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Maui Optical Tracking & Identification Facility (MOTIF) (U)

Overview (U):

(U) The Maui Optical Tracking & Identification Facility (MOTIF) is co-located with AMOS and GEODSS and jointly shares the Maui Space Surveillance Site (MSSS). MOTIF is a primary sensor of the USAF SPACETRACK network operated by Headquarters Air Force Space Command (HQ AFSPC).

(U) The system consists of two twin telescopes on a single mount. The telescopes work in both the infrared and visible spectrums. This allows the system to track near earth objects. The dual 1.2-meter telescopes (Figure 3-1) are mounted on opposite sides of a single polar axis and are fixed to a common declination axis. Both of these major telescopes are open-tube, classical Cassegrain optical systems having parabolic primary mirrors and hyperbolic secondaries. Both have Invar metering rods installed between the primary and secondary mirrors to minimize thermally induced changes.

Description (U):

(U) MOTIF has a telescope with a 29 inch back focal distance and is thus known as the B29. This telescope has a single Blanchard instrument mounting surface (named for the Blanchard surface grinder), at the rear of the telescope, with an 11 inch instrument working distance (distance beyond the Blanchard mounting surface to the focal plane). All the Blanchard surfaces are centrally perforated to allow the light to pass through to the focal plane. The B29 has a relative aperture of f/20, a focal length of 24.56 meters (967 inches), and a plate scale of 8.4 arc seconds/mm. It is used primarily for Long Wave InfraRed (LWIR) and photometric data collection. The B29 telescope is located on what would normally be the counterweight side of a standard equatorial mount. It is equipped with a toggling secondary mirror that is used with the Contrast Mode Photometer (CMP) and the infrared radiometer known as AMTA. Its optical performance in the visible is two times the diffraction limit.

(U) The other 1.2-meter telescope has a 37-inch back focal distance and thus is known as the B37. The B37 has a relative aperture of f/16, a focal length of 19.81 meters (780 inches) and a plate scale of 10.4 arc seconds/mm at the Cassegrain focus. This telescope has two Blanchard-ground instrument mounting surfaces, one at the side, and one at the rear. Both have 19-inch instrument working distances. A 45o folding mirror between the primary and secondary mirrors directs the telescope beam to the side or lets it pass through the rear Blanchard surface. The position can be switched in a few seconds. The B37 telescope is normally used for low-light metric tracking using the Low Light Level TV camera (LLLTV), located within the MOTIF Advanced Imaging System (MAIS) sharing the rear Blanchard with the MAIS imaging camera. In the past, a "seeing" monitor has occupied the side Blanchard and can be restored if required. In the visible wavelengths, the B37 optical performance is three to four times the diffraction limit.

(U) Each 1.2-meter telescope has a primary mirror support system that incorporates three air bags for axial support and a mercury belt for radial support. Simultaneous boresighting of the two optical systems is accomplished by means of a beam steering system that drives the B37 secondary (strabismus or "wall-eyed" correction). The B37 secondary is tilted to "bend" the optical axis of the B37 to maintain parallelism with the B29 telescope. Data for the strabismus correction is contained in the computer Mount Model (MM) and is calibrated using stellar observations.

(U) Mounted along side of the B29 telescope is the dual-aperture MOTIF Acquisition Telescope System (MATS), with three switch-selectable fields of view and projection reticles.

User Impact (U):

(U) Loss of this site would significantly reduce satellite imaging, tracking and IR Signature characterization.

Programmatics (U):

(U) Operational.

(U) Organizations and Funding:
  • (U) AFSPC: Funding Source.

Images (U):

MOTIFMOTIF Telescope Layout
This Table Is Unclassified.

Related Initiatives (U):
AMOSAir Force Maui Optical Station (AMOS)
MSSSMaui Space Surveillance System (MSSS)
This Table Is Unclassified.

Related Requirements (U):None.

Related Categories (U):
Dedicated SensorsDedicated Sensors
This Table Is Unclassified.

Road Map Placements (U):

This Table Is Unclassified.

Requirements, Funding and Additional Hotlinks (U):

1997 Space Surveillance Dev Plan
This Table Is Unclassified.

Lead Office (U):

(U) Air Force.

Point of Contact (U):

(U) Maj Mike LaPointe, NSSA, Open Phone: (703) 325-6422, DSN 221-6422.
(U) National Security Space Road Map Team, NSSA, Open Phone: (703)808-6040, DSN 898-6040.

Date Of Information (U):

(U) 17 September 1998

(U) Road Map Production Date: 12 July 1999

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