ISS Vaisala MW41 Radiosonde Launch Instructions

Based on https://docs.google.com/document/d/1RSNY7F9q0ZlcrJgbz1HjkCzdeuXJXwedNCoXYq-5mQ4/edit# (with extras)

• Allow ~20 minutes before launch to prepare sounding.
• Call SB Airport ATC 30 minutes before launch
• Bill Brown wbrown@ucar.edu 303-818-5232

Preparing the radiosonde

If the program is running from the previous launch:

• Close-out program and restart by clicking “terminate sounding” button.
• Initialize a new launch by putting a second radiosonde on the Vaisala ground check platform.

1. Save the radiosonde package because you will need the serial number stuck on it to fill in the sounding field log spreadsheet.
2. Do not touch the sensor tongue.
3. The software will tell you to it is ready to start the sonde ground checks
   • Place radiosonde on the Vaisala ground check platform. A conditioning window should pop up. This initializes the sounding and starts the conditioning and preparation process.

4. Setting the frequency: If a frequency window does not also pop-up, you can change the frequency in the conditioning window where it says “change” next to “frequency”. Manually choose a frequency where you see a trough or from the table below. Note the frequency. Click “Apply”. 

   
   

5. Allow the program to go through the ground checks – such that all the steps illuminate green. This can take up to 5 minutes.

6. When the ground check is complete, add the unwinder. It’s like a puzzle piece. You will hear it snap into place.
7. Bring the radiosonde outside on the setup platform so it can settle to ambient conditions and activate the GPS. Check the computer that data is being read and GPS is tracking the sonde. 
   • To know that the GPS is working – a green tick mark symbol replaces the exclamation point.

TROUBLESHOOTING:  If the radiosonde light starts to blink red during the conditioning process OR  the software doesn’t register the radiosonde at all then 

1. Shutoff the Vaisala box
2. Re-start the computer. When the computer is done re-starting, then turn on the Vaisala box - there will be a blinking green light for ~3-5 minutes. Be patient and wait for that blinking light to stop, then start the Vaisala software and run through step 3.
3. The radiosonde will continue to blink red through much of the conditioning process but should turn green when that step finished
4. If the radiosonde continues to blink red after conditioning, then replace the bad sonde and make a record of it.
5. Be sure to choose a frequency different from the one used in the first launch.

Filling the balloon

1. Attaching the regulator:
• Attach the cable to the Helium tank. Right hand gauge is for the Helium, Left hand gauge is attached to the regulator.
• Use the wrench to tighten the nozzle a little bit to the helium tank.
2. Turn on the red lever on the regulator slowly and fill the balloon with 20 cu. ft. of helium – just add this amount to whatever value is present on the regulator.
3. Tie the balloon using 2 cable ties. One to tie the balloon off the helium, and another to tie the balloon to the radiosonde hook. Careful that you do not puncture a hole in the process.
4. Double check that the Vaisala software is tracking the radiosonde prior to launch.
5. Launch, making sure that your fingers are away from the spool hook.
6. Once launched, check that MW41 sounding program detected the launch and is receiving data.
7. Go to the desktop and enter metadata in the spreadsheet.
8. If the balloon bursts below 500 hPa, launch another balloon.

When the sounding is complete:

• Close-out program and restart by clicking “terminate sounding” button.
• Initialize a new launch by putting a second radiosonde on the Vaisala ground check platform.
• Be sure to choose a frequency different from the one used in the first launch.