STRaND-1 and TDS-1: How the UK Does Low Cost Tech Demo

A perrenial question of Cubesats is why they are not yet used as platforms for truly operational application missions. The STRaND-1 mission described in this paper is used to demonstrate the hurdles which must be overcome in order to create cost-effective CubeSat platforms that are ready for operational missions with satisfactory design lifetime, reliability and availability objectives. STRaND-1 is the UK’s first CubeSat, and will be launched on the 25th of February 2013 on a PSLV into a dawn-dusk sun-synchronous orbit. As with many CubeSats, the goals of the successful 3U mission were rapid training and technology demonstration. The novelty (other than the technical novelty of testing the robustness of mobile phone electronics in the LEO environment) was the volunteer nature of the team, and that the organisations involved had previous operational small satellite mission experience. This paper takes a holistic view of the mission, critically reviewing the mission lifecycle from the initial concept design through to integration and testing, LEOP and initial mission results in respect of these hurdles to operational applications. The UK\u27s small satellite technology demonstration mission - TDS-1 - is presented for contrast. Now ready for flight in Q3 2013, TDS-1 is an example of how a collaborative small sat technology demonstration mission can be accomplished at low cost and inside a rapid schedule. TDS-1 incorporates a suite of eight separate sensor payloads plus a novel set of advanced avionics. The design, concept of operations and management of TDS-1 enabled the platform enough flexibility to accommodate the payloads to change in both number and in bus resources required throughout the programme lifecycle, while avoiding the pitfalls of over-designing the system. The review is conducted with an eye to how a CubeSat mission differs from the commercial, small satellite approach to spacecraft engineering. In particular, lessons learnt on CubeSat general system design philosophy, data bus topologies, and management philosophies are discussed and compared against the more traditional small sat approach, something on which the Surrey community can speak with authority. Conclusions are drawn on the the similarities and differences of the small-satellite approach pioneered in the 1990s and the CubeSat approach pioneered in the 2000s, with recommendations on where commercial, small satellite engineering philosophy can be applied to the hypothetical operational CubeSat mission, and vice versa