About Launch Complex 39B | Kennedy Space Center

Launch Complex 39B at NASA’s Kennedy Space Center is a cornerstone of American space exploration. From the Apollo program to the Artemis missions, Launch Complex 39B has been at the forefront of technological advancements. Known for its adaptability, this historic site continues to pave the way for government and commercial space endeavors, offering a glimpse into the future of space exploration.

Quick overview

Built in: Constructed between 1967 and 1968.
Dimensions: Launch Complex 39B spans approximately 1.36 square kilometers (344 acres), slightly larger than Launch Complex 39A. The site includes a launch tower over 370 feet tall, comparable to a 37-story building.
Total launches to date: Launch Complex 39B has supported 60 launches as of January 2025.
Current Operator: NASA currently operates Launch Complex 39B, utilizing it for the Space Launch System (SLS) rocket as part of the Artemis program.
Recent Upgrades: Significant upgrades have been completed at Launch Complex 39B to support the SLS rocket and Orion spacecraft for Artemis missions. These include replacing or upgrading pad subsystems used during the Apollo and Space Shuttle programs.

Key features

Clean pad design: This simplified pad design removes structures specific to individual rockets, reducing turnaround time and supporting diverse launch vehicles.
Crew access arm: Designed for Artemis missions, this retractable bridge allows astronauts to board the Orion spacecraft and includes advanced safety features for quick evacuation if needed.
Mobile launcher integration: Built for NASA’s Space Launch System (SLS), the mobile launcher is adaptable for future rocket designs.
Advanced lightning protection system: Three 600-foot-tall towers safeguard rockets and equipment from Florida’s frequent lightning strikes.

How it all started

Constructed alongside Launch Complex 39A in the 1960s, Launch Complex 39B was originally designed for NASA’s Apollo program. Its first mission, Apollo 10, in 1969, was a full-dress rehearsal for the Moon landing. The pad later supported Skylab missions and the Apollo-Soyuz Test Project.

Notable missions from Launch Complex 39B

The Apollo era: Pioneering space exploration

1969–1975: Launch Complex 39B supported the Apollo 10 mission, a pivotal test of the lunar landing systems that paved the way for the Moon landing. It also hosted Skylab missions, America’s first space station program, contributing significantly to human spaceflight research. The Apollo-Soyuz Test Project launched from here in 1975, symbolizing a groundbreaking collaboration between the U.S. and the Soviet Union.

Space Shuttle program on Launch complex 39B

Space Shuttle: Redefining access to space

1986–2006: Launch Complex 39B was integral to the Space Shuttle program, hosting 53 launches. These included the maiden flight of Challenger (STS-6) and critical missions for assembling the International Space Station (ISS). The pad also played a role in scientific and exploratory missions, furthering NASA’s research objectives.

Ares I-X test flight: A glimpse into future design

2009: The pad supported the Ares I-X test flight, the only launch of NASA’s Constellation program, which aimed to return humans to the Moon. This mission tested new rocket designs and technologies, providing valuable data for future exploration initiatives.

Artemis era: Returning to the Moon and beyond

2022–present: Launch Complex 39B hosted Artemis I, the first uncrewed mission of NASA’s Space Launch System (SLS). This mission marked a significant step toward establishing a sustainable human presence on the Moon. The pad continues to undergo upgrades to support future Artemis missions, which aim to pave the way for human exploration of Mars.

What’s next for Launch Complex 39B

As the cornerstone of NASA’s Artemis program, Launch Complex 39B is set to host missions that will return humans to the Moon and eventually pave the way to Mars. With upgrades to its infrastructure, it is also prepared to support commercial launches, solidifying its position as a multi-purpose launch site for decades to come.

What’s special about Launch Complex 39B

Launch Complex 39B stands out for its versatility and continued role in NASA’s operations. Unlike Launch Complex 39A, which is leased to SpaceX, Launch Complex 39B remains under NASA’s direct management. Its "clean pad" design allows it to support a wide range of launch vehicles, making it a key player in government and commercial missions. The pad’s adaptability remains vital to the Artemis program and future projects.

Additionally, Launch Complex 39B is central to collaborative efforts, bridging the gap between government and commercial space exploration. This synergy strengthens the pad’s role in advancing humanity’s reach into space.

Visiting Launch Complex 39B

Although Launch Complex 39B is not open to the public, the Kennedy Space Center offers the guided Explore Tour, providing a view of the complex from a designated observation area while sharing its history and significance.

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Fun facts about Launch Complex 39B

The pad’s flame trench was redesigned with 1.3 million firebricks to handle the intense heat of modern rocket engines.
Launch Complex 39B’s lightning protection system includes three 600-foot-tall towers, making it one of the tallest lightning protection systems in the world.
The pad fostered international cooperation through the Apollo-Soyuz Test Project in 1975, marking a historic partnership between the U.S. and the Soviet Union.
The clean pad design wasn’t just about functionality—it reduced environmental impact by eliminating the need for massive permanent structures.
Launch Complex 39B is designed to handle rockets for missions that have yet to be conceptualized, making it one of the most forward-looking facilities in the world.

Frequently asked questions about Launch Complex 39B

Where can I see Launch Complex 39B?

You can view Launch Complex 39B at the Kennedy Space Center Visitor Complex, located at Space Commerce Way, Merritt Island, FL 32899. Find out how to get to Kennedy Space Center here.

Can I see Launch Complex 39B up close?

While direct access is restricted, the Kennedy Space Center Visitor Complex’s Explore Tour provides excellent viewing opportunities of Launch Complex 39B. Book Explore Tour here.

What was the first launch from Launch Complex 39B?

The first launch was Apollo 10 in 1969, which served as a dress rehearsal for the Moon landing.

Are Launch Complexes 39B and 39A close to each other?

Yes, Launch Complex 39B and Launch Complex 39A are about 2 miles apart, making it possible to conduct operations at both sites simultaneously when needed. Read more about Launch Complex 39A here.

What rockets currently launch from Launch Complex 39B?

Launch Complex 39B is used primarily for NASA’s Space Launch System (SLS) and the Artemis program. It is also being prepared for potential commercial launches.

What makes this launch complex unique?

Launch Complex 39B’s "clean pad" design supports various launch vehicles, and its management by NASA ensures its adaptability for both government and commercial missions.