Mass storage with nRF51?

[Sensors]

I have a project that requires a bluetooth central to be used to gather data from a HRM service, which shouldn't be too much of an issue. However, it also has to store this, and other local sensor data to some sort of storage device (perhaps microSD or Flash memory).

I want to be able to access this data from a PC or other device, but I'm not sure if the nRF51 or nRF52 has the ability to support a file system and act as a USB mass storage device. Would I need to use an additional part to make this possible? If so, what options do I have?

Thanks

[Sensors]

It's not a viable option to take the SD card out, it must be a self-contained unit. It's awkward, but necessary in this case.

Re-transmitting the data via BLE is potentially an option, but 1GB of data would take over two hours at BLE's 1Mbps.