In addition , an erroneous signal from a pad umbilical threw open the LOX boil - off valve at liftoff , causing a gradual decay in tank pressure during ascent .
This was a secondary signal that did not contribute to the eventual loss of the missile .
In addition , an erroneous signal from a pad umbilical threw open the LOX boil - off valve at liftoff , causing a gradual decay in tank pressure during ascent , although this was a secondary failure that did not contribute to the eventual loss of the missile .