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Commercial Space Vehicle Tracking Using 1090 MHz ADS-b

Description:

Commercial space vehicles licensed by the FAA include launch vehicles, re-entry vehicles and manned high altitude balloons.  Operations of commercial space vehicles will become increasingly frequent and then routine in various regions of the US.  The primary objective of this research is to ensure no degradation to both the safety and efficiency of the National Airspace (NAS) for other NAS users such as commercial general and military aviation occurs as commercial space vehicles become routine.  The proposed research will build on existing Automatic Dependent Surveillance-Broadcast (ADS-B) to perform surveillance of commercial space vehicles as they transition through the NAS either on the ascent or descent phases of flight by building on existing, operational, flight- proven 1090MHz Automatic Dependent Surveillance-Broadcast (ADS-B) technology.  ADS-B is germane to any nature of flight operations (a characteristic attributed to GPS based technologies); this service could be used to surveil commercial space operations, and provide much needed information to ATM services that are responsible for the associated operational environments and provide them situational awareness of these vehicles above the NAS.  Accordingly, while ADS-B is potentially a favorable candidate for surveillance of commercial space operations, extensive research is required to determine the necessary operational, functional and physical system characteristics for development of an adequate spacecraft surveillance platform(s).

 

ADS-B “Out” equipment transmits position and velocity and other information from a given aircraft to the operating network of ~650 ADS-B ground based receivers for use by Air Traffic Control personnel.   It operates at frequencies of 978MHz and 1090MHz.  However current ADS-B “Out” equipment for commercial and general aviation is designed to operate below 60,000 feet at subsonic velocities and accelerations below 4Gs, making it of limited value to commercial space vehicles.  While a prototype 978 MHz ADS-B Out specifically designed for commercial space vehicles has been flown on high altitude balloons and various rocket powered vehicles (including a commercial launch vehicle), an analogous1090 MHz ADS-B Out prototype has not been designed, let alone developed.  Aside from its transmission frequency, 1090MHz equipment has a different message structure and other characteristics from 978MHz.   Equipment in both frequencies offer unique benefits to space transportation operations in the NAS and are needed for test flights to properly evaluate them.  Additionally, 978MHz is primarily used in the US whereas 1090 MHz is used internationally so that US-built commercial space vehicles equipped with a functioning 1090 MHz ADS-B Out could more easily operate in these countries.  Finally the capability for receipt of ADS-B messages from a commercial space vehicle beyond line of sight of FAA receivers (over broad ocean areas, mountainous areas, deep valleys) is an enabler for continuous seamless tracking of these vehicles. This capability is achievable using existing  communications satellite capabilities at low cost but has not been demonstrated with commercial space vehicles and is a necessary research shortfall to be addressed in this effort

 

Expected Phase I Outcomes:

 

  • Perform a trade study exploring 1) upgrading existing commercial 1090 MHz ADS-B Outfor use on commercial launch vehicles , re-entry vehicles and manned high altitude balloons or 2)“clean sheet design” and deliver study findings.  Based on this trade study select a path forward and  provide 1) preliminary design information for a 1090 MHz ADS-B Out prototype and one (1) functioning  “bread board” level maturity prototype.  During Phase I, the delivered  prototype will be used  for independent function/ performance testing with the FAA GPS altitude/velocity simulator as well as high altitude balloon flights (funded or arranged by FAA) to collect and analyze trajectory data.  Trajectory data will be used to evaluate prototype performance and to develop and anchor modeling and simulation exercises.
  • In parallel to task described above perform a trade study on optimal means of transmitting ADS-B messages from the payload using an existing communication satellite message format/technology when it is not line of sight of FAA receiving equipment.  Study will explore 1) upgrading existing commercial satellite communication equipment that has minimal latency capability and low power, volume and weight for use on commercial launch vehicles, re-entry vehicles and manned high altitude balloons or 2) a “clean sheet design” utilizing readily available COTS technology for this application and deliver study findings.  Based on this trade study select a path forward and  provide 1) preliminary design information for a commercial satellite communication transmitter to support ADS-B payload described above and one (1) functioning  “bread board” level maturity prototype capable of receiving data (i.e.ADS-B messages) from  the ADS-B equipment described above and transmitting it for tracking purposes.  During Phase I,  the delivered  prototype will be used  for independent function/ performance testing to receive and transmit data as well as high altitude balloon flights and potentially flights on rocket powered vehicles

Expected Phase II Outcomes:

 

  • Design and develop commercial space flight surveillance test bed, as is described within the formulated study plan within phase 1 of this research endeavor. Test bed should include hardware and software development capabilities, as well as full-fidelity simulation tools.
  • Deliver TBD (up to a total of 10) 1090MHz ADS-B prototypes for ground testing in the test bed described above and on commercial  space transportation platforms (tro be arranged by FAA)
  • Initial delivery of TBD (up to 5) early prototypes based on lessons learned from and design of bread board model delivered in phase I for ground testing balloon and suborbital testing TBD months after award of Phase II
  • Follow on delivery of TBD (up to 5) advanced  prototypes based on lessons learned from and design of bread board model delivered in phase I for ground testing balloon and suborbital testing TBD (greater than 6 months after award)
  • Perform viability and reliability testing to establish whether phase 1 outcomes produce a practical solution for surveillance of commercial space flights within the National Airspace System (NAS). Viability testing will examine if the provided surveillance data for a commercial space flight satisfies the information requirements needed for air traffic management and airspace accessibility. Reliability testing will seek to identify the integrity of that surveillance information by determining the level of maintained surveillance accuracy and the frequency of “drop-outs” or degradation in signal. From these tests, a preliminary feasibility assessment can be made, and if deemed viable and reliable, the associated philosophy of use for the prototype ADS-B transceiver can then begin formal development (to be eventually captured within a Concept of Operations or a Concept of Use).
  • Preform a limited set of operational assessment studies, in which the impacts to safety and efficiency across different environments are identified and examined. The goal of these studies will be to establish an initial set of findings that identify correlative relationships between a commercial space flight transiting an airspace sector and the general effects imposed upon that airspace. To accomplish such, studies could vary traffic levels, traffic configuration, airspace size, and the direction of transit for the commercial spacecraft (i.e. inbound or outbound). Overall, the outcome of this research will begin to identify challenges to full integration of commercial space flights within the NAS.
  • Publish a final report capturing the findings of the above outlined activities which, in summary, will provide an initial overall assessment of the ADS-B prototype, including its functionality, operational viability, operational reliability, and operational applicability and a path forward to commercial use

 

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