Having completed the Flight Readiness Review for the United States Crew Vehicle 3 (USCV-3) mission, NASA, ESA, JAXA, and SpaceX teams have given the green light for Crew-3 to launch on October 31 at 02:21 EDT (06:21 UTC) and for Crew-2 to return to Earth no earlier than November 4.
Crew-3 will mark SpaceX’s fifth crewed mission and their third operational crew flight to the International Space Station (ISS). If this launch window is met, the crew will dock with the ISS on November 1 at 00:10 EDT (04:10 UTC).
Flight Readiness Review
Crew-3 is the eighth Crew Dragon mission, following the Pad Abort Test, DM-1, In-Flight Abort, DM-2, Crew-1, Crew-2, and Inspiration4 missions. Crew-3 will launch NASA astronauts Raja Chari, Thomas Marshburn, and Kayla Barron along with ESA astronaut Matthias Maurer. The crew will remain on the ISS for roughly six months — when the Crew-4 astronauts will replace them.
Originating with NASA during the Space Shuttle era, the FRR, or Flight Readiness Review, is the most important “go” for launch decision point before the countdown. It has now become an industry standard. For the commercial crew program, NASA mandates that an FRR involving all entities be conducted.
The review started early on Monday morning, October 25, with the Crew-3 astronauts. NASA started the tradition of opening all FRRs with the crew, helping to ensure that no corners will be cut during the process. As Crew-3 is already SpaceX’s fifth crewed mission, NASA and SpaceX have emphasized the culture of learning from flights, going as far as saying “don’t ever assume you know what’s going to happen with the vehicle.” These processes help ensure that teams do not get complacent and that the missions are as safe as possible.
The Crew-3 astronauts during emergency launch pad evacuation training at the Kennedy Space Center in mid-2021. Left to right: Raja Chari, Kayla Barron, Matthias Maurer, and Thomas Marshburn. (Credit: SpaceX)
After the review, teams unanimously polled “go” to launch to the ISS, where the Crew Dragon Endurance will dock to the forward port at IDA-2 on the Harmony module.
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.
Thanks to @astro_matthias and @Astro_Raja for helping me and Kayla Barron suit up for one last NBL run before launch. Launch now scheduled for October 30 at 2:43 AM EDT! pic.twitter.com/ltP4kSh9v6
— Thomas H. Marshburn (@AstroMarshburn) October 10, 2021
To ensure the leaked urine doesn’t endanger the Crew-2 astronauts during reentry, SpaceX conducted a large number of tests and analyses on the ground, including placing Oxone urine (Oxone is placed in urine aboard Dragon to reduce ammonia) next to the aluminum that is used on Dragon in a controlled environment to mimic the conditions aboard the ISS.
SpaceX and NASA found that the contamination posed no risk to the crew, in large part due to the corrosion-resistant aluminum used on Dragon.
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.
With the FRR milestone passed, SpaceX will now conduct a static fire of the Falcon 9 on Wednesday around 23:00 EDT (03:00 UTC on Thursday). The day after, the crew will conduct the dry dress rehearsal.
Crew-3 Launch
The Crew-3 mission will launch in a brand new capsule, C210 Endurance, and on a flight-proven Falcon 9 Block 5, B1067-2. B1067 has flown one previous time, on the CRS-22 mission which launched on June 3, 2021.
Falcon 9 and Dragon were integrated on October 25 inside the packed Horizontal Integration Facility (HIF) at LC-39A. In addition to the Falcon 9 and Dragon, the HIF contains three Falcon Heavy cores: B1064, B1065, and B1066, which will be used on the upcoming USSF-44 mission.
The rocket’s static fire, which will take the rocket through an entire countdown, fueling, and pressurization sequence up until the moment of liftoff, will not take place with the crew onboard.
Final crew practice will instead take place the day after the static fire when SpaceX will conduct the dry dress rehearsal. As the name implies, the dry dress rehearsal is a full run-through of launch-day operations, done without fueling the rocket, to ensure the astronauts and the launch team are ready for the events on launch day.
The Crew-3 mission is currently set to launch on October 31 at 02:21 EDT (06:21 UTC). The launch has an instantaneous window.
Crew-3 astronauts test out their flight hardware ahead of launch later this month pic.twitter.com/nRW2mM6MpM
— SpaceX (@SpaceX) October 13, 2021
The Falcon 9 first stage burn will last approximately two and a half minutes. The stages will then separate before the MVacD engine ignites. The second stage will then burn for roughly six minutes and 10 seconds before shutting down.
Meanwhile, B1067-2 will conduct two burns: a reentry burn and a landing burn. These burns will bring the Falcon 9 first stage to a soft touch down on one of SpaceX’s autonomous spaceport drone ships (ASDS) roughly 540 km offshore.
After second engine cut-off, Dragon will stay attached to the second stage for approximately three minutes to check its attitude and rotation rates and allow the vehicle’s remaining propellants to settle in the second stage tanks.
If everything is nominal, Dragon will then be deployed to perform several phasing burns to raise its orbital altitude to that of the ISS. Dragon will then dock to the station roughly 22 hours after launch, at 00:10 EDT (04:10 UTC) on Monday, November 1.
(Lead image: Crew Dragon Endurance arrives in the HIF at LC-39A for integration to the Falcon 9 rocket ahead of the Crew-3 mission. Credit: SpaceX)
https://news.google.com/__i/rss/rd/articles/CBMiM2h0dHBzOi8vd3d3Lm5hc2FzcGFjZWZsaWdodC5jb20vMjAyMS8xMC9jcmV3LTMtZnJyL9IBAA?oc=5
2021-10-26 14:30:08Z
52781962367215
Tidak ada komentar:
Posting Komentar