CRS-16 Dragon arrives at ISS after ground-based communications issue

The CRS-16 Dragon capsule approaches the International Space Station. Credit: ESA/Alexander Gerst

SpaceX’s CRS-16 Dragon capsule was captured by the International Space Station’s six-person Expedition 57 crew, despite a communications issue prompting a temporary retreat command being issued.

After spending three days catching up with the ISS following its Dec. 5, 2018, launch, the capsule made it to its hold point 10 meters below the Destiny laboratory at about 11:00 UTC Dec. 8. There, it waited for the crew to use the 17.6-meter Canadarm2 to reach out and capture the spacecraft. However, a ground-based communications issue was noticed by ground teams, and mission control in Houston commanded the crew to issue a retreat command, prompting Dragon to move to a 30-meter hold point.

According to NASA, the communications issue stemmed from a failed processor at a ground station in White Sands, New Mexico. The processor connects mission control to the Tracking and Data Relay Satellite System network

Once communications was back, the team tried again at 11:50 UTC. Dragon moved away from its 30-meter hold point and moved slowly to its capture point 10 meters below the outpost.

Capture officially occurred at 12:21 UTC by Expedition 57 Commander Alexander Gerst, who was at the controls of Canadarm2.

“We have confirmed capture. The arm is safed,” Gerst said following capture. “The International Space Station’s Expedition 57 crew would like to congratulate NASA, SpaceX and the international partners for a successful launch and capture of the 16th SpaceX Dragon cargo resupply mission, enabling the ISS program to continue performing its science program on this unique laboratory in Earth orbit. Also we congratulate the entire ISS team for managing six individual spaceships that will be simultaneously docked to the International Space Station from today on. This shows what a successful science and exploration program we have up here, making full use of the one and only microgravity laboratory that humanity has available for the benefit of all humans on planet Earth.”

Over the next couple hours, the arm was used remotely by ground teams to move the vehicle to the Earth-facing port of the Harmony module, where it will remain berthed for about a month. Installation occurred at about 15:36 UTC.

Dragon launched at 17:16 UTC from Cape Canaveral Air Force Station’s Space Launch Complex 40 in Florida. After its brief ride into orbit, it began its three-day chase with its more than 2,500 kilograms of science, supplies and other hardware.

This concludes a busy visiting vehicle period for the International Space Station program. In less than three weeks, four spacecraft arrived at the outpost: Russia’s Progress MS-10 cargo spacecraft on Nov. 18, Northrup Grumman’s NG-10 Cygnus resupply spacecraft on Nov. 19, Russia’s Soyuz MS-11 spacecraft with three new crew members on Dec. 3 and today’s CRS-16 Dragon.

In total, six spacecraft are attached to the outpost — a rare occurrence. The other two vehicles are Progress MS-09, which arrived in July 2018, and Soyuz MS-09, which arrived in June 2018.

Two more major activities remain for the ISS program before the end of 2018. On Dec. 11, a Russian spacewalk is set to be performed by the two Russian cosmonauts aboard the outpost: Oleg Kononenko and Sergey Prokopyev. Then on Dec. 20, Soyuz MS-09 is set to return to Earth with Gerst, Prokopyev and NASA astronaut Serena Aunon-Chancellor after their 6.5-month stay in orbit.

Once Soyuz MS-09 undocks, Expedition 57 will officially conclude and Expedition 58, which will include the already-aboard trio of Kononenko, NASA astronaut Anne McClain and Canadian Space Agency astronaut David Saint-Jacques. Kononenko will serve as commander of Expedition 58.