THE ORBITER EJECTOR PROJECT (NASA and NCSU)

 

1. Purpose of the NCSU Orbiter Ejector Project: To design and fabricate a device launched from the cargo bay of the shuttle that ejects 6 spheres into precise orbits.
2. Joint Effort: NCSU Orbiter Ejector Project is part of a joint effort called the Orbital Debris Radar Calibration Spheres Project (ODERACS) headed by NASA Johnson Space Center (JSC) in Houston, TX. The key participants are JSC, NASA Goddard Space Flight Center (GSFC), and NCSU.
3. Principle Investigator of ODERACS Project: John F. Stanley (JSC).
4. Principle Investigator of NCSU Orbiter Ejector Project: Larry Silverberg (NCSU).
5. Purpose of ODERACS Project: To release spheres of known physical size and albedo into low Earth orbit in order to calibrate ground-based radars and optical telescopes with small objects.
6. Overall Goal: To provide a means for end-to-end radar and optical calibration necessary for precision measurements of small orbital debris.
7. Sequential ejection of calibrated spheres from shuttle.
8. Sphere 'package' to consist of 3 pairs of spheres, of 2, 4, and 6 in diameters.
9. Primary function: Calibration of Haystack and HAX radars and NASA data analysis facility in support of orbital debris measurements.
10. Sphere acquisition and tracking by other selected ground-based sensors:
    • Eglin radar
    • Kwajalein radars
    • Geodds telescope
    • SSB telescope
11. Other users: USAF, US Army, SDI, etc.
12. Chronology of NCSU Orbiter Ejector Project:
    • Fall &Spring semester 1991: 40 NCSU students divide into 4 teams, compete with each other and fabricate 4 competing prototype designs
    • Summer 1991: Flight systems of two of the four designs are fabricated (they're called the OEM-6 and OE-6 designs)
    • The 2 designs are fabricated by the following undergraduate students in the summer of 1991:

      Andy Mueller	Robert Long
      Peter Sramka	Joseph Cody
      Ayberk Abayhan	Robert Trask
      Mark Cassada	Michael Norton
      Paul Shumacher

    • NASA selects the OE-6 design
    • Orbiter Ejector is delivered to NASA in November 1991
13. OE-6 undergoes NASA certification:
    Vibration testing - February 1992
    Thermal Vacuum Testing - April 1992
    EMI (Electromagnetic Interference) Testing - June 1992
    
14. Delivery to Kennedy Space Center (KSC) in July 1992.
15. Orbiter Ejector is flown in December, 1992 aboard Shuttle flight STS-47. Experiment fails due to dead battery.
16. Orbiter Ejector is reflown successfully on shuttle flight STS-53 in December 1993.
17. Orbiter Ejector is flown successfully again on shuttle flight STS-60 in August 1994.
18. Sphere Ejection Parameters:

Sphere Ejection Parameters

Ejection Order	Diameter (inches)	Mass	Exit Velocity (m/s)	Composition
1	4.000	4.256	2.85	440 SS
2	4.000	4.256	2.45	440 SS
3	2.000	0.532	2.13	440 SS
4	2.000	0.532	1.85	440 SS
5	6.000	5.000	1.61	6061-T6 AL
6	6.000	5.000	1.40	6061-T6 AL