Integrating Globally Dispersed Calibration in Small Satellites Mission Value

The availability of earth observation (EO) data has rapidly increased from small satellite missions, however, there are often important deficiencies in its accuracy due to lack of calibration. If calibration is rigorously used with emerging sensors, there can be important improvements in reducing uncertainty with profound implications in use of remote sensing data for climate modeling, disaster recovery, and other applications. Here, a novel methodology for modeling the value of multi-spacecraft earth observation missions with globally dispersed calibration systems for frequent radiometric calibration of earth imaging sensors is presented. The mission value is quantified with a proxy metric, Effective Data Acquired (EDA), which is the total data returned by the system for regions of interest to data users over the operational life of the EO system. The EDA is adjusted with calibration-related discounting factors determined by the rate at which data accuracy declines and the frequency of recalibration for each sensor. The method is demonstrated for small spacecraft constellations for earth imaging. The simulated results, for the specific case, show that the adjusted-EDA is reduced by ~18% (from ~2900 TB to~2400TB) for a degradation rate of 0.05% over a 60-day time period. Overall, the adjusted-EDA can be used for relative comparisons in trade studies with varying mission design and calibration site and frequency parameters

BeaverCube: Coastal Imaging with VIS/LWIR CubeSats

BeaverCube is a student-built 3U CubeSat that has two main objectives: one science objective and one technology objective. The science goal of BeaverCube is to demonstrate that it is possible to develop and apply platforms that can leverage statistical relationships between temperature and co-varying bio-optical properties, such as light absorption by colored dissolved organic matter. The technology goal of BeaverCube is to demonstrate electrospray propulsion for CubeSats, enabling more coordinated and targeted science missions among multiple spacecraft. The science objective for BeaverCube involves measuring temperature and color, which are key oceanographic properties, through a low-cost platform. Temperature and salinity are used to determine the density of watermasses. This is then used to physically classify them. Thermohaline circulation is a part of large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. Thermohaline circulation plays an important role in supplying heat to the polar regions; it influences the rate of sea ice formation near the poles, which in turn affects other aspects of the climate system, such as the albedo, and thus solar heating, at high latitudes. Small- and meso-scale ocean features such as fronts and eddies canal so be identified and tracked solely using sea surface temperature properties. BeaverCube will track warm core rings on the Northeastern section of the US coast, one of the regions in the world that is heating the fastest due to climate change. Wide geospatial coverage with near-simultaneous measurements of thermal and bio-optical ocean properties by a CubeSat has the potential to address many important oceanographic questions for both basic science and Naval applications. The majority of space-borne optical oceanographic parameters observed from CubeSats rely on atmospheric corrections to provide useful data. BeaverCube will both obtain data and help determine to what extent supplemental data will still be required for atmospheric corrections. BeaverCube will make sea surface and cloud top temperature measurements using three cameras: one visible and two FLIR Boson LWIR cameras. In-situ measurements will be coordinated with an array of ocean buoys to support calibration and validation. The student team successfully tested the LWIR camera on a high-altitude balloon launch in November 2019 to an altitude of 110,000 feet, demonstrating the imaging functionality in a near-space environment. The technology goal for BeaverCube is to demonstrate the operation of the Tiled Ionic Liquid Electrospray (TILE2) propulsion technology from Accion Systems, Inc. for orbital maneuvering. BeaverCube will be deployed in Low Earth Orbit from the International Space Station. The plan is to change the altitude of BeaverCube by 480 meters using 50 micro-Newtons of thrust, detected by an onboard GPS receiver. With a goal of launching in late 2020 or early 2021, BeaverCube passed Critical Design Review in Spring 2020, with subsystems designed and procured, including components from AAC Clyde Space (power), ISIS (ADCS), Near Space Launch (BlackBox with GlobalStar simplex radio and NovAtel GPS), and others (OpenLST radio and Raspberry Pi based C&DH board). Assembly and integration prior to environmental testing are planned for late summer 2020

The Impact of Radiometric Calibration Error on Earth Observation-supported Decision Making

Earth Observation through satellites enables decision makers to assess situations near real-time with unprecedented spatial coverage. The data-value added products from radiometric satellite images often use indices derived from the unique spectral properties of materials and are sensitive to the relative gains of the different bands of the satellite sensor. However, satellite sensors are susceptible to degradation from the space environment, leading to drift in band response. For well-calibrated satellites such as Landsat 8, these drifts are well characterized and can be corrected for during processing—however, for satellites lacking on-board calibration (such as CubeSats), these trends can be difficult to detect and require novel methods combining cross calibration with machine learning. Given that satellite data often undergoes several levels of processing prior to use, there is a need to quantify the relationship between calibration errors and the errors of the final data-valued added product. This study investigates two applications of Earth Observation data: crop classification and Harmful Algal Bloom detection, and quantifies the impact of induced radiometric error on the final data product.S.B

Valuation of Calibration for Satellite Constellations

Earth observation systems, consisting of in-space and air borne platforms and sensors, are providing a growing number of high resolution spatial and temporal services including agricultural crop yield predictions, local weather forecasts, and traffic management. As the complexity of these systems increases with multi-platform elements and sophisticated processing and modeling, there are also increasing avenues for introduction of errors. It is important to characterize and quantify the uncertainties and errors. Here, it shown that a value-chain approach can be used for conceptualizing errors and modeling uncertainties relevant for final decisions. This approach can then be applied for improving system value assessments and obtaining an ‘error-adjusted’ value of the remote sensing system. The error-adjusted value can be used in optimization or trade-studies for system design. This value system is then applied, as an example, to the FLARE real world calibration/validation system to look at potential Return on Investment (ROI) of better calibration to satellite image prices and market penetration

MarsGarden: Designing an ecosystem for a sustainable multiplanetary future

Exploration of space has always held a certain fascination for humankind. Stepping foot on the Moon may have been the achievement of the century, and sending humans to Mars will be even more challenging and exciting. To achieve self-sufficiency off the Earth, humans will need a steady supply of food while also maintaining adequate mental health. We propose here a closed-loop ecosystem that accomplishes both while being feasible to transport, construct, and maintain on Mars. The resulting design, MarsGarden, is capable of providing a crew of four astronauts with all their dietary needs and also acting as a place of relaxation and restoration. MarsGarden is a scalable architecture that can be adapted to many deep space environments, or can be implemented on Earth as an agricultural solution for areas with land scarcity or extreme environments.