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Amateur Satellite Pioneer Tom Clark, K3IO, SK

Discussion in 'Satellite and Space Communications' started by K1LKP, Sep 30, 2021.

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  1. K1LKP

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  2. IW2BSF

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    RIP !


    ARISS I Chair Frank Bauer: Mourning the Passing of Dr. Thomas A. Clark, K3IO, formally W3IWI (SK)


    It is with great sadness that ARISS-International recognizes the passing of a dear friend, Dr. Tom Clark, K3IO. Tom passed away on September 28, 2021 in Columbia, Maryland.

    Tom Clark is recognized as a pioneer, trailblazer and a legend who led innovations and initiatives that have been transformative and significantly impactful to humanity. These include his pioneering work in radio astronomy, particularly VLBI (Very Long Baseline Interferometry), his contributions in the development of small satellite architectures that transformed the satellite industry, and his pivotal contributions in digital communications techniques and precise time measurement. These efforts span his professional career at NASA as a scientist and his parallel, avocational career as a leader, architect, and chief technologist at AMSAT-NA (President, Board Member, President Emeritus).

    For ARISS, Dr. Clark co-led the startup of our human spaceflight amateur radio initiatives and helped us develop systems on the Shuttle and ISS that actively engaged students and the ham radio community. As president of AMSAT, he worked with senior leaders at the ARRL and NASA to set up agreements on Owen Garriott, W5LFL’s inaugural flight of amateur radio on the Space Shuttle (STS-9). His technical and financial support to SAREX (Shuttle) and ARISS (ISS) have been vital in moving these programs to new heights. When Astronaut Ron Parise, WA4SIR planned to fly on a March 1986 mission prior to Challenger, Tom led a team of four of us, including Bob Bruninga, WB4APR, to develop protocols and software for rapid message exchange via a packet “Robot.” In Bob, WB4APR’s words, these “discussions helped firm up ideas on how APRS could be used not only as positioning tool, but also as a communication capability allowing rapid status and message reporting. Thus, allowing lots of people to rapidly make exchanges during a brief satellite pass.” The packet robot was used heavily in our SAREX (Shuttle) program, starting with Ron's STS-35 flight, after the Challenger accident. APRS remains a key staple in our ARISS on-board systems. Prior to his passing, Tom was also providing technical guidance in the development of lunar radio architectures we were proposing for Gateway and other opportunities around or on the Moon.
    Tom’s NASA career centered upon his pioneering work to develop, deploy and evolve several generations of VLBI systems. These systems substantially improved over time due to Tom’s passion of introducing with leading-edge (or, in Tom’s terminology, bleeding edge) technologies in radio, timing and data accumulation. VLBI is an astrophysics technique that combines observed stellar radio signals from space using several radio telescopes over a large baseline (the bigger the better). This creates a bigger effective radio telescope aperture, and thus, more spectacular results. VLBI is used to better understand the spinning motion of the Earth, the dynamics of the Earth’s crust, including global plate tectonics, to provide a more accurate definition of our celestial reference frame and to more accurately measure Universal Time. Tom linked together a global network of about 30 VLBI stations to make this happen. He continued to improve the timing precision of VLBI in the mid-1990’s through employment of the newly operational of GPS system. In fact, his “Totally Accurate Clock,” a playful use of his initials, has been found in VLBI stations and many other networks (and ham stations) around the globe.

    For AMSAT, in 1981, Tom brought computer orbit prediction to the masses by publishing a reduced set of code originally on mainframe computers that could be programmed into the nascent personal computers of the day (e.g. Sinclair, Atari, Apple, TI). This innovation proved key to tracking the Shuttle during W5LFL’s flight and continues to serve hams today. He energized a demoralized international team after the spectacular loss of an Ariane-V rocket that also destroyed the Phase 3A spacecraft. His leadership propped up the team and led to the successful launch of AO-10 and 13. Clark was one of the architects of the Microsat, a set of 4 cubed microsatellites first launched in 1990 which paved the way for the CubeSat revolution. As an early founder and leader of TAPR, the Tucson Amateur Packet Radio organization, Tom helped move packet radio from an idea to a key operational capability in amateur radio. When talking publicly, Tom would frequently remind the audience that the word “amateur” in amateur radio should not be a disparaging word, because the Wright Brothers innovated as amateur aircraft builders, just like radio amateurs have innovated radio and satellite technology for the betterment of society.


    Those that knew Tom personally, knows he generously provided advice, shared knowledge or helped you move a project forward that he believed in. As GPS was closing in on full operations in mid-1995, Tom and I worked on several GPS initiatives, the most notable was the use of GPS above the constellation. Tom facilitated the manifest of a GPS experiment on AO-40 that I led as a NASA Principal Investigator. This experiment has instrumental in rewriting the books on how GPS is used in space. The day before Tom’s passing, NASA released a video on the benefits of these capabilities

    Tom’s interests outside of the above, included photography, music, and cars. I leave you with a picture (below) of his final pride and joy: a Porsche Cayman which he affectionately called Ol’ Yallar II.

    Thank you, Tom, for all you have done for ARISS, AMSAT, NASA and humanity. We wish you Godspeed. Have a wonderful journey amongst the stars!

    info by : Frank H. Bauer, KA3HDO


    73 de IW2BSF - Rudy

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