Military satellite designers rely on increasingly complex layers of software, and this means more vulnerabilities are lurking in space and on the ground. As more emphasis is placed on everything from real-time video transmissions to cyber warfare, the software that sustains satellite network performance becomes an even greater cause for concern. It must be even more robust, more reliable and more survivable.
Advanced, next-generation military satellite systems and networks require more sophisticated software systems and processes to support and operate them. Thus, when discussing military satellite research, development, test, and evaluation, one cannot turn a blind eye to the software dimension, especially at a time when there is a growing emphasis throughout the U.S. Department of Defense on cyber warfare, Web-enabled space operations and highly automated — even totally autonomous — satellites and ground elements.

Software becoming More Complex

The reliance that the U.S. military is placing on software — and the potential problems that can arise — have been highlighted recently by the revelation that the amount of code that will be required to support the U.S. Army’s Future Combat Systems (FCS) program has more than doubled in the past five years. FCS, the most ambitious weapons system being developed by the Army, will connect manned and unmanned systems via a common network, providing real-time digital communications and surveillance data provided by next-generation spacecraft directly to warfighters. Recent press reports have indicated that the number of lines of code needed for the system has jumped from 33.7 million to 63.8 million, with a corresponding jump in costs.
Such growth has led the U.S. Government Accountability Office (GAO) to look closely not just at military space acquisition activities but also the overall software environment in the process. According to Art Gallegos, GAO assistant director, it has been during system integration efforts where key problems have been uncovered. “The [Department of Defense] has had great difficulty in fielding ground control and satellite flight software on time and within cost in past space programs,” he says. “Most recently, the flight control software for Space Based Infrared System now poses significant challenges to the contractor (and) the [Department of Defense].” At a more strategic level, the GAO has noted that the Pentagon does not have an overall investment strategy that could help identify priorities for funding, needs to address capacity shortfalls in human capital and other areas such as cost estimating, and should revise policies supporting space to incorporate best practices.
Congress also has taken notice of the issue. “Congress continues to be concerned about the high costs, the requirements process and the priorities that have been established in the space acquisition process,” says Sen. Susan Collins (R-Maine), a member of the Senate Committee on Armed Services’ Emerging Threats and Capabilities subcommittee. “In many instances, capability decisions are made too quickly and on the basis of a specific technology rather than as a result of evaluating a range of technologies that could be used to provide a desired capability. Programs have been terminated early to free up funding for the next-generation satellite, and new programs have been started with immature technologies and without clear and feasible requirements. This has, in fact, delayed programs and has made space system architecture, such as satellite systems, vulnerable to capability gaps. Recognizing these challenges of designing and launching satellites, [the Department of Defense] the Air Force, the Navy and the intelligence community have recently taken steps to better focus on the requirements process and the development of a sequential approach to improving capability. This back-to-basics approach is off to a good start, but more remains to be done to improve the acquisition of space systems. The military and the intelligence community must work together to identify opportunities for more joint programs that support both communities.”
The laser-enabled Transformational Satellite Communications System (TSAT) and its accompanying TSAT Mission Operations System also have seen an increase in code, but not nearly at the rate for FCS. The Mission Operations Systems team initially planned for just more than 3 million lines of code but has seen that number grow to around 5.3 million lines today, while the TSAT space segment relies on about 2.7 million lines of code, although that line count estimation will only be finalized once the winning contractor for the space segment is selected — either Boeing Satellite Systems Inc. or Lockheed Martin Space Systems Corp.
“The TSAT program will rely on highly sophisticated technologies including an on-board router for net-centric operations and laser communications systems for gigabit-class intelligence, surveillance, and reconnaissance data relay,” says a spokesman for the Air Force Space and Missile Systems Center’s Military Satellite Communications Systems Wing at Los Angeles Air Force Base. “Due to the early investment in [research and development] funding for TSAT, the program has successfully demonstrated the maturity of its key technology elements prior to the commencement of the system’s preliminary design phase. … The investment in TSAT through FY08 has been on maturing the critical technologies and preliminary system designs prior to committing to the program. All key TSAT technologies have been appropriately demonstrated in a relevant environment.”
The Air Force is confident that TSAT is progressing, and an independent technology readiness assessment has verified that TSAT technologies are at the appropriate level of maturity, a key milestone before the program enters into the preliminary design phase, the spokesman says.
While GAO has reported that the TSAT acquisition effort is making an effort to apply acquisition best practices, GAO’s biggest concern with the program is system integration. Critical technologies have been determined to be at Technology Readiness Level 6 or higher, a designation means that a system/subsystem model or prototype has been demonstrated in a relevant environment on the ground or in space. “According to the program’s independent technical reviews, TSAT is ready to proceed …,” says Gallegos. “The hard part now will be to seamlessly integrate the new technologies so they all perform as a cohesive system.
Despite the status of the technology development, TSAT has suffered considerably recently in terms both of budgetary cutbacks and further extensions of its initial launch date. Funding for the program to date consists only of research and development funds, and through the end of fiscal year 2007, TSAT development costs exceeded $2 billion, according to Gallegos. The Air Force is seeking just $843 million for the program in fiscal 2009 and $6.6 billion over the next five years, about $4 billion less than initially planned, and the deadline for design and development of the five satellites has been pushed to July.
But next-generation satellite development and deployment continue to remain a key part of the U.S. military’s plans, as airborne intelligence, surveillance and reconnaissance assets are key elements in operations in Iraq and Afghanistan which results in the offloading of high quantities of data in theater and back into the processing centers in the United States. Thus, the Pentagon is seeking a large number of simultaneous, high data-rate links for the platforms via programs such as TSAT and Wideband Global Satcom. Multiband capabilities also allows many users to access the same data streaming from any given asset via the Global Broadcast System now transmitted over the U.S. Navy’s UHF Follow-On satellites and the Wideband Global satellites.
“The most significant trend in the Air Force [research and development] funding for space programs can be seen in our back-to-basics approach to space acquisition,” says the Air Force spokesman. “This initiative promotes a renewed emphasis on increased discipline in the development and stabilization of requirements and resources, engineering practices, and management as well as a more deliberate acquisition planning strategy. One key tenet of this back-to-basics approach is an increased emphasis on early technology development through increased [research and development] investments to ensure mature technology is available for our production systems.”

