Editing Hard science fiction (section)

==Definition==
The heart of the "hard science fiction" designation is the relationship of the science content and attitude to the rest of the narrative, and (for some readers, at least) the "hardness" or rigor of the science itself.<ref name="samuelson1993">{{cite journal |last=Samuelson |first=David N. |date=July 1993 | title=Modes of Extrapolation: The Formulas of Hard Science Fiction | journal=Science Fiction Studies | volume=part 2 | issue=60 |series=20 | url=http://www.depauw.edu/sfs/abstracts/a60.htm | access-date=2007-10-07 }}</ref> One requirement for hard SF is procedural or intentional: a story should try to be accurate, logical, credible and rigorous in its use of current scientific and technical knowledge about which technology, phenomena, scenarios and situations that are practically or theoretically possible. For example, the development of concrete proposals for spaceships, space stations, space missions, and a [[Space Shuttle program|US space program]] in the 1950s and 1960s influenced a widespread proliferation of "hard" space stories.<ref name="westfahl993">{{cite journal |last=Westfahl |first=Gary |date=July 1993 |title= The Closely Reasoned Technological Story: The Critical History of Hard Science Fiction |journal=Science Fiction Studies |volume=20 |issue=2 |pages=141–142}}</ref> Later discoveries do not necessarily invalidate the label of hard SF, as evidenced by [[P. Schuyler Miller]], who called [[Arthur C. Clarke]]'s 1961 novel ''[[A Fall of Moondust]]'' hard SF,<ref name="jesse2005" /> and the designation remains valid even though a crucial plot element, the existence of deep pockets of "moondust" in lunar craters, is now known to be incorrect.

There is a degree of flexibility in how far from "real science" a story can stray before it becomes less of a hard SF.<ref name="Westfahl1993CloselyReasoned">{{cite journal |last=Westfahl |first=G. |date=July 1993 |title='The Closely Reasoned Technological Story': The Critical History of Hard Science Fiction |journal=Science Fiction Studies |volume=20 |issue=2 |pages=157–175 |jstor=4240246 |publisher=SF-TH Inc}}</ref> Hard science fiction authors only include more controversial devices when the ideas draw from well-known scientific and mathematical principles. In contrast, authors writing [[Soft science fiction|softer SF]] use such devices without a scientific basis (sometimes referred to as "enabling devices", since they allow the story to take place).<ref>{{cite web |last=Chiang |first=Ted |title=MIND MELD: The Tricky Trope of Time Travel |date=April 15, 2009 |url=http://www.sfsignal.com/archives/2009/04/mind-meld-time-travel/ |access-date=2009-04-28 |url-status=dead |archive-url=https://web.archive.org/web/20090422143721/http://www.sfsignal.com/archives/2009/04/mind-meld-time-travel/ |archive-date=April 22, 2009 |work=SF Signal}}</ref>

Readers of "hard SF" often try to find inaccuracies in stories. For example, a group at [[Massachusetts Institute of Technology|MIT]] concluded that the planet [[Mesklin]] in [[Hal Clement]]'s 1953 novel ''[[Mission of Gravity]]'' would have had a sharp edge at the equator, and a Florida high school class calculated that in [[Larry Niven]]'s 1970 novel ''[[Ringworld]]'' the topsoil would have slid into the seas in a few thousand years.<ref name="westfahl2008"/> Niven fixed these errors in his sequel ''[[The Ringworld Engineers]]'', and noted them in the [[foreword]].