STS-131

STS-131 was a NASA Space Shuttle mission to the International Space Station. launched on April 5, 2010, at 6:21 am from LC-39A, and landed at 9:08 am on April 20, 2010, on runway 33 at the Kennedy Space Center's Shuttle Landing Facility. The mission marked the longest flight for Space Shuttle Discovery and its 38th and penultimate flight.
The primary payload was a Multi-Purpose Logistics Module loaded with supplies and equipment for the International Space Station. The mission also removed and replaced an ammonia tank assembly outside the station on the S1 truss. STS-131 furthermore carried several on-board payloads; this mission had the most payloads since STS-107. It is also the last shuttle mission with a crew of 7.

Crew

Crew seat assignments

Mission payload

Multi-Purpose Logistics Module ''Leonardo''

The primary payload of STS-131 was the Multi-Purpose Logistics Module Leonardo. The MPLM was filled with food and science supplies for the International Space Station. The MPLM also carried the third and final Minus Eighty Degree Laboratory Freezer for ISS, Window Orbital Research Facility, one Crew Quarters Rack, the Muscle Atrophy Resistive Exercise rack, Resupply Stowage Racks, and Resupply Stowage Platforms.

Lightweight Multi-Purpose Equipment Support Structure Carrier

The Lightweight Multi-Purpose Equipment Support Structure Carrier carried a refurbished Ammonia Tank Assembly to the ISS. The refurbished ATA was removed from the Space Station and returned for use on this mission during STS-128. It was swapped with an empty tank which will ride home on the LMC.
Image:14 LMC STS-131.jpg|thumb|right|LMC with ATAs STS-131. Note that the MISSE-6 FSE return was deferred to STS-133.

Location	Cargo	Mass
Bays 1–2	Orbiter Docking System EMU 3008 / EMU 3017	~
Bay 4P	Shuttle Power Distribution Unit	~
Bay 7S	ROEU 751A umbilical
Bays 7–12	Leonardo
Bay 13	Lightweight MPESS Carrier
Starboard Sill	Orbiter Boom Sensor System
Port Sill	Canadarm
	Total:

TriDAR

This mission was the second flight of the TriDAR, a 3D dual-sensing laser camera, intended for potential use as an autonomous rendezvous and docking sensor. TriDAR provides guidance information that can be used to guide a vehicle during rendezvous and docking operations in space. TriDAR does not rely on any reference markers, such as reflectors, positioned on the target spacecraft. To achieve this, it relies on a laser based 3D sensor and a thermal imager. Geometric information contained in successive 3D images is matched against the known shape of the target object to calculate its position and orientation in real-time. The TriDAR tracked the ISS position and orientation from the shuttle during docking, undocking, and flyaround operations.

Mission milestones

The mission marked:

162nd NASA crewed space flight
131st shuttle mission since STS-1
38th flight of Discovery
33rd shuttle mission to the ISS
106th post-Challenger mission
18th post-Columbia mission
35th and last night launch of a shuttle, 22nd night launch from launch pad 39A
2nd "descending node" entry since 2003
Shuttle processing

Space Shuttle Discovery was moved from its hangar in the Orbiter Processing Facility 3 to the nearby Vehicle Assembly Building on February 22, 2010. The rollover was completed around 10:30 EST. According to NASA, the rollover occurred a day earlier than announced to take advantage of favorable weather in advance of poor conditions forecasted on the next day.
An earlier plan to move Discovery into the VAB on February 12, 2010, was delayed because of cold weather at the Kennedy Space Center. For the rollover, temperatures in the VAB had to be above for more than twelve hours because Discovery was not attached to any heating purges to protect its systems from potential damage from the cold.
Space Shuttle Discovery began its trip, known as the rollout, to LC-39A at 23:58 EST on March 2, 2010. The complete shuttle stack and mobile launcher platform were secured to the LC-39A structure at 6:49 EST on March 3, 2010. The trek took 6 hours 51 minutes to complete. The rollout was delayed 24 hours by the threat of lightning from a passing cold front. That weather moved away, and the stiff wind gusts blowing on Florida's Space Coast on the next day were not a factor for the rollout. Ahead of the rollout, engineers noticed some damage caused by birds to the External Tank, which was repaired inside the VAB. Birds had managed to reach the tank, and pecked away at the Thermal Protection System foam.

