Laser communications is well suited for space applications because it requires much less power and weight than radio frequency (RF) communications, has the capacity for higher data rates, and provides secure communications due to the narrow beam. NASA's Long Range Optical Communications subtopic seeks innovative technologies in free-space optical (FSO) communications for increased data volume from space missions in multiple domains. >100 gigabit/s for cislunar missions, >10 gigabit/s for Earth-sun-L1 and -L2 missions, >1 gigabit/s for deep-space missions, and >100 megabit/s planetary Lander-to-Orbiter missions. For fast data rates, the laser communications telescopes (LCTs) must be large-typically up to one meter diameter-and have low wavefront error (WFE) so the received beam can be focused onto a very small, fast detector. These telescopes must also have a very low coefficient of thermal expansion over a large variation of temperatures, have high thermal conductivity, be mechanically stiff and strong, and lightweight. Unfortunately, telescopes with these properties are very expensive to build. The purpose of this R&D effort is to develop telescopes for these space based applications that satisfy all the requirements mentioned above but are much less expensive to build. In Phase I, Team GT delivered mirror substrate and structure coupons to NASA for testing. This included a 30-mm aperture, 3D/AM off-axis parabolic substrate; and super-dimensionally-stable RoboSiC bolts. Testing results showed that the components are more than adequate for constructing a LCT that meets requirements. Now that component testing is complete, the objective of Phase II is to use these proven components and 3D/AM practices to design, manufacture, assemble, and deliver a complete laser communications telescope that meets or exceeds all NASA requirements including low cost. NASA Phase II Contract # 8ONSSC19C0138, addresses the manufacturing of an ultra-lightweight, ultra-stable RoboSiC (TM) lasercom telescope. Laser Communications Telescopes are needed by multiple Jet Propulsion Laboratory and multiple NASA cost centers for Cislunar, Earth-Sun-L1 and L2, Deep-space and for Planetary Missions with Orbiter-Landers.
