On Small Satellites for Oceanography: A Survey

The recent explosive growth of small satellite operations driven primarily from an academic or pedagogical need, has demonstrated the viability of commercial-off-the-shelf technologies in space. They have also leveraged and shown the need for development of compatible sensors primarily aimed for Earth observation tasks including monitoring terrestrial domains, communications and engineering tests. However, one domain that these platforms have not yet made substantial inroads into, is in the ocean sciences. Remote sensing has long been within the repertoire of tools for oceanographers to study dynamic large scale physical phenomena, such as gyres and fronts, bio-geochemical process transport, primary productivity and process studies in the coastal ocean. We argue that the time has come for micro and nano satellites (with mass smaller than 100 kg and 2 to 3 year development times) designed, built, tested and flown by academic departments, for coordinated observations with robotic assets in situ. We do so primarily by surveying SmallSat missions oriented towards ocean observations in the recent past, and in doing so, we update the current knowledge about what is feasible in the rapidly evolving field of platforms and sensors for this domain. We conclude by proposing a set of candidate ocean observing missions with an emphasis on radar-based observations, with a focus on Synthetic Aperture Radar.Comment: 63 pages, 4 figures, 8 table

Selection of the key earth observation sensors and platforms focusing on applications for Polar Regions in the scope of Copernicus system 2020-2030

An optimal payload selection conducted in the frame of the H2020 ONION project (id 687490) is presented based on the ability to cover the observation needs of the Copernicus system in the time period 2020–2030. Payload selection is constrained by the variables that can be measured, the power consumption, and weight of the instrument, and the required accuracy and spatial resolution (horizontal or vertical). It involved 20 measurements with observation gaps according to the user requirements that were detected in the top 10 use cases in the scope of Copernicus space infrastructure, 9 potential applied technologies, and 39 available commercial platforms. Additional Earth Observation (EO) infrastructures are proposed to reduce measurements gaps, based on a weighting system that assigned high relevance for measurements associated to Marine for Weather Forecast over Polar Regions. This study concludes with a rank and mapping of the potential technologies and the suitable commercial platforms to cover most of the requirements of the top ten use cases, analyzing the Marine for Weather Forecast, Sea Ice Monitoring, Fishing Pressure, and Agriculture and Forestry: Hydric stress as the priority use cases.Peer ReviewedPostprint (published version

The status of environmental satellites and availability of their data products

The latest available information about the status of unclassified environmental satellite (flown by the United States) and their data products is presented. The type of environmental satellites discussed include unmanned earth resource and meteorological satellites, and manned satellites which can act as a combination platform for instruments. The capabilities and data products of projected satellites are discussed along with those of currently operating systems

Constellation Design of Remote Sensing Small Satellite for Infrastructure Monitoring in India

A constellation of remote sensing small satellite system has been developed for infrastructure monitoring in India by using Synthetic Aperture Radar (SAR) Payload. The low earth orbit (LEO) constellation of the small satellites is designed in a way, which can cover the entire footprint of India. Since India lies a little above the equatorial region, the orbital parameters are adjusted in a way that inclination of 36 degrees and RAAN varies from 70-130 degrees at a height of 600 km has been considered. A total number of 4 orbital planes are designed in which each orbital plane consisting 3 small satellites with 120-degrees true anomaly separation. Each satellite is capable of taking multiple look images with the minimum resolution of 1 meter per pixel and swath width of 10 km approx. The multiple look images captured by the SAR payload help in continuous infrastructure monitoring of our interested footprint area in India. To support the mission, each small satellite is supplied with earth sensors, sun sensors, GPS to accurately determine its position and attitude, and Control Moment Gyro (CMGs) which is capable of high slew rate maneuver with precise pointing at minimum power utilization. Further, each small satellite is equipped with a communication payload that uses X-band and VHF antenna, whereas the TT&C will use a high data-rate S-band transmitter. The satellite requires a powerful set of batteries to operate along with an origami-designed solar panel with the implementation of GaN-FETs to improve the performance and efficiency of solar power conversion. The paper presents only a coverage metrics analysis method of our designed constellation for our India footprint by considering the important metrics like revisit time, response time, and coverage efficiency. The data processing for the captured images is not presented here. The result shows that the average revisits time for our constellation ranges from about 15-35 min which is less than an hour and the average response time for this iteratively designed constellation ranges from about 25-120 min along with hundred percent coverage efficiency most of the time. Finally, it was concluded that each satellite has 70kg of total mass and costs around $ 0.75M to develop

Support for global science: Remote sensing's challenge

Remote sensing uses a wide variety of techniques and methods. Resulting data are analyzed by man and machine, using both analog and digital technology. The newest and most important initiatives in the U. S. civilian space program currently revolve around the space station complex, which includes the core station as well as co-orbiting and polar satellite platforms. This proposed suite of platforms and support systems offers a unique potential for facilitating long term, multidisciplinary scientific investigations on a truly global scale. Unlike previous generations of satellites, designed for relatively limited constituencies, the space station offers the potential to provide an integrated source of information which recognizes the scientific interest in investigating the dynamic coupling between the oceans, land surface, and atmosphere. Earth scientist already face problems that are truly global in extent. Problems such as the global carbon balance, regional deforestation, and desertification require new approaches, which combine multidisciplinary, multinational research teams, employing advanced technologies to produce a type, quantity, and quality of data not previously available. The challenge before the international scientific community is to continue to develop both the infrastructure and expertise to, on the one hand, develop the science and technology of remote sensing, while on the other hand, develop an integrated understanding of global life support systems, and work toward a quantiative science of the biosphere

