ROOM
16
Special Report
atomic oxygen (in LEO), radiation and
micrometeoroid impacts. It may therefore be
necessary to deploy a protective shell structure
in orbit, in which assembly can proceed free
from many of these environmental concerns.
For LEO operations, there is also the continual
significant variation in the lighting environment
caused by going in and out of eclipse, which may
negatively impact vision-based operations.
Tele-robotic missions are impacted by
communication latencies and therefore require
tasks such as rendezvous and docking to be entirely
automated. When not supervised by an astronaut,
on-orbit assembly requires a robotic system with
high reliability and a high degree of ‘trust’ between
human and robot. New operational steps must be
developed to verify that the assembly procedures
have been executed as planned.
Some of the challenges faced by robotic,
autonomous on-orbit assembly can be addressed
by learning and benefiting from the much more
extensive worldwide activities of terrestrial-
based applications of the same technologies.
Use of automated, robotic assembly of complex
machines is widespread and growing in capability
on the ground across many industries. Important
examples include large industries such as
automotive and micro-electronics, as well as
assembly of components directly related to
spacecraft such as antennas and solar-cells.
Future impact
On-orbit assembly has the potential to radically
change the way in which spacecraft are deployed
for many important space missions. The already
long history of astronaut-assisted on-orbit
assembly combined with ongoing progress in
on-orbit inspection and servicing will have a
significant impact on on-orbit assembly in the
next decade, especially if the space sector is able
to leverage investment in terrestrial activities in
robotics and automation.
About the authors
Dr Iain D. Boyd
is a Visiting Scholar at the Science
&
Technology
Policy Institute (STPI), a Washington-based federally funded
R&D centre, where he supports studies commissioned by the US
government on topics ranging from space to quantum physics. His
research interests involve computer simulations of gas and plasma
flows. He has published more than 200 articles and is the author of
the book,
Nonequilibrium Gas Dynamics and Molecular Simulation
.
Dr Bhavya Lal
is a research staff member at the STPI’s Institute
for Defense Analyses (IDA), where she leads strategy, technology
assessment, policy studies and analyses in the space sector. She is a
member of the US-NOAA Advisory Committee on Commercial Remote
Sensing, and co-chairs a National Academy of Science committee on
assessing the infrastructure for space radiation testing.
In early 2016, ESA flew the Intermediate
Experimental Vehicle (IXV); in 2020 it is
expected to fly the Program for a Reusable In-
orbit Demonstrator from Europe (PRIDE). IXV
demonstrated many key capabilities for on-orbit
manoeuverability; PRIDE will provide a platform
for the experimentation with and development of
on-orbit servicing capabilities.
Self-assembly, which involves small satellites
with specialised capabilities self-organising
to fulfill the objectives of a larger mission, is
enabled by advances in formation flight. DARPA
is pursuing the Phoenix Satlet concept whereby
small autonomous modules incorporate key
satellite capabilities and aggregate in various
combinations to achieve different mission
goals. The modularity of the Satlets increases
mission resilience and re-configurability,
reduces spacecraft design and integration time,
and provides cheaper redundancies. In tandem
with the Payload Orbital Delivery (POD) system,
deployment costs are reduced. Satlets have been
under development since 2012, and the first LEO
flight is planned for 2017.
Operational challenges
Many on-orbit assembly capabilities face space
environment challenges, such as microgravity,
On-orbit assembly has the potential to radically
change the way in which spacecraft are deployed
for a number of important space missions
Artist impression of
Restore-L servicer
extending its robotic arm
to grasp and refuel a
client satellite on orbit.
Space Systems Loral
