Flight Recap of EOSS-18

note: This synopsis has been reconstructed using telemetry logs and my personal memory. Uh, oh. Any errors are mine and if discovered will be corrected.

Launch Date: August 27, 1994
Launch time: 16:26 UTC
Launch site: Monument, Colorado

Launch site Coordinates:   Latitude    39 deg 02.67'N
                                    Longitude  104 deg 52.53'W

Burst Time: 17:36 UTC
Balloon Burst Altitude: 93,000 feet

Balloon Burst Coordinates: Latitude    39 deg 04.80'N
                                    Longitude  104 deg 46.26'W

Touchdown Time: 18:13 UTC
Landing Site Coordinates:  Latitude    39 deg 06.46'N
                                    Longitude  104 deg 40.35'W

Ascent Rate:                490 fpm
Descent Rate:              2400 fpm (avg.)

Payload Frequencies:
Telemetry: 144.340 MHz
ATV: 426.250 MHz
Beacon: 147.555 MHz

The purpose of Flight 18 was to test the effectiveness of a spin stabilization system developed by Larry Cerney, N0STZ. The system consists of a gyroscopic sensor to determine spin directions and rates and an airfoil used to add counter torque against these induced spins using the air currents developed by the balloon ascending through the air at speeds of around 5 to 10 miles per hour.

At low altitudes where the surrounding air is dense, it appears that this experiment works. Spin is detected and the payload quickly brakes it's rotation to present a stable picture. However, the system reacts a bit slowly and so we still get quite a bit of initial spin. As the payload ascends into higher and less dense atmosphere the system's effectiveness becomes reduced.

A secondary payload from NAVSYS, a TIGET, was flown. A TIGET is a GPS sonde. Essentially a throwaway gps receiver that is very low in cost because it carries no onboard processing power. GPS determination is done by capturing the gps signals at the TIGET's location and relaying them to the ground. A ground based system processes the data from those signals and computes the position of the TIGET.

It's a good thing TIGETs are disposable. This one became separated from the main payload and was lost.

Recovery of the rest of the payload was accomplished quickly by the Tracking and Recovery Team.


Photos and Charts

I did some charting of the data returned by the shuttle for this flight. Those charts and a picture are AVAILABLE HERE.