On-Orbit Debris Mitigation Methods for Upper Stages

1. On-Orbit Debris Mitigation Methods for Upper Stages COMSTAC: Space Transportation Operations Working Group and Risk Management Working Group October 28, 2009

2. Agenda • Introduction - Jim Van Laak • Presentation on the disposal of launch vehicle orbital stages - Nicholas Johnson • Review of FAA current regulations and history - Elizabeth Gonzales • U.S. Government Space Debris Mitigation Standard Practices • Questions for COMSTAC

3. The Disposal of Launch Vehicle Orbital StagesNicholas L. JohnsonChief Scientist for Orbital DebrisNASA-JSC

4. History of FAA Orbital Debris Mitigation Regulations • 1988 FAA publishes first regulations for licensing; no regulations on orbital debris mitigations • 1999 FAA revised the licensing regulations and added requirements for safety at the end of launch for upper stages • No unplanned contact • No explosions caused by the conversion of energy sources • The commercial, defense, and scientific space community voiced a concern for the growing space safety due to the increasing number of objects placed in orbit. • The FAA elected to adopt only selected debris mitigation practices that were of almost universal applicability.

5. FAA Regulations – End of Launch ELV • § 417.129: A launch operator must ensure for any proposed launch that for all launch vehicle stages or components that reach Earth orbit— • There is no unplanned physical contact between the vehicle or any of its components and the payload after payload separation; • Debris generation does not result from the conversion of energy sources into energy that fragments the vehicle or its components. Energy sources include chemical, pressure, and kinetic energy; and • Stored energy is removed by depleting residual fuel and leaving all fuel line valves open, venting any pressurized system, leaving all batteries in a permanent discharge state, and removing any remaining source of stored energy.

6. FAA Regulation – End of Launch RLV • § 431.43 (c)(3) For an RLV mission – • There will be no unplanned physical contact between the vehicle or its components and payload after payload separation and debris generation will not result from conversion of energy sources into energy that fragments the vehicle or its payload. Energy sources include, but are not limited to, chemical, pneumatic, and kinetic energy;

7. U.S. Government Orbital Debris Mitigation Standard Practices

8. U.S. Government Orbital Debris Mitigation Standard Practice 1 • CONTROL OF DEBRIS RELEASED DURING NORMAL OPERATIONS • Programs and projects will assess and limit the amount of debris released in a planned manner during normal operations. • MITIGATION STANDARD PRACTICES • 1-1. In all operational orbit regimes: Spacecraft and upper stages should be designed to eliminate or minimize debris released during normal operations.

9. U.S. Government Orbital Debris Mitigation Standard Practice 2 • MINIMIZING DEBRIS GENERATED BY ACCIDENTAL EXPLOSIONS • Programs and projects will assess and limit the probability of accidental explosion during and after completion of mission operations. • MITIGATION STANDARD PRACTICES • 2-1. Limiting the risk to other space systems from accidental explosions during mission operations • 2-2. Limiting the risk to other space systems from accidental explosions after completion of mission operations

10. U.S. Government Orbital Debris Mitigation Standard Practice 3 • SELECTION OF SAFE FLIGHT PROFILE AND OPERATIONAL CONFIGURATION • Programs and projects will assess and limit the probability of operating space systems becoming a source of debris by collisions with man-made objects or meteoroids. • MITIGATION STANDARD PRACTICES • 3-1. Collision with large objects during orbital lifetime

11. U.S. Government Orbital Debris Mitigation Standard Practice 4 • POSTMISSION DISPOSAL OF SPACE STRUCTURES • Programs and projects will plan for, consistent with mission requirements, cost effective disposal procedures for launch vehicle components, upper stages, spacecraft, and other payloads at the end of mission life to minimize impact on future space operations. • MITIGATION STANDARD PRACTICES • 4-1. Disposal for final mission orbits

12. U.S. Government Orbital Debris Mitigation Standard Practice 4 • Atmospheric reentry option • Leave the structure in an orbit in which, using conservative projections for solar activity, atmospheric drag will limit the lifetime to no longer than 25 years after completion of mission. • If a space structure is to be disposed of by reentry into the Earth’s atmosphere, the risk of human casualty will be less than 1 in 10,000.

13. U.S. Government Orbital Debris Mitigation Standard Practice 4 • Maneuvering to a storage orbit: At end of life the structure may be relocated to one of the following storage regimes: • Between LEO and MEO: Perigee altitude above 2000 km and apogee altitude below 19,700 km (500 km below semi-synchronous altitude • Between MEO and GEO: Perigee altitude above 20,700 km and apogee altitude below 35,300 km (approximately 500 km above semi-synchronous altitude and 500 km below synchronous altitude.) • Above GEO: Perigee altitude above 36,100 km (approximately 300 km above synchronous altitude) • Heliocentric, Earth-escape: Maneuver to remove the structure from Earth orbit, into a heliocentric orbit.

14. U.S. Government Orbital Debris Mitigation Standard Practice 4 • Direct retrieval • Retrieve the structure and remove it from orbit as soon as practical after completion of mission.

15. QUESTIONS

16. Question 1 • What are the impacts to industry of complying with one of the U.S. Government Orbital Debris Mitigation Standard Practice for post-mission disposal (atmospheric reentry, storage orbit, or direct retrieval)? • List the companies’ required change(s) for complying with a post-mission disposal plan for the upper stage. If no change is required please make this statement. • List the assumptions and costs to the company associated with each required change.

17. Question 2 • What is the total cost to maneuver an upper stage after mission completion to an orbit that limits the lifetime to 25 years? • The total cost can be classified per payload weight or per launch vehicle class. • List the assumptions that went into this cost estimate.

18. Question 3 • What is the cost to move an upper stage after mission completion to an orbit that meets the storage orbit options? • The total cost can be classified per payload weight or per launch vehicle class. • List the assumptions that went into this cost estimate.

19. Question 4 • What is the cost to perform a controlled deorbit of the upper stage after mission completion and before the stage becomes inoperable? • The total cost can be classified per payload weight or per launch vehicle. • List the assumptions that went into this cost estimate.

20. Question 5 • What is the impact to the commercial space industry of complying with the U.S. Government Orbital Debris Mitigation Standard Practices of eliminating or minimizing each instance of planned release of debris larger than 5 mm in any dimension that remains on orbit for more than 25 years? • List the companies’ required change(s) to implement the process of eliminating or minimizing the planned release of debris. • List the assumptions and costs to the company associated with the change(s) required for implementation.