U.S. Department of Transportation Advisory Federal Aviation Administration Circular Subject: Tracking for Launch and Reentry Safety Date: 09/29/2022 AC No: 450.167-1 Analysis Initiated By: AST-1
This advisory circular (AC) provides guidance for an operator to measure and record in real time the position and velocity of a launch or reentry vehicle during flight, in accordance with Title 14 of the Code of Federal Regulations (14 CFR) § 450.167, Tracking. Under § 450.167(a), the system used to track the vehicle must provide data to predict the expected impact locations of all stages and components, and obtain vehicle performance data in real time for comparison to preflight performance predictions. In accordance with § 450.167(b), an applicant must identify and describe each method or system used to meet these tracking requirements in their license application.
The Federal Aviation Administration (FAA) considers this AC an accepted means of compliance for complying with the regulatory requirements of § 450.167. It presents one, but not the only, acceptable means of compliance with the associated regulatory requirements. This guidance is not legally binding in its own right and will not be relied upon by the FAA as a separate basis for affirmative enforcement action or other administrative penalty. Conformity with the guidance is voluntary only and nonconformity will not affect rights and obligations under existing statues and regulations.
If you have suggestions for improving this AC, you may use the Advisory Circular Feedback form at the end of this AC.
Kelvin Coleman Associate Administrator FAA, Office of Commercial Space Transportation
Contents Paragraph Page ii
1 Purpose1
2 Applicability1
3 Applicable Regulations and Related Documents2
4 Definitions4
5 Acronyms5
6 Overview6
6.1 Importance of Tracking Data6
6.1.1 Tracking Data used for Post-flight Reporting6
6.1.2 Tracking Data during a Mishap6
6.1.3 Tracking Data for Flight Abort6
7 Tracking Measurement8
7.1 General Guidance8
7.1.1 Applicability and Availability of each Tracking Method8
7.1.2 Tracking Methodologies8
7.1.3 Launch Sites8
7.2 Applicability of Various Tracking Methods9
7.2.1 Launch Vehicle Flights9
7.2.2 Reentry Vehicle Flights9
7.2.3 Stage or Component Impact Locations9
7.3 Availability of Tracking Methods10
7.3.1 Telemetered Inertial Guidance10
7.3.2 Radar Beacon Tracking10
7.3.3 Radar Skin Tracking11
7.3.4 Tracking and Data Relay Satellite System11
7.3.5 GPS Metric Tracking via S-band Telemetry Downlink12
7.3.6 Optical Tracking12
8 Tracking and Recording Data13
8.1 Data to be Tracked in Real Time13
8.2 Methods of Recording13
8.3 Data Fidelity14
Contents (continued) Paragraph Page iii
8.3.1 Sample Rate14
8.3.2 System Delay Time14
8.3.3 Accuracy15
8.3.4 Reliability16
8.3.5 Quality/Confidence Indicators16
8.3.6 Independence16
9 Application Requirements17
9.1 Methods17
9.2 Systems17
9.3 Range Commander’s Council (RCC) 32417
1 1 PURPOSE.
1.1 This AC provides guidance and an acceptable means of complying with the requirement to track the flight of a launch or reentry vehicle under 14 CFR § 450.167 using onboard hardware, launch site services, or other means. In addition, this AC provides an understanding of the current technologies and parameters used for implementing tracking services, which operators may use to meet the requirements of § 450.167. The real-time tracking guidance in this AC can also be used to meet tracking requirements when using a flight safety system for any phase of flight where an operator must implement flight abort in accordance with § 450.108.
1.2 Level of Imperatives.
This AC presents one, but not the only, acceptable means of compliance with the associated regulatory requirements. The FAA will consider other means of compliance that an applicant may elect to present. In addition, an operator may tailor the provisions of this AC to meet its unique needs, provided the changes are accepted as a means of compliance by the FAA. Throughout this document, the word “must” characterizes statements that directly follow from regulatory text and therefore reflect regulatory mandates. The word “should” describes a requirement if electing to use this means of compliance; variation from these requirements is possible but must satisfy the regulation to constitute an alternative means of compliance. The word “may” describes variations or alternatives allowed within the accepted means of compliance set forth in this AC.
2 APPLICABILITY.
2.1 The guidance in this AC is for launch and reentry vehicle applicants and operators required to comply with 14 CFR part 450. The guidance in this AC is for those seeking a launch or reentry vehicle operator license, and licensed operators seeking to renew or modify existing vehicle operator licenses.
2.2 The material in this AC is advisory in nature and does not constitute a regulation. This guidance is not legally binding in its own right and the FAA will not rely upon this guidance as a separate basis for affirmative enforcement action or other administrative penalty. Conformity with this guidance document (as distinct from existing statutes and regulations) is voluntary only, and nonconformity will not affect rights and obligations under existing statutes and regulations.
