Boeing, SpaceX preparing sophisticated spacecraft ‘welcome mat’ at ISS
Boeing and SpaceX are currently in the process of building their own crewed spacecraft for missions to the International Space Station (ISS) under NASA’s Commercial Crew Program. When the CST-100 Starliner from Boeing and Crew Dragon for SpaceX start arriving in Earth orbit in 2017 and 2018, they are going to need a way to dock with the ISS so that crews can transfer to and from the ISS with safety and ease – enter the IDA.
The International Docking Adapter, or IDA for short, is a very sophisticated mechanism that will convert the current APAS-95 (Androgynous Peripheral Docking System 95) adapter originally used for docking NASA’s Space Shuttle to the ISS. This modification should accommodate these new crewed spacecraft.
The Boeing-built IDAs are designed to receive not only the Starliner and Crew Dragon vehicles but also NASA’s Orion crewed spacecraft, future cargo freighters, and other craft yet to be designed.
“It’s free for anyone to use,” said Mark Mulqueen, Boeing’s space station program manager, as reported in Spaceflight Now. “Sierra Nevada is using it, and SpaceX is designing their own similar system. They took our requirements and were able to make their own system. We’ll be using it for CST-100.”
The first International Docking Adapter, IDA-1, was supposed to reach the ISS last summer, but instead found itself at the bottom of the Atlantic Ocean still inside the SpaceX CRS-7 Dragon cargo vessel when the company’s Falcon 9 launch vehicle exploded 139 seconds after liftoff on June 28, 2015.
Mulqueen said that a second International Docking Adapter, or IDA-2, is complete and ready for launch this summer aboard SpaceX’s CRS-9 mission, tentatively scheduled to take to the Florida skies in mid-July. IDA-2 will be attached to the station’s forward Pressurized Mating Adapter 2 (PMA 2) on the Harmony module, also known as Node 2.
In March 2016, NASA awarded Boeing a $9 million contract to assemble a third International Docking Adapter called, appropriately, IDA-3. If everything continues to go as planned, it should be delivered to NASA as soon as March of next year (2017).
According to Spaceflight Now, Boeing was able to save money in the construction of IDA-3 by using 300 spare parts at facilities in both the U.S. and Russia, which comprised about 70 percent of the complete docking adapter.
NASA has tentatively planned to launch the third IDA on the SpaceX CRS-14 cargo mission in early 2018. When it arrives at the orbiting laboratory, IDA-3 will be attached to PMA-3 on the Harmony module.
As described in a May 24 Popular Science article, once at the space station, a robot attached to the outside of the ISS, named Dextre (also known as the Special Purpose Dexterous Manipulator or SPDM), will remove the IDAs from the trunk of the SpaceX Dragon’s cargo trunk and position them over their designated ports on the station.
Astronauts aboard the ISS will then perform an EVA to complete the installation process.
Each IDA weighs approximately 1,159 lbs (526 kilograms) and measure about 42 inches (1.1 meters) tall and 63 inches (1.6 meters) wide.
According to Space Station Live: “[…] are much more sophisticated than previous docking systems.” The docking adapter components include lasers and sensors which allow the ISS and arriving spacecraft to communicate digitally for sharing distance cues and enable automatic alignment and connection.
When both IDAs are eventually connected to the space station, Boeing and SpaceX will be able to have their manned craft attached to the complex at the same time.
IDA is part of the NASA Docking System (NDS). This is the space agency’s latest implementation of the International Docking System Standard (IDSS), an effort by the International Space Station Multilateral Coordination Board (MCB) to create a truly international spacecraft docking standard. NDS is also known as the international Low Impact Docking System (iLIDS).
Video courtesy of NASA Johnson
Larry Klaes is an author and freelance journalist specializing in news and educational work on the sciences. Klae's past endeavors include editor of SETIQuest magazine and President of the Boston chapter of the National Space Society (NSS). Klaes joined SpaceFlight Insider in 2016.