Mission timeline

April 5 (Flight Day 1 – Launch)

Discovery lifted off successfully at 06:21 EDT, marking this launch as the last night launch in the Space Shuttle program. After the 8 1/2-minute ride to space, Discovery's seven person crew began configuring the orbiter from a launch vehicle to an orbital vehicle. Commander Alan Poindexter and pilot Jim Dutton, with help from mission specialist 2 Dorothy Metcalf-Lindenburger, also performed a series of engine firings or burns to adjust their speed and refine their path to the International Space Station. While the engine burns were going on, the rest of the crew opened the payload bay doors, set up the computers and K_u band antenna. The antenna suffered a failure during normal checkout and setup on orbit. Due to the failure, the normal downlink of imagery of the external tank was not completed. The crew on board will monitor the inspections of the thermal protection system in real time and will note any spots of interest and let the ground know while downlinking the imagery after docking. The dish antenna also serves as a radar antenna, measuring the distance to the space station.

April 6 (Flight Day 2 – Inspections)

The seven person crew of STS-131 was awakened to begin their first full day in space on Flight Day 2. Due to the lack of K_u-band communication, changes to the crews daily plan were read up for them to write out. After their post sleep activities, commander Alan Poindexter and pilot Jim Dutton fired Discovery's Orbital Maneuvering System engines to correct and further refine the shuttle's path to the ISS. Astronauts Naoko Yamazaki and Dorothy Metcalf-Lindenburger began activating and checking out the Shuttle Remote Manipulator System also known as the Canadarm. While Metcalf-Lindenburger and Yamazaki were working with Canadarm, Stephanie Wilson was getting equipment together and set up to record the inspections of the shuttle's heat shield. The inspections were recorded so they could be downlinked to the ground once docked to the ISS. Once all that work was done, commander Poindexter and pilot Dutton joined Metcalf-Lindenburger, Yamazaki, and Wilson to conduct the inspection of the shuttle's heat shield. While the inspection was going on, Rick Mastracchio and Clayton Anderson were on the mid-deck of Discovery checking out the Extravehicular Mobility Units and getting them ready for their three spacewalks. The last portion of the crew day was spent preparing and checking out all of the tools used during rendezvous.

April 7 (Flight Day 3 – Docking)

Space Shuttle Discovery successfully docked with the space station at 07:44 UTC on April 7, 2010, as the two spacecraft sailed 220 miles above the Caribbean. The crew performed six successful engine firings to set up the on-time docking. Prior to docking commander Poindexter guided Discovery through the standard Rendezvous Pitch Maneuver. Station commander Oleg Kotov and flight engineer T.J. Creamer took more than 350 photos of Discovery's heat shield. Once Discovery docked to the International Space Station, a series of leak checks were done on both sides of the hatch by the shuttle and station crews. The hatches between the two vehicles were opened at 09:11 UTC, which was 30 minutes earlier than planned. Once the hatches were opened the STS-131 crew got a safety briefing from the station crew, then began to transfer items that would be needed for later in the day and early on flight day 4. Two items that were transferred were the two EMUs that will be used for the three spacewalks. The crew also completed a grapple of the Orbiter Boom Sensor System with the Space Station Remote Manipulator System also known as Canadarm2. Once the OBSS was grappled it was unberthed from the starboard sill of the space shuttle payload bay, and handed off to the SRMS. Throughout the day, after docking to the station, the shuttle crew began downlinking all of the inspection video from flight day 2, and launch imagery and video.

April 8 (Flight Day 4 – MPLM ingress)

On flight day 4, Stephanie Wilson and Naoko Yamazaki grappled and berthed the Multi-purpose Logistics Module Leonardo. The MPLM was berthed to the station at 04:24 UTC. The hatches were opened by station flight engineer Soichi Noguchi and shuttle mission specialist Clayton Anderson at 11:58 UTC. The joint STS-131/Expedition 23 crews began transferring cargo from the MPLM, with the first item being a Rate Gyro Assembly which will be replaced on the first spacewalk of the mission. During flight day 4, commander Alan Poindexter did several in-flight interviews. Commander Poindexter was joined by mission specialists Rick Mastracchio and Stephanie Wilson. The interviews were with the Tom Joyner Radio Show, WVIT-TV and Fox News Radio. At the end of the day, Mastracchio and Anderson entered the Quest airlock and begin breathing pure oxygen for an hour, while the atmospheric pressure inside the airlock was lowered to 10.2 psi. This procedure is known as the pre-breathe protocol and is done before every spacewalk, to purge nitrogen from the blood stream and prevent decompression sickness.