BeeSat-1
BeeSat is a Picosatellitenprojekt at the Technical University of Berlin. BeeSat met the CubeSat standard and thus has external dimensions of 10x10x10 cm and a total mass of less than 1 kg. The main objective of the project is the verification of newly developed space, miniaturized reaction wheels and other technologies for pico satellites. So application fields are opened and the special benefits greatly miniaturized satellites are further utilized. The successors are Beesat -2 and Beesat - third
Mission Objectives
Ostensible goal of BeeSat is, even for picosatellites to develop technologies that have long been available for larger satellites and tested. A number of mission scenarios assume a working position control, which is why BeeSat to pilot a number of miniaturized components in this field.
Among other BeeSat flies with newly developed, highly miniaturized reaction wheels, sun sensors based on position sensitive devices and solenoids in PCB design. In addition to a number of other Picosatellitentechnologien like a new on-board computer ( 2 redundant ARM - based microcontrollers 7, 60 MHz) and a complex energy board to be tested.
Start
BeeSat was placed in a sun-synchronous orbit on 23 September 2009 with an Indian PSLV rocket. After the Launch and Early Orbit Phase, in which, as at University of satellites common to a number of ground stations are encouraged to track the satellites and to report contacts, BeeSat will then perform its experiments and provide services for radio amateurs, among others, as a digipeater.
Specifications
Energy supply system
The electrical energy for the operation of the satellite is generated by means of triple junction GaAs solar cells. At the end of the planned service life, minimal, generated from the sunlight power is still about 1.36 W at the while the average power consumption of 0.5 W was fixed. It is recognized by the energy board to document the condition of the satellite and to intervene with any deviations from the norm 38 Housekeepingdaten.
Attitude control system
A sun sensor for position control on the basis of a position sensitive device is provided on each side of the satellite, by means of which the relative orientation can be determined from the sun. Two three-axis magnetic field sensors measure the Earth's magnetic field. From solar and magnetic field measurement can then using various models ( train, solar and Erdmagnetfeldmodell ) the orientation of the satellite are determined in space. In addition, three arranged at right angles Gyros still be used as reference tools. By means of reaction wheels can then be taken to the predetermined position and influence of the satellite will be directed towards its target. To desaturate the reaction wheels 6 solenoids are used.
Board computer
The relatively complicated calculations of the onboard software (mainly the attitude control system ) are carried out with two redundant ARM -7 based microcontrollers with a clock speed of 60 MHz. There is a 16 -Mbyte program memory into which can also be loaded after starting software by telecommand. The onboard computer recorded 48 analog data on the condition of the satellite and stores them in a 4 Mbyte memory telemetry.
Communication system
The satellite will send with the call sign DP0BEE in the 70 -centimeter band around 436 MHz. The transmit power is 0.5 W at a 9600-4800 bit / s switchable downlink rate. The uplink is done in half-duplex operation at 4800 bit / s In addition, radio beacons and digipeater be provided for radio amateurs.
Camera
With the on-board camera images are to be taken from the surface and then sent to the base station for analysis. It also serves as an additional means of verification of the position control. A sensor with 640 x 480 pixels is used in front of which sits a Bayer mosaic filter. The color depth is 8 bits per component, and the images are compressed with adjustable compression.