Filed Electronically Ms. Marlene H. Dortch Secretary Federal Communications Commission 445 12Th Street, SW Washington, D.C. 2055

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Filed Electronically

Ms. Marlene H. Dortch Secretary Federal Communications Commission 445 12th Street, SW Washington, D.C. 20554 July 29, 2020 Regarding: Ex Parte Letter IB Docket No. 18-313: Mitigation of Orbital Debris in the New Space Age

Dear Ms. Dortch,

Pursuant to 47 C.F.R. § 1.1206, Planet Labs Inc. (“Planet”) submits this notice of a telephonic ex parte meeting on July 28, 2020, between representatives of Planet, Spire Global, Inc. (“Spire”), and Lynk Global, Inc. (“Lynk”), and representatives of the International Bureau, Satellite Division, to discuss concerns with the Order and Further Notice of Proposed Rulemaking in the above-captioned docket regarding Orbital Debris mitigation. During that meeting, Planet distributed and discussed the white paper and the slides, both presented now as attachments.

Attending on behalf of Planet were: Mike Safyan, Vivek Vittaldev, Jennifer Marcus, and Mark Mozena; on behalf of Spire: Michelle McClure; and on behalf of Lynk: Tony DeTora.

Attending on behalf of the International Bureau, Satellite Division: Jose Albuquerque, Shankar Persaud, Sam Karty, Merissa Velez, and Jay Whaley.

Please direct any questions or comments regarding this submission to the undersigned. Thank you for your time and consideration to this matter. Sincerely, Planet Labs Inc.

Mike Safyan Vice President, Launch [email protected] +1 (415) 225 9550

______

Planet Labs Inc. 645 Harrison St, Floor 4 Tel. +1 (415) 419-2194 www.planet.com San Francisco CA, 94107

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Planet Labs Inc. Ex Parte Letter IB Docket No. 18-313: Mitigation of Orbital Debris in the New Space Age July 29, 2020

cc: (via email) Jose Albuquerque, Satellite Division Chief Sankar Persaud, Engineering Branch Sam Karty, Engineering Branch Merissa Velez, Policy Branch Jay Whaley, Staff Attorney, Policy Branch

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July 24, 2020

Maneuverability Considerations for Satellites Operating in Low Earth Orbit

Authors: Mike Safyan, VP of Launch, Planet Labs Inc. Vivek Vittaldev, Lead Orbits R&D, Planet Labs Inc. Michelle McClure, Regulatory and Legislative Affairs Counsel, Spire Global Tony DeTora, VP of Government Affairs, Lynk

Summary and Introduction In this paper, the authors recommend that the FCC not adopt any specific maneuverability requirement. Nonetheless, to the extent the FCC elects to do so, the threshold for such a requirement should be consistent with the criteria adopted in the FCC’s 2020 Streamlining Licensing Procedures for Small Satellites (“Streamlining Procedures”). Specifically, if the FCC were to adopt a maneuverability requirement, it should do so only for: (i) non-geostationary satellite orbit (“NGSO”) systems, which operate at altitudes above 600 km; or (ii) NGSO systems, which have an aggregate satellite system mass over 1,800 kg and operate at altitudes over 400 km (i.e., “large” NGSO systems). See Table 1 below. For a satellite system subject to the maneuverability requirement, we propose a minimum maneuverability threshold equal to the predicted positional uncertainty forecasted with a 3-standard deviation confidence for the period of time at which it would be necessary for an operator to initiate a maneuver relative to the Time of Closest Approach (TCA).

The topic of satellite propulsion, and more generally satellite maneuverability, has been raised in several rounds of public comment regarding orbital debris mitigation for NGSO systems. Prescribing a specific type of technology that satellite operators are forced to utilize, e.g. propulsion systems, is out of sync with general U.S. regulatory practice. That alone is sufficient to dismiss such a requirement outright, in addition to several other reasons discussed in this paper, but a more generalized requirement for maneuverability could be considered under certain conditions. Due to the wide variety of satellite operators and satellite mission types that

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currently operate in Low Earth Orbit (LEO) and plan to do so in the future, a one-size-fits-all approach will not be sufficient. In keeping with the approach taken in the Streamlining Procedures, satellite fleet size, aggregate mass, and operating orbit must be taken into account.

