Spaceflight is hard and dangerous. United Launch Alliance (ULA) just took the next step in reducing the risk for astronauts by installing a zipline — the Emergency Egress System (ESS) — at their launch pad in Cape Canaveral, Florida. The zipline will allow astronauts and crew to quickly flee from the tower if something goes wrong.
ULA’s new astronaut zipline is part of ongoing developments for NASA’s commercial crew transportation program. When Boeing’s CST-100 Starliner crew capsule blasts off atop ULA’s Atlas V rockets, the zipline will be part of the emergency systems to protect astronauts. If an anomaly happens in the countdown to launch — like a fire in the capsule or an electrical fault in the rocket — astronauts and ground support staff in the tower can use the zipline to flee to safety.
Engineers evaluate the Emergency Egress System that will carry astronauts and ground support staff down 52 meters and out over 400 meters from the Crew Access Tower during an emergency. Credit: NASA/Leif Heimbold
The ziplines were installed by Terra-Nova LLC. The company are creators of recreational ziplines, including the world’s longest zipline stretching 2,545 meters over the hills of Copper Canyon, Mexico. The company modified their recreational system so the harness fits Boeing’s spacesuit design and the brake handles are easier to grab in flight gloves.
The five harnesses on four cables are all independent. “You can load the harness at any time. You can pop and go at any time,” said Terra-Nova owner Eric Cylvick during a telephone interview with NOW.SPACE. “It’s a first-come, first-served egress system.” This is unlike the escape system of the space shuttle era, where the first person to reach the slidewire baskets needed to wait for others before deploying the escape system.
In an emergency, astronauts will exit the spacecraft, feel their way to the zipline, strap themselves into a harness on any of the cables, and zip to safety over 400 meters away at the landing zone. Because the system can deploy harness one after another with no pausing, up four people can flee simultaneously, and up to twenty people to clear the tower as quickly as they can strap into the harnesses. “You can load the harness at any time, and you can pop and go at any time,” said Cylvick.
The steep 14% grade means that escaping personnel will hit a top speed of 65 kilometers per hour in just 30 seconds. They can use a pair of brake-control handles to slow their speed, or nine meters of springs will slow them down if they forget to brake. “The nice attribute of being able to control your own speed,” said Cylvick, “is that you can stop precisely in a specific location at the bottom and get out of the harness very easily.”
Terra-Nova will also install a training system north of the launch tower for personnel to practice their emergency escapes.
While the system didn’t take much modification to meet the needs of astronauts instead of recreational thrill-seekers, it was such an unusual project for Terra-Nova that Cylvic originally thought it was a prank call. “The first time [ULA] called us, they told us not to hang up,” said Cylvick with a laugh. “It was a great project to be involved in. Everyone learned a lot, and it is quite an honor.”
Three engineers test the newly-installed Emergency Egress System from the Crew Access Tower at Space Launch Complex 41 in Florida. Credit: NASA/Leif Heimbold
Once the rockets launch, astronauts will rely on Starliner’s emergency abort system. If anything goes awry, astronauts will eject and parachute to safety.