▁( fr ust um ) ▁ ▁tall ▁with ▁a ▁diameter ▁of ▁ ▁across ▁the ▁base . ▁The ▁forward ▁compart ment ▁contained ▁two ▁reaction ▁control ▁engines , ▁the ▁dock ing ▁tunnel , ▁and ▁the ▁components ▁of ▁the ▁Earth ▁Land ing ▁System . ▁The ▁inner ▁pressure ▁vessel ▁hous ed ▁the ▁crew ▁accommod ation , ▁equipment ▁b ays , ▁controls ▁and ▁displays , ▁and ▁many ▁space craft ▁systems . ▁The ▁a ft ▁compart ment ▁contained ▁ 1 0 ▁reaction ▁control ▁engines ▁and ▁their ▁related ▁prop ell ant ▁t anks , ▁fresh ▁water ▁t anks , ▁and ▁the ▁C SM ▁um bil ical ▁c ables . ▁ ▁Const ruction ▁The ▁command ▁module ▁consisted ▁of ▁two ▁basic ▁structures ▁joined ▁together : ▁the ▁inner ▁structure ▁( press ure ▁shell ) ▁and ▁the ▁outer ▁structure . ▁ ▁The ▁inner ▁structure ▁was ▁an ▁al umin um ▁sand wich ▁construction ▁which ▁consisted ▁of ▁a ▁w eld ed ▁al umin um ▁inner ▁skin , ▁ad hes ively ▁bond ed ▁al umin um ▁h oney comb ▁core , ▁and ▁outer ▁face ▁sheet . ▁The ▁thick ness ▁of ▁the ▁h oney comb ▁varied ▁from ▁about ▁ ▁at ▁the ▁base ▁to ▁about ▁ ▁at ▁the ▁forward ▁access ▁tunnel . ▁This ▁inner ▁structure ▁was ▁the ▁press ur ized ▁crew ▁compart ment . ▁ ▁The ▁outer ▁structure ▁was ▁made ▁of ▁st ain less ▁steel ▁bra zed - h oney comb ▁bra zed ▁between ▁steel ▁al loy ▁face ▁sheets . ▁It ▁varied ▁in ▁thick ness ▁from ▁ 0 . 5 ▁in ch ▁to ▁ 2 . 5 ▁inches .