Detailed Description
DTUsat is a picosatellite designed and built by students from the Technical University of Denmark, DTU.
The main payload of DTUsat is an electrodynamic tether for dumping the satellite. The tether is deployed using a novel yo-yo system, greatly simplifying construction and deployment. A calibrated test transmitter is flown as secondary payload. The satellite is 3-axis stabilized using magnetorquers, while attitude determination is done by a combination of a 3-axis magnetometer and 5 chip scale dual-axis sun angle sensors designed and built for this satellite. The mass of each sun angle sensor including supporting electronics is only 3 g. All flight electronics is designed using modern 3.3V CMOS integrated circuits, lowering total power consumption to about 400 mW while providing about 10 MIPS for application software.
All electronics in DTUsat is commercial 3.3V small-geometry CMOS to conserve power. We have tested for Total Ionizing Dose, which caused a maximum of 50% power consumption increase over the projected radiation dose. This is well within the power envelope of the system. The first chips are tested to fail at a total ionizing dose of about 7 krad, which translates to about a year given our shielding and orbit. This is sufficient for the mission. We do not yet know the rate of Single Event Upsets, but we have designed a global protection system, that shuts down and reboots the entire satellite by turning off the power supply if a latch-up is detected. Latch-up detection is decentralized to local sensors. Due to lack of power, weight, and time, we have opted for a simple configuration with little redundancy.
|
