You can find more details here: devzone.nordicsemi.com/blogs/1048/nrf52-rocket-part-i-introduction-to-model-rocketry/

The rocket is BLE enabled in the sense that it can be launched via BLE commands on a smartphone, and the onboard altimeter also sends real-time data to the smartphone via BLE while in flight. I've also made it so that it stores the altimeter data in RAM during flight and it can be read back via a BLE characteristic once it returns to ground, just in case of signal loss during its flight. I'm using the nRF52 because that's the newest and most powerful chip by Nordic when I was an intern there :).