I watched a rocket launch today! It had been a while since the last one, the
Space Shuttle, back in 2008. This rocket is much smaller, but still really cool. It launched from Vandenberg Air Force Base, on the sort of western middle area between San Francisco and Los Angeles. The coolest thing about this launch is the rocket bottom part (the booster) comes back and lands! So it launched in the middle of the morning, and there were tons of people watching. The actual start is behind a hill, but it popped up over the hill with a bright blazing pillar of fire underneath and everyone started cheering. I took some shots early, but the exposure was wrong. So by the time I got the camera set up correctly, it was up a ways, and the first shot (above, its going about 600 mph and about 10,000 ft, I think.
Then it passed through a layer of different air where it began to make a cloud behind it, and this was also around the time of max Q, which is when the air is pushing on it the hardest. As it goes faster there is more air pushing on it but as it goes higher there is less air. At some point it has a maximum of air it pushes against, and this is that point. After this, it becomes easier to push, until it gets into "no air at all" or what you might call... SPACE! The rocket is still going very vertical, and it was really cool to see the vapor cloud make a shadow through the air.
This shot is a little later on, when the rocket is much higher. If you compare this to the first shot, you will see the exhaust doesn't go straight down anymore, but puffs out a ways before going down. It looks rounded and wider. This is because the engines try to push the exhaust straight down, but they try to match the sideways pressure, sideways from the exhaust plume direction, and that pressure at sea level is higher, but at this height is much lower. So the plume can expand now but earlier could not. This means the engine isn't as efficient now. Which is one of the reasons to use stages: to stack a rocket on top of another rocket. The second stage has an engine that works better way high up.
This shot you probably have to click on it to see closely, but the stages have separated, and the booster is doing a return to launch pad burn. So the booster went up, then comes down, but since it also went sideways a bit (since the satellite wants to orbit the earth, which means going fast sideways), it has to cancel that sideways motion. I was expecting it to turn exactly 180 degrees and burn straight back. But it didn't do that! I was totally stunned, and it took me a while to figure it out. Here's what happened: The booster started due west of me, and headed southeast. When it shut off, it was about due south of me. The turn around burn pointed north, towards me. So if you start on the earth and go southeast and then north, do you arrive in the same location? The answer is yes, if you go up! Since the earth is turning, and rotating to the east (you are going east right now), if the rocket went straight up, it would end up west of the spot it started. So this rocket looked like it was going in a triangle, but the actual trajectory is more like a rounded curve (looking from the above view), and as it came down, the landing pad moved over to catch it. Luckily, the earth was moving fast enough to catch the rocket perfectly.
In this shot you can see the rocket is coming down at an angle. This is a way of steering, and making it so it doesn't have to burn as much fuel to still make it back to the landing pad. I think that's cool. Also its doing a re-entry burn, which is to slow it down just as it is coming back into the thicker atmosphere. Because it was falling, it got going really fast, and would burn up if it didn't slow down now. Sort of like jumping out of an airplane, falling really fast, but then popping a parachute so you don't hit the ground so fast. Except the rocket is still going really fast after this burn, so it did another burn at the end.
The landing burn! I didn't get to see the legs deploy, because it was behind the hill, but they come out next and it lands. Do you see the difference in color of the sky here vs the ones above? Its the same exposure, but there's just more air! Also, you can see the exhaust plume is very thin again, indicating lots of pressure around the rocket.
Then I went for a walk on the beach (that had been closed before for safety) and I saw the booster on the landing pad with a crane about to get it stowed away. Its amazing how big these things are.
On that same beach there were some Snowy Plovers! This one was very cute.
And I really like the succulent plants on the beaches here. These reminded me of a rocket launch with the fiery burning colors, like pillars of flame!
