Enhanced Temporal Repeat Coverage at Landsat-like Resolution - a Low-cost, Small-sat Mission Concept

Landsat images have been used to document land cover and land use change since 1972, spanning a period when global populations have more than doubled, and associated land transformations have increased at an escalating rate. This 38-year Landsat global archive constitutes perhaps the most valuable global change / climate data record available to the world. In late 2008, the USGS EROS Center implemented a decision to make their deep archive of Landsat imagery available to the world community free of charge. In less than two years following that implementation of a free data policy, well over three million scenes have been downloaded and analyzed by thousands of users from 186 different countries. A bulk of the resulting image analyses has been focused on using the Landsat archive for inter-annual assessments to monitor change over time. The often dramatic change detection results have served to heighten interest in not only maintaining the continuity of Landsat imaging, but in increasing the temporal repeat frequency to obtain more robust “within season” assessment capability. The scientific utility of dramatically improved temporal repeat coverage, permitting scientists to assess the nuances of within season fluctuations in productivity at 30 m resolution, anywhere on the globe, is clearly breathtaking. Sadly, the prospect of maintaining, let alone improving upon, the 8-day temporal repeat coverage provided by Landsat’s 5 and 7 over the last decade will be hard to realize due to the escalating production costs associated with building these high precision missions (i.e., $1B). There is a need to look for dramatically lower cost options to augment, but not replace, the classic Landsat missions. A group of Earth scientists affiliated with NASA’s Goddard Space Flight Center have taken a fresh look recently at developing a low-cost, small-sat Landsat-like imaging concept. Their goal has been to derive a cost-effective alternative solution that can provide imagery of sufficient quality and quantity to augment global Landsat coverage. The effort to develop and advance this mission concept has been named LOGICAL, for Land Observations Globally In a Cost-effective Augmentation of Landsat. The approach that is being used to develop the concept will be presented, along with preliminary findings that indicate that such a mission is doable at a cost that is as much as an order of magnitude less expensive than a typical “gold standard” Landsat mission in today’s aerospace environment. If such a mission concept could be realized, it would not only serve to dramatically enhance scientific applications, but it would also reduce the risk of a devastating gap in Landsat-like imaging capability.