What you’re looking at is a cavalcade and culmination of hundreds of things all going right, with no room for error. It’s slowed down a bit so you can take it in a little easier and enjoy the view and the sound. By the way, the sound I added in because their high-speed cameras don’t have mics. Also, a mic in such close proximity to the stack at liftoff would be virtually useless as the acoustic shockwaves are enough to kill a human being. So, I took existing launch sounds and manipulated them to fit what you see.
So, what in the world is going on here? Well, there is an excellent write up on this topic. I am going to post it here because I don’t think reinventing the wheel is necessary. Read the excellent work (with video clips!) here.
In short, a LOT of things happen in the last 10 seconds before liftoff. To massively over-simplify the process:
- The command is sent to ignite the engines.
- They are started in a staggered sequence to ease the stress on the system.
- The hydraulics are temporarily disengaged so that the shock of starting the engines does not break the mounts they are on.
- The engines noticeable wobble as they are fired and once fully running, stabilize. This is when we see the Mach diamonds form.
- Hydraulics are re-engaged and the engines swivel into position for liftoff.
- At T-0 the computer checks that all are running and healthy. If so…
- The hold-down bolts are blown along with igniting the solid rockets.
- Liftoff!
This all happens in 6.6 seconds.
From nothing to running at 104% of rated thrust to flying; in 6.6 seconds. Not many machines can do that. Space Shuttle could. You could literally write an entire dissertation on just the main engines and how they work. That is how complex they are.
She was flawed, yes, but she was my generation’s spaceship. I hope future generations can remember the triumphs as well as the tragedies.
Ad astra per aspera – loosely translated, it means “To the stars with difficulty”. It just means it’s hard to do and will likely always be hard to do. Hence, my respect for the people that do it.