Did the Apollo astronauts ever describe reentry deceleration?












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Did the Apollo astronauts describe any differences in how it felt in the CM as it passed between the hypersonic, supersonic, transonic and the subsonic zone? Did the CM shake more or less in different zones? Was the type of movements different through the descent?










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    Did the Apollo astronauts describe any differences in how it felt in the CM as it passed between the hypersonic, supersonic, transonic and the subsonic zone? Did the CM shake more or less in different zones? Was the type of movements different through the descent?










    share|improve this question



























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      Did the Apollo astronauts describe any differences in how it felt in the CM as it passed between the hypersonic, supersonic, transonic and the subsonic zone? Did the CM shake more or less in different zones? Was the type of movements different through the descent?










      share|improve this question















      Did the Apollo astronauts describe any differences in how it felt in the CM as it passed between the hypersonic, supersonic, transonic and the subsonic zone? Did the CM shake more or less in different zones? Was the type of movements different through the descent?







      apollo-program reentry astronauts






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      edited Dec 14 '18 at 13:39









      Machavity

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      asked Dec 14 '18 at 13:26









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          22














          The best sources for this kind of thing might be the technical crew debriefings done within days of each flight.



          I've looked at a few of them and they don't describe any shaking; they frequently comment on the smoothness of reentry, in fact. They do discuss (low-frequency) oscillations in a few cases, i.e. the capsule rocking back and forth due to aerodynamic effects.



          Apollo 11:




          ALDRIN I thought the g constant was quite smooth.



          COLLINS I thought it was smooth also.




          Aside: this debrief also includes a description of the appearance of the ionization trail which might bear on another question you had:




          COLLINS Along about .05g, we started to get all these colors past the windows; Buzz took some movies, which we looked at last night. They don't really show what the human
          eye sees. Around the edge of the plasma sheath, there are all varieties of colors- lavenders, lightish bluish greens, little touches of violet, and great variations mostly of blues and greens. The central core has variations on a orange-yellow theme. It's sort of
          a combination of all the colors of the rainbow really.




          Apollo 12:




          CONRAD Oscillations. I thought, boy, the spacecraft was steady as a rock. It's just like the simulator. I found that hard to believe and even made the comment I wanted to see whether the spacecraft was that steady and stable during reentry.



          GORDON It really is.



          CONRAD And it was just like the simulator. You get in the transonic region, and if you get it to oscillate a little bit, you get some more RCS firing.




          The Apollo 17 crew does mention noise:




          EVANS Communications - From 90 000 feet until about main parachute deployment, I had a time trying to hear Jack. There was a lot of background noise.



          EVANS It just gets noisy in the spacecraft from about 90 000 feet on down. Once you get the altimeter off the peg, I had a time hearing you call out.



          SCHMITT I was shouting, too. I realized you were having trouble hearing. There was noise. It must have been air noise coming through the hull.







          share|improve this answer



















          • 1




            Are there any deceleration measurement graphs available? But telemetry might have been discontinued during the hot phase of reentry. Data recording within the command module was very limited at that time.
            – Uwe
            Dec 14 '18 at 16:36










          • I assume so; the data recorder in the CM was adequate.
            – Russell Borogove
            Dec 14 '18 at 16:39










          • Here's one, surprisingly a multiple-peak affair from Apollo 10: history.nasa.gov/SP-368/p135b.htm -- doesn't look like raw data though.
            – Russell Borogove
            Dec 14 '18 at 16:46












          • I'm interested in how many g's they felt. Related to my question what's max Q for re-entry.
            – HopDavid
            Dec 14 '18 at 17:20










          • @HopDavid Peak about 6.5-7g. space.stackexchange.com/a/7857/195
            – Russell Borogove
            Dec 14 '18 at 17:41













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          22














          The best sources for this kind of thing might be the technical crew debriefings done within days of each flight.



          I've looked at a few of them and they don't describe any shaking; they frequently comment on the smoothness of reentry, in fact. They do discuss (low-frequency) oscillations in a few cases, i.e. the capsule rocking back and forth due to aerodynamic effects.



