On Feb. 8, SpaceX successfully launched PACE, NASA’s latest Earth observation satellite, from SLC-40, Cape Canaveral. At 06:33 UTC, the Falcon 9 rocket lifted off from the pad. Two minutes and twenty seconds later the second stage separated from the booster, which safely landed on LZ-1. Nearly twelve minutes into the flight the upper stage released the PACE spacecraft into a 676-kilometer Sun-synchronous orbit. The liftoff was initially scheduled for Feb. 6, but was then postponed to Wednesday and subsequently to Thursday due to adverse weather conditions.
The first stage used for this flight (B1081) has previously flown three missions: Crew-7, CRS-29, and a Starlink launch.
PACE has finally reached space after a challenging 9-year-old journey. Authorized in 2015, the mission was at risk of cancellation under Donald Trump’s Administration, however, the Congress kept funding the project. PACE also suffered delays with the COVID pandemic and some issues with an onboard instrument. Finally, the spacecraft was fully assembled in June 2023.
Now NASA’s satellite is finally ready to operate for at least 3 years, enhancing our knowledge of global ocean biology and our impact on its fragile system.
“What we’re doing here with PACE is really the search for the microscopic, mostly invisible, universe in the sea, and in the sky, and, in some degrees, on land.”— Jeremy Werdell, Project Scientist for PACE
Exploring the colours of the ocean
PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) is a NASA mission developed to better understand how climate changes and human activities are affecting ocean biodiversity and cloud formation. This is only the latest mission of this type, as PACE will pursue NASA’s 20 years-long record of satellite observations of global ocean biology, aerosol, and clouds, begun with the Coastal Zone Color Scanner, launched in 1978.
The spacecraft, built and managed by the Goddard Space Flight Center, weighs 1,694 kg and is equipped with a single solar panel that generates one kilowatt of power.
The data collected by PACE will be available to the general public and will bring great benefits in many areas. In particular universities, federal agencies, and scientists will be able to leverage the discoveries to enhance weather and climate forecasting capabilities.
The instruments on board
The Ocean Color Instrument (OCI), PACE’s primary sensor, is an advanced optical spectrometer that will measure light properties across the electromagnetic spectrum. OCI, built at Goddard Space Flight Center (GSFC), will be able to analyze from ultraviolet to near-infrared (350-885 nm) with an unprecedented wavelength resolution.
The color of the ocean is influenced by the substances and particles that interact with the sunlight, like chlorophyll, a pigment found in most phytoplankton species. Through detailed monitoring of global phytoplankton distribution and abundance, OCI will help better understand the complex systems that drive the ocean ecology.
The Spectro-Polarimeter for Planetary Exploration (SPEXone) is a multi-angle polarimeter, developed by the Netherlands Institute for Space Research (SRON) and Airbus DS NL. It is designed to accurately measure the intensity, Degree of Linear Polarization (DoLP) of sunlight reflected from Earth’s aerosols present in the atmosphere, such as airborne dust, pollen, smoke, and haze. SPEXone will help to better examine the characterization of those particles. Aerosols suspended in the air directly affect climate through their interaction with solar radiation and indirectly by changing the properties of clouds.
The Hyper-Angula Rainbow Polarimeter (HARP2) is a wide-angle imaging polarimeter designed to measure aerosol particles, clouds, and properties of land and water surfaces. HARP2 will combine data from multiple along-track viewing angles, four spectral bands, and three angles of linear polarization to study the size distribution, amount, and shape of atmospheric particles. HARP2 is built by UMBC’s Earth and Space Institute.