UoSAT-2, which is also known as UO-11 and OSCAR-11, is a British satellite orbiting in Low Earth Orbit. The satellite functions as an amateur radio transmitter (known as an OSCAR) and was built at the University of Surrey. It launched into orbit in March 1984 and remains orbital and active, though unstable with irregular periods of transmission. All of the Analog telemetry channels have failed, making telemetry from OSCAR 11 useless. The satellite was still heard transmitting telemetry in 2015, thirty years after launch.[3][4]
Operator | University of Surrey[1] |
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COSPAR ID | 1984-021B[2] |
SATCAT no. | 14781 |
Spacecraft properties | |
Manufacturer | SSTL |
Launch mass | 60 kilograms (130 lb) |
Start of mission | |
Launch date | 1 March 1984, 17:59 (1984-03-01UTC17:59Z) UTC |
Rocket | Delta 3920 |
Launch site | Vandenberg SLC-2W |
Orbital parameters | |
Reference system | Geocentric |
Regime | Sun-synchronous |
Inclination | 98.25 degrees |
OSCAR ← OSCAR 10 OSCAR 12 → |
It was operated by Surrey Satellite Technology Ltd. (SSTL).
The satellite was the second in the UoSAT series of satellites built by University of Surrey; preceded by UoSAT-1 and followed by UoSAT-3.
The satellite carries a Digitalker speech synthesiser,[5][6] magnetometers, a CCD camera, a Geiger-Müller tube, and a microphone to detect the vibrations of micrometeoroid impacts.[6] Like UoSAT-1 it transmits telemetry data on the VHF beacon at 1200 baud, using asynchronous AFSK,[7] though now all analogue telemetry channels have failed;[8] on an FM receiver the audio signal resembles the cassette data format of the contemporary BBC Micro computer.[6] Actually it is a BASICODE signal, but no citation. Slight modulation had also been observed on the S band beacon.[9]
UoSAT-2's solar arrays were bought at a premium compared to those of UoSAT-1, the design having been space tested by its predecessor.[6]
The British affiliate of AMSAT distributed a library of software for the BBC Micro to track UoSAT-2 and other satellites and analyse telemetry broadcasts.[10] A commercial fixed-frequency receiver, Astrid, was also produced by British firm MM Microwave[11] for the education market, with accompanying BBC Micro software to display raw telemetry frames. For versatility the Astrid set included a demodulator to load signals through the serial port of any computer.[6]
As it went around the earth it encountered data upsets, geo-located around the South Atlantic anomaly.
According to a February 2008 status report the satellite had no viable battery backup, operating only from its solar panels, and a watchdog timer on board was suspending activity for up to three weeks following any power anomaly. At the time of the report it was experiencing continuous sunlight for the last time, with the prediction that "permanent eclipses" in its orbit would begin in the middle of March 2008, limiting transmissions to "a short time, possibly less [than] a single orbit, every 21 days."[8] By April 2008 the updated prediction was that eclipses would continue until 2019.[12]
After a 21-month gap in observations, UoSAT-2 resumed sending telemetry sometime before 10 December 2009, and is apparently continuing the watchdog-controlled transmission regime, though now on a ten-days-on, ten-days-off schedule. Its condition has not otherwise improved apart from some recovery of battery power, allowing broadcasts to continue into each eclipse.[10]
