Increasing Space Situational Awareness

Written by Erin Flynn Jay

MSMF 2009 Volume: 2 Issue: 6 (November/December)

The Space Based Space Surveillance System (SBSS) mission is to provide space situational awareness through the timely detection, collection, identification and tracking of man-made space objects to enable the joint functional component commander for space, in support of global strike task forces, to find, fix and track deep space and near-Earth resident space objects. SBSS will operate in conjunction with the Space Surveillance Network (SSN) to support spaceflight safety, ensure space catalogue completeness, warn of on-orbit separations and maneuvers, and provide indications and warnings of potentially hostile space events.

As this issue of MSMF was going to press the Space and Missile Systems Center public affairs office reported that an issue with the Minotaur IV launch vehicle, which affects the entire MIV fleet, resulted in an indefinite delay of the first SBSS launch. The requested fiscal year 2010 funding in the DoD budget for SBSS program is $80.6 million for Block 10 and $97.7 million for follow-on; total requirement is $178.3 million.

SBSS will have a single electro-optical sensor capable of detecting visible light. SBSS will also provide the position of numerous space objects from satellites to orbiting debris, and identification of specific objects of interest. Col. J.R. Jordan, vice commander, Space Superiority Systems Wing, Air Force Space Command’s Space and Missile Systems Center, said the order of magnitude improvements will be:

• Probability of event detection (space launch, satellite maneuver)—3 times better

• Time to detect events—2 times better

• Sensitivity—2 times better

• Capacity—10 times better

The Air Force intends to begin improving the constellation’s capabilities with the third SBSS satellite. SBSS data will be sent to the Joint Space Operations Center (JSpOC), where it will be integrated and used by combatant commanders.

FREEFLYER PROTECTING SATELLITES

There are different hardware and software solutions to protect U.S. military satellites. FreeFlyer is a commercial off-the-shelf (COTS) tool developed by a.i. solutions and used by DoD, NASA, NOAA and commercial satellite operators for flight dynamics mission analysis and satellite operations. FreeFlyer is used daily in protecting satellites from collisions with other spacecraft and orbital debris.

FreeFlyer is the backbone of the Goddard Space Flight Center Conjunction Assessment System (CAS)—an automated operational system that analyzes daily spacecraft conjunction screening data from the JSpOC, assessing the comprehensive collision threat to a given satellite, said David McKinley, project engineer for a.i. solutions. The FreeFlyer-based CAS currently provides situational awareness for over 100 DoD, NASA, NOAA and commercial spacecraft— modeling the space debris environment, performing collision risk assessment analysis and analyzing collision risk mitigation options, such as maneuvering active satellites out of the way of a potential collision threat.

“Future enhancements to the CAS will include adaptation of a service orientated architecture, which will improve reporting efficiency and situational awareness, while allowing operators to add additional spacecraft to their constellations without increasing operational costs,” said McKinley. Other enhancements include incorporating “data fusion” techniques, which consider the varied individual metrics necessary to create a clear space situational awareness (SSA) picture (e.g. miss distance, collision probability, orbit determination solution quality) and “fuse” them into a single quantifiable threat index level that easily conveys the level of risk to satellite operators.

FreeFlyer 6.6, due out this fall, will also provide users with an advanced orbit determination engine, allowing for greater flexibility and the high accuracies necessary to determine the orbits of thousands of space objects with greater precision.

AGI’s desktop software applications, engine and components technology enhance SSA and allow users to maintain assured space protection. The software dramatically improves speed, accuracy and efficiency. Based upon highly precise time-dynamic geometrical modeling of objects in space, their tools are equally applied to engineering design and analysis studies and to day-to-day mission operations. “Some of our capabilities include: orbit determination and satellite catalog maintenance, satellite maneuver detection, resident space object tracking, rapid conjunction analysis, on-orbit debris modeling, new foreign launch analyses (characterizing nominal and anomalous mission events and trajectories), rendezvous and proximity operations and direct ascent antisatellite (ASAT) analysis,” said Robert Hall, AGI technical director, Space Superiority.

