|
Jörgen Hedin Department of Space Science (IRV) jorhed-03@ryp.umu.se Electronics, electromechanics, programming |
 |
Michael Erneland Department of Space Science (IRV) micern-03@ryp.umu.se Design, mechanics, thermodynamics |
Visit the BEXUS5 campaign main website.
MMSP was successfully launched with BEXUS 5 from Esrange Space Center on the 28:th of March 2007.
 This picture was taken from a height of 25km above Rovaniemi, Finland. The camera was pointing west with the Swedish/Norweigan mountains at the horizon. This picture can be downloaded in full 8MPixel resolution here (3.7Mb). A 20 minute video started directly after the picture above was taken and can also be downloaded here (40.1Mb). Use VLC media player to watch the video http://www.videolan.org/vlc/. During the flight that endured for about 3h a total of 454 pictures and 105 minutes of video was recorded with a total size of 3,41Gb. |
|
|
|
|
|
 You´re now visiting the project homepage of MMSP - Multi Motif Stratospheric Photography. MMSP is a Swedish university project performed by two students at the Department of Space Science in Kiruna, Sweden. This project will fly(was flown) on board the high altitude balloon BEXUS 5. This campaign is made reality through a collaboration between the Swedish Space Board, Swedish Space Corporation, Esrange Space Center and the Department of Space Science. Apart from MMSP, four other student experiments will fly with the BEXUS 5 campaign. This flight is a unique opportunity for students at the department of space science to design, develop, build and fly their own experiments in subspace conditions. The balloon has a total volume of 12.000 cubic meters and grows to a diameter of 50 meters when the maximum altitude is reached. It has a capacity to carry about 150kg of experiment payload to an altitude of 30 kilometers. This gives the students a challenging environment to test their experiments in with temperatures as low as -70 degrees celcius and only one percent left of the airpressure at sealevel. |
Image credit: Swedish Space Corporation, Esrange Space Center balloon pad.
|
 One of MMSP:s objectives is to investigate if it's possible to take high resolution photos and video recordings from the payload during flight using a standard "off the shelf" digital camera. Where and when to take photos or to start video recordings will be controlled both by a preprogrammed routine aswell as real time commands sent from a groundstation during flight. Another great challenge with this project is to return the camera as functional and undamaged as it was before in order to keep a reasonable budget and to be able to use the camera normally when not in flight. This means that the camera has to be operated from the "outside" as the human hands would. Some great news is that due to the launch delay, there has been time to edge up this project even more. Instead of the Olympus C4000 Zoom 4MPixel camera with 128Mb originally meant to fly, a brand new Samsung DigiMax Pro 815, 8MPixel with 4Gb will serve as a nice replacement. This thanks to an unexpected but most welcome sponsorship from the Department of Space Science. 
In a short summary the MMSP project consists of a digital camera mounted on a stepper motor controlled disc fastened with two aluminium profiles about 50cm out from the payload structure. This disc makes the motif changes possible in a range of 180 degrees and will cover every interesting area worth of photographing. The main objective is to be able to present about 105 minutes of 640x480, 15fps, VGA video with stereo sound and about 500, 8MPixel, 28mm, wideangle photos. Hopefully as staggering as they will be interesting. This will help to understand how a stratospheric balloon payload actually behaves and what it's exposed to during flight. MMSP will also time synchronize its video recordings with the ASDS experiment also on board the BEXUS 5 payload. This will help validate their recorded data of the payloads movements with an actual optical view. Read more about the ASDS experiment and the BEXUS 5 campaign in general by following the link in top of this page. |
  This figure shows an simple overview of the different photo and video sequences that will be executed during flight. It's assumed that the balloon will reach its maximum floating altitude after about 120 minutes. The release and cutoff signals are realtime commands sent to MMSP from the groundstation as mentioned earlier. Sequence 1: TRelease -- T=10min A photo is taken every fifth second for a period of ten minutes with the camera pointing straight downwards. Sequence 2: T=10min -- T=60min Four photos are taken every minute for a period of 50 minutes. Every fourth minute it's time for a special routine that takes a photo about 45 degrees above the horizon then takes the three remaining photos close to and straight downwards. Those other minutes, the routine concentrates around the horiozon. Sequence 3: T=60min -- T=80min 20 minutes of video 640x480 @ 15fps with stereo sound recording. Varying directions from 45 degrees above horizon to straight downwards. Sequence 4: T=80min -- T=90min Same as sequence 2. Sequence 5: T=90min -- T=110min Same as sequence 3. Sequence 6: T=110min -- T=120min Same as sequence 2. Sequence 7: T=120min -- T=140min Same as sequence 3. Sequence 8: T=140min -- T=150min Same as sequence 2. Sequence 9: T=150min -- T=170min Same as sequence 3. Sequence 10: T=170min -- TCutoff A photo is taken every fourth minute. Three times at the horizon and the fourth straight downwards, until a cutoff signal is recieved from groundstation. Sequence 11: TCutoff The camera is pointed straight up and starts a 25 minute video capture 60 seconds before the actual cutoff to capture the release. Then turns down to watch the ground come closer. |
 |
|
The mainboard will be mounted inside the payload structure among with other experiments. The mainboards core consists of a microcontroller from Atmel model ATmega8. It's programmed with C and controls every function in MMSP. It's possible to reprogram the device through a RJ-45 connector on the circuit board using a special programmer adapted to Atmels microcontrollers connected to a PC.
First of all, photographing is made possible by a mechanical trigger soleniod connected via a HEXFET IRFD-120 from International Rectifier to the ATmega8. Due to the fact that the camera won't run on it's own battery, the camera needs to be supplied with 8,4V DC. This is made by regulating 12V DC from the MPEG payload powersupply with a National Semiconductor LM317AT. There are two stepper motors to control motif changes and function changes. Theese are unipolar steppers and have a SGS-Thomson ULN2803A eight darlington driver array connected to the ATmega8 for driving. |
 |
|
In this section you will be able to follow the work in progress. Worth to mention is that the project almost was completed with the C4000Z camera before it was decided that the better 815pro could be used.
The first day of work progress below starts from the first day of modifications to make everything fit the 815Pro. All theese pictures are also from the BEXUS IV campaign and the most important, recent pictures from the BEXUS 5 campaign can be found on top of this page. |
Summary: Disassembly and modification of the old camerabox to fit the new one.
|
|
|
|
|
|
|
Summary: Insulation fitting and adaption of the functionswitching steppermotor.
|
|
|
Summary: Fastening of a second ball bearing to add more stability. AVR-Programmer development.
|
|
|
|
|
|
Summary: Payload mounting. Stepper motor tests. DC-regulator adaption for camera powersupply.
|
|
|
|
|
|
Summary: Mainboard PCB development.
|
|
|
|
|
|
|
|
|
|
|
|
 We would like to send a special thanks to: Alf Wikström, Program manager, Department of space science - Initiator camera sponsorship. Leif Carlsson, Technician, Department of space sciece - Electronics equipment and component sponsor. Jessica Nyberg, Customer service, Atmel Nordic AB - Microcontroller sponsor. Roland Kjellman, Director, Kjellmans Service AB - Ball bearings sponsor. |
© 2007 Jörgen Hedin