Demonstration of a Heterogeneous Satellite Architecture During RIMPAC 2018

The Micro-Satellite Military Utility (MSMU) Project Arrangement (PA) is an agreement under the Responsive Space Capabilities (RSC) Memorandum of Understanding (MOU) involving the Departments and Ministries of Defence of Australia, Canada, Germany, Italy, Netherlands, New Zealand, Norway, United Kingdom and United States. MSMU’s charter is to inform a space enterprise that provides military users with reliable access to a broad spectrum of information in an opportunistic environment. The MSMU community participated on a non-interference basis in the biennial Rim of the Pacific (RIMPAC) exercise from 26 June to 2 August 2018. This provided an opportunity to explore the military utility of a heterogeneous space architecture of satellites including traditional government and commercial satellites, as well as micro-satellites and nanosatellites associated with the “new space” paradigm. The objective was to test the hypothesis that a heterogeneous space architecture, mostly composed of small satellites, can bring significant value to the operational theatre. This paper describes the results from the MSMU experiment, outlines the lessons learned in terms of the infrastructure required to support such an experiment, and offers insights into the military utility of the heterogeneous space architecture. It concludes that a cooperative heterogeneous space architecture does have advantages and value, and that micro-satellites and nanosatellites contribute significant capability

A New Orbiting Deployable System for Small Satellite Observations for Ecology and Earth Observation

In this paper, we present several study cases focused on marine, oceanographic, and atmospheric environments, which would greatly benefit from the use of a deployable system for small satellite observations. As opposed to the large standard ones, small satellites have become an effective and affordable alternative access to space, owing to their lower costs, innovative design and technology, and higher revisiting times, when launched in a constellation configuration. One of the biggest challenges is created by the small satellite instrumentation working in the visible (VIS), infrared (IR), and microwave (MW) spectral ranges, for which the resolution of the acquired data depends on the physical dimension of the telescope and the antenna collecting the signal. In this respect, a deployable payload, fitting the limited size and mass imposed by the small satellite architecture, once unfolded in space, can reach performances similar to those of larger satellites. In this study, we show how ecology and Earth Observations can benefit from data acquired by small satellites, and how they can be further improved thanks to deployable payloads. We focus on DORA—Deployable Optics for Remote sensing Applications—in the VIS to TIR spectral range, and on a planned application in the MW spectral range, and we carry out a radiometric analysis to verify its performances for Earth Observation studies

Earth Observing System. Science and Mission Requirements, Volume 1, Part 1

The Earth Observing System (EOS) is a planned NASA program, which will carry the multidisciplinary Earth science studies employing a variety of remote sensing techniques in the 1990's, as a prime mission, using the Space Station polar platform. The scientific rationale, recommended observational needs, the broad system configuration and a recommended implementation strategy to achieve the stated mission goals are provided

Guidelines for spaceborne microwave remote sensors

A handbook was developed to provide information and support to the spaceborne remote sensing and frequency management communities: to guide sensor developers in the choice of frequencies; to advise regulators on sensor technology needs and sharing potential; to present sharing analysis models and, through example, methods for determining sensor sharing feasibility; to introduce developers to the regulatory process; to create awareness of proper assignment procedures; to present sensor allocations; and to provide guidelines on the use and limitations of allocated bands. Controlling physical factors and user requirements and the regulatory environment are discussed. Sensor frequency allocation achievable performance and usefulness are reviewed. Procedures for national and international registration, the use of non-allocated bands and steps for obtaining new frequency allocations, and procedures for reporting interference are also discussed

A Novel Method for Achieving SAR Imaging with a Pair of Micro-Satellites by Means of a Bi-Static Configuration

There is increasing interest in the potential capabilities and applications of micro -satellites in the field of Earth-observation (EO). Passive optical imaging is now well established on such platforms, however, an active imaging payload - a synthetic aperture radar (SAR) - would appear to be insupportable, due to its size, complexity and high -power requirements. A major driver of these requirements is that traditional SAR systems use backscatter - which is necessarily weak from most terrain types. If the forward scattered energy could be gathered, then the transmit-power requirements could drop significantly. We therefore propose a novel method by which two micro-satellites fly in formation to accomplish a SAR mission bi-statically. The transmitting satellite will be the “master”, with the receiver satellite “slaved” off it by means of a synchronization signal. The satellites image a swath of 30 km, at a ground resolution of 30 m from 700 km altitude. Our constellation geometry can image anywhere in a pre-selected latitude band, and requires minimal orbit-control resources. The viewing configuration resolves the left-right ambiguity that occurs in near nadir pointing bi-static radar. Applications to a polar ice-monitoring mission are discussed, although with minor changes any location on Earth can be viewed