STS-124 was the 35th mission of Space Shuttle Discovery. It went to the International Space Station on this mission. Discovery launched on May 31, 2008, at 17:02 EDT, moved from an earlier scheduled launch date of May 25, 2008, and landed safely at the Kennedy Space Center's Shuttle Landing Facility, at 11:15 EDT on June 14, 2008. Its objective was to deliver the largest module of the space station – Kibō, the Japanese Experiment Module pressurized section. The mission is also referred to as ISS-1J by the ISS program.

"I'm really fortunate to be given the crew members that I have on this mission. It's myself and six others. We do swap one of our crew members with the expedition crew member on board. So Greg goes up, Greg stays on station and Garrett comes home. But the crew that was assigned to me—I'm really fortunate to have some really talented people. Ken Ham, as a pilot, knows the orbiter better than anybody I've seen. This is his first flight. My lead EVA crew member is Mike Fossum who did three spacewalks on my previous flight, STS-121. We've flown together before. I have all the confidence in the world in his ability to execute these EVAs. Karen Nyberg, my MS1, sits on the flight deck for ascent and entry. She's also the lead for all the robotic arm operations. She'll be flying three robotic arms in space, incredibly motivated, well ahead of the game and I expect great things from her. Ron Garan is my flight engineer, a colonel in the Air Force. This is going to be his first time in space as well as is Karen's and Ken's and he's doing three spacewalks. So he's got a lot on his plate. He's been doing great during training and he's going to have the opportunity to prove himself during these three spacewalks. I kind of wish it was me getting to go outside. I can't do that, but we expect great things from Ron as well. And then I have Aki Hoshide, our Japanese crew member, who grew up in New Jersey kind of like me. That's an interesting thing about our flight—we have four people from New Jersey on the mission. I look at Aki as the payload commander. He is responsible for that Japanese laboratory and he has taken on that responsibility as completely as I could have hoped for. All through our training he's been very much focused on the Japanese lab, making sure it's ready to go, making sure we're completely trained on the systems and everything we have to do. I've given him a lot of responsibility and he's completely taken it on."

STS-124 delivered the Pressurized Module (PM) of the Japanese Experiment Module (JEM), called Kibō, to the International Space Station (ISS). Kibō was berthed to the Harmony module and the pressurized section of the JEM Experiment Logistics Module, brought up by the STS-123 crew, was moved from Harmony to the JEM-PM. The Japanese Remote Manipulator System, a robotic arm, was also delivered by STS-124 and attached to Kibō. The entire Kibō laboratory was brought up over three missions. All the modules were manufactured at the Tsukuba Space Center and were shipped to the KSC SSPF for launch processing. It is manufactured from stainless steel and titanium.

Discovery carried with it replacement parts in a mid-deck locker for a malfunctioning toilet on the International Space Station. The crew had been using other facilities for waste until the new replacement parts were installed on the Zvezda module of the ISS.

Flying with the STS-124 crew was an action figure of Buzz Lightyear, a fictional character in the Toy Story franchise. Ken Ham, pilot of the STS-124 mission, brought with him episodes of ESPN Radio's Mike and Mike in the Morning, and a plastic microphone stand with the ESPN logo on it. Along with those, a yellow jersey from Lance Armstrong's record-setting seven victories at the Tour de France bicycle race, the backup jersey Eli Manning took to the Super Bowl, and the last jersey that American Major League Baseball's Craig Biggio wore in a game were placed inside the orbiter's lockers.

With the completion of STS-124, the next permanent pressurized module would not be delivered to the ISS by a Space Shuttle until STS-130 brought up Tranquility in February 2010.

The mission marked:

On April 26, 2008 Discovery was rolled over to the Vehicle Assembly Building (VAB) from its processing bay in the Orbiter Processing Facility. Once in the VAB it was lifted vertically and mated with its external tank and solid rocket boosters on April 28, 2008. At the end of a week-long prep schedule on May 2, 2008, at 23:47 EDT the stack was rolled out to launch pad 39A on top the Mobile Launch Platform. Carried by the Crawler Transporter, Discovery arrived and was secured at LC-39A on May 3, 2008, at 06:06 EDT. The payload canister containing the JEM was rolled out to the Payload Changeout Room at the pad on April 29, 2008, and was later installed into Discovery's payload bay on May 5, 2008. The STS-124 crew arrived at Kennedy Space Center on May 6, 2008, for the 3-day Terminal Countdown Demonstration Test and returned to Johnson Space Center on May 9, 2008, after completion of the launch dress rehearsal. After many flight readiness review tests, Discovery was given a go for a May 31, 2008, launch. Discovery launched on May 31, 2008, at 21:02 UTC.