NOAA KLM User's Guide

Section 1.2.1

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Introduction Page, NOAA KLM TOC, Acronyms
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1.2.1 Spacecraft Structure

The NOAA KLM spacecraft structure, based on the NOAA-H, I, J integrated structure, is designed to support a complete meteorological payload plus the necessary support subsystems to meet all interface and system requirements. The structure comprises four major assemblies: the Instrument Mounting Platform (IMP), the Equipment Support Module (ESM), the Reaction Control Equipment (RCE), Reaction Support Structure (RSS), and the Solar Array (SA) assembly. Figure 1.2.1-1 provides a line drawing of the NOAA KLM spacecraft and Table 1.2.1-1 summarizes the primary physical characteristics.

Figure 1.2.1-1 NOAA KLM Spacecraft Configuration.

Table 1.2.1-1. NOAA KLM Physical Characteristics.
Parameter NOAA KLM Characteristics
General
Configuration 3-axis body stabilized
Mission 2-years
Launch Vehicle Titan II
Spacecraft Size
Launch Configuration Envelope Expendable Launch Vehicle Static Envelope 2540 mm (100 in)
Fairing Diameter 3048 mm (120 in)
On-Orbit Configuration
Main Body Length 4.2 m (13.75 ft)
Main Body Diameter 1.88 m (6.2 ft)
Array to Body 3.2 m (10.5 ft)
Overall Length 7.4 m (24.2 ft)
Spacecraft Mass (Titan II)
Dry Satellite 1478.9 kg (3260.3 lb)
Propellant and pressurant 752.8 kg (1659.7 lb)
Total Deployment Weight 2231.7 kg (4920 lb)

1.2.1.1 Instrument Mounting Platform

The HIRS and AVHRR instruments are mounted on the Instrument Mounting Platform (IMP) because of stringent pointing requirements and/or the need for an uninterrupted view of space for detector-cooling purposes. The IMP also supports the primary attitude-sensing equipment: namely, an Earth horizon sensor, an inertial measurement unit and a Sun sensor. Overall, the approach achieves an instrument optical-axis pointing accuracy of better than 0.2 degrees relative to the local vertical. The surface of the IMP is the primary thermal control surface for the instruments. It houses an array of thermal control louvers, protected from solar illumination in mission orbit by a sunshade.

1.2.1.2 Equipment Support Module

The ESM contains the majority of the satellite electronic support equipment. It is pentagonal in cross section but asymmetric to provide a large Earth-viewing face upon which lower pointing accuracy instruments and antennas are mounted. Internal of the ESM are mounted most of the components contained in the data handling, attitude determination and control, communications, and command and control subsystems, as well as the SARR, SARP, and DCS instruments. External to the ESM, on the Earth facing surface, are mounted the AMSU-A1, AMSU-A2, AMSU-B, SBUV, as well as the communication system antennas. One segment of the mounting area, at the lower end of the module, is primarily dedicated to SAR equipment. Thermal control of the ESM itself is provided by thermal blankets and pinwheel louver assemblies integral to the side panels.

1.2.1.3 Reaction Control Equipment Support Structure

The RSS is a circular cylinder, which primarily supports a solid rocket AKM plus the Reaction Control Equipment (RCE) components consisting of two nitrogen tanks, two hydrazine tanks, four hydrazine thrusters, and eight nitrogen thrusters along with the valves and manifolding required to interconnect the system. In addition to the propulsion equipment, the RSS supports the satellite batteries, battery charge controllers (for thermal reasons these items are outside the ESM) and certain antennas. It also furnishes support for the solar array assembly. Table 1.2.1.3-1 lists the satellite equipment furnished by the government.

Table 1.2.1.3-1. Government-furnished Satellite Equipment List.
Item NOAA-K NOAA-L NOAA-M
AVHRR/3 X X X
HIRS/3 X X X
DCS/2 X X X
SEM/2 X X X
SARP/2 X X X
SARR X X X
SBUV/2   X  
AMSU-A1 X X X
AMSU-A2 X X X
AMSU-B X X X

1.2.1.4 Solar Array

The SA consists of 10 reinforced honeycomb panels, which are hinged to each other along their long edges. When deployed, the array is approximately 6.15 m (242 in) long by 2.73 m (107.5 in) wide. During launch, solar array panels are stowed on the ESM back apex panels. During mission mode, the array is supported from the RSS through the long boom, the solar array drive, the short boom and the mast. The array is canted 22 or 36 degrees from the short boom via the cant-deployment mechanism, located between the short boom and the mast.

1.2.1.5 Spacecraft/Launch Vehicle Interface

The NOAA KLM spacecraft will use modified, standardized Titan II launch vehicles. A two-piece conical ring (the payload adapter), furnished by the spacecraft contractor, provides the mechanical interface between the spacecraft and the launch vehicle.


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