          Apollo 11:




          ALDRIN I thought the g constant was quite smooth.



          COLLINS I thought it was smooth also.




          Aside: this debrief also includes a description of the appearance of the ionization trail which might bear on another question you had:




          COLLINS Along about .05g, we started to get all these colors past the windows; Buzz took some movies, which we looked at last night. They don't really show what the human
          eye sees. Around the edge of the plasma sheath, there are all varieties of colors- lavenders, lightish bluish greens, little touches of violet, and great variations mostly of blues and greens. The central core has variations on a orange-yellow theme. It's sort of
          a combination of all the colors of the rainbow really.




          Apollo 12:




          CONRAD Oscillations. I thought, boy, the spacecraft was steady as a rock. It's just like the simulator. I found that hard to believe and even made the comment I wanted to see whether the spacecraft was that steady and stable during reentry.



          GORDON It really is.



          CONRAD And it was just like the simulator. You get in the transonic region, and if you get it to oscillate a little bit, you get some more RCS firing.




          The Apollo 17 crew does mention noise:




          EVANS Communications - From 90 000 feet until about main parachute deployment, I had a time trying to hear Jack. There was a lot of background noise.



          EVANS It just gets noisy in the spacecraft from about 90 000 feet on down. Once you get the altimeter off the peg, I had a time hearing you call out.



          SCHMITT I was shouting, too. I realized you were having trouble hearing. There was noise. It must have been air noise coming through the hull.







          share|improve this answer



















          • 1




            Are there any deceleration measurement graphs available? But telemetry might have been discontinued during the hot phase of reentry. Data recording within the command module was very limited at that time.
            – Uwe
            Dec 14 '18 at 16:36










          • I assume so; the data recorder in the CM was adequate.
            – Russell Borogove
            Dec 14 '18 at 16:39










          • Here's one, surprisingly a multiple-peak affair from Apollo 10: history.nasa.gov/SP-368/p135b.htm -- doesn't look like raw data though.
            – Russell Borogove
            Dec 14 '18 at 16:46












          • I'm interested in how many g's they felt. Related to my question what's max Q for re-entry.
            – HopDavid
            Dec 14 '18 at 17:20










          • @HopDavid Peak about 6.5-7g. space.stackexchange.com/a/7857/195
            – Russell Borogove
            Dec 14 '18 at 17:41


















          22














          The best sources for this kind of thing might be the technical crew debriefings done within days of each flight.



          I've looked at a few of them and they don't describe any shaking; they frequently comment on the smoothness of reentry, in fact. They do discuss (low-frequency) oscillations in a few cases, i.e. the capsule rocking back and forth due to aerodynamic effects.



          Apollo 11:




          ALDRIN I thought the g constant was quite smooth.



          COLLINS I thought it was smooth also.




          Aside: this debrief also includes a description of the appearance of the ionization trail which might bear on another question you had:




          COLLINS Along about .05g, we started to get all these colors past the windows; Buzz took some movies, which we looked at last night. They don't really show what the human
          eye sees. Around the edge of the plasma sheath, there are all varieties of colors- lavenders, lightish bluish greens, little touches of violet, and great variations mostly of blues and greens. The central core has variations on a orange-yellow theme. It's sort of
          a combination of all the colors of the rainbow really.




          Apollo 12:




          CONRAD Oscillations. I thought, boy, the spacecraft was steady as a rock. It's just like the simulator. I found that hard to believe and even made the comment I wanted to see whether the spacecraft was that steady and stable during reentry.



          GORDON It really is.



          CONRAD And it was just like the simulator. You get in the transonic region, and if you get it to oscillate a little bit, you get some more RCS firing.




          The Apollo 17 crew does mention noise:




          EVANS Communications - From 90 000 feet until about main parachute deployment, I had a time trying to hear Jack. There was a lot of background noise.



          EVANS It just gets noisy in the spacecraft from about 90 000 feet on down. Once you get the altimeter off the peg, I had a time hearing you call out.



