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Originally posted by decisively
When the Command Module/Lunar module combined stack separates, when the lunar module is jettisoned, the command module capsule then continues traveling toward the earth at a velocity of greater magnitude than that of the just separated Command module/Lunar module stack, and even more importantly for our considerations here, that velocity vector will be of a DIFFERENT DIRECTION THAN THAT OF THE JUST SEPARATED COMMAND MODULE/LUNAR MODULE STACK..
Perhaps they had help?
The "Contact from Planet Koldas" tells of their encounter with Apollo 13 and guiding it back to Earth.
That was after popping Apollo's tank, because they could tell Apollo 13 had a nuclear bomb onboard to explode on the Moon.
Funny, I dont think Nasa ever sent another bomb back to the moon?
Tho they certainly rammed it with enough rockets.
C. LM Separation After CM IMU alignment was complete (140:55 GET) the spacecraft was maneuvered to the LM jettison attitude using the LM RCS. Once the maneuver was complete at 141:02 GET the spacecraft was placed in an AGS attitude hold with wide attitude error dead bands. The LM was maneuvered to an incorrect roll (LM body frame) attitude that placed the CM IMU platform near gimbal lock. The desired LM roll was 135 degrees but the spacecraft was maneuvered to 235 degrees LM roll. While the LM –X axis had been correctly aligned along the positive radius vector during the maneuver, the vehicle was yawed (CM body frame) 45 degrees on the north side of the CM entry ground track rather than 45 degrees on the south side (Figures 26, 27, and 28). By the time Mission Control had recognized the attitude error the CM and LM hatches were being installed by the crew. The minimum LM/CM separation was predicted to be 4,000 feet at EI. The initial CM roll angle after EI would steer the CM to the north, but subsequent modulation of the lift vector would move it away from the LM orbital plane. The in-plane separation of the vehicles was judged to be adequate for a nominal entry. The separation was not optimum if the crew flew a roll right (CM body frame) constant 4g entry due to PGNCS and EMS failures, but the separation was judged to be adequate. Due to these factors and the time-critical nature of the pre-entry timeline, Mission Control chose not to correct the spacecraft attitude before LM separation.15 The maneuver to the LM separation attitude was complicated by efforts to avoid CM platform gimbal lock. This required close coordination between the commander in the LM and the CM pilot in the CSM. The maneuver consumed a considerable amount of propellant. Had a gimbal lock occurred, a recovery procedure would have been executed to re-establish platform alignment before entry. Recovering from gimbal lock would have complicated the remaining part of the pre-EI timeline.25 The docking probe and drogue hardware, along with many other items, were left in the LM as a part of the stowage plan to achieve the desired CM L/D for re-entry. Before leaving the LM the crew placed the spacecraft in an AGS controlled attitude hold with wide attitude error deadbands.29 After the hatches were in place Mission Control closely monitored the CM IMU gimbal angles. If maintenance of the attitude hold by the LM AGS drove the CM IMU close to gimbal lock the crew would have performed the separation early. LM attitude control between hatch closure and separation was nominal and the CM IMU gimbal lock did not occur. The separation used delta-velocity, imparted from air venting, from the docking tunnel at separation. The CM RCS could not be used since CM RCS propellant was required for re-entry. Before undocking, the tunnel pressure was reduced to 2.2 psi to achieve the desired delta-velocity of ~2 feet/second. Apollo 10 (May 1969) LM jettison data was used to determine the appropriate docking tunnel pressure differential to achieve the desired deltavelocity. §
The LM was jettisoned 70 minutes before EI, 10 minutes earlier than planned, at 141:30 GET (Figure 29).
Sensed velocity at LM jettison was -0.65 feet/second along the LM X and -0.02 feet/second along the LM Y axis.
The separation was stable and the LM continued to be stable within the AGS 5 degree attitude error deadband until
LM loss-of-signal at 142:38 GET.
After separation, the crew maneuvered away from the near-gimbal lock attitude to the entry attitude. Entry attitude accuracy and IMU platform alignment were confirmed by a sextant star check. Tracking data showed a slight change in the EI flight path angle to -6.2 degrees. However, this was within expectations and did not require a change to the normal heads to Earth orientation of the CM at the start of re-entry to re-orient the lift vector.
