The University of Surrey's UoSATs
Have Served Many Purposes

1990s hamsats:     Microsats     UoSATs     Radiosputniks     Mini-Sputnik     Fuji     Badr     KITsat


By the end of the 1980s, University of Surrey space enthusiasts had a complex new satellite, UoSAT-C, ready to go to space. In fact, it was scheduled for launch in 1988 on a U.S. rocket, but the flight was postponed. The UoSAT team wasn't able to locate a ride to space for the heavy UoSAT-C, but they did obtain a launch for a pair of lighter satellites on the Ariane ASAP test.

Those were UoSAT-OSCARs 14 and 15 microsatellites launched in 1990.
   [See also UoSAT-OSCAR-22 launched in 1991]

Due to ASAP weight limits, the functions of UoSAT-C had to be split between two lighter replacement satellites-UoSAT-D and UoSAT-E.

Fortunately, UoSAT-C had been loaded with modules which could be pulled apart quickly to take advantage of the short-notice Ariane opportunity. Many mechanical and electrical parts of UoSAT-C were taken apart and reassembled. The UoSAT-C framework was shelved.

UoSAT-D and UoSAT-E were matching frameworks outfitted with identical housekeeping computer systems, but otherwise housing different electronic payloads. They would be low-orbit pacsats with message handling. They would study space radiation and its effects on semiconductors, develop a low-cost computerized spacecraft attitude control for precise Earth pointing, and photograph Earth with a low-cost charge-coupled device (CCD) television camera.

ASAP attachments. UoSAT-D and UoSAT-E were attached to the ASAP and launched January 22, 1990, alongside the four AMSAT microsats.

UoSAT-D was renamed UoSAT-OSCAR-14 (UO-14). It also has been called UoSAT-3.

UoSAT-E was renamed UoSAT-OSCAR-15 (UO-15). It also has been called UoSAT-4.

Surrey hams successfully commanded UO-14 and UO-15 on during their first day in space. Later that day, each spacecraft's computer software was sent up by radio to the satellites. Nominal telemetry was received from both hamsats.

Bad news. Unfortunately, news turned bad 25 hours later when no UO-15 signals were received at Surrey.

Operators repeatedly transmitted commands to activate its redundant systems, with no luck. They tried for months to hear something, but no signals have been received since then from UO-15.

Stanford University had helped Surrey back in 1982, transmitting a strong signal to UO-9 to overcome blockage of that satellite's command receiver. Stanford hams tried again in 1990 to come to the rescue, using the same 150-ft. antenna with sophisticated digital signal processing equipment to look for an extremely weak signal from UO-15 oscillators. The big dish was able to hear UO-14 oscillators, but nothing from UO-15.

Dead in orbit. Attempts to restart UO-15 were abandoned. U.S. government radar continues to track the satellite, orbiting a mile or so higher than UO-14, amidst the pack of microsats launched January 22, 1990. UO-15 is simply dead in orbit.

The loss of UO-15 was mitigated by the good news from UO-14 which worked well. The tragedy spurred UoSAT to build a new small satellite, UoSAT-F, which was launched in 1991.

Meanwhile, UO-14 was working well in orbit handling lots of electronic-mail messages.

UO-14 has three computers for housekeeping and packet radio, including a 16-bit microprocessor with 4.5 megabytes of RAM. Four megabytes are used for bbs message storage.

The satellite's digital transponder receives at 145 MHz and transmits at 435 MHz. Ten watts of transmitter power make the satellite usable by small portable ground stations. Telemetry data packets are beaconed near 435 MHz.

Earth-pointing satellite. UO-14 is an Earth-pointing satellite with a gravity-gradient boom and computer-controlled magnetorquing, an ideal system for small satellites in low-Earth orbit because it has no continuously-moving parts and expends no fuel.

To calculate its attitude, UO-14 carries a flux-gate magnetometer measuring Earth's geomagnetic field in the satellite's three axes.

Electricity is generated by gallium-arsenide solar arrays feeding nickel-cadmium rechargeable batteries. The satellite rotates slowly, distributing the Sun's light and heat evenly across the satellite.

