© 2020 Lockheed Martin Corporation   370              Figure 1 - Lockheed Martin Heritage Flex Arrays            Figure 2 - Lockheed Martin MM Solar Array  

Introduction  

The idea for the MM Solar Array was conceived in 2013 when Lockheed Martin desired a high- powered  solar array for its LM 2100 ™ fleet of commercial spacecraft. The goal of 25 kW  per vehicle (or 12.5 kW per  Wing) was established. The design team was faced with a significant decision: expand the current  generation of rigid solar arr ays or utilize Lockheed Martin’s heritage in flex arrays to develop a low -cost,  low-mass fourth- generation flex array. The trade studies that followed quickly concluded that the flex array  solution had significant mass and cost benefits at power levels gre ater than ~15  kW per spacecraft , so the  decision was made to invest in the flex array technology. For the next 5 years, Lockheed Martin invested  significant internal research and development dollars to sy stematically design, develop, and qualif y the MM  Solar Array for  flight programs. Every decision in the design process was asked 3 important  questions: h ow  does it impact cost, how does it impact manufacturing, and how does it impact modularity? The last of these  questions regarding modularity perhaps shaped the design of the MM Solar Array more than anything else.  Knowing that different satellites have different power requirements, the design team mandated that the  finished product be easily configurable for different power levels. The result was a very mod ular solar array  design. There are 375 documents that define the MM Solar Array. Of these 375 drawings, only 15 of them  require modifications to change the solar array from a wing that produces 12.5 kW to a wing that produces  6 kW  or 8 kW or 10 kW, etc. And most of these drawing m odifications are very basic  changes that simply  change the length of a certain assembly, like the mast or the blanket. This modularity enables the MM Solar  Array to be a fully qualified, turn -key solution for most any program. This means that on day one of the  program, the design of the solar array is already 96% complete. Non- recurring engineering efforts are  almost non-existent,  and production of the MM Solar Array can start almost immediately after contr act  award.  

Overview  

The MM Solar Array is divided into 4 major subassemblies. The first is the Boom Assembly. The structure  of the Boom Assembly consists of hollow composite tubes with bonded titanium end fittings that are  connected to each other across hinge lines. The purpose of the Boom Assembly is to deploy the MM Solar  Array far enough away from the vehicle so that the vehicle does not cast a shadow on the solar array  and  to improve the thermal view factor for the spacecraft . Harnesses that transfer power from the solar array to  the vehicle are routed along the Boom Assembly. The second major subassembly is the Deployer  Assembly. The structure of the Deployer Assembly is made up of composite panels with aluminum  honeycomb core and carbon- fiber facesheets . These panels are bolted together and support the  mechanisms that are used to deploy the solar array blanket. The Deployer Assembly is a one- time use  mechanism. Once the MM Solar Array is deployed, the Deployer Assembly serves as a piece of structure