Thales Alenia Space GOCE Project Manager: Interview with Andrea Allasio
Since ESA selected Thales Alenia Space in Italy as Satellite Prime Contractor for GOCE, Andrea Allasio has led an industrial consortium of more than 45 European companies to design and build the most advanced gravity mission for Earth Observation to date.
Andrea Allasio, an Italian national, has been working for Thales Alenia Space in Italy for 24 years. He has been Project Manager for GOCE since the beginning of the project.
Allasio gained a Masters in Electronics from the Polytechnic University of Turin in 1983. His 24 years of experience in system engineering and project management has included the Tethered Satellite project and the Tethered re-flight mission – joint ventures with NASA, supporting relevant Space Shuttle missions at NASA, as well as a number of ESA projects such as the Project Manager for the assembly, integration and verification for Mars Express.
ESA: Thales Alenia Space (Italy) is the Prime Contractor for the GOCE satellite and together with EADS-Astrium GmbH (Germany), Thales Alenia Space (France) and ONERA (France) constitutes the Industrial Core Team. What role does the Prime Contractor play?
As Prime Contractor, Thales Alenia Space has led the industrial consortium and designed the satellite system. This includes, for example, the so-called 'Drag Free Attitude Control System', which maintains GOCE's orbital altitude and keeps the accelerometer sensor heads in near 'free fall' – crucial for acquiring accurate gravity readings. Also included, is the design and implementation of the high-fidelity 'End-to-End Simulator', integration of the 'systems' into the satellite as well as testing and preparing the spacecraft for launch. We are also responsible for the commissioning phase once GOCE is in orbit. In addition, we have designed and verified the process of operating the satellite, which was implemented by ESA at its Spacecraft Operations Centre (ESOC) in Germany.
ESA: What have you been responsible for throughout the process of designing, building and launching GOCE?
I came into the project in mid-2000 when we were bidding on the contract and have been Project Manager since ESA awarded the contract to our company. For the last eight years I have worked very hard at building up the consortium, leading the team and solving any problems for the successful completion of the spacecraft and ultimately the mission as a whole. This has all been done in close cooperation with ESA and with the common goal of achieving the best-possible results. It's never always plain sailing in a complex project such as GOCE, but I have to say that our relationship with ESA's GOCE Project Manager Danilo Muzi has always been excellent and any problems have always been approached constructively. I believe that we've all grown thanks to this extraordinary experience.
ESA: GOCE must orbit at a very low altitude of just 260 km to observe the strongest possible gravity-field signal. What challenges did this represent in terms of design?
I would say that the larger 'systems' posed the biggest challenges, such as designing a flexible but robust drag-free attitude control system when it is difficult to predict the drag in space. Optimising the actual shape of the satellite to orbit at this altitude, putting in place the high degree of on-board autonomy required, developing a precise 'End-to-End Simulator' to predict performances, which is particularly difficult when they can't be measured on the ground because of the gravitational pull at the surface of the Earth – all these aspects have presented a number of challenges. The development of the gradiometer – the first ever taken into space – with its ultra-sensitive accelerometers and stable thermal environment has also been a huge technical achievement.
ESA: GOCE is also ultra-stable with no moving parts that would interfere with the gravity readings. How has this 'stability' been achieved?
We have used an extremely stable material that combines strength and rigidity with an extremely low coefficient of thermal expansion so that there is no distortion in the space environment. In addition, the project was subjected to a specific micro-vibration control plan with the aim of avoiding disturbances to the gradiometer measurement bandwidth (5-100 milli-Hz). This has driven the design of various elements and hardware, the selection of components and materials to be used.
ESA: GOCE is the most advanced gravity mission to date, demonstrating European excellence in engineering and new technology in space. Will advancements made here also benefit future space missions?
Definitely, in addition to on-going studies for GOCE follow-on missions, all the technologies that have been specifically developed for GOCE, such as the accelerometers, the ion-propulsion system, the drag free control, together with their technical implementation and lessons learned over the last eight years all form a solid know-how for the benefit of a variety of other space projects. A small, but important example is the 'nano-balance'. Based on precise laser interferometry and developed by the Prime Contractor during the beginning of the GOCE project, it measures thrust in the micro-Newton range. It has since been used for the characterisation of the thrusters for the French Microscope mission and ESA's Gaia mission. It is planned to be used for ESA's Lisa Pathfinder mission and the technology is also used in studies on laser interferometry for gravity-field monitoring conducted by Thales Alenia Space for ESA.
ESA: Once GOCE is operational, does Thales Alenia Space still have a role to play in the mission?
Yes indeed, after the three-month commissioning phase Thales Alenia Space Italia has already agreed with the Agency on a framework of mission support, corroborated by the competencies of the other Core Team members – EADS-Astrium, our colleagues from Cannes and ONERA. During the mission, we will support ESA during this crucial phase by analysing the spacecraft data, checking performance and giving suggestions if there are anomalies, and fine-tune the system. As you know, because of the low altitude, the satellite will encounter some drag but this can't be accurately predicted until in orbit. Although solar activity, which affects the drag, is expected to be low this can suddenly change. The GOCE test bench model will be kept operative in Turin for eventually cross-checking the in-flight behaviour of the spacecraft, as well as for verifying eventual software patches prior to sending them to ESOC for upload to the satellite.
ESA: Where will you be for launch?
I plan to be at the Plesetsk Cosmodrome for a dry run of the launch sequence carried out five days before launch. I will then be on duty to support the Agency during the real launch, and of course share the enjoyment of the event with the 20-strong Italian Thales Alenia Space team that has been at the launch site since the end of July preparing the spacecraft for the big day.
This is one in a series of interviews with a few of the key people that are involved in the GOCE mission. Please check back as the list will be added to over the coming weeks.