In-Orbit Assembly of Large Spacecraft Using Small Spacecraft and Innovative Technologies

Abstract

<p>The size of any single spacecraft is ultimately limited by the volume and mass constraints of currently available
\nlaunchers, even if elaborate deployment techniques are employed. Costs of a single large spacecraft may also be
\nunfeasible for some applications such as space telescopes, due to the increasing cost and complexity of very large
\nmonolithic components such as polished mirrors.</p>
\n
\n<p>The capability to assemble in-orbit will be required to address missions with large infrastructures or large
\ninstruments/apertures for the purposes of increased resolution or sensitivity. This can be achieved by launching
\nmultiple smaller spacecraft elements with innovative technologies to assemble (or self-assemble) once in space and
\nbuild a larger much fractionated spacecraft than the individual modules launched.</p>
\n
\n<p>Up until now, in-orbit assembly has been restricted to the domain of very large and expensive missions such as space
\nstations. However, we are now entering into a new and exciting era of space exploitation, where new mission
\napplications/markets are on the horizon which will require the ability to assemble large spacecraft in orbit. These
\nmissions will need to be commercially viable and use both innovative technologies and small/micro satellite
\napproaches, in order to be commercially successful, whilst still being safety compliant. This will enable
\norganisations such as SSTL, to compete in an area previously exclusive to large commercial players. However, inorbit
\nassembly brings its own challenges in terms of guidance, navigation and control, robotics, sensors, docking
\nmechanisms, system control, data handling, optical alignment and stability, lighting, as well as many other elements
\nincluding non-technical issues such as regulatory and safety constraints. Nevertheless, small satellites can also be
\nused to demonstrate and de-risk these technologies.</p>
\n
\n<p>In line with these future mission trends and challenges, and to prepare for future commercial mission demands, SSTL
\nhas recently been making strides towards developing its overall capability in “in-orbit assembly in space” using
\nsmall satellites and low-cost commercial approaches. This includes studies and collaborations with Surrey Space
\nCentre (SSC) to investigate the three main potential approaches for in-orbit assembly, i.e. deployable structures,
\nrobotic assembly and modular rendezvous and docking. Furthermore, SSTL is currently developing an innovative
\nsmall ~20kg nanosatellite (the “Target”) as part of the ELSA-d mission which will include various rendezvous and
\ndocking demonstrations. This paper provides an overview and latest results/status of all these exciting recent in-orbit
\nassembly related activities.</p>