Last Flight-Qualified Space Shuttle External Tank Crosses Panama Canal

NASA's last flight-qualified space shuttle external tank
NASA’s last surviving flight-qualified space shuttle external tank is seen at the Panama Canal on April 25. (Image credit: California Science Center/David Knight via

A giant space shuttle fuel tank made for an unusual sight Monday (April 25) at the Panama Canal.

The 154-foot-long (47 meter) external tank, riding atop an uncovered flatbed barge, entered the famous waterway on its journey to the California Science Center in Los Angeles, where it will be displayed with NASA's retired space shuttle Endeavour.

"We're anticipating making the first part of the canal transit, Gatun Locks, on the [afternoon] of the 25th, overnighting in Gatun Lake and then proceeding through the Pedro Miguel Locks and Miraflores Locks on the afternoon of the 26th," Dennis Jenkins, project director for Endeavour's exhibit at the California Science Center, wrote in an email. [Photo Gallery: Shuttle External Tank at Panama Canal]

According to the documentary team filming the transit, the orange-brown external tank entered Gatun Locks at about 12:45 p.m. EDT (1645 GMT; 11:45 a.m. local time).

NASA's last existing flight-qualified example, External Tank 94 (ET-94) began its ocean voyage to the Panama Canal on April 12 — by coincidence, on the 35th anniversary of the first space shuttle launch in 1981. Leaving the Michoud Assembly Facility in New Orleans where it was built some 15 years ago, ET-94 traveled for two weeks to arrive at the canal.

"[The tank has] survived the first part of her historic sea voyage with no issues," Jenkins wrote.

ET-94's next leg will be longer. After transiting the canal's six locks — a water staircase that will lift its barge 85 feet (25 m) to the height of Gatun Lake and then back down to sea level on the Pacific side — the tugboat Shannon Dann will pull the barge, the Gulfmaster I, for the next 17 to 20 days to San Diego.

There, ET-94 will clear customs before its expected arrival at Fisherman's Village in Marina del Rey on May 18.

Webcam view showing the shuttle external tank ET-94 entering the Gatun Locks at the Panama Canal, April 25, 2016. (Image credit:

Two days later, the California Science Center will throw its annual Discovery Ball fundraiser at the marina to celebrate ET-94's arrival and send it on its way on an overnight road trip to its new home. Leaving on a similar but shorter trek than the one Endeavour took in 2012, the external tank will be driven through the streets of Los Angeles to Exposition Park, where the science center is located.

The tank will be parked outside the Samuel Oschin Space Shuttle Pavilion, where Endeavour is on display today, so that workers can make repairs, restore its flight hardware and prepare it to be mated with the orbiter. Together with a pair of solid rocket boosters, ET-94 and Endeavour will be exhibited in a launch pad-like configuration in the Science Center's future Samuel Oschin Air & Space Center, slated to open in 2019.

The vertical display will be the world's only exhibit of a fully authentic space shuttle stack. Guests will be able to rise to the top of the vehicle by way of a gantry-like tower.

ET-94 is the fifth external tank to cross the Panama Canal and the first to do so on an open-air barge. Four previous external tanks, ETs 23, 27, 33 and 34, traveled by covered barge to California in the early 1980s, when plans existed for a shuttle launch pad at Vandenberg Air Force Base.

ET-23 was mated with the orbiter prototype Enterprise for a fit check test at Vandenberg's Space Launch Complex 6 (SLC-6) before the west coast launches were canceled in the wake of the Challenger accident in January 1986.

The four external tanks were subsequently shipped back to the east coast — again by way of the Panama Canal — to launch shuttle missions from the Kennedy Space Center in Florida.

View a photo gallery of external tank ET-94 crossing the Panama Canal at collectSPACE.

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Robert Z. Pearlman Editor, Contributor

Robert Pearlman is a space historian, journalist and the founder and editor of, an online publication and community devoted to space history with a particular focus on how and where space exploration intersects with pop culture. Pearlman is also a contributing writer for and co-author of "Space Stations: The Art, Science, and Reality of Working in Space” published by Smithsonian Books in 2018. He previously developed online content for the National Space Society and Apollo 11 moonwalker Buzz Aldrin, helped establish the space tourism company Space Adventures and currently serves on the History Committee of the American Astronautical Society, the advisory committee for The Mars Generation and leadership board of For All Moonkind. In 2009, he was inducted into the U.S. Space Camp Hall of Fame in Huntsville, Alabama. In 2021, he was honored by the American Astronautical Society with the Ordway Award for Sustained Excellence in Spaceflight History.