You Are Not Alone: The Problem of Safe Operations in LEO Ted Muelhaupt 8 June 2016

The Problem Low Earth orbit is becoming more and more crowded Many new large constellations proposed Increased commercial launch rates Space tourism is on the horizon Existing operators are seeing an increase in collision alerts Space debris concerns interwoven with other traffic issues Military wants to divest itself of space traffic management and concentrate on the “protect and defend” mission Many asking “who will be the FAA for space?” New regulations and restrictions are likely. What form SHOULD they take? Some possible new constellations Operator Num sats Alt (km) Incl (deg) LeoSat 140 1800 90 Spire 100 651 97.9 OneWeb 648 1200 SpaceX 4000 1100 Skybox 28 576 97.8 Globalstar 40 1400 52 Iridium 72 780 86.4 Orbcomm 31 750 45

Consider a map of LEO space – just altitude

New constellations will intersect with existing residents Suborbital Flight LeoSat +140 OneWeb +648 SpaceX +4000 Skybox +28 Iridium +72 Orbcomm +31 New constellations Spire +100 Globalstar +40 Hubble NASA Science – A Train Human flight ISS NOAA weather Iridium Orbcomm Globalstar Existing residents

New constellations will intersect with existing residents LeoSat +140 Globalstar +40 Globalstar OneWeb +648 SpaceX +4000 NOAA weather Iridium +72 Iridium Orbcomm +31 Orbcomm NASA Science – A Train Spire +100 Skybox +28 Hubble Human flight ISS Suborbital Flight

Space debris is where the spacecraft live Hubble NASA Science – A Train ISS NOAA weather Iridium Orbcomm LeoSat +140 OneWeb +648 SpaceX +4000 Skybox +28 Globalstar +40 Iridium +72 Orbcomm +31 New constellations Existing residents Spire +100 Globalstar Human flight Suborbital Flight

Mass is more concentrated, different from numbers Hubble NASA Science – A Train ISS NOAA weather Iridium Orbcomm LeoSat +140 OneWeb +648 SpaceX +4000 Skybox +28 Globalstar +40 Iridium +72 Orbcomm +31 New constellations Existing residents Spire +100 Globalstar Human flight Suborbital Flight

New constellations can locally greatly exceed existing Hubble NASA Science – A Train ISS NOAA weather Iridium Orbcomm LeoSat +140 OneWeb +648 SpaceX +4000 Skybox +28 Globalstar +40 Iridium +72 Orbcomm +31 New constellations Existing residents Spire +100 Globalstar Human flight Suborbital Flight

New constellations can locally greatly exceed existing Hubble NASA Science – A Train ISS NOAA weather Iridium Orbcomm LeoSat +140 OneWeb +648 SpaceX +4000 Skybox +28 Globalstar +40 Iridium +72 Orbcomm +31 New constellations Existing residents Spire +100 Globalstar Human flight Suborbital Flight

Human Space Missions are Clustered Small group of inclinations, limits on altitude A zone of 300-450 km would encompass most human spaceflight

Number of Satellites in Bin Current Catalog Add inclination 100 101 102 103 104 Number of Satellites in Bin

Number of Satellites in Bin Current Catalog Spacecraft at same altitude but different inclinations can still intersect – depends on the right ascension 100 101 102 103 104 Number of Satellites in Bin

Future Catalog with New Space Constellations OneWeb SpaceX +Spire +Skybox 100 101 102 103 104 Number of Satellites in Bin

Future Catalog with New Space Constellations OneWeb SpaceX +Spire +Skybox ISS Manned missions 100 101 102 103 104 Number of Satellites in Bin

Disposal plans greatly affects the impact on new and old New operational constellations are proposed for relatively unpopulated areas. But… Constellations transiting up and down for replenishment and disposal cross other orbits Orbits at same altitude can cross any other orbit at that altitude A five-year lifetime implies that 20% of a constellation is replaced ~ each year Disposal plans will directly affect conjunction frequency OneWeb SpaceX +Spire +Skybox ISS 100 101 102 103 104 Number of Satellites in Bin

