Editing H-II Transfer Vehicle (section)

== Former evolutionary proposals ==
=== HTV-R ===
{{As of|2010}}, JAXA was planning to add a return capsule option. In this concept, HTV's pressurized cargo would be replaced by a reentry module capable of returning {{convert|1600|kg}} [[downmass|cargo]] from ISS to Earth.<ref>{{cite web|url=http://www.jaxa.jp/press/2010/08/20100811_sac_htv-r_j.html|title=回収機能付加型宇宙ステーション補給機（HTV-R）検討状況|publisher=JAXA|language=ja|date=August 11, 2010 |access-date=September 7, 2011|url-status=live|archive-url=https://web.archive.org/web/20100914081746/http://www.jaxa.jp/press/2010/08/20100811_sac_htv-r_j.html|archive-date=September 14, 2010}}</ref><ref>{{cite web |url=http://iss.jaxa.jp/htv-r/|title=回収機能付加型HTV(HTV-R)|language=ja|publisher=JAXA|access-date=September 7, 2011|url-status=dead |archive-url=https://web.archive.org/web/20110826205442/http://iss.jaxa.jp/htv-r/|archive-date=August 26, 2011 }}</ref>

Further, conceptual plans in 2012 included a follow-on spacecraft design by 2022 which would accommodate a crew of three and carry up to {{convert|400|kg}} of cargo.<ref>{{cite web |url=http://www.space.com/18198-japan-plans-manned-capsule-space-plane.html|title=Japan Wants Space Plane or Capsule by 2022|author=Rob Coppinger|publisher=Space.com|access-date=October 25, 2012|url-status=live |archive-url=https://web.archive.org/web/20151224020505/http://www.space.com/18198-japan-plans-manned-capsule-space-plane.html|archive-date=December 24, 2015}}</ref>

=== Lagrange outpost resupply ===
{{As of|2014}}, both JAXA and [[Mitsubishi Heavy Industries|Mitsubishi]] conducted studies of a next generation HTV as a possible Japanese contribution to the proposed [[Exploration Gateway Platform|international crewed outpost]] at [[Lagrangian point|Earth-Moon L2]].<ref name=jaxalunaraccess>{{cite web|url=http://www.nasa.gov/sites/default/files/files/04-Ueno_Lunar_Access_Architecture.pdf |title=International Human Lunar Mission Architecture / System and its Technologies|format=PDF|publisher=JAXA|date=2014-04-10|access-date=22 January 2015|url-status=live |archive-url=https://web.archive.org/web/20150415015209/http://www.nasa.gov/sites/default/files/files/04-Ueno_Lunar_Access_Architecture.pdf|archive-date=15 April 2015}} {{PD-notice}}</ref><ref>{{cite web |url=http://www.nasa.gov/sites/default/files/files/02-Hopkins-Intl-Industry-Perspective.pdf#page=13 |title=An International Industry Perspective on Extended Duration Missions Near the Moon |format=PDF |publisher=Lockheed Martin Corporation|date=2014-04-10|access-date=22 January 2015|url-status=live|archive-url=https://web.archive.org/web/20150415020947/http://www.nasa.gov/sites/default/files/files/02-Hopkins-Intl-Industry-Perspective.pdf#page=13|archive-date=15 April 2015}}</ref> This variant of HTV was to be launched by [[H3 (rocket)|H-X]] Heavy and can carry 1800&nbsp;kg of supplies to EML2.<ref name=jaxalunaraccess /> Modifications from the current HTV includes the addition of solar electric paddles and extension of the propellant tank.<ref name=jaxalunaraccess/>

=== Human-rated variant ===
A proposal announced in June 2008, "Preliminary Study for Manned Spacecraft with Escape System and H-IIB Rocket" suggested combining HTV's propulsion module with a [[Human-rating certification|human-rated]] capsule for four people.<ref name="ISTS_2008-g-14">{{cite web|author1=Takane Imada|author2=Michio Ito|author3=Shinichi Takata|date=June 2008|url=https://archive.ists.ne.jp/upload_pdf/2008-g-14.pdf |title=Preliminary Study for Manned Spacecraft with Escape System and H-IIB Rocket|format=PDF|publisher=26th ISTS|access-date=2010-12-25}}</ref>

=== Japanese space station ===
A Japanese space station has been proposed to be built up from HTV modules.<ref>{{cite web|url=https://archive.ists.or.jp/upload_pdf/2008-k-64.pdf|title=Development Plan for Future Mission from HTV System |last1=Sasaki|first1=Hiroshi|last2=Imada|first2=Takane|last3=Takata|first3=Shinichi|publisher=JAXA|date=2008|access-date=2016-07-19}}</ref> This method is similar to how the modules in ''[[Mir]]'', as well as many modules of the [[Russian Orbital Segment]] of the [[International Space Station|ISS]] are based on the [[TKS (spacecraft)|TKS]] cargo vehicle design.{{citation needed|date=December 2016}}