The Cubesat-mission industry is evolving rapidly with more performant satellite platforms available (3U, 6U, 12U, or 16U form factors), more diverse launch services (dedicated and rideshare), simplified operations (through the use of existing ground station network), all at reduced cost. This allows new EO and science mission concepts for higher temporal resolution with reduced development time. We present here how a 3x16U Cubesat constellation can provide unprecedented temporal resolution for the monitoring of the Earth magnetic field and the ionospheric environment despite the challenges inherent to that science.
The geomagnetic field has been monitored continuously since 1999 with satellites of masses ranging from 61kg (Orsted) to around 500kg (CHAMP or Swarm). The main challenges of all these missions are the satellite magnetic cleanliness and the coverage required (geographical and in Local Time of the Ascending Node LTAN). The magnetometer requires a very low magnetic noise (less than 1nT) in order to discriminate the geomagnetic sources from the satellite one, which reduces the type of equipment being used and imposes the use of a boom to be further from the satellite's natural magnetic moment. The understanding of the magnetic field requires a global geographical coverage as well as measures from different Local time, making the orbit choices difficult given the current orbits availability (predominantly Sun-Synchronous Orbit). There are two main drivers for the mission design. Firstly, a satellite platform provides a low magnetic environment not to pollute the measurements of the magnetometers. Secondly, a global coverage with a meshgrid of [±6° long. ; ±6° lat. ; ±1.5h Local Time] at least every 3 months for the recovery of electromagnetic waves originating from the core. Such a coverage would be a breakthrough never achieved before in the monitoring of the Earth magnetic field.
Within the framework of the ESA-SCOUT programme, a consortium composed of Open Cosmos (prime), Institut de Physique du Globe de Paris (IPGP as scientific lead), CEA-Leti (payload lead and provider of the magnetometers) and University of Oslo (provider of Langmuir probes and contributing to the associated science) completed the Phase A study of the NanoMagSat mission in Q3 2020 with the collaboration of Comet Ingeniería.
The NanoMagSat mission proposes a 3x16U Cubesat mission with orbits at 575km altitude featuring 2 satellites at 60° inclination offset in RAAN by 90°, and a third satellite at ~87° for coverage of the poles and complementarity with Swarm should it still be operational. The aim is to use dedicated launchers to reach these specific orbits. Each satellite is identical and features a suite of 4 payloads. A Miniaturised Absolute Magnetometer (MAM) co-located with 2 star trackers on an optical bench at the end of a 2-3m boom. A High Frequency Magnetometer (HFM) located at half-mast. A multi-Needle Langmuir Probes (m-NLP) deployed on the front face and two GNSS for TEC and radio-occultations. The 16U platform features a gravity-gradient Attitude and Orbit Control System (AOCS) and subsystems (specifically the Electric Power Supply) optimised for low magnetic signature. The TeleMetry & TeleCommands (TMTC) is using an S-band link, with the data downlink using an X-band. A network of ground stations both in polar and mid-latitude will be used to ensure the download of ~5GB/day/satellite.
The next steps are to de-risk the deployable boom and optical bench together with COMET-Ingenieria, magnetometer electronics and key components, and platform design for low magnetic signature under Risk Retirement Activities to be performed with ESA starting Q1 2022 and to be completed in 2023. The ambition is to confirm the feasibility of this mission under a budget of 30m€ and to be launched within 3 years of KO. This would make NanoMagSat the most cost effective mission in terms of data produced and spatial-temporal coverage ever implemented.
The Earth observation (EO) market which has been driven by the era of smallsat development is expected to have 1,800 smallsats with the majority being less than 50 kg in the next decade. Future EO system is all about getting smaller, more compact with Very High Resolution (VHR) sensor at accessible cost.
This paper will introduce the new generation of a VHR microsatellite constellation developed by Chang Guang Satellite Technology Ltd. of China and commercialized by HEAD. Currently, the DailyVision@1m constellation are composed of six on-orbit JL1-GF03B satellites providing daily revisit globally at 1m resolution. The constellation will be expanded: 35 JL satellites with confirmed launch schedule in 2021 and the full constellation with 138 satellites in 2023, offering global daily revisit of every 14 minutes at 1m resolution.
