Possible Clues:

• One in landing-place is explorer
• Part of bridge - holding ace, take the lead
• Constant as Van Gogh, but not a trailblazer
• Be the first individual to enter landing-stage
• Cask full of oxygen always needed for spacecraft
• One is the first but never at last
• An explorer needing one in support
• Founder, as one punctures coastal feature
• Mole interrupted by a certain person arriving early
• The support one received as an innovator