STK ANALYZES SPACE OBJECTS

As the number of tracked space objects grows (currently more than 13,500 in the public space catalog), the ability to rapidly perform accurate conjunction assessments becomes more critical. “Using our STK Professional Edition and STK/Conjunction Analysis Tools [STK/ CAT], our customers can ensure that high-priority assets remain protected. While there are many organizations able to run one object against the entire space catalog to predict collisions, AGI technology performs rapid full-catalog conjunction assessment, analyzing all space objects against all other space objects, using commercially available PC hardware,” said Hall.

To accomplish this, AGI used ephemeris data from the space catalog with a service manager and a single 64-bit 32 GB RAM dual quad-core processor COTS personal computer (about $4,000). Using this platform, AGI completed two approaches: one using multiple copies of existing AGI desktop STK/CAT, and a custom application they built leveraging their AGI components technology. “With both approaches, we were able to demonstrate successful completion of five-day runs using approximately 12,000 satellites [using ephemeris files] in under an hour. Additional plans for expansion and further efficiency gains as the catalog grows are under way,” said Hall. “Taking advantage of this rapid capability, we have built a Web-based database management system to provide automatic satellite operator conjunction notification and allow for clients to mine the conjunction data for further analysis. This will eventually enable operators to fully study conjunctions as well as plan potential satellite maneuvers to mitigate the possible threat of collision.”

Any attempt to build and maintain a comprehensive understanding of space objects must include the modeling of space debris. AGI software’s complete breakup modeling environment simulates debris generation events (collisions, ASAT tests, rocket body breakups, etc.) and accurately models the debris field evolution. The simulation technique employs an automated trajectory design that leverages a full force model and user-defined impulsive forces with numerical integration, said Hall. By using impulsive forces to initiate the debris dispersion under user-controlled models, large numbers of debris trajectories can be rapidly generated.

Finally, AGI’s Center for Space Standards & Innovation (CSSI) in Colorado Springs offers the Socrates and Socrates-GEO services. Socrates (http://celestrak.com/socrates/) is a service for satellite owner/operators that lists the top 10 pending potential satellite collisions each week. In early 2008, CSSI began offering Socrates-GEO, an enhanced version of the service that monitors satellites in geostationary (GEO) orbit. Socrates-GEO uses a variety of improved orbital data sources, most notably high-precision owner/operator orbit ephemerides, to provide improved conjunction monitoring for participants. Using this information can significantly reduce the number of false alarms, particularly with conjunctions between two operational satellites.

The relatively new Socrates-GEO service is used by organizations including Intelsat, Inmarsat, EchoStar, SES (Astra, New Skies and Americom), NOAA and Star One. The U.K.’s Ministry of Defense, U.S. Air Force Space Command, NRO and many other U.S. and globally based companies use the products for space situational awareness. For example, Hall said that during the highly publicized U.S Navy intercept of a failed NRO satellite in March 2008, Lockheed Martin used AGI’s desktop software to ingest Pocket Stars SP ephemeris of satellite (VCM), plot ship location, analyze radar search sectors and model missile engagement scenarios to support a legacy simulator in determining the optimum time for intercept. Display engagement in 3-D was used to illustrate and model this complex event, and Lockheed and the U.S. Navy successfully used an SM-3 missile to engage and intercept the target satellite in a way to minimize resultant on-orbit debris.

At AGI’s August Users’ Conference, Agilex Technologies showed how it uses AGI’s STK software to identify satellite maneuvers and mistags in the satellite catalog database. By using STK to propagate forward a given satellite’s twoline element (TLE) data to the time of the next TLE update, the prior (predicted) and updated positions may be simply differenced. The resulting difference measurements give observations regarding estimating the expected TLE positional error uncertainty. A byproduct of this analysis is that satellite maneuvers exceeding the error uncertainty result in TLE difference spikes. These spikes may be simply thresholded to detect maneuvers, or with a much larger threshold, catalog mistag errors: key technical capabilities for space protection. AGI’s Conjunction Analysis Workshop at the 2009 conference also provided detail on how their products and services can support SSA.

