Washington, D.C., January 5, 2026
Before the Federal Communications Commission,
Washington, D.C. 20554
In RE: Space Bureau and Wireless Telecommunications Bureau Accept for Filing Application of SpaceX Requesting NGSO MSS Authorization and Supplemental Coverage from Space Authorization and Seek Comment on Waivers
The American Astronomical Society [1] (AAS), the major organization of professional astronomers in the United States representing over 8500 members, appreciates the opportunity to provide comments in response to this Public Notice (DA 25-1018) regarding an application from Space Exploration Technologies Corp. (SpaceX) for a new non-geostationary orbit (NGSO) satellite constellation providing supplemental coverage from space (SCS) and mobile-satellite service (MSS) operations.
I. Introduction
The application (SAT-LOA-20250916-00282) and amendment (SAT-AMD-20251125-00339) filed by SpaceX request authority to launch and operate an independent 15,000-satellite very low-Earth orbit (VLEO; <400 km altitude) constellation providing direct-to-device SCS and MSS service to customers in the United States and internationally (“SpaceX SCS/MSS System”).
Many of the bands requested for this new SCS/MSS System were previously requested by SpaceX for the Starlink Gen1 and Gen2 systems. Of note,
• SCS operations within the United States were previously authorized in the 1910-1915 MHz (uplink) and 1990-1995 MHz (downlink) frequency bands for Starlink Gen2. [2]
• MSS operations in the 1610.0-1617.775 MHz, 2000-2020 MHz, 2020-2025 MHz (uplink) and 2180-2200 MHz, 2483.5-2500.0 MHz (downlink) frequency bands were previously dismissed for Starlink Gen2 [2] because the Federal Communications Commission (FCC) determined that the 1.6/2.4 GHz and 2 GHz bands could not accommodate additional MSS applications. [4] These bands have since been re-requested for Starlink Gen2. [5] Action is pending.
• FSS operations in the 42.0-42.5 GHz (downlink) and 51.4-52.4 GHz (uplink) bands were previously dismissed for Starlink Gen2 [6,7] because these bands are not allocated to satellite services. These bands have since been re-requested for Starlink Gen2 [8] and are being considered for expanded satellite service operations under the “Satellite Spectrum Abundance” Notice of Proposed Rulemaking [9] (NPRM). Action is pending.
• In addition to the 42.0-42.5 GHz (downlink) and 51.4-52.4 GHz (uplink) bands, FSS operations are requested in the 29.1-29.5 GHz, 30.0-31.0 GHz, 92-94 GHz, 94.1-100 GHz, 102.0-109.5 GHz, 111.8-114.25 GHz (uplink) frequency bands. Similarly, these bands are not allocated to satellite services—in fact, many of them are primary allocations to the Radio Astronomy Service (RAS)—but are being considered for expanded satellite service operations under the “Satellite Spectrum Abundance” NPRM. Action is pending.
II. Radio Astronomy
Because the SpaceX SCS/MSS System requests the same frequency bands which are the subject of the “Satellite Spectrum Abundance” NPRM, we hold the same position regarding expanded use of bands not allocated to the satellite services. On behalf of the United States astronomical community, we emphasize that frequency bands allocated to the Radio Astronomy Service (RAS) both domestically and internationally must be protected in accordance with the applicable domestic and international regulations. We provide as an annex to these comments a list of the relevant frequency bands impacted by the SpaceX filings that are allocated to the RAS on a primary or secondary basis, as well as those for which all practicable steps to protect the RAS are urged in accordance with the footnotes to the United States Table of Frequency Allocations (47 CFR § 2.105) and the International Telecommunication Union Radiocommunication Sector Radio Regulations (ITU-R RR). These bands are protected globally in recognition of their value for understanding the universe around us.
In addition to this foundational need to protect RAS frequency allocations in accordance with domestic and international regulations, the direct-to-device service that the SpaceX SCS/MSS System intends to provide necessitates enhanced coordination to protect radio astronomy operations. The FCC, recognizing that astronomy and scientific research serve the public interest, requires that satellite operators negotiate a mutually agreeable Coordination Agreement with the U.S. National Science Foundation (NSF) to mitigate impacts of their services on RAS operations. SpaceX was the first operator to finalize one of these Coordination Agreements with the NSF in 2023 [10] and has been working with the NSF on an ongoing basis to develop new radio frequency interference mitigation methods, for which the astronomy community is eminently grateful. This has included coordination surrounding direct-to-device service, whose operational model of connecting directly to user equipment effectively negates the historical approach astronomers have taken to protect their systems in siting observatories far from population centers where more radiocommunication infrastructure is employed. We urge that the FCC continue to facilitate positive coordination efforts between SpaceX and the NSF, especially regarding direct-to-device operations.