Large constellations will pose conjunction challenges New constellations can double the spatial density of objects over existing levels Collision alerts with existing operators could greatly increase Spatial density of new constellations at ISS altitude Note log scale

Large constellations pose challenges Disposal plans will make a large difference on the traffic at non-constellation altitudes Plot assumes a new large constellation is “spiraling down” old satellites Spatial density of new constellations compared to existing objects High density due to disposal

Even self-conjunctions are problematic for a Space Traffic Management agency Graphic shows a 4080 satellite Walker constellation at 90 deg One satellite passes through either pole every 1.6 sec White rings are 20 km bubbles around each object At any given moment, dozens of vehicles are within each others’ 20 km circle This (naïve) example has an average of ~27,000 20 km self-conjunctions each day

Aspects of Space Traffic Management Problem Space Traffic Management (STM) is multi-faceted: many things to consider Safety concerns On-orbit conjunction warning Transit of airspace en route to orbit or during disposal Space debris - environment preservation International obligations Space surveillance Legislative (authority for regulations) Legal (liability, ownership) Regulatory business planning US leadership Operator code(s) of conduct This area will evolve, perhaps quickly in some aspects.

Conjunction Predictions Some questions to consider Operators say timely and quality conjunction predictions (covariance) is of primary importance Probability of collision has a maximum related to the covariance Poor quality data may be un-actionable What is the role of owner/operator data? How can/will it be ingested? Should spacecraft file “flight plans” for maneuvers? Post-maneuver updates? How should we use commercial tracking data? Should new spacecraft carry tracking aids? Reflectors for radar or lasers? Transponders? What is the relationship of a civilian or commercial STM agency to the military? What is the flow of data? Can it task sensors? Are self-conjunctions within a constellation treated differently by an external STM agency?

Collision Avoidance Maneuvers Some questions to consider Who should have responsibility to maneuver, and in what situation – who has the right of way? Controlled vs. uncontrolled: ability to maneuver and avoid a collision Different from live vs inert / operational vs. non-operational Should there be “space lanes” with different rules? There are different rules for air and sea traffic in different situations; e.g. restricted airspace near airports Require active control or more rapid transit of “human zone”? Special considerations for sun-synchronous orbits? Should new spacecraft be required to be able to maneuver a minimum distance in a set amount of time? If so, then what about upper stages? How do we handle low-thrust (ion) maneuvering? TLEs and VCMs (orbit data formats) have very limited ability to account for object acceleration Low-thrust systems may be “untrackable” when under thrust

International Obligations and Liability Some questions to consider How will US treaty and international obligations affect US actions in STM? How should the United States lead? What services will be provided to non-US operators, and what will be the quid pro quo? How or will US “rules” be practically extended to foreign operators? Space debris: Are current mitigation guidelines sufficient? Debris mitigation guidelines (25 year rule) did not include a huge population surge, and usually assumed nation-state actors Will a “new space” company be in business in 25 years? Insurance: should actors in space be required to insure against … ? Second or third party liability? Debris generation? Should there be a “code of conduct?” What should a “prudent actor” in space do to avoid creating problems for other operators? What is the responsibility of the launching company/agency/nation for the actions of the payloads?

For Discussion Space operators’ business plans will be impacted by regulation, but regulations are not necessarily “bad” Example: A regulation requires an active location transponder on all spacecraft Negative impact: My cubesat design cannot accommodate that! Positive impact: New market for my transponder package! Some form of active space traffic management is probably inevitable Safety, debris control will be primary motives Will mostly focus on collision warning Launch regulations and licensing restrictions will probably be primary mechanism Will be aimed first at US businesses and agencies, but will likely set international precedents What form should regulations take? When? What should a responsible operator Code of Conduct contain?