In a world seemingly gone mad at times, our nation’s and our allies’ armed forces and government agencies are, nowadays, even more dependent upon the intelligence, surveillance and reconnaissance data beamed to them by various MILSATCOM satellites. Retasking flexibility, observation without detection, and the delivery of near-instant communication and data are just three reasons for the continuance of satellite build programs that result in saved lives and operational successes.

The companies involved in such endeavors range from extremely large in size to those with just a few professionals staffing their efforts. Some are names we all are quite familiar with, as their satellite offerings are just one portion of their overall manufacturing and technology offerings. Others you may never have heard of, but they are as equally important in producing viable products to aid MILSATCOM efforts. This issue, we enter the environs of Comtech AeroAstro.

With locations in Ashburn, Virginia, and Littleton, Colorado, Comtech AeroAstro brings more than 20 years of experience in small satellite development to the marketplace. The Company has executed contracts for the development of seven complete spacecraft, from the ALEXIS spacecraft launched in 1993, to current work on the JMAPS spacecraft.

The end customers have included U.S. Government agencies and laboratories such as the Naval Research Laboratory, DoD Space Test Program, and Los Alamos National Laboratory, as well as universities conducting critical national research, such as at the Massachusetts Institute of Technology and Boston University. With continued investment into advanced technologies, such as plug-and-play, spacecraft capabilities are ever expanding into a broader set of product offerings, mission areas, and the acquisition of new customers.

It Takes Experience

In 2008, Paul Lithgow was named President of Comtech AeroAstro, Inc. He was previously the Company’s COO. Before joining AeroAstro, he served as the Director of Advanced Concepts at Radyne and led the Advanced Programs Division at Spectrum Astro until August of 2004. Mr. Lithgow has more than 25 years of management and technical experience and served in the U.S. Air Force in airlift, acquisition and technical intelligence positions. He is also a Member of the Board of Directors for Agape Youth Ministries, developing a program and building facilities to serve at-risk teens.

The Senior Vice President and General Manager, Commercial, Civil, International Programs for the Company is Stanley O. Kennedy, Jr. He executes all program activities, which include the Space Systems and Space Product development, to which he is acutely tuned with more than 26 years of experience in aerospace engineering that includes mission domain knowledge in military, intelligence, civil and commercial markets. He was the Senior Program Managerfor small satellite systems and concepts for Lockheed Martin Space Systems Company before joining Comtech AeroAstro. Providing direction and oversight for the content and quality of the Company’s engineering product, as well as design reviews, documentation and analysis, is Dean Roukis, the Vice President of Engineering. He joined the Company in 2005 as Chief Mechanical Engineer and brought more than 27 years of technical and management experience into the company. He previously had served as Principle Engineer in Satellite Operations at Intelsat where he was responsible for in-orbit power systems operations of 20+ geosynchronous satellites.

Rounding out the executive team is Debra Latter, Vice President, Finance and Contracts. With 32 years of financial management, she is responsible for Comtech AeroAstro’s Sarbanes-Oxley implementation and government compliance. She is a member of the AICPA.

Steven Schenk, the Senior Vice President and General Manager, Defense Programs, packs in more than 20 years of experience including the responsibility of being the Program Manager for the NASA Goddard GLAST space vehicle and DARPA Streak space vehicle programs during his time at General Dynamics. With Comtech AeroAstro, Steve executes on all emerging defense programs and has also functioned as the Company’s Program Manager for the ORS Multi-mission Modular Space Vehicle Preliminary design phase program, developing a flexible spacecraft design that incorporated plug-and-play technologies.

How’s This For Heritage?

