I was a contractor for an agency under the DoD charged with maintaining/improving the military electronic health record. Many people equated “mission critical” issues as those affecting either the cost, schedule or performance of a project. For example, not obtaining a piece of GFI/GFE on time for our developers to implement was considered “mission critical” and was maintained in our risk management system.
Not sure about travel after the sequestration, but the agenda items for the proposed travel were most important. The on-site tasks of the proposed travelers had to directly link to progression of the project.