The traditional approach to launch safety, based on a comprehensive system review to verify the flightworthiness, has provided assurance and success for many launches. Today, recognizing the rise of new commercial entrants, the individual needs for launch safety have become much more nuanced and complex to support new, innovative solutions to launch safety. This calls for a spectrum of approaches to launch safety based on individual operators’ needs and limitations.
The process used to independently determine launch system flight readiness is a capability unique to The Aerospace Corporation. This capability, which is available through the Space Safety Institute, has been employed for more than 50 years but is also adapting to today’s agile environment to provide flexible, cost-effective launch safety assurance to the customer.
The preferred approach for disposing of launch stages and spacecraft after end of mission is to have them reenter the atmosphere, where they will “burn up” and pose no additional hazard. Unfortunately, evidence shows that not all of a space vehicle will be destroyed, and some fragments will survive, becoming hazards to people on the ground and possibly even people in aircraft.
After the 1997 survival of a 500 lb. fragment from a reentering rocket stage, Aerospace formed its Center for Orbital and Reentry Debris Studies (CORDS) to conduct research on reentry breakup and the hazards these events pose. Through CORDS, Aerospace conducts metallurgical analyses of several fragments of reentered debris and has developed its Reentry Breakup Recorder to collect in situ data during the reentry and breakup of a vehicle. The Space Safety Institute incorporates results of these analyses and experiments, which are regularly published and presented at international conferences.
Aerospace’s launch verification process is traceable to the Mercury-Atlas and Gemini-Titan programs of the 1960s. The process, shown below, is rigorous, tailorable, and highly structured. System design validation (nonrecurring, or NR) validates that the system design; qualification; and engineering, manufacturing, and assembly processes satisfy system requirements. Launch readiness verification (recurring, or R) verifies that manufacturing, assembly, integration, preflight operations, and mission-specific design do not induce errors affecting the mission.
Aerospace is also a leader in developing reentry hazard assessment tools that reflect findings of its independent research in this area. The Space Safety Institute uses these tools to:
- Provide independent assessments of contractor survivability and hazard predictions
- Develop estimates of hazards associated with the reentry of government and commercial satellites
- Assess the risk to aircraft posed by small debris that might survive reentry from satellites from large constellations
- Provide independent verification of launch vehicle and spacecraft compliance with existing reentry hazard minimization policies
- Inform discussions on risks and requirements for disposal of satellites from large constellations
Standards and Best Practices
The Space Safety Institute participates in the development of international standards that capture best practices for minimizing hazards associated with reentry disposal of space hardware.
Aerospace, founded in 1960 to provide technical oversight and guidance for launch and space systems supporting U.S. national defense, has been and remains an active participant in their evolution. This long-term involvement and responsibility have created a deep corporate memory in virtually all things related to space.
For example, intimate knowledge of the components of launch and space systems—and of failures and anomalies associated with these systems—is key to improving reliability. Aerospace’s proprietary Acquisition Support and Systems Engineering Tool (ASSET) database, established in 1962, maintains detailed descriptions and findings related to off-nominal incidents associated with virtually all launch and space vehicles. ASSET includes anomaly data down to the component level—a level of detail that has supported overall reliability improvements and has been captured in standards and best practices that have lowered launch and space vehicle failure rates for decades.
Space debris mitigation policies specify that spacecraft and launch vehicle stages being disposed of into the atmosphere must limit the hazards to people on the ground that might result from impacts of debris that survives reentry. Aerospace has participated in the development of international standards that specify how the hazard on the ground should be estimated.
Estimating the hazard on the ground requires accurate estimates of the components that will survive a reentry and where they will land. Aerospace’s Reentry Breakup Recorder has provided in situ data on reentry breakup of space vehicles that has refined hazard prediction models worldwide.
Research and Development
Aerospace has maintained research activities that support reentry hazard estimation since the 1970s. The Space Safety Institute collaborates with CORDS to continue to research this area. Results are published and are used by reentry breakup researchers worldwide. Research activities includes:
- Examining hardware surviving reentry of commercial systems, with results returned to the owner
- Maintaining a database of reentered objects that have been returned for analysis
- Collecting and processing data collected by Aerospace’s REBR during the actual reentry and breakup of space vehicles
Infrastructure, Tools, and Data
For launch, verification of design and qualification of the launch system take place in every technical discipline. Each discipline utilizes state-of-the art tools to carry out these verifications. Similarly, mission planning verification undertakes mission-unique analyses to assess capabilities and margins.
LAUNCH VERIFICATION AND VALIDATION
- Structural design
- Thermostructures design
- Propulsion design
- Fluid mechanics design
- Mechanical design
- Avionics design
- Guidance, navigation, and control design
- Ground systems design
- Liftoff transients analysis
- Aerodynamic analysis
- Thermal analysis
- Structural dynamics analysis
MISSION PLANNING VERIFICATION AND VALIDATION
- Structural loads and dynamics
- Structural margins
- Guidance, navigation, and control
- Trajectory, targeting, and performance
- Launch day placards for ground winds and winds aloft
- Flight safety
- Telemetry and range coverage
- Electromagnetic interference
- Collision avoidance
Aerospace maintains reentry hazard estimation tools that are informed by metallurgical examinations and assessments of recovered debris conducted in our laboratories, as well as data on reentry breakup collected by the Reentry Breakup Recorder.
Policy and Strategy
There are significant safety and operational concerns related to launching into and reentry from space. Traditional methods of launch and planned reentry safety—including flight plan approvals, closures of air and marine spaces, and assurance of destruction systems—will be challenged with increasing operational tempos and responsiveness. The Space Safety Institute can assist in addressing alternatives that allow the integration of launch traffic into air and marine traffic as vehicles become more reliable and operations become more routine. The nature of launch and planned reentry are international events that cross oceans and international borders and will benefit from international standards to ensure public safety. The Space Safety Institute can also address issues associated with environmental impacts of launch and reentry.
- Paper: Slash the Trash: Incentivizing Deorbit (Apr 2020)
- Paper: Airspace Integration in an Era of Growing Launch Operations (Oct 2020)
- Paper: Large Constellation Disposal Hazards (Jan 2020)