This year marks 40 years since astronaut Bruce McCandless II conducted the first untethered spacewalk.
When I saw the story pop up with that iconic photo of him just floating in space 300 metres away from the space shuttle Challenger, it wasn’t the first time I had seen it, but it once again sparked that sense of awe of what a remarkable accomplishment it was.
Of course, he was not just floating, more like falling at an almost incomprehensible speed.
I was initially struck by the idea that this two-million-kilogram spaceship was travelling approximately 28,000 kilomtres per hour. Even with a jet-pack, how does the astronaut stay close enough to the shuttle to get back on board?
My first instinct was Google, but that just shows how conditioned I’ve become to having virtually all of humankind’s accumulated knowledge at my fingertips.
All I really had to do was remember my high school physics and Newton’s First Law of Motion, which states that an object in motion will remain in motion at the same speed and in the same direction unless acted upon by an unbalanced force.
That is the other conditioning piece of this. Here, within the Earth’s atmosphere, there are always unbalanced forces working on us. It’s our reference point.
We can dramatically see this by watching skydivers. At the instant parachutists step out of the airplane, they are travelling at the same speed in the same direction as the aircraft but are quickly separated from it. Without the thrust of the engines, the lift of the wings and the momentum of the much heavier plane, gravity, the drag of air molecules and the weight differential act upon their bodies causing them to fall toward the surface of the planet.
We all remember the instructions that went along with a lot of those high school physics word problems. “Assume this is happening in a vacuum.”
Near space, where the space shuttles operated, is not a perfect vacuum, but close enough. Once in space, the shuttles travelled on forward momentum with the much-weakened force of the Earth’s gravity slowly pulling them back in free fall. When McCandless let go of the Challenger with no other forces aside from gravity acting upon him, he maintained the speed and trajectory of the shuttle and they both just continued their slow fall back to Earth together.
With the help of a jet pack he was able to maneuver, thus allowing him to complete the untethered space walk and rejoin the rest of the crew inside.
Phew.
The word hero is one of the most overused in the English language, but being the first to do something like that is, indeed, heroic.
Trusting the physics, the technology and your own ability to perform when what is at stake is your own life, is almost unfathomable to me.
“It may have been one small step for Neil, but it’s a heck of a big leap for me,” McCandless said.
It has been said many times in many ways, but bravery isn’t being fearless, it’s being afraid but doing it anyway.
I am grateful to all the Bruce McCandlesses throughout history who have mastered their fear and advanced human knowledge with their big leaps.