Keeping Amateur Radio in Space - 21st Century Challenges and Opportunities for AMSAT

Daniel Schultz N8FGVn8fgv@amsat.org

The amateur radio in space program began on December 12, 1961, when members of Project OSCAR built and launched the OSCAR 1 satellite as a secondary payload on the US Air Force Discoverer 36 mission. This was the world's first satellite built with non-governmental funds and the first deployment of a secondary satellite from a launch vehicle. The political and bureaucratic effort to obtain approval for launch greatly exceeded the technical effort in building the satellite (1), but it created the precedent for launching secondary payloads and thus played a part in creating the small satellite industry that we know today. The political effort to secure launch approval was aided by several well-connected hams in the Pentagon, who convinced their superiors that the small amount of added risk to the primary mission in carrying a secondary satellite was worth accepting. It is good to have friends in high places who believe in your vision when you are trying to propose something so ridiculous as an “amateur satellite”

OSCAR 1 replica on display at the National Air and Space Museum Udvar-Hazy center

A long series of OSCAR satellites followed in the 1960's through the 1990's, culminating in the launch of the 600 kg AMSAT-OSCAR-40 with a live hypergolic propulsion system in November 2000. Many were launched at little or no cost to the amateurs who built them, but the success of these amateur satellites attracted the attention of government, universities and business. Soon a thriving enterprise of small satellite organizations sprang up and demand for secondary launches grew exponentially. Commercial launch providers learned that they could actually charge money for these formerly "free" launches. The road to space gradually closed for amateur organizations funded by member donations.

The German Phase 3E amateur satellite languished for well over a decade as efforts to find an affordable launch were fruitless. AMSAT's “Eagle” project, a proposed 100 kg high altitude satellite to replace some of OSCAR-40's functionality, never got close to finding a launch.

In the late 1990's AMSAT member Bob Twiggs of Stanford University proposed the first "CubeSat" standard in an effort to secure rapid and low cost launch opportunities for his students. His idea was to define a standard external form factor to allow interchangeable satellites to be launched in a sealed box that would protect the primary payload from harm if the enclosed CubeSat should disintegrate from launch vibrations on ascent to orbit. The standard “1U” CubeSat was ten centimeters (four inches) on a side, which made them even smaller than AMSAT's 25 centimeter (ten inch) “Microsats” that were first launched in the 1990's.

Soon every university on Earth was building their own CubeSat. Their students got to participate in a real satellite mission, and some of those students got to see their satellite launched into space before they graduated. The satellite was generally considered successful if the students delivered a working CubeSat to the launch authority, whether it functioned correctly on orbit was an incidental consideration. CubeSats proved to be popular with the aerospace industry which saw them as a way to increase the supply of young engineering talent that they could hire upon graduation. Space missions that might have carried an OSCAR satellite in earlier years were now full of CubeSat dispensers, and the amateur satellite program fell even more out of favor.

Things got even worse for AMSAT in the late 1990's when the US Congress passed legislation creating the International Traffic in Arms Regulations (ITAR), which classifies every little piece of spacecraft hardware as a dangerous munitions item that must not fall into the hands of an enemy nation. As a resultof ITAR, AMSAT was now an international munitions dealer! This program was administered by the US Department of State, a disfunctional bureaucracy that really doesn't understand the concept of satellites built by hobbyists. ITAR restricts not just the movement of actual space hardware, but every new idea or concept for any spacecraft mission is now restricted information that must not be communicated to any “non-US person”, even in informal settings like the hallways and lounges at the annual AMSAT Space Symposium.

ITAR has forced AMSAT-North America to disengage from other AMSAT organizations around the world, and destroyed the international cooperation that made complex projects possible. AMSAT-OSCAR-40 was a collaboration of AMSAT organizations from a dozen different countries in a 1990's pre-ITAR environment. Building this satellite would have been impossible under present day ITAR rules. In one recent year AMSAT spent more money on legal fees than it spent on satellites. In the past couple of years Congress has lightened up on some of the more onerous aspects of ITAR, but AMSAT is still bound by restrictions on dissemination of technical ideas and concepts, to the point where we must restrict membership in AMSAT's engineering team to US citizens only.

In 2007 NASA created the “Educational Launch of Nanosatellites” (ELaNa) program (2) to manifest free CubeSat launches for educational institutions on every US Government sponsored launch that has excess lift capacity. AMSAT's own Tony Monteiro, AA2TX (SK) played a key role in convincing NASA to open the program to non profit organizations like AMSAT.

A lot of AMSAT folks considered these four inch cubes to be much too small to enable any kind of “interesting” mission, but when that is all you have you can either sit back and complain about your badluck or you can get to work. AMSAT chose the latter path and started work on the FOX program in

2009, which led to the first launch of the FOX-1 CubeSat (now AMSAT-OSCAR-85) this past October 8, 2015 as a passenger on a US Government launch (3). Two more FOX satellites have completed testing and will soon be delivered to the government for launch, and additional satellites are on the way (4,5).

