Available Ham Satellites 2020 AMSAT-SA Symposium, August 22, 2020 Current and Near Future Amateur Radio Satellites Burns Fisher, WB1FJ, [email protected] Abstract This is a golden age of ham radio satellites! The first, Oscar-1, was launched in 1961. Saudisat SO-50 was launched at the end of 2002. That means that the first 50 satellites with OSCAR numbers took 41 years to launch. QO-100 was launched in 2018, so the next 50 took only 16 years, and that does not count satellites without Oscar numbers (notably by Chinese amateurs). Not all numbered Oscars are communications satellites, and not all are still operating, but regardless, there are probably more operating satellites available to radio amateurs now than ever before. The intent of this paper is to give you an idea of what satellites are available, although it will concentrate on the AMSAT (-NA) Fox FM satellites, the future linear satellite Fox-1E, and our LTM-1 linear transponder package used in HuskySat-1. It will include details about their amateur radio communication packages, their current status, and some information about their on-board experiments. It will also discuss the future AMSAT Golf series of satellites as well as a brief list of some of the other amateur communication satellites that are currently operational. Launch Changes Amateur radio satellites have always been launched as secondary payloads—meaning that we “piggybacked” on the launch of another satellite, or perhaps as “ballast” on a new rocket launch test. For most of their history, these birds were built by amateurs to fit a specific place on a specific launcher and with a specific main payload. More recently, “cubesats” have become an industry standard design for piggyback spacecraft. A “1U” cubesat is roughly 10cm on each side, and can weigh up to about 1kg (a “3U” cubesat is 10cm x 10cm x 30cm). They have the advantage that a builder does not have to design for a specific launcher or payload, and the launch provider can design with a simple standardized deployer in mind. However, the size, mass, and electrical power available (due to the size) require new thinking. And while this standardized design has made many more launch opportunities available, that also means that many universities and other institutions are also building satellites that amateur radio satellites must compete with for launch slots. Not surprisingly, launch providers have also become more adept at monetizing these launch slots by charging in the vicinity of $100K USD for a 1U cubesat launch to low earth orbit. This is inexpensive as launches go, but very expensive for non-profit organizations like AMSAT. The Fox Satellites The Fox satellites were designed as a follow-on to the highly successful and much loved “Echo”, AO-51. The Foxes were intended to help us learn how to build cubesats, and also to use a new launch financing model: Flying university experiments. Available Ham Satellites 2020 AMSAT-SA Symposium, August 22, 2020 The financing model works like this: We partner with a university who wants to fly an experiment, but is not especially interested in working out the radio and the telemetry part. We provide them up space for up to 4 boards, and they get a grant to include a launch. Many of our Fox satellites include variants of Vanderbilt University’s radiation effects experiment, and all contain an experiment proposed by Penn State University at Erie for using MEMS gyros on a spacecraft. The Fox satellites are all 1U cubesats that contain 9 circuit boards, of which 4 are designated for experiments. The 5 remaining boards are the receiver, transmitter, battery, power, and computer (IHU) boards. The first 4 Foxes are U/v FM repeaters with about 600mW of output power. They Figure 1: A Cubesat (Fox-1B, AO-91) all require a 67Hz tone to activate the transmitter. Telemetry is sent on the same channel with the voice downlink as 200bps “data under voice” and can be decoded with the free and open source program FoxTelem. All the FM Foxes also have a “carrier operated repeater” mode which will allow the radio payload to operate even if the IHU fails (although this failure has not happened on any Fox so far). Fox-1e was built with “leftover” Fox parts and a few newly designed boards that make it an exception to much of this, although FoxTelem was also redesigned to decode its telemetry. All the Fox satellites are powered by solar panels on all 6 faces and NiCad batteries (old tech but well understood, safe, and easy to get approved by the launch provider). They are stabilized by a bar magnet which aligns with the earth’s magnetic field (and thus flips over