We propose the following tiered approach for maneuverability requirements for all NGSO systems:

Maneuverability Requirement

System Characteristics Below 400 km 400 - 600 km Above 600 km

Total mass of the system is no more than 1,800 kg None None Yes

Total mass of the system is greater than 1,800 kg None Yes

Propulsion Systems are Not a Panacea When it comes to the construction of a satellite system, the FCC’s requirements have never been prescriptive, but rather define a capability or performance threshold that must be met. This gives the satellite manufacturer the flexibility to meet the criteria in a way that makes sense for that particular mission. For instance, the FCC does not mandate what type of antenna or amplifier technology a satellite operator must use, but rather operators are free to choose whatever technology suits their mission as long as they can demonstrate that their system meets the relevant requirements (e.g. power flux density thresholds, etc.). For this same reason, the FCC should not require operators to include propulsion systems on their satellites.

For one, there are several ways to alter a satellite’s orbital position in addition to propulsion, including solar sails, differential drag, electrodynamic tethers, and even ground based systems.1 In addition, not all propulsion systems are capable of the same performance. A propulsion system that fires once and can only produce a few Newtons of thrust would “check the box” of a

1 Although not common practice at the time of writing, ground-based lasers for orbital collision avoidance has been studied by various research groups. As an example, see NASA’s LightForce Photon-Pressure Collision Avoidance (Stupl, 2015) https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150000244.pdf

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propulsion requirement, but would certainly not meet the intention behind a collision avoidance capability that is sufficient and reliable under a variety of conditions. For all these reasons, a technology-agnostic maneuverability requirement must be employed.

Considerations for Small Systems The Streamlining Procedures already took into consideration many of these issues with respect to “small” NGSO systems in low orbits and any further orders must maintain consistency with those original conclusions. The Streamlining Procedures adopted rules that allow streamlined processing for systems with up-to 10 satellites, a mass of each individual satellite less than 180 kg, an orbital lifetime of maximum 6 years, and an operational altitude below 600km without any special requirement for maneuverability. Such streamlined treatment relies on the understanding that even if there were to be a collision involving a “small” NGSO system, a) the severity of that collision and the number of debris objects generated would be relatively low given the small size of the satellite(s), and b) the orbital lifetime of the debris fragments would also be relatively low since the satellite(s) were operating below 600 km, which is essentially the “self-cleaning” portion of orbit due to the force of atmospheric drag.2 It follows logically that the considerations with respect to number of satellites and satellite mass should be considered here.

It is also important to note that below a certain satellite size threshold, it would be impractical to adopt a meaningful propulsion system while maintaining the advantages that are unique to small satellites. For example, most satellites that adopt the 3U cubesat form factor or smaller do not have mass, volume, or power capacity to incorporate a meaningful propulsion system in addition to the main payload and the essentials of a satellite bus. Requiring a meaningful propulsion system would force satellite manufacturers to increase the size of the satellite, resulting in significant increases in material and launch costs. The additional design, testing, manufacturing, and operations costs would also be significant. Such a misguided propulsion requirement would essentially regulate a huge portion of small sats out of existence and put the U.S. industry at an extreme disadvantage.

