Climate Absolute Radiance and Refractivity Observatory

Climate Absolute Radiance and Refractivity Observatory
Name	Climate Absolute Radiance and Refractivity Observatory
Mission type	Earth observation
Operator	NASA / NOAA
Manufacturer	L3Harris Technologies
Launch date	2028 (planned)
Launch rocket	Falcon 9
Launch site	Vandenberg Space Force Base
Orbit reference	Sun-synchronous orbit
Orbit regime	Low Earth orbit

Climate Absolute Radiance and Refractivity Observatory is a planned joint satellite mission between NASA and the NOAA. Designed as a climate observatory, its primary goal is to deliver highly accurate, long-term measurements of Earth's climate system. The mission aims to establish a new benchmark for calibrating other satellite sensors and improving the fidelity of climate models.

Overview

The mission concept was developed to address critical gaps in the long-term climate data record, which is essential for detecting subtle but significant trends. It is a cornerstone of the U.S. Climate Absolute Radiance and Refractivity Observatory program, which focuses on obtaining fundamental climate data. The observatory will operate in a Sun-synchronous orbit, providing consistent observational conditions for its sophisticated suite of instruments.

Scientific objectives and design

The core scientific objective is to measure Earth's radiative forcing with unprecedented accuracy, focusing on both reflected solar radiation and emitted thermal radiation. A key innovation is its design to serve as an "in-orbit standard," directly traceable to SI standards, for calibrating other Earth-observing satellites like those in the Joint Polar Satellite System. This approach, championed by scientists at the University of Colorado Boulder and the National Institute of Standards and Technology, aims to reduce measurement uncertainties that currently limit climate projections.

Development and launch

The mission is being developed under NASA's Earth System Science Pathfinder program, with L3Harris Technologies selected as the primary instrument builder. Following a critical design review, the project is progressing toward integration and testing. A launch aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base is currently scheduled for 2028, after which the spacecraft will undergo an extensive on-orbit commissioning phase led by teams at NASA Goddard Space Flight Center.

Instrumentation and measurements

The payload centers on two primary instruments: the Climate Absolute Radiance and Refractivity Observatory and a Global Positioning System radio occultation receiver. The Climate Absolute Radiance and Refractivity Observatory itself is a highly accurate spectrometer that will measure absolute spectral radiance across the infrared, visible, and shortwave infrared bands. The radio occultation instrument, provided by Jet Propulsion Laboratory, will profile atmospheric temperature, pressure, and humidity by measuring the refraction of GPS signals through Earth's atmosphere.

Data products and applications

Primary data products will include top-of-atmosphere radiance and atmospheric refractivity profiles with rigorously quantified uncertainties. These datasets will be used to calibrate sensors on international partners' satellites, such as those operated by the European Space Agency and Japan Aerospace Exploration Agency. Applications include validating and improving key inputs for major climate models like those used by the Intergovernmental Panel on Climate Change and enhancing the data records maintained by institutions like the World Meteorological Organization.

International collaboration and mission status

The mission fosters significant international collaboration, with contributions from the United Kingdom Space Agency and coordination through bodies like the Committee on Earth Observation Satellites. As of 2024, the project is in its implementation phase, with all major subsystems under construction. Upon successful launch and calibration, the observatory is expected to begin its baseline five-year mission, providing a critical new reference for the global climate observing system.

Category:NASA satellites Category:Earth observation satellites Category:Climate change assessment and attribution