The NASA Docking System (NDS) is a

spacecraft docking and berthing mechanism Docking and berthing of spacecraft is the joining of two space vehicles. This connection can be temporary, or partially permanent such as for space station modules. ''Docking'' specifically refers to joining of two separate free-flying space ...

used on the

International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ( ...

(ISS), the Orion spacecraft, and the Starliner. The NDS is NASA's implementation of the International Docking System Standard (IDSS), an international spacecraft docking standard promulgated by the International Space Station Multilateral Coordination Board. The international Low Impact Docking System (iLIDS) is the precursor to the NDS. NDS Block 1 was designed and built by

The Boeing Company The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product ...

in Houston, TX, to meet the IDSS standards. Design qualification testing took place through January 2017. Using NDS, NASA developed the

International Docking Adapter The International Docking Adapter (IDA) is a spacecraft docking system adapter developed to convert APAS-95 to the NASA Docking System (NDS). An IDA is placed on each of the International Space Station's (ISS) two open Pressurized Mating Adapte ...

(IDA) to provide two IDSS-compliant docking ports on the ISS. The IDAs were delivered to the ISS starting in 2016. Each of two existing

Pressurized Mating Adapter The Pressurized Mating Adapter (PMA) is a class of spacecraft adapters that convert the Common Berthing Mechanism (CBM) used on the US Orbital Segment to APAS-95 docking ports. There are three PMAs located on the International Space Station (I ...

s has an IDA permanently attached, so the former PMA function is no longer available for visiting spacecraft. Since 2019, visiting spacecraft dock to the NDS ports on the IDAs. These include

Crew Dragon Dragon 2 is a class of partially reusable spacecraft developed and manufactured by American aerospace manufacturer SpaceX, primarily for flights to the International Space Station (ISS). SpaceX has also launched private missions such as Ins ...

, Cargo Dragon 2, and

Boeing Starliner The Boeing CST-100 Starliner
is a class of two partially

Design

The NDS docking mechanism is androgynous, the first system to use low impact technology and the first system to allow both docking and berthing. It supports both autonomous and piloted dockings and features pyrotechnics for contingency undocking. Once mated the NDS interface can transfer power, data, commands, air, communication and in future implementations will be able to transfer water, fuel, oxidizer and pressurant as well. The passage for crew and cargo transfer has a diameter of . In form and function NDS resembles the Shuttle/Soyuz APAS-95 mechanism already in use for the docking ports and

pressurized mating adapter The Pressurized Mating Adapter (PMA) is a class of spacecraft adapters that convert the Common Berthing Mechanism (CBM) used on the US Orbital Segment to APAS-95 docking ports. There are three PMAs located on the International Space Station (I ...

s on the

. There is no compatibility with the larger

common berthing mechanism The Common Mechanism (CBM) connects habitable elements in the US Orbital Segment (USOS) of the International Space Station (ISS). The CBM has two distinct sides that, once mated, form a cylindrical vestibule between modules. The vestibule is ...

used on the US segment of the ISS, the Japanese H-II Transfer Vehicle, the original

SpaceX Dragon American private space transportation company SpaceX has developed and produced several spacecraft named Dragon. The first family member, now referred to as Dragon 1, flew 23 cargo missions to the ISS between 2010 and 2020 before being retired. ...

, and Orbital Sciences' Cygnus spacecraft. NDS is compatible with the IDSS implementation on

SpaceX Dragon 2 Dragon 2 is a class of partially reusable spacecraft developed and manufactured by American aerospace manufacturer SpaceX, primarily for flights to the International Space Station (ISS). SpaceX has also launched private missions such as Ins ...

, both Crew Dragon and Cargo Dragon.

History

In 1996, Johnson Space Center (JSC) began development of the Advanced Docking Berthing System,Low Impact Docking System (2009-02)
/ref> which would later be called the X-38 Low-Impact Docking System. After the

X-38 The X-38 was an experimental re-entry vehicle designed by NASA to research a possible emergency crew return vehicle (CRV) for the International Space Station (ISS). The 1995–2002 program also developed concepts for a crew return vehicle design ...

was canceled in 2002, development of the mating system continued, but its future was unknown. In 2004, President George W. Bush announced his

Vision for Space Exploration Vision, Visions, or The Vision may refer to: Perception Optical perception * Visual perception, the sense of sight * Visual system, the physical mechanism of eyesight * Computer vision, a field dealing with how computers can be made to gain und ...

and NASA's 2005

Exploration Systems Architecture Study The Exploration Systems Architecture Study (ESAS) is the official title of a large-scale, system level study released by the National Aeronautics and Space Administration (NASA) in November 2005 of his goal of returning astronauts to the Moon and ...

was created in response, recommended the use of the Low Impact Docking System (LIDS) for the

Crew Exploration Vehicle The Crew Exploration Vehicle (CEV) was a component of the U.S. NASA Vision for Space Exploration plan. A competition was held to design a spacecraft that could carry humans to the destinations envisioned by the plan. The winning design was th ...

