ERBS

ERBS
Name	ERBS
Mission type	Earth radiation budget research
Operator	NASA
Launch date	October 5, 1984
Launch vehicle	Space Shuttle Challenger
Launch site	Kennedy Space Center
Mission duration	21 years (primary mission)
Deactivated	October 14, 2005
Orbit reference	Geocentric
Orbit regime	Low Earth orbit
Orbit inclination	57.0 degrees
Orbit period	96.4 minutes

ERBS. The Earth Radiation Budget Satellite was a pioneering NASA spacecraft launched as part of the Space Shuttle Challenger mission STS-41-G. Designed for a two-year primary mission, it operated for over two decades, providing critical long-term data on the Earth's energy budget. Its measurements were fundamental to understanding climate change and validating complex climate model predictions.

Overview

The satellite was a key component of NASA's broader Earth Radiation Budget Experiment, which also included instruments on the NOAA-9 and NOAA-10 satellites. Managed by the Goddard Space Flight Center, its primary purpose was to make precise, simultaneous measurements of incoming solar irradiance and outgoing Earth radiation. The data was crucial for detecting subtle changes in the planet's climate system, contributing to foundational reports by the Intergovernmental Panel on Climate Change.

Scientific mission and objectives

The core scientific mission focused on quantifying the components of the Earth radiation budget, essentially measuring how much energy from the Sun is absorbed by the Earth's atmosphere and surface versus how much is reflected or radiated back into space. A primary objective was to monitor stratospheric aerosol concentrations, particularly following major volcanic eruptions like Mount Pinatubo. This data was vital for studying phenomena such as the ozone depletion over Antarctica and improving the accuracy of global circulation model simulations.

Instrumentation and experiments

The spacecraft carried three primary instruments. The Nonscanner instrument package measured the total outgoing radiation from the entire Earth disk. The Scanner instrument provided detailed spectral measurements of reflected solar and emitted thermal radiation across different wavelengths. A critical payload was the Solar Stellar Irradiance Comparison Experiment, which monitored the Sun's output with high precision, creating a benchmark dataset for solar variability studies that informed research into medieval warm period and little ice age climate shifts.

Launch and orbital parameters

ERBS was deployed into a low Earth orbit from the payload bay of the Space Shuttle Challenger during the STS-41-G mission, which also carried astronaut Kathryn D. Sullivan. Its orbit had an inclination of 57.0 degrees and an altitude of approximately 600 kilometers, allowing it to observe a wide range of latitudes. This orbital path was selected to complement the sun-synchronous orbits of the NOAA satellites, ensuring comprehensive global coverage for the Earth Radiation Budget Experiment.

Data and scientific contributions

The satellite's multi-decade dataset was unprecedented, allowing scientists to track decadal trends in the Earth's energy balance. Its observations were instrumental in quantifying the radiative forcing effect of greenhouse gases and aerosols. The long-term solar irradiance record from its instruments became a cornerstone for understanding natural climate drivers, heavily cited in assessments by the Intergovernmental Panel on Climate Change and influencing international agreements like the Kyoto Protocol.

Operational history and status

Far exceeding its design life, the spacecraft provided valuable data until its final failure in 2005, with mission operations officially terminated by NASA in October of that year. It remains in a decaying low Earth orbit. Its enduring legacy is the validation of the theory of global dimming and its role in the first direct observational evidence of the Earth's energy imbalance, a key metric in modern climatology.

Category:NASA satellites Category:Earth observation satellites Category:Spacecraft launched in 1984