Mission Control was worried about a warning light that indicated that a heat shield was loose. What problem would a loose heat shield have caused for John Glenn?Without the heat shield, the retro-package's small rockets would not be held in place. Without the heat shield, the capsule would not slow down when it reentered Earth's atmosphere. Without the heat shield, Glenn would not be able to turn the capsule toward Earth for reentry. Without the heat shield, the capsule would not be able to survive the heat of reentry into Earth's atmosphere.