(which was later named Orion) and all applicable future exploration elements. The

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...

received the Soft-Capture Mechanism (SCM) on

STS-125 STS-125, or HST-SM4 (Hubble Space Telescope Servicing Mission 4), was the fifth and final Space Shuttle mission to the Hubble Space Telescope (HST) and the last solo flight of the Space Shuttle ''Atlantis''. The launch of the Space Shuttle ''Atl ...

. The SCM is meant for unpressurized docking, but uses the LIDS interface to reserve the possibility of an Orion docked mission. The docking ring is mounted on Hubble's aft bulkhead. It may be used for safely de-orbiting Hubble at the end of its service lifetime. In February 2010, the LIDS program became modified to be compliant with the IDSS and became known as the international Low Impact Docking System (iLIDS) or simply the NASA Docking System (NDS). In May 2011, the NDS critical design review was completed and qualification was expected to be completed by late 2013. In April 2012, NASA funded a study to determine if a less complex docking system could be used as the NASA Docking System that both met the international community's desire for a narrower soft capture system ring width, as well as providing the ISS a simpler active docking system compared to the then-planned design.

Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and p ...

's proposal was the Soft Impact Mating and Attenuation Concept (SIMAC), a design originally conceived in 2003 for the

Orbital Space Plane The Orbital Space Plane (OSP) program was a NASA spaceplane concept in the early 2000s designed to support the International Space Station requirements for crew rescue, crew transport and contingency cargo transport. It was part of the Space Lau ...

(OSP) Program. A leaked NASA internal memo from November 2012, stated that SIMAC had been chosen to replace the previous design and that the majority of the work on the NASA Docking System would be shifted from NASA JSC to Boeing. In August 2014, Boeing announced that the critical design review for the redesigned NDS had been completed. Following this change the IDSS was modified (to rev D), so the new design of the NASA Docking System is still compatible with the standard. IDA-1 was part of the payload on

SpaceX CRS-7 SpaceX CRS-7, also known as SpX-7, was a private American Commercial Resupply Service mission to the International Space Station, contracted to NASA, which launched and failed on June 28, 2015. It disintegrated 139 seconds into the flight aft ...

in June 2015, but was destroyed when the

Falcon 9 Falcon 9 is a partially reusable medium lift launch vehicle that can carry cargo and crew into Earth orbit, produced by American aerospace company SpaceX. The rocket has two stages. The first (booster) stage carries the second stage and pay ...

rocket exploded during ascent. IDA-2 was delivered successfully on SpaceX's

CRS-9 SpaceX CRS-9, also known as SpX-9, is a Commercial Resupply Service mission to the International Space Station which launched on 18 July 2016. The mission was contracted by NASA and is operated by SpaceX using a Dragon capsule. The cargo wa ...

mission in July 2016, and then installed on PMA-2 in August of that year during a spacewalk by Jeffrey Williams and

Kathleen Rubins Kathleen Hallisey Rubins (born October 14, 1978) is an American microbiologist and NASA astronaut. She became the 60th woman to fly in space when she launched on a Russian Soyuz spacecraft to the International Space Station (ISS) on July 7, 2016 ...

as part of Expedition 48.

Crew Dragon Demo-1 Crew Dragon Demo-1 (officially Crew Demo-1, SpaceX Demo-1, or Demonstration Mission-1) was the first orbital test of the Dragon 2 spacecraft. This first spaceflight was an uncrewed mission that launched on 2 March 2019 at 07:49:03 UTC, and a ...

was the first spacecraft to dock at this port on 2 March 2019. IDA-3 was launched on the SpaceX CRS-18 mission in July 2019. IDA-3 is constructed mostly from spare parts to speed construction. It was attached and connected to PMA-3 during a spacewalk on 21 August 2019.

References

* James L. Lewis
Advanced Docking Berthing System
NASA technical publication. Johnson Space Center. * James L. Lewis, Monty B. Carroll
Prototype Low Impact Docking System
NASA technical publication. Johnson Space Center.

External links

International Docking System Standard (IDSS) Interface Definitions Document (IDD)
Revision D April 2015 {{NASA space program Spacecraft components Spacecraft docking systems