View source for H-I

{{for|the molecule with molecular formula H-I|hydrogen iodide}}
{{short description|Japanese liquid-fuelled carrier rocket}}
{{Infobox Rocket
|image         = H-I.svg
|caption       = H-I rocket
|function      = [[Medium-lift launch vehicle]]
|manufacturer  = {{Indented plainlist|
* [[Mitsubishi Heavy Industries]] (production)
* [[McDonnell Douglas]] (design)
}}
|country-origin= {{Indented plainlist|
* Japan (production)
* United States (design)
}}
|height        = {{cvt|42|m}}
|diameter      = {{cvt|2.44|m}}
|mass          = {{cvt|142260|kg}}
|stages        = 2 or 3
|capacities    = 
{{Infobox Rocket/Payload
|location      = [[Low Earth orbit|LEO]]
|mass          = {{cvt|3200|kg}}
}}
{{Infobox Rocket/Payload
|location      = [[Geosynchronous transfer orbit|GTO]]
|mass          = {{cvt|1100|kg}}
}}
|family        = [[Thor (rocket)|Thor]]
|comparable    = [[Delta 3000]], [[PSLV]]
|status        = Retired
|sites         = [[Tanegashima Space Center|Tanegashima]], [[Osaki Launch Complex|Osaki]]
|launches      = 9
|success       = 9
|first         = 12 August 1986
|last          = 11 February 1992
|stagedata     = 
{{Infobox Rocket/Stage
|type          = booster
|solid         = yes
|name          = [[Castor (rocket)|Castor 2]]
|number        = 6 or 9
|engines       = 1 × [[TX-354-3]]
|thrust        = {{cvt|258.9|kN}}
|SI            = {{cvt|262|isp}}
|burntime      = 37 seconds
|fuel          = [[Hydroxyl-terminated polybutadiene|HTPB]]/Al
}}
{{Infobox Rocket/Stage
|type          = stage
|stageno       = First
|name          = [[Thor (rocket)|Thor-ELT]]
|engines       = 1 × [[MB-3-3]]
|thrust        = {{cvt|866.7|kN}}
|SI            = {{cvt|290|isp}}
|burntime      = 270 seconds
|fuel          = [[RP-1]]/[[LOX]]
}}
{{Infobox Rocket/Stage
|type         = stage
|stageno      = Second
|engines      = 1 × [[LE-5]]
|thrust       = {{cvt|102.9|kN}}
|SI           = {{cvt|450|isp}}
|burntime     = 370 seconds
|fuel         = [[LH2]]/[[LOX]]
}}
{{Infobox Rocket/Stage
|type         = stage
|stageno      = Third
|diff         = optional
|engines      = 1 × [[UM-129A]]
|thrust       = {{cvt|77.4|kN}}
|SI           = {{cvt|291|isp}}
|burntime     = 68 seconds
|fuel         = [[solid rocket|Solid]]
}}
|derived_from=[[N-II (rocket)|N-II]]|derivatives=[[H-II]]}}
The '''H–I''' ('''H–1''') was a Japanese [[medium-lift launch vehicle]], consisting of a licence-produced American first stage and set of [[booster rocket]]s, and all-Japanese upper stages. The H in the name represented the use of liquid hydrogen fuel in the second stage. It was launched nine times between 1986 and 1992. It replaced the [[N-II (rocket)|N-II]], and was subsequently replaced by the [[H-II]], which used the same upper stages with a Japanese first stage.

The first stage of the H–I was a licence-built version of the [[Thor (rocket)|Thor-ELT]], which was originally constructed for the US [[Delta 1000]] rocket. The stage had already been produced under licence in Japan for the [[N-I (rocket)|N-I]] and N-II rockets. The second stage was entirely Japanese, using an [[LE-5]] engine, the first rocket engine in Japan to use a [[cryogenic fuel]]. On launches to [[Geosynchronous transfer orbit]]s, a [[Nissan]]–built [[UM-69A]] solid motor was used as a third stage. Depending on the mass of the payload, either six or nine US [[Castor (rocket)|Castor 2]] SRMs were used as [[booster rocket]]s.

[[File:Delta launches OSO 8.jpg|200px|thumb|The American Thor-ELT was used for the H-I.]]