2.3 The material in this AC does not change or create any additional regulatory requirements, nor does it authorize changes to, or deviations from, existing regulatory requirements.
2 3 APPLICABLE REGULATIONS AND RELATED DOCUMENTS.
3.1 Related United States Code (U.S.C.) Statute.
• 51 U.S.C. Subtitle V, Chapter 509.
3.2 Related FAA Commercial Space Transportation Regulations.
The following 14 CFR regulations must be accounted for when showing compliance with § 450.167. The full text of these regulations can be downloaded from the U.S.
Government Printing Office e-CFR. A paper copy can be ordered from the Government Printing Office, Superintendent of Documents, Attn: New Orders, P.O. Box 371954, Pittsburgh, PA, 15250-7954.
• Section 401.7, Definitions.
• Section 450.35, Means of compliance.
• Section 450.108, Flight abort.
• Section 450.145, Highly reliable flight safety system.
• Section 450.167, Tracking.
3.3 Related FAA Advisory Circulars.
FAA Advisory Circulars are available through the FAA website, http://www.faa.gov.
• AC 450.35-1, Means of Compliance, when published.
3.4 Related Industry and Government Documents.
• Air Force Space Command Instruction (AFSPCI) 91-701, Launch and Range Safety Program Policy and Requirements, dated February 1, 2019. https://static.epublishing.af.mil/production/1/afspc/publication/afspci91-701/afspci91-701.pdf.
• Air Force Space Command Manual (AFSPCMAN) 91-710, Volume 2, Range User Launch Safety Requirements Manual, Volume 2, Flight Safety Requirements, dated July 13, 2017. https://static.e- -publishing.af.mil/production/1/afspc/publication/afspcman91-710v2/afspcman91- 710v2.pdf.
• Alaska Aerospace Corporation, Pacific Spaceport Complex Alaska Commercial Launch Site Safety Manual, dated May 2018.
http://www.akaerospace.com/sites/default/files/download/Commercial%20Launch% 20Site%20Safety%20Manual.pdf.
• Goddard Space Flight Center, Space Network User’s Guide (SNUG), Revision 10, dated August 3, 2012. http://everyspec.com/NASA/NASA-GSFC/GSFC-Code- Series/450-SNUG_REV-10_50333/.
• National Aeronautics and Space Administration (NASA) Technical Standard, Goddard Flight Facility Range Safety Manual, GSFC-STD-8009, dated June 05, 2019. https://standards.nasa.gov/standard/gsfc/gsfc-std-8009.
• Powell, O., Dickens, Devin, and Lyle, Jack. 2017. Space Launch Automation and Integration: A Common Architecture for Mission Assurance, Safety, and Launch Operations. 33rd Space Symposium, Technical Track, Colorado Springs, CO, dated April 3, 2017. http://2019.spacesymposium.org/wpcontent/uploads/2017/10/Powell_Rusty_Space_Launch_Automation_and_Integratio
n.pdf
• Range Commanders Council (RCC), Inter-Range Instrumentation Group (IRIG) Standard 106-19, Telemetry Standards, dated July 2019.
http://www.irig106.org/docs/106-19/106-19_Telemetry_Standards.pdf
• RCC Standard 262-14, C (G) – Band and X (I) Non-coherent Radar Transponder Performance Specification Standard, dated June 2014.http://www.irig106.org/docs/rcc/262- 14_Radar_Transponder_Specification.pdf
• RCC Standard 319-14, Flight Termination Systems Commonality Standard, dated September, 2014. ADA620923.pdf (dtic.mil)
• RCC Standard 321-10, Common Risk Criteria Standards for National Test Ranges, dated December 2010. https://apps.dtic.mil/dtic/tr/fulltext/u2/a639830.pdf
• RCC Standard 324-11, Global Positioning and Inertial Measurements Safety Tracking Systems Commonality Standard, dated February 2011.
https://www.wsmr.army.mil/RCCsite/Documents/324- 11_GPS_Inertial_Msmts_Safety_Tracking_Sys/324- 11_GPS_Inertial_Msmts_Safety_Tracking_Sys.pdf
• U.S. Air Force, Eastern Range User Handbook, 45th Space Wing, dated January 2019. https://www.patrick.af.mil/About-Us/New-Customer-Information/
• U.S. Air Force, Western Range User Handbook, 30th Space Wing Instruction 13-203, dated August 26, 2009. https://static.epublishing.af.mil/production/1/30sw/publication/30swi13-203/30swi13-203.pdf
4 4 DEFINITIONS.
For this AC, the definitions from § 401.7 and this list apply:
4.1 State Vector A set, at a minimum, is comprised of three-component positions and three-component velocities with a point in time along a vehicle’s trajectory. A state vector may also include vehicle mass, thrust, orientation, angular velocity, and other parameters.