Bus Stops
There is not much one can do to produce a satellite without a viable bus. For Comtech AeroAstro, their Astro 200 bus series handles configurations in the ~200kg total mass range, which can be accommodated by a variety of launch vehicles, including Minotaur I, Minotaur IV, Pegasus, Falcon 1e, Atlas V and Delta IV ESPA. Payloads of up to 85kg in mass and 100W in power can fit into the standard interface of the Astro 200 without modification. The Astro 200AS is an enhanced performance version of the Astro 200 with improved attitude knowledge and control, jitter, additional X-band downlink capability, improved timing accuracy and a longer mission life. The enhanced version was initially developed for the U.S. Navy’s Joint Milli-Arcsecond Pathfinder Survey (JMAPS) mission. STPSat-1 and STPSat-2, launched in March of 2007 and November of 2010, respectively, were based on the Astro 200 core design.

The Company’s Antares bus offers a 500kg space vehicle mass range (spacecraft + payload) that’s been designed to maximize payload accommodations by optimizing payload mass (up to 200kg), payload power (400W on-orbit average and 800W peak) and payload volume (Minotaur I 61-inch fairing). Antares meets the launch requirements for the same list of Astro bus compatible launch vehicles. The bus uses standard, open architecture, non-proprietary interfaces, a 100 percent Space Plug-and-Play Avionics (SPA) compliant network, and is 100 percent SPA-SpaceWire compatible that supports 200 Mbps data rates on orbit.

Antares can operate in a variety of LEO and HEO orbits with a full range of altitudes and inclinations. No changes in transitioning from a low radiation LEO environment to a high radiation LEO environment are needed, thanks to the S-class quality parts and solid aluminum panels. The hinged hexagon structure allows for efficient, internal component access at all program states, all the while minimizing parts count. Propulsion is easily added for longer mission durations, orbit raise and maneuvering, as well as attitude control.

ALEXIS

Comtech AeroAstro’s first spacecraft, Array of Low Energy X-ray Imaging Sensors (ALEXIS), was built for the Los Alamos National Laboratory. The satellite was launch-ready three-and-one-half years after concept and was launched in April 1993 on a Pegasus booster. The atellite operated on orbit for more than 12 years, far beyond its six-month design lifetime and surpassed all mission requirements and expectations until its final decommissioning in 2005.

The ALEXIS spacecraft accommodated two payloads: 1) the soft X-ray experiment, also called ALEXIS, was a novel set of wide-angle, normal incidence telescopes, which scanned half the sky every satellite rotation; 2) BLACKBEARD, an accompanying instrument, was a broadband receiver and digitizer designed to study ionospheric propagation in the 25-175 MHz band. The spin-stabilized spacecraft’s bus comprised only 40 percent of the total satellite mass (45kg bus mass, 11 kg total mass). The bus provided 50 Watts of 28V power to the payload while consuming only 10 Watts of power itself. Attitude could be determined at any instant in post-processing to ±0.25 degrees.

Payload data were recorded in a Comtech AeroAstro-supplied 96MB spacecraft mass memory at mean rates of 10 kbits/second, with peak rates reaching in excess of 100 kbits/second. The ALEXIS system employed a “store-and-forward” architecture to pass tracking, telemetry, and control, and data between the spacecraft and a single ground station at Los Alamos. Commands were uplinked at 9600 bits/second and data were downlinked at 750 kbits/second via a steerable two-meter dish. Comtech AeroAstro designed and built the spacecraft bus and the ground station, as well as supported the launch and ground operations activities.

STPSat-1
Developed for the DoD’s Space Test Program (STP), STPSat-1 is the first STP satellite built specifically to exploit the Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA) launch capability. Comtech AeroAstro’s role as prime contractor for the mission included spacecraft design, fabrication and assembly, payload integration, system test, launch vehicle integration, and post-launch support. This Class C single string spacecraft hosted two Space Experiment Review Board (SERB) experiments: the Spatial Heterodyne Imager for Mesospheric Radicals (SHIMMER); and the Computerized Ionospheric Tomography Receiver in Space (CITRIS), both provided by the Naval Research Laboratory (NRL).

Successfully launched in March 2007 on the only ESPA launch to date, STPSat-1 was the first, and only, ESPA rideshare spacecraft developed by a U.S. contractor. STPSat-1 was designed for a one-year mission life, but operated successfully until its decommissioning in October 2009, providing valuable mission data for more than two-and-one-half years.