==Launch history==
{| class="wikitable plainrowheaders"
|-
! scope="col" | Flight No.
! scope="col" | Date / time ([[Coordinated Universal Time|UTC]])
! scope="col" | Rocket, <br /> Configuration
! scope="col" | Launch site
! scope="col" | Payload
! scope="col" | Payload mass
! scope="col" | Orbit
! scope="col" | Customer
! scope="col" | Launch <br /> outcome
|-
! scope="row" rowspan = 2 style="text-align:center;|15(F)
| 12 August 1986,<br>20:45
| H-I
| [[Osaki Launch Complex]]
| [[Experimental Geodetic Payload|EGP]] ([[Experimental Geodetic Payload|Ajisai]])
| 
| [[Low Earth orbit|LEO]]
| 
| {{Success}}
|-
| colspan="8" |9 SRMs, 2 stages
|-
! scope="row" rowspan = 2 style="text-align:center;|17(F)
| 27 August 1987,<br>09:20
| H-I
| [[Osaki Launch Complex]]
| [[ETS-5]] ([[Kiku-5]])
| 
| [[Geosynchronous transfer orbit|GTO]]
| 
| {{Success}}
|-
| colspan="8" |9 SRMs, 3 stages
|-
! scope="row" rowspan = 2 style="text-align:center;|18(F)
| 19 February 1988,<br>10:05
| H-I
| [[Osaki Launch Complex]]
| [[CS-3A]] ([[Sakura-3A]])
| 
| [[Geosynchronous transfer orbit|GTO]]
|
| {{Success}}
|-
| colspan="8" |9 SRMs, 3 stages
|-
! scope="row" rowspan = 2 style="text-align:center;|19(F)
| 16 September 1988,<br>09:59
| H-I
| [[Osaki Launch Complex]]
| [[CS-3B]] ([[Sakura-3B]])
| 
| [[Geosynchronous transfer orbit|GTO]]
| 
| {{Success}}
|-
| colspan="8" |9 SRMs, 3 stages
|-
! scope="row" rowspan = 2 style="text-align:center;|20(F)
| 5 September 1989,<br>19:11
| H-I
| [[Osaki Launch Complex]]
| [[GMS-4]] ([[Himawari-4]])
| 
| [[Geosynchronous transfer orbit|GTO]]
| 
| {{Success}}
|-
| colspan="8" |6 SRMs, 3 stages
|-
! scope="row" rowspan = 2 style="text-align:center;|21(F)
| 7 February 1990,<br>01:33
| H-I
| [[Osaki Launch Complex]]
| [[MOS-1B]] ([[Momo-1B]])
| 
| [[Low Earth orbit|LEO]]
| 
| {{Success}}
|-
| colspan="8" |9 SRMs, 2 stages
|-
! scope="row" rowspan = 2 style="text-align:center;|22(F)
| 28 August 1990,<br>09:05
| H-I
| [[Osaki Launch Complex]]
| [[BS-3A]] ([[Yuri-3A]])
| 
| [[Geosynchronous transfer orbit|GTO]]
| 
| {{Success}}
|-
| colspan="8" |9 SRMs, 3 stages
|-
! scope="row" rowspan = 2 style="text-align:center;|23(F)
| 25 August 1991,<br>08:40
| H-I
| [[Osaki Launch Complex]]
| [[BS-3B]] ([[Yuri-3B]])
| 
| [[Geosynchronous transfer orbit|GTO]]
| 
| {{Success}}
|-
| colspan="8" |9 SRMs, 3 stages
|-
! scope="row" rowspan = 2 style="text-align:center;|24(F)
| 11 February 1992,<br>01:50
| H-I
| [[Osaki Launch Complex]]
| [[JERS-1|Japanese Earth Resource Satellite]] ([[FUYO-1]])
| 
| [[Low Earth orbit|LEO]]
|
| {{Success}}
|-
| colspan="8" |9 SRMs, 2 stages
|-
|}

When the H–1 was announced in 1986, company representative Tsuguo Tatakawe clarified that it would only be used to launch indigenous (i.e. Japanese) payloads, that only two launches per year could be mounted, and that the launch window consisted of a four-month period in which Japanese fishing fleets were not active (the falling launch boosters may damage fishing nets in the ocean waters).<ref>''Japan's H–1 and H–2 rockets'', [[Air & Space/Smithsonian]], February/March 1987, p. 19</ref>
==See also==
*[[Delta rocket]]
*[[H-II]]
*[[H-IIA]]
*[[PGM-17 Thor]]
* [[Comparison of orbital launchers families]]
* [[Comparison of orbital launch systems]]

==References==
{{reflist}}
*{{cite web|url=http://www.astronautix.com/lvs/delta.htm|title=Delta|first=Mark|last=Wade|publisher=[[Encyclopedia Astronautica]]|access-date=31 August 2008|url-status=dead|archive-url=https://web.archive.org/web/20130817180906/http://astronautix.com/lvs/delta.htm|archive-date=17 August 2013}}
*{{cite web|url=http://planet4589.org/space/lvdb/launch/Thor|title=Thor|first=Jonathan|last=McDowell|work=Orbital and Suborbital Launch Database|publisher=[[Jonathan's Space Report]]|access-date=31 August 2008|archive-date=1 August 2020|archive-url=https://web.archive.org/web/20200801135201/http://planet4589.org/space/lvdb/launch/Thor|url-status=dead}}
*{{cite web|url=http://space.skyrocket.de/doc_lau/h-1.htm|title=H-1|first=Gunter|last=Krebs|publisher=Gunter's Space Page|access-date=31 August 2008}}

{{Expendable launch systems}}
{{Japanese launch systems}}
{{Mitsubishi Heavy Industries}}
{{Thor and Delta rockets}}

[[Category:Mitsubishi Heavy Industries space launch vehicles]]
[[Category:Vehicles introduced in 1986]]
[[Category:Thor (rocket family)]]
[[Category:Japan–United States relations]]


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