T-(time) used in the rightmost column is time remaining until launch holds included as L-(time) given in the grey-hued column is time remaining until launch holds not included. A poll points to a special procedure used during countdowns. Decisions about countdown and launch are based on a poll process where NASA launches officers takes the advice of other members of the launch team
The STS-131 Space Shuttle mission is a mission to the ISS, where the astronauts will hang a spare ammonia coolant tank and bring varied cargo inside the Multi-Purpose Logistics Module Leonardo. Liftoff is scheduled for 6:21 a.m. EDT on Monday, April 5th, 2010, from the launch pad 39A at the Kennedy Space Center, in Florida. During the mission's stay at the ISS, 4 women-astronauts will be in space at the same time -a first in the history of the space conquest- as will be too 2 Japanese astronautes. The STS-131 Space Shuttle mission is one of four last mission of the Space Shuttle program before the fleet is retired by fall 2010
| April 2nd,3 a.m. | na | the STS-131 countdown has begun by 3 a.m. on April 2nd, by T-43 hours that is. Two days of preparations to launch kept unfolding then until the launch pad rotating structure was rolled off, shortly before the External Tank tanking began, on April 4th by 9:28 p.m. A few weeks before launch, all the teams involved participated into a launch dress rehearsal called the 'Terminal Countdown Demonstration Test', a standard part of prelaunch training giving first-time fliers a chance to practice these procedures and providing a refresher course for veteran astronauts. It gives the entire team the opportunity to work together before launch day |
| 01:15 a.m. | L-05:06 | the countdown is now halted in a built-in hold which began at T-3 hours and is to end by 2:26 a.m. Shuttle Discovery, with the launch stack, are standing in the million-candlepower xenon lights trained on the vehicle from the pad perimeter. Weather forecasters predict an 80 percent chance of conditions favorable to launch. Shuttle Weather Officer Kathy Winters is expected to give a weather update in the next few minutes. The Launch Director and the team of launch controllers are monitoring the countdown from Firing Room 4 in the Launch Control Center. Meanwhile Discovery's seven astronauts are awake and will begin suiting up shortly |
| 01:22 a.m. | L-04:59 | Discovery's External Tank has been loaded with half a million gallons of chilled liquid oxygen and liquid hydrogen as the tanking operations had began at 9:28 p.m and concluded by 12:21 a.m. Fueling was delayed by about half an hour while the launch team investigated a voltage spike in a fuel cell pump motor. Small amounts of both propellants will continue to warm up from now, and evaporate throughout the countdown, with valves at the pad cycling on and off, replacing the lost propellant through 'stable replenish.' |
| 01:23 a.m. | L-04:58 | since tanking has been completed, the Final Inspection Team, often called the 'Ice Team,' is getting an up-close look at Discovery and the pad structures for any ice development. Any such occurrence would be characterized and reported to launch management before the team departs the launch pad. At the same time, the Closeout Crew is working inside the environmentally controlled White Room at the end of the orbiter access arm, and in the shuttle's crew module, preparing for the astronauts' arrival. Astronaut Chris Cassidy is serving today like the prime astronaut support person, setting up for crew boarding and checking the communications systems |
| 02:00 a.m. | L-04:21 | as far as the weather is concerned, a high pressure system has resulted in pleasant conditions overnight at the Kennedy Space Center. Skies are partly cloudy and there's a light wind from the East. Weather forecasters are somewhat concerned about the possibility of fog developing due to the stable conditions and temperatures close to the dewpoint. The wind may help keep fog development at bay however. Weather officials for today's countdown include Shuttle Weather Officer Kathy Winters of the 45th Weather Squadron, forecasters with the National Weather Service's Spaceflight Meteorology Group based in Houston, as a non-mission member astronaut John Casper is serving as the weather coordinator in Kennedy's Firing Room 4. Additionally, another non-mission member astronaut plays like the weather interface in the Mission Control Center |
| 02:02 a.m. | L-04:19 | as the STS-131 mission crewmembers now have taken a meal, allowed for a photo session and endured a medical check, they are to don their bright-orange launch-and-entry suits. Those suits, which are known as the 'Advanced Crew Escape Suit', or ACES, are providing a cocoon of air and storage for a multitude of survival tools in case of a emergency after launch. Suiting up can last nearly one hour. For departure, astronauts are helped to dress with suit technicians and others as, when returning Earth from the orbit, they will have to rely on their own experience and the help of their crewmates to don the heavy suits |
