Facility: In March 2003, ESA inaugurated a new deep-space station 8 km south of the town of New Norcia, which is about 150 km north of Perth, in Western Australia. — The large antenna was completed in 2002, and engineers conducted pointing tests using NASA's Stardust mission in the lead up to operational readiness. It entered service as the first of the Agency's three deep-space tracking stations in March 2003, and has been used for communications with Mars Express, Rosetta, Venus Express and Gaia, among other ESA and partner agency missions. The antenna supports data transmissions and receptions in both S- and X-band.
The coordinates of the 35 m antenna are: -31° 2' 53.61", +116° 11' 29.40". The antenna is sited at 252.26 m with respect to the WGS-84 reference ellipsoid, a mathematically- defined reference surface that approximates the Earth's geoid surface.
Figure 3: ESA's New Norcia station, DSA-1 (Deep Space Antenna-1), hosts a 35 m-diameter parabolic antenna. DSA-1 communicates with deep-space missions, typically at ranges in excess of 2 million km. It is also capable of supporting the ultra-precise 'delta-DOR' (Delta-Differential One-Way Ranging) navigation technique (image credit: ESA/S. Marti) 5)
As of 2017, ESA's deep-space ground station at New Norcia, Western Australia, is also being powered in part by sunlight, thanks to a new solar power ‘farm' completed in August. The farm has 840 photovoltaic panels arranged in five double rows with a rated capacity of 250 kW. This is expected to generate 470 MWh of electricity annually, about 40% of the station's annual needs and equal to the electricity needed to power 134 typical households. 6)
"While we've only just completed the first full month of operation, the solar facility has already reduced our cost of purchasing electricity from the local power company by at least 30%," says ESA's Marc Roubert. "In the coming summer months, given some sunny, clear skies, we even expect to be able to deliver electricity back to the local grid."
The installation began in 2015 and is expected to provide a full return on investment within about 15 years. — In future, ESA will consider upgrading the sites in Spain and Argentina with solar power as well.
Cebreros Facility: ESA's new deep space radio antenna in Cebreros (Ávila, Spain) was officially inaugurated on 28 September 2005. The new 35 m antenna is ESA's second facility devoted to communications with spacecraft on interplanetary missions or placed in very distant orbits. Cebreros' first task was that of tracking ESA's Venus Express spacecraft. 7)
Figure 4: ESA's 35 m-diameter deep-space dish antenna, DSA-2, is located at Cebreros, near Avila, Spain. It is controlled, as part of the Estrack network, from ESOC (European Space Operations Center) in Darmstadt, Germany (image credit: ESA)
Malargüe Facility: The Malargüe station, Deep Space Antenna 3, is ESA's newest tracking station and is located 30 km south of the city of Malargüe, about 1200 km west of Buenos Aires, Argentina. DSA 3 hosts a 35 m-diameter antenna with transmission and reception in X-band and reception in Ka-band. 8) 9)
DSA 3 was inaugurated in December 2012 and entered full service in early 2013. Today, it provides daily support to missions such as Gaia, Mars Express, Rosetta and ExoMars.
Figure 5: Malargüe station supports many of ESA's most important exploration missions, including Rosetta, Mars Express, ExoMars, LISA Pathfinder and Gaia. It will also support cornerstone ESA missions like ExoMars 2020, BepiColombo and Juice, as well as partner missions from Russia, the US and Japan, among others (image credit: ESA/D. Pazos - CC BY-SA IGO 3.0)
Location: The coordinates of the antenna are 35° 46' 33.63" S (35.776°S), 69° 23' 53.51" W (69.398°W), and the station is sited at 1550 m above sea level.
The Malargüe station incorporates state-of-the-art technology. Its technical facilities comprise Ka-band reception (31.8–32.3 GHz) and X-band transmission and reception. It is prepared to host Ka-band transmission (34.3–34.7 GHz) and K-band reception (25.5–27 GHz). Its main functions are to receive telemetry, send telecommands and perform radiometric measurements (ranging, Doppler, Delta-DOR) on scientific and deep-space craft.
Operations: The station provides routine spacecraft tracking support to ESA's deep-space missions such as Venus Express and Mars Express, and scientific missions such as Herschel and Planck, as well as to other agencies' missions under resource-sharing agreements. Malargüe will also support future ESA scientific missions, including LISA Pathfinder, Gaia and BepiColombo.
For routine operations, the station is remotely controlled from ESOC, Darmstadt, Germany. Local maintenance and operation is provided by a team of five engineers.
Goonhilly goes deep space
ESA has three deep-space dishes, in Australia, Spain and Argentina, that provide leading-edge performance and full-sky coverage for tracking and communicating with missions like Mars Express, Gaia and ExoMars. Later this year, they will add the new BepiColombo mission to Mercury and, in the near future, ESA's Solar Orbiter, Euclid and Cheops. 10)
"The amount of science data flowing in from ESA's current missions, not to mention from future missions with improved instruments, is growing strongly," says ESA's Pier Bargellini, responsible for network operations. "By the middle of the next decade, ESA's deep-space communication needs for supporting today's missions, like ExoMars, and upcoming spacecraft, like Juice, is expected to exceed our present capacity by around half.
Developing commercial capacity: This is why ESA engineering teams are excited by a new initiative aimed at redeveloping part of Goonhilly Earth Station, an existing commercial station in Cornwall, UK, to enable it to provide Europe's first deep-space tracking services on a commercial basis.
Under the project, a 32 m-diameter dish built in 1985 will be upgraded to provide fast data links for missions far beyond Earth – typically exceeding 2 million km. In the future, once commercial capacity is available, ESA's deep-space antenna network will focus on supporting sophisticated missions demanding high-performance systems.
