April 23, 2021

SpaceX launches first in new line of upgraded space station cargo ships


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SpaceX’s Falcon 9 rocket climbs into the sky from pad 39A Sunday. Credit: Katie Darby / Spaceflight Now

An upgraded version of SpaceX’s Dragon cargo freighter launched Sunday from the Kennedy Space Center in Florida, loaded with 3.2 tons of supplies and experiments in the first of at least nine resupply flights to the International Space Station under a new NASA contract.

The cargo capsule lifted off on top of a 215-foot-tall (65-meter) Falcon 9 rocket at 11:17:08 a.m. EST (1617:08 GMT) Sunday, vaulting away from pad 39A with 1.7 million pounds of thrust from nine Merlin main engines.

The launch signaled the start of SpaceX’s 21st operational resupply flight to the space station, and the first using the company’s new generation of Dragon cargo capsules. The first 20 flights, spanning a period from 2012 until earlier this year, used a now-retired version of the Dragon spacecraft.

The second-generation Dragon supply ship is based on SpaceX’s Crew Dragon vehicle designed to fly with astronauts. On the cargo capsule, SpaceX removed the crew-rated ship’s launch abort system and replaced the vehicle’s touchscreen displays and seats with racks and freezers to hold supplies and experiments.

The Cargo Dragon rocketed to the northeast on top of the Falcon 9 rocket, flying with a first stage booster recovered after three previous flights.

Around two-and-a-half minutes into the mission, after the Falcon 9 surpassed the speed of sound and soared into the upper atmosphere, the booster shut down its engines and separated to begin descent maneuvers targeting a SpaceX landing platform parked several hundred miles northeast of the Kennedy Space Center in the Atlantic Ocean.

A Merlin engine tailored for firing in the airless vacuum of space ignited on the Falcon 9’s second stage and fired for six minutes to inject the Cargo Dragon into orbit.

The reusable 15-story first stage booster nailed its landing on SpaceX’s floating drone ship roughly eight-and-a-half minutes after liftoff, completing its fourth mission to space and back.

Moments later, the Cargo Dragon deployed from the rocket’s upper stage and opened its nose cone, revealing sensitive navigation sensors, a docking port, and forward thrusters for the planned 26-hour journey to the International Space Station.

The Cargo Dragon spacecraft is loaded with 6,553 pounds (2,972 kilograms) of equipment and research hardware, including a new commercial airlock developed and owned by Nanoracks for attachment to the space station.

There are also fresh food packages and provisions on-board for the space station’s seven-person crew.

According to SpaceX, the new Cargo Dragon spacecraft can haul about 20 percent more cargo volume than previous Dragon supply ships. The new cargo vehicle can stay at the space station for up to 75 days, more than twice as long as the first-generation Dragon spacecraft, said Sarah Walker, director of Dragon mission management at SpaceX.

The Cargo Dragon can be be reused up to five times, an improvement over the three-flight design of the first-generation Dragon cargo capsule. The new spacecraft will autonomously dock with the space station. Past Dragon cargo missions had to be captured by astronauts using the space station’s Canadian robot arm.

That change reduces the workload on the space station crew and makes the Cargo Dragon’s rendezvous profile nearly identical to the Crew Dragon, but the docking port used by the new Cargo Dragon has a narrower passageway than the connection used by the berthing system on the first-generation Dragon cargo capsule.

Northrop Grumman’s Cygnus supply ship is designed to berth to the space station with the robotic arm, offering transportation for bulkier items.

The upgraded cargo capsules will splash down under parachutes in the Atlantic Ocean east of Florida, rather than the previous recovery zone in the Pacific Ocean west of Baja California.

The Dragon recovery vessels stationed at Port Canaveral, Florida, have helipads, allowing SpaceX to remove cargo and scientific specimens from the Cargo Dragon for transport to the Kennedy Space Center within hours, instead of days, said Kirt Costello, NASA’s chief scientist for the International Space Station.

