Whatever the next US human rated spacecraft is it is likely it will be able to use the International Berthing and Docking Mechanism (IBDM) that has been under development by NASA and the European Space Agency for more than two years now. The US Congress even directed NASA to develop such a mechanism with all space faring nations
Belgian company Verhaert Space is ESA’s prime for the European work on this IBDM and at the CEAS 2009 European air and space conference in Manchester, Geert Smet University of Leuven graduate student spoke of his work that contributed to the ESA studies
His presentation revealed that the IBDM’s origins is in the cancelled X-38 programme and that now the specification for the mechanism means it can dock or berth together vehicles as “small” as 5,000kg or as large as 80,000kg but the nominal spacecraft mass will be 21,500kg – enough for ESA’s Automated Transfer Vehicle or the Orion crew exploration vehicle
The planned Chinese space station is to be 60,000kg in mass. Or is it that 80,000kg would nicely suit the modules for a nuclear powered Mars ship?
Smet’s paper also refers to ongoing NASA work on its own Advanced Berthing Docking Mechanism project. This project was set to build a ground demonstration unit in 2005 but it seems to have been overtaken by the US agency’s work on LIDS and ATLAS for Orion crew exploration vehicle and Altair lunar lander
Smet’s paper also says: “The IBDM is a soft docking mechanism. Soft docking or low impact docking reduces the impact forces between the two docking vehicles. Current docking systems, like the probe and cone docking systems used for the Soyuz and Progress vehicles, rely on the impact speed of the spacecraft to activate the capture latches. The low-impact capture approach simplifies spacecraft docking operations by eliminating high-impact loads…”
But also recently there has been work on hard docking systems and this set of slides was presented at the Interoperability of Future Docking Systems conference held in the Netherlands in March, April of this year