  New development approaches, including launch vehicles and advances in
sensors, computing, and software, have lowered the cost of entry into space,
and have enabled a revolution in low-cost, high-risk Small Satellite (SmallSat)
missions. To bring about a similar transformation in larger space telescopes,
it is necessary to reconsider the full paradigm of space observatories. Here we
will review the history of space telescope development and cost drivers, and
describe an example conceptual design for a low cost 6.5 m optical telescope to
enable new science when operated in space at room temperature. It uses a
monolithic primary mirror of borosilicate glass, drawing on lessons and tools
from decades of experience with ground-based observatories and instruments, as
well as flagship space missions. It takes advantage, as do large launch
vehicles, of increased computing power and space-worthy commercial electronics
in low-cost active predictive control systems to maintain stability. We will
describe an approach that incorporates science and trade study results that
address driving requirements such as integration and testing costs,
reliability, spacecraft jitter, and wavefront stability in this new
risk-tolerant "LargeSat" context.
