Proba-2

The most effective way of establishing new technology is ready for space is to go ahead and try it in space. ESA’s In-Orbit Demonstration activities exist to provide early flight access to the most promising innovations.

ESA and other space agencies employ a Technology Readiness Level (TRL) scale, denoting the nine different levels that new technologies have to pass through before being regarded as fully mature. In-orbit demonstration is right at the top of the TRL ladder: to be accepted, new products need to be demonstrated in orbit, particularly when users require evidence of flight heritage or when there is a high risk associated with their use.

ESA being an R&D agency, virtually all its missions are ‘experimental’ in the sense of doing something never before done. Precisely because of the highly innovative character of ESA missions, project managers have to focus on their project’s numerous mission driven innovations and cannot accept additional demonstrations.

This sound project management practice is fully understandable, but means carrying technology development forward to in-orbit demonstration has to be carried out independently of ESA missions.

Part of ESA’s General Support Technology Programme (GSTP), the In-Orbit Demonstration Element finds flight opportunities for innovative technologies. It also serves to demonstrate new research techniques - such as the utilization of reflected navigation signals - or new operational monitoring techniques, for instance exploitation of Automatic Identification System signals from global ship traffic. This element also supports the demonstration of in-orbit operational techniques , such as formation flying or re-entry, and associated technologies and products.

Another role is acquiring data on spacecraft and space environments to prepare the deployment of future innovations – for example, characterising radiation effects to estimate the vulnerability of Micro-Electro-Mechanical System (MEMS) devices.

The In-Orbit Demonstration Element includes a dedicated series of technology demonstrator micro-satellites, namely the Proba missions. Demonstrations are also achieved through placing technology experiments on ‘carriers of opportunity’, such as the International Space Station or ESA space missions with the capacity to host guest payloads.

Prioritising experimentation means accepting a greater level of risk than a standard mission. This becomes an acceptable trade-off because costs are kept low. The Proba series follows the ‘Lightsat’ approach, with cost-efficiency and robust simplicity followed across all phases of development, from initial system studies through to final operations.

Ground and space segments are designed in an integrated way to reduce complexity and budgets. Proba satellites are built for maximum autonomy to cut ground support requirements to the bare minimum. This “way of doing” in-orbit demonstration is also an objective in itself. New development practices are unavoidable to implement in-orbit demonstration within strict cost limitations. And once tried for Proba satellites they are then adopted by main stream projects.

In addition to GSTP, ESA’s Advanced Research in Telecommunications Systems (ARTES) programme supports also demonstration in-orbit with precursor missions and technology demonstration payloads.

Broadening access to space in this way represents an effective means of building industrial skills and capacity, especially for smaller companies and new member states. It builds industrial competitiveness and widens the portfolio of mature space technologies for operational ESA missions to draw upon, increasing their effectiveness.