Space and astronomy news and information for the American Southwest. Coverage includes Vandenberg AFB rocket and missile launches.

Delta II Launch Visibility

by Brian Webb

2014 June 27

Next Tuesday’s early morning launch of a Delta II rocket from Vandenberg AFB remains on schedule. The Delta is slated to lift off from Space Launch Complex 2 West on July 1 at 02:56:44 PDT (09:56:44 UTC), the start of a 30-second launch window. Following liftoff, the rocket will rise vertically for several seconds, and then slowly pitch over and head southward. Several minutes later, the Delta should place NASA’s Orbiting Carbon Observatory-2 satellite into a polar orbit.

Since the launch occurs on a moonless night, the event could be visible to the naked eye for hundreds of miles - perhaps as far away as portions of Nevada, Arizona, and Mexico.

Just before liftoff, the Delta's first stage liquid propellant main engine and three strap-on solid fuel rocket motors will ignite. Observers in outlying areas (15 to 75 miles away) may see a flash on the horizon from the direction of the pad, a few seconds of darkness, and then a rising orange orb or "star". The brightness and color of the Delta at this point will be largely due to the solid fuel motors' brilliant orange flame.

At T+ 1 minute 4 seconds, the solid rocket motors will burnout and the first stage will be powered solely by its liquid propellant main engine. Since the liquid propellant engine produce a dimmer, colorless flame compared to the solid rocket motors, the Delta will drop in brightness and resemble a moving white star.

Late into the first stage burn, observers in dark locations may see a tenuous, elongated or jellyfish-like, exhaust plume from the main engine. At T+ 4 minutes 24 seconds, the first stage main engine will cut off and the vehicle will disappear.

Several seconds later, the second stage will ignite and the rocket will continue its gradual climb into orbit. For most naked eye observers, however, the second stage burn will probably be invisible.

The visibility of the launch will depend almost entirely on the weather. During the warmer months of the year, the weather in central and southern California is fairly predictable. During the pre-dawn hours, the coast and areas several miles inland are usually plagued by fog or a layer of low clouds that extend up to about 1,500 to 2,000 feet (457 to 610 M) above sea level. However, at the same time, California’s interior tends to be clear.

Although the naked eye is adequate for viewing the launch, optical assistance will provide a better view. Binocular are good, but tripod-mounted binoculars are even better. An astronomical telescope will give the best view and may provide a dynamic, surreal light show.

To view the launch, find a location that is as high as possible, has an unobstructed horizon, and is far from city lights. Perhaps the best place to watch would be a spot in the coastal mountains or hills parallel to the rocket's flight path and high enough to be above any coastal low clouds.

If you plan to drive to the mountains for the launch, allow yourself plenty of time to get there and drive very carefully. Mountain roads are dangerous and careless driving or parking can lead to tragedy. Also, be aware of your surroundings after you get out of your vehicle. I once had a small rattlesnake slither by me as I waited on top of a mountain to view a launch.

For further information about viewing Vandenberg AFB rocket and missile launches, go to the following Web page:

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