Iridium Launch Math Question

Brian Webb (
Fri, 14 Nov 1997 00:01:38 -0500

Last Saturday night I was on a high mountain southeast of Vandenberg Air Force
Base and observed the awesome dusk launch of the Delta II booster carrying five
Iridium satellites.

I was taking 35mm color still photos and managed to capture the missile and its
huge exhaust plume as it headed down range. One photo (frame 29A) was taken at
1/30th of a second and imaged the missile, plume, and Venus. I know the exact
field of view of the print along with some other info.

Here are my questions regarding frame 29A:

1. What is the latitude and longitude directly under the missile?

2. How high was the missile (in km) above the Earth?

3. What are the dimensions (in km) of the exhaust plume?

Here's the background information:

1. Missile Trajectory: The missile was launched from pad 2-West at 34 deg 45 min
04 sec north/120 deg 37 min 32 sec west and flew down range on an azimuth of
200.0 deg from true north.

2. Photo Site: The photo was taken from Santa Ynez Peak at 34deg 31min 30sec
north/119 deg 57 min 30 sec west. The elevation was 4,200 feet above sea level.

3. Photo Info: In the photo, the missile has an azimuth of 196.36 deg from true
north and an elevation above the horizon of 10.72 deg.

The exhaust plume center has an azimuth of 197.65 deg from true north with an
elevation of 11.87 deg above the horizon. The length of the plume was 5.24 deg
and the width was 1.53 deg.

I'd really appreciate it if those of you who are math enthusiasts could help me
with this.


Brian Webb
Thousand Oaks, California