This microsatellite constellation will be composed of 45 kg State-Of-Art satellites. It is the first < 1m microsatellite and the only one in the market using linear push-boom sensor instead of frame sensors, offering wide swath at 18km instead of market standard at 5 to 6km. The satellite has long strip continuous imaging capacity while traditional satellite imaging processing method is still applicable. The light satellite mass allows low manufacturing and launch cost, a cost-effective solution to operate a constellation.
This future EO constellation introduces technical improvements in optical sensor, propulsion system, deployable solar panels and array antenna. Those existing < 50kg class satellites in the market are usually using CMOS sensors as the optical system required is smaller due to the smaller size of CMOS’s pixel. This new generation of JL satellite is the first 1m microsatellite using CCD sensors which gives significantly better Signal-to-Noise Ratio (SNR) and Modulation Transfer Function (MTF), assuring the quality of the imaging system. High performance and ultra-compact Three Mirror Cassegrain (TMC) optical system is introduced to match the optical requirements from CCD sensors. This 45kg satellite carries propulsion system as well for constellation deployment and maintenance. The satellite is equipped with deployable solar panels generating more power instead of body mounted solar panels, allowing higher imaging capacity at higher downlink up to 600Mbps. In addition, it carries phase array antenna allowing imaging and downlinking simultaneously.
This paper presents the ESA OPS-SAT-2 mission proposal currently within the ARTES 4.0 Strategic Programme Line “Optical Communication – ScyLight”. The mission will follow the OPS-SAT Space Lab concept i.e. launching a series of powerful, reconfigurable flying laboratories for in-flight experimentation not possible, or desirable, on other missions. In-flight experience can be gained very rapidly to ensure that potential future technology works in all operational scenarios (including “on the edge” situations) before it is too late, or too costly, to modify it. Operational experience is gained naturally but due to the healthy risk aversion of operators, it can take decades to complete. OPS-SAT missions accelerate this process. Using a special design and operational expertise, ESA assumes the risk of executing these experiments, thereby releasing industry to concentrate on completing de-risking activities as fast and cost effectively as possible. Each mission concentrates on a different field where the need for rapidly gaining operational experience has been identified.
OPS-SAT-1 is the first satellite in this series. It is also the first nanosatellite owned and controlled by ESA. The chosen field was the many application-level protocols developed for ground-space communications but never flown. The spacecraft was launched in 2019 with GSTP funding and had the aim of testing these protocols in real-world situations. Having successfully demonstrated many new protocols and patents for the first time, it is now providing a cost-free experimenter service for European Industry, education and research institutions. Over 200 of these experiments have been performed originating from other space agencies and major primes to new space entrants and university research groups. The success of OPS-SAT-1 has proven the concept and the plan is to build on that with a second mission.
OPS-SAT-2 is proposed as the second mission in the series and the chosen field is optical and quantum communications. Ground-Space optical links have the potential to completely disrupt many types of space missions, including Earth observation. The high data rates combined with the lack of frequency regulation mean many more ground stations can easily be deployed reducing reaction times and increasing throughput. However, there are many operational challenges that need to be overcome for these missions to reach their full potential. The need for OPS-SAT-2 was identified by space and ground system operators currently working in this area and acknowledging that there is very little operational experience as yet. Besides the opportunity to fly and test hardware, the mission will contribute to mastering these operational challenges, such as how to effectively plan links under variable cloud and turbulence conditions or operational constraints operating from city centres with airports etc. It will also help to identify new market opportunities.
The space segment will be an innovative 12U (or 6U) CubeSat platform developed based on the methodology developed under OPS-SAT-1 that incorporates high-performance COTS subsystems. It will incorporate an optical terminal and quantum source enabling diverse optical ground-space communications and quantum experiments to be performed in flight. At the heart of the satellite will be a state-of-the-art data processing unit (DPU) connected to the optical communications terminal. The DPU consists of a powerful processor and an integrated FPGA which can be reprogrammed in flight. This allows experiments to reconfigure everything on the optical link data layer and employ planning and control algorithms (possibly AI-based) on the processor, to push the system envelope in different operational scenarios. The robustness required to handle the risk involved in changing on-board software and firmware on a daily basis is provided by the Space Lab system design, i.e. two control systems in the same structure, each able to monitor each other.
