Editing Spaceflight (section)

=== Transfer energy ===
The term "transfer energy" means the total amount of [[energy]] imparted by a rocket stage to its payload. This can be the energy imparted by a [[First stage (rocketry)|first stage]] of a [[launch vehicle]] to an upper stage plus payload, or by an upper stage or spacecraft [[Apogee kick motor|kick motor]] to a [[spacecraft]].<ref>{{cite book |author=Erickson |first=Lance K. |title=Space Flight: History, Technology, and Operations |publisher=Government Institutes |year=2010 |page=187}}</ref><ref>{{cite press release |title=Musk pre-launch backgrounder on Falcon 9 Flight 20 |url=http://www.spacex.com/news/2015/12/21/background-tonights-launch |date=22 December 2015 |access-date=28 December 2015 |publisher=SpaceX |archive-date=8 March 2017 |archive-url=https://web.archive.org/web/20170308172650/http://www.spacex.com/news/2015/12/21/background-tonights-launch |url-status=dead }}</ref>