The SOFIA telescope door is a "monumental effort" says L-3 Communications Integrated Systems's Don Gillespie who is coordinating the telescope door design and fabrication.The door will cover an open port cavity nearly one-quarter of the circumference of the SOFIA aircraft.

The 18-foot (arc length) by 13.5-foot wide curved upper door is part of a system intended to protect the SOFIA telescope at the beginning and end of each mission, as well as on the ground. During flight, it opens only when the plane has reached its observing altitude of 39,000 to 45,000 feet, and on the ground only when the telescope mirror needs to be removed for re-coating. Most of the system design is taking place at Ames, while testing and fabrication is centered at L-3 Communications Integrated Systems's facilities in Waco, Texas.