On the space side, autonomous approaches for acquiring and re-acquiring the optical link on-board when faced with different cloud and atmospheric turbulence conditions will be tested and validated. Variable and semi-real time adaptive data rates to optimise the data rate during the pass over the optical ground station and pushing to low elevation angles will be tested. The transmission of a quantum channel together with the optical communication channel will enable the early characterisation of solar and blue-sky background and straylight light issues when detecting single photons.
On the ground side, early operational testing and validation of the different optical ground stations coming on to the market will be performed. This includes portable ground stations placed in different environments such as city centres or near airports. The availability of a beacon in space will support the development and validation of models for the characterisation and understanding of optical transmission through atmospheric turbulence.
On the system side, the mission was identified as a unique opportunity to perform atmospheric transmission characterisation at different aspect angles from low Earth orbit. Also, new ways of planning optical communication links are certainly going to be required in the future and they need to be tested under real-world conditions. The variability of cloud cover over the geographical areas targeted by optical and quantum missions for their main markets means classic planning systems used in RF missions will no longer work. An autonomous, distributed, networked system with intelligent nodes on the spacecraft and the ground terminals will be required to solve this time varying problem. OPS-SAT-2’s DPU will play a critical role in trying out different strategies using Machine Learning and AI.
An ESA Concurrent Design Facility (CDF) study was run in July/August 2021 to assess the feasibility of such a mission. The CDF team recommended a 12U CubeSat, which would release resources for additional payloads preferable in the optical domain. Another conclusion was that significant performance of the ADCS and GNSS subsystems was required to handle the pointing requirements of such a mission. This paper will describe the mission status and design.
Optical imaging spectroscopy opens the doors to an incredibly wide range of atmospheric, land, and ocean Earth observation applications. Historically, this technology has only been available on a limited number of spaceborne systems, creating a wide gap between well-developed remote sensing science and the availability of high quality, analysis ready data to which it can be applied. Recent advances in imaging spectrometer technology, along with innovative new public-private partnerships, are poised to change the status quo, drive scientific progress in Earth observation, and impact global initiatives for critical socio-economic and sustainability goals.
The Carbon Mapper mission, a low Earth orbit hyperspectral constellation set to launch its first two imaging spectrometers in 2023, is being developed through a strong public-private partnership among several collaborators, including Carbon Mapper, Planet, NASA Jet Propulsion Laboratory (JPL), Arizona State University, the University of Arizona, the High Tide Foundation, California Air Resources Board, and the Rocky Mountain Institute. Using cutting-edge, best-in-class, imaging spectrometer technology, JPL and Planet will build the initial payloads, and Planet will launch, operate, and expand the constellation in future mission phases. These sensors will be operated at ~400 km orbit altitude, will have a spatial resolution of 30 m, and will measure the spectral range 400-2500 nm with contiguous 5 nm sampling. The satellites will be tasked, and the full constellation will aim for a 1-7 day revisit for imaging. Because the primary focus for the mission will be the detection and mapping of methane and CO2 emissions, the instruments will have a very high signal-to-noise ratio (SNR) in the infrared, enabling strong sensitivity to these greenhouse gases. Beyond these applications, imaging spectroscopy scientists at Arizona State University will work to develop initial land and ocean data products to support the mission.
This mission is strongly positioned to advance the operationalization and broader usability of imaging spectroscopy data. Being a fully taskable constellation, it can provide timely, targeted acquisition of imagery over key parts of the Earth’s surface and coordinate collections with other missions and ground data collections. A streamlined calibration and validation pipeline will enable the creation of high quality analysis ready data products that are easy for users to incorporate into their analytics workflows and have been validated extensively within the scientific community. This constellation will also complement Planet’s existing high-spatial and high-temporal resolution constellations. Cross-sensor interoperability and harmonization will enable the development of novel HSI fusion products with both Planet and other publicly available satellite data to unlock new applications and address some of the most difficult mapping and monitoring challenges facing the world today.
The oceans make this planet habitable and provide a variety of essential ecosystem services ranging from climate regulation through control of greenhouse gases to provisioning about 17% of protein consumed by humans. The oceans are changing as a consequence of human activity and yet because our knowledge about this ecosystem is limited, we cannot accurately model and predict how it will behave in the future. The oceans are vast, occupying almost 71% of our planet’s surface and yet less than 10% of it has been studied. This system is severely under sampled and despite breathtaking advances in observational technology, robotics, and computer science, we have not addressed the mismatch in the scales of observation needed and our traditional ways of studying the ocean. The absence of a reliable, efficient, and rapid monitoring system for ocean health is greatly impeding our capacity to respond to and prevent human-induced threats in a timely, context-relevant and effective way.
