Operational Amateur Radio and Educational Satellites in Earth Orbit

I. Scope, Methodology, and Authoritative Data Sources

“Operational” in this report means: a spacecraft is in Earth orbit and is reported as providing two-way amateur communications (transponder/repeater) or is consistently transmitting telemetry/beacons with published demodulation parameters. Because on-orbit configuration changes (power budgets, eclipse season, command schedules, and failures), readers should treat any static list as a snapshot and verify against live status sources.

The following sources are treated as primary for near-real-time operations: AMSAT’s live status page (crowd-sourced daily reports) [1], AMSAT’s frequency/mode summaries for FM and linear satellites [2], [3], ARISS station status and contact frequencies for ISS operations [4], [5], and the SatNOGS database for transmitter definitions and operational metadata [6]. For broader catalog coverage (including educational spacecraft with amateur payloads), AMSAT’s searchable amateur satellite database (compiled from JE9PEL/KFØIA and SatNOGS) is recommended [7].

II. Operational Satellite Functions in the Amateur and Educational Ecosystem

A. Analog FM repeaters (“FM birds”)

These typically implement a narrowband FM uplink and a narrowband FM downlink with a fixed cross-band translation (commonly VHF uplink to UHF downlink). Many are optimized for low-complexity user equipment (handheld transceivers and handheld Yagi antennas). Examples include long-running community satellites (e.g., SO-50, AO-91) and newer PocketQube/CubeSat missions (e.g., SO-124, SO-125) [2], [8], [9].

B. Linear transponders (SSB/CW “passband”)

Linear transponders provide a receive “uplink passband” and re-transmit a “downlink passband,” enabling multiple simultaneous SSB/CW users. These are often categorized by band pairing and inversion behavior (e.g., V/u, U/v; non-inverting or inverting). Examples include AO-7, FO-29, RS-44, JO-97, and QO-100 (GEO, but operationally similar for narrowband SSB/CW) [3].

C. Digital store-and-forward, digipeaters, and experiment downlinks

Digital payloads may provide AX.25 packet (including APRS), store-and-forward message services, or telemetry downlinks using BPSK/GMSK/FSK families. A contemporary CubeSat trend is the use of CSP (CubeSat Space Protocol) at the network layer with GMSK at the physical layer (e.g., the UNSW-EC0 QB50 spacecraft beaconed GMSK 4k8 with CSP framing) [10].

D. Telemetry and educational outreach payloads

Many educational missions prioritize “easy-to-copy” beacons, accessible decoding software, and a stable telemetry format to support global participation. AO-73 (FUNcube-1) explicitly targets educational outreach with a 1200 baud BPSK beacon and associated ground decode software [11].

E. The ISS as an operational education platform

Amateur Radio on the International Space Station (ARISS) supports voice contacts, packet, SSTV events, and an FM cross-band repeater when configured. ARISS publishes station status and nominal frequencies (e.g., 145.800 MHz downlink for voice/SSTV; 145.825 MHz packet; 145.990/437.800 MHz repeater pair) [4], [5], [12].

III. Frequency Plans, Bands, and Protocol Families

Amateur-satellite missions rely on coordinated use of bands allocated to the Amateur-Satellite Service and adjacent amateur allocations where permitted. Frequency coordination is typically pursued through the IARU satellite coordination process; coordination guidance and request instructions are published by IARU [13], [14].

A. Common uplink/downlink band pairings

• VHF uplink / UHF downlink (V/U): widely used for FM repeaters and packet (e.g., AO-91, SO-124) [2], [8].
• UHF uplink / VHF downlink (U/V): used by many linear transponders and some repeater architectures [3].
• S-band uplink / X-band downlink (S/X) for GEO narrowband: QO-100 narrowband and wideband payloads are prominent examples [3].

B. Protocol families you will encounter

• Analog FM voice: narrowband FM; sometimes with CTCSS/PL for uplink access [2], [12].
• SSB/CW (linear): passband operation; uplink often LSB and downlink USB in inverting configurations [3].
• AX.25 / APRS: packet radio used for telemetry, messaging, and digipeating; ISS packet operations are a canonical reference [5].
• BPSK/GMSK/FSK variants: common for telemetry at 1k2–9k6 and beyond; SatNOGS catalogs transmitter modes at scale [6].
• CSP: frequently used in educational CubeSats as a network protocol; documented in operational practice by QB50/UNSW-EC0 [10].

IV. Representative Operational Satellites: Frequencies, Modes, and Access Notes

Tables I–III provide a representative (not exhaustive) set of operational satellites that are widely used by amateur operators and/or are explicitly educational. For an expanded and searchable catalog, use AMSAT’s amateur satellite database [7] and the SatNOGS DB [6].

Table I — Representative FM repeaters (cross-band)

Table II — Representative linear transponders (SSB/CW passband)

Table III — Representative digital telemetry and educational downlinks

For satellites not listed in Tables I–III (including telemetry-only, APRS-only, or intermittent payloads), use AMSAT’s satellite database [7] and validate operational state with AMSAT live status reports [1] and SatNOGS “alive transmitters” metadata [6].

V. Sensors and Telemetry: What Is Measured and Why

Amateur and educational satellites typically downlink both “housekeeping” telemetry (for flight safety and operations) and payload telemetry (for mission science/education). Commonly observed sensor classes include:

A. Electrical power system (EPS) and thermal health

• Battery voltage/current, charge/discharge state, solar panel currents, bus voltages.
• Temperature sensors at critical subsystems (battery, radio PA/LNA, onboard computer, payload boards).