STPSat-1 is a highly capable, three-axis stabilized space platform that met the demanding technical requirements for the mission and launch environment. Packaged in the highly constrained ESPA envelope (~2 ft. × 2 ft. × 3 ft. in volume and ~180kg mass), STPSat-1 served as a pathfinder for developing a highly capable microsatellite supporting multiple space payloads as well as for the first ESPA integration cycle that included range safety approvals, coordination of multi-vehicle integrations, deployments and timelines, and multi-vehicle mission operations out of the USAF RDT&E Support Complex at Kirtland AFB.

STPSat-2 / STP-SIV
The STP-SIV program supports the Space Test Program’s goals to maximize space flight opportunities for Space Experiment Review Board (SERB) experiments. The STP-SIV bus design evolved from Comtech AeroAstro’s experience as the prime contractor for STPSat-1, launched aboard the first ESPA (Atlas-V/STP-1) in March of 2007. Comtech AeroAstro simplified and enhanced the STPSat-1 design for the STP-SIV program to improve reliability, enhance mission flexibility and orbit range, and to provide the standard payload interface that is critical in supporting the maximum possible number of experiments. Also developed were high fidelity development and test plans, complete operating procedures including the bus content for the Payload User’s Guide, and a detailed cost baseline. Such efforts will allow this bus design to be reproducible for a diverse set of mission options.

Each vehicle is designed to operate over a wide range of LEO orbits and to be compatible with a large variety of launch vehicles (see Bus Stop), including an EELV Secondary Payload Adaptor (ESPA) rideshare. Comtech AeroAstro’s role was to design, build, and integrate the SIV bus under subcontract to prime integrator, Ball Aerospace. The first SIV bus, for the STPSat-2 mission, was delivered to Ball in December of 2008 for payload integration and was launched on a Minotaur IV from Kodiak, Alaska, in 2010.

ORS MMSV: Multi-Mission Space Vehicle
Under the Operationally Responsive Space (ORS) Multi-Mission Space Vehicle (MMSV) Preliminary Design study, executed from October 1, 2008, to February 1, 2009, Comtech AeroAstro designed a reconfigurable, multi-mission, rapid response space vehicle capable of hosting a variety of missions and payloads. The design focus was on Electro-Optical, Space Situational Awareness (SSA), and Synthetic Aperture Radar (SAR). The “core” bus design evolved from a set of approximately 30 Design Reference Missions, in which cost, schedule, technical performance, and logistics footprint were all assessed against Key Performance Parameters, which were ranked in order of importance with government input and feedback.

The final design met the stringent ORS cost ceiling (<$40M for recurring vehicles) and schedule goals by implementing space vehicle modularity at the component level. This required the implementation of plug-and-play architectures and used a non-exquisite technical performance philosophy that allowed new and advanced technologies to be fielded in a rapid timelines of less than six months, versus the typical 18 to 24 month timeframes.

The ORS MMSV design, which is an implementation of Comtech AeroAstro’s Antares bus design, accommodates a wide variety of mission configurations / scenarios in the <460kg space vehicle (spacecraft + payload) mass range. The bus is designed to maximize payload accommodations by optimizing payload mass (up to 200kg), payload power (400W on-orbit average and 840W peak), and payload volume (Minotaur I 61-inch fairing) at LEO inclinations ranging from 30 to 97 degrees and altitudes from 350-800 km. The ORS MMSV design extensively uses standard, open architecture, non-proprietary interfaces, which allows for rapid reconfiguration, flexibility, and robustness for accommodating a large range of missions or payload types.

HETE
Comtech AeroAstro built the High Energy Transient Experiment (HETE) spacecraft for the Massachusetts Institute of Technology (MIT) with scientific cooperation from teams in the United States, France, and Japan. The mission for this spacecraft was the detection and observation of high-energy events in the gamma ray, X-ray, and UV spectra. HETE, a pathfinder for the NASA University Explorer program, was launched on a Pegasus XL on November 4, 1996, with the SAC-B satellite. It was lost due to a launch failure and rebuilt as HETE-2 (based on the original design), which was successfully launched in 2000.