There is, an urgent need for a reliable, efficient, and affordable data-gathering, assimilating and ocean modeling capability to help scientists monitor, understand, and effectively manage key processes that are essential to ocean health and negatively impacted by human activity. Based on our team's combined knowledge and experience in this field, we believe that an integrative ocean-management approach, and the protection of our ocean capital can only be achieved with the help of coordinated observations from space and aerial, surface and underwater robots guided by Artificial Intelligence (AI), principled machine learning, and physics-based probabilistic modeling. We are proposing this innovative and first-of-its-kind (hardware and software) solution by building a portable robotic observatory that can be rapidly deployed anywhere in the world for efficient observing, analyzing and evaluating the health of our endangered coastal waters.
METEOR (Movable ocEan roboTic obsErvatORy) is conceived as a modular system with bespoke approaches related to water quality in the world’s coastal zones. The fully completed observational system will constitute both a vertical integration of state-of-the-art hardware
including a small satellite constellation, as well as in-situ air, surface and underwater vehicles, with innovative software and assimilating ocean models to visualize the information gathered and predict the near term future, as well as horizontal integration across disciplines of computer science, marine robotics, engineering, risk quantification, ocean modeling, and oceanography. The frequent revisit times over a region that only a constellation of SmallSat’s can provide, coupled with the latest smart and adaptive AI techniques, will enable robots to deliver systematic and opportune observations of parameters relevant to coastal water quality and ocean processes in near real-time.
The components of METEOR include a relocatable modeling system provides unique capabilities in multi-scale physical-biogeochemical-acoustical ocean modeling, probabilistic forecasting, data assimilation, and Bayesian inference which will help guide an ensemble of autonomous platforms towards the most informative observations. Well proven embedded and on-shore AI-driven decision-making algorithms, combined with expertise in coastal bio-geochemical dynamics can then ensure that these in-situ platforms in the air, surface and underwater domains, can observe and make the right measurements, at the 'right place and time’ at scale, a key missing ingredient in current observational systems.
Traditional and current methods for observing the coastal ocean are inefficient, too sparse in space and sporadic in time, or too localized. There is poor integration and assimilation of multiple data sources - especially between those made in-situ and those made by satellites - to produce actionable knowledge.
METEOR is different as it leap-frogs current methods by delivering advanced predictive modeling, Machine Learning and AI-driven analytical capabilities, augmented by visualization techniques that optimize observations but are non-existent in other interventions. The density and diversity of observations will change by an order of magnitude; the temporal scales of coastal observations will change from weeks or days to hours and minutes with the provision of near real-time information. Current remote sensing observations are available at best once a day, while with a SmallSat constellation we can provide better quality data every 3 hours at any fixed point in the coastal zone. The SmallSat constellation in addition can be leveraged for other projects such as monitoring global water quality in lakes and reservoirs as well as provide rapid response capability to events in other water bodies at any time. Techniques in AI will adapt the information for dissemination depending on the kind of user, from well-informed scientists or government officials to the lay person curious about how beach conditions might impact their leisure. The information will also be delivered via an app on a smartphone or tablet and will be freely available to registered users.
In the process of providing actionable knowledge, METEOR will enable new modes of management and new understanding about coastal ocean processes in ways simply not possible before. While prototypes of systems that combine remote sensing with ocean models exist, most of these systems do not provide the kinds of near real-time information at spatial scales (10s--100s of meters) relevant to coastal managers or citizens. METEOR will overcome this challenge by combining intelligently deployed in-situ sensors with high resolution (~100m) satellite data and assimilating ocean models to produce layers of data of increasing complexity accessible to everyone from citizens on the beach to scientists. METEOR will allow citizens to develop critical understanding of the rapid changes taking place in their urban oceans/seas and to connect the dots between human activity and the effect on the environment around them. Citizen scientists will be engaged in
generating new observations and be able to derive new knowledge about how ocean processes work. Scientists will be able to pose and address new questions that could not have been asked before, and policymakers will have the tools to make informed decisions in time scales that matter, while developing truly integrative policies on ocean sustainability and stewardship.