Nigel Fox, an NPL Fellow at the National Physical Laboratory, discusses a climate-focused Truths Mission, including the results so far and the benefits offered for the future.
Trackable radiometry supporting ground and helio research (truth) satellite missions, in collaboration with several European states led by the UK Space Agency (UKSA), is designed to improve climate change modeling.
The truth provided by the European Space Agency sets a “gold standard” reference for climate measurement, and becomes the “Space Standards Laboratory.” Carrying cryogenic solar absolute radiometers and hyperspectral imaging spectrometers, the truth, like new onboard calibration systems, continuously measures incoming solar and reflected radiation to assess the Earth’s energy and energy ratio.
To learn more about the missions and progress made so far, the Innovation Platform devised the mission and spoke to its leading investigator, Nigel Fox, NPL Fellow of Light Radiometric and Earth Observation at the National Institute of Physics (NPL).
Can you briefly outline Truths Mission, its main collaborators, and its important objectives?
Truths is a UK proposal and is derived from the ESA Earth Watch Mission, providing hyperspectral analysis-enabled data (ARD) of incident and Earth/Moon solar radiation in the unprecedented short wave (UV-SWIR) spectral range.
The resulting data serves as a reference benchmark for the short wave states of the planet. The planet’s short wave state is a signature of “vegetation/air quality” (vegetation/water quality, mineralogy, mineral gas, etc.) such as vegetation, aerosol/air type/health, land/water pollution, minerals, greenhouse gases, and other emissions, and serves as a reference benchmark for the planet’s short wave states that can reliably detect near and long-term changes.
Truths’ “Gold Standard” reference data not only serves the Earth Observation (EO) community through its own data, but also uniquely upgrades the entire Earth Observation System through the provision of reference calibrations. The mission will directly respond to the requirements of the Earth Observation Satellite Committee (CEO) and the Global Climate Observation System (GCOS).
mission:
Climate measures/mitigation outcomes can be assessed in a robust way on the shortest possible timescale to ensure timely evidence-based adaptation investments. It promotes improved parameterization of climate models, including carbon cycles, radiation imbalances, and reduced climate uncertainty and impact predictions. A harmonious satellite observation system with reduced uncertainty and increased reliability will allow you to maximize the value of money for all space assets in the world. It provides a means of reliably integrating high spatial/temporal resolution commercial satellite data into mainstream scientific observation systems, leading to new localized information services. In principle, it enables the creation of new innovative services and associated economic growth through UK data architectures such as EODH.
By providing high accuracy of existing infrastructure such as Moon and Earth’s Desert, the truth extends the value of the mission back and forth beyond the nominal lifespan of 5-8 years. By enabling realignment and harmonization of existing data for the 1980s and future missions, artificial intelligence (AI) tools and digital twins will fully utilize the archives of global data, allowing truths with effective lives and impacts to become missions.
The mission is carried out by the ESA and is funded by a consortium of European countries led by the UK (funded by Spain, Switzerland, Greece, Romania and the Czech Republic).
The Mission Development Consortium is led by Airbus UK and is comprised of a variety of companies (approximately 25, small and medium-sized businesses), including Telespagio UK, CGI, SSTL, AVS-UK, RAL Space, NPL, Deimos-UK & Romania, Teledin-UK, Thales Alenia Space Plants, switzerland, switzerland, seederland, thales-switzerland, seederland, teledyne-uk & Romania. Republic, Sonvision Romania, ISD Greece, and Helia Photonics Ltd.
What are the issues related to the current capabilities of the EO system? Also, how does the truth work to improve these?
Most existing satellites provide data within their individual specifications. However, these are often appropriate when stored independently for individual applications on a particular mission, but there is often bias between similar missions from different space agencies, or similar missions from the same space agency between different satellite sensors. In many cases, these differences do not necessarily pose important issues until data from different sensors must be combined together to create long-term base studies. For example, it is required for services that require results from two or more satellites to improve sampling. In these cases, biases need to be evaluated and eliminated by potentially harmonizing with one sensor. But which one?
Similarly, when absolute values of change are required, it is important that all world satellites have common references that could be derived and derived to the consensus information needed to support climate action, support financial risks, and address the issues of potential litigation. The more confident (accurate) your data is, the more reliable and reliable your information and behavior.
