AMSAT Engineering · Project Update
Satellite Project Status
From a growing fleet of Fox-Plus transponders in low Earth orbit to GOLF’s drive back toward HEO, here is where AMSAT’s volunteer-built satellites stand.
Updated August 2026AMSAT’s engineering volunteers are advancing two complementary satellite programs. Fox-Plus will rebuild and sustain an easy-to-work fleet of 1U CubeSats in low Earth orbit, while GOLF (Greater Orbit, Larger Footprint) develops the technologies needed to carry amateur radio back toward high Earth orbit. This summary reflects the development briefing presented by the engineering team at the 2026 New England HamXposition.
Program One · Low Earth Orbit
Fox-Plus: The Next LEO Fleet
Fox-Plus A on track for completion in 2026Fox-Plus updates the proven Fox-1 design behind the five 1U CubeSats AMSAT constructed and operated beginning in 2015, an engineering lineage that also supplied RF hardware and support for university partner spacecraft including the University of Washington’s HuskySat-1 and the University of Maine’s MESAT1.
The first two Fox-Plus spacecraft pair a commercial ISISpace 1U bus with AMSAT’s flight-proven Linear Transponder Module (LTM), putting a V/u linear transponder on orbit for SSB and CW operation. Follow-on satellites will carry a four-uplink-channel PACSAT digital store-and-forward payload, and commercial launches are planned for the series.
On the bench, Project Manager Mike Moore, K4MVM, has the initial Fox-Plus test bed up and running, integrating the ISISpace battery pack and deployable antenna unit with AMSAT’s Linear Transponder Module, Power Signal Adapter, and mechanical adapter.
The goal is a fleet. Fox-Plus is AMSAT’s “Easy Sat” strategy: make instead of buy. Building these 1U spacecraft repeatably lets AMSAT keep multiple accessible transponders on orbit, so newcomers and portable operators reliably have satellites to work.
Program Two · Toward High Earth Orbit
GOLF: Greater Orbit, Larger Footprint
GOLF-TEE in subsystem development and flat-sat testingGOLF is AMSAT’s road back to wide-footprint, long-pass operating, ultimately from high Earth orbit. The first mission, GOLF-TEE (Technology Exploration Environment), is a 3U CubeSat that will prove the key technologies a future HEO spacecraft demands: radiation-tolerant computing, active three-axis attitude control, deployable solar power, and a multi-band software-defined transponder with a 10 GHz microwave downlink. Read an introduction to the GOLF program.
Software-Defined Transponder
A multi-band SDR provides multi-frequency transponder, beacon, and GPS position and timing modes. Uplinks can operate on the V, U, L, S, or C bands, with a 10 GHz X-band downlink through a solid-state power amplifier and quad-patch antenna for high-speed telemetry or multi-channel FDMA.
Radiation-Tolerant Computer
The RT-IHU/DCT is GOLF’s primary command and data handling computer: redundant COTS processors with autonomous failover for continuous operation, plus a frequency-agile telemetry and command transceiver supporting multiple modulation types, with higher downlink rates to come.
Legacy Linear Transponder Module
The flight-proven LTM card set (LIHU, ICR, and RX/TX boards) carries Fox heritage forward, providing the V/u linear transponder, command reception, telemetry downlink, and command and data handling.
Attitude Determination & Control
A CubeSpace 3U CubeADCS core stack with reaction wheels and magnetorquers, supported by sun and Earth sensors and magnetometers, delivers the active pointing that deployable solar arrays and directional microwave antennas require.
Electrical Power Subsystem
Deployable and fixed solar panels feed MPPT converters onto a 10–19 V bus with regulated 12 V, 5 V, and 3.3 V rails, dual switched battery packs, over-voltage protection, and a supervisor processor on the CAN bus. With all five +Y strings sun-pointed, the arrays can generate up to 35.8 W.
Radiation Science Experiment
In partnership with Vanderbilt University, VUC and LEPF experiment boards will investigate single-event upsets in commercial 16 nm FinFET SRAM, with data returned by telemetry to Vanderbilt for analysis.
GOLF-TEE communications design
- LT transponder: V/u
- SDR transponder: */X (* = V, U, L, S, or C)
- X-band: high-speed TLM or multi-channel FDMA
- UHF: telemetry & experiment data
- GPS: L1/L2 receive
Hardware on the Bench
Linear Transponder Module flat-sats and a full longitudinal-and-transverse stack test bed are running at engineering team members’ stations. A full-scale 3U “metal model” of the GOLF-TEE structure has been assembled with its subsystem boards, and the spacecraft SDR has evolved from a USRP E310 flat-sat prototype into AMSAT’s own GOLF-TEE SDR board. On the ground, AMSAT’s FoxTelem software already includes GOLF-TEE telemetry support.
Coming in 2026: SDR Gen 2
Ray Roberge, WA1CYB, is developing SDR Gen 2, a versatile GNU Radio-based transverter built to fly on both Fox-Plus and GOLF missions: continuous 144 MHz–6 GHz coverage; direct VHF, UHF, 900 MHz, L-, S-, and C-band operation; up-conversion for “five and dime” microwave capability; every mode from CW and SSB to FT8, NBFM, SSTV, and ATV; and a minimum 1 Msps downlink data rate.
The People
Built by Volunteers
Every board, bracket, and line of flight software described above is the work of AMSAT volunteers. Among the many hands on these projects:
- Jerry Buxton N0JYAMSAT Vice President – Engineering
- Mike Moore K4MVMFox-Plus Project Manager
- Eric Skoog K1TVVGOLF System Engineer
- Burns Fisher WB1FJAMSAT Software Lead
- Kip Moravec AE5IBElectrical Power Subsystem
- Ray Roberge WA1CYBSDR Gen 2 Development
…plus dozens more volunteers across AMSAT Engineering, Operations, and the ground station community. Want to lend your skills? Volunteer for AMSAT.
Keep Amateur Radio in Space
AMSAT’s satellites are designed, built, and tested by volunteers and funded by members and donors. Your membership and contributions directly support Fox-Plus construction, GOLF development, and the launches ahead. You can also support GOLF and Fox-Plus by joining the 2026 AMSAT President’s Club.