Chapter 4: Designing a Phase I WFC3 Proposal 4.1 Phase I and Phase II Proposals 4.2 Preparing a Phase I Proposal 4.2.1 Which WFC3 Channel(s) and Filter(s)? 4.2.2 What Exposure Times? 4.2.3 What Aperture or Subarray? 4.2.4 What Overheads and How Many HST Orbits? 4.2.5 Any Special Calibration Observations? 4.2.6 What is the Total Orbit Request?