          SCHMITT I was shouting, too. I realized you were having trouble hearing. There was noise. It must have been air noise coming through the hull.







          share|improve this answer



















          • 1




            Are there any deceleration measurement graphs available? But telemetry might have been discontinued during the hot phase of reentry. Data recording within the command module was very limited at that time.
            – Uwe
            Dec 14 '18 at 16:36










          • I assume so; the data recorder in the CM was adequate.
            – Russell Borogove
            Dec 14 '18 at 16:39










          • Here's one, surprisingly a multiple-peak affair from Apollo 10: history.nasa.gov/SP-368/p135b.htm -- doesn't look like raw data though.
            – Russell Borogove
            Dec 14 '18 at 16:46












          • I'm interested in how many g's they felt. Related to my question what's max Q for re-entry.
            – HopDavid
            Dec 14 '18 at 17:20










          • @HopDavid Peak about 6.5-7g. space.stackexchange.com/a/7857/195
            – Russell Borogove
            Dec 14 '18 at 17:41
















          22












          22








          22






          The best sources for this kind of thing might be the technical crew debriefings done within days of each flight.



          I've looked at a few of them and they don't describe any shaking; they frequently comment on the smoothness of reentry, in fact. They do discuss (low-frequency) oscillations in a few cases, i.e. the capsule rocking back and forth due to aerodynamic effects.



          Apollo 11:




          ALDRIN I thought the g constant was quite smooth.



          COLLINS I thought it was smooth also.




          Aside: this debrief also includes a description of the appearance of the ionization trail which might bear on another question you had:




          COLLINS Along about .05g, we started to get all these colors past the windows; Buzz took some movies, which we looked at last night. They don't really show what the human
          eye sees. Around the edge of the plasma sheath, there are all varieties of colors- lavenders, lightish bluish greens, little touches of violet, and great variations mostly of blues and greens. The central core has variations on a orange-yellow theme. It's sort of
          a combination of all the colors of the rainbow really.




          Apollo 12:




          CONRAD Oscillations. I thought, boy, the spacecraft was steady as a rock. It's just like the simulator. I found that hard to believe and even made the comment I wanted to see whether the spacecraft was that steady and stable during reentry.



          GORDON It really is.



          CONRAD And it was just like the simulator. You get in the transonic region, and if you get it to oscillate a little bit, you get some more RCS firing.




          The Apollo 17 crew does mention noise:




          EVANS Communications - From 90 000 feet until about main parachute deployment, I had a time trying to hear Jack. There was a lot of background noise.



          EVANS It just gets noisy in the spacecraft from about 90 000 feet on down. Once you get the altimeter off the peg, I had a time hearing you call out.



          SCHMITT I was shouting, too. I realized you were having trouble hearing. There was noise. It must have been air noise coming through the hull.







          share|improve this answer














          The best sources for this kind of thing might be the technical crew debriefings done within days of each flight.



          I've looked at a few of them and they don't describe any shaking; they frequently comment on the smoothness of reentry, in fact. They do discuss (low-frequency) oscillations in a few cases, i.e. the capsule rocking back and forth due to aerodynamic effects.



          Apollo 11:




          ALDRIN I thought the g constant was quite smooth.



          COLLINS I thought it was smooth also.




          Aside: this debrief also includes a description of the appearance of the ionization trail which might bear on another question you had:




          COLLINS Along about .05g, we started to get all these colors past the windows; Buzz took some movies, which we looked at last night. They don't really show what the human
          eye sees. Around the edge of the plasma sheath, there are all varieties of colors- lavenders, lightish bluish greens, little touches of violet, and great variations mostly of blues and greens. The central core has variations on a orange-yellow theme. It's sort of
          a combination of all the colors of the rainbow really.




          Apollo 12:




          CONRAD Oscillations. I thought, boy, the spacecraft was steady as a rock. It's just like the simulator. I found that hard to believe and even made the comment I wanted to see whether the spacecraft was that steady and stable during reentry.



          GORDON It really is.



          CONRAD And it was just like the simulator. You get in the transonic region, and if you get it to oscillate a little bit, you get some more RCS firing.




