CRS-17 Dragon arrives at ISS with cargo, stray cable

Derek Richardson

SpaceX’s CRS-17 Dragon spacecraft arrived at the International Space Station with fresh supplies and an unexpected cable that was supposed to fall away during launch.



The CRS-17 Dragon spacecraft contains about 5,500 pounds (2,500 kilograms) of crew supplies, equipment and experiments for the six-person Expedition 59 crew. After launching to the ISS on May 4, 2019, the vehicle rendezvoused with the outpost in the early-morning hours of May 6 with capture by the robotic Canadarm2 occurring at about 7:01 a.m. EDT (11:01 GMT).

Despite the nominal capture, there was one off-nominal issue during approach, an unexpected appearance of a cable extruding several feet from the capsule.

“We noticed a line on Dragon that we weren’t expecting to be there,” spacecraft communicator Brandon Lloyd said from Mission Control Center Houston over the space-to-ground radio loop. “Our initial looks at it is that we don’t expect any interference with the operations today.”

Expedition 59 Flight Engineer and NASA astronaut Nick Hague confirmed the ISS crew was seeing the cable too.

“It looks like a cable that’s maybe 6 to 10 feet in length running down from maybe the bottom of the capsule down into the service module,” Hague said.

To be on the safe side, ground teams had the Expedition 59 crew enter a few extra lines to the abort procedures, just in case the cable interfered with robotic arm capture operations.

It appears the mystery line may have been a connector from the Transporter Erector that improperly separated from the Dragon capsule during liftoff.

While on the launch pad, several cables are attached to the spacecraft and Falcon 9 rocket via the Transporter Erector, a truss-like structure that lifts the stack to the vertical position and holds various power and fuel lines that service the stack before liftoff. These attachments are designed to fall away as the rocket begins its climb toward space.

The cable did not interfere with the capture operations, but it is likely NASA and SpaceX will review why the line did not pull away as designed.

Once CRS-17 Dragon was around 33 feet (10 meters) below the Destiny laboratory module, Expedition 59 Flight Engineer and Canadian Space Agency astronaut David Saint-Jacques manually commanded the robotic Canadarm2 to place the arm’s latching end effector over the grapple fixture on the capsule.

Over the next several hours, a ground-based robotics team in Houston controlled the arm to move Dragon to its berthing point—the Earth-facing port of the Harmony module.

At 9:32 a.m. EDT (13:32 GMT), the spacecraft was in its final berthing position and several bolts were commanded to turn, firmly attaching the CRS-17 Dragon spacecraft to the ISS.

The hatches between Dragon and space station are expected to be opened later today. From there, the long process of unloading the cargo begins.

Additionally, sometime during its stay aboard the ISS, two pieces of hardware in the spacecraft’s trunk—the Orbiting Carbon Observatory-3 and Space Test Program-Houston 6 experiments—will be removed to be attached to external platforms on the space station.

CRS-17 Dragon is expected to remain attached to the ISS for about four weeks before returning to Earth. At the end of its mission, it will be loaded with trash and unneeded equipment before being unberthed. It will then drift away from the space station several hours before performing a de-orbit burn, splashing down in the Pacific Ocean less than an hour later.

Of note, this particular Dragon spacecraft is on its second mission to the ISS. It first flew during the CRS-12 mission in August 2017. With CRS-17 at the space station, six spacecraft are now docked or berthed to the outpost. The other five are the crewed Soyuz MS-11 and Soyuz MS-12 spacecraft, the Progress MS-10 and MS-11 freighters, and the recently-arrived NG-11 Cygnus spacecraft.

Video courtesy of SciNews