ASTER

ASTER
Name	ASTER
Mission type	Earth observation
Operator	Japan, NASA
Manufacturer	MITI, Mitsubishi Electric, Boeing
Launch date	1999-12-18
Launch vehicle	H-IIA
Launch site	Tanegashima Space Center
Orbit	Sun-synchronous

ASTER

ASTER is a high-resolution multispectral imaging instrument flown on an Earth-observing platform. It was developed through a collaboration among JAXA, NASA, and industrial partners to map land surface properties, monitor volcanism, and support geologic, cryospheric, and environmental studies. The instrument provided global coverage spanning visible, near-infrared, shortwave-infrared, and thermal infrared bands, enabling cross-disciplinary investigations by researchers affiliated with USGS, Caltech, University of Tokyo, Brown University, and international institutions.

Overview

ASTER operated as a pushbroom and whiskbroom sensor suite designed to collect multispectral data across multiple swaths. The project integrated expertise from JAXA, NASA Goddard Space Flight Center, Jet Propulsion Laboratory, MIT, Rutgers University, and industrial firms including NEC and Toshiba. The mission objectives aligned with programs such as Landsat Program, Earth Observing System initiatives, and cooperative research with agencies like European Space Agency and NOAA. ASTER datasets complemented archives from SPOT, IKONOS, QuickBird, Sentinel-2, and MODIS instruments.

History and Development

The concept for ASTER emerged through bilateral discussions between NASDA and NASA during the 1980s and 1990s, building on heritage from missions including Landsat 1, Landsat 7, and Terra. Development involved contracts awarded to Mitsubishi Electric and design reviews with teams from Caltech and University of Arizona. Major milestones included payload integration at Sagami Bay facilities, environmental testing at Ames Research Center, and delivery for the launch aboard an H-IIA vehicle from Tanegashima Space Center. Programmatic reviews referenced standards used by National Research Council reports and recommendations from Committee on Earth Studies panels.

Design and Technical Specifications

ASTER comprised three subsystems: the Visible and Near-Infrared (VNIR), Shortwave Infrared (SWIR), and Thermal Infrared (TIR) modules. VNIR used charge-coupled devices similar to instruments developed by Kodak partners, while SWIR detectors leveraged semiconductor technologies advanced at Riken and NTT. TIR sensors used cryogenic radiometry techniques informed by fielded designs from NOAA sounders and AIRS. The instrument delivered spatial resolutions of approximately 15 m (VNIR), 30 m (SWIR), and 90 m (TIR), with spectral coverage across 14 bands. Orbit parameters placed the spacecraft into a sun-synchronous orbit with a repeat cycle coordinated with Terra to facilitate inter-sensor calibration against references such as Pleiades ground truth sites and White Sands Missile Range targets.

Scientific Missions and Applications

ASTER supported investigations in volcanology, glaciology, geology, hydrology, and land-use change. Volcanic monitoring efforts referenced case studies at Mount St. Helens, Krakatoa, Mount Fuji, Mauna Loa, and Eyjafjallajökull, using ASTER thermal bands for anomaly detection. Glaciologists employed ASTER stereo pairs for digital elevation models at Greenland Ice Sheet, Antarctic Peninsula, and Himalaya glaciers. Geologists used mineral mapping techniques to study regions including the Atacama Desert, Death Valley National Park, Zagros Mountains, and Iberian Pyrite Belt. Hydrological applications incorporated ASTER-derived evapotranspiration and soil moisture proxies in basins like the Amazon Basin and Ganges River system.

Data Products and Processing

ASTER produced Level-1 radiance, nadir and backward-looking stereo, digital elevation models, and standardized surface reflectance products. Processing pipelines at NASA Earth Science Data and Information System nodes and JAXA archives applied atmospheric correction methods developed by groups at University of Arizona, University of Maryland, and USGS EROS Center. Users accessed calibrated products alongside ancillary datasets including SRTM elevation, MODIS land cover, and GDEM derivatives. Data distribution leveraged servers and portals used by World Data Center initiatives and coordination with Global Earth Observation System of Systems partners.

Launches and Operational Status

The primary ASTER instrument was launched aboard a platform in December 1999 as part of a larger Earth-observing mission alongside instruments such as CERES and MODIS. During its operational lifetime, instrument operations were coordinated between flight operations centers at JAXA Tsukuba Space Center and NASA Goddard. Periodic anomalies in the SWIR cryocoolers and pointing subsystems led to reduced acquisitions for certain bands, and mission teams from JAXA and NASA implemented mitigation strategies developed in collaboration with contractors like Mitsubishi Heavy Industries. Despite degradations, data continuity was maintained with scheduled calibration campaigns using test sites at Libya 4 and Sahara Desert targets.

Legacy and Impact on Remote Sensing

ASTER left a significant legacy through its digital elevation products and long-term multispectral archive used by researchers at Columbia University, Stanford University, University of Cambridge, ETH Zurich, and Purdue University. The ASTER GDEM influenced subsequent missions such as TanDEM-X and informed algorithms used by Sentinel-2 processing. Its contributions advanced workflows in hazard assessment for agencies like FEMA and informed academic programs at institutions including University of Colorado Boulder and University of British Columbia. The archive continues to support interdisciplinary studies and remains a citation point in literature from journals like Science, Nature, Remote Sensing of Environment, and Journal of Geophysical Research.

Category:Earth observation satellites Category:Remote sensing instruments