| 02:13 a.m. | L-04:08 | preparations are keeping now to a launch by 6:21 a.m. |
| 02:26 a.m. | L-03:55 | counting is moving again! The T-3 hours built-in hold has now ended and the countdown is resuming |
| 02:33 a.m. | L-03:48 | astronauts have now stepped out of the Operations and Checkout Building, waved to the gathered crowd of friends, space workers and news media and climbed into the Astrovan, NASA's vintage, modified Airstream mobile home. The Astrovan is now on its way to Launch Pad 39A under heavy security. In the van, astronauts have the option of plugging into cooling units if they begin to feel too warm in their suits |
| 02:40 a.m. | L-03:41 | the Astrovan is making two stops along the drive out to the launch pad. First to allow the non-mission member astronaut to step out and enter a car which will ride him to the runway of the Shuttle Landing Facility where he will pilot weather-observing flights later into the countdown. Minutes later, the Astrovan is pausing again at the driveway to the Launch Control Center, dropping off the Director of Flight Crew Operations and Chief Astronaut |
| 02:44 a.m. | L-03:37 | during the journey further to the launch pad, the only people riding in the silver Astrovan, aside the STS-131 crew, is a technician who will serve as part of the Closeout Crew in the White Room. Arriving by launch pad 39A, the van will pass through the pad perimeter's gate, driving up the concrete hardstand and eventually letting the astronauts off near the pad elevator |
| 02:53 a.m. | L-03:28 | the astronauts have paused for a few moments for a photo session at the base of the launch stack, they are now riding the pad's elevator up to the 195-foot level where the White Room crew are to help them into the orbiter |
| 03:03 a.m. | L-03:18 | the mission's Commander is the first to board. The commander's seat is Seat 1 on the front-left side of the Space Shuttle flight deck |
| 03:06 a.m. | L-03:15 | during the next 43 minutes, all astronauts of the mission are going to board, one or two astronauts at a time since the White Room gets crowded with Closeout Crew members and equipment. Closeout Crew is helping the astronauts put on their communications caps, parachute packs and other gear. The mission's pilot, today, boarded in third position to Seat 2 which lies on the front-right side of the flight deck, beside the commander's. Astronauts are seating either by the orbiter's flight deck, or middeck |
| 03:17 a.m. | L-03:04 | Launch Weather Officer Kathy Winters just informed the Launch Director that cloud cover above the Shuttle Landing Facility is too low and thick, violating launch constraints. Conditions in Central Florida can change very quickly, so although weather is 'red' for now, it may go 'green' again into the countdown |
| 03:32 a.m. | L-02:49 | once seated and strapped on board, astronauts will spend the rest of the countdown lying on their backs as the orbiter is standing vertically with the launch stack. As they get seated, the astronauts begin two-way checks of all their communications channels. During these tests, the crew members will talk with the Orbiter Test Conductor in the Launch Control Center and with the Flight Director in mission control |
| 03:49 a.m. | L-02:32 | weather parameters are back to a 'go' status as the cloud deck above the area has scattered. The weather parameters effect both the launch itself and the Shuttle Landing Facility, as the runway there serves like the first emergency landing location for the Space Shuttle |
| 03:55 a.m. | L-02:26 | we are at T-1 hour and 30 minutes and couting. The Closeout Crew is ready to finish up work in Discovery's crew module, with, before closing the hatch, the flight deck and middeck are inspected to make sure 'non-flight' items, such as standing platforms, switch guards and protective covers, are all removed from the orbiter |
| 04:22 a.m. | L-01:59 | the Closeout Crew is now closing the orbiter's side hatch. Before the hatch could be moved into position, the inner and outer seals were cleaned to ensure a solid overlap. The seals also will be pressurized, further strengthening the seal |
| 04:27 a.m. | L-01:54 | by T-1 hour, the Closeout Crew is checking the cabin and hatch seals for any leaks. Countdown is keeping to be on schedule to a launch by 6:21 a.m. |
| 04:35 a.m. | L-01:46 | astronaut Chris Ferguson is piloting the Shuttle Training Aircraft, a modified Gulfstream jet used to mimic the flying characteristics of a landing shuttle orbiter, and until after liftoff he will patrol the skies throughout the launch area, monitoring weather conditions and reporting his observations to launch management. Weather, now, is still 'go', with a slight concern however that development of fog or a cloud ceiling could interfere with an emergency shuttle landing, if one were needed. Forecasters continue to predict an 80 percent chance of good weather for launch |
