2/x. Nothing preventing launch on the 16th at this time.
3/x. Forecast changes after rollout on Sunday, and based on timings for work to rollback, risk of rolling back in too strong winds was too great. So stayed at pad with predicitons then of max winds within limits.
4/x. Some issues being worked: Lose RTV on Orion probably going to snip off, can be reached form Crew Arm, and not replace; tear in engine rain covers that will be repaired; some water in Crew Arm that was taken care of. Those are behind us, I think.
5/x. One umbilical to Orion is out of its tray, but folks are going to move it back into place working on the swing arm to do that.
6/x. Ground side electrical umbilical on Hydrogen tail service mast that was exhibiting odd signals. Teams taking that apart now and working on replacing that harness if needed. Backup harness is here at KSC.
7/x. NASA reiterates that no wind readings on the sensors on the ML and lightning towers they have showed a breach of the certification limits on SLS.
8/x. NASA noted load readings on the rocket during the hurricane also did NOT exceed any certification limits during Nicole.
9/x. NASA notes they would have preferred to roll back to the VAB, but there wasn't time once the forecast changed after rolling out.
10/x. Near term plan: Power-up vehicle today. Program tests on Sunday, L-2 meeting Monday at 1600 local, then press to launch count.
11/x. Purges were on the whole time, and indications are that those purges worked and interfaces should be good.
12/x. NASA says there were higher winds readings, but at heights that aren't a concern as other elements on rocket indicate limits weren't exceeded.
13/x. @EmreKelly with a great question on how these hurricanes and climate change are potentially altering NASA's decision-making process on rolling out in hurricane season with percentage chances of storm development in the area. Answer: Yeah, we need to look at this.
14/x. No plans at this point to retorque bolts on LH2 fueling lines side. Major path items to the 16th are as Jim mentioned up-thread. "Normal cadence stuff is largely the critical path."
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THREAD: 1/ We got lots of good questions today on why #FalconHeavy was needed for #USSF44 instead of Falcon 9. You can actually see the reason (yay maths!!!) by comparing the Hotbird 13F & USSF-44 stage separation velocities.
2/ This is the center booster's shutdown velocity (2nd stage starting velocity) for USSF-44: ~14,270 km/h. That's 51% of low Earth orbit velocity. Now, compare that to the geostationary transfer orbit (GTO) mission of #Hotbird13F just a few weeks prior...
3/ On that GTO mission, the #Falcon9 booster (while still recovered) got the 2nd stage to a starting velocity of ~8,210 km/h. That 2nd stage had quite a lot more work to do (more deltaV needed) to haul the payload into the parking orbit before burning for GTO than USSF-44's did.
SLS rollback and future timelines news conference updates. Thread ⬇️
2/x: "We are absolutely going back out and we are absolutely going to do a wet dress rehearsal," NASA says. The exact timing and which option to do that are under discussion.
3/x: Charlie (Launch Director): the rollback is not a result of the leak; could have been worked at pad. But the ability to roll back helps but wasn't required.
#SLS Wet Dress Rehersal update from #NASA. A thread: 1/x
2/x: NASA confirms "minimal propellant operations" on the ICPS (interim cryogenic propulsion stage) with a heavily modified Wet Dress on Thursday, April 14 focusing on the Core Stage with T0 slated for 14:40 EDT / 18:40 UTC.
3/x: "We think this is a great path forward" said NASA official.
#NASA SLS Wet Dress Rehearsal teleconference updates for #Artemis. A thread...⬇️
1/x: There 2 primary test objectives and 5 secondaries. 1 primary and 3 secondaries have been completed. Cyrogenics are the outstanding categories.
2/x: On 4 Apr attempt, got the go for tanking. liquid nitrogen supply to center issue created issue that held them up. At 10am, got back in config to fuel. Started Liq oxy chilldown at 10:30a. Liq Ox flow started at 11a.
#Artemis post-Wet Dress Rehearsal scrub telecon updates from #NASA. A thread....⬇️
Teams knew Friday that the weather would be a challenge, but all was good to proceed. Severe weather materialized as expected Saturday afternoon. Lightning strike (4 strikes) inside pad on Saturday. 1/x
One lightning strike was "fairly rare" per meteorologists. It hit the catenary wires between two towers. Teams had prepared for lightning strikes and what would be needed to clear the vehicle if one happened. That plan was implemented. 2/x
NASA TV, Rob Navias, updating the situation now. Thread⬇️
- Zvezda's hatch was opened and crew was in process of getting things up and running when at 12:45pm EDT, Nauka began firing uncontrolled. ISS 45 degrees out of attitude. NO DANGER TO CREW! 1/x
Progress thrusters were used to regain ISS nominal attitude. Station is in a good configuration now. Russia teams will working Nauka thruster issue. 2/x
Zvezda's systems picked up the issue and tried to correct, but this attitude correction maneuver was quickly switched to Progress. 3/x