These would normally be the angles to which the nozzle of the descent engine would be aimed to place its thrust axis through the stack's estimated centre of mass.Ĭonventionally, a return-to-Earth PAD would be for the CSM and it would include information pertaining to re-entry. Procedures for a lunar landing allowed the spacecraft to yaw around the thrust axis as required for operational reasons.Ĭhange in velocity for the AGS (Noun 86), fps (m/s): x, +820.3 (+) y, -20.0 (-) z, -215.0 (-). Unlike a CSM PAD, yaw is not stated for the LM. The desired spacecraft attitude is measured relative to the alignment of the guidance platform and is therefore set using the FDAI display in its inertial mode. Spacecraft attitude: Roll, 274° Pitch, 82°. This is the total resultant change in velocity the spacecraft would experience and is a vector sum of the three components given above.īurn duration or burn time: 4 minutes, 20 seconds. The perigee distance is so low, it will take the spacecraft well into Earth's atmosphere and thereby cause the spacecraft to re-enter.ĭelta-V R: 848.2 fps (258.53 m/s). H P, expected perigee of resulting orbit (Noun 42): 20.9 nautical miles (38.7 km). This burn is to place Apollo 13 on a Earth-bound trajectory, the apogee of which would be over 9999.9 nautical miles above the local body (the Moon), beyond the limit of the computer's display. H A, expected apogee of resulting orbit (Noun 42): Not applicable. The change in velocity is resolved into three components which are quoted relative to the LVLH (Local Vertical/Local Horizontal). Purpose: This PAD is for a burn of the LM's main engine two hours after pericynthion (their closest approach to the Moon) in order to return them to a specific place on Earth in this case the Mid-Pacific Landing site or MPL, and to do so faster than would have been the case with their current return trajectory.
0 Comments
Leave a Reply. |