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Legacy Systems: Keeping Older Satellite Systems Operating

By | January 1, 2008

      The launch of a new, more powerful satellite is exciting, as it opens the door to a range of new services and capabilities. But many satellite customers are quite satisfied with their current services and equipment, and as a result, satellite operators and ground equipment vendors alike must be creative in terms of offering next-generation solutions while at the same time maintaining and sustaining older legacy systems for established customers.

      For the satellite industry, many compelling reasons can propel companies to leap ahead and embrace new satellite technology, both in space and on the ground. Still, customers often are reluctant to abandon a satellite-based solution that has provided cost-effective and reliable performance year after year.

      When evaluating the pros and cons of sustaining legacy systems versus upgrading them or purchasing new ground and space systems, cost is the guiding force, says Andrea Maleter, technical director at Maryland-based Futron Corp. “In some ways, the biggest impediment to the adoption of new technology is concerns over the potential for this to impact insurance coverage either by raising rates or having large policy exclusions,” she says.

      Paul Welsh, vice president of business development at Pennsylvania-based Analytical Graphics Inc. (AGI) agrees that cost is always a factor in the decision-making process, and that while conversion/upgrade costs are highly tangible, benefits are harder to define. “Also, less visible to a decisionmaker are the costs of not upgrading — deferred efficiency improvements and prolonged capability shortfalls,” he says. “Too often operators think only about upfront costs without realizing the back-end implications of their decisions. Certain costs and uncertain benefits are at the heart of all upgrade/sustainment decisions. The challenges of sustaining legacy systems are personnel training and turnover as well as technical obsolescence. If the system is a unique or homegrown application, it can be expensive to maintain and extremely difficult to modify when new requirements are identified.”

      At the same time, a decision to discontinue the production of vital satellite components can negatively impact legacy satellite programs going forward. Parts that have been around for years can sometimes simply disappear, leaving a substantial void in the process.

      In July, BAE Systems announced that it would begin manufacturing radiation-hardened, field programmable gate array (FPGA) semiconductors for legacy satellite systems. BAE was the original equipment manufacturer of the FPGAs, which were produced from 1996 through 2006, and  is the only manufacturer of the new part. In resurrecting the component, BAE Systems identified a critical customer need, and its revival of the FPGA will enable producers of satellite payloads and instruments to avoid time-consuming and costly redesigns, BAE said.

      BAE has migrated all the requisite FPGA designs, processes and supporting software toolsets to its U.S. government-funded chip foundry in Manassas, Va., says Vic Scuderi, BAE Systems’ business area manager for space products. This facility is supported by agencies such as U.S. Defense Threat Reduction Agency, U.S. Air Force Research Lab and the U.S. Defense Advanced Research Projects Agency with the intention of advancing next-generation technology for space. BAE Systems is using the foundry for advanced technologies as well as insuring government programs can maintain legacy programs with older technologies. “In this instance, our customers and end users were demanding a specific spaceflight heritage part because without it, they faced millions in added redesign costs,” says Scuderi. “The bottom line is that whenever someone touches any circuit board, it has an immediate $7 million to $10 million impact on the satellite program in question.”

      Scuderi labels the process of mapping the graphical image of the legacy product and the successful transitioning of that product into the new software toolset domain as the real challenge. Once fabricated, the legacy chip will proceed through a rigorous qualification program. “Recent events in space including significant failures have triggered the creation of a new set of more rigorous component testing procedures and processes,” he says. “This activity has been driven by Aerospace Corp. acting on behalf of the government, and it will help to establish a trend with respect to legacy radiation hardened components going forward. There will be more pressure on satellite designers to justify the added expense of qualifying redesigned circuit cards using new components. Legacy products suddenly have a much bigger role in the design trade space.”

      System Performance Matters

      Sustaining legacy commercial and government systems involves a multi-layered approach, says Welsh. AGI does not directly sustain legacy systems, although its commercial off-the-shelf software products often are used to provide additional functions and capabilities, a very important element in the Pentagon’s master plan for space superiority. This extends to all space situational awareness applications, along with offensive and defensive counter-space measures. AGI software can be found at the U.S. Air Force’s 22nd Space Operations Squadron and at the Naval Satellite Operations Center, where AGI business partners Applied Defense Solutions and Maxim Systems have integrated AGI software to support the geostationary flight dynamics workflow for operations.

      “The [Space Operations Squadron] uses AGI products for the Air Force Satellite Control Network scheduling,” says Welsh. “In particular, AGI’s STK/Conjunction Analysis Tools evaluates all routine collision avoidance data for the approximately 80 [Department of Defense] satellites controlled by the [Satellite Control Network]. This can turn around this data in minutes when it previously had required days,” he says.

      AGI stresses user friendliness to reduce headaches during a transition. When the Naval Satellite Operations Center needed a much more accurate orbit determination system, a new graphical user interface system was created for maneuver planning, orbit determination, product generation and collision avoidance. In addition, the system was automated to produce a variety of products necessary for the operations of the satellites, says Welsh.

      Customers Can Get Too Attached To Software

      While you might think that companies that depend upon satellites for their cash flow would be quick to embrace the latest versions of software, this often is not the case. Many customers wait years before taking advantage of new software products simply because they are happy with the release they have.
      “Customers are happy with the systems that we provide, so they tend to avoid the software upgrade process just to access new features, even though this new software is free under our software support program,” says James Kramer, director of commercial command and control systems for Maryland-based Integral Systems Inc. Upgrades occur usually within three to five years, driven either by a satellite fleet expansion or by hardware obsolescence. “In the case of hardware obsolescence, the fact is that as quickly as hardware technology evolves today, maintaining legacy hardware can often be more economically challenging than buying modern, more capable hardware,” says Kramer. “When performing such a hardware refresh, customers often will upgrade to the latest Integral Systems software available at the time of the refresh.”

