Editing Unity (ISS module)

{{italic title}}
{{Short description|American module of the International Space Station}}
{{Use American English|date=August 2020}}
{{Use dmy dates|date=August 2020}}
{{Infobox space station module
| spelling               = us
| module                 = ''Unity''
| module_image           = ISS Unity module (cropped).jpg
| module_image_caption   = ''Unity'' as pictured by {{OV|105}} shortly after it was berthed to [[Zarya (ISS module)|''Zarya'']] in December&nbsp;1998
| station                = [[International Space Station]]
| launch                 = 4 December 1998, 08:35:34{{nbsp}}[[Coordinated Universal Time|UTC]]
| launch_vehicle         = {{OV|105}}
| berthed                = 6 December 1998 ([[Zarya (ISS module)|''Zarya'']]&nbsp;forward)
| mass                   = {{cvt|11612|kg}}
| length                 = {{cvt|5.47|m}}
| width                  = 
| height                 = 
| diameter               = {{cvt|4.57|m}}
| volume                 = 
| stats_ref              = 
| configuration_image    = 
| configuration_size     = 
| configuration_caption  = 
}}

'''''Unity''''', also known as '''Node 1''', is the first [[United States|U.S.]]-built component of the [[International Space Station]] (ISS). This cylindrical module, constructed of steel by [[Boeing]] for [[NASA]], serves as the critical link between the orbiting laboratory's [[Russian Orbital Segment]] and [[US Orbital Segment]].

''Unity'' was launched on 4 December 1998, aboard the {{OV|105}} on [[STS-88]]. Two days later it was berthed to the previously launched [[Zarya (ISS module)|''Zarya'' module]], marking the first connection between ISS components. Its six [[Common Berthing Mechanism]] (CBM) locations ([[Glossary of nautical terms (A–L)|forward]], [[aft]], [[Port and starboard|port]], [[Port and starboard|starboard]], [[zenith]], and [[nadir]]) facilitate connections to other modules. At launch, two CBM locations were fitted with [[Pressurized Mating Adapter]]s (PMA), one of which enabled the mating with ''Zarya''.

Measuring {{convert|4.57|m}} in diameter and {{convert|5.47|m}} in length, ''Unity'' was built at NASA's [[Marshall Space Flight Center]]. It is the first of three connecting modules, joined by [[Harmony (ISS module)|''Harmony'']] and [[Tranquility (ISS module)|''Tranquility'']].

== Launch and initial berthing ==
''Unity'' (with its two attached PMAs) was carried into orbit as the primary cargo of the [[Space Shuttle Endeavour|Space Shuttle ''Endeavour'']] (OV 105) on [[STS-88]], the first [[Space Shuttle]] mission dedicated to assembly of the station. On 6 December 1998, the STS-88 crew mated the docking port of the PMA on the aft berthing port of ''Unity'' with the forward hatch of the already orbiting ''[[Zarya (ISS module)|Zarya]]'' module. (''Zarya'' was a mixed Russian-U.S. funded and Russian-built component launched a few days before aboard a [[Russia]]n [[Proton (rocket family)|Proton]] [[launch vehicle]] from [[Baikonur Cosmodrome|Baikonur]], [[Kazakhstan]].) 

== Connecting modules and visiting vehicles ==
''Unity'' has two axial and four radial [[Common Berthing Mechanism]] (CBM) ports. In addition to connecting to the ''Zarya'' module, ''Unity'' connects to the U.S. [[Destiny (ISS module)|''Destiny'' Laboratory Module]] (added on [[STS-98]]), the [[Integrated Truss Structure|Z1 truss]] (an early exterior framework for the station added on [[STS-92]]), the [[Pressurized Mating Adapter|PMA-3]] (also added on [[STS-92]]), and the [[Quest Joint Airlock|''Quest'' Joint Airlock]] (added on [[STS-104]]). During [[STS-120]] the ''[[Harmony (ISS module)|Harmony]]'' module was temporarily berthed to the port-side hatch of ''Unity''. ''[[Tranquility (ISS module)|Tranquility]]'', with its [[Cupola (ISS module)|multi-windowed cupola]], was attached to ''Unity'''s port side during the [[STS-130]] mission, and [[Leonardo (ISS module)|''Leonardo'']] was added to the [[nadir]] hatch during [[STS-133]].

In addition, the ''Leonardo'' and ''Raffaello'' [[Multi-Purpose Logistics Module]]s were each berthed to ''Unity'' on multiple missions. 