4.2 Verified Tracking Source A tracking source is considered to be verified when it produces the same solution as another independent tracking source. A verified tracking source must be re-verified after a shock event such as stage separation.
5 5 ACRONYMS.
AC – Advisory Circular AFSPCI – Air Force Space Command Instruction AFSPCMAN – Air Force Space Command Manual AFSS – Autonomous Flight Safety System AST – Office of Commercial Space CFR – Code of Federal Regulations DOP – Dilution of Precision ELV – Expendable Launch Vehicle FAA – Federal Aviation Administration FSS – Flight Safety System GPS – Global Positioning System GRGT – Guam Remote Ground Terminal GSFC – Goddard Space Flight Center IIP – Instantaneous Impact Point IMU – Inertial Measurement Unit IRIG – Inter-Range Instrumentation Group MOCC – Mission Operation Control Center NAS – National Airspace System NASA – National Aeronautics and Space Administration NIMO – Network Integration Management Office RCC – Range Commander’s Council RLV – Reusable Launch Vehicle RSS – Root of the sum of the squares RTS – Range Tracking System RV – Reentry Vehicle TDRSS – Tracking and Data Relay Satellite System TMIG – Telemetered Inertial Guidance U.S.C. – United States Code WSC –White Sands Complex
6 6 OVERVIEW.
In accordance with § 450.167(a), during the flight of a launch or reentry vehicle, an operator must measure and record in real-time (i.e. track) the position and velocity of the vehicle. The system used to track the vehicle must provide data to predict the expected impact locations of all stages and components and to obtain vehicle performance data for comparison with the pre-flight performance predictions.
6.1 Importance of Tracking Data.
Tracking data enables operators to compare post-flight data under § 450.103(d), respond to mishaps in accordance with § 450.173, and satisfy the flight abort requirements of § 450.108(f)(1) when flight abort is used as the hazard control strategy under § 450.107.
6.1.1 Tracking Data used for Post-flight Reporting.
An operator must employ a process for evaluating post-flight data in accordance with § 450.103(d). Recorded tracking data is used to compare predicted performance to actual performance. The tracking data is also used to ensure the flight was conducted in accordance with mission analyses and enables operators to identify and resolve any issues affecting public safety before the next flight occurs. Under § 450.215(b)(4), the operator must provide the actual trajectory flown if requested by the FAA.
6.1.2 Tracking Data during a Mishap.
Mishaps present a risk to public safety. Tracking data sufficient to predict the location of any vehicle or component impacts following an off-nominal situation can enable an appropriate response, such as knowing where to apply fire suppression resources, or where to evacuate the public to protect against predicted toxic plumes. Tracking data obtained pursuant to § 450.167(a) would enable operators to effectively implement their mishap response plan in accordance with § 450.173. Should a mishap occur midflight, tracking data should be recorded at least as long as necessary to establish expected impact locations of all stages and components, or until vehicle break-up occurs.
6.1.3 Tracking Data for Flight Abort.
The FAA requires that all part 450 licensees perform vehicle tracking in accordance with § 450.167, irrespective of the hazard control strategy selected under § 450.107.
The FAA notes, however, that for phases of flight that use flight abort as a hazard control strategy, real-time position and velocity of the vehicle are used to evaluate flight abort rules under § 450.108. In accordance with § 450.108(f)(2)(i), the flight safety system must abort flight when valid real-time data indicates that the vehicle has violated any flight safety limit. As discussed in paragraph 8 below, the FAA requires tracking data to be as close to real time as practicable, and pursuant to § 450.108(d)(4), operators must account for any time delay in their flight safety limits, including uncertainties between the violation of a flight abort rule and the time when the flight safety system is expected to activate. Therefore, real-time data is necessary to meet the flight safety limit objectives of § 450.108(c). For guidance on flight abort rules see AC 450.108 Flight Abort Rule Development.
6.1.3.1 The flight abort rules established in accordance with § 450.108(f)(2)(iii) govern the conduct of the launch or reentry if tracking data is invalid and further flight has the potential to violate a flight safety limit. In the event valid data is lost, an operator must use flight safety limits to calculate when flight abort rules should activate the flight safety system, which could include destruction of the vehicle amongst other actions, in accordance with § 450.108(d)(3). If at any point during the mission flight abort is required, the lack of valid tracking data will trigger the data loss abort rule.
6.1.3.2 Data loss flight time, also known as green numbers on the Eastern Range, is the time during which the launch vehicle moves from normal flight to activation of the flight abort system to ensure the safety of a protected area. See AC 450.108-1, Flight Abort Rule Development for more information on loss of data used to evaluate flight abort rules, including acceptable durations of data loss.
