Ask the Astronaut: Which is more fun, the ascent into orbit or the reentry?

STS-122 launch.jpg
Launch of the STS-122 shuttle mission from Cape Canaveral. Re-entry is quieter, but more spectacular visually.

Q: Which is more fun, the ascent into orbit or the reentry from space to landing? (Gordon Krauter, Livermore, California)

My reentry experiences were unquestionably more visually exciting than launch, for several reasons. During launch, our shuttle flight deck windows were pointed up at the empty sky, so we saw only a gradual transition from blue to black, with only a split-second of flame visible during booster separation. During reentry, these same windows revealed amazing views of the rapidly approaching Earth and the technicolor light show produced when our spacecraft collided with air molecules in the Earth’s atmosphere. The glowing plasma, ranging from cherry red to light orange to purple and brilliant white in color, was visible through our front, side, and top windows for more than twenty minutes.

During the first two minutes of a shuttle launch, heavy vibration and the howl of the engines made for an exhilarating ride. These were the most exciting moments of our ride to orbit, when you could physically feel the power of our shuttle’s three main engines and two mammoth boosters, subjecting us to about 2.5 Gs of acceleration. By contrast, our reentry was completely silent and almost vibration free, except for the last ten minutes of buffeting as we slowed through the sound barrier nearing the runway.

On shuttle reentry, the forces put on the body as the craft decelerated through the atmosphere were only 1.7 Gs, and usually just a normal 1 G or so. But the peak deceleration lasted for about ten minutes, quite a strain to withstand after living in weightlessness for a couple of weeks. My heavy spacesuit felt like it was made of lead.

In the final minutes of reentry, the shuttle made an exhilarating spiral dive down to our landing site, followed by an eye-popping, nose-down plunge toward the runway. In the final seconds, our commander executed a last-second pullout to a gentle touchdown—it was a great moment to be alive!

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