International docking standard receives update
A major update to the International Space Station’s docking system standard has been approved by the International Space Station Multilateral Coordination Board (MCB), allowing for multiple types of spacecraft to dock with the orbiting lab.
The International Docking Standard System (IDSS) was first released in 2010 by the MCB. It established a common station-to-spacecraft equipment interface, enabling many types of spacecraft to dock together. It describes the physical features and design parameters of a standard interface without dictating a particular design.
“The latest additions to the docking standard further open the door for contributions by international agencies, as well as commercial enterprises for the International Space Station and exploration,” said William Gerstenmaier, MCB chair and NASA’s associate administrator for the Human Exploration and Operations Mission Directorate, in a press release.
The updated guidelines more than double the content that enables in-orbit crew rescue by a range of spacecraft types and allows international collaborative exploration with future spacecraft. It includes a full range of rendezvous operations with descriptions on passive rendezvous targets, which spacecraft use to locate and lock onto the space station for the approach.
“We have already seen benefits of this standard, creating the opportunity to develop additional standards for spacecraft design,” Gerstenmaier said. “The International Docking Adapters that will soon be installed on the space station are fully compatible with the docking standard, which means that any spacecraft can use the adapters in the future – from new commercial spacecraft to other international spacecraft yet to be designed.”
The first hardware to use the IDSS will be the International Docking Adaptors (IDA). These adaptors will be placed on the two Pressurized Mating Adapters (PMA) on the International Space Station that were used during the Space Shuttle program.
The PMA’s convert the Common Berthing Mechanism (CBM), to the Androgynous Peripheral Attach System (APAS), a family of docking ports that was originally developed for the Apollo-Soyuz Test Project in 1976.
APAS-95 is docking system that was used for the Shuttle-Mir program, and continued use with the ISS program. The IDA’s convert the APAS-95 to the NASA Docking System (NDS), which is compliant with the IDSS.
The NDS uses low-impact technology and will be the first docking system to allow for both docking and berthing.
The first of these new adapters, IDA-1, was part of the payload on SpaceX’s CRS-7 resupply mission. Unfortunately, during a launch mishap on June 28, 2015, the adapter was destroyed along with the rest of the Dragon cargo ship.
IDA-2 will launch sometime in 2016 and be placed in front of PMA-2. A new IDA, designated as IDA-3 will be built by Boeing, and be attached to PMA-3 sometime in the future.
These adapters will be visited by Boeing’s CST-100 Starliner and SpaceX’s Dragon 2 spacecraft sometime in 2017. Additionally, the European Space Agency (ESA) is developing its own docking port to be used on future spacecraft called the International Berthing and Docking Mechanism (IBDM). Because it is also compliant with the IDSS, it will be able to dock with the new docking adapters to be launched to the orbiting lab.
Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a blog about the International Space Station, called Orbital Velocity.