6.1.3.3 Scenario: An operator is flying with two tracking sources. Both of the tracking sources are providing the same solution therefore both sources are validated. If one tracking source is lost, the remaining tracking source is still considered to have valid data. A stage separation event causes a shock. At that point, the single tracking source becomes invalid and must be re-validated by a new source. If it is not validated, the operator would need to implement an approach (e.g. data loss flight times) to account for the loss of valid data in order to evaluate the flight abort rules in accordance with § 450.108(d)(3).
8 7 TRACKING MEASUREMENT.
7.1 General Guidance.
7.1.1 Applicability and Availability of each Tracking Method.
Each method of tracking has inherent advantages and disadvantages and cannot be universally applied at every phase of flight for every vehicle. Additionally, with the exception of local suborbital flights, geographical limitations of launch site support services, such as radar, necessitate the use of multiple services throughout a complete launch or reentry mission. This situation is due to inherent coverage limitations from telemetry and radar line of site. The intent of this paragraph of this AC is to provide an overview for the applicability and availability of each tracking method, as well as define the publicly available guidance documents that state common standards for each.
7.1.2 Tracking Methodologies.
Historically, a combination of methods such as skin- or beacon-track radar, optical tracking, Global Positioning System (GPS), transponders, or Inertial Measurement Units (IMU) validated with another IMU source, have been utilized to provide tracking throughout a mission. Other metric tracking systems methods proposed by an applicant would be evaluated for reliability, accuracy, and timeliness to provide an equivalent level of safety. These metrics are discussed in paragraph 8 of this AC for recommended fidelity and acceptability.
7.1.3 Launch Sites.
Each launch site has unique capabilities and systems that users need to be familiar with before deciding on which methodology will be utilized for tracking to meet the requirements of § 450.167. For launch from a Federal launch site, it is advisable to contact the associated safety office for a Range User Handbook when determining which system will be utilized for each mission. Services available at federal launch sites may not be available at commercial launch facilities. Design changes may be required if commercial tracking capabilities/systems are not available. Although each launch site maintains their own requirements for tracking systems, the requirements imposed at Federal launch sites are similar to the tracking requirements of part 417, and would meet the requirements of § 450.167. The following are requirements imposed by AFSPCMAN 91-710 at Federal launch sites, which may serve as guidelines for operators in developing a means to comply with § 450.167 when operating at non-Federal launch sites:
• Each tracking source and plan is designed so that no single order vehicle failure or ground based instrumentation failure mode could cause the loss of all tracking sources.
• Data from one tracking source will not influence another tracking source.
• At least two tracking sources should be operationally verified prior to launch.
• No less than two adequate and independent tracking sources from lift-off to orbital insertion (or past the final gate specified by flight analysis, analogous to end of flight abort conditions under § 450.108(e)) for an orbital flight, or to the end of powered flight for a suborbital launch.
• Any gap in coverage should not occur at the same time as any planned switching of command transmitters.1
7.2 Applicability of Various Tracking Methods.
7.2.1 Launch Vehicle Flights.
Each method of tracking listed in paragraph 7.3 of this AC may be utilized for any phase of launch so long as it can measure and record in real-time the position and velocity of the vehicle. At least one verified tracking source should be operational for all phases of launch for which tracking is required under § 450.167.
7.2.2 Reentry Vehicle Flights.
Each method of tracking listed in paragraph 7.3 of this AC can be used during and after the de-orbit burn up to and following the plasma phase of reentry, at which point the only tracking methods known to currently work are radar and/or optical tracking. Note that during reentry, radar and optical signatures of RVs are dependent upon several complex phenomena, which can complicate both pre-flight modeling tracking and post-flight analysis. As explained in paragraph 8 below, in order to satisfy § 450.167(b), an applicant should include the outcomes of any such modeling and analysis in their description of each tracking method or system used. Examples of these phenomena include vehicle shape and material construction, hard body surface temperature, trajectory conditions (altitude, velocity, and orientation), and details of the flow field surrounding and behind the vehicle. These flow field details include local distribution of temperature and chemical composition including plasma for part of the trajectory, and flow field turbulence. Position and velocity data recorded on board the Reentry Vehicle (RV) during plasma phase of reentry using IMU(s) must be provided to FAA post-flight to compare the actual and predicted nominal performance of the vehicle upon request, in accordance with § 450.215(b)(4).
7.2.3 Stage or Component Impact Locations.
In accordance with § 450.167(a), the system used to track the vehicle must provide data to predict the expected impact locations of all stages and components. Section 450.167 does not require operators to track individual components all the way down to the earth’s surface or body of water; the FAA requires only that operators track the vehicle in real time for the entirety of the flight such that they could identify expected impact locations of all stages and components. The FAA requires that operators employ a method of tracking sufficient to predict expected impact landings so that operators could properly respond in the event of an unplanned event or emergency. The use of
1 Air Force Space Command Manual (AFSPCMAN) 91-710, Volume 2, Range User Launch Safety Requirements Manual, Volume 2, Flight Safety Requirements, July 13, 2017.