Get a FTDI USB to TTL Serial 3.3v adapter on Sparkfun and use Male to Male jumpers. The amazon small $5 ones are breaking down and having driver issues, the one I got years ago was a real FTDI chip and now on AmaZon they are not anymore. Spark Fun: https://www.sparkfun.com/products/9873
You will have to map the wires/jumpers between the two by reading the owners manual pinout on the StratoLogger pin out. You do not connect V+ between them, only the data lines. Your Altimeter will be powered by it's battery and your USB/TTL powered by the USB.