AMSAT-OSCAR-40, also known as AO-40 or simply OSCAR 40,
[
] was the on-orbit designation of an
amateur radio satellite
An amateur radio satellite is an artificial satellite built and used by amateur radio operators. It forms part of the Amateur-satellite service. These satellites use amateur radio frequency allocations to facilitate communication between amate ...
of the
OSCAR
Oscar, OSCAR, or The Oscar may refer to:
People and fictional and mythical characters
* Oscar (given name), including lists of people and fictional characters named Oscar, Óscar or Oskar
* Oscar (footballer, born 1954), Brazilian footballer ...
series. Prior to launch, the spacecraft was known as Phase 3D or "P3D". AO-40 was built by
AMSAT
AMSAT is a name for various amateur radio satellite organizations worldwide. In particular, it often refers to the Radio Amateur Satellite Corporation, headquartered in Washington, D.C. AMSAT organizations design, build, arrange launches for, a ...
.
AO-40's project manager was Peter Guelzow of AMSAT-DL, the German AMSAT organization. Mr Guelzow holds amateur
call sign
In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally as ...
DB2OS.
History
Design, construction and launch
Following the failure of the Phase 3A launcher, design studies were undertaken and construction started for two successor satellites, that became AO-10 (Phase 3B) and AO-13 (Phase 3C) respectively.
After the launch of AO-13, design commenced for a Phase 4 satellite. This idea was later shelved, and design of Phase 3D (on-orbit name: AO-40) was undertaken under direction of the project team based in Germany, involving
amateur radio
Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emer ...
payloads from many countries in
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
.
Assembly was done at AMSAT's Spacecraft Integration Facility in the 'Free Trade Zone Building' at the Orlando International Airport,
Orlando, Florida
Orlando ( ) is a city in and the county seat of Orange County, Florida, United States. The city proper had a population of 307,573 at the 2020 census, making it the fourth-most populous city in Florida behind Jacksonville, Florida, Jacksonville ...
from 1994 to 2000.
It was launched on 16 November 2000, on an
Ariane 5
Ariane 5 is a retired European heavy-lift space launch vehicle operated by Arianespace for the European Space Agency (ESA). It was launched from the Guiana Space Centre (CSG) in French Guiana. It was used to deliver payloads into geostationar ...
launch vehicle from
Kourou
Kourou (; ) is a commune in French Guiana, an overseas region and department of France in South America. Kourou is famous for being the location of the Guiana Space Centre, the main spaceport of France and the European Space Agency (ESA). It ...
, in
French Guiana
French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...
, and reported cost was US$4.5 Million.
Operational problems
On 13 December 2000 at 11:23
UTC
Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...
, transmissions from AO-40 ceased during the exercising of its 400
newton motor. The Command Team were able to infer that there had been an explosion caused by pressure in the propellant pipes caused by malfunction of the control valves. A protective cap that was supposed to be removed from the motor before launch, was left in place. This error occurred because of a difference between the venting mechanism of the 400N motor used in AO-13 and the one in AO-40, complicated by a misunderstanding between the propulsion team and the engine manufacturer. When the motor was fired, pressure built up where it shouldn't, and destructive failure occurred. The loss of the motor caused AO-40 to be left in an equatorial orbit that the satellite was not designed for.
As a result of this incident several pieces of radio equipment no longer functioned or were not able to be commissioned. Following strenuous efforts by the Command Team, signals were restored on 25 December 2000 at 2145 UTC when Command Team member Ian Ashley (amateur radio call sign ZL1AOX) of
New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
successfully sent a 'reset' signal to the satellite. Onboard cameras were used to establish the attitude of the satellite, and the
magnetorquer
A magnetorquer or magnetic torquer (also known as a torque rod) is a satellite system for Spacecraft attitude control, attitude control, detumbling, and stabilization built from electromagnetic coils. The magnetorquer creates a magnetic dipole that ...
system was used to
spin-stabilize the satellite.
During June 2001, gas from the arcjet thruster was vented during apogee to raise perigee and stabilize the
orbit
In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...
of the satellite. Because of issues with the initial 400N burn, the apogee of the spacecraft was considerably higher than initially designed, but this was not a major issue. Subsequently, the communication packages and cameras were gradually re-activated.
Failure
On 25 January 2004,
telemetry
Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', 'far off', an ...
from the main battery was observed to go to an extremely low voltage by Stacey Mills (amateur radio call sign W4SM), a member of the Command Team. This caused the onboard Internal Housekeeping Unit (IHU)
computer
A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...
to cut power to the
transponder
In telecommunications, a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of ''transmitter'' and ''responder''.
In air navigation or radio frequency identification, a flight trans ...
payloads. Earlier in the same orbit the progressive drop in voltage caused the auxiliary battery to come online in parallel with the main battery. However the auxiliary battery was not being maintained in a charged state. Tying the two batteries in parallel did not result in an obvious change in voltage, but meant that the auxiliary battery could not be tested independently. Many attempts were made to disconnect the main battery, but insufficient voltage was available to drive the relays. It is possible that one day an open-circuit failure may occur in the main battery, in which case the spacecraft may come to life again via the auxiliary batteries. However, for reasons discussed below this is highly unlikely. The command team believes that the main battery failure was probably a consequence of damage done during the initial explosive event, and it is likely that similar damage was done to the auxiliary battery, making an eventual recovery of AO-40 unlikely. It is clear that the initial explosion blew open the end of the spacecraft to which the omni antennas were attached. This exposed the underlying batteries to major fluctuations in temperature and the explosion itself may have caused physical damage to the cells.
Following this final failure, the new keplerian elements have persistently shown an increase in orbital period corresponding to an increase in the semi-major axis of AO-40's orbit by approximately 2.7 km. Assuming AO-40 had a mass of 400 kg, this change required approximately 160,000 joules of energy directed along the velocity vector of the orbit. Since an explosion would be unlikely to focus its energy so precisely, it is likely that a considerably larger explosion occurred synchronous with the final battery failure. The source of this energy release is unknown, but it strongly suggests that recovery will not occur. (W4SM)
On 9 March 2004, Colin Hurst (amateur radio call sign VK5HI) of
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
, a member of the command team, heard a change in the level of radio noise at the expected
beacon
A beacon is an intentionally conspicuous device designed to attract attention to a specific location. A common example is the lighthouse, which draws attention to a fixed point that can be used to navigate around obstacles or into port. More mode ...
frequency
Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...
during the period 0310 to 0320 UTC (orbit 1541).
All telemetry captured by the command team, and its network of helpers, is archived on the web at the
AMSAT
AMSAT is a name for various amateur radio satellite organizations worldwide. In particular, it often refers to the Radio Amateur Satellite Corporation, headquartered in Washington, D.C. AMSAT organizations design, build, arrange launches for, a ...
website.
External links
*
AO-40 status information (AMSAT Germany)
in German and English
References
{{OSCAR satellites
Amateur radio satellites
Satellites orbiting Earth