People always guess. If you ask a random person on the street how many times that iconic white-and-black bird flew into the blackness of space, they’ll usually throw out a number like fifty, or maybe "a couple dozen." They're off. Way off. To really understand the scale of what NASA pulled off between 1981 and 2011, you have to look at the hard data.
How many shuttle missions were there?
The answer is 135.
That’s it. One hundred and thirty-five times, a crew sat on top of millions of pounds of explosive fuel, shook violently for eight and a half minutes, and ended up in low Earth orbit. It sounds like a lot until you realize it spanned thirty years. That’s an average of about four or five launches a year, though the tempo swung wildly depending on politics, budgets, and, tragically, whether or not a vehicle had recently been lost.
The Five Orbiters That Made It Happen
Most people remember Discovery or Endeavour. But the fleet was a specific, rotating cast of characters. You had Columbia, the heavyweight pioneer that first proved the concept in April 1981. Then came Challenger, which was originally a structural test article before being upgraded for flight. Discovery arrived next, eventually becoming the fleet leader with 39 successful missions under its belt—the most of any orbiter. Atlantis followed, and finally Endeavour, which was built from spare parts to replace Challenger.
Wait. What about Enterprise?
People forget Enterprise. It looked exactly like the others. It had the tiles, the wings, the cockpit. But it never went to space. It didn't even have an engine or a functional heat shield. NASA used it for "Approach and Landing Tests" (ALT) in the late seventies, dropping it from the back of a modified Boeing 747 to see if a brick with wings could actually glide to a runway. It could. But when it comes to the official tally of how many shuttle missions were there, Enterprise doesn't count toward the 135.
The Tally of Triumph and Tragedy
The missions weren't just joyrides. They were grueling, complex construction projects. Early on, the focus was on satellite deployment. Think back to the eighties; the Space Shuttle was basically a high-tech delivery truck. It hauled communication satellites for private companies and top-secret payloads for the Department of Defense.
Then came the Hubble Space Telescope in 1990.
That single mission, STS-31, changed everything. Even though the telescope initially had a "blurry eye," the shuttle was the only vehicle in existence that could go back up, grab it, and fix it. We did that five times. If the shuttle hadn't existed, Hubble would be a multi-billion dollar piece of space junk today. Instead, it’s arguably the most important scientific instrument ever built.
But you can't talk about the 135 missions without talking about the two that didn't come home.
Challenger (STS-51-L) in 1986 and Columbia (STS-107) in 2003. When people ask how many shuttle missions were there, they are often trying to reconcile the success of the program with these two catastrophic failures. Out of 135 missions, 133 landed safely. In the world of experimental aerospace, that's a 98.5% success rate. In the world of human lives, it was a heavy price to pay. The program paused for years after each accident. Engineers went back to the drawing board. They redesigned the O-rings. They obsessed over the foam insulation on the external tank. These pauses are why the total number isn't much higher.
Why the Missions Varied So Much
Every mission had a "STS" designation. That stands for Space Transportation System. You’d think they’d be numbered 1, 2, 3... and so on.
NASA made it confusing.
In the mid-eighties, they switched to a weird coding system. STS-41-B, for example. The "4" stood for the fiscal year, the "1" stood for the launch site (Kennedy Space Center), and the "B" meant it was the second scheduled launch of that year. It was a bureaucratic nightmare that even the astronauts hated. They eventually went back to sequential numbering, but the sequence was already messed up because missions were frequently delayed or swapped. So, STS-135 was the final mission, but it wasn't necessarily the 135th mission planned; it just happened to be the one that turned out the lights.
Breaking Down the 135 Flights by the Numbers
If you look at the logs, the distribution of these 135 flights reveals what NASA was actually doing with its time.
- Department of Defense (DoD): 11 missions. These were mostly "classified." The astronauts couldn't even tell their families what they were doing up there. We know now they were deploying massive spy satellites to keep tabs on the Soviet Union.
- International Space Station (ISS) Assembly: 37 missions. This was the "Construction Era." The shuttle was the only thing capable of carrying the massive modules that make up the ISS. Without the shuttle's robotic arm and its huge cargo bay, the station wouldn't exist.
- Mir Dockings: 9 missions. Believe it or not, we used the shuttle to visit the old Russian space station, Mir. It was a gesture of post-Cold War cooperation that paved the way for the ISS.
