Experiment Overview
The plan was to design, build and test the flight computer and especially the inertial measurement unit for next generation student rocket project of Castor the Space Club of Tampere University Of Technology. The experiment was succesfully launched on the REXUS 5 rocket in March of 2009.
The REXUS 5 sounding rocket is 6 meters long and it’s mass is 500kg. It has top speed over 1200 m/s and it will reach the apogee of 100km in less than 3 minutes having peak acceleration of almost 20g.
Castor is the Space Club of Tampere University of Technology. Castor has recently finished Finland’s most ambitious student rocket project (Supikoira) which was succesfully launched on 06-09-2008 in Rovajarvi (a military area in Lapland).
REXUS BEXUS is a bilateral German-Swedish cooperation to offer students opportunities to fly their own experiments on sounding rockets and stratospheric balloons. Half of the payload is reserved for German students, while the Swedish half has been made available to students from other European countries through a collaboration with ESA Education.
Objectives
- To test components for Supikoira 2
- To increase accuracy of the Inertial Measurement Unit
- To take the first Finnish images from Space
- To gain positive publicity for space research in Finland and Europe
- To gain valuable experience of space related projects
Design
Setup
The experiment consists of three units. Supikoira flight computer 2 (SFC2), Inertial Measurement Unit 2 (IMU2) and the Experiment Digital Camera (EDC). The SFC2 will record inertial measurement data from IMU2 and images from the EDC. IMU2 data will be recorded to onboard memory and the images will be recorded on external SD memory card.
Communication
SFC2 and IMU2 will be communicating over MIL-STD-1553 Bus. SFC2 and EDC will be communicating over Ethernet and a couple of digital IO lines. SFC2 will be also communicating to the ground station via radio uplink and downlink provided by the REXUS rocket. The REXUS communication is going over RS-422 serial link.
Hardware
** SFC2 **
SFC2 is the main board of the experiment. It is designed to be a flight computer for future uses and has advanced communication capabilities and powerful processors (ARM7 and Floating point DSP). Its responsibilities in the experiment are recording of the inertial measurement from the IMU2 and images from the EDC. The navigation data from IMU2 is forwarded to Kalman filter running in the SFC2. SFC2 sends the information provided by the Kalman filter to ground station via REXUS downlink.
List of SFC2 main components:
CPUs 72 MHz ARM7 MCU (NXP LPC2468)
225 MHz DSP (TI TMS320C6722BRFPA225)
RAMs 64 MB SDRAM (MT48LC32M16A2)
128 kB Dual port SRAM (Cypress CY7C028V)
Storage 8 kB FerroRAM (FM24CL64)
8 MB NOR Flash (AT49BV642D)
4x 2MB Data flash (AT45DB161D)
2GB Industrial SD-card (SG9SD2GSMEA1)
** IMU2 **
IMU2 is the inertial measurement unit of the experiment. It has accelerometers, gyroscopes and temperature-sensors. Electronics consist four different boards. Main unit, and a small board for X,Y and Z axis.
List of IMU2 main components:
CPU ARM7 MCU (AT91SAM7A3)
AD/C 16bit 6ch 250kSPS (AD7656)
Gyroscopes 3x Silicon Sensing (SiRRS01-07)
Accelerometers 3x Colibrys (MS8030.D)
** EDC **
EDC is the experiment digital camera. It is used to take images of the view outside the REXUS rocket for PR purposes.
List of EDC main components:
Camera Dalsa (Genie C1024) Optics f=8mm F: 1.4-C (NTL-SV-0814MP)
Software
Software consists of three distinct parts:
** 1. SFC2 software**
- Operating system: RTEMS
- HW drivers (UART, Clock, Timer, RTC, SD/MMC, MIL-STD-1553, Ethernet)
- Navigation software
- Logging
- MIL-STD-1553 bus controller
- Camera control
- Uplink/Downlink
- HW drivers written in C, other software in Ada95
2. IMU software
- Measures accelerations, angular velocities and sensor temperatures.
- Does sensor error compensation.
- Does integration of inertial measurements
- MIL-STD-1553 remote terminal
- Written in C
3. Ground software:
- Flight visualization
- Logging
- Written in Python/C/Ada95
With the exception of MIL-STD-1553 driver, software is developed on Embedded Artists LPC2468 prototyping board, while waiting for the actual hardware to finish. Navigation algorithms are prototyped with Python / Numpy, before implementation in Ada95.
Results
REXUS 5 was launched at 6:00 UTC at Esrange, Kiruna, Sweden. Apogee of the flight was about 88 km.
The experiment was working nice and it got 89 photos during the flight. Curvature of earth and the black space can be seen from couple of the images. There are also nice photos of clouds.
Team is currently analyzing the inertial data and will update the wiki according the upcoming results.