Operational telemetry tooling for AMSAT Fox spacecraft demonstrates typical downlinked housekeeping channels and procedures; Fox telemetry is also carried “data-under-voice” during FM transponder operation in some configurations [19].

B. Attitude determination and control (ADCS) sensors

Many small satellites include IMU-class sensors (gyros, accelerometers) and magnetometers to support detumble and attitude stabilization. Public Fox spacecraft health telemetry pages illustrate typical channels including gyro temperature, rotation rates, accelerations, and magnetometer readings [20].

C. Sun and environmental sensors

Educational CubeSats frequently incorporate sun sensors and panel temperature sensors to correlate power generation with attitude and thermal behavior. The FUNcube handbook describes solar panels with sun and temperature sensors as part of the system design [21].

D. Educational and science payload sensors (examples)

• Thermosphere composition: The UNSW QB50 spacecraft carried an Ion Neutral Mass Spectrometer for composition measurements [10].
• GNSS experimentation: The same mission describes an in-space GPS board experiment and radio occultation sounding [10].
• Re-entry and drag measurements: QB50 studied re-entry by measuring parameters such as onboard temperature and deceleration [10].
• STEM “physics-in-space” experiments: Educational material associated with FUNcube missions discusses classroom-oriented experiments related to heat transfer and radiation (e.g., Leslie’s Cube demonstrations) [22].
• Imaging for outreach: Some amateur payload spacecraft incorporate low-resolution cameras for Earth imaging alongside amateur communications capability (e.g., QMR-KWT-2 description in SatNOGS) [18].

VI. Design and Operations Resources

The following resources are broadly useful for amateur/educational mission design, licensing/coordination, and operations:

A. Operations and frequency planning

• AMSAT live status page (crowd-sourced operational status) [1].
• AMSAT frequency summaries for FM and linear satellites [2], [3].
• ARISS station status and contact guidance for ISS operations [4], [5].
• IARU coordination guidance (process and request documentation) [13], [14].

B. Databases and ground-station ecosystem

• SatNOGS DB for transmitter definitions and operational metadata (including modulations, baud rates, and frequency assignments) [6].
• SatNOGS project documentation for building low-cost, open-source ground stations and contributing observations [23].
• AMSAT amateur satellite database for searchable, linkable satellite frequency and mode listings [7].

C. Small satellite mechanical standards

• CubeSat Design Specification (Cal Poly) defining mechanical interfaces, form factors, and safety constraints [24].

D. Flight software starting points

• OpenSatKit (NASA cFS-oriented open-source flight software platform) for CubeSat-scale missions and education [25], [26].

VII. Opportunities for Low-Cost Launches and Deployments

A. Rideshare on large launch vehicles (commercial)

The dominant price anchor for low-cost access to LEO for many CubeSats is commercial rideshare, where payloads buy capacity on scheduled missions. SpaceX publishes standardized smallsat rideshare pricing and mass-to-orbit tiers; consult the current program page for the latest terms and pricing [27]. From a programmatics perspective, rideshare often optimizes cost and schedule certainty at the expense of precise orbital insertion (unless paired with an orbital transfer vehicle).

B. Educational launch programs (government / institutional)

For U.S. educational institutions and non-profits, NASA’s CubeSat Launch Initiative (CSLI) provides opportunities to fly CubeSats as auxiliary payloads on upcoming missions, with selection cycles and programmatic requirements documented by NASA [28].

C. ISS deployment (CubeSat deployers via visiting vehicles)

Deployment from the ISS (or ISS visiting vehicles) has historically been a route for educational constellations and CubeSats that can accept the ISS orbit regime. Missions should evaluate inclination/altitude tradeoffs, lifetime, and regulatory constraints; integration providers publish deployer requirements and schedules (historical references include NanoRacks CubeSat deployer service documentation) [29].

D. Integrators, deployers, and orbital transfer vehicles (OTVs)

A key enabler for “mission-appropriate” orbits at low cost is the combination of rideshare with integrators (deployer providers) and OTVs. Providers such as Exolaunch publish multi-slot deployer systems and mission integration services (e.g., EXOpod sizing and slotting concepts) [30]. This architecture can materially improve orbital targeting without the cost of a dedicated launch.

E. Cost drivers and practical constraints

• Spectrum coordination and licensing: pursue IARU coordination early; launcher and deployer providers often require coordination evidence [13], [14], [31].
• Ground segment readiness: publish demodulation parameters and reference decoders; leverage SatNOGS and community networks for early commissioning [6], [23].
• Link budget realism: prefer modest data rates during commissioning; provide robust FEC and framing for low-SNR passes.
• Orbit selection: revisit objectives vs. orbit lifetime; very low orbits enable fast decay experiments but compress operations timelines [10].

VIII. Conclusion

The amateur and educational satellite ecosystem spans analog FM repeaters, linear SSB/CW transponders, and modern digital telemetry and packet payloads. Operational practice is strongly community-driven: live status reporting and transmitter databases reduce uncertainty for both operators and mission teams. Educational missions increasingly pair accessible RF payloads with meaningful sensors (thermal, power, attitude, radiation/environmental, GPS, and science instruments), and leverage open infrastructure (SatNOGS) and open flight software platforms (OpenSatKit/cFS) to reduce non-recurring engineering cost. On the launch side, commercial rideshare and targeted institutional programs (e.g., CSLI) provide viable low-cost access to orbit, especially when combined with standard deployers and OTVs.