I went to see the Delta IV-Heavy rocket launch at Vandenberg Air Force Base in Lompoc, California on January 20. With the capacity to lift 23 tons of payload to low-Earth orbit, the rocket was the biggest to launch from the west coast of the United States to date, and it was a spectacular show.

The launch was delayed by two-and-a-half minutes from the initial schedule to avoid a piece of space debris, but otherwise it appeared to go flawlessly. As it was launching a National Reconnaissance Office payload, very little is public about the mission itself, including its destined orbit or how many satellites it was deploying. All we know is that they needed the ability to launch 23 tons to orbit.

The rocket lifted off from Vandenberg AFB’s Space Launch Complex 6 (SLC-6), a launch pad built for high-profile missions. But SLC-6's place in history has been undercut many times due to various changes in the US space program.

A long road to launches

The construction of SLC-6 was first started in 1966 to serve the Manned Orbital Laboratory (MOL) program. MOL’s mission was to launch astronauts to space to conduct experiments and reconnaissance activities, and it used a Gemini capsule modified to be launched with a space laboratory. The program had been developed to follow a canceled military space project, Dynasoar, but, in 1969, MOL was cancelled as well. The construction of SLC-6 was frozen even though the launch pad was almost completed.

Next came the Space Shuttle in the 1980s. SLC-6 was to be the main launch site for the Shuttle’s polar-orbit missions, and the launch complex was refurbished for Shuttle launches and declared operational on October 15, 1985—Discovery was to become the first Shuttle launch from Vandenberg on October 15, 1986. However, the Challenger disaster earlier that year changed everything, and SLC-6 never received a Shuttle to launch—all it got was the shuttle Enterprise for ground tests. Enterprise is of course the Shuttle airframe developed for atmospheric testing, and was not made to go into orbit. After the change in the Shuttle program, SLC-6 stayed dormant for yet another decade.

The first launch from SLC-6 took place on August 15, 1995, almost 30 years after it was built, when an Athena 1 rocket boosted off the pad. However, the rocket lost control shortly after launch and was destroyed in a controlled explosion when it deviated off course. The first successful launch finally took place in August of 1997.

Getting heavy

SLC-6 has been in its current configuration since 2003, which enables it to launch the Delta-IV series of rockets. Two successful Delta IV-Medium launches took place in 2006, and the pad went through another extensive renovation so that it can launch the Delta IV-Heavies.

Yesterday’s launch, at 1:10pm PST, was the first Delta IV-Heavy from the refitted SLC-6. The expendable booster is powered by three RS-68 engines that burn liquid hydrogen and oxygen. Each RS-68 provides 660,000 pounds (about 3 MN) of thrust. The rocket configuration yesterday used no solid rocket booster, so it produced very little smoke. The rocket’s trail consisted only of water vapor—pure bright white against the cloudless blue sky of a perfectly sunny Californian January day. You can see it in the photo above: three distinct rocket engine flashes atop a towering cloud of water vapor. I happened to be positioned such that I ended up in the shadow cast by the vapor trail, so the rim of the trail is brightly outlined by the scattered sunlight shining from behind.

This was my fifth trip to Vandenberg to see a rocket launch; the first two got scrubbed and I had to go home empty-handed. The third time, it launched an Atlas V, except that it launched into a heavy fog with 100ft visibility, and I was standing 3 miles away from the pad. I felt the ground rumble, and heard the rocket engines roar, but saw absolutely nothing. Fourth time was a Minotaur IV last October—it was a solid-rocket booster, which creates an extremely bright engine flame. The launch took place after dark, and created a spectacular show that lit up the entire night sky.

And then the Delta IV-Heavy yesterday my experience just keeps getting better, and I am convinced that the best way to experience a launch is just to be there. The dynamic range of everything you see, hear, and feel is so large that no recording device can capture the entire range of sensation. The 75 meter tall rocket is surely a huge piece of hardware, but it climbs on top of a vapor trail that at the end is tens of miles tall, and you can see the rocket engine flames for quite a long time. It is hard to appreciate the scale unless you are there standing on the rumbling ground. The low-frequency bass sound is unlike anything I’ve ever heard, and I felt it with my skin too.

These big launches just don’t happen very often, and I highly recommend the experience. The next Delta IV-Heavy launch will take place in Cape Canaveral this December. And then there are two more Shuttle launches before the Shuttle program comes to its end; a Shuttle launch is of course way bigger than the Delta-IVs. Get this: each of the Space Shuttle main engines produces 490,850 pounds (2.18MN), and then one solid rocket booster does whopping 2,800,000 pounds (12.5 MN)—a Shuttle uses three main engines and two boosters! The next Shuttle Launch is currently scheduled for February 24, in Florida.

I will be thinking about all the missed opportunities SLC-6 has had when it goes up.