The project will be initially funded through a €9.5 million investment from the UK's Cornwall & Isles of Scilly Local Enterprise Partnership, a public–private regional economic development body, and will later include a smaller investment from ESA.
"Once the station upgrade work is complete, in about 24 months, Goonhilly will be able to complement ESA's own stations, and provide deep-space tracking for the Agency's missions as well as those of other space agencies or from private space start-ups aiming to exploit the Moon or mine asteroids," notes Klaus-Jürgen Schulz, responsible of ESA ground station engineering.
Goonhilly, established in 1962 and at one time the largest satellite station in the world, with over 60 dishes of varying size, is well known in the UK. Its antennas have brought iconic images to UK TV viewers, including Muhammad Ali fights, the Olympic Games, the Apollo 11 Moon landing and 1985's Live Aid concert.
With the growing demand for deep-space tracking for both space agencies and new commercial space companies, the Goonhilly upgrade is an excellent example of how ESA can foster new business for European industry through engineering contracts to transform existing antennas into state-of-the art deep-space ground stations.
Figure 6: Goonhilly Earth Station, a commercial tracking station in Cornwall, UK, will be upgraded to provide Europe's first deep-space services on a commercial basis (image credit: GES - Goonhilly Earth Station Ltd.)
Status of the station
• April 17, 2018: ESA has signed a collaboration agreement with Surrey Satellite Technology Ltd (SSTL) and Goonhilly Earth Station (GES) for Commercial Lunar Mission Support Services at the Space Symposium in Colorado Springs, USA. This innovative commercial partnership for exploration aims to develop a European lunar telecommunications and navigation infrastructure, including the delivery of payloads and nanosats to lunar orbit. 11)
- The partnership allows for a low-risk, phased approach to implementing a sustainable, long-term commercial service and will support lunar scientific and economic development across Europe and the rest of the world. The agreement includes the upgrade of the Goonhilly Earth Station for commercial deep space services and the development of the space segment with a lunar pathfinder mission. The cooperation also encompasses the commercial and regulatory support to catalyze the lunar economy and provide affordable access to the lunar environment, and ultimately deep space.
- The agreement was signed by Sir Martin Sweeting, founder and Executive Chairman of SSTL, Ian Jones, founder and Chief Executive of GES and David Parker, Director of Human and Robotic Exploration at ESA.
- David Parker commented, "The agreement between ESA and SSTL/GES establishes ESA's first partnership for providing commercial services in support of lunar missions. The Lunar Pathfinder mission would provide exciting new opportunities for science and technology demonstration and open deep space access to new actors."
- Following the recent announcement of the GES ground segment upgrade to form the world's first deep space commercial node, the partners are now jointly committed to the developing the Lunar Pathfinder space segment for a low cost "Ride and Phone Home" capability. The Lunar Pathfinder mission will offer a ticket to lunar orbit for payloads and nanosats onboard an SSTL lunar mothership spacecraft, which will provide communications data relay and navigation services between customer payloads and the GES Deep Space ground station.
• October 19, 2018: Satellite communications innovator and space gateway Goonhilly Earth Station has opened an office at the Cody Technology Park in Farnborough, Hampshire, UK, in support of the firm's plans to expand their consultancy, design engineering and small-scale manufacturing capabilities — The new office is located at the Cody Technology Park, Farnborough, Hampshire GU14 0LX. 12)
- The new site gives Goonhilly more space to expand their design engineering team and attract talented engineers in the South-East and South-West of England who are keen to work at the forefront of the UK's flourishing satellite communications sector. The teams in Farnborough and Goonhilly will collaborate closely.
- For example, while the Farnborough team will be focused on deep space antenna array design, their colleagues in Cornwall will undertake the implementation. Goonhilly is also recruiting and investing in small-scale advanced manufacturing/production facilities at their Cornwall headquarters, where it plans to build these next-generation systems.
1) "Ten years catching rocket signals," ESA, 26 September 2018, URL: http://m.esa.int/Our_Activities/Operations
2) "Estrack ground stations," ESA, 18 February 2018, URL: http://m.esa.int/Our_Activities/Operations/Estrack/Estrack_ground_stations
4) "Transferring ownership of three ESA ground stations," ESA, 16 November 2017, URL: https://m.esa.int/Our_Activities/Operations/Estrack/
5) "New Norcia - DSA 1," ESA, URL: http://m.esa.int/Our_Activities/Operations/Estrack/New_Norcia_-_DSA_1
6) "Going green to the Red Planet," ESA, 28 November 2017, URL: https://m.esa.int/Our_Activities/Operations/Estrack/Going_green_to_the_Red_Planet
7) "ESA's new deep space antenna in Cebreros becomes a reality," ESA, September 2005, URL: http://m.esa.int/About_Us/ESOC/ESA_s_new_
8) "Malargüe - DSA 3," ESA, URL: https://www.esa.int/Our_Activities/Operations/Estrack/Malarguee_-_DSA_3
9) "ESA boosting its Argentine link with deep space," ESA, 25 April 2017, URL: http://m.esa.int/Our_Activities/Operations/
10) "Goonhilly goes deep space," ESA, 22 February, 2018, URL: https://m.esa.int/Our_Activities/Operations/Estrack/Goonhilly_goes_deep_space
11) "ESA signs collaboration agreement for commercial lunar missions," ESA, 17 April 2018, URL: https://www.esa.int/Our_Activities/Human_Spaceflight/ESA
12) "Goonhilly Earth Station Expands Their Operations Enabling Multitasking in Multi Locations," Satnews Daily, 19 October 2018, URL: http://www.satnews.com/story.php?number=1798184766
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (firstname.lastname@example.org).