While existing AGI technology provides significant capability in the SSA arena, several changes are under way as they evolve their products. “First, we will soon be including a space environment modeling tool, developed by our business partner Atmospheric Environmental Research [www.aer.com], for modeling and analyzing several key items regarding the space environment, including things like the South Atlantic Anomaly, the radiation environment and magnetic field modeling,” said Hall. “Second, we are excited to be deploying a new electro-optical and infrared sensor modeling capability, developed by our business partner Space Dynamics Laboratory [www.spacedynamics.org]. This capability will allow users to layer true signalto- noise sensor modeling based upon detailed sensor properties on top of our time-based geometrical modeling.”

Last, AGI is making changes to its star modeling to include more star databases for users to choose from as well as several usability improvements when working with star databases. “This will enhance the ability of those performing sensor-based SSA analyses to more accurately and quickly model the overall environment,” Hall concluded. “Collectively, these enhancements will continue the practice of constantly evolving and improving our capabilities to support SSA analysis.”

SATID SYSTEM

The U.S. military has spent hundreds of billions of dollars over the last decade developing a net-centric force. While acting as a force multiplier to increase U.S. military capabilities, the move toward fielding a net-centric force has also created vulnerabilities that adversaries can exploit with relative ease to blind and cripple U.S. assets. A key enabler of the net-centric concept of operations is the use of satellite communications (SATCOM) networks to link systems deployed throughout the world.

These links, however, are vulnerable to jamming and interference by adversaries, John Friedman, senior project manager, and Ben Mathews, systems engineer at RT Logic, told MSMF. RT Logic is a wholly owned subsidiary of Integral Systems. By disrupting the SATCOM links that connect fielded forces with intelligence, surveillance, and reconnaissance, and command and control assets, their effectiveness is reduced significantly. In order to defeat this threat, systems are required that can effectively detect, characterize and locate sources of intentional jamming as well as unintentional interference.

“The satID signal geolocation system is an accurate, fast, all-in-one solution for quickly and accurately detecting, characterizing and geolocating ground-tosatellite transmission sources,” said Friedman and Mathews. “Powerful, flexible, and modular, satID uniquely blends complex science and algorithms with sophisticated hardware, digital signal processing, and a user-friendly wizard interface, resulting in an easyto- use package for locating and identifying sources of intentional jamming, accidental interference, equipment failure, or operator error.”

Over the past 20 years, extensive research and development have been invested into the creation and fielding of the satID system. Developers set out to produce a tool that was both easy to use and extremely powerful, establishing and honing techniques to locate the origin of unauthorized signals transmitted over satellites. Built upon traditional time difference of arrival and frequency difference of arrival methods, satID has evolved to include additional proprietary and patented techniques that extend performance and capabilities far beyond those accessible via traditional techniques.

To date, systems have been sold worldwide to a broad range of customers, validating RT Logic’s solution across a variety of industries and applications. “Our customers range from global and regional commercial satellite operators to national regulatory bodies and from government and military organizations to prime contractors within the domestic and foreign defense markets,” said Friedman and Mathews. “With our long, established history of continuous product development and innovation, and our reputation for providing world-class technical support, satID customers have confidence that investments made in satID products and services will provide formidable and sustained advantage over other potential solutions.”

The satID system continues to evolve. Key hardware and software innovations are leading to higher accuracy, faster and easier geolocation, even under the most challenging signal conditions. These developments include advancements in signal acquisition and processing capabilities, strengthened signal switching and frequency conversion functions, and improved scenario creation and visualization. “Current efforts improve satID’s modularity at the hardware and software levels, making it more scalable to evolving customer needs while decreasing total cost of ownership,” concluded Friedman and Mathews. “Enhanced interoperability with other Integral Systems and third-party products will add substantial new capabilities through strategic product blends.” ♦

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