Editing Space Shuttle Enterprise (section)

===Approach and landing tests (ALT)===
{{Main|Approach and Landing Tests}}
[[File:HaiseandFullertonEnterprise.jpg|thumb|[[Fred Haise]] and [[Gordon Fullerton]] (wearing oxygen mask) in ''Enterprise''{{'s}} cockpit, 1977]]

On January 31, 1977, ''Enterprise'' was taken by road to [[Dryden Flight Research Center]] at [[Edwards Air Force Base]] to begin operational testing.<ref name="tech"/><ref name="basics">{{cite web |url=http://spaceflight.nasa.gov/shuttle/reference/basics/ |title=Space Shuttle Basics |work=NASA.gov |first=Kim |last=Dismukes |date=February 15, 2005 |access-date=November 28, 2007 |archive-date=November 27, 2007 |archive-url=https://web.archive.org/web/20071127050452/http://spaceflight.nasa.gov/shuttle/reference/basics/ |url-status=dead}}</ref>

While at NASA Dryden ''Enterprise'' was used by NASA for a variety of ground and flight tests intended to validate aspects of the shuttle program.<ref name="alt">{{cite web |url=http://www.dfrc.nasa.gov/Gallery/Photo/ALT/HTML/ |title=Space Shuttle Approach and Landing Tests (ALT) |work=NASA.gov |access-date=November 28, 2007 |archive-date=March 15, 2008 |archive-url=https://web.archive.org/web/20080315180758/http://www.dfrc.nasa.gov/Gallery/Photo/ALT/HTML/ |url-status=dead}}</ref> The initial nine-month testing period was referred to by the acronym ''ALT'', for "Approach and Landing Test".<ref name="tech"/><ref name="ff">{{cite web |url=http://grin.hq.nasa.gov/ABSTRACTS/GPN-2000-000218.html |title=Shuttle Enterprise Free Flight |work=NASA.gov |year=2000 |access-date=November 28, 2007 |url-status=dead |archive-url=https://web.archive.org/web/20130307094536/http://grin.hq.nasa.gov/ABSTRACTS/GPN-2000-000218.html |archive-date=March 7, 2013}}</ref> These tests included a maiden "flight" on February 18, 1977, atop a [[Boeing 747]] [[Shuttle Carrier Aircraft]] (SCA) to measure structural loads and ground handling and braking characteristics of the mated system. Ground tests of all orbiter subsystems were carried out to verify functionality prior to atmospheric flight.<ref name="nasasf20120427"/>

The mated ''Enterprise''/SCA combination was then subjected to five test flights with ''Enterprise'' uncrewed and unactivated. The purpose of these test flights was to measure the flight characteristics of the mated combination. These tests were followed with three test flights with ''Enterprise'' crewed to test the shuttle flight control systems.<ref name="tech"/>

On August 12, 1977, ''Enterprise'' flew on its own for the first time.<ref name="Futz1977">{{cite web |url=http://www.upi.com/Audio/Year_in_Review/Events-of-1977/Space-Shuttle-Enterprise/12361881614363-5/ |title=1977 Year in Review: Space Shuttle Enterprise |work=UPI.com |publisher=United Press International |first=Bob |last=Futz |year=1977 |access-date=January 9, 2013 |archive-date=January 5, 2013 |archive-url=https://web.archive.org/web/20130105184202/http://www.upi.com/Audio/Year_in_Review/Events-of-1977/Space-Shuttle-Enterprise/12361881614363-5/ |url-status=live }}</ref> ''Enterprise'' underwent four more free flights where the craft separated from the SCA and was landed under astronaut control. These tests verified the flight characteristics of the orbiter design and were used to carry out several aerodynamic and weight configurations.<ref name="ff"/> The first three flights were flown with a tailcone placed at the end of ''Enterprise''{{'s}} aft fuselage, which reduced drag and turbulence when mated to the SCA. The final two flights saw the tailcone removed and mockup main engine nozzles installed. On the fifth and final glider flight, [[pilot-induced oscillation]] problems were revealed, which had to be addressed before the first orbital launch occurred.<ref name="alt"/>

[[File:Enterprise lifted.jpg|thumb|upright|A crane hoists ''Enterprise'' into the [[Saturn V Dynamic Test Stand|Dynamic Structural Test Facility]] to undergo dynamic testing in launch configuration.]]