Release of TRACERS Space Vehicle 2 (SV2) from Falcon 9 second stage. Courtesy of
SpaceX livestream The Sun and the Space Environment of the Earth
The Sun plays a vital role in supporting all forms of life on Earth — providing energy and
nutrients and driving circulation in the atmosphere and ocean. Less widely recognized is that
solar activity, including solar flares and coronal mass ejections, can have damaging effects on
our planet and its space environment. Space weather, including geomagnetic storms, is driven
by the interaction of a stream of charged particles from the Sun, known as the solar wind, with
the Earth’s magnetic field and upper atmosphere. The resulting storms can significantly affect
Earth and human society, not only in space but even on the ground.
In 1989, a powerful geomagnetic storm brought down the Hydro-Québec power grid in Canada
for nine hours, leaving residents with no light or heat. In 2022, another geomagnetic storm
increased drag at low altitudes for 40 SpaceX Starlink satellites, preventing them from reaching
orbit and causing them to burn up in Earth’s atmosphere.
Identifying potential drivers of geomagnetic storms before they reach the Earth would improve
predictions of space weather, potentially mitigating societal impacts. Now, a NASA team that
includes UCLA scientists is taking important steps to help us understand better how such
storms arise. Their work focuses on magnetic reconnection — the process in which magnetic
fields suddenly reconfigure and snap, releasing a burst of energy to power energetic particles.
Magnetic reconnection, still not fully understood, is one of the fundamental processes in the
universe and one of the major causes of space weather events that have the potential to
damage technology and infrastructure on Earth.
The NASA TRACERS Mission
NASA recently launched The Tandem Reconnection and Cusp Electrodynamics
Reconnaissance Satellites (TRACERS) mission to gather critical data on magnetic reconnection
through a pair of identical satellites that will orbit the Earth in tandem, moving through the
tenuous gas of charged particles (called a plasma) that fill space. Equipped with instruments to
study the local space plasma and electromagnetic fields modified by magnetic reconnection, the
satellites are designed to allow researchers to observe changes at different locations and times.
The TRACERS mission aims to understand the variability of the reconnection between the
Earth’s magnetosphere and the solar wind. The data from TRACERS could improve predictions
of energetic particle influx into Earth’s magnetosphere—a critical factor in forecasting and
mitigating potential disruptions to power infrastructure and satellite communications. “Complex
scientific missions like this, which have an immediate impact on society, would not be possible
without the combined efforts of our dedicated scientists and the resources and leadership of
government agencies like NASA,” said Dean of Physical Sciences at UCLA, Miguel Garcia-
Garibay.
The UCLA team on the TRACERS mission, led by Dr. Robert Strangeway and Dr. Hao Cao,
designed and built a critical science instrument, the fluxgate magnetometer (MAG), for the
mission. UCLA has been designing, building, and operating fluxgate magnetometers for NASA
space missions since the beginning of the space age.
“This mission represents the next chapter in UCLA’s amazing history of leadership in space
exploration and space magnetometry,” said EPSS department chair Jonathan Aurnou. “I am
extremely proud of all the researchers that played a part in this groundbreaking endeavor.”
Previous space magnetometers from the UCLA MAG lab include those for the Apollo 15 and 16
subsatellites, OGO-5, ISEE-1 & 2, the Pioneer Venus Orbiter (PVO), Polar, FAST, the Galileo
mission to the Jupiter system, the InSight lander to Mars, the Magnetospheric Multiscale (MMS)
mission, the Europa Clipper mission, and the UCLA student-built ELFIN CubeSats.
The TRACERS Fluxgate Magnetometer (MAG)
Fluxgate magnetometers are used to measure the strength and direction of magnetic fields. The
fluxgate magnetometer designed and built by the UCLA MAG Lab for TRACERS will measure
the Earth’s magnetic field in space with extraordinary precision. The researchers anticipate that,
with these highly precise measurements from TRACERS, better predictive models of space
weather events such as geomagnetic storms can be developed.
TRACERS MAG have undergone rigorous testing at UCLA, University of Iowa, and Millennium
Space Systems which built the spacecraft. Dr. Strangeway has been monitoring the
magnetometer data during the commissioning of one of the TRACERS spacecraft. “The data
are of excellent quality, and I look forward to the forefront scientific research these data will
enable” he said.
