As space observatories become large

As space observatories become larger and more complex, the need for Program flexibility, cost-control options, andextended mission operations become increasingly important. Spacecraft modularity and on-orbit servicing technologiesand capabilities – which are defined and examined in more depth below – can help program managers overcome thesechallenges throughout both the prelaunch and on-orbit phases of the program. Historical missions such as Solar Max, theHubble Space Telescope (HST), and the ongoing maintenance of the International Space Station have demonstrated thevalue of modularity and servicing. Observatory programs today are also adding servicing to their core requirements,which will continue this advancement. The ATLAST observatory will be in a position to significantly benefit from thesetechnologies as it enters its design phase