What Is a Dry Run?
On Tuesday, the four astronauts of Crew-13—NASA’s Jessica Watkins and Luke Delaney, Canada’s Joshua Kutryk, and Russia’s Sergey Teteryatnikov—went through the precise motions of launch day. They donned their sleek SpaceX suits, performed critical air
leak checks, and traveled to the launch pad at Cape Canaveral Space Force Station. There, they boarded the Crew Dragon 'Grace' capsule perched atop the Falcon 9 rocket that will propel them to the International Space Station (ISS). This entire sequence is known as a “dry dress rehearsal.” The “dry” signifies that the rocket is not filled with its cryogenic propellants, making it a safe but incredibly detailed simulation of the real countdown. It’s the final exam for the crew and ground teams before the real test.
A Symphony of Synchronization
While the astronauts are the public face of the mission, the dry run is just as crucial for the hundreds of people in launch control. It’s a full-scale test of communications, procedures, and timelines, ensuring every team member, from the launch director to the pad technicians, knows their role intimately. Think of it as a symphony orchestra rehearsing not just their individual parts, but their timing and coordination. Every cue must be perfect. The teams practice the entire countdown sequence, checking off milestones as if it were the real thing. This synchronization ensures that on launch day, the complex machine of human expertise and rocket hardware operates as a single, flawless unit. Any hesitation or miscommunication is identified and ironed out here, long before it could pose a risk during a live launch.
Rehearsing for the Unexpected
A key part of any dress rehearsal is practicing what to do when things go wrong. While a “wet dress rehearsal”—which includes fueling the rocket—is where teams often practice holds and scrubs in the final minutes of the countdown, the dry run solidifies the crew's emergency procedures. The astronauts meticulously rehearse their actions for every conceivable off-nominal scenario. This is the “more than a rehearsal” aspect in its starkest form. It’s a life-saving drill that builds muscle memory for situations they hope to never encounter. This focus on safety and preparedness is a cornerstone of NASA’s commercial crew partnership with SpaceX, a program that has now flown over a dozen crewed missions to the ISS.
The Mental Countdown
For the astronauts, the dry run is also a profound psychological milestone. After years of training, this is the moment when the mission becomes tangibly real. For the three first-time flyers on Crew-13—Delaney, Kutryk, and Teteryatnikov—it's their first time walking through the launch sequence in full gear, at the pad, and inside the actual spacecraft that will take them to orbit. For commander Jessica Watkins, it’s a familiar process, as she becomes the first NASA astronaut to launch on a Crew Dragon for a second time. This final practice helps them mentally prepare for the G-forces, the vibrations, and the intense focus required for their record-setting, less-than-eight-hour journey to the space station.
Paving the Way for Science in Orbit
Ultimately, the precision of the dry run serves a grander purpose: a six-month science mission aboard the orbiting laboratory. The Crew-13 astronauts will join Expedition 75 and conduct a vast array of research. Their work includes studying how stem cell-derived tissues model diseases like Parkinson's and heart disease, exploring crop production for future deep-space missions, and testing new medical diagnostic equipment. They will also continue studies into Spaceflight-Associated Neuro-ocular Syndrome, a condition that can affect astronauts' vision on long-duration missions. Every procedure perfected during the dry run is a step toward ensuring these vital experiments—which benefit life on Earth and prepare for future journeys to the Moon and Mars—can be carried out successfully.
