## 1 Introduction  
### Background  
Large amounts of data is being collected on satellites due to advancements in technology such as high resolution and multispectral imagers. High bandwidth communication is needed in space to transfer the collected data to Earth or other satellites where the data can be processed and utilized. Additionally, satellite missions are increasingly taking place outside of Earth's orbit to explore other planets and celestial bodies. These interplanetary satellite missions will likely have limited communication link opportunities and need to transfer as much data as possible during these windows.  
Small satellites, which are satellites with a mass less than \(\sim\)500 kg, can be used to fulfill these deep space missions. Small satellites have lower launch costs than larger satellites, since the launch cost increases with increasing satellite mass. Nanosatellites, which are satellites with a mass less than \(\sim\)10 kg, are a subset of small satellites. Nanosatellites have even lower launch costs and can be deployed into satellite constellations for large scale sensor acquisition and communication networks. Due to their small form factor, nanosatellites have strict Size, Weight, and Power (SWaP) requirements.  
Optical frequencies diverge less than radio frequencies, which enables optical signals to be collimated into a tighter transmitted beam. When utilizing optical frequencies for communication, the transmitted beam can maintain higher intensities for a longer distance and the receiver can capture a larger fraction of the transmitted signal. Optical sensor technology like avalanche photodetectors (APDs) and Gieger-mode APDs enable the detection of \(\sim\)100 photons down to a single photon. As a result, optical communication can have lower required transmitter power at the cost of stricter pointing requirements.  
The Lunar Laser Communication Demonstration (LLCD) was conducted on NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) satellite that launched in late 2013 [1]. The LLCD payload demonstrated optical communication in the 1.5 \(\upmu\)m band utilizing pulse position modulation (PPM) with 16 slots (16-PPM) to downlink data from the moon to a receiver on Earth at 622 Mbps [1]. The uplink from the optical ground terminal on Earth utilized 4-PPM to uplink data at 20 Mbps to LLCD [1]. LADEE was a small satellite that weighed 383 kg at launch and the entire spacecraft consumed 295 W of power during its mission [2]. The LLCD space instrument had a mass of 32.8 kg and consumed 136.5 W during communication activities [2]. Most of this power was used for precision beam pointing.  
The Micius Coherent Laser Communication Demonstration (MCLCD) is another small satellite free space optical link that was demonstrated on the Micius Quantum Science Satellite [3]. This 635 kg small satellite [4] was able to achieve a downlink with a data rate of 5.12 Gbps from Low Earth Orbit (LEO) to an optical ground facility [3]. As opposed to LLCD which used PPM, MCLCD utilized Differential Phase Shift Keying (DPSK), where the data is encoded with a phase modulator on a 1550 nm optical carrier [3]. The uplink from the optical ground facility to MCLCD achieved a data rate of 20 Mbps by utilizing 16-PPM and a 1064 nm optical signal [3].  
The Miniature Optical Communication Transceiver (MOCT) is a lasercom system being developed by the Precision Space Systems Laboratory (PSSL) at the University of Florida. MOCT aims to enable pulsed optical communication on a nanosatellite platform at lunar distances and closer. Since MOCT is designed for a SWaP constrained platform, it can also be used to provide power efficient, long distance optical communication on larger satellites and free up SWaP resources to be used by other spacecraft subsystems.