4: Mission design

Satellites designed to work in unknown hostile environments are the ultimate example of ‘form follows function’: no two missions are alike.

Any initial idea needs fleshing out through the setting of solid requirements: what are all the needs of the mission to best achieve its set goal? Where will it be going in space? What instrumentation payload will it require, how much onboard power is needed and how will its results be returned to Earth?

Experts must analyse every moment of a mission’s planned journey, from understanding its destination (A comet? An asteroid? A planet?) or fixed orbit (Low-Earth orbit? Geostationary orbit? Or out into deep space?) and selecting its launch vehicle and fixing its precise lift-off time to mapping out all its planned manoeuvres. This all provides vital data for the actual design of the spacecraft and also for the mission control systems and stations on the ground.

ESA’s BepiColombo mission, for instance, will perform nine planetary flybys to obtain vital gravity boosts before entering Mercury orbit – and each must be mapped out in 3D to just a few kilometres’ accuracy.

ESA’s Concurrent Design Facility, based at its technical centre in the Netherlands, gathers teams of experts to perform such ‘pre-Phase A’ studies of proposed missions, using networked systems to work together in real time, establishing a workable set of mission requirements which can then be passed to European industry through ‘invitations to tender’.

Mission development proceeds in terms of ‘Phase A’ – meaning initial industrial contracts, sometimes undertaken in parallel – to ‘Phase B’ when a single mission design reaches a preliminary buildable form.

In parallel, ESA specialists in space debris will assess the planned design, ensuring anything set to orbit Earth will be safely disposed of at the end of its mission, complying with debris guidelines and ensuring the continued safety of commercially and scientifically valuable orbits.

Other teams will ensure spacecraft can make use of specific frequencies for communications, a complex process involving direct liaison with the International Telecommunications Union to comply with international laws and standards and avoid interference with other satellites.

Next comes ‘Phase C’ when the spacecraft design is finalised, then ‘Phase D’ when it is actually built. ‘Phases E and F’ cover mission operations then finally disposal. ESA teams oversee progress through these phases, working with their industrial partners, with ESA technical experts embedded into each such team.

Next part: Inventing tomorrow

(Photo: A session at the CDF)

ESA Basic Activities at Space19+

For ESA’s next Ministerial Council, Space19+, set for the end of this year, the Agency is asking Europe’s space ministers for a substantial investment for its core Basic Activities, helping to support a new generation of space missions as efficiently as possible. ESA’s Basic Activities have three main objectives: to enable the future through early stage research and development, commencing the Agency’s seamless grid of innovation; develop and maintain ESA’s common infrastructure and expertise; and, develop, preserve and disseminate knowledge for European capacity building and sustainable growth – inspiring and promoting creativity.