Editing Hubble Space Telescope (section)

=== Impact on aerospace engineering ===
In addition to its scientific results, Hubble has also made significant contributions to [[aerospace engineering]], in particular the performance of systems in low Earth orbit (LEO). These insights result from Hubble's long lifetime on orbit, extensive instrumentation, and return of assemblies to the Earth where they can be studied in detail. In particular, Hubble has contributed to studies of the behavior of [[Carbon fiber reinforced polymer|graphite composite]] structures in vacuum, optical contamination from residual gas and human servicing, [[radiation damage]] to electronics and sensors, and the long term behavior of [[multi-layer insulation]].<ref>{{cite journal |title=Experience with the Hubble Space Telescope: 20 years of an archetype |journal=Optical Engineering |first=Matthew D. |last=Lallo |volume=51 |issue=1 |at=011011 |date=January 2012 |doi=10.1117/1.OE.51.1.011011 |bibcode=2012OptEn..51a1011L |arxiv=1203.0002|s2cid=15722152 }}</ref> One lesson learned was that gyroscopes assembled using pressurized oxygen to deliver suspension fluid were prone to failure due to electric wire corrosion. Gyroscopes are now assembled using pressurized nitrogen.<ref name="Gyros" /> Another is that optical surfaces in LEO can have surprisingly long lifetimes; Hubble was only expected to last 15 years before the mirror became unusable, but after 14 years there was no measureable degradation.<ref name=NAS2005/> Finally, Hubble servicing missions, particularly those that serviced components not designed for in-space maintenance, have contributed towards the development of new tools and techniques for on-orbit repair.<ref>{{cite web |url=https://www.nasa.gov/mission_pages/hubble/servicing/SM4/main/SM4_Essentials.html |title=Servicing Mission 4 Essentials |publisher=NASA |date=September 15, 2008 |access-date=December 14, 2020 |archive-date=May 3, 2019 |archive-url=https://web.archive.org/web/20190503051034/https://www.nasa.gov/mission_pages/hubble/servicing/SM4/main/SM4_Essentials.html |url-status=live }}</ref>