MODIS Components

The MODIS instrument has been designed and developed since the Engineering Model (EM) was completed in mid-1995. Since then, two spaceflight units, the Protoflight Model (PFM) (aboard the Terra Satellite) , and the Flight Model 1 (FM1) (aboard the Aqua Satellite) have been completed and launched. Terra was launched on December 18, 1999, and Aqua was launched on May 4, 2002. The MODIS instruments — built to NASA specifications by Santa Barbara Remote Sensing — represent the finest in engineering of spaceflight hardware for remote sensing.

The MODIS instruments were designed with the following subsystems and abilities. Follow the highlighted links for more technical descriptions of each subsystem.

•Atmospheric, land, and ocean imaging in a single instrument

•1,000-m, 500-m, and 250-m resolution spectral bands

•Custom-tailored spectral bands from 0.4 to 14.4 µm; low out-of-band response

Opto-Mechanical System


•Continuously rotating double-sided Scan Mirror Assembly for long life

Passive Radiative Cooler

•Advanced Focal Plane Assembly (FPA) technology for unsurpassed sensitivity

Optical Bench Assembly

Optical System Description

•Door Assemblies

    •Earth-Viewing Door

    •Solar-Viewing Door

    •Space-Viewing Door

Electronics System

Space-Viewing Analog Module

Forward-Viewing Analog Module

Main Electronics Module (MEM)

On-Board Calibration System

•IR calibration every scan for low 1/f noise and high accuracy

•Low ghosting, low scatter optics

•On-board Solar Diffuser and Solar Diffuser Stability Monitor (SDSM)

•On-board full-aperture Blackbody (BB)

•On-board Spectroradiometric Calibration Assembly (SRCA)