Steven Buckley

Responsive satellites and the need for structural health monitoring

The United States is striving to develop an Operationally Responsive Space capability. The goal is to be able to deliver tailored spacecraft capabilities to the warfighter as needs arise. This places a premium on the timespan between generating that requirement and having a functioning satellite performing its mission on orbit. Although there is lively debate regarding how to achieve this responsive space capability, one thing remains undeniable; the satellite flight qualification and launch vehicle integration process needs to be dramatically truncated. This paper describes the Air Force Research Laboratorys attempts to validate the use of Structural Health Monitoring (SHM) in lieu of traditional structural flight qualification testing schemes (static and shock loads, random vibration, coupled loads analysis, thermal vacuum testing, etc.) for potential Responsive Space (RS) satellites.

Development of a satellite structural architecture for operationally responsive space

The Air Force Research Laboratory/Space Vehicles Directorate (AFRL/RV) is developing a satellite structural architecture in support of the Department of Defenses Operationally Responsive Space (ORS) initiative. Such a structural architecture must enable rapid Assembly, Integration, and Test (AI&T) of the satellite, accommodate multiple configurations (to include structural configurations, components, and payloads), and incorporate structurally integrated thermal management and electronics, while providing sufficient strength, stiffness, and alignment accuracy. The chosen approach will allow a wide range of satellite structures to be assembled from a relatively small set of structural components. This paper details the efforts of AFRL, and its contractors, to develop the technology necessary to realize these goals.

DEPLOYMENT AND RELEASE DEVICES EFFORTS AT THE AIR FORCE RESEARCH LABORATORY SPACE VEHICLES DIRECTORATE

Small satellites require a variety of release devices to accomplish mission-related functions such as separation from the launch vehicle, separation from each other, and deployment of instruments. This paper summarizes low-shock non-pyrotechnic separation efforts that are being managed by the Air Force Research Laboratory Space Vehicles Directorate (AFRL/VS). The AFRL/VS has been actively developing low-shock, non-pyrotechnic spacecraft release devices to mitigate problems associated with traditional pyrotechnic release devices. Specifically, pyrotechnic devices produce high shock, create unnecessary contamination, and have costly handling requirements due to their hazardous nature. Small satellites are particularly susceptible to shock related failure because of the close proximity of sensors and instruments to the shock source. Reducing shock-induced loads on the spacecraft dramatically lowers the overall cost of a spacecrafts design, testing, and operation. Lower loads allow spacecraft components, such as solar arrays and other flexible structures, to be made lighter and use less expensive materials. This results in both smaller mass and reduced production costs. The AFRL/VS is sponsoring the development of several innovative technologies that can provide solutions to these problems. The devices are being designed to replace existing separation and deployment systems.

Multiple payload adapters; opening the doors to space

In order to increase the number of satellites that can be flown on a small, fixed budget, low-cost multiple payload adapters (MPAs) are needed to take advantage of excess payload capability on launch systems. This paper will discuss the development of several MPAs at the Air Force Research Laboratory-Space Vehicles Directorate (AFRL/VS) in support of current and future Air Force and DOD requirements. The adapters are being designed using state-of-the-art manufacturing processes, launch vibration isolation, and low-shock separation technology that can accommodate multiple satellite configurations. The MPAs can deploy multiple satellites, in a large range of sizes (15 kg to 1000 kg), depending on the design configuration. The MPAs are being developed to support the Minotaur, the Evolved Expendable Launch Vehicle (EELV), as well as the Space Shuttle. The successful development of these adapters will greatly reduce the cost of launching satellites into orbit by allowing for the efficient use of currently unused payload margins.

Structural health monitoring: an enabler for responsive satellites

The Air Force Research Laboratory/Space Vehicles Directorate (AFRL/RV) is developing Structural Health Monitoring (SHM) technologies in support of the Department of Defenses Operationally Responsive Space (ORS) initiative. Such technologies will significantly reduce the amount of time and effort required to assess a satellites structural surety. Although SHM development efforts abound, ORS drives unique requirements on the development of these SHM systems. This paper describes several technology development efforts, aimed at solving those technical issues unique to an ORS-focused SHM system, as well as how the SHM system could be implemented within the structural verification process of a Responsive satellite.

Development of a low-cost, modular, reliable, Shuttle-launched payload booster

The Space Shuttle is an inexpensive, reliable vehicle for small satellite launch for the Air Force Space Test Program (STP). Unfortunately, typical Shuttle orbits have a limited lifetime due to their low altitudes. One way to allow the STP to take advantage of the low Shuttle space lift cost is to employ a small propulsion module to boost the STP satellite from the relatively low Shuttle orbit to a higher orbit. Current Propulsion Module (PM) technologies are expensive and have difficulties conforming to the man-rating requirements of the Shuttle. The Space Vehicles Directorate of the Air Force Research Laboratory (AFRL/VS) seeks to solve this problem by developing PM technologies that will lower costs, improve performance, and increase the reliability of these systems, facilitating approval to fly on the Shuttle. The AFRL/VS will fund the development of several innovative technology efforts to design this proposed propulsion system to meet the STP requirements. It must be a lightweight, maneuverable vehicle that also meets Shuttle safety requirements. This system will also be compatible with current Space Shuttle Hitchhiker Experiment Launch System (SHELS) configuration for mounting in the Space Shuttle cargo bay, i.e. weight and volume requirements. The PM will also have a re-startable motor and appropriate avionics to provide flexible orbit transfer support.

Utilizing Excess Capacity of Current Launch Vehicles to Lift Secondary Payloads

Spacelift is a precious commodity that should never be wasted. Taking advantage of excess capacity on space launch vehicles is crucial to orbiting as many satellites as possible and is sometimes also the only path to orbit for many small and low-priority payloads. There have been many attempts to utilize this excess capacity over the years. Recent successes include the EELV secondary payload adapter (ESPA) and the manifesting of small secondary payloads on Minotaur and Falcon I launch vehicles. In most cases, the process of adding secondary payloads to an existing launch mission is problematic due to a variety of reasons including politics, funding, compatible requirements, and availability of crucial tools such as multi payload adapters. This paper will examine the factors that impact the development of multiple manifest launch missions. In particular it will identify the various types of secondary payloads that have been flown, outline the history of adapter development for smaller payloads, and identify the critical elements necessary to successfully manifest multiple satellites on one launch vehicle. Finally, this paper will outline a successful process to put small secondary payloads on all Minotaur launch vehicles and identify a growth path that others can follow to take advantage of excess launch capacity most efficiently.