STS-88 was the first Space Shuttle mission to the International Space Station (ISS). It was flown by Space Shuttle Endevour and took the first American module, the Unity mode to the station.

The seven-day mission was highlighted by the mating of the U.S.-built Unity node to the Functional Cargo Block(Zarya module) already in orbit, and three spacewalks to connect power and data transmission cables between the Node and the FGB. Zarya, built by Boeing and the Russian Space Agency, was launched on a Russian Proton rocket from the Baikonur Cosmodromein Kazakhstan in November 1998.

Other payloads on the STS-88 mission included the IMAX Cargo Bay Camera (ICBC), the Argentine Scientific Applications Satellite-S (SAC-A), the MightySat 1 Hitchhiker payload, the Space Experiment Module (SEM-07) and Getaway Special G-093 sponsored by the University of Michigan.

Launch attempts
13 Dec 1998, 3:58:19 amscrubbed—procedural (T-0:19)40% Weather -Master alarm due to hydraulic problem
24 Dec 1998, 3:35:34 amsuccess0 days, 23 hours, 37 minutes

Node 1, named Unity, was the first space station hardware delivered by the Space Shuttle. It has two Pressurized Mating Adapters (PMA), one attached to either end. One PMA (PMA-1) is permanently mated to Zarya, and the other (PMA-2) is used for orbiter dockings and crew access to the station. Unity also contains an International Standard Payload Rack used to support on-orbit activities, which was activated after the fifth Shuttle/Station assembly flight.

To begin the assembly sequence, the crew conducted a series of rendezvous maneuvers similar to those conducted on other Shuttle missions to reach the orbiting FGB. On the way, Currie used the Shuttle's robot arm to place Node 1 atop the Orbiter Docking System. Cabana completed the rendezvous by flying Endeavour to within 10 metres (33 ft) of the FGB, allowing Currie to capture the FGB with the robot arm and place it on the Node's Pressurized Mating Adapter. Once the two elements were docked, Ross and Newman conducted two scheduled spacewalks to connect power and data cables between the Node, PMAs and the FGB.[8] The day following the spacewalks, Endeavour undocked from the two components, completing the first Space Station assembly mission.
Endeavour's astronauts toured the new International Space Station on Thursday, 10 December 1998, entering the Unity and Zarya modules for the first time, and establishing an S-band communications system that enables U.S. flight controllers to monitor the outpost's systems. Reflecting the international cooperation involved in building the largest space complex in history, Commander Robert Cabana and Russian Cosmonaut Sergei Krikalev opened the hatch to the U.S.-built Unity connecting module and floated into the new station together.

The rest of the crew followed and began turning on lights and unstowing gear in the roomy hub to which other modules would be connected in the future. Each passageway within Unity was marked by a sign leading the way into tunnels to which new modules would later be connected.
About an hour later, Robert Cabana and Sergei Krikalev opened the hatch to the Russian-built Zarya control module, which was the nerve center for the station in its embryonic stage. Joined by Pilot Frederick Sturckow and Mission Specialists Jerry Ross, James H. Newman and Nancy Currie, Cabana and Krikalev hailed the historic entrance into the International Space Station and said the hatch opening signified the start of a new era in space exploration.

Krikalev and Currie replaced a faulty unit in Zarya which controlled the discharging of stored energy from one of the module's six batteries. The battery had not been working properly in its automatic configuration, but the new unit was functioning normally shortly after it was installed.

The astronauts also unstowed hardware and logistical supplies stored behind panels in Zarya, relocating the items for use by the Shuttle crew that was to visit the station in May 1999 and by Shepherd's expedition crew. The astronauts also completed their initial outfitting of the station.

The hatches to Zarya and Unity were closed before Endeavour undocked from the new station, leaving the new complex to orbit the Earth unpiloted.