Update 1: 23:20 UTC the Spaceflight Meteorology Group (SMG) and the Cape Weather Officer predict 60% chance of NO GO for the launch tomorrow at 22:51 as well as a potential launch on Tuesday. (Today, the weather forecast started with 40% change of weather prohibiting the launches on Monday and Tuesday)
At 23:03 UTC NASA’s launch director Pete Nickolenko coordinating with the Mission Management Team (MMT) called off today’s launch of the Space Shuttle Endeavor on the STS-127 mission due inclement weather in the launch area as well as for a possible Return To Launch Site (RTLS) . There are launch windows opening at 22:46 UTC on Monday and 22:20 UTC on Tuesday. NASA will attempt another launch on Monday, July 13 at 22:51 UTC.
The RTLS abort is used if one or more engines shut down early and there is not enough energy to reach the Transatlantic Abort Landing (TAL) sites. The shuttle would pitch around toward KSC until reaching the gliding distance from the Shuttle Landing Facility (SLF) and carry out an abort landing. For launch to proceed, weather conditions within 20 Nautical Miles (roughly 37km) of the SLF must be forecast as acceptable for about 20 minutes after liftoff.
Today’s Launch Time-line:
~12:00 UTC – Chance of the weather prohibiting launch stays at 30% while the chance of weather prohibiting tanking is down to 10%. The primary concerns for launch are showers and thunderstorms within ~40km of the Shuttle Landing Facility (SLF).
13:16 UTC – Mission Management Team (MMT) has given a GO for tanking to start shortly after 13:30 UTC after engineering reviews have been completed and no problems with shuttle systems have been found in the post-lightning checks. 13:48 UTC – The countdown resumes at the T-6 hour mark after built-in hold.
13:48 UTC – STS-127 Launch Director Pete Nickolenko gave a GO to start the chill-down process of the liquid oxygen and liquid hydrogen fuel lines.
13:58 UTC – Taking of liquid hydrogen (at 20K) started in the slow-fill mode and the liquid oxygen (at 90.188 K) will follow at 14:28 UTC
14:28 UTC – Launch teams began liquid oxygen tanking in the slow-fill phase adding 1,200 liters every minute.
14:39 UTC – Liquid oxygen tanking changes to fast-fill mode at almost 6,000 l per minute. Liquid hydrogen is also in fast-fill phase adding almost 32,000 liters every minute into the external tank (ET)
15:47 UTC – The liquid hydrogen tanking has reached 98% and will transition from fast-full to top-off at 2700 l per minute.
16:05 UTC – Launch teams keep a close eye on the readings from the Ground Umbilical Carrier Plate (GUCP) but see no indications of a leak.
16:48 UTC – The shuttle tanking went into a stable replenish and the countdown entered a 2.5 hour long inbuilt hold at T-3 hours.
18:15 UTC – The Final Inspection Team conduct a detailed analysis of the vehicle as the team walks up and down the entire launch tower. Meanwhile, the Closeout Crew, a team of technicians that straps the astronauts into the shuttle, is already at Launch Pad 39A configuring the crew module for countdown and launch.
18:28 UTC – A Phase One Lightning Alert has been issued for the Kennedy Space Center but the situation is not unusual and the alert is likely to be canceled before the launch at 23:13 UTC.
18:30 UTC – STS-127 receive the weather briefing including weather at the abort landing sites, including the Return-To-Launch-Site (RTLS), Abort-To-Orbit (ATO) and Transatlantic-Abort-Landing (TAL)
18:53 UTC – The STS-127 crew suits-up and starts the preparations to board the Astrovan and head to the launch pad.
19:18 UTC – The countdown clocks have resumed at T-3 hours. Endeavour’s crew are preparing to depart crew quarters for the pad.
19:23 UTC – The STS-127 crew members depart the Kennedy Space Center’s Operations and Checkout Building and board the Astrovan which takes them the launch pad 39-A a few minutes away.
19:30 UTC – Currently the weather is NO-GO due to thunderstorm within 20NM (roughly 40km) of the launch site. The forecast still predicts a 30% chance of the weather violating the launch criteria due to storms.
21:50 UTC – The weather is again on NO-GO due to conditions for the Return To Launch Site (RTLS) abort. For launch to proceed, weather conditions must be forecast as acceptable for a possible RTLS landing at KSC about 20 minutes after liftoff.
21:58 UTC – Countdown enters a 10-minute planned hold at the T-20 minute mark
22:08 UTC – The countdown resumes at the T-20 minute mark
22:19 UTC – Countdown enters a 45-minute planned hold at the T-9 minute mark, during which the Mission Management Team and Launch Control team will conduct polls to give a final “go” decision for launch.
23:02 UTC – During the final GO / NO-GO polls Houston declares NO-GO for RTLS weather.
23:03 UTC – Phase 1Lightning warning just issued for KSC
23:03 UTC – The launch director in coordination with the MMT declared a launch scrub.