SpaceX's cargo Dragon spacecraft returns to Earth
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A file photo of a previous cargo Dragon grappled by the International Space Station’s robotic arm. Credit: NASA
SpaceX’s CRS-19 Dragon is safely back on Earth today after 33-days in space, including 30 days berthed with the International Space Station.
The spacecraft splashed down just off the coast of Baja California on Jan. 7, 2020, carrying several tons of experiments and equipment returned from the ISS.
Launched on Dec. 5, 2019, the commercial cargo vehicle arrived at the ISS three days later with 2,617 kilograms of cargo and experiments for the Expedition 61 crew. This was the third time this particular capsule was flown. It previously sent cargo to the ISS as part of the CRS-4 and CRS-11 in 2014 and 2017, respectively.
Over the last month, the spacecraft was unloaded of its precious cargo and reloaded with experiments to be reviewed and studied on the ground as well as equipment that the six-person Expedition 61 crew no longer needs.
Using the Dextre manipulator attached to the Canadian robotic arm, an external science experiment called HISUI was extracted from Dragon’s trunk and installed on the outside of the space station. Credit: NASA
The process of returning Dragon started just after midnight UTC Jan. 7, 2020, when, following hatch closure, the spacecraft was unberthed and moved via the space station’s 17.6-meter-long robotic arm to its release position roughly 10 meters beneath the Destiny laboratory.
Shortly after 10:00 UTC, European Space Agency astronaut and Expedition 61 Commander Luca Parmitano commanded the arm to loosen its snares — the wires inside the latching end effector — and release Dragon. That officially occurred at 10:05 UTC with the spacecraft drifting away soon thereafter.
Over the course of the next several minutes, SpaceX’s CRS-19 Dragon spacecraft began a series of thruster firings to gradually push the vehicle away from the ISS and outside the 200-meter “keep-out sphere.”
It was during this phase, specifically during “departure burn 2,” that Parmitano noted that the plume from Dragon’s thrusters impacted the UltraFlex solar arrays on the NG-12 Cygnus, causing them to shake.
“We noticed that while the jets were firing for the departure burn 2, the blast from the engines was shaking quite vigorously the solar panels on Cygnus 12,” Parmitano said.
According to NASA public affairs officer Dan Huot during the live coverage of the departure, ISS management teams on the ground do a lot of analysis regarding thruster plumes around the outpost and will most certainly review this situation to see if there was any adverse impact to the spacecraft. It’s unclear if this will affect future Dragon departures.
Roughly seven minutes after departure burn 2, the third departure burn occurred. This was the largest of the three firings of Dragon’s thrusters, pushing the spacecraft well out of the approach ellipsoid, which is roughly 2 kilometers by 4 kilometers.
CRS-19 Dragon on approach to the space station. Credit: NASA
During the next several hours, SpaceX teams in Hawthorne, California, began preparing the spacecraft for reentry. This involved closing the “Guidance, Navigation and Control” bay door and turning the vehicle in a retrograde position to fire the Draco thrusters for nearly 13 minutes, slowing Dragon enough to intersect the upper atmosphere and fall back to Earth.
After the deorbit burn, which occurred around 14:10 UTC, the trunk of the spacecraft is jettisoned. It is not designed to survive reentry. The capsule, however, has a heat shield. Following its plunge into the atmosphere, it slows down enough for a series of parachutes to open, culminating in three main chutes.
Dragon splashed down in the Pacific Ocean at 15:42 UTC. SpaceX recovery ships are expected fish the capsule out of the water where it will be transported to Los Angeles. There, time-sensitive cargo will be offloaded and delivered where they need to go. The remaining cargo and supplies will be trucked to McGregor, Texas, before they are offloaded and transported to the Johnson Space Center in Houston.
This was the second-to-last Dragon version 1 spacecraft to fly. CRS-20, which is scheduled for later this spring, will be the last and also the final flight of the original Commercial Resupply Services contract from NASA.
Both Northrop Grumman with its Cygnus spacecraft and SpaceX with its Dragon version 2 cargo vehicle — a derivative of its Crew Dragon spacecraft — will continue under the CRS2 contract.
The first Dragon version 2 cargo ship is expected to fly later this year as part of the CRS-21 mission.