The splash was on target, but the blackout was prolonged, NASA SAYS THEY DO NOT KNOW WHY. Could it be that LM/CM/Service module separation might account for this ? Could separation have imparted a trajectory change sufficient to account for the blackout ? Since the blackout was prolonged, that suggests the trajectory was shallow, more glancing. Might that explain things ?
Originally posted by decisively
Lunar Module Jettisoning was an ACTIVE EVENT
This is from NASA's own website;
Quote from the NASA site above(caps mine);
The lunar module is jettisoned BY FIRING SMALL CHARGES around the CSM docking ring.
That says it all right there. The CM and Aquarius were blown away from one another via an ACTIVE mechanism, the firing of charges. The CM's attitude, angular and linear momenta, would thereby all be changed and so affect the trajectory of this very same CM, its angle of attack, and its orientation/attitude coming in.edit on 3-7-2012 by decisively because: is> wasedit on 3-7-2012 by decisively because: added "(caps mine)"edit on 3-7-2012 by decisively because: removed "by small charges"edit on 3-7-2012 by decisively because: momentum> momenta, comma, added "this very same"
The actual undocking imparted far less velocity than that. The undocking was designed to impart 0.4 ft/s in separation velocity between the LM and CSM. Of course, that velocity relative to the existing flight path was proportionally distributed between the LM and CM based on their masses. Which means the undocking added about a whopping 0.27 ft/s to the velocity of the CM.
Originally posted by eriktheawful
Not the LM sep. Separation of the LM was achieved with 2.2 PSI of air in the docking ring. This gave a delta V of 2 feet per second between the LM and the CM.
2 feet per second of delta V is not enough to prolong the flight path. However being 6 degrees off in attitude is.
The separation used delta-velocity, imparted from air venting, from the docking tunnel at separation. The CM RCS could not be used since CM RCS propellant was required for re-entry. Before undocking, the tunnel pressure was reduced to 2.2 psi to achieve the desired delta-velocity of ~2 feet/second. Apollo 10 (May 1969) LM jettison data was used to determine the appropriate docking tunnel pressure differential to achieve the desired deltavelocity.
Originally posted by decisively
I agreereply to post by mbkennel
But I keep playing with this, that, and the other thing. I like physics a lot. Do you ?
I have lots of formal training as a chemist, but in terms of playing with problems, I like physics more. There are a few other pure physics problems that have come up for me studying Apollo.
Originally posted by intrptr
That is the question. How could the blackout be longer than expected and yet the landing on target?
I remember watching the whole thing live as a young child. My dad explained to me that if we didn't hear from them at the expected time that it meant something was wrong and they may have burned up in the atmosphere. Time ticked away and I thought oh no...
...and then the camera (suddenly) showed a shot of chutes deploying on a successful on target reentry of the capsule. To this day, I wonder about that. How did the camera cut to the chutes popping open at such a low altitude? That should have occurred much higher up?
If the capsule burned up and they had a standby aboard a helo ready to deploy for the camera, that would explain the late chute and on target splash down.
Weird thing is I had a friend whose dad was in the air force told me he saw a chopper carrying a helo suspended from it traveling the area prior to the splashdown. I have no confirmation of this, just a long time ago friendship and report.
I have not found a detailed explanation as to why the blackout was abnormally long. It might have been low transmit-power on the spacecraft. It might have been that the Apollo Range Instrumentation Aircraft (ARIA - modified 707s) that relayed comms from the spacecraft to Mission Control (MCC) were pointed the wrong way (while circling) for their antennae to receive the first signals. Perhaps the crew just waited until they heard the call from CapCom before they answered.
At this point, the Apollo capsule was generating aerodynamic lift (it really was an honest-to-god "flying saucer" - even if it was only gliding) and Command Module Pilot (CMP) Jack Swigert was flying it towards the recovery target area.
Nope. The main chutes deployed ~40 seconds after the drogues - at around 10,000 feet. That's less than 2 miles up, and 5-6 miles away from the recovery ship, so Odyssey would have been seen popping its mains ~20 degrees above the horizon as seen from Iwo Jima. Mind you, the TV cameramen were already looking towards the target area, so they very quickly acquired the capsule.
I'd like to know how it was reported at the time.