“That ability to get science back quickly is so important for space biology because we want to understand whether the effects that we’re trying to measure on orbit are due to the microgravity condition or due to the stress that a participant or a sample might see on landing,” Costello said. “So having those returned to the Cape really quickly and handed over to our scientists is a great new capability.”

The Cargo Dragons, like SpaceX’s Crew Dragons, will be refurbished between missions inside a facility at Cape Canaveral Air Force Station. Splashdowns in the Atlantic Ocean shorten the travel time for the spacecraft from the recovery zone to the refurbishment site.

SpaceX says all upgraded Cargo Dragon missions will launch from pad 39A at the Kennedy Space Center, the same facility that hosts crew launches. That allows ground teams to load last-minute supplies and time-sensitive experiments into the capsule using the access arm built for astronauts.

NASA signed a new cargo delivery contract with SpaceX for at least six upgraded Cargo Dragon space station flights in 2016. A NASA spokesperson said in November that the resupply contract has been extended to cover nine Cargo Dragon missions.

A view inside the Cargo Dragon spacecraft. Credit: SpaceX

After its successful launch Sunday, the Cargo Dragon was expected to fire its Draco thrusters in a series of maneuvers to fine-tune its course toward the space station.

The cargo freighter will approach the space station from below, then perform a half-circle flyaround to position itself above the station. The Cargo Dragon will perform the first-ever docking on the zenith, or space-facing, port on the station’s Harmony module at 1:30 p.m. EST (1830 GMT) Monday.

Once docked, the space station astronauts will open hatches leading to the Cargo Dragon to start unpacking the equipment.

The space station’s robotic arm will remove a commercial airlock, or doorway, from the Cargo Dragon’s trunk and place it on the Tranquility module.

The bell-shaped Bishop airlock, owned by Houston-based Nanoracks, will 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.

“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,” said Brock Howe, Nanoracks project manager for the Bishop airlock.

So far, Nanoracks has signed agreements with NASA, the European Space Agency, and the Japanese robotics company GITAI to use the new airlock to dispose of trash and perform experiments. Other customers could use the airlock to deploy small satellites.

The station’s robotic arm will periodically move the airlock on and off its home on the Tranquility module. The operations plan allows astronauts to mount satellites and experiments inside the airlock before the robot arm removes it to expose the payloads to the space environment.

The Bishop airlock is about five times bigger than the Kibo airlock. The new airlock also has exterior connections to host experiments outside the space station.

“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,” Howe said.

Read our earlier story for more information on the Bishop airlock.

The cargo version of SpaceX’s upgraded Dragon 2 spacecraft rolls out to pad 39A in preparation for its first launch. Credit: SpaceX

Other items on the way to the space station inside the Cargo Dragon include spares and consumables for the research lab’s new female-friendly toilet, live rodents and support hardware for biological experiments, and an upgraded catalytic reactor for the water processing system.

One experiment on the Cargo Dragon mission, named BioAsteroid, will look at how microbes might assist in mining material on asteroids.

“BioAsteroid is an experiment to study whether we can use microorganisms, bacteria or fungi, to extract economically interesting elements from asteroid material,” said Charles Cockell, professor of astrobiology at the University of Edinburgh and BioAsteroid’s principal investigator. “It’s essentially what we would call a biomining experiment, and we hope to learn whether we can use microbes to extract things like rare Earth elements and other elements that can be used to sustain a self-sustaining human presence throughout the solar system.”

The BioAsteroid experiment follows a similar investigation named BioRock, which demonstrated how microbes could extract valuable metals from basalt rock, a material that covers the moon and Mars. Now scientists want to study if a similar biomining setup could be used on asteroids.

Other payloads on the Cargo Dragon mission will help scientists learn more about how spaceflight affects cardiovascular cells and human brain organoids, yielding insights into how microgravity impacts the survival and metabolism of brain cells.

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Follow Stephen Clark on Twitter: @StephenClark1.


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