Two NASA satellites successfully launched into orbit from California aboard a SpaceX Falcon 9 rocket on Wednesday, marking the beginning of a $170 million mission aimed at unraveling a long-standing mystery in space physics.
The twin spacecraft are part of the TRACERS mission—an acronym for Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites—which is set to study plasma conditions in narrow regions of Earth’s magnetic field known as polar cusps.
Located over the poles, these regions play a significant yet poorly understood role in producing the stunning auroras we see when plasma from the Sun interacts with Earth’s magnetic field.
This same interaction can lead to geomagnetic storms that disrupt GPS navigation, radio communications, and electrical grids. Such storms are often triggered by solar flares or coronal mass ejections that propel blobs of plasma across the Solar System.
When these plasma flows are directed toward Earth, they bring captivating auroras but also pose risks, as seen in an extreme geomagnetic storm last year that degraded GPS signals and incurred more than $500 million in economic losses in the agriculture sector, as some farms had to halt spring planting.
In 2022, increased solar activity also contributed to the loss of 40 SpaceX Starlink satellites, highlighting the importance of understanding the relationship between solar activities and their effects on Earth.
“Understanding our Sun and the space weather it produces is more important to us here on Earth, I think, than most realize,” said Joe Westlake, director of NASA’s heliophysics division.
The launch of the TRACERS satellites faced a 24-hour delay due to a regional power outage that affected air traffic control over the Pacific Ocean near the launch site on California’s Central Coast.
SpaceX canceled the countdown just before liftoff on Tuesday but successfully rescheduled the launch for Wednesday.
The primary goal of TRACERS is to investigate magnetic reconnection—an essential process that occurs when solar wind particles traveling at speeds of up to 1 million mph interact with Earth’s magnetic field.
This interaction breaks and reconnects magnetic field lines, allowing solar wind particles to be propelled across Earth’s magnetosphere at speeds close to the speed of light.
These particles are drawn into the polar cusps and descend towards the upper atmosphere, creating the brilliant auroras and posing risks for geomagnetic storms.
Despite the occurrence of these events above us, scientists have yet to fully understand the complexities involved.
A single spacecraft would only provide intermittent snapshots of conditions over the polar cusps every 90 minutes, potentially missing crucial changes.
This limitation is where TRACERS’ twin spacecraft become vital.
Each spacecraft is equipped with specