When SpaceX successfully landed its first rocket booster without breaking it into a million pieces, the event took the world by surprise. As they launched more payloads into space, landing 1st boosters in one piece became a norm (unless they explicitly chose not to recover it due to geographical constraints).
While SpaceX’s more recent launches were becoming a text book exercise, the Iridium-4 mission on December 22nd was quite different due the time they launched. Rocket launch times are not random, as getting various payloads to their destination (whether it be a delivery to space stations or placing satellites into an orbital plane) requires laser precision. This is why some missions end up getting scrapped from the first sign of bad news (e.g. a small malfunction or bad weather).
The Iridium-4 payload, carrying its fourth batch of 10 Iridium-NEXT communication satellites, blasted off from the Vandenberg Air Force Base in California at 5:23 PM Pacific Time. As it was already just past sunset in California, most expected to see just the bright flames from the Falcon 9 booster as it headed into space.
Most did not expect an amazing light show as the plumes of smoke from exhausts were illuminated by the sun’s rays as it climbed high enough over the horizon. Even though it was already dark in California, the timing was just right where the sun was still visible at much higher altitudes (hence the regular occurrence of ISS and other satellite flares).
As the launch vehicle climbed into the path of the rays, the narrower exhaust plumes from the Falcon 9 1st stage booster became illuminated. Shortly after, it dissipated as the main engines cut off in while being separated from the 2nd stage. It should be noted that the dissipation is not seen in the video. When the trail disappears, it most likely was because of the cloud blocking that section of sunlight.
The 2nd stage then fired up its single Merlin engine (similar to the nine found in the main booster) and continued into space, but the engines from the 1st stage booster re-ignited as it then propelled itself sideways and away from the 2nd stage, hence the excess wash at the beginning of the 2nd stage’s ignition. Once it completed its burn, it then used nitrogen cold gas thrusters to help with orientation as it headed for a landing in the nearby ocean.
As the 1st stage completed its final burn and cleared away from the 2nd, the plume became smoother in appearance (as there was no more wash from the 1st stage). You can also see puffs of nitrogen as the 1st stage continued to orient itself to stay on target.
Shortly after, two white dots were seen splitting from the 2nd stage. These were the two protective fairings separating and falling back to Earth.
It was quite the sight to see, making it a perfect last launch for the year for SpaceX. I guess we can also say Iridium is lighting up the sky once again, as their first generation satellites have quite the reputation of producing bright flares due to the 3-sided placement of its main mission panels.
Here is some footage captured by the Bakersfield Now news team in Bakersfield.
Here’s an even brighter shot captured from the East San Gabriel Valley area.
Also, if you happen to be driving and see something as amazing as this, it’s always a good idea to pull over if you’re interested in looking on as being distracted can result in you slamming into someone else’s car (as proven in this video below).