| 04:57 a.m. | L-01:24 | by T-30 and counting, the Closeout Crew continues its work in the White Room outside Discovery's crew access hatch. The cabin will be vented and the vent valves closed, and the White Room will be configured for launch before the team departs. The ground launch sequencer main line computer program has been activated and is processing data. It will continue monitoring key commands and systems until it assumes control of the countdown at T-9 minutes |
| 05:06 a.m. | L-01:15 | the countdown clocks are now holding at the T-20 minutes built-in hold |
| 05:11 a.m. | L-01:10 | the Closeout Crew has finished securing the White Room for launch and is departing the launch pad, retreating to a roadblock a safe distance away. The team is available to return quickly to the pad if needed |
| 05:16 a.m. | L-01:05 | countdown resuming! T-20 minutes and counting. A final built-in hold will begin at the T-9 minute mark. Discovery's primary and backup avionics software systems are being switched into 'OPS 1,' or launch mode. Of the shuttle's five general purpose computers, four run the primary avionics software and the fifth runs the backup flight system |
| 05:22 a.m. | L-:59 | weather is 'go' for a launch by 6:21 a.m. and is expected to remain favorable through the remainder of the countdown. No technical issues are being discussed, and all is quiet in the Launch Control Center |
| 05:26 a.m. | L-:55 | the Closeout Crew has reached the roadblock. There are no nonessential personnel left inside the 'launch danger area,' and the Kennedy area has been declared clear for launch |
| 05:27 a.m. | L-:54 | T-9 minutes and now holding! We have entered the final, 45-minute built-in hold of the countdown today. The length of the T-9 minute hold is typically adjusted slightly to target a precise launch time so to be in agreement with the relatively short launch window to the International Space Station |
| 05:42 a.m. | L-:39 | astronaut Chris Ferguson continues to fly the Shuttle Training Aircraft in the Kennedy Space Center area to keep an eye on the weather. His real-time observations are an asset to weather forecasters, who rely on his reports in addition to ground-based observations and those gathered from satellite and radar imagery. Although some patchy fog has been spotted around the runway of the Shuttle Landing Facility, it has not had any impact on visibility, and weather remains 'green' as skies are clear above the landing facility's runway |
| 05:46 a.m. | L-:35 | earlier, prior to the tanking process Sunday night, a transient voltage spike was detected in the Fuel Cell 2 pump motor. The fuel cells have been performing as expected ever since. Launch managers discussed the event throughout the night and ultimately cleared the issue for today's launch. It will not be a constraint to liftoff today as the trouble will be investigated prior to Discovery's next mission, STS-133, only |
| 05:56 a.m. | L-:25 | the Eastern Range is reporting 'no-go' due to a failed command message encoder verifier. No word yet on whether this will be an impact to today's scheduled launch. There are no other technical issues currently and weather remains 'go' |
| 05:58 a.m. | L-:23 | the range safety officer just informed NASA Test Director that the system is partially operational and that constraint has been cleared. The Eastern Range is now 'go' |
| 06:00 a.m. | L-:21 | NASA's two solid rocket booster retrieval ships, Liberty Star and Freedom Star, are out in the Atlantic Ocean downrange of the launch site. When the two solid rocket boosters will burn out and fall into the sea below, each ship will close in on one booster's impact point. The parachutes and spent booster casings are retrieved and returned to the Kennedy Space Center |
| 06:07 a.m. | L-:14 | we are at 14 minutes before launch, as the International Space Station, shining brightly in the early morning sky, is passing overhead of Kennedy Space Center. By the time of liftoff, the International Space Station will be about 220 miles over the Atlantic Ocean, southwest of Ireland, and the STS-131 Space Shuttle mission is now poised to begin its chase in 14 minutes |
| 06:11 a.m. | L-:10 | NASA Test Director just polled his team of launch controllers, and all report they are 'go' for liftoff and ready to resume the countdown on time. He informed the Launch Director the team is ready to proceed. The latter, in turn, conducted one last round of polls with upper-level launch managers and gave the Test Director the go-ahead to continue the countdown as he warned the crew too that the flight was 'go' for launch |
| 06:12 a.m. | L-:9 | T-9 minutes and counting! The T-9 minutes built-in hold is now over and no planned holds are left in the countdown, as the ground launch sequencer, or GLS, is in charge of the countdown from now until liftoff. This computer program controls all major milestones, sends hundreds of commands to the shuttle and ground equipment, monitors all critical functions and has the power to stop the countdown if anything appears amiss |
| 06:14 a.m. | L-:7 | orbiter access arm is pulling away from Discovery. It can be returned to the orbiter's side in seconds if necessary |
