Space Development Agency (SDA)
The Space Development Agency (SDA) is a United States government entity that researches, develops, and fields next-generation technology for the United States’ Department of Defense’s National Defense Space Architecture (NDSA).  The SDA was founded in March 2019 under the umbrella of the Undersecretary of Defense for Research and Engineering. The agency was designed to operate outside the existing architecture of the satellite acquisition system, i.e., to establish its own way of designing satellites, so that it could establish itself as soon as possible. Key goals for the SDA include developing a LEO constellation (similar to Blackjack) and creating a surveillance mesh to track hypersonic glide weapons from unfriendly countries, namely China and Russia. 
For the LEO constellation, named JADC2, SDA released solicitations for 10 satellites to build the framework of its message transport layer. The idea behind JADC2 is to have a mesh of “sensors” and “shooters” operating all in space which will communicate information similar to a relay constellation. The end goal of JADC2 is to remove the ground station bottleneck across the United States’ military programs and rely totally on optical links from a space-based sensor to its message transport layer. This will allow various military programs to skip ground station relays and use entirely space-based communications for exchanging information in one secure protocol, which differs from that of a traditional communications satellite network.  By 2026, it is expected that the SDA’s constellation will have global coverage. Currently, the SDA is an independent entity, but the United States Congress directed that the SDA be absorbed by the U.S. Space Force no later than 2022. 
The SDA is planning to launch its NDSA in 2022. Leading up to this, the SDA will be launching several demonstration satellites throughout 2021. Most of the active U.S. Space Force constellations consist of several satellites in GEO. However, the NDSA will be made up of hundreds of satellites operating in LEO arranged into multiple layers to provide various capabilities including tracking hypersonic weapons and beyond-line-of-sight targeting.
Mandrake II and LINCS are the first two projects being launched with the goal of demonstrating optical intersatellite crosslinks. This will be a key enabling technology for the NDSA and will be used to create a mesh network with the SDA’s transport layer satellites, currently being developed by Lockheed Martin and York Space Systems. The mesh network will be able to move data rapidly between satellites to facilitate on-orbit processing and connect sensor data collected by any satellite to a specified war-fighter on the ground in a matter of seconds. 
In June of 2020 the Space Development Agency (SDA) published an draft of a proposed Optical Intersatellite Link (OISL) Standard setting forth a notional baseline for interoperable design parameters. 
In June of 2021 the SDA released SDA Tranche 1 Optical Communications Terminal Standard seeking to develop protocol definitions for optical communications systems including space-to-space (OISLs), space-to-air, space-to-maritime, and space-to-ground optical communications.