Crew Tests SpaceX EVA Suit’s Thermal Systems And Mobility

The Polaris Dawn completed its planned extravehicular activity (EVA) on Thursday morning September 12. The EVA lasted about 20 minutes with Commander Jared Isaacman and Mission Specialist Sarah Gillis exiting the craft to evaluate the SpaceX-designed EVA suit for mobility and thermal regulation.

The EVA was the first from a Dragon crew spacecraft and the first-ever for a commercial mission with civilian astronauts. Preparing Dragon for the EVA began shortly after launch on September 10 when the crew initiated the process to reduce Dragon’s internal nitrogen level as its oxygen level was raised. This took two days and the purpose was to reduce the risk of decompression sickness caused by nitrogen bubbles in the astronauts’ blood when the hatch opens to the vacuum of space for the EVA.

During the replacement of nitrogen the crew put on the EVA suits and performed mobility tests inside the vehicle. Several hours prior to the hatch opening, the crew prepared the cabin for vacuum and did final leak checks on the suits. The cabin was then vented and its pressure was slowly lowered to equalize with the vacuum of space. The hatch was opened and the entire crew was exposed to the vacuum.

The first crew member used the Skywalker mobility aid to egress the craft and performed the suit tests for about 12 minutes before the returning to the cabin. Once seated, the second crew member egressed and performed identical tests on the suit. When complete that crew member reentered the cabin and closed the hatch.

After the EVAs were completed, the cabin is slowly repressurized. When it was safe, the astronauts removed the suits, then ate and rested.

FMI:  www.spacex.com/