2019/4b.plaintext

   1 apollo xi post flight analysis spacecraft reentry trajectory review this document contains
   2 information about the events during there entry phase of apollo xiith as been compiled to satisfy
   3 flight planning safety requirements the review covers the following mission phase trans earth coast
   4 which ends with reentry into the mid pacific recovery area the original flightplan called for
   5 separation of the cm from the sm twelve minutes before entry interface successful separation would
   6 then trigger a sequence of burns intended to stabilise the service module and to move it out of
   7 there entry corridor to avoid debris collisions with the command module during there entry phase the
   8 reaction control system burn sequence involved both the roll and the minus x jets the attitude burns
   9 were intended to setup a rollin order to stabilise remaining fuel and to prevent uncontrolled
  10 gyration during the boost that would have then taken the sm out of there entry corridor into a high
  11 altitude orbit that would decay only after the command module had landed in the event the sequence
  12 of burns did not achieve the required trajectory shift with reports from the astronauts onboard and
  13 from a commercial airline pilot that the two space vehicles reentered the atmosphere together with
  14 the cm passing the sm during the plasma burn phase given the proximity of the vehicles during
  15 reentry it is considered highly fortunate that no debris from the relatively unprotected sms truck
  16 the cm and simulations show that such a strike would have been likely to cause catastrophic damage
  17 to the cm possible defects arising from a collision include i heatshield damage even a minor crack
  18 in one of the heatshield panels would be likely to cause super heating which could breach the hull
  19 leading to further catastrophic damage to the vehicle with probable loss of life ii premature firing
  20 of the parachute pyrotechnics leading to full or partial loss of the descent arrest system and loss
  21 of life iii damage to the parachute shield might have prevented the pyrotechnics from releasing the
  22 parachutes leading to a catastrophic collision on landing and loss of life iv damage to one or more
  23 of the parachutes could have led to a high velocity impact with probable resulting injuries and
  24 possible loss of life the high likelihood of catastrophic failure arising from the deviation from
  25 flight parameters means that further analysis of the separation burn strategy is required pending
  26 that remediation for the apollo xii reentry trajectory is a high priority it is suggested that
  27 surplus fuel should be ejected from the sm before the separation burn begins in order to stabilise
  28 the attitude and that the minus x burns should be timed to coincide with the roll jets to improve
  29 stability