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UoSAT-12
UoSAT-12: The Mission

UoSAT-12: The Mission

No longer operational, UoSAT-12 was the twelfth satellite in the University of Surrey series, and was designed and built by SSTL and launched to low Earth orbit on 21 April 1999.

UoSAT-12 was an experimental mission used to demonstrate and test a number of new technologies, including imaging cameras and a high-speed 1 Mbit/s S-band downlink (the MERLION experiment) were tested. An Internet Protocol stack was uploaded to the satellite, allowing experiments in extending the Internet to space to be made by NASA Goddard as part of its Operating Missions as Nodes on the Internet (OMNI) effort.

Achievements

UoSAT-12 was the first satellite to have a web address in orbit
On 25th January 2001, UOSAT-12 became the first web server in space when an Internet Protocol stack was uploaded to the satellite, allowing experiments in extending the Internet to space to be made by NASA Goddard as part of its Operating Missions as NOdes on the Internet (OMNI) project. 

UoSAT-12 was the first satellite to use Nitrous Oxide as a propellent in an experimental resistojet thruster.  It used 100W of power, achieved 50mN of thrust and it ran at up to 1000 degrees centrigrade.  

UoSAT-12 was also the first satellite to demonstrate autonomous orbit control using on-board GPS and the propulsion system to maintain a drag-free orbit over a period of months.  
In September 2000, the autonomous orbit control system developed with Microcosm USA,  on-board UoSAT-12 operated continuously for 29 days and demonstrated accurate autonomous in-track orbit control under the adverse conditions of long GPS outages and an initial halving of thrust followed by a return to full thrust midway into the run.

The launch of UoSAT-12  represented the first commercial mission on the DNEPR rocket,  converted from the former Soviet Union's arsenal of SS-18 Satan missiles (all of which have to be destroyed or used for peaceful purposes under the START arms reduction treaty). The DNEPR vehicle was created in 1997 under an agreement between the Russian and Ukrainian space agencies.

In January 2000, UoSat-12 imaged a lunar eclipse.

UoSat-12 provided over 4 years of service life. 


Technology demonstrations

Star cameras (Star0 and Star1)

SGR (Space GPS Receiver) - The SGR-20 was an ESA-funded GPS Receiver  in partnership with SSTL

Autonomous orbit control demonstration - In Sept. 2000, OCK operated continuously for 29 days and demonstrated accurate autonomous in-track orbit control under the adverse conditions of long GPS outages and an initial halving of thrust followed by a return to full thrust midway into the run.

Propulsion systems
UoSat-12 incorporated two separate propulsion systems, a compressed nitrogen cold gas system and a nitrous oxide resistojet system. 

The N2 cold gas system was used for attitude control and velocity change whereas, the resistojet is a technology demonstrator primarily used for velocity change. 

EPS (Electric Propulsion System). EPS was an experimental resistojet electric propulsion system developed at theSurrey Space Centre. Water on nitrous oxide is super-heated over a resistive heater element, the resulting hot gas is expelled through a nozzle to produce low-level thrust at moderate specific impulse. The thruster provides a thrust of 93 mN, using 90 W of input power, the Isp is 1250 m/s. A total ΔV of 10.4 m/s is provided by a 2-liter tank of self-pressurized nitrous oxide. 
 

Satellite Data

Name:
UoSAT-12

Customer:
SSTL

Mission:
Earth Observation and Technology Demonstrator

Mass:
312kg

Platform:
SSTL-400

Launch Data

Launch Date:
21 April 1999

Launch Site:
Baikonur Cosmodrome, Kazakhstan

Launcher:
DNEPR

Orbit:
650km sun-synchronous

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