Last, we remind the Commission of the recent discovery by radio astronomers of unintended electromagnetic radiation (UEMR) associated with operating Starlink satellites, in which low-frequency broad- and narrow-band emissions appear to originate from satellite electronics. [11] The astronomy community appreciates the ongoing coordination between SpaceX and the NSF surrounding this novel challenge. However, we note that due to the uncontrolled nature of this phenomenon, proliferation of such a large constellation in VLEO risks creating a pervasive UEMR background in Earth orbit as the issue scales with constellation size. Furthermore, UEMR from Starlink satellites operating at notional altitudes of ~500-600 km has already been detected in radio telescopes at levels higher than RAS protection criteria established in Recommendation ITU-R RA.769-2 and other ITU documents, and the significantly lower 320-340 km altitude of the proposed SCS/MSS System will cast much stronger UEMR signals on the ground. With these risks in mind, and in the spirit of fostering collaborative problem-solving in space, we also urge that the FCC continue to facilitate effective coordination efforts between SpaceX and the NSF regarding current and future unintended electromagnetic radiation (UEMR).
III. Optical Astronomy, Space Debris, and VLEO Sustainability
Although the optical spectrum currently lacks the regulatory structure through which radio frequency operations are coordinated, the impacts of proliferated satellite constellations on optical astronomy are a known, growing, and serious issue within the astronomy community.
As with UEMR, optical interference into astronomy systems scales with constellation size as more hardware is deployed in Earth orbit. Astronomers are actively studying this issue and working with satellite operators to determine best practices—there is evidence that because satellites operating at lower orbital altitudes spend more time in Earth’s shadow, they do not as frequently reflect sunlight to the ground, especially during the darkest portions of the night when astronomy research observations are of the highest quality. [12,13] However, lowering satellite altitudes is not a comprehensive solution to optical astronomy interference, as 1) astronomers often conduct critical observations during twilight before the night begins, which is when VLEO satellites appear brightest just before they set in Earth’s shadow, 2) the much larger numbers of sunlight streaks from VLEO satellites significantly hampers the ability to detect threats such as Earth-crossing asteroids, 3) significantly increasing the number of satellites in the night sky may negate the benefits gained from operational mitigations like choosing lower orbital altitudes, and 4) VLEO satellites are outside the Earth’s shadow for a large fraction of the night during the summer at latitudes higher/lower than 45 degrees N/S (respectively) and will severely impact summer research operations at these locations. [14]
The astronomy community is again extremely grateful to the FCC for requiring that coordination on optical and radio astronomy be incorporated into the NSF Coordination Agreement process, as this facilitates the collaborative problem solving necessary to tackle novel challenges like UEMR and optical interference. We urge the FCC to continue this practice of coordination agreements, such that astronomical interests and federal investments in astronomical facilities can be protected alongside support for the commercial space industry.
It is important to note though that the concerns surrounding optical astronomy preservation are often the same as those raised in broader conversations on space sustainability and space domain awareness, particularly regarding the congestion of orbital space and risk of debris creation and proliferation. This issue is only amplified when considering large constellations in VLEO, like the proposed SpaceX SCS/MSS system, as there is simply less space in VLEO and the risk of collisions is therefore higher than in more distant orbits. Recently, SpaceX reported a close encounter of Starlink satellites with a satellite recently launched by China which could have resulted in a collision [15], and a few days later SpaceX reported a satellite malfunction that generated orbital debris and sent the failed satellite into an uncontrolled decaying orbit. [16] These close calls and operational failures will only occur more often if there are more objects occupying Earth orbit and the potential consequences must be carefully considered, including cascading damage to other operating systems caused by the ejection of new space debris.
While operating at these very low altitudes does make it so that debris de-orbits relatively quickly, it also means that atmospheric drag on operating satellites will require more frequent orbital raising/correction, and will thus require more on-board propellant for these maneuvers and could result in even shorter operational lifetimes for these satellites. With more than one Starlink satellite re-entering per day on average over the past few months, the natural infall rate of many different metals has already been exceeded. These chemical changes to the stratosphere are being measured and initial studies show that this could result in ozone depletion. [17,18] Disposing of satellites in Earth’s atmosphere at an even higher rate will exacerbate this pollution, and if these satellites do not burn up completely, ground casualty risks rise as well. [19]
Aside from risking physical damage to other space-based systems or even rendering full sections of Earth orbit unfit for satellite deployment, particulate space debris act as a cloud of small reflecting objects that will increase the overall brightness of the night sky, contributing to optical astronomy interference ubiquitously and in a way such that mitigation is practically impossible. Thus, it is essential that coordination on optical astronomy continues not only to benefit the astronomy research community, but also to help the satellite industry anticipate and avoid potential threats to the sustainable use of Earth orbit.
