On 1 March 2016 Sierra Nevada Corporation announced about acquiring contract for providing Passive Common Berthing Mechanisms (PCBM) for Cygnus spacecrafts made by Orbital ATK.
Both Companies were recently granted with NASA Commercial Resupply Services 2 contracts what means that they remain potential competitors in resupply mission for International Space Station. Now, after SNC announcement it seems that both companies will cooperate in same business venture. This is next contract which was granted to SNC by Orbital ATK for Cygnus PCBM. First was referring to delivery eight PCBM for Cygnus spacecrafts utilized for first CRS missions. Worth of the contract was not unveiled by SNC or Orbital ATK. John Roth, vice president of business development for SNC’s Space Systems claims that every cooperation and any challenge related to the important space mission are worth taking:
“We are pleased to provide the berthing mechanism for Cygnus and aid in the continuous resupply and support of the ISS... SNC has always been focused on creating a diverse portfolio of reliable products that our industry partners can count on. We’ve been supporting critical missions throughout the solar system for more than 25 years, and we’re proud to be continuously adding to that legacy.”
Passive Common Berthing Mechanisms (PCBM) is part of Common Berthing Mechanism - berthing mechanism which is used on International Space Station for connecting every pressurized modules (only Russian modules are not equipped in CBM) and spacecrafts (again, Russian spacecrafts due lack of CBM are docking to Russian modules). It was designed by Boeing for NASA but now it is manufactured by different contractors. Passive CBM is kind of ring which is caught due the alignment guides by Active CBM. Next bolts and latches on ACBM are locking PCBM on ACBM in secure, sealed and pressurized position. After opening hatch in ACBM there is passage with diameter at 127 cm for transferring supplies by crew members from spacecraft to ISS. CBM also provides fuel, data and power transmission between ISS and spacecrafts (which is crucial for refueling ISS).
On picture above You can see Cygnus docked with CBM.