The traditional model of mission operations is centralized with all activities taking place at a single location. The Multi-mission Encrypted Communication System (MECS) is a tool for enabling distributed operations where scientists and engineers at several locations collaborate over the Internet to perform mission operations activities. There are many reasons why distributed operations are desirable. Travel and facilities costs can be reduced. Disruption can also be reduced both at the mission operations facility which no longer has to house remote participants, and in the lives of remote participants who no longer have to leave their homes for weeks at a time. Finally, the level of participation can be increased leading to greater return from a mission. The MECS architecture is centered around maintaining cached file replicas in a consistent state on remote machines. Challenges that are addressed by NECS include security, compatibility with legacy applications, clients that disconnect and reconnect to the network frequently, and user interface issues involved in keeping users informed when files are created or modified. This paper discusses MECS' architecture for distributed operations and lessons learned from a field test in May 2001.