twice per orbit!) Here are some details on the Fox satellites: Fox-1A, AO-85 Fox-1A was the first Fox satellite launched. It was orbited by an Atlas Centaur rocket from Vandenberg Air Force Base in California, USA on 8 October 2015 into a 504x796 km orbit at 64.8 degrees inclination. Figure 2 shows this launch with a red arrow pointing to where the satellite was carried (right next to the Centaur engines!) It contains a 2-board Vanderbilt University experiment. It required a bit more uplink power than expected. We believe this was because of a last-minute antenna failure that was repaired in such a way that its impedance was likely thrown off. (We redesigned the antenna for future Foxes). Amateurs around the world used AO-85 for 4 years, but unfortunately the batteries failed (shorted) in 2019, likely due to the unexpectedly high temperatures that the satellite encountered during periods of full sunlight. It is Figure 2: Launch of Fox-1A on Atlas-Centaur Available Ham Satellites 2020 AMSAT-SA Symposium, August 22, 2020 possible the batteries will open sometime in the future and the satellite will operate in sun, so it is worth an occasional try. Fox-1B, AO-91, aka RadFxSat RadFxSat was launched on 18 November 2017 on a Delta 2 from Vanderberg into a sun- synchronous orbit of about 461 x 824 km and an inclination of 97.7 degrees. Its downlink frequency is 145.960MHz and the uplink is 435.250. It has it has all 4 slots filled with Vanderbilt experiments, hence the name Rad Fx (Radiation Effects and Fox). AO-91 continues to work well, providing repeater services to amateurs around the world, and (along with the experiment on AO-85) producing a number of academic papers as well as contributing to a PhD. Fox-1D, AO-92 Fox-1D was launched on 12 January 2018 on a PSLV rocket from the Satish Dhawan Space Center in India. It contains several different experiments: University of Iowa’s HERCI, Virginia Tech’s VGA camera, and AMSAT’s L-band downshifter. Its normal uplink frequency is 435.350 MHz, but it can be commanded to switch to an L-band uplink frequency of 1267.350 via the downshifter. It is currently operational, with commands sent occasionally to take pictures of the earth, and weekly to shift (for a max of 24 hours) to L-band uplink. We are seeing some battery degradation such that in eclipse the voltage sometimes drops below the conservative threshold that we set, and the satellite shifts into “safe mode”. Safe mode turns off the camera, the L-band downshifter, and the repeater to reduce power use. When it comes back into the sun and the voltages climbs back up to nominal, the satellite shifts out of safe mode (although the camera and the downshifter do not come back on without a ground command). Watch for passes that occur in daylight for the best results. Figure 3 shows an image from the Virginia Tech camera taken near Cape Cod Massachusetts, USA, downlinked line-by-line to multiple stations, and stitched back together at the AMSAT server. The blurry dot on the left side is actually one of the satellite antennas that is partly in front of the camera lens. You can see that this camera has better resolution than typical amateur slow-scan TV, Figure 3: Virginia Tech Cam Image from AO-92 although not as good as the newer Amateur TV. Unfortunately, licening requirements imply that we only can take pictures in parts of the northern hemisphere. Available Ham Satellites 2020 AMSAT-SA Symposium, August 22, 2020 Fox-1Cliff, AO-95 This satellite was named as a tribute to Cliff Buttschardt, K7RR (SK), a supporter and contributor to AMSAT and to the cubesat spec. It was launched from Vandenberg on a SpaceX Falcon 9 into a 560x582km 97.8 degree orbit. Its downlink frequency is 145.920. It did carry a Vanderbilt experiment, a camera, and an L-band downshifter. Unfortunately, its receiver failed sometime between its last ground test and its power on in orbit. We have been unable to command it out of its initial planned safe mode and thus it continues to send telemetry and the safe mode voice ID, but cannot be used as a repeater; nor can the camera be turned on. The failure reason is not known, although we can make some guesses. Most telemetry seems nominal, including an indication that the receive antenna is deployed. The only clue we have is that the telemetry for the received signal strength (RSSI) is very low, implying it is not even receiving noise. We have tried VERY strong uplink signals to no avail, another indication that the issue is not likely to be the antenna. There are a few possible receiver failure modes as well as the possibility of internal coax failure.