given mission. NFOs are not trained to pilot the aircraft, although they do train in some dual-control aircraft and are given the opportunity to practice "hands on controls" basic airmanship techniques. Some current and recently retired naval aircraft with side-by-side seating are also authorized to operate under dual-piloted weather minimums with one pilot and one NFO. However, in the unlikely event that the pilot of a single piloted naval aircraft becomes incapacitated, the crew would likely eject or bail out, if possible, as NFOs are not qualified to land the aircraft, especially in the carrier-based shipboard environment. NFOs serve as weapon systems officers (WSOs), electronic warfare officers (EWO), electronic countermeasures officers (ECMO), tactical coordinators (TACCO), bombardiers, and navigators. They can serve as aircraft mission commanders, although in accordance with the OPNAVINST 3710 series of instructions, the pilot in command, regardless of rank, is always responsible for the safe piloting of the aircraft. Many NFOs achieve flight/section lead, division lead, package lead, mission lead and mission commander qualification, even when the pilot of the aircraft does not have that designation. Often, a senior NFO is paired with a junior pilot (and vice versa). NFO astronauts have also flown aboard the Space Shuttle and the International Space Station as mission specialists and wear NFO-astronaut wings. Like their naval aviator counterparts, NFOs in both the Navy and Marine Corps have commanded aviation squadrons, carrier air wings, shore-based functional air wings and air groups, Marine aircraft groups, air facilities, air stations, aircraft carriers, amphibious assault ships, carrier strike groups, expeditionary strike groups, Marine aircraft wings, Marine expeditionary forces, numbered fleets, and component commands of unified combatant commands. Three NFOs have reached four-star rank, one as a Marine Corps general having served as the Assistant Commandant of the Marine Corps, and the other two as Navy admirals, one having served as Vice Chief of Naval Operations before commanding U.S. Fleet Forces Command & U.S. Atlantic Fleet, U.S. Pacific Command (USPACOM) and U.S. Central Command (USCENTCOM), and the other having commanded U.S. Pacific Command, having previously commanded U.S. Pacific Fleet. Another former NFO who retrained and qualified as a Naval Aviator also achieved four-star rank as a Marine Corps general, commanded U.S. Strategic Command (USSTRATCOM) and later served as Vice Chairman of the Joint Chiefs of Staff (VCJCS). In some quarters, NFO careers may be viewed more restrictive than their Naval Aviator (e.g., pilot) counterparts. For