An Autonomous Earth - Observing Sensorweb

The need Although the South Sandwich Islands are uninhabited, NASA’s Terra and Aqua satellites fly overhead four times per day, skimming past at 7.5 kilometers per second and an altitude of 705 kilometers. Each spacecraft carries a Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, which acquires resolution data of 250 to 1,000 meters/pixel about the islands as part of a 2,700-kilometer-wide swath of imagery. Streamed to Goddard Space Flight Center (GSFC), these data are processed at the Distributed Active Archive Center (DAAC) where MODVOLC (MODIS VOLCano Thermal Alert System) algorithms developed at the University of Hawaii (http://modis.higp.hawaii.edu) automatically detect the volcanic activity’s hot-spot signature within hours of data acquisition. Software monitoring the MODVOLC Web site matches this new alert with a previously specified science team interest in volcanoes in this region, generating an observation request to the Earth Observing One (EO-1) ground system. Based on the request’s priority, the ground system uplinks the observation request to the EO-1 spacecraft. Onboard AI software evaluates the request, orients the spacecraft, and operates the science instruments to acquire high-resolution (up to 10 m/pixel) images with hyperspectral (220 or more bands) data for science analysis. Onboard, EO-1 processes this data to extract the volcanic eruption’s signature, downlinking this vital information within hours. A wide range of operational satellites and space platforms make their data freely available, via either broadcast or the Internet, usually within from tens of minutes to several hours from acquisition. For example, data from the MODIS flying on the Terra and Aqua spacecraft are available via direct broadcast in near-real-time for regional coverage and from 3 to 6 hours from acquisition from Goddard’s DAAC for global coverage. These data provide regional or global coverage with a wide range of sensing capabilities: MODIS covers the globe roughly four times daily (two day and two night overflights), while NASA’s Quick Scatterometer (QuickSCAT) covers the majority of the globe daily. Unfortunately, these global-coverage instruments don’t provide the high-resolution data many science applications require. Their resolution ranges from 250 m to 1 km for the MODIS instruments to 1 km and above for the other instruments. Ideally, high-resolution data would be available continuously with global coverage. High-resolution assets typically can image only limited swathes of the Earth, making them highly constrained, high-demand assets. In our sensorweb application, sensors, science event recognizers, and trackers are networked with an automated Near Antarctica, in a remote area of the South Atlantic Ocean, a volcano rumbles. Following a few