Stratospehric observatories

The stratospheric observatories have advantages that are similar to the space observatories over the ground-based ones, because they operate above the main part of the atmosphere. Since they are placed in balloons or in airplanes, their instruments can be frequently repaired and renovated at a much lower cost than those of the space observatories. The most popular stratospheric observatory is SOFIA (Stratospheric Observatory For Infrared Astronomy), which is mounted on a Boeing 747 airplane and operates at a height of 12 km.

An example of a stratospheric observatory is shown in Attachment 3.