AMSAT FOX-1 satellite launched October 8, 2015

NASA's ELaNa program was not created for hams to launch communications satellites. In order to obtain a launch from NASA, our satellite must carry a scientific or technological payload that fulfills one of NASA's technical or educational objectives. AMSAT has partnered with Vanderbilt University to carry a small radiation effects experiment (“RadFX”) that will measure the degradation of modern semiconductor devices in the space environment, this engineering payload provided the technical hook that allowed the FOX satellite to obtain a government sponsored launch. The FOX satellite is often referred to by the RadFX name in NASA publications. The University of Iowa recently partnered with AMSAT on a scientific payload for Fox-1D (6). We continue to seek partnerships with science and technology organizations to place their small payloads on an AMSAT satellite in return for a NASA sponsored launch.

CubeSats have been getting larger in recent years, with 3U (10x10x30 cm) satellites now common, and a number of 6U (10x20x30 cm) missions in the planning stage. This relieves some of the constraints onperformance but it will still be challenging to fit the functionality of previous AMSAT satellites into a box that small.

New missions for AMSAT

The usual AMSAT suspects lined up in front of the Millennium Space Systems Aquila M8 Satellite

An opportunity has recently surfaced for AMSAT to place a hosted payload on an experimental geosynchronous satellite to be built for the US Air Force (7). Work is now underway to build a software defined radio transponder with 5.65 GHz uplink and 10.475 GHz downlink under tight deadline pressure. The digital transponder will support more simultaneous users than any HF band at any given time, and the use of SDR technology will allow new transponder functions to be created in code and installed onboard the satellite after it is in orbit. A geosynchronous satellite will remain in a fixed location in the sky and will be available 24 hours a day, enabling the practical use of an amateur satellite for public service and emergency communications for the first time ever.

AMSAT has partnered with Ragnarok Industries (8) to provide a similar communications system for their Lunar CubeQuest Challenge (CQC) entry for which they are competing for a launch slot on the first flight of the NASA Space Launch System in 2018. The mission will attempt to transmit data from lunar orbit in pursuit of several cash prizes that NASA is offering, and the satellite can be turned over for amateur radio use from lunar orbit when the primary mission is completed. It will use the same uplink and downlink bands as the geosynchronous satellite project.

AMSAT-DL and Virginia Tech recently announced a partnership in which the university will modify thePhase 3E satellite that has been in storage for well over a decade and launch that satellite directly into an elliptical Molniya orbit on a US Government launch (9). Because of the sensitive nature of the primary mission, details about this launch may not be forthcoming until the satellite is actually in orbit!

Ragnarok Industries design of a 6U CubeSat for lunar orbit in 2018

CubeSats in HEO?

Low Earth Orbit (LEO) missions offer very short pass durations and a limited number of users. Hams would like to have another High Earth Orbit (HEO) satellite like AO-10, AO-13, or AO-40. Ideally we would be able to launch a new satellite every few years to replenish the constellation as older satellites fail. A satellite in elliptical orbit would require effort by the users to track the moving satellite but it would also offer a wider variety of DX opportunities for hams who collect countries and grid squares.

Analysis of the orbital behavior of spent rocket bodies and other debris left in elliptical geosynchronoustransfer orbits shows that such orbits are sufficiently stable over a ten or twenty year mission lifetime (10). A CubeSat deployed from a geosynchronous launch would offer a long and stable life to serve the amateur radio community. Work continues to devise a method to use the lunar-solar perturbations of an elliptical orbit to insure eventual reentry at the end of the mission lifetime to satisfy regulations concerning orbital debris accumulation.

HEO is a very different environment from LEO, the engineering challenges are more like the problems of cislunar or interplanetary space. CubeSats that work well in LEO need to be redesigned for missions farther from Earth. Technology needed for a HEO satellite is similar to what is needed for lunar or interplanetary Cubesat missions, and the experience that we will gain in working with Ragnarok Industries on their lunar mission will fit nicely into this project.

Specifically, satellites in LEO are very close to the Earth, enabling easy communication with simple antennas. In LEO, infrared radiation from the warm Earth fills half of the sky, keeping the satellite warm and simplifying thermal design. The radiation environment is fairly benign, and there is a strong magnetic field to torque against for attitude control.

High Earth Orbit satellites are farther out from Earth, requiring directional antennas and higher transmitter power for effective communications. The thermal environment is much colder out in deep space, the satellite operates in a more difficult radiation environment, and the weak magnetic field requires more complex attitude control systems.

To close the communications link from a satellite thousands of kilometers from Earth requires more transmitter power and more antenna gain. Large solar arrays will be needed, and the satellite thermal design must be able to reject the waste heat from the transmitter power amplifier. This will require a solar array deployment mechanism and possibly a solar array gimbal drive mechanism and rotary slip joints. OSCAR-13 had much larger body mounted solar arrays and we could tolerate the loss of energy generation that was caused by having the satellite's spin axis pointing away from the Sun.

Electrical power is the single most precious commodity on a satellite, and the use of digital data links with forward error correction (FEC) allows us to trade off increased signal bandwidth for lower transmitter power. Digital regenerating transponders allow the uplink and downlink properties to be separately optimized, giving a performance advantage over conventional bent pipe analog transponders

Directional antennas need to be aimed at the users on Earth. Putting a high gain antenna on a 6U satellite that is only 10x20x30 centimeters is a challenge, we will need to go to microwave frequencies to get the required antenna gain in a small package. Keeping the solar arrays pointing at the Sun and theradio antennas pointing at the Earth will require three axis attitude control of the satellite, a capability that AMSAT has yet to demonstrate.

We want to develop an ongoing and sustainable program to allow launching a new satellite every few years to replace older satellites as they fail. To earn our rides to space we will need to carry compatible satellite instruments and payloads to make scientific measurements and technological demonstrations that will be relevant to NASA or other launch agencies. We continue to seek partnerships with scientistsand research organizations to identify such opportunities.

Can we squeeze the functionality of AO-13 into a 6U sized shoebox? Can we get it launched into HEO?Stay Tuned!

Ground Station Development

There is no commercially available plug-and-play ground station equipment for digital 5.65 GHz uplink and 10.475 GHz downlink operations. AMSAT recognizes that satellite operation on these bands will not become a mainstream activity for radio hams until there is a prepackaged ground station kit thatcan be ordered from Ham Radio Outlet for minimal cost. AMSAT also recognizes that hams will be reluctant to purchase equipment that may become obsolete if the satellite that supports it should fail. Forthis reason AMSAT plans to use this transponder scheme on as many high altitude satellites as possible to enable the ground station kit to deliver maximum value to its owner and to insure against obsolescence of the ground station investment if any one satellite should fail.

The vision is to design a prepackaged ground system engineered to sell for the lowest possible cost and to be no more difficult to set up than a digital satellite television receiver. A system with a one meter dish antenna would look very similar to the satellite TV receivers that are exempt from most home owners association restrictions.

A system designed solely for geosynchronous use would require no tracking mechanism, just aim it at the satellite and tighten the bolts. A system for use with elliptical orbit CubeSats would require computerized tracking with a small set of azimuth and elevation actuators. We need help from mechanical designers who can design a dish tracking system that can be reproduced for minimal cost.

The extensive use of digital modulation/demodulation, forward error correction, digital voice processing and data multiplexing are all software tasks that require specialized skills that are in short supply in the commercial world as well as the amateur radio world.

Satellite ground station equipment is not subject to ITAR restrictions, and AMSAT welcomes ideas and participation in the ground station development from all hams regardless of their citizenship (11, 12, 13,14, 15, 16).

References

(1) Keynote Speech, Lance Ginner, K6GSJ, 2011 AMSAT Space Symposium, San Jose, CAhttps://youtu.be/EWSCCZY1FgQ

(2) NASA Educational Launch of Nanosatelliteshttp://www.nasa.gov/mission_pages/smallsats/elana/index.html

(3) AMSAT News Service Bulletin ANS-284.01 - Fox-1A Launched at 0549 PDT on October 8, 2015http://amsat.org/pipermail/ans/2015/000876.html

(4) ANS-216 - RadFXSat/Fox-1B Launch Opportunityhttp://amsat.org/pipermail/ans/2015/000862.html

(5) ANS-052.02 - RadFxSat-2 (Fox-1E) Selected for Participation in NASA's CSLIhttp://amsat.org/pipermail/ans/2016/000897.html

(6) AMSAT and University of Iowa Partner on Scientific Payload for Fox-1Dhttp://www.amsat.org/?p=3844

(7) ANS-116.01 - AMSAT-NA Opportunity for Rideshare to Geostationary Orbithttp://amsat.org/pipermail/ans/2015/000843.html http://www.amsat.org/?p=4058

(8) Ragnarok Industries http://www.ragnarokindustries.com

(9) ANS-206 - AMSAT-NA, AMSAT-DL, and Virginia Tech Announce Potential Phase-3E Opportunityhttp://amsat.org/pipermail/ans/2015/000859.html

(10) CubeSats in HEO, a Challenging Mission for AMSAT, Daniel Schultz, N8FGV 2013 AMSAT Space Symposium, Houston, TXhttp://qsl.net/n8fgv/2013-AMSAT-paper.pdf

(11) All documentation and software for the ground station project can be found athttps://github.com/phase4ground

(12) The mailing list is phase4@amsat.org and the archives can be found at http://www.amsat.org/mailman/listinfo/phase4

(13) Weekly engineering report for Phase 4 radio project - January 29, 2016 http://amsat.org/pipermail/ans/2016/000894.html video at https://youtu.be/c0CMv0pJHgY

(14) Weekly engineering report for Phase 4 radio project - February 14, 2016http://www.amsat.org/?p=4988

(15) AMSAT Ground Terminal Development Expands to Texashttp://www.amsat.org/?p=4822

(16) Videos of the weekly engineering reports can be found athttps://www.youtube.com/user/abraxas3d/

5.65 GHz uplink and 10.475 GHz downlink digital transponder for the geosynchronous satellite.