In many climate applications, the signal/trends detected are very small, which can take decades as it is a device that is performing measurements at a level sufficient to confidently detect background noise throughout the Earth system. Research shows that the uncertainty requirements for many years of climate observation are typically about 10 times lower than current sensors achieve.
However, the main challenge of the current observation system is residual bias and how to establish a common reference that depends on the present and future and can be accepted by all. International Unit Systems (SIs) are, in principle, designed to do this, with most satellites trying to adjust to this system before launching. However, although every effort is made to ensure that data from satellites is accurate, the impact and spatial harshness of the launch generally leads to a largely small, performance change that must be evaluated and corrected before exploiting the data.
Many published EO satellite missions tend to be sized enough to have their own onboard calibration system that helps to deal with changes in performance, such as bias. However, the onboard system may also be subject to change. Typical satellites in commercial organizations generally do not have the ability to host such systems and rely solely on calibration/validation for subrogatively viewed references such as deserts. Public sector missions rely on first flight calibration checks on deserts and similar targets for onboard system drift, contributing to continuous monitoring.
These challenges limit the uncertainty that can be achieved during flight to at most about 2-3%, and often significantly more. Flying a proprietary board calibration system that replicates what is normally done on the ground, including the main reference criteria for SI, the truth can achieve uncertainty close to 0.3%.
This increased accuracy can be used not only to provide climate-quality hyperspectral data for many applications, but also to upgrade and harmonize the rest of the world’s space assets. This is achieved by having a unique orbit that allows the truth to observe the same target as other satellites, as well as in many places on Earth. Thus, by looking at the same view simultaneously, the observation of truth can be compared with observations from other satellites, and with discernable and modified differences.
The truth is that it ensures that bias is well understood, allowing sensor data to be harmonized and interoperable, and in many cases, with much higher accuracy than before, it promotes improvements in data products, and often increases the usefulness and opportunity of new applications. The results will be a observation system for future climate responses, allowing commercial satellites to be harmonized and integrated into the mainstream, leading to not only improvements in science but also commercial opportunities for new services.
Can you explain in detail about NPL’s involvement in missions?
The mission was conceived myself about 25 years ago and I am the mission’s chief investigator. It also leads an ESA-funded consortium of international scientists to conduct research into science and sensitivity related to mission design.
NPL is also part of an industrial consortium that supports calibration and engineering designs such as Airbus for calibration and performance-related activities, and will perform final calibration of the mission before it is finally launched in collaboration with RAL Space. Additionally, NPL supports the development of ground segments and how data from missions is quality control and certified.
The NPL team is also developing algorithms to support simulations of mission performance construction. These form part of the mission’s data processing system when it is launched. This latter step is not unique, but it is the first time that such transparency and rigor has been applied to uncertainty assessments of satellite missions. Calibrating other sensors is an important mission objective, so NPL is also developing algorithms and tools to implement this process.
Can you provide a detailed explanation of the outcomes of the mission development process and provide an overview of the next steps and the estimated timeline for further development?
The mission is ready to go through the so-called Preliminary Design Review (PDR) and completed phase B2 following several small updates next month, with the pageload design being completed and fully prototyped and built into space-ready hardware.
So far, all aspects of the mission have been subjected to detailed design and reviews, from satellite platforms, compatibility with potential satellite launchers, how data reaches the ground, how it is processed, how it is delivered to users, and payloads. For the truth, payloads and means of achieving unprecedented uncertainty have been a dominant challenge in recent years. There have been some iterations, but it shows that current designs, and in some cases, prototype hardware can meet the stringent objectives of the mission.
In the future, detailed designs of the ground segments will begin to be realized, and further improvements to the payload will be made.
The mission, like all ESA projects, will be subject to a funding review at the ESA Minister in November, and funding from ESA members will be called to ensure the future of this highly innovative world first mission, led by the UK and scheduled to commence in 2031/32.
This mission can be considered the world’s first measurement laboratory in space, providing gold standard references to optical EO sensors around the world, embedding trust in future interoperable global Earth observation systems.
This article will also be featured in the 23rd edition of Quarterly Publication.
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