- Science and Spacelab: Dozens of missions. Sometimes the cargo bay stayed closed, and the crew spent two weeks inside a pressurized module doing biology and physics experiments in zero gravity.
The variety is staggering. One week they’re launching a probe to Jupiter (Galileo), the next they’re catching a malfunctioning satellite with their bare hands—literally. On STS-49, three astronauts stood in the cargo bay and grabbed a 4-ton satellite because the mechanical capture tool failed. You don't see that kind of grit in modern autonomous spaceflight.
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The Cost of the "How Many" Question
Critics love to point out that the shuttle never met its original goal. In the 1970s, NASA told Congress the shuttle would fly 50 times a year. They promised it would be cheap and routine, like a bus.
It was never a bus.
It was a hand-crafted, temperamental Ferrari. Each mission cost hundreds of millions of dollars—some estimates say over a billion per flight if you factor in the total program development. The complexity was the problem. The Main Engines (RS-25) were engineering marvels, but they required a complete teardown after every flight. The thermal tiles were fragile. Thousands of them had to be inspected by hand.
When you ask how many shuttle missions were there, the number 135 represents a massive compromise between the dream of frequent space travel and the reality of 1980s technology. We couldn't fly it every week. We could barely fly it every month.
The Last Hurrah: STS-135
The final mission took place in July 2011. Atlantis was the bird. It was a four-person crew, the smallest in years, meant to be a lean "logistics" run to stock up the ISS before the fleet retired. When those wheels stopped on the runway at Kennedy Space Center, it wasn't just the end of a mission. It was the end of an era where humans flew into space on a glider.
Since then, we’ve moved to capsules. SpaceX Dragon, Boeing Starliner, and NASA’s own Orion. Capsules are safer. They’re easier to heat-shield. They’re "simpler." But they lack the sheer capability of the shuttle. A capsule can't go up, grab a satellite, bring it into a garage-sized bay, fix it, and put it back. Or bring it home to Earth.
Surprising Facts Most People Miss
- The "Longest" Mission: STS-80 lasted 17 days, 15 hours. Columbia stayed up there doing science while most missions only lasted about 10-12 days.
- The "Shortest" Mission: STS-2 was cut short because of a fuel cell failure. It only lasted 2 days and 6 hours.
- The Most Passengers: Usually, the crew was 7. But on STS-61-A, eight people squeezed in.
- The "Oldest" Astronaut: John Glenn went back up at age 77 on STS-95. It was partly for science (studying aging) and partly for the sheer legend of it.
Actionable Insights for Space Enthusiasts
If you want to dive deeper than just the "135" number, there are specific ways to experience the history of these missions today.
- Visit the Survivors: You can see the actual orbiters. Discovery is at the Udvar-Hazy Center in Virginia. Atlantis is at Kennedy Space Center in Florida (it's displayed as if it's still in orbit, which is breathtaking). Endeavour is at the California Science Center in LA. Enterprise is in NYC at the Intrepid Museum.
- Read the Logs: NASA maintains a "Space Shuttle Mission Summary" pdf that is public domain. It lists every single payload, every spacewalk (EVA), and every "first" for all 135 flights.
- Watch the Re-entries: While launches are flashy, the shuttle’s return was a scientific miracle. It had to hit the atmosphere at 17,500 mph and bleed off that heat without engines. Look up "shuttle plasma footage" to see what the astronauts saw through the windows.
- Listen to the Audio: The "comm loops" from the missions are archived. Hearing the calm voices of Mission Control during a crisis gives you a much better sense of the stakes than any Hollywood movie ever could.
The Space Shuttle was flawed. It was expensive. It was dangerous. But it was also the most versatile machine humans have ever built. Those 135 missions defined three decades of human ambition. They built the ISS, they unlocked the secrets of the universe through Hubble, and they taught us exactly how hard it is to make space travel "routine."
The number isn't just a statistic; it’s a record of 135 times we dared to leave the planet in a ship that could fly home and land on a runway like a plane. We haven't done anything like it since.
Next Steps for Further Exploration:
To truly grasp the technical complexity of these flights, your next step should be researching the Space Shuttle Main Engine (SSME). It was the first "reusable" rocket engine ever made, and its design is still being used today in the SLS rockets going back to the moon. Look for the "RS-25 technical specifications" to see how they managed to keep those engines from melting during the 135 missions.