EDITOR’S NOTE: Updated Dec. 5 after launch delay.
A privately-funded airlock from Nanoracks will head for the International Space Station this weekend in the trunk of a SpaceX Cargo Dragon capsule, adding to the orbiting lab’s capacity for scientific experiments in another milestone for commercial space development.
The Bishop airlock module, owned by Houston-based Nanoracks, is secured inside the unpressurized cargo element of a SpaceX Dragon cargo ship awaiting launch from NASA’s Kennedy Space Center in Florida.
Weather permitting, the automated cargo mission is scheduled to take off from pad 39A on top of a Falcon 9 rocket at 11:17 a.m. EST (1617 GMT) Sunday. SpaceX called off a launch attempt Saturday due to poor weather in the Falcon 9 booster’s downrange recovery area.
In addition to roughly three tons of fresh food, supplies and experiments for the space station’s seven-person crew, the Dragon cargo craft will deliver the first commercial airlock module to the orbiting outpost.
“This is the going to be the first commercial module for the International Space Station, designed and built here at Nanoracks,” said Brock Howe, the company’s project manager for the Bishop airlock. “We’ve been working on the airlock for about five years.”
The expandable BEAM module from Bigelow Aerospace was also developed by a commercial company, but BEAM launched to the space station under NASA sponsorship.
The bell-shaped module is about the size of a small closet, measuring 6.9 feet (2.1 meters) in diameter and 5.8 feet (1.8 meters) long. Its dimensions were constrained by the size of the trunk on the Dragon cargo ship, the only spacecraft capable of ferrying large external payloads to the space station.
Including support hardware, the airlock weighs about 2,400 pounds (1,090 kilograms) at launch, according to NASA.
“If the volume (of Dragon’s trunk) was an inch bigger, our airlock would be, too,” said Mike Lewis, chief innovation officer at Nanoracks. “It’s big enough for people to climb in it.”
Nanoracks will use the airlock to move equipment into and out of the space station, expanding on a similar capability currently provided by an airlock inside the Japanese Kibo lab module.
Assuming the Cargo Dragon takes off Sunday, the SpaceX supply ship approach the space station for docking at 1:30 p.m. EST (1830 GMT) Monday, taking aim on a docking port on the zenith, or space-facing, side of the research lab’s Harmony module.
The Dragon set for launch this weekend is the first in a new design of cargo capsules based on SpaceX’s Crew Dragon astronaut ferry craft. The upgraded Dragon, or Dragon 2, can carry more equipment to the station, fly for longer periods of time, and will splash down in the Atlantic Ocean rather than the Pacific, expediting the return of time-sensitive biological specimens to scientists.
Within a few days after arriving at the space station, the lab’s Canadian-built robotic arm will reach into the Dragon’s trunk and pull out the Bishop airlock module. The Canadarm 2 will place the Bishop airlock on an unused berthing port on the end of the Tranquility module.
Astronauts will equalize pressure between the space station and the new module, perform leak checks, then enter the airlock to connect cables to link the new doorway with the station’s power and communications systems, according to Howe.
Nanoracks officials say they expect the airlock to be ready for operations within a week after the robot arm extracts Bishop from the Dragon trunk.
“The airlock is pretty simple in its utility,” Lewis said in a recent interview with Spaceflight Now. “It’s just an open cup that mounts on the space station. We use the hatch on the station, so a lot of the complex mechanisms and electronics are already there.”
Nanoracks and other users currently rely on the Japanese equipment airlock to transfer experiments and small satellites between the station’s internal cabin and the airless environment outside the complex.
“About five years ago, Nanoracks identified a need for customer and market demand for a bigger airlock, and one that could be opened a little more frequently than the Kibo one,” Howe said in a pre-launch conference call with reporters.
The airlock in Japan’s Kibo module works with a slide table, where astronauts can position equipment for transfer outside the space station.
“The Kibo airlock can transfer a piece of equipment about the size of a microwave oven, whereas this new Nanoracks airlock that we’ve been building will be able to handle something on the size of a about a refrigerator or freezer. So it’s about five times the size of the Kibo airlock.”
The internal compartment of the Bishop airlock is outfitted with tracks to help astronauts position experiments and small satellites inside the module. Then the astronauts will close hatches and the air will be pumped out of the airlock, allowing the station’s robotic arm to remove Bishop from its berthing location and position the module in space.
The airlock will expose experiments to the harsh thermal and vacuum conditions of low Earth orbit, allowing Nanoracks customers to try out Earth-imaging cameras, space science instruments, and new technologies. Astronauts could also mount small satellites inside the Bishop for deployment on the end of the robot arm.
Bishop is designed to accommodate satellites of up to 709 pounds, or 321 kilograms. The Nanoracks deployer currently at the station is sized for satellites of up to 220 pounds, or 100 kilograms.
The Nanoracks animation below shows how the company plans to use the Bishop airlock, with the space station’s robotic arm moving the module on and off its home on the Tranquility node. (EDITOR’S NOTE: The animation was created in 2018 and illustrates the Bishop module arriving on an older, now-retired version of SpaceX’s Dragon cargo vehicle.)
The airlock is designed for at least 10 pressure cycles per year over 10 years of operations, according to Nanoracks. The cadence of Bishop operations will depend on customer demand, the availability of the robot arm, and crew workload, officials said.
“We also have external payload mounts where we can host payloads on the airlock,” Howe said. “We can also host payloads inside the airlock while it’s still berthed to (the space station). So there are a lot of different environments that the scientists can use, a lot of different volumes and scientists can use, a lot of different payload power and data capabilities on-board the airlock that really will enhance their ability to do some really cool science on-board ISS.”
The Bishop airlock is also big enough to fit large space station hardware units that engineers might want to bring inside the complex for inspection and repairs. Using the airlock in that manner might reduce the number of spacewalks astronauts need to perform outside the station, officials said.
So far, Nanoracks has signed up NASA and the European Space Agency to use the Bishop airlock.
NASA pre-purchased six airlock cycles, with options for an additional four uses. ESA is paying Nanoracks for five airlock cycles.
“We’re thrilled to see both NASA and ESA leveraging commercially available opportunities on the space station,” said Jeffrey Manber, CEO of Nanoracks.
“This is how public-private partnerships are supposed to work,” Manber said in a statement. “Through our Space Act Agreement with NASA, we have been provided access to Node 3 (the Tranquility module) where the Bishop airlock will live. We then privately funded the Bishop airlock, using no taxpayer funds for the hardware, and are in turn providing a service at a competitive rate to both the U.S. and European governments, allowing the ISS to function at optimal levels of productivity.”
NASA plans to use the Bishop airlock to get rid of the space station’s trash as soon as next year. Astronauts will cram garbage and unneeded equipment inside the airlock, and then the airlock will release the trash containers into orbit to burn up during re-entry into Earth’s atmosphere within a few weeks to months.
“It’s not glamorous, but it’s necessary,” Lewis said.
A Japanese robotics company named GITAI also plans to test a small robot arm inside the Bishop airlock next year.
Lewis said Nanoracks invested somewhere between $15 million and $30 million in developing the Bishop airlock. Thales Alenia Space of Italy, which built several space station modules, fabricated the airlock’s pressure shell and delivered the hardware to Nanoracks in Houston for final outfitting before launch.
“The airlock also represents — from Nanoracks — the next step towards our goals, which are a commercial space station,” Howe said. ‘So this provides a lot of capabilities to enhance our engineering capabilities and our fabrication capabilities within our company to be able to get to those end goals of a commercial space station.”
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