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OSCAR I and Amateur Radio Satellites: Celebrating 50 Years

05/11/2011

1961. It was the middle of the Cold War. John F. Kennedy is inaugurated as the 35th President of the United States. The Bay of Pigs invasion fails in Cuba. The Beatles perform for the first time at the Cavern Club in Liverpool. Freedom Riders are arrested in Jackson, Mississippi for “disturbing the peace” after disembarking from their bus. Construction of the Berlin Wall begins. Roger Maris of the New York Yankees hits his 61st home run in the last game of the season, beating the 34 year old record held by Babe Ruth. Barbie gets a boyfriend when Mattel introduces the Ken doll.

Just four years earlier, the Soviet Union had launched Sputnik I, the first human-made object to orbit the Earth, ushering in the Space Age. For the next 30 years, the Cold War rivalry between the US and the former Soviet Union focused on attaining firsts in space exploration. These were seen as necessary for national security and symbolic of technological and ideological superiority. The “space race” involved pioneering efforts to launch artificial satellites, sub-orbital and orbital human spaceflight around the Earth, as well as piloted voyages to the Moon.

1961. Mercury-Redstone 2 launches into space carrying Ham the Chimp. Soviet cosmonaut Yuri Gagarin becomes the first human in space. Alan Shepard becomes the first American in space aboard Mercury-Redstone 3. Gus Grissom, piloting the Mercury-Redstone 4 capsule Liberty Bell 7, becomes the second American to go into space. OSCAR I -- Orbiting Satellite Carrying Amateur Radio -- the very first Amateur Radio satellite, is launched into space.

Barely four months after the successful launch of Sputnik I, the United States launches the unmanned Explorer I on January 31, 1958. At about that same time, a group of hams on the West Coast -- Lance Ginner, K6GSJ; Chuck Smallhouse, W6MGZ; Ed Beck, K6ZX; Al Diem; Chuck Townes, K6LFH (SK), and Nick Marshall, W6OLO (SK) -- begin toying with the idea of launching an Amateur Radio satellite into orbit and organized themselves into Project OSCAR. After a series of high level exchanges among Project OSCAR members, the ARRL and the US Air Force, a launch opportunity on a Thor DM-21 Agena-B rocket from Vandenberg Air Force Base in California was secured for the very first Amateur Radio satellite: OSCAR I. It was successfully launched into a low Earth orbit on the morning of December 12, 1961 -- four years after the launch of Sputnik I. The satellite was also the world’s first non-government bird.

In 1961, more than 570 amateurs in 28 countries forwarded observations to the Project OSCAR data reduction center. Unfortunately, OSCAR I lasted only 22 days in orbit before its batteries gave out. Transmitting “HI HI” in Morse code on 145 MHz, OSCAR I ran on only 140 mW on battery power. The word “HI” was chosen over any particular call sign, since it was -- and still is -- is internationally recognized as a friendly greeting among radio amateurs.

The satellite was built, quite literally, in the basements and garages of the Project OSCAR team. It was the first satellite to be ejected as a secondary payload from a primary launch vehicle and then enter a separate orbit. This was accomplished using a very high technology and thermally balanced ejection system: a $1.15 spring from Sears. The total out-of-pocket cost (not including material donations) of OSCAR I: only $68.

OSCAR I was a 10 pound, 12”×12” package constructed mostly of magnesium, used for both its strength and because of weight requirements. The satellite was located near the tail-end of the rocket, near the engines. The satellite was tested and designed to handle nearly 50 Gs of force, the type of shock that might be encountered during launch and separation phases. The final version of OSCAR was gold-plated and had black metallic strips across its case to regulate its internal temperature. Explosive squibs and compression springs helped propel OSCAR I away from the rocket. Spring switches on the satellite released the antenna and applied power to the transmitter/keying circuits.

A keyer and timer were used to generate the “HI.” The speed at which “HI” was sent was based upon the internal temperature of the satellite. Two thermistors located within the craft controlled the timer, and it’s the temperature variations the thermistors sensed that determined the CW speed. Three 18 V batteries were placed in parallel to power the transmitter, timer and keyer. The entire unit was filled with a foam-like material to keep the internal boards immobile. Since there was no solar-cell charging system available at the time, the original designed/expected operating time for the batteries was approximately 28 days.

Fast forward 50 years to 2011. An estimated 2 billion people watch the wedding of Prince William, Duke of Cambridge and Catherine Middleton at Westminster Abbey in London. Osama bin Laden, the founder and leader of the militant Islamist group Al-Qaeda, is killed during an American military operation in Pakistan. Southern Sudan holds a referendum on independence. Egyptian President Hosni Mubarak resigns after widespread protests calling for his resignation. A 9.1-magnitude earthquake and subsequent tsunami hit the east of Japan, killing more than 14,000 and leaving another 11,000 missing. Amateur Radio celebrates the 50th anniversary of the OSCAR I launch.

Fifty years is a long time -- and an important milestone, thought ARRL Lab Test Engineer Bob Allison, WB1GCM. And then he had a lightbulb moment: Why not take the back-up OSCAR I on display at ARRL Headquarters and make it work again? So W1AW Station Manager Joe Carcia, NJ1Q and Allison began tinkering with the satellite, one of three made by Project OSCAR. One of the satellites went up into space in 1961, one is on display at the Smithsonian Air and Space Museum in Washington, DC and the other was until recently sitting in a display case on the first floor of the HQ building in Newington.

“We really wanted to make this work again,” Allison said. “So we looked in the February 1962 issue of QST that was dedicated to OSCAR I, the first-ever Amateur Radio satellite to go into orbit. But the schematic we published didn’t quite mesh up with what we were seeing when we opened up the satellite we had here at Headquarters.” [Editor’s note: You must be an ARRL Member to access the link]

According to Carcia and Allison, this could be that back in the days of the Cold War and the space race, the US military did not want the correct schematic falling into improper hands. “I tried for days, tracing components on the board and it just wasn’t working,” Carcia said. “So I called up Lance Ginner, K6GSJ, one of the original Project OSCAR people. He kind of laughed and said that he didn’t think they would do that, but you never know.”

After much trial and error, Carcia finally got OSCAR I to transmit a signal on 145 MHz, just as the original satellite did. Since specific technical literature on the satellite was unavailable, information taken from 1962 QST and CQ articles assisted in the reconstruction of the transmitter in the ARRL unit. Much care was given to salvage the original components, although time had taken its toll on most of the circuitry. As such, although the transmitter functions, the actual keying of the transmitter is performed using a PIC beacon keyer. Power is supplied using a standard wall-cube providing 12 V dc.

In honor of OSCAR I’s 50th anniversary, the rebuilt satellite will be on display at the ARRL EXPO area at the Dayton Hamvention, May 20-22 at Hara Arena in Trotwood, Ohio. “We have hooked OSCAR I up to a dummy load running very low power, and as you walk by, you will hear it transmit “HI HI,” just as it did 50 years ago,” Allison said. “Since the transmission does not identify, you won’t be able to pick it up on your handheld transceiver while at Hara. OSCAR I will be running as a Part 15 device.”

“OSCAR I opened to door to the world of Amateur Radio satellite communications,” Carcia explained. “Fifty years later, Amateur Radio operators continue to build and launch radio satellites that perform and function in ways the original designers could only imagine!”  -- Thanks to AMSAT for some information



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