The Mightysat fleet. Photo: AFRL

MightySat 2 is an Air Force Research Laboratory (AFRL) multi-mission, small satellite program that demonstrates on-orbit high-payoff space system technologies. The MightySat 2 series of spacecraft will provide AFRL with a "lab bench" for responsively testing emerging technologies to ensure their readiness for operational Air Force missions. As a follow-on to MightySat 1 - a single, $5 million satellite which successfully launched from the Space Shuttle Endeavor (STS-88) in December 1998 - MightySat 2 is a series of two to five vehicles (all with the same basic configuration) being built by Spectrum Astro, Inc., of Gilbert, Arizona.

MightySat 2.1 (first flight in the MightySat 2 series, also called Sindri), is a 300-pound satellite designed for launch from the Department of Defense-developed Orbital/Suborbital Program. MightySat 2.1 is now in the payload integration and testing phase; the integrated spacecraft was delivered to AFRL in February 1999. Launch is scheduled for mid-year 2000. Integration and testing is performed by military and contractor personnel in AFRL's new Aerospace Engineering Facility, located at Kirtland Air Force Base, New Mexico. On-orbit operations will be performed at Kirtland's Research, Development, Test and Evaluation Support Center.

The two classes of MightySat 2 payloads are Experimental Bus Components and Stand-Alone Experiments. Experimental Bus Components are essentially unproven hardware and include a Solar Array Concentrator (SAC), Naval Research Laboratory miniature Space Ground Link System Transponder (NSX), and Multi-Functional Composite Bus Structure (MFCBS).

SAC focuses more light on each solar cell, increasing the solar energy available. This reduces the number of cells needed to produce the same amount of power. SAC will provide the same power to DoD satellites as current arrays but at half the cost and weight and with one-third the number of solar cells.

NSX is a satellite communications unit developed by Naval Research Laboratory and is about 70 percent smaller and lighter than the current industry product.

MFCBS incorporates leading-edge technologies to demonstrate spacecraft bus flexibility and modularity. Its design includes an integrated thermal management system, robust structural integrity, high-attitude control accuracy, and precision three-axis stabilization.

Stand-Alone Experiment payloads manifested on MightySat 2.1 include a Fourier Transform Hyperspectral Imager (FTHSI), Quad-C40 processor (QC40), Shaped-Memory Alloy Thermal Tailoring Experiment (SMATTE), and Solar Array Flexible Interconnect (SAFI).

FTHSI is the only DoD space-based hyperspectral imager to use the Fourier Transform technique to discern spectrally unique objects. FTHSI illustrates the technical advantages of Fourier systems over dispersive hyperspectral imagers, in that it can record the full spectra without any time delay and can decouple the spatial and spectral signatures. Military applications of this technology include detecting and classifying hidden targets in the operational theater, while commercial applications include identifying and classifying environmental/crop damage.

QC40 experiment investigates the space radiation susceptibility of critical new forms of microelectronics through an advanced, high-speed processor. QC40 will also perform on-board processing and compression of the FTHSI raw data, increasing the number of images that may be downlinked to the ground station.

SMATTE investigates the actuation of a bi-modal composite sheet with respect to performing vibration isolation, structural control, deployment, and separation functions. SMATTE can change its physical properties, such as stiffness, damping, and shape, as a function of tailored thermal input signals. However, when SMATTE is heated above its transition temperature, it returns to its memorized shape.

SAFI incorporates copper leads embedded in a flexible, composite film reducing the weight and complexity of traditional hard wiring. It also is a leading step toward multi-functional bus technology.

Approximately 24 months following launch of MightySat 2.1, Flight 2 is slated to launch. It is planned to demonstrate formation flying, distributed aperture radar, laser and GPS ranging, Satellite Threat Warning and Attack Reporting, high-efficiency pulsed plasma thruster, and lithium-ion batteries. Additional technologies may include autonomous navigation and control and ultraspectral imaging.

MightySat 2's primary objective is to provide an affordable space-based platform for demonstrations of advanced space system technology. Demonstration of emerging technology will expedite transition of advanced capabilities from the lab bench to operational Air Force space systems.