CRS-21 launches Bishop Airlock toward the ISS: How Many Firsts can SpaceX hit in one flight?

Bishop airlock overview configuration

By Dale Skran

With a multitude of records surrounding this flight, the most important aspect is certainly the main cargo—Nanorack’s Bishop airlock. This airlock was built by Boeing for Nanoracks, and will be the first commercial airlock on the ISS, offering substantially greater capacity for launching cubesats and providing more external real estate than the Japanese Kibo airlock. The BEAM module is arguably the first commercial component of the ISS; it was primarily experimental, and is currently used as a storage closet.

Although the successful December 6th launch of CRS-21 on a Falcon 9 to the ISS is the first flight under SpaceX’s second Commercial Resupply Services contract with NASA, the mission also hits many other new marks:

  • First time the crew access arm was used to load a cargo resupply mission.
  • The first time there will be two Dragon spacecraft docked to the International Space Station (uncrewed cargo Dragon and the Crew-1 Dragon).
  • First automated docking to the ISS for a SpaceX cargo resupply mission.
  • First flight of SpaceX’s upgraded cargo version of Dragon (Dragon 2).
  • The Dragon 2 spacecraft has double the capacity for powered lockers that preserve science and research samples during transport to or from Earth. The CRS-1 Dragon had six lockers available, whereas the Dragon 2 has 12.
  • The Dragon 2 also provides the capability for science payloads to remain in the spacecraft for the full duration of the mission. While the spacecraft is docked at the orbiting laboratory during CRS-21, four powered payloads will reside in Dragon 2, in effect making it a temporary extension of the ISS National Laboratory.
  • 24 total SpaceX flights in 2020, a new record for SpaceX (previous high was 21 in 2018), with at least two more planned for December.
  • The 68th Falcon 9 first stage landing.
  • The 35th F9 first stage landing on the drone ship Of Course I Still Love You.
  • The 100th successful flight of Falcon 9.
  • The 4th flight for this booster, which first launched DM2 in May with a crew.

CRS-21/Dragon 2 holds out the prospect of additional firsts as the mission proceeds, or on future missions:

  • CRS-21 will be the first cargo craft to splash down in the Atlantic Ocean upon the Dragon 2’s return to Earth.
  • Dragon 2 can stay attached to the ISS for 75 days, and be flown 5 times, although CRS-21 is only planned to stay at the station for 35 days.

We can look forward to the Bishop Airlock being the first of a large number of additional components planned for the ISS. The Russians plan to add the Multipurpose Laboratory Module Nauka in July 2021, and soon thereafter we should start to see the first Axiom sections being added to the ISS. The longest journey begins with a single step, and the Bishop Airlock is the first step toward a future of diverse, competing LEO commercial space stations.

Acknowledgements:  Some material in this blog post was taken from a NASA blog post written by Danielle Sempsrott, posted on December 4, 2020. Image of Bishop airlock overview configuration courtesy of Nanoracks.


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2 thoughts on “CRS-21 launches Bishop Airlock toward the ISS: How Many Firsts can SpaceX hit in one flight?”

  1. Thanks for the update on our Bishop Airlock. As always, good work from NSS. Small correction worth mentioning: The Airlock structure is two components, one provided by Boeing and the other by Thales Alenia Space in Italy. The lower shell went from Boeing’s plant in Huntsville to Turin, Italy where further hardware was developed. The final integration was performed by Nanoracks in our Houston shop and so too the Avionics before being shipped to the Cape where the final integration took place. Boeing is a valued partner of the Bishop Airlock program but one of several manufacturers. Thanks, as always.

  2. Jeffrey – big thanks for the clarification. I am looking forward to what Nanoracks will be doing in 2021, and congratulate you on joining Voyager Space Holdings.


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