          The Apollo 17 crew does mention noise:




          EVANS Communications - From 90 000 feet until about main parachute deployment, I had a time trying to hear Jack. There was a lot of background noise.



          EVANS It just gets noisy in the spacecraft from about 90 000 feet on down. Once you get the altimeter off the peg, I had a time hearing you call out.



          SCHMITT I was shouting, too. I realized you were having trouble hearing. There was noise. It must have been air noise coming through the hull.








          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Dec 14 '18 at 16:41

























          answered Dec 14 '18 at 16:25









          Russell BorogoveRussell Borogove

          83.4k2281360




          83.4k2281360








          • 1




            Are there any deceleration measurement graphs available? But telemetry might have been discontinued during the hot phase of reentry. Data recording within the command module was very limited at that time.
            – Uwe
            Dec 14 '18 at 16:36










          • I assume so; the data recorder in the CM was adequate.
            – Russell Borogove
            Dec 14 '18 at 16:39










          • Here's one, surprisingly a multiple-peak affair from Apollo 10: history.nasa.gov/SP-368/p135b.htm -- doesn't look like raw data though.
            – Russell Borogove
            Dec 14 '18 at 16:46












          • I'm interested in how many g's they felt. Related to my question what's max Q for re-entry.
            – HopDavid
            Dec 14 '18 at 17:20










          • @HopDavid Peak about 6.5-7g. space.stackexchange.com/a/7857/195
            – Russell Borogove
            Dec 14 '18 at 17:41
















          • 1




            Are there any deceleration measurement graphs available? But telemetry might have been discontinued during the hot phase of reentry. Data recording within the command module was very limited at that time.
            – Uwe
            Dec 14 '18 at 16:36










          • I assume so; the data recorder in the CM was adequate.
            – Russell Borogove
            Dec 14 '18 at 16:39










          • Here's one, surprisingly a multiple-peak affair from Apollo 10: history.nasa.gov/SP-368/p135b.htm -- doesn't look like raw data though.
            – Russell Borogove
            Dec 14 '18 at 16:46












          • I'm interested in how many g's they felt. Related to my question what's max Q for re-entry.
            – HopDavid
            Dec 14 '18 at 17:20










          • @HopDavid Peak about 6.5-7g. space.stackexchange.com/a/7857/195
            – Russell Borogove
            Dec 14 '18 at 17:41










          1




          1




          Are there any deceleration measurement graphs available? But telemetry might have been discontinued during the hot phase of reentry. Data recording within the command module was very limited at that time.
          – Uwe
          Dec 14 '18 at 16:36




          Are there any deceleration measurement graphs available? But telemetry might have been discontinued during the hot phase of reentry. Data recording within the command module was very limited at that time.
          – Uwe
          Dec 14 '18 at 16:36












          I assume so; the data recorder in the CM was adequate.
          – Russell Borogove
          Dec 14 '18 at 16:39




          I assume so; the data recorder in the CM was adequate.
          – Russell Borogove
          Dec 14 '18 at 16:39












          Here's one, surprisingly a multiple-peak affair from Apollo 10: history.nasa.gov/SP-368/p135b.htm -- doesn't look like raw data though.
          – Russell Borogove
          Dec 14 '18 at 16:46






          Here's one, surprisingly a multiple-peak affair from Apollo 10: history.nasa.gov/SP-368/p135b.htm -- doesn't look like raw data though.
          – Russell Borogove
          Dec 14 '18 at 16:46














          I'm interested in how many g's they felt. Related to my question what's max Q for re-entry.
          – HopDavid
          Dec 14 '18 at 17:20




          I'm interested in how many g's they felt. Related to my question what's max Q for re-entry.
          – HopDavid
          Dec 14 '18 at 17:20












          @HopDavid Peak about 6.5-7g. space.stackexchange.com/a/7857/195
          – Russell Borogove
          Dec 14 '18 at 17:41






          @HopDavid Peak about 6.5-7g. space.stackexchange.com/a/7857/195
          – Russell Borogove
          Dec 14 '18 at 17:41




















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