The goal of the project is to construct an atmospheric probe and equip it with different sensors. The probe will be mounted on a meteorological balloon, and lifted to approximately 35 000 m (115 000 ft). The ascent and descent will be recorded with two on-board GoPro cameras, and the probe will be tracked via GPS. The projects name is VIC GOES TO SPACE - all the students attend the VIC HIGH SCHOOL (VIC is pronounced EXACTLEY like witch :) )
This project requires a somewhat bigger group of students - around 30. It is best suited for older high school students, with a preference for natural studies (physics, chemistry and biology), and love for technical skills.
At the beginning of students were divided into teams, and each of them was assigned a specific tasks: adaptation of specific sensors, design of the probe, design of the parachute, adaptation of the data acquisition device (DAQ) and GPS device, preparation of the biological samples. During the building stage the groups had to communicate with each other in order to get optimal sensor results. Each team had to keep a work journal and make a detailed work report at the end (will be added).
Students used the VERNER sensors and DAQ – Vernier supplies most of the equipment to our school, so it was the most convenient choice for us. But you can use any kind of DAQ, sensors and GPS system you can get.
NOTE: Due to the current weather situation in Slovenija the launch date is somewhere in the beginning of march, but we published all of the test launches. The flight movie will be updated ASAP, so be sure to follow us :)
This instructable was written (except the intro) and edited by the students.
STUDENTS WILL RESEARCH THE FOLLOWING SUBJECTS
- atmospheric pressure
- UVA and UVB radiation
- ideal gas law, lift
- atmospheric gas composition
- Verner sensors datasheets
- living organisms in extreme conditions (extremophiles)
- electric current, Joule heat
- heat conductivity, thermal conduction
- GPS positioning systems
- air drag
- By disassembling the sensors, making adjustments and building the probe, the students will learn to handle hand tools, power tools, how to solder and use appropriate safety measures.
- Students will develop creative problem solving skills as they will have to deal with a number of technical issues. They will develop team communication, and will learn to constructively interacts with team members and other teams in order to reach the goal.
- By building a hot wire foam lathe students will learn about the practical use of Joule heating, Joules First Law, electric conductivity and effects of high temperature on different materials (pvc, Styrofoam, etc...)
- By designing and building a parachute the students will learn about air drag, terminal velocity and will learn to handle a sewing machine.
- By examining the microorganism the students will learn about the living conditions of the extremophiles and will be able to predict their survival rate in extreme conditions.
Step 1: Description of work/components
For the probe the following equipment must be provided:
- probe casing
- carbon dioxide sensor
- oxygen sensor
- pressure sensor
- temperature sensor
- bacteria (yeast and Cryptococcus)
- light sensor UVA and UVB
- pressure chamber
- GPS tracking unit
- data collection unit
We used the Vernier sensors, and modified them. They can be found at:
Step 2: Distribution of students into groups:
- constructors (probe, parachute, remodelling of sensors)
sensor groups (according to class):
- chemistry - carbon dioxide and oxygen measurements
- physics - air pressure and temperature measurements
- physics - UVA, UBV radiation and light measurements
- biology (yeast and extremophiles preparation)
Step 3: Construction of the DAQ, probe tracking (GPS)
- disassembly of this DAQ, removal of its casing and screen
- shortening of wires
- connecting the sensors to DAQ
The GPS unit we use is the BLACKBLOX GPS unit, can be bought HERE.
Step 4: Making the hot wire lathe
Before making a probe, you will first have to make a ''lathe''. First make the wooden holders for the end plates. For the end plates you can use any rod or stick, as long as it is thick enough to mount a plate on its end. Just place them into a ball baring and attached to the wooden holders. Then put a round or square plate on each of them. We used 25 mm thick aluminium rods and for the ends we used round aluminium plates (diameter 100 mm and 135 mm).
In between two end plates you will later put the polystyrene block.
With lab stands and some clamps you can make a stable holder for the hot wire.
Step 5: Construction of the probe casing
You will need:
- probe casing design (plan)
- hot wire lathe for Styrofoam
- of test probes
- cutting the probe casing out of polystyrene
- making holes for sensors
- making flaps
The probe should also be equipped with flaps, which will stabilize it during flight.
On the top and bottom cut two additional grooves, in which you will place two metal rings - they will hold both halves of the probe together.
Step 6: Carbon dioxide (CO2) and oxygen (O2) sensor
- sensors must be cut out of their plastic casings
- be very careful not to damage the sensor when using the cutting disk
- trim the plastic casing until the interior of the sensor can be taken out of it
- peel down the plastics surrounding cables and shorten them
- solder the cables together
First dissemble the sensors. While doing this be very careful not to damage them while cutting them out of their plastic casing. Trim the casing until the interior of the sensors can be removed from it. Then shorten the cables and trim the thick plastic surrounding them. Solder the shortened cables back together.
Step 7: Heated pressure chamber
- air pump
- electric heater (wire for the terrarium)
- plastic bottle
- air pump - electric pump used for model submarines
- resister wire - we used constantan wire
For the heating element you can place the resistor wire between two layers of silvertape. If the wire gets too hot it will melt the tabe though - so be careful not to overdo it.
We used an old spring scale in a tube. All we did was put an O-ring on the outer end and drill doles in the inner one. Then we used silicone to glue it to the chamber - and it worked !
Step 8: Pressure and temperature sensor modification
- select appropriate pressure and temperature sensors (gas pressure sensor and thermometer)
- reduction of mass (removal of unnecessary parts)
- shortening the cables
- removing the sensor casings (plastics and protective parts)
- testing the sensors (before and after having removed the casing) !!!
Step 9: Live crew - yeast and extremophiles
- use plain yeast (from baking yeast) and extremophiles – Cryptococcus (isolated from glacier material)
- you will need a nutrient medium: we used: RIDA®COUNT Yeast and Mold Rapid
- place the bacterial culture on the nutrient medium
- incubation: temperature 24°C, 48 hours (a new generation of fungi grows every 2 hours)
- measure the number of cells in the sample: we used the Vernier photospectrometer
- compare the growth of bacteria in ideal conditions and under extreme conditions (you can do that after the probe returns)
Step 10: Light sensor modifications
- modify the UVA (ultraviolet radiation type A) and UVB (ultraviolet radiation type B) radiation and light sensor
- remove long handles intended for a better grip and easier use
- shorten cables connecting the sensor with a data acquisition device
- remove light sensor casings
- install sensors in the probe facing upwards !!! (the probe will rotate throughout its travel and the sensors will not be exposed to constant light source all the time, but you will get the information about the probes rotation)
Step 11: Cameras
One camera will record the side view, and the other the down view. As we plan to launch in the early morning hours, we hope to capture the moment of the sunrise :)
Step 12: The PARACHUTE
In order to test the optimal design we designed three different types of parachutes:
- A plastic trash bag parachute (duct taped together)
- B textile parachute (cotton fabric - didn't work at all!)
- C sewed plastic parachute
If you are going to make your own you should first:
calculate the estimate weight of the load and then make an appropriate stencil for the parachute gores. We found the calculations at:
Then you should:
- make a stencil for a parachute gore (ours had a diameter of 1,5 m)
- 8 large trash bags (one for each gore)
- cut the trash bags using the stencil, and use a sewing machine or duct tape to bind the gores together
- attach 8 strings 2,5 meters long, one on each gore
- you can make a hole in the top part of the parachute (the hole will help to open the parachute faster and will stabilize the fall)
After we made all three designs we went out and tested them. At the end we decided to go with the one that has a hole in the middle. We took the gore stencil to KIMFLY a local parachute manufacturer, and he made the parachute for us out of some special parachute fabric. After all trash bags at 115 000 ft didn't seem a good idea at all!
Step 13: Probe assembly
- cut out individual holes for the components
- insert and glue individual sensors
- connect the sensors to the DAQ
- set up the sensors
- check the sensors if they are working correctly
- test the pressure chamber and heating
- make place for extremophiles – Cryptococcus
At the end we install all the components inside the probe and assembly it all together. We position the components in the probe. We make the final probe casing and install the remodelled sensors, the camera, extremophiles and the parachute.
Step 14: Test launch
The testing was a success, and now all we need to do is wait for the right weather conditions and launch the probe. According to the national aviation agency we will be able to launch the probe on the 3rd of MARCH, so expect an update on the same day !!!
Step 15: THE LAUNCH
The balloon is connected directly to the top of the parachute, and the parachute directly to the probe. there is no direct connection between the balloon and the probe. After the balloon bursts the probe will start to fall freely and the parachute will open. As it descends toward the ground the air density will increase and so will the air drag. The speed of the probe will therefore decrease as it is approaching the ground.
The balloon will be filled with 10 m3 of helium. The starting balloon diameter will therefore be 2,3 m, and just before bursting the diameter will be 13 m!!!! (thats aloooooooot)
We expect to reach a lift velocity of 7 m/s and fall velocity of approximately 7 - 10 m/s. The probe will touch the ground after about 118 minutes of flight.