Space-X DRAGON (manned/unmanned) capsule.

Despite polling “go”, there is one open item that must be closed out before Crew-3 can launch. During the Inspiration4 mission, a urine tube came unglued from the waste tank, which allowed urine to get into the fan system. While this had no impact on the Inspiration4 crew, teams have addressed the problem.

SpaceX welded the tube to the waste tank so it can no longer disconnect. SpaceX has completed all structural analysis and testing of the new design and has sent the data to NASA, which still has to complete its review; once they deem the fix as safe, they will close out the issue.

The fact that teams polled “go” even with this open item is a show of confidence in the reviews so far and an indication that this issue will be fully wrapped up at the L-2 day Launch Readiness Review.

After noticing this problem on Inspiration4, SpaceX and NASA teams decided to check the Crew-2 Dragon, Endeavour. They found that that urine tube had also disconnected on Endeavour and had leaked under the floor. However, this problem had not been noticed earlier as Crew-2 only relies on the Waste Management System (WMS) on-board Dragon during free-flight, using the station’s WMS during all other portions of the mission. However, as Inspiration4 used Dragon’s WMS for all three days of its flight, the problem was more apparent.
Consistent with the culture of “learn from flying,” several other changes have been made to Crew Dragon Endurance for this mission; in the highly unlikely event of all three of Dragon’s flight computers failing during reentry, Dragon now has a fourth fully redundant computer that can control the vehicle. This ensures that landing success and accuracy remain the same under extreme failure scenarios, further increasing Crew Dragon’s safety.

SpaceX has also made minor changes to the stitching on Dragon’s drogue parachutes. During post-flight inspections of Crew Dragon Resilience after Crew-1, teams noticed localized ribbon damage due to a debris strike on one of the drogue parachutes. The new stitching should further reinforce the parachute lines.

Additionally, Crew Dragon Endurance will refly Dragon’s nose cone for the first time, debut additional cleaning processes to reduce potential FOD (Foreign Object Debris), return to an earlier propulsion system seal which performed better than a newer design, debut a software change to mitigate radiation interference on communications, and showcase enhanced docking procedures to reduce interference while docking to the ISS.

 

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