Current observation reports for UoSAT-2 can be viewed and logged at the Oscar Satellite Status Page.[4]
The satellite was instrumental in providing a communications link, known as Nordski Comm, from the Ski-Trek support teams to the expedition party. The position of the skiers' emergency beacon was calculated daily by Cospas-Sarsat ground stations and relayed to them, and thousands of amateur radio listeners, as a spoken message from the Digitalker on board UoSAT-2. The message could also serve as an emergency channel to the skiers in the event that all other radio links failed.[5][13]
UoSAT satellites | |
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See also: Surrey Satellite Technology Ltd. (SSTL) |
OSCAR satellites | ||
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Satellites |
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← 1983 · Orbital launches in 1984 · 1985 → | |
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Kosmos 1522 · Kosmos 1523 · Kosmos 1524 · Kosmos 1525 · Kosmos 1526 · Kosmos 1527 · Kosmos 1528 · Kosmos 1529 | Kosmos 1530 | Kosmos 1531 | Kosmos 1532 | Yuri 2a | Kosmos 1533 | Kosmos 1534 | Shiyan Tongbu Tongxing Weixing 1 | OPS 0441 | Kosmos 1535 | STS-41-B (Westar 6 · Palapa B2 · IRT · SPAS-1A) | OPS 8737 · OPS 8737 SSU-1 · OPS 8737 SSU-2 · OPS 8737 SSU-3 | Kosmos 1536 | Soyuz T-10 | Ōzora | Gran' No.25L | Kosmos 1537 | Progress 19 | Kosmos 1538 | Kosmos 1539 | Landsat 5 · UoSAT-2 | Kosmos 1540 | Intelsat V F-8 | Kosmos 1541 | Kosmos 1542 | Kosmos 1543 | Kosmos 1544 | Ekran No.26L | Molniya-1 No.51 | Kosmos 1545 | Kosmos 1546 | Soyuz T-11 | Kosmos 1547 | STS-41-C (LDEF) | Shiyan Tongbu Tongxing Weixing 2 | Kosmos 1548 | OPS 7641 | Progress 20 | OPS 8424 | Kosmos 1549 | Gorizont No.19L | Progress 21 | Kosmos 1550 | Kosmos 1551 | Kosmos 1552 | Kosmos 1553 | Kosmos 1554 · Kosmos 1555 · Kosmos 1556 | Kosmos 1557 | Spacenet 1 | Kosmos 1558 | Progress 22 | Kosmos 1559 · Kosmos 1560 · Kosmos 1561 · Kosmos 1562 · Kosmos 1563 · Kosmos 1564 · Kosmos 1565 · Kosmos 1566 | Kosmos 1567 | Kosmos 1568 | Kosmos 1569 | Kosmos 1570 | Intelsat V F-9 | Kosmos 1571 | USA-1 | Kosmos 1572 | Kosmos 1573 | Kosmos 1574 | Gran' No.27L | Kosmos 1575 | USA-2 · USA-3 | Kosmos 1576 | Kosmos 1577 | Kosmos 1578 | Kosmos 1579 | Kosmos 1580 | Kosmos 1581 | Meteor-2 No.16 | Soyuz T-12 | Kosmos 1582 | Kosmos 1583 | Kosmos 1584 | Kosmos 1585 | Gorizont No.20L | Kosmos 1586 | Himawari 3 | ECS-2 · Telecom 1A | Kosmos 1587 | Kosmos 1588 | Kosmos 1589 | Molniya-1 No.53 | Progress 23 | Kosmos 1590 | CCE · IRM · UKS · SCE | Molniya-1 No.54 | Ekran No.27L | USA-4 | Kosmos 1591 | STS-41-D (SBS-4 · Leasat 2 · Telstar 3C) | Kosmos 1592 | Kosmos 1593 · Kosmos 1594 · Kosmos 1595 | Kosmos 1596 | USA-5 | Fanhui Shi Weixing 7 | Kosmos 1597 | Kosmos 1598 | Galaxy 3 | Kosmos 1599 | Kosmos 1600 | Kosmos 1601 | Kosmos 1602 | Kosmos 1603 | Kosmos 1604 | STS-41-G (ERBS · OSTA-3) | Kosmos 1605 | Nova 3 | Kosmos 1606 | Kosmos 1607 | STS-51-A (Anik D2 · Leasat 1) | Spacenet 2 · MARECS-2 | NATO 3D | Kosmos 1608 | Kosmos 1609 | Kosmos 1610 | Kosmos 1611 | Kosmos 1612 | Kosmos 1613 | USA-6 | NOAA-9 | Molniya-1 No.55 | Vega 1 | Kosmos 1614 | Kosmos 1615 | Vega 2 | USA-7 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets). |