IV. Concluding Remarks
The 15,000-satellite SpaceX SCS/MSS system, in combination with the ~30,000 authorized satellites for Starlink Gen2 that may also operate below 400 km altitude, [20] comprise an unprecedented expansion of the use of VLEO for commercial service even before considering constellations that may be planned by other countries. The range of potential negative externalities in developing VLEO so quickly is vast, ranging from novel radio spectrum challenges, to potential loss of access to the night sky, and even to the overall sustainability of VLEO operations. Human spaceflight concerns must be taken into account as well, as the International Space Station currently operates between 350-400 km altitude, which makes any VLEO space debris generation a threat to safety-of-life. We hope that the FCC takes careful consideration and a broad perspective in determining operational conditions for any proliferated VLEO satellite constellation, and hope that the astronomy community can continue to help guide satellite operators towards a sustainable future for space operations.
Thank you for your consideration.
Dara Norman, PhD
President, American Astronomical Society
References
- ICFS File No. SAT-MOD-20230207-00021; Space Exploration Holdings, LLC Request for Deployment and Operating Authority for the SpaceX Gen2 NGSO Satellite System, Order and Authorization, DA 24-1193 (2024).
- ICFS No. SAT-MOD-20230207-00022; Space Exploration Holdings, LLC Application for Modification of Authorization for the SpaceX Gen2 NGSO Satellite System to Add a Mobile-Satellite Service System, Order, DA 24-300 (2024).
- Amendment of the Commission’s Rules to Establish Rules and Policies Pertaining to a Mobile Satellite Service in the 1610-1626.5/2483.5-2500 MHz Frequency Bands, Report and Order, 9 FCC Rcd 5936 (1994), on reconsideration, Memorandum Opinion and Order, 11 FCC Rcd 12861 (1996); Review of the Spectrum Sharing Plan Among Non-Geostationary Satellite Orbit Mobile Satellite Service Systems in the 1.6/2.4 GHz Bands, Amendment of Part 2 of the Commission’s Rules to Allocate Spectrum Below 3 GHz for Mobile and Fixed Service to Support the Introduction of New Advanced Wireless Services, Including Third Generation Wireless Systems, Report and Order, Fourth Report and Order and Further Notice of Proposed Rulemaking, 19 FCC Rcd 13386 (2004); Spectrum and Service Rules for Ancillary Terrestrial Components in the 1.6/2.4 GHz Big LEO Bands, Review of the Spectrum Sharing Plan Among Non-Geostationary Satellite Orbit Mobile Satellite Service Systems in the 1.6/2.4 GHz Bands, Second Order on Reconsideration, Second Report and Order, and Notice of Proposed Rulemaking, 22 FCC Rcd 19733 (2007); Service Rules for Advanced Wireless Services in the 2000-2020 MHz and 2180-2200 MHz Band, Report and Order and Order of Proposed Modification, 27 FCC Rcd 16102 (2012); 47 CFR §§ 25.112(a), 25.114(a)(1).
- ICFS File Nos. SAT-MOD-20250514-00119, SAT-MOD-20250611-00144
- ICFS File No. SAT-LOA-20170301-00027; Space Exploration Holdings, LLC Application for Approval for Orbital Deployment and Operating Authority for the SpaceX V-band NGSO Satellite System, Memorandum Opinion, Order and Authorization, FCC 18-161 (2018).
- ICFS File No. SAT-MOD-20230322-00062; Satellite Licensing Division and Satellite Programs and Policy Division Information, Actions Taken, DA 23-997 (2023)
- ICFS File No. SAT-AMD-20241017-00228.
- FCC 25-29; SB Docket No. 25-180; GN Docket No. 22-352; WT Docket No. 23-158; GN Docket No. 14-177.
- Di Vruno et al., “Unintended electromagnetic radiation from Starlink satellites detected with LOFAR between 110 and 188 MHz”, Astronomy & Astrophysics, 676, A75 (2023) https://www.aanda.org/articles/aa/full_html/2023/08/aa46374-23/aa46374-23.html
- Snyder & Tyson, “Satellite Streak Brightness Variation with Orbit Height” (2025) https://arxiv.org/abs/2505.06424
- “Report on LEO satellite impacts on ground-based optical astronomy for the Rubin Observatory LSST” (2025) https://arxiv.org/abs/2509.19758
- Lawler, Boley & Rein, “Visibility Predictions for Near-future Satellite Megaconstellations: Latitudes near 50° Will Experience the Worst Light Pollution”, The Astronomical Journal, 163, 21 (2022) https://iopscience.iop.org/article/10.3847/1538-3881/ac341b
- Schulz et al., “Space waste: An update of the anthropogenic matter injection into Earth atmosphere”, Advances in Space Research, submitted (2025). https://arxiv.org/abs/2510.21328
- Maloney et al., “Investigating the Potential Atmospheric Accumulation and Radiative Impact of the Coming Increase in Satellite Reentry Frequency”, Journal of Geophysical Research: Atmospheres, 130, 6 (2025) https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JD042442
- Wright, Boley & Byers “Airspace closures due to reentering space objects” Nature Scientific Reports, 15, 2966 (2025) https://www.nature.com/articles/s41598-024-84001-2
- Space Exploration Holdings, LLC Request for Deployment and Operating Authority for the SpaceX Gen2 NGSO Satellite System, Order and Authorization, DA 24-1193 (2024)