To open cell D-02-106 in Starfield during the "Echoes of the Past" mission, follow these steps:

1. Locate the cell block D-02-106. The cell door cannot be opened with a digipick or computer directly.
2. From the cell, turn right and follow the corridor, then take a left down a stairwell. You will pass by the showers and kitchen areas.
3. Near the kitchen, go up the stairs to reach the security room.
4. Inside the security room, find the release switch on the wall (next to a broken intercom). Press the Section 2 release switch to unlock all the cells in D-block, including D-02-106.
5. Return to cell D-02-106 and open the door to collect the loot inside, which includes weapons, ammo, mines, digipicks, and other useful items.

This process unlocks the cell without needing a computer or digipick on the door itself and is part of an optional but rewarding objective in the mission