Search for New Modeling Processes

NASA’s Goddard Space Flight Center has studied the implications of Operationally Responsive Space on flight software architecture as well as what development tools are needed for a rapid spacecraft development effort, says Jonathan Wilmot of Goddard’s Aerospace Technology, Software Systems. Specifically, the work looked at the impact of a so-called core flight software system architecture and the integrated development environment on Operationally Responsive Space. “To construct, test and fly a satellite in the timeframes requires software that is essentially reused and/or has a high degree of automated code generation and automated test. The [core flight software] architecture is designed for component reuse and supports automatic configuration and code generation at the component level via the [integrated development environment],” he says. “The message of the paper was to show the applicability of the [core flight software] architecture to the goals of the initiative.”
The existing software modeling process might not be suitable given stringent Operationally Responsive Space requirements, says Wilmot. “The existing flight software system modeling process would need to be enhanced to support the [Operationally Responsive Space] needs for rapid code configuration, generation and test,” he says. “… A flight software architecture would need to support the modeling environment. A benefit of a component architecture is that a model for each component can also be included in the component library. When the spacecraft is being developed, the model for the component can be automatically extracted from the library and included in the overall system model,” he says.
Goddard is working with personnel at U.S. Air Force Research Laboratory to integrate core flight software and plug-and-play software modules with SpaceWire network interconnects, an Ethernet-friendly standard intended to help replace existing shared bus architectures aboard satellites with on-board switched networks and the use of standard protocols such as Internet Protocol (IP). It furthers the cause of Web-enabled space operations, among other things. The extensive use of Web-based tools was one of the groundbreaking dimensions of the TacSat-2 deployment, including one which enabled access to historical telemetry data.

Internet-Enabled Satellite Operations

The TacSat-2 mission was designed to demonstrate, among other things, the tactical advantages of Operationally Responsive Space platforms including theater-specific orbits and elements that stressed user-friendliness and IP-based operate-from-anywhere capability. On the ground, tapping into the existing Modular Interoperable Service Terminal was another objective because these terminals are deployed as the primary means for conducting unmanned aerial vehicle operations.
As part of the mission, GeneSat-1, a NASA-funded project, opened a new chapter in Internet-enabled satellite operations in addition to its novel distributed command and data handling capabilities. It was one of several picosatellites which flew with the TacSat-2 mission. A team from Santa Clara University in California was responsible for all GeneSat-1 mission operations and the ground command and control network, says Chris Kitts, an associate professor of mechanical engineering and director of the Center for Robotic Exploration and Space Technologies, a multi-institution consortium or academic institutions at the NASA Ames Research Park. Genesat-1 was designed to conduct biological examinations to look for genetic changes in bacteria during spaceflight as part of a way to better understand the biological effects of the spaceflight environment and the impact on long-duration crewed space missions and space tourism. “The Genesat-1 network was all Internet based, extremely flexible and easily and quickly reconfigured for multiple users,” says Kitts. “It allowed for very inexpensive and operate-from-anywhere use while still being secure.”
Prior to GeneSat-1, the Santa Clara team performed the first live plug-and-play rapid integration and test demonstration in 2006. This was funded via the Air Force Research Laboratory’s university nanosatellite program. “We plugged in a component that we had never seen before our avionics backbone and had it integrated and in use within a few minutes,” says Kitts. “We were also able to arbitrarily cross-strap components from two different satellites that had been independently developed using our avionics specification. Our real objective is to develop what we call ‘composable missions’ where you not only plug in your satellite components, but you literally plug in your entire algorithm set. We have demonstrated aspects of this already with GeneSat-1, Sapphire and other robotic missions in which generic algorithms to handle health management are plugged into mission-specific models in order to detect, diagnose and resolve anomalies. We are actively researching extensions to this work to develop algorithms for command planning and payload processing.”
This is why all eyes are on the software. Risk reduction and integration are not easy to accomplish, so it helps to get it right the first time, line by line. And the demands of Operationally Responsive Space do not help matters, since the effort is all about responsiveness with an emphasis on speed. That requires faster processing, and more automation. Add it all up and you can see that this is not an easy undertaking by any means.