;Nadir
{| class="wikitable" style="text-align:center; font-size:100%"
! Spacecraft !! Docking ([[Coordinated Universal Time|UTC]]) !! Undocking (UTC)
|-
| [[STS-97]] || 2 December 2000, 19:59 || 9 December 2000, 19:13
|-
| [[STS-98]] || 9 February 2001, 16:51 || 16 February 2001, 14:05
|-
| [[Leonardo (ISS module)|''Leonardo'' PMM]] || 2011 || 2015
|-
| [[Cygnus CRS OA-4|CRS OA-4]] || 9 December 2015, 14:26 || 19 February 2016, 10:38 
|-
| [[Cygnus CRS OA-6|CRS OA-6]] || 26 March 2016, 10:51 || 14 June 2016, 11:43
|-
| [[Cygnus CRS OA-5|CRS OA-5]] || 17 October 2016, 23:45 || 27 November 2016, 23:36
|-
| [[Cygnus CRS OA-7|CRS OA-7]] || 22 April 2017, 12:39 || 4 June 2017, 11:05
|-
| [[Cygnus CRS OA-8E|CRS OA-8E]] || 14 November 2017, 12:15 || 5 December 2017, 17:52
|-
| [[Cygnus CRS OA-9E|CRS OA-9E]] || 24 May 2018, 12:13 || 15 July 2018, 10:20
|-
| [[Cygnus NG-10|CRS NG-10]] || 19 November 2018, 12:31 || 8 February 2019, 14:37
|-
| [[Cygnus NG-11|CRS NG-11]] || 19 April 2019, 11:31 || 6 August 2019, 13:30
|-
| [[Cygnus NG-12|CRS NG-12]] || 4 November 2019, 11:21 || 31 January 2020, 13:10
|-
| [[Cygnus NG-13|CRS NG-13]] || 18 February 2020, 11:16 || 11 May 2020, 13:00
|-
| [[Cygnus NG-14|CRS NG-14]] || 5 October 2020, 12:01 || 26 January 2020, 20:23
|-
| [[Cygnus NG-15|CRS NG-15]] || 20 February 2021, 17:36 || 29 June 2021, 16:32
|-
| [[Cygnus NG-16|CRS NG-16]] || 12 August 2021, 13:42 || 15 December 2021, 06:25
|-
| [[Cygnus NG-17|CRS NG-17]] || 21 February 2022, 12:02 || 28 June 2022, 07:00 
|-
| [[Cygnus NG-18|CRS NG-18]] || 9 November 2022, 13:05 || 21 April 2023, 08:37
|-
| [[Cygnus NG-19|CRS NG-19]] || 4 August 2023, 12:28 || 22 December 2023, 10:00
|-
| [[Cygnus NG-20|CRS NG-20]] || 1 February 2024, 12:14 || 12 July 2024, 08:00
|-
| [[Cygnus NG-21|CRS NG-21]] || 6 August 2024, 09:33 || 28 March 2025, 08:50
|}

;Forward
via [[Pressurized Mating Adapter|PMA-2]]
{| class="wikitable" style="text-align:center; font-size:100%"
! Spacecraft !! Docking !! Undocking
|-
| [[STS-96]]  ||align=center | 27 May 1999, 10:49|| align="center" | 6 June 1999, 02:02 
|-
| [[STS-101]]  ||align=center | 20 May 2000, 04:30|| align="center" | 26 May 2000, 23:03
|-
| [[STS-106]]  ||align=center | 8 September 2000, 12:45 || align="center" | 19 September 2000, 07:56
|-
| [[STS-92]]  ||align=center | 11 October 2000, 23:17 || align="center" | 24 October 2000, 20:59 
|}
* ''[[Destiny (ISS module)|Destiny]]'', 2001–present ([[Pressurized Mating Adapter|PMA-2]] was relocated to ''[[Destiny (ISS module)|Destiny]]'' forward during [[STS-98]] in 2001 and again to ''[[Harmony (ISS module)|Harmony]]'' forward during [[STS-120]] in 2007.<ref>{{cite web|title=NASA - PMA-2 Move Readies Station for Harmony Relocation|url=https://www.nasa.gov/mission_pages/station/expeditions/expedition16/exp16_pma2_move.html|access-date=2021-01-24|website=nasa.gov|archive-date=14 October 2021|archive-url=https://web.archive.org/web/20211014154543/https://www.nasa.gov/mission_pages/station/expeditions/expedition16/exp16_pma2_move.html|url-status=dead}} {{PD-notice}}</ref>)

;Aft
* ''[[Zarya (ISS module)|Zarya]]'' (via [[PMA-1]]), 1998–present

;Starboard
* ''[[Quest Joint Airlock|Quest]]'', 2001–present

;Port
* ''[[Tranquility (ISS module)|Tranquility]]'', 2010–present

;Zenith
* [[Integrated Truss Structure|Z1 truss]], 2000–present

== Details ==
[[File:Unity module interior.jpg|thumb|upright=1.0|right|Interior of Node 1 ({{asof|2005}})]]

Essential space station resources such as fluids, environmental control and life support systems, electrical and data systems are routed through ''Unity'' to supply work and living areas of the station. More than 50,000 mechanical items, 216 lines to carry fluids and gases, and 121 internal and external electrical cables using six miles of wire were installed in the ''Unity'' node.<ref name="NASA_unity">{{cite web|url=http://www.nasa.gov/mission_pages/station/structure/elements/node1.html#.Un1ZUZGViqQ|title=Unity Node|publisher=NASA|access-date=8 November 2013|archive-date=14 June 2014|archive-url=https://web.archive.org/web/20140614151305/http://www.nasa.gov/mission_pages/station/structure/elements/node1.html#.Un1ZUZGViqQ|url-status=dead}} {{PD-notice}}</ref> The primary structure of Unity is constructed of [[aluminium]].<ref name=NASA-Unity-CM-1999>{{cite web |url=http://spaceflight.nasa.gov/spacenews/factsheets/pdfs/unity.pdf|archive-url=https://web.archive.org/web/20000817055811/http://spaceflight.nasa.gov/spacenews/factsheets/pdfs/unity.pdf|url-status=dead|archive-date=2000-08-17|title=NASA Facts: ''Unity'' Connecting Module: cornerstone for a Home in Orbit|publisher=NASA|date=January 1999}} {{PD-notice}}</ref> 

During the space station construction, a crew member placed two speed limit signs on the hatch (leading into the FGB) in 2003, noting the orbital velocity in mph and km/h.<ref name="trivia">{{Cite web |title=Space Station Science Picture of the Day: Speed Limit |url=https://spaceref.com/status-report/space-station-science-picture-of-the-day-speed-limit/ |access-date=2022-05-06 |website=www.spaceref.com}}</ref>

Prior to its launch aboard ''Endeavour'', conical [[Pressurized Mating Adapter]]s (PMAs) were attached to the aft and forward berthing mechanisms of ''Unity''. ''Unity'' and the two mating adapters together weighed about {{cvt|11600|kg}}. The adapters allow the docking systems used by the Space Shuttle and by Russian modules to attach to the node's hatches and berthing mechanisms.<ref name="NASA_unity"/> PMA-1 now permanently attaches ''Unity'' to ''Zarya'', while PMA-2 provided a Shuttle docking port. Attached to the exterior of PMA-1 are computers, or multiplexer-demultiplexers (MDMs), which provided early command and control of ''Unity''. ''Unity'' also is outfitted with an early communications system that allows data, voice and low data rate video with [[Christopher C. Kraft Jr. Mission Control Center|Mission Control Houston]], to supplement Russian communications systems during the early station assembly activities. PMA-3 was attached to ''Unity''{{'}}s nadir berthing mechanism by the crew of [[STS-92]].

== Other nodes ==
[[File:Node 3 - Isolated view.jpg|thumb|upright=1.0|Node 3 (''Tranquility'') in space]]

The two remaining station connecting modules, or nodes, were manufactured in [[Italy]] by [[Alenia Aerospazio]], as part of an agreement between [[NASA]] and the [[European Space Agency]] (ESA). ''[[Harmony (ISS module)|Harmony]]'' (also known as Node 2) and ''[[Tranquility (ISS module)|Tranquility]]'' (also known as Node 3) are slightly longer than ''Unity'', measuring almost {{cvt|6.4|m}} long in total. In addition to their six berthing ports, each can hold eight [[International_Standard_Payload_Rack|International Standard Payload Racks]] (ISPRs). Unity, in comparison, holds just four ISPRs. ESA built Nodes 2 and 3 as partial payment for the launch aboard the Shuttle of the ''[[Columbus (ISS module)|Columbus]]'' laboratory module, and other ESA equipment.

== References ==
{{Portal|Spaceflight}}
{{Reflist|30em}}

== External links ==
* [https://web.archive.org/web/20000817055811/http://spaceflight.nasa.gov/spacenews/factsheets/pdfs/unity.pdf NASA Facts: ''Unity'' Connecting Module: cornerstone for a Home in Orbit] NASA, January 1999
* [https://www.youtube.com/watch?v=lg1AYWifAeo Expedition 15 - Tour of the ''Unity'' Node] filmed in July 2007 by [[Clayton Anderson]]

{{ISS modules}}
{{Orbital launches in 1998}}

[[Category:Components of the International Space Station]]
[[Category:Spacecraft launched in 1998]]