2 Daniel Faber and Arthur Overlack. “Nanosatellite Deorbit Monitor.” 27th Annual AIAA/USU Conference on Small Satellites (2013). https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2916&context=smallsat

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General NGSO Threshold for Maneuverability The altitude threshold for a maneuverability requirement should be above 600 km, and this bears out from operational experience. For example, Planet has launched and operated over 300 Flock satellites in the orbital regime below 600 km since 2013 with no collisions to date. Spire has also launched over 100 Lemur satellites in a similar timeframe, also with no known collisions to date. Although both operators receive many notifications of predicted conjunctions, the predictions are based on very conservative assumptions and most are such low probability that no action is needed or taken.3 As an example, in 2019 Planet received a total of 78,443 Conjunction Data Messages (CDMs) from the 18th Space Control Squadron (SPCS) between a Flock satellite as the primary object and a non-Planet operated object as the secondary. Of that total, only 2,284 (2.9%) were above the “considerable risk” threshold of 1E-05 (one in one hundred thousand), and none of which resulted in an actual collision. In most cases, Planet did not need to take any action as the probability of collision decreased over time as trajectory predictions for one or both of the objects were refined with more observations.4 In a minority of cases, Planet would rotate its satellite to present the minimum surface area towards the potential collision in order to further reduce the probability of collision. Similarly, Spire has historically received conjunction notices above an actionable threshold of 1E-04 (one in ten thousand) approximately twice per week. When these notices are received, Spire coordinates with the other party (if an active satellite) to share ephemeris data. Data sharing between parties refines the conjunction analysis and allows the other party, if capable of maneuvering, to take evasive actions, and no cases resulted in an actual collision.

While Planet and Spire’s operational experiences are statistically relevant based on what the orbital environment below 600 km has been like to-date, it’s well known that a number of Large NGSOs, including “megaconstellations” with thousands of planned satellites, have either already begun operations at altitudes below 600 km, or have plans to do so. These systems are fundamentally changing the sub-600 km orbital regime and are addressed in the next section.

3 Probability of Collision in the Join Operations Center (2016) https://www.space- track.org/documents/How_the_JSpOC_Calculates_Probability_of_Collision.pdf 4 Planet makes all of its updated satellite ephemeris data publicly available at https://ephemerides.planet- labs.com/

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Considerations for Large NGSO For Large NGSO systems, e.g. SpaceX’s Starlink or Amazon’s Kuiper, we believe that maneuverability should be a requirement for any orbit above 400 km. As of yet, there has been no widely agreed on definition of what constitutes a Large NGSO. We propose to follow the logic of the Streamlining Procedures and recommend the following definition:

A Large NGSO system is a satellite fleet whose total free-flying mass at any given time, including any non-operational satellites remaining in orbit, is above 1,800 kg.5

For example, a system of 20 on-orbit 1U cubesats with a mass of 1 kg each would have a total fleet mass of 20 kg and thus would not require maneuverability if operating below 600 km. On the other hand, a fleet of 5 satellites at 500 kg each or a fleet of 500 satellite at 300 kg each would require maneuverability if operating anywhere above 400 km. In line with the logic followed in the Streamlining Procedures, such a delineation addresses the difference in severity of collisions between different types of systems, i.e. the severity of impact with a 1 kg cubesat is much lower than with a 500 kg satellite, both in terms of number of debris fragments likely to be generated, and the orbital lifetime of those fragments. Given that Large NGSO systems as defined have such outsized impacts on whatever orbital regime they operate in, it only follows that they should be held to a higher standard of operation.

Proposed Threshold for Maneuverability If the exact size, shape and position of every object in orbit could be precisely known, and the trajectory could be perfectly forecasted several days into the future, then all potential collisions could be identified with very high confidence and a maneuver of tens of meters by one of the objects would be sufficient to avoid any collision in almost all cases. In practice, each object has some degree of positional uncertainty and prediction uncertainty, thus forcing satellite operators to take a probabilistic approach in assessing conjunctions; an approach that is heavily influenced by the degree of positional and predictive uncertainties.

Currently, publicly available TLEs provided by the 18th SPCS via the Space-Track space catalogue can range from hundreds of meters to several kilometers. However, satellite operators often have much better positional estimates of their satellites using a number of

5 1,800 kg comes from multiplying 10 (satellites) by 180 (kilograms).

