The Orion spacecraft is designed to return astronauts to a landing within 10 km of the intended landing target from low Earth orbit, lunar direct-entry, and lunar skip-entry trajectories. Al pile the landing is nominally controlled autonomously, the crew can fly precision entries manually in the event of an anomaly. The onboard entry displays will be used by the crew to monitor and manually fly the entry, descent, and landing, while the Entry Monitor System (EMS) will be used to monitor the health and status of the onboard guidance and the trajectory. The entry displays are driven by the entry display feeder, part of the Entry Monitor System (EMS). The entry re-targeting module, also part of the EMS, provides all the data required to generate the capability footprint of the vehicle at any point in the trajectory, which is shown on the Primary Flight Display (PFD). It also provides caution and warning data and recommends the safest possible re-designated landing site when the nominal landing site is no longer within the capability of the vehicle. The PFD and the EMS allow the crew to manually fly an entry trajectory profile from entry interface until parachute deploy having the flexibility to manually steer the vehicle to a selected landing site that best satisfies the priorities of the crew. The entry display feeder provides data from the ENIS and other components of the GNC flight software to the displays at the proper rate and in the proper units. It also performs calculations that are specific to the entry displays and which are not made in any other component of the flight software. In some instances, it performs calculations identical to those performed by the onboard primary guidance algorithm to protect against a guidance system failure. These functions and the interactions between the entry display feeder and the other components of the EMS are described. Attitude IndicatorsThe PFD is shown in Figure 1. The PFD can be broken up into 3 main areas. The first area, shown in the blue outline, consists of spacecraft attitude indicators, attitude errors, bank angle queues. The Attitude Director Indicator (ADI) ball provides a 3D representation of the spacecraft attitude in a Local Vertical Local Horizontal (LVLH) reference frame. These attitudes are provided as Euler angles, which are converted within the entry display feeder, from a direction cosine matrix using a pitch, yaw, roll Euler sequence. The corresponding attitude rates and errors are shown on the graduated bar scale on the top, right, and bottom of the ADI ball. During entry, the crew can manually control the bank angle but not the pitch and yaw angles. Pitch and yaw forces are dominated by aerodynamics effects and cannot be significantly affected by thrusters during entry, so those channels are disabled. The current bank angle is displayed with the magenta airplane symbol, while the commanded bank angle is displayed with the green airplane symbol. The commanded bank angle is smoothed with a low-pass filter with a time constant of 0.2 seconds to pre...

Two piloted simulations were conducted at NASA's Johnson Space Center using the Cooper-Harper scale to study the handling qualities of the Orion Command Module capsule during atmospheric entry flight. The simulations were conducted using high fidelity 6-DOF simulators for Lunar Return Skip Entry and International Space Station Return Direct Entry flight using bank angle steering commands generated by either the Primary (PredGuid) or Backup (PLM) guidance algorithms. For both evaluations, manual control of bank angle began after descending through Entry Interface into the atmosphere until drogue chutes deployment. Pilots were able to use defined bank management and reversal criteria to accurately track the bank angle commands, and stay within flight performance metrics of landing accuracy, g-loads, and propellant consumption, suggesting that the pilotability of Orion under manual control is both achievable and provides adequate trajectory performance with acceptable levels of pilot effort. Another significant result of these analyses is the applicability of flying a complex entry task under high speed entry flight conditions relevant to the next generation Multi Purpose Crew Vehicle return from Mars and Near Earth Objects.1 Aerospace Engineer, Advanced Mission Design Branch, Mail Stop EG5; michael.a.tigges@nasa.gov