Earth observations from space demonstrate the successful synergy between science and technology. As scientists have gained experience in studying Earth through satellite observations, they have defined new technological needs, helped drive technological development to provide more quantitative and accurate measurements, and have advanced more sophisticated methods to interpret satellite data. To capitalize fully on the investment made in Earth-orbiting observing platforms and make the best use of these observations, satellite data require careful calibration and sophisticated analysis and assimilation tools. Optimal data processing can be undertaken only if a suitably trained workforce is in place to develop these tools and interpret the observations. In this respect, full and open access to satellite data is crucial because training and maintaining the required workforce is possible only if the data are continuously accessible to the broad scientific community.

The concept of open data access was adopted by the IGY when establishing the World Data Center System 50 years ago, and it is even more meaningful today than at the time of the Cold War. This does not preclude commercialization of some aspects of useful data product development, but the portion of carefully calibrated low-level data that is properly a public good should be made available to all stakeholders at no more than the cost of reproduction. The Landsat story is a case in point: wholesale commercialization of the data led to a precipitous drop in their use for both scientific and commercial applications, which recovered upon return to the earlier open data access policy. Only when academic, government, and commercial scientists are given liberal access to the data, and when a sufficient number of scientists are trained in the effective use of these data, will the analysis tools mature to the benefit of all parties. Our 50-year experience with passive (e.g., optical) and active (e.g., radar or lidar [light detection and ranging]) surface imagery, weather satellites, and planetary field measurements shows that the maturation process of these tools requires decades.

The first 50 years of Earth observations from space imparted the fundamental lessons that everything—land, ocean, and atmosphere—is intricately intertwined and that the Earth is a complex and dynamic system. In addition, “each [satellite] mission taught scientists not only something new about the Earth system, but also something new about how to create, operate, and improve the technology for observing the Earth from space.”⁴

Based on its review of important scientific accomplishments, the committee concludes the following (for a detailed description, see Chapter 12):

1. The daily synoptic global view of Earth, uniquely available from satellite observations, has revolutionized Earth studies and ushered in a new era of multidisciplinary Earth sciences, with an emphasis on dynamics at all accessible spatial and temporal scales, even in remote areas. This new capability plays a critically important role in helping society manage planetary-scale resources and environmental challenges.

2. To assess global change quantitatively, synoptic data sets with long time series are required. The value of the data increases significantly with seamless and inter-calibrated time series, which highlight the benefits of follow-on missions. Further, as these time series lengthen, historical data sets often increase in scientific and societal value.

3. The scientific advances resulting from Earth observations from space illustrate the successful synergy between science and technology. The scientific and commercial value of satellite observations from space and their potential to benefit society often increase dramatically as instruments become more accurate.

4. Satellite observations often reveal known phenomena and processes to be more complex than previously understood. This brings to the fore the indisputable benefits of multiple synergistic observations, including orbital, suborbital, and in situ measurements, linked with the best models available.

5. The full benefits of satellite observations of Earth are realized only when the essential infrastructure, such as models, computing facilities, ground networks, and trained personnel, is in place.

6. Providing full and open access to global data to an international audience more fully capitalizes on the investment in satellite technology and creates a more interdisciplinary and integrated Earth science community. International data sharing and collaborations on satellite missions lessen the burden on individual nations to maintain Earth observational capacities.

7. Over the past 50 years, space observations of the Earth have accelerated the cross-disciplinary integration of analysis, interpretation, and, ultimately, our understanding of the dynamic processes that govern the planet. Given this momentum, the next decades will bring more remarkable discoveries and the capability to predict Earth processes, critical to protect human lives and property. However, the nation’s commitment to Earth satellite missions must be renewed to realize the potential of this fertile area of science.

Because the critical infrastructure to make the best use of satellite data takes decades to build and is now in place,