Bexus 5 ready for launch

Jörgen Hedin,
the student projekt manager

The launch of Bexus 5


Campaign information BEXUS  5 (2007)






BEXUS (Balloon EXperiment for University Students) is a student payload that students at the Department of Space Science in Kiruna carry out together with students from Hjalmar Lundboms skolan and the space high school, Rymdgymmnasiet.

After lift off, the balloon did ascend to about 25 km ceiling. Ceiling was maintained for 2,5 hours to achieve maximum range for additional testing of the SSC E-Link system performance.

The campaign was carried out under the provisions laid down in the Esrange/Andöya Special Project agreement (EASP). Sweden was the main user in this flight.

Read more about the project on the student web page for Bexus 5.



Launch site: Esrange Space Center

Campaign period:

March 20 to April 4, 2007 
Launch date: 28 March 2007
Customer: SNSB (Swedish National Space Board)

The objective is to strengthen the cooperation between the space educations in Kiruna and to give the students inspiration to participate in space related projects. Esrange E-Link high speed TM/TC system units will be qualified for future operational use.
The condition of the Earths atmosphere will be studied and measured. The ozone content and cosmic dust particles will be measured.
Solar panels will be operated, camera pictures will be taken and Bluetooth will be operated for internal short distance communications during flight. Seeds will also be exposed for extreme temperature.
Read more at the REXUS4/BEXUS5 page.



Funding agency: SNSB (Swedish National Space Board)
Principal investigator: Mr. Jörgen Hedin, student payload manager, Department of Space Science,
Launch contractor: SSC
Research organizations:

Department of Space Science , University of Luleå (affiliate in Kiruna Space Camp)

Contact persons: Mr. Ola Widell, SSC project manager, Esrange Space Center
Mr. Peter Lindström, SSC project manager for E-Link
Mr. Jörgen Hedin, student payload manager, Department of Space Science, University of Luleå



Launch technic: Dynamic release technic
Balloon: Zodiac
Balloon volume: 12.000 m3
Gas: Helium
Hight: 25 km
Flight time: 3,5 h
Balloon systems:


Scientific instrument: The payload was designed and developed by students from the Department of Space Sciencestudents from
Payload service systems: The payload service system is designed and developed by SSC engineers and students from the Department of Space Science
Gondola weight: 30 kg




Experiments from the Department of Space Science, Sweden
ASDS - Attitude Sensing and Determination System
Objective: To determine movements as well as flight path of the payload platform in real time.
Method: ASDS is an attitude determination and sensing unit for the student balloon project BEXUS. The design is based on a 3-axis magnetometer determining the earth's magnetic field vector. It will be complemented by two 2-axis accelerometers based on MEMS technology sensing the forces acting about the gondola and determining the gravity vector. Furthermore a 3-axis gyroscope also based on MEMS technology is implemented to sense the rate of change thus combined with the accelerometer information the tilting of the gondola will be determined.
The experiment transmits the data to the ground station and will be displayed in a 3D-software showing the whole flight path with the orientation of the gondola in realtime.

FTC - flight trajectory computation
Objective: To evaluate the accuracy of flight trajectory computations.
Method: The experiment uses six 3-axis accelerometers positioned at different locations throughout the box. By using a designed Matlab algorithm these accelerometers can give the accelerating vector of the experiment as well as the rotational motion in relation to the center of rotation of the gondola. A digital tilt compensated compass is used to give the orientation of the box in relation to the earth’s magnetic field. The compass is also equipped with a gyro that can be used to compare the actual rotational motion to the calculated one. The experiment transmits the data to ground but can also store locally.
The data analysis will be done after the flight.
3.1.3 MMSP, multi motif stratospheric photography
Objective: To take a large number of high resolution photos and video recordings during flight.
Method: This experiment will use a 8Mpixel digital camera with a 4Gb memory card. The camera is mounted inside a protective aluminium casing with the ability to change it's direction of view by 180 degrees. It will store about 500 photos and 120 minutes of video during the flight and is remote controlled to run special photo routines at times of special interest such as launch and cut-off.

PEM - payload environment monitoring
Objective: To measure the temperature the payload is exposed to during flight.
Method: Four sensor cards will be placed on each side of the payload.
Each sensor card contains a NTC thermal resistor and a photo transistor. The photo transistor keeps track of which sensor is exposed to sunlight and what influence that has on the temperature. The NTC is calibrated to record temperatures spanning from -80 to +80 degrees Celsius, +- 1 degree. The temperature and level of sunlight intensity is sampled each second and stored locally onto EEPROM memories on the motherboard for post flight processing.

Experiments from the Würzburg University, Germany
CANSAT - A satellite in a can
Objective: Measure temperature, pressure and humidity levels localized with GPS coordinates
Method: The CANSAT incorporates GPS measurements with temperature (+-2 degrees), pressure (+-6kPa to 0 degrees, temperature compensated below
this) and humidity (+-3.5% RH) sensors. The sensor data is relayed to ground every fourth second and will be processed and used to derive atmospheric and meteorological data to predict cloud formation. The temperature data will also be used to calculate heat flux through the CANSAT structure and evaluate the quality of the insulation.

Experiments from Kiruna High schools, Sweden
Space High School
ARSEX – Auroral Recording Sound Experiment.
Objective: Recording of auroral sounds and the soundscape in the sub-arctic stratosphere.
Method: This experiment uses a handheld 4 channel mp3 recording device. This gives a total recording time of about 3 hours. Two channels are used for stereo recording inside E-Gon. The third channel has a VLF (Very Low Frequency) antenna and the last channel a regular microphone fastened a bit away from the payloads.

Hjalmar Lundbom High School
Passive experiments in a separate box. The box is containing various passive experiments. 

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