The Company supplied the spacecraft bus (55kg bus mass, 120kg total mass) and ground stations, and performed all payload integration and testing. In flight, the spacecraft oriented the fixed solar arrays toward the sun with instruments pointing in the anti-sun direction. Its communications system used a 230 kbit/second data downlink rate and a 7.5 kbit/second uplink rate. The power system supplied 67W average power at a nominal 28V to the payload.

TERRIERS
Comtech AeroAstro supported Boston University on the design and fabrication of the spacecraft and ground station for the Tomographic Experiment using Radiative Recombinative Ionospheric Extreme ultraviolet and Radio Sources (TERRIERS) remote sensing spacecraft. This low-cost, fast-paced program was part of the Student Explorer Demonstration Initiative—sponsored by the Universities Space Research Association—and a precursor to NASA’s University Explorer program. The TERRIERS’ mission was to demonstrate global ionospheric tomography (imaging by sectioning) and to use the techniques to study ionospheric / thermospheric processes. The satellite was spin stabilized and had a mass of 121kg. The satellite bus provided 59W orbital average power. TERRIERS was launched on May 17, 1999.

Current Endeavors
Comtech AeroAstro is deeply involved in the Joint Milli-Arcsecond Pathfinder Survey, otherwise known as JMAPS, a Department of the Navy space-based, all-sky astrometric bright star survey. The satellite is scheduled to launch in 2015 and uses the Astro 200AS bus to host the instruments over the projected three-year mission life. Comtech AeroAstro has been a participant in the JMAPS mission development since 2005, building on work the Company originally conducted for the Air Force Research Laboratory (AFRL) and DARPA. Prior risk reduction efforts by Comtech AeroAstro have demonstrated that the demanding technical requirements for JMAPS can be met with a microsat-class space vehicle (<200kg). Work is being closely tied in with the NRL and the U.S. Naval Observatory (USNO) efforts to provide a proven bus that incorporates extraordinary jitter control, significant software reuse, and use of high-TRL (Technology Readiness Level) components.

One of the Company’s most recent developments is their new approach to support Low-Earth Orbit (LEO) Space Traffic Control. This approach is called the Payload Alert Communications System (PACS). PACS provides low-cost, low-size, weight and power (SWAP) position, velocity, time information along with low-data rate Host vehicle health and status reporting using the firm’s patented Code Phase Division Multiple Access (CPDMA™) waveform. Comtech AeroAstro uses a unique tagging, tracking and locating device, along with the existing GPS system and Globalstar data-messaging infrastructure, to provide PACS services to users.

Comtech AeroAstro’s PACS significantly reduces the manpower required to monitor and develop SSA associated with LEO spacecraft of all shapes and sizes. PACS leverages the Comtech AeroAstro-developed Sensor Enabled Notification System (SENS) technology developed for terrestrial tagging and tracking to provide the customer an easily integrated tool. This data availability can be critical during post-launch initialization and anomaly resolution, since the availability or lack of information for extended periods can be the difference between rescue and loss of an orbiting asset. PACS uniquely leverages the existing SENS, GPS and Globalstar infrastructure for autonomous reporting of position, velocity, spacecraft ID and limited health and status data messages to provide the customer assured SSA in the densely populated LEO environment.

The primary objective of PACS is to provide round-the-clock state-of-health and state-vector data, independent of ground system infrastructure and constraints. Data latency timelines (minutes) are orders of magnitude faster than those accomplished by existing ground assets (daily to weekly).

Spatial resolution of the data is substantially greater than commonly used radar or UHF / VHF communications system ranging methods. PACS also provides a valuable low data rate alternative communication path to the spacecraft owner, as the successful transmission probability with link closure (>90 percent) far exceeds traditional ground stations.