STS-120
STS-120 was a Space Shuttle mission to the International Space Station that launched on October 23, 2007, from the Kennedy Space Center, Florida. The mission is also referred to as ISS-10A by the ISS program. STS-120 delivered the Harmony module and reconfigured a portion of the station in preparation for future assembly missions. STS-120 was flown by, and was the twenty-third Space Shuttle mission to the ISS. It was Discovery's 34th flight.
Crew
Crew notes
As commander of STS-120, Pamela Melroy became the second woman to command a Space Shuttle mission. Additionally, the Expedition 16 crew that received STS-120 was commanded by Peggy Whitson, the first female ISS commander. The flight of STS-120 thus became the first time two female mission commanders were in space at the same time.Crew prior to the Space Shuttle ''Columbia'' disaster
Prior to the Space Shuttle Columbia disaster, the original crew manifest for STS-120 was:The STS-120 mission patch was designed by Michael Foreman before he was reassigned to STS-123.
Mission payloads
| Location | Cargo | Mass |
| Bay 1–2 | Orbiter Docking System EMU 3010 / EMU 3017 | |
| Bay 3P | Shuttle Power Distribution Unit | ~ |
| Bay 4S | SASA FSE | ~ |
| Bay 5P | Power/Data Grapple Fixture for Node 2 | ~ |
| Bay 6S | Main Bus Switching Unit and adapter | |
| Bay 7P | Shuttle Power Distribution Unit | ~ |
| Bay 8–12 | Harmony | |
| Sill | OBSS 203 | ~ |
| Sill | RMS 301 | ~ |
| Total: |
''Harmony'' (Node 2)
STS-120 delivered launch package 10A to the International Space Station. It consisted of the U.S. Harmony module, with four DC-to-DC Converter Unit racks and three Zero-g Storage Racks installed; a Power and Data Grapple Fixture for the station's robot arm, and a Shuttle Power Distribution Unit. Harmony was manufactured for NASA by Thales Alenia Space in Turin, Italy, as part of an agreement between NASA and the European Space Agency and was the first pressurized habitable module delivered to the station since the Pirs docking compartment was installed in August 2001.Since STS-120 docked to the Pressurized Mating Adapter-2 on the forward port of the Destiny module, installation of Harmony occurred in two stages: STS-120 installed Harmony to the port node of the Unity module. After Discovery undocked, the station's robotic arm detached PMA-2 from Destiny, and moved it to the forward port of Harmony. Following the relocation of PMA-2, the robotic arm was used to move Harmony from its initial position to its final position, on the forward port of Destiny.
The final positioning of Harmony allowed for the later installation of the European Columbus and Japanese Kibō research modules, which were attached to the side ports of Harmony.
P6 relocation
During STS-120, the P6 solar arrays were moved from the Z1 truss on top of Unity, to their final position at the port end of the truss.Outreach
STS-120 carried the signatures of over 500,000 students that participated in the 2007 Student Signatures in Space program, jointly sponsored by NASA and Lockheed Martin. In celebration of Space Day in May 2007, students from over 500 schools around the world signed giant posters. Their signatures were scanned onto a disk, and the disk was manifested on the STS-120 mission.Also during STS-120, the lightsaber used by actor Mark Hamill in the 1983 film Return of the Jedi was flown to the station and returned to Earth. Stowed on-board Discovery for the length of the mission, the prop was flown in honor of the 30th anniversary of the Star Wars franchise. On August 28, 2007, Chewbacca from the Star Wars films presented the lightsaber to NASA officials from Space Center Houston, in an official ceremony at Oakland International Airport. The lightsaber was then flown to Houston, where it was greeted by Stormtroopers. The lightsaber will be displayed at Space Center Houston.
Crew seat assignments
Mission background
At the time of the Columbia disaster, STS-120 was scheduled for early 2004. It was delayed repeatedly until October 23, 2007.NASA originally scheduled the launch for October 20, 2007, but due to the International Space Station program requirement, launch was delayed to October 23, 2007.
In light of the small gouge to the underside of Endeavour that occurred on STS-118, in August 2007, NASA managers announced that they expected to add a fifth spacewalk to the STS-120 mission, designed to test a heat-shield repair tool. The repair technique was originally scheduled for a flight in 2008, but following STS-118, it was decided to move up the testing. The repair tool, called a TPS repair ablator dispenser, has never been tested in space, so the spacewalk would have allowed managers to evaluate its effectiveness in low gravity environments. During the course of the mission, issues with the S4 starboard Solar Alpha Rotary Joint, and P6 Solar Array, deferred this test objective to a future mission.
The mission marked:
- 151st NASA crewed spaceflight
- 120th Space Shuttle flight since STS-1
- 34th flight of Discovery
- 95th post-Challenger mission
- 7th post-Columbia mission
Mission timeline
Launch preparations
Following STS-118 in August 2007, NASA managers decided to make modifications to the external tank to be used on STS-120, and modify the liquid oxygen feed-line brackets. The change involved a new low-density foam application, and thinner gaskets. Shuttle Program Managers decided to do this to reduce the foam loss from the area that had been noted since STS-114's "Return to Flight" mission in 2005. STS-118 had a small gouge on the belly of the orbiter due to a chunk of foam that impacted during launch in August 2007. The week of September 17, 2007, NASA managers decided to delay Discovery's rollover to the Vehicle Assembly Building, due to a hydraulic fluid leak from the right main landing gear strut. The strut repair was successfully completed on September 19, 2007. Discovery then moved to the VAB, and was mated to the External Tank and Solid Rocket Boosters. Perched atop the mobile launcher platform, Discovery arrived at Launch complex 39A on September 30, 2007.The crew of STS-120 arrived at Kennedy Space Center on October 7, 2007, and began final preparations, including the terminal countdown demonstration test, or "Dress Rehearsal", scheduled for October 7, 2007, through October 10, 2007.
On October 9, 2007, NASA's Engineering and Safety Center, an independent review group set up after the 2003 Columbia disaster, advised replacement of three of Discovery's reinforced carbon-carbon panels on the leading wing edge, due to a loss of small amounts of the protective silicon-carbide coating. NASA reviewed the issue of oxidation of the panels for several months, using a variety of specialized testing methods, including thermography. These tests showed that the panels had not worsened over the course of the past two flights of Discovery, and the orbiter project engineers concluded in August that Discovery was safe to launch as is. Had a decision been made to repair the panels, the orbiter would have been rolled back to the VAB, delaying the launch.
On October 16, 2007, NASA Managers completed the Flight Readiness Review, and held a press conference to announce the mission plan. The issue of the RCC panels raised by NESC was found to be of little immediate concern, because the NESC took pre-flight thermography data from Endeavour and compared it with Discovery, but there was no commonality in flight history between the two vehicles. The research showed no significant difference between the panels prior to STS-114, and the panels today, which indicates the coating has not worsened during the previous flights, adding confidence that Discovery's RCC panels have had no deterioration in the flights since. NASA announced on the main shuttle page that "The Space Shuttle Program has determined that Discovery's astronauts can safely carry out their mission without having to replace the panels."