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Integrated Apogee Boost Stage

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Integrated Apogee Boost Stage
Illustration of IABS carrying its payload, a DSCS III satellite, to geostationary orbit.
ManufacturerGE Astro Space
Country of originUnited States
Used onAtlas II, Atlas IIA, Delta IV Medium
General characteristics
Height0.68 m
Diameter2.9 m
Gross mass1578 kg
Propellant mass1303 kg
Empty mass275 kg
Launch history
StatusRetired
Total launches10
Successes
(stage only)
9
Failed1 (payload reached final orbit on its own)
First flightFeb 11, 1992
Last flightAug 29, 2003
Integrated Apogee Boost Stage
Powered by2 R-4D
Maximum thrust980 N
Specific impulse312 s
PropellantNTO/MMH

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]

Design

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A DSCS III satellite is integrated onto the IABS, between the fairing halves of its Atlas II launch vehicle

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

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Flights of the Integrated Apogee Boost Stage
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

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References

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  1. ^ "IABS". space.skyrocket.de. Retrieved 2021-12-13.
  2. ^ "Bo Lewis".
  3. ^ 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.
  4. ^ "DSCS IABS". milsatcom.tripod.com. Retrieved 2021-12-13.
  5. ^ Magazines, Hearst (August 1992). Popular Mechanics. Hearst Magazines.
  6. ^ "The Cape, Chapter 3, Section 8, ATLAS II/CENTAUR Missions". spp.fas.org. Retrieved 2021-12-13.