| 06:16 a.m. | L-:5 | APU prestart 'go'! Orbiter Test Conductor has instructed the mission's pilot to configure Discovery's three auxiliary power units (or APUs) for their start-up in about one minute. |
| 06:17 a.m. | L-:4 | APU start 'go'! By T-minus five minutes and counting, the mission's pilot is flipping switches to start the shuttle's trio of APUs. These hydrazine-fueled generators are located in the Space Shuttle aft end and power the hydraulic systems, which in turn operate the shuttle's main-engine motion and steering surfaces |
| 06:18 a.m. | L-:3 | engine motion and steering surfaces check! the orbiter's rudder and wing flaps are moving through their range of motion to confirm these steering surfaces, called aerosurfaces, are ready to move as required. The check is followed immediately by a main-engine gimbal test, in which the shuttle's three main engines move back and forth to verify they are ready to steer the vehicle as it climbs toward orbit |
| 06:20 a.m. | L-:1 | the STS-131 astronauts have been instructed: 'Close and lock your visors!' and start their oxygen flow. Stable replenish has ended and the External Tank's propellant tanks have reached flight pressure. Cameras on the solid rocket boosters are activated. Gaseous oxygen vent arm is moving away from the top of the External Tank |
| 06:21:04 a.m. | L-:00:31 | at T-31 seconds, the ground launch sequencer gives the 'go' to begin the auto-sequence of final, critical steps leading to liftoff |
| 06:21:19 a.m. | L-:00:16 | sixteen seconds before ignition, a flood of water is released across the surface of the mobile launcher platform and down into the flame trench below. That is the water sound suppression system helps absorb the powerful sound waves created at liftoff |
| 06:21:25 a.m. | L-:00:10 | at T-10 seconds, in anticipation of the three main engines ignition, the free hydrogen burnoff system igniters are firing, creating a shower of sparks beneath Discovery's three main engines |
| 06:21:29 a.m. | L-:00:06 | T-6 seconds. Main engines ignition! As the pressure builds up, the launch stack strains against its hold-down posts, until the solid rocket boosters ignite in turn, signaling launch |
| 06:21:35 a.m. | liftoff | solid rocket boosters ignition and... liftoff! Across the space center and surrounding communities, employees, residents and space fans are watching the launch as the STS-131 mission is now taking off and clearing the tower into the predawn sky, performing the last nighttime liftoff of the Space Shuttle program! It's now the Mission Control Center in Houston which is assuming control of the flight. Astronaut Rick Sturckow, serving as the spacecraft communicator, or CAPCOM, will maintain verbal contact between mission control and the mission's commander aboard Discovery during ascent |
| into the flight | ||
| 6:23 p.m. | :01 | Go at throttle up! The CAPCOM has called the crew for the three main engines throttling up to 104 percent of rated thrust as Discovery is approaching 'max Q,' the area of maximum aerodynamic pressure. The stack engines are accelerating the orbiter to 17,500 mph in just eight and a half minutes. Discovery has performed a roll maneuver, pointing it precisely on the trajectory of 51.6 degrees to catch up to the ISS |
| 6:24 p.m. | :02 | all parameters nominal! All three main engines, fuel cells and auxiliary power units are performing well as the Space Shuttle passes 48 miles in altitude, traveling 4,500 miles per hour. Discovery is rocking Florida's Space Coast, rattling windows, shaking the ground and setting off car alarms nearby, and... solid rocket booster separation! The two solid rocket boosters have burned out and separated right on time and then tumbling down into the ocean. During the climb, the two orbital maneuvering system engines of the orbiter are assisting the three main engines for the ascent |
| 6:26 p.m. | :04 | negative return! The Space Shuttle is now too far downrange and flying too fast to return to the Kennedy Space Center if an engine failure should threaten the flight |
| 6:27 p.m. | :05 | press to ATO. Discovery could now reach a lower-than-planned orbit even without one engine. All three engines are performing well, as are all three auxiliary power units and fuel cells |
| 6:29 p.m. | :07 | press to MECO! CAPCOM calling for the Discovery crew to "press to MECO," meaning that the three main engines are to be shut down. That is to avoid that the External Tank, which is going to separate, goes orbital. At that moment, the orbiter could reach its planned orbit now even if one engine stopped functioning. Discovery has returned to a heads-up orientation, allowing for better communications through the Tracking and Data Relay Satellite system (TDRS) |
| 6:31 p.m. | :09 | main engine cutoff and tank separation! Discovery and the seven STS-131 astronauts have reached a preliminary orbit as the External Tank has been jettisoned and is falling back toward Earth and burning on re-entry |
