Editing Hubble Space Telescope (section)

=== Key projects ===
In the early 1980s, NASA and STScI convened four panels to discuss key projects. These were projects that were both scientifically important and would require significant telescope time, which would be explicitly dedicated to each project. This guaranteed that these particular projects would be completed early, in case the telescope failed sooner than expected. The panels identified three such projects: 1) a study of the nearby intergalactic medium using quasar [[absorption line]]s to determine the properties of the [[intergalactic medium]] and the gaseous content of galaxies and groups of galaxies;<ref>{{cite journal |last1=Bahcall |first1=J. N. |last2=Bergeron |first2=J. |last3=Boksenberg |first3=A. |last4=Hartig |first4=G. F. |last5=Jannuzi |first5=B. T. |last6=Kirhakos |first6=S. |last7=Sargent |first7=W. L. W. |last8=Savage |first8=B. D. |last9=Schneider |first9=D. P. |display-authors=8 |date=1993 |title=The Hubble Space Telescope Quasar Absorption Line Key Project. I. First Observational Results, Including Lyman-Alpha and Lyman-Limit Systems |journal=The Astrophysical Journal Supplement Series |volume=87 |pages=1–43 |bibcode=1993ApJS...87....1B |doi=10.1086/191797 |doi-access=free}}</ref> 2) a medium deep survey using the Wide Field Camera to take data whenever one of the other instruments was being used<ref>{{cite journal |last1=Ostrander |first1=E. J. |last2=Nichol |first2=R. C. |last3=Ratnatunga |first3=K. U. |author-link3=Kavan Ratnatunga |last4=Griffiths |first4=R. E. |date=1998 |title=The Hubble Space Telescope Medium Deep Survey Cluster Sample: Methodology and Data |journal=The Astronomical Journal |volume=116 |issue=6 |pages=2644–2658 |arxiv=astro-ph/9808304 |bibcode=1998AJ....116.2644O |doi=10.1086/300627 |s2cid=11338445}}</ref> and 3) a project to determine the [[Hubble constant]] within ten percent by reducing the errors, both external and internal, in the calibration of the distance scale.<ref>{{cite web <!-- comments to stop bot from finding doi -->|url=https://www.cfa.harvard.edu/~huchra/hubble/ |title=The Hubble Constant |access-date=January 11, 2011 |author-link1=John Huchra |last=Huchra |first=John |year=2008| volume = <!-- -->| issue = <!-- --> |journal= <!-- --> |pages=<!-- --> |doi = <!-- --> |pmid=<!-- --> |pmc= <!-- --> |s2cid=<!-- -->}}</ref>