"Construction is done. Now, we're in the handover phase, where ESA Engineering is passing the station facility over to ESA Operations and we're verifying that it meets all specifications," says ESA's Roberto Maddè, manager of the construction project.
ESA’s new 35m deep space tracking station, DSA 3, located near the town of Malargüe in Mendoza province, Argentina, will join two existing stations – DSA 1 and 2 – in New Norcia, Australia, and Cebreros, Spain, to provide global coverage for the Agency’s deep-space missions.
First signals received from Mars Express
With major construction complete, teams are preparing DSA 3 for formal inauguration late this year and entry in routine service early in 2013. The first test signals were already received in June 2012 from Mars Express, over a distance of about 193 million km. After that, many more satellite passes were performed, proving that the station is ready for duty.
Teams including radio engineers and ESTRACK network specialists at ESA's ESOC operations centre, Darmstadt, Germany, have been working on the station project since 2008.
Not so far from... no where
The site, about 1200 km west of Buenos Aires, was selected in 2009, and construction from bare ground started in 2010. Building the giant structure was contracted to an industrial grouping led by SED Systems (Canada) and Vertex Antennetechnik (Germany). These were supported by more than 15 specialised industrial partners from countries including Germany, France, Spain, Switzerland and Argentina.
Currently, explains Maddè, the station is undergoing specific performance and functional tests. Engineers are also adapting monitoring and control software used at the other DSA stations to function on the new Malargüe hardware. These will have been completed by the end of October. In November, the final steps will be taken to internally hand over the station from the ESTRACK design and development teams to the ESTRACK station operations teams here at ESOC.
On 7 December 2011, the huge 35 m-diameter dish antenna for the new deep space station was hoisted into place (time-lapse video).
"We're already doing regular tracking passes with Venus Express, and we're checking and comparing our performance with ESA's Cebreros station. So far, Malargüe is exceeding all design specifications and is performing beautifully," says Maddè.
The station has also contacted the Kepler spacecraft, NASA's first mission capable of finding Earth-size planets around other stars. It's in an Earth-trailing heliocentric orbit, approximately 1 AU from Earth.
The Kepler track over Malargüe and the joint quasar catalogue campaign went very smoothly and validated once again the benefits of the ESA/NASA cross-support partnership. While the Kepler pass was important for ESA to validate their Malargüe capabilities, it was also instrumental in helping NASA's Deep Space Network troubleshoot an issue with the telemetry data that had been observed at our Goldstone station. The ESA shadow track of the Kepler spacecraft was instrumental in narrowing down the root cause (as the same issue was observed during the simultaneous passes over ESA Malargüe and DSN Goldstone stations).
– Susan C. Kurtik, Jet Propulsion Laboratory,
Deep Space Network (DSN), Mission Support Manager
Testing focuses on the accuracy of acquiring spacecraft, the ranging and Doppler measurement systems, pointing accuracy (the giant, 610-tonne antenna can be pointed with an accuracy of just a few millidegrees) and doing the final geodetic survey to precisely locate the station on Earth.
While ESA’s three deep-space stations are substantially identical, the Malargüe station is uniquely equipped with a seismometer, made accessible to Argentina’s National Institute of Seismic Prevention (INPRES). “Mendoza province is seismically active, and monitoring such activity will greatly help in assessing its effects on actual antenna performance,” says Maddè.
Excellent location for deep-space communications
The Malargüe location offers a number of significant advantages:
- The southern hemisphere is a preferable site for all planetary missions
- It was possible to obtain a satisfactory hosting agreement for a long-term (multi-decade) site lease and frequency licensing with Argentina
- It is located approximately 120º from both DSA 1 and 2, giving ESA for the first time full 360º coverage
- It does not duplicate existing tracking capability (NASA has its Deep Space Network station at Goldstone, but that's in the Northern hemisphere of the Americas)
- It is far away from many terrestrial sources of radio-frequency interference, such as mobile-phone-using populations or terrestrial radio links
- It is located on a flat, open plain at some 1550m altitude, offering good local visibility and low atmospheric attenuation on radio signals
Yet the site is not so remote that installing power and telecommunication links was too difficult.
"ESA experts at ESOC are responsible for the design, development and upgrade of ESA’s deep-space stations, with the construction, integration and maintenance being contracted to European industry," says Juan Miró, Head of the Ground Systems Engineering team at ESOC. "We also control and operate all ESA ground stations in the ESTRACK network from ESOC, and their use is set to grow with ESA's future science missions."
Miró adds: "Thanks to the long-term development and use of technical standards agreed between space agencies, ESA and NASA deep-space stations are fully interoperable, and, in general, any of ESA's ESTRACK stations can support most NASA missions and vice versa."
The 'common technical standards' are agreed between the major space agencies in the frame of the CCSDS (Consultative Committee for Space Data Systems) organisation, an international technical body.
Building up a quasar catalogue with NASA
In the future, Malargüe will also contribute (together with NASA/JPL) to a growing catalogue of calibration sources – quasars – to be used in the highly accurate ‘delta - Differential One-Way Ranging’ (Delta-DOR) technique for locating spacecraft in our Solar System. For that purpose, a NASA/JPL ad-hoc receiver has been temporarily installed at the station. The catalogue of sources will be available to all CCSDS member Agencies who employ Delta-DOR (including ESA, NASA, JAXA, Roscosmos and China).
Delta-DOR uses quasi-stellar radio sources – very energetic and distant active galaxy centres – together with spacecraft signals collected simultaneously from two ground stations to fix the location of a spacecraft to within a few metres.
Jewels in the crown
The three 35m DSA stations are the 'jewels in the crown' of the Agency's ESTRACK network, which comprises 10 core stations:
- Kourou (French Guiana)
- Maspalomas, Villafranca and Cebreros (Spain)
- Redu (Belgium)
- Santa Maria (Portugal)
- Kiruna (Sweden)
- Perth and New Norcia (Australia)
- (and now) Malargüe (Argentina)
The remaining stations have 15m antennas and are used primarily for Launch and Early Orbit Phase (LEOP) tracking and for near-Earth missions.
Upon entry into routine service in early 2013, Malargüe will be assigned to track current missions like Venus Express and Mars Express. Later, in 2014, it will support Rosetta's return from hibernation and arrival at its comet destination.
One of the world's best tracking stations
"It's been an extremely busy 48 months of work on DSA 3, but we're finally at the end of the road and we've got an excellent new station – one of the world's best – of which all Europeans can be proud," says Maddè.
"There's no doubt, it was a team effort and we could not have achieved our goals without a lot of excellent work from many people at ESA and at our industrial partners. We are looking forward to getting DSA 3 into full operation early in 2013."