The Integrated Apogee Boost Stage (IABS - alternately, Integrated Apogee Boost Subsystem) was an American rocket stage used for the launch of Defense Satellite Communications System III satellites to geostationary orbit when using a launch vehicle without an upper stage capable of delivering them there directly.[1] Earlier DSCS III satellites had launched on the Titan 34D (using the Transtage or Inertial Upper Stage) and Space Shuttle Atlantis (using the Inertial Upper Stage), which were capable of delivering them directly to geostationary orbit - as such, the satellites were not capable of moving from geostationary transfer orbit to geostationary orbit themselves. Because of this, launch of these satellites on the Atlas II and Delta IV families required an apogee kick stage - the IABS - to be added to the satellite. The IABS was developed by GE Astro Space, who also manufactured the DSCS III satellites it was designed for.[2][better source needed]
 Illustration of IABS carrying its payload, a DSCS III satellite, to geostationary orbit. | |
| Manufacturer | GE Astro Space |
|---|---|
| Country of origin | United States |
| Used on | Atlas II, Atlas IIA, Delta IV Medium |
| General characteristics | |
| Height | 0.68 m |
| Diameter | 2.9 m |
| Gross mass | 1578 kg |
| Propellant mass | 1303 kg |
| Empty mass | 275 kg |
| Launch history | |
| Status | Retired |
| Total launches | 10 |
| Successes (stage only) | 9 |
| Failed | 1 (payload reached final orbit on its own) |
| First flight | Feb 11, 1992 |
| Last flight | Aug 29, 2003 |
| Integrated Apogee Boost Stage | |
| Powered by | 2 R-4D |
| Maximum thrust | 980 N |
| Specific impulse | 312 s |
| Propellant | NTO/MMH |
Design
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IABS consisted of a flat, disc-shaped stage powered by two pressure-fed R-4D rocket engines, fed from a ring of spherical composite overwrapped pressure vessels containing nitrogen tetroxide and monomethylhydrazine propellants.[3] The stage was spin-stabilized, rotating at 20 rpm.[4] An onboard solar array around its ring-shaped exterior, separate from that of its payload satellite, allowed IABS to remain operational for up to 12 days,[5] granting flexibility in mission planning. IABS was originally intended to make two burns while delivering DSCS III satellites - however, fuel feed problems after the first burn of its first mission rendered the second burn impossible, requiring the payload to maneuver to its final orbit on its own using its reaction control system. On later flights, these two burns were combined, avoiding this problem.[6]
Flights
edit| IABS Designation | Date | Payload | Launch Vehicle | Launch Site | Outcome |
|---|---|---|---|---|---|
| IABS-01 | Feb 11, 1992 | DSCS III B14 | Atlas II | LC 36A | Partial Failure |
| IABS-02 | Jul 2, 1992 | DSCS III B12 | Atlas II | LC 36A | Success |
| IABS-03 | Jul 19, 1993 | DSCS III B9 | Atlas II | LC 36A | Success |
| IABS-04 | Nov 28, 1993 | DSCS III B10 | Atlas II | LC 36A | Success |
| IABS-05 | Jul 31, 1995 | DSCS III B7 | Atlas IIA | LC 36A | Success |
| IABS-06 | Oct 25, 1997 | DSCS III B13 | Atlas IIA | LC 36A | Success |
| IABS-09 | Jan 21, 2000 | DSCS III B8 | Atlas IIA | LC 36A | Success |
| IABS-08 | Oct 20, 2000 | DSCS III B11 | Atlas IIA | LC 36A | Success |
| IABS-10 | Mar 11, 2003 | DSCS III A3 | Delta IV Medium | LC 37B | Success |
| IABS-07 | Aug 29, 2003 | DSCS III B6 | Delta IV Medium | LC 37B | Success |
See also
editReferences
edit- ^ "IABS". space.skyrocket.de. Retrieved 2021-12-13.
- ^ "Bo Lewis".
- ^ Beeson, Harold D.; Davis, Dennis D.; Ross, William L.; Tapphorn, Ralph M. (2002-01-01). "Composite Overwrapped Pressure Vessels: Database Extension Task 3.0 and Impact Damage Effects Control Task 8.0". NASA Sti/Recon Technical Report N. 03. NASA: 14821. Bibcode:2002STIN...0314821B.
- ^ "DSCS IABS". milsatcom.tripod.com. Retrieved 2021-12-13.
- ^ Magazines, Hearst (August 1992). Popular Mechanics. Hearst Magazines.
- ^ "The Cape, Chapter 3, Section 8, ATLAS II/CENTAUR Missions". spp.fas.org. Retrieved 2021-12-13.