The 400 Gb LRO mass memory is implemented in synchronous DRAM that is interfaced to the RAD750 computer via the PCI bus on a custom C&DH backplane.įigure 4: Block diagram of the C&DH subsystem and interfaces (image credit: NASA, BAE Systems)
The LROC instrument is connected directly to one of the processor board’s SpaceWire links, while the Mini-RF connects to the Housekeeping and Input/Output (HK/IO) board that also implements a SpaceWire router using an Actel FPGA and is then routed to the processor board across the SpaceWire bus via the FPGA that implements another SpaceWire router. Both the Ka-band and S-band communications boards include SpaceWire interfaces with routers, implemented in Actel FPGAs. The SpaceWire router is implemented in the SpaceWire ASIC that is in turn connected to the RAD750 microprocessor via the PCI bus and the second generation enhanced Power PCI bridge ASIC. Within the C&DH unit, the RAD750 flight computer communicates with the instruments and other boards via three interfaces: a four-port SpaceWire router, a 32 bit, 33 MHz PCI bus, and a redundant MIL-STD-1553 bus. The Mini-RF instrument is connected to the SpaceWire network through the SpaceWire ASIC. The spacecraft payload includes seven instruments, two of which are connected to the Command and Data Handling (C&DH) unit developed by NASA Goddard Space Flight Center via the SpaceWire network, as shown in Figure 4. 6) 7)įigure 3: Block diagram of the LRO spacecraft (image credit: NASA/GSFC) Attitude and momentum control functions are performed in ACS control modes that process sensor data and generate appropriate actuator commands. Part of the ACS FSW function is to provide commands to the SA (Solar Array) and the HGA (High Gain Antenna).
#Who sees lunar reconnaissance orbiter photos first software
This software also includes some FDC (Failure Detection and Correction) algorithms used in safing. The ACS hardware is controlled by ACS flight software (FSW) resident on the SBC (Single Board Computer). The 2 A-STR, built by SELEX Galileo, provide a spacecraft attitude quaternion in the J2000 ECI (Earth Centered Inertial) reference frame. Once in observing mode, the reaction wheels keep the boresight of the instruments pointing continuously at the surface of the moon. The reaction wheels are specifically designed to provide very quiet, smooth changes in pointing of the spacecraft. MIMU provides attitude rate information up to 18 º/s and attitude rate polarity from 18º/s up to 60 rpm. The ACS (Attitude Control Subsystem) consists of the following components: 10 CSS (Coarse Sun Sensors), 4 RW (Reaction Wheels), 2 A-STR (Autonomous Star Trackers), and a RLG (Ring Laser Gyroscope) of Honeywell, referred to as MIMU (Miniature Inertial Measurement Unit). LRO is a 3-axis stabilized, nadir pointed spacecraft designed to operate continuously during the primary mission. The spacecraft architecture emphasizes modularity through the use of standard interfaces. The spacecraft is being built and integrated at NASA/GSFC (inhouse development), Greenbelt, MD. 2006.įigure 1: Artist's view of LRO spacecraft (image credit: NASA) Spacecraft The CDR (Critical Design Review) of LRO was completed in Nov. The orbiter project is managed by NASA/GSFC while NASA/ARC manages the LRO payload. Provide measurements to characterize future robotic explorers, human lunar landing sites and to derive measurements that can be used directly in support of future Lunar Human Exploration Systems.Study the moons polar regions for resources that could be used in future manned missions or robotic sample return missions.Collect data on the moon's radiation levels.Gather detailed maps of the lunar surface.
The objectives of LRO are to: 1) 2) 3) 4) 5) The LRO requirements call for a mission life of one year in lunar orbit. LRO is the first mission of NASA's `New Vision for Space Exploration', which President Bush announced on January 14, 2004, in sending more robot and human explorers beyond Earth orbit. LRO is a NASA mission to the moon within the Lunar Precursor and Robotic Program (LPRP) in preparation for future manned missions to the moon and beyond (Mars). LRO (Lunar Reconnaissance Orbiter) + LCROSS
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