      Synchronizing satellites, ground infrastructure and support staff on the ground can be a challenge, too. While a typical geostationary satellite has a lifespan of 15 years, the experience curve on the ground might be considerably shorter. “Our people can help to sustain these legacy systems as well as mentor a customer’s less experienced personnel in the operation of these legacy systems,” says Ed Larson, president of California-based Legacy Engineering LLC, which specializes in providing senior technical and management professionals who have retired from the aerospace and defense industries to consult on older systems. “Often times these individuals are supporting systems that they were involved with when they were full-time direct employees.”

      Companies often are challenged to identify certain key competencies and skill sets that are fundamental to continued support of their legacy systems. This involves identifying the right skill sets at a time when there are not enough experienced and knowledgeable professionals to go around and when the outside veteran talent in question might not be inclined to commit to a full-time schedule. “HR [human resources] organizations and hiring managers need to be flexible and creative as they staff their teams,” says Larson. “For example, some of our people are interested in working a reduced schedule, say three days a week. However, the knowledge, history and productivity they bring to the team can far outweigh their less-than-full-time availability.”
      Supporting the proposal and development phase of new systems or upgrades to legacy systems also is important, says Larson. “In some cases, the individual is familiar with the resident technology and processes,” says Larson. “In other cases, the company is looking for an outside perspective and we can provide that, too.”

      Extending Life Via Inclined Orbit

      When it comes to sustaining legacy systems, satellite operators for decades have used life-extending techniques to maximize the value of their on-orbit assets. Placing a geostationary satellite in inclined orbit — what was once called the “Comsat maneuver” — involves the elimination of north-south station keeping, and yields a predictably expanding figure eight. “This extends the on-board fuel and thus the life of the satellite,” says Maleter, who estimates that there are probably 60 to 100 commercial communications satellites now operating with some degree of inclined orbit. “The initial challenge is in deciding how early in the satellite’s life to start this operation, since it requires that Earth stations accessing the satellite be able to track the figure eight motion. Smaller or non-attended antennas typically do not have tracking. How long an operator keeps a satellite in this mode of operation depends on the spacecraft’s role, overall health, service requirements and other factors.”

      Inclined orbit satellites often are used for trunking services — which can include TV relay as well as telephony — between large, tracking antennas. This can require upgrades to ground equipment as a result of changing user applications in particular and the desire to squeeze more out of available bandwidth, says Maleter, and it really has little or nothing to do with the satellite in question. “Upgrading to MPEG-2 or MPEG-4, for example, has much more to do with wanting more capacity than with problems related to satellite life,” she says. “In general, cost is king, but the key is whether costs can be recouped through extensions or expansions that add new customers or add value to old customers.”

      Another technique for extending the life of satellites on orbit involves using fuel equalization accomplished by fuel rebalancing in satellites with multiple fuel tanks. According to a research paper published in the Journal of Spacecraft and Rockets in 2007, a procedure known as thermal gauging can be used to determine how much propellant is contained in the tanks  and rebalance the load using on-board heaters to move the remaining fuel. In essence, the thermal pumping solution entails heating up fuel tanks containing more fuel and keeping the emptier tank cooler so that the helium gas in warmer tanks eventually pushes the liquid fuel into the emptier tank.

      The research was conducted using a pair of satellites in geostationary orbit that were decommissioned in 2003. “Publication took sufficiently long, so that the benefits of that specific piece of work have already been exhausted — the satellites in the paper were eventually decommissioned, but fortunately, after maximizing the revenue from them thanks to the propellant rebalancing and gauging work,” says Steven Collicott, a professor at Purdue University’s School of Aeronautics and Astronautics, and coauthor of the paper along with two engineers from Lockheed Martin Space Systems Co. “We are pursuing additional opportunities to deliver propellant gauging and rebalancing to satellite operators and to advise in the design efforts of new satellites. Most new satellites launch have one large fuel tank, so rebalancing needs will likely fade away, but propellant gauging needs will remain.”

      Collicott estimates that the overall engineering costs amount to less than a day’s revenue from a modern commercial geostationary satellite, and commercial satellite operators who want to explore this propellant gauging and rebalancing solution can do so via Comsat Technical Services. “Owners and operations should begin to address the gauging question with us as soon as the slightest uneasiness with gauging data emerges,” he says. “The sooner we start on the effort the better we can deliver results and options for the operators and the sooner they can be confident in revised end-of-life schedule predictions. Waiting to start does not improve results and the cost of our analysis (can be) overwhelmed by the expense of a surprise propellant depletion in a revenue-generating satellite.”

      According to Boris Yendler, senior thermal system analyst at Comsat Technical Operations/LMMS and coauthor of the report, 10 per cent of existing geostationary satellites could benefit from this solution. “Our technique could be applicable not only to [geostationary] satellites, but also to [low-Earth orbit] satellites as well,” he says, who adds that a plug-and-play software solution is being developed based on this research. “We are in negotiation right now with a company to make a software package which can be sold to customers to estimate propellant remaining.”

      The decisionmaking process surrounding the acquisition of a new system or solution is complex. Cost may drive the decision, but when one is attached to a proven piece of satellite-based hardware or software with an extremely reliable track record, taking the next step can be very hard to do indeed.

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