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refining techniques, including radio ranging, on-board GPS, or supplemental tracking measurements from third party sources. As an example, Planet’s SkySat satellites maintain a positional uncertainty of approximately 100 meters by continuously running onboard GPS, and Planet’s Flock satellites maintain a positional uncertainty of 100 to 300 meters when running periodic onboard GPS measurements and radio ranging, a clear improvement over the worst- case scenarios from the space catalogue TLEs. Furthermore, the positional uncertainty of any on-orbit object, functional or otherwise, can be reduced to the low 100s of meters by activating additional observations by the 18th SPCS, or utilizing supplemental tracking data from a commercial service provider such as LeoLabs.6

Prediction uncertainty, another major factor of calculating probability of collision, depends on a variety of variables including satellite ballistic coefficient, orbital altitude, and solar activity. Very large satellites at high altitudes are less susceptible to perturbing forces, such as fluctuations in atmospheric drag, compared to small satellites at lower altitudes. For example, ICESat, with a mass of 970 kg and operating at approximately 595 km, was shown to have 3 to 4 day prediction uncertainties of approximately 300 meters under 2003 solar conditions (modest solar flux).7 On the other hand, Planet Flock-series satellites that are 3U cubesats with mass of approximately 5 kg and operate close to 500 km altitude, were shown to have a 3-standard deviation (or 3-sigma) 48 hour prediction uncertainty of approximately 5 km under 2017 solar conditions (modest solar flux) and 2.7 km under 2019 solar conditions (low solar flux). These are only point examples, and predictive uncertainty is even higher under maximum solar flux conditions, however it should be noted that the effectiveness of differential drag also increases under high solar activity conditions, which is not true of systems solely relying on traditional propulsion. Regardless, each satellite system will have different predictive uncertainties under different conditions, and a one-size-fits-all approach for defining predictive uncertainty does not make sense.

Taking the above into account, it follows that if a satellite has the ability to maneuver farther out than its predictive uncertainty in the relevant time period, it should be able to successfully mitigate most conjunction scenarios. Thus, for a satellite system subject to the

6 From LeoLab’s website: How is What LeoTrack provides different than a TLE? https://www.leolabs.space/tracking-and-monitoring/#how-is-what-leotrack-provides-different-than-a-tle2 7 David Vallado. “An Analysis of State Vector Prediction Accuracy.” (https://www.agi.com/getmedia/60f1f2a7-3a41-4a7c-8d48-2de7d58a0d71/An-Analysis-of-State-Vector- Prediction-Accuracy.pdf?ext=.pdf))

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maneuverability requirement, we propose a minimum maneuverability threshold equal to the predicted positional uncertainty forecasted with a 3-standard deviation confidence for the period of time at which it would be necessary for an operator to initiate a maneuver relative to the Time of Closest Approach (TCA). In other words, the satellite “must be able to move outside its uncertainty bubble in time to avoid the conjunction.”

For example, a satellite system with a high thrust propulsion capability could have a go/no-go maneuver decision point at 3 hours before TCA, and the predicted positional uncertainty with 3- sigma confidence for that satellite at TCA minus 3 hours is 500 meters. Thus, the minimum maneuverability for that system under those solar conditions would be 500 meters within 3 hours. As another example, a satellite with a low-thrust electric propulsion system or a satellite using differential drag may require a 48 hour go/no-go decision timeline since those types of maneuvers take longer, and thus the minimum maneuverability requirement would correlate with the 3-sigma predicted uncertainty at TCA minus 48 hours for that system. The satellite operator would have to demonstrate sufficient maneuverability under all orbital and solar conditions encompassing the mission duration.

Instead of imposing a blanket maneuverability threshold (e.g. 1 km in 48 hours) that may not be appropriate for all orbits, solar conditions, and satellite types, the above described criteria is “tailor fitted” to the particulars of each mission and also naturally evolves as better tracking and predictive capabilities come online. Full implementation of the Space Fence, better atmospheric models, and the expansion of commercial providers like LeoLabs, etc. could improve positional predictions in the future.

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Summary and Conclusion Small satellite systems have been operating at altitudes below 600 km for many years without issue. As was already decided in the FCC Streamlining Procedures, maneuverability should not be a requirement for small satellite systems operating below 600 km given the low severity and environmental impact if there were to be a collision. Large NGSO systems, including megaconstellations, will fundamentally change the nature of any orbit they occupy, and thus should be held to a higher standard. We propose the following tiered maneuverability system, with the required maneuverability threshold being equivalent to the predicted positional uncertainty forecasted with a 3-standard deviation confidence for the period of time at which it would be necessary for an operator to initiate a maneuver relative to the Time of Closest Approach (TCA):

Maneuverability Requirement

System Characteristics Below 400 km 400 - 600 km Above 600 km

Total mass of the system is no more than 1,800 kg None None Yes

Total mass of the system is greater than 1,800 kg None Yes

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Planet - Spire - Lynk Presentation to FCC IB on NGSO Maneuverability July 28, 2020 DocuSign Envelope ID: B86E2333-EF7C-442D-AA08-7EEC971A9CB5

Planet Labs Inc. (Planet)

Planet is a space and data analytics company that designs, manufactures and operates the world’s largest fleet of remote sensing satellites. Planet licenses its satellite imagery and derived products to a variety of government, commercial, non- profit and research customers around the world.

● U.S. company headquartered in San Francisco, CA with offices in Washington D.C. and Berlin, Germany ● Founded in 2010, approximately 500 employees globally ● Flock constellation (Call Sign S2912) ○ 3U cubesats, 5 kg, 358 launched, 229 on-orbit, 134 currently active ● SkySat constellation (Call Sign S2862*) ○ Mini-fridge size, 110 kg, 18 on-orbit & active (3 more planned) ● The two fleets operate primarily between 400 and 600 km 2 DocuSign Envelope ID: B86E2333-EF7C-442D-AA08-7EEC971A9CB5

Spire Global, Inc.

Spire is a next generation data and predictive analytics company that collects data from space to solve problems on Earth. Spire identifies, tracks and predicts the movement of the world’s resources and weather systems.

● US company, headquarters in San Francisco; offices in DC, Boulder, Luxembourg, Glasgow & Singapore ● Founded in 2012, approximately 225 employees ● Holds U.S. earth station license for its LEMUR constellation and market access grant for its MINAS constellation allowing for not more than 175 simultaneously operational satellites (S2946; SAT-AMD-20180102-00001; S3045; SAT-PDR-20190321-00018)

● Currently 88 satellites on orbit; 4.5 kg max total mass of satellites at launch 3 DocuSign Envelope ID: B86E2333-EF7C-442D-AA08-7EEC971A9CB5

Lynk Global, Inc.

Lynk is a mobile network technology company focused on providing universal connectivity for the mobile phone. Lynk’s patented and proven technology allows standard mobile phones, without any changes in hardware or software, to be connected virtually anywhere on the globe using our low-earth-orbit nanosatellites. The growing Lynk network represents the best way forward to broadband connectivity everywhere, including the most isolated areas. We are the world’s safety net.

● US company, headquarters in Falls Church, VA ● Founded in 2017 ● Approximately 35 employees

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Maneuverability Considerations for NGSO Systems

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Propulsion is not a Panacea

1. Other FCC requirements are not technology specific. a. E.g. Part 47 PFD limits do not require specific types of antenna or amplifier technology. 2. Maneuverability can be achieved via solar sails, differential drag, electromagnetic tethers, etc. 3. Very small propulsion systems may not be able to provide meaningful thrust or an adequate number of firings for collision avoidance. 4. Requiring propulsion systems may regulate U.S. commercial cubesats out of existence. 5. Instead, maneuverability capability should be considered.

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NGSO Systems Operating Below 600 km

1. Small satellite systems at altitudes below 600 km have largely been operating without issue to-date. 2. Severity/Consequence of collisions with small objects is comparatively low. a. Collision with a small object may be mission-terminating for an individual satellite, but the environmental impact to the surrounding orbit is low. b. ~1 million objects > 1 cm estimated in LEO; small sats are a drop in the bucket and the environmental risk is already prevalent. 3. Below 600 km is the “self-cleaning” portion of LEO due to atmospheric drag. 4. Following the logic of the FCC’s 2019 Streamlining License Procedures for Small Satellites, we maintain that small satellite systems operating below 600 km should be exempt from any maneuverability requirement. 5. "Large NGSOs”, and espically megaconstellations, should be held to a higher standard. 7 DocuSign Envelope ID: B86E2333-EF7C-442D-AA08-7EEC971A9CB5

Definition of “Large NGSO” and Additional Responsibilities

1. Large NGSO systems, e.g. SpaceX Starlink or Amazon Kuiper, have a disproportionately sized impact to the 400 - 600 km orbital regime. a. Both in terms of number of objects, and also consequence of collision(s) due to larger satellites carrying propellant. 2. Must be held to a higher standard and require maneuverability anywhere above 400 km. 3. Following the logic of the FCC’s 2019 Streamline Order (up-to 10 satellites, up-to 180 kg individual satellite mass), we propose the following definition: A Large NGSO system is a satellite fleet whose total free-flying mass at any given time, including any non-operational satellites remaining in orbit, is above 1,800 kg.

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Probability of Collision

1. Positional estimates and prediction uncertainties are important factors in calculating probability of collision 2. 18th SPCS space catalogue is the standard, but positional estimates can be refined by onboard GPS, radio ranging, ground based laser measurements, or 3rd party commercial sources (e.g. LeoLabs) 3. Prediction uncertainties vary by orbit, satellite characteristics, solar conditions, and uncertainties grow the farther out you predict a. A 1 ton satellite at 600 km is less perturbed by atmospheric forces compared to 5 kg satellite at 500 km where the atmosphere is thicker and more dynamic 4. Satellite operators commonly use 1E-04 or 1E-05 as threshold for “concerning” probability of collision a. Operators may also take into account predicted severity of collision 9 DocuSign Envelope ID: B86E2333-EF7C-442D-AA08-7EEC971A9CB5

Proposed Threshold for Maneuverability

For a satellite system subject to the maneuverability requirement, we propose a minimum maneuverability threshold equal to the predicted positional uncertainty forecasted with a 3-standard deviation confidence for the period of time at which it would be necessary for an operator to initiate a maneuver relative to the Time of Closest Approach (TCA).

In other words, the satellite “must be able to move outside its uncertainty bubble in time to avoid the conjunction.”

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Example - 2017 Flock Conjunction Alerts

Under 2017 solar conditions, in-track estimate 48 hours in the future with 3-sigma (99.7%) confidence is 5 km.

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Example - 2019 Flock Conjunction Alerts

Under 2019 solar conditions, in-track estimate 48 hours in the future with 3-sigma (99.7%) confidence is 2.7 km.

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Maneuverability Threshold - Further Discussion

1. The goal should be to define the minimum maneuverability requirement to minimize the burden on satellite operators. 2. A static requirement (e.g. 1 km in 48 hours) might not be appropriate in all cases. a. Different systems have different maneuvering timelines (e.g. a high-thrust propulsion system may have a go/no-go at TCA minus 3 hours, but a low-thrust electric propulsion system may need several days). b. Prediction uncertainty varies with timeline, satellite characteristics, solar activity, etc. 3. The “move outside your bubble” rule tailor-fits each mission. 4. Also allows for improved tracking and predictive capability (e.g. Space Fence, LeoLabs expansion, etc.) to naturally evolve the rule in the future. 13 DocuSign Envelope ID: B86E2333-EF7C-442D-AA08-7EEC971A9CB5

Summary of Recommendation

Maneuverability Requirement System Characteristics Below 400 km 400 - 600 km Above 600 km Total mass of the system is no more than 1,800 kg None None Yes Total mass of the system is greater than 1,800 kg None Yes

Maneuverability Threshold: Must be able to move outside your uncertainty bubble in time to avoid the collision.