Gateways. Pacsats regularly relay messages around the globe to terrestrial packet networks in many regions. A gateway is a satellite ground station acting as a bridge between a pacsat and a terrestrial network. Automated gateways upload and download traffic without human operators.

In 1991, radio amateurs in Alaska and California created a gateway offering same-day delivery of dozens of messages to Alaska from the Lower 48 states. That success brought gateways to every continent. Today, scores of gateways cover North and South America, the Caribbean, Europe, the Middle East, South Africa, Oceania, Asia and even Baffin Island above the Arctic Circle. They deliver messages and responses within 24 hours. Such fast action is important in health-and-welfare traffic during emergencies and natural disasters.

In 1992, the first medical image transmitted via hamsat showed a fractured hip repaired with a compression hip screw. The hip had been pictured by a portable fluoroscopy X-ray displaying real-time images on a TV monitor for a physician during surgery. The image was stored on computer disk and transmitted to UO-14. The satellite kept it in memory for a few days, then sent it back to Earth, proving hamsats can help remote clinics get assessments from specialists.

VITA. Some of the construction costs of UO-14 had been paid by an American organization known as Volunteers In Technical Assistance. The non-profit organization had a large library of data on farming, windmills, stoves, ovens and other useful non-military subjects which it wanted to send to development workers in remote areas via UO-14's store-and-forward mailbox.

For a time, radio amateurs and VITA shared UO-14's transmitter, computer and 400-message memory. To accommodate both amateur and non-amateur users, the satellite switched back and forth between amateur and non-amateur frequencies.

When UO-14 transmitted on its non-amateur frequency, it was sending technical information to areas of the developing world poorly served by existing data communications. Such traffic was considered inappropriate for amateur channels. When the transmitter switches occurred, amateurs lost reception from their satellite for periods from a quarter-second to five seconds.

Traffic congestion. UO-14's uplink became congested with users. When 200 stations began using the satellite regularly, the satellite's 400 message limit was reached frequently. Amateur stations were limiting access for non-amateur VITA stations. After the British hamsat UO-22 was launched in 1991, Surrey decided to change UO-14's mission.

Amateur radio service was dropped. UO-14 stopped transmitting on its amateur frequency. Ham operations were moved to the new UO-22.
[UO-14 history]     [UO-14 status]

UO-14's electronic mailbox linked VITA with inexpensive, portable ground stations built around a computer, radio, battery and antenna. A ground station fits in a suitcase and works where no power lines exist. The pacsat is low enough for small ground stations to use simple whip antennas, made from coat hangers if necessary, to hear the satellite.

Ten magazine articles. UO-14's bbs memory holds four million characters of information. When the satellite is overhead, a ground station can send up a message at 500 characters per second. During the few minutes the satellite is overhead, a ground station might send up 200,000 characters of information-equivalent to ten magazine articles.

Even if mail were picked up immediately by a recipient the next time the satellite passed over his head, it might be stored in the satellite from a few seconds up to twelve hours. Mail can stay in the satellite for days, of course, awaiting radio commands from an addressee.

A busy operator on the ground can put his satellite station on autopilot. He programs his computer to determine when the satellite will be overhead. Most pacsats pass over the North and South Poles every hour and a half and over any one point on the surface four times a day. One is overhead for only a dozen minutes or so.

At the appointed hour, the ground-station computer would fire up its radio and send up a signal asking the satellite if any messages were on hand. If messages for that ground station were stored in the satellite, the satellite's computer would order them sent down.

The computer on the ground then could store them for future reading and turn off its radio as the satellite passed out of sight over the horizon.

Cheap 'n easy. A pacsat like UO-14 and others makes it cheap and easy to send messages, data and images in or out of developing regions. Scores of portable ground stations already are linking underdeveloped countries to medical, weather, agriculture and engineering databanks.

Volunteers in Africa, Asia and South America use portable ground stations to ask for technical assistance. Travelers in the most rugged terrain receive data. Relief workers communicate directly with emergency teams at natural disaster sites.

How UO-14 came back to ham radio. After UO-14 was launched in January 1990, it was operated for 18 months as an amateur message store-and-forward satellite. Its additional non-amateur payload, known as Healthsat-1, waited to start its work.

After UO-22 was launched in July 1991, the amateur payload was turned off and Healthsat-1 was switched on to serve the Volunteers In Technical Assistance (VITA), which used it for eight years to send medical messages to Africa.

When the computer aboard UO-14 no longer was able to handle messages, UO-14 was re-assigned in March 2000 as a single-channel FM voice repeater for Amateur Radio.

Its uplink is 145.975, and the downlink is 435.070.

1991: UoSAT-OSCAR-22

For the first time ever, on July 17, 1991, thirteen OSCARs were active in orbit at one time. They were AO-10, UO-11, AO-13, UO-14, AO-16, DO-17, WO-18, LU-19, FO-20, AO-21/RS-14, the RS-10/RS-11 combo, the RS-12/RS-13 combo and the brand-new UO-22.

British amateur radio satellite UoSat-1 Hams at the University of Surrey had designed and built yet another small satellite, UoSAT-F, which was launched that July 17 on a European Ariane rocket. In polar orbit, 480 miles above Earth, UoSAT-F was renamed UoSAT-OSCAR-22. It also was known as UoSAT-5.
[UO-22 history]     [UO-22 status]

Some of the costs of UO-22 had been borne by the organization SatelLife, formed by International Physicians for the Prevention of Nuclear War, an organization which had received a Nobel Peace Prize in 1985.

HealthNet. SatelLife used the pacsat to start HealthNet, an international not-for-profit E-mail network for health professionals. Early users included five African medical schools which linked up with HealthNet to receive fresh medical literature and exchange electronic mail by satellite.

HealthNet message packets were transmitted on non-amateur frequencies near 428 MHz, not far from UO-22's amateur downlinks at 435 MHz. When off-duty from HealthNet, UO-22 would switch to amateur radio frequencies.

In congestion very similar to the UO-14 overcrowding problem, hams using UO-22 were limiting access for non-amateur SatelLife stations even as the non-amateur transmissions interrupted amateur activity. Surrey had obligations to SatelLife and VITA, so it moved to resolve the congestion in 1992.

Amateur radio service was dropped from UO-14 altogether in favor of non-amateur SatelLife and VITA and all ham activity was moved to UO-22. Today, however, UO-22 and UO-14 work for radio amateurs.

Imaging payload. UO-22 is a pacsat with bbs, but the satellite's most remarkable feature may be its charge-coupled device (CCD) television camera with 110-degree wide-angle lens showing a field of view nearly the same size as the satellite's footprint.

UO-22 snaps three or four shots a day, each of a ground area 994 by 1118 miles. Notable pictures have included Italy, showing the familiar boot outlined by the Mediterranean, Adriatic, and Tyrrhenian Seas, and Yugoslavia and Greece; an Antarctic iceberg; Bulgaria and Romania; Denver; Cuba and Haiti; Denmark and the Netherlands; haze over Djibouti, Somalia and Yemen; French Guyana; eastern South Africa; Egypt and Sinai, the Nile Valley and the Upper Nile; the Gulf of Mexico; Equatorial Africa; Kuwait and Persian Gulf smoke plumes; Limerick, Ireland; the Balkans; North Africa; the Great Lakes; northern Australia; Florida and the Mississippi Delta; Spain, Portugal and Mahgreb; California; the Red Sea; Korea; and the Straits of Hormuz.

The 110-lb. hamsat also carries radiation dose experiments, horizon sensors, and magnetometers, one inside and the other on a small boom protruding above the spacecraft. UO-22 has a 15-ft. gravity-gradient boom with a five-lb. weight on the end which provides restoring torque to keep the camera lens and radio antenna pointed to Earth.

Her Majesty Queen Elizabeth II was touring the UoSAT control room in 1992 when UO-22 flew overhead and transmitted a synthesized-voice greeting. Then another hamsat, UO-14, delivered a message to Her Majesty from President Fredrick Chiluba of the Commonwealth nation of Zambia. The Queen left a reply message which was returned to Zambia by UO-14.

1990s hamsats:     Microsats     UoSATs     Radiosputniks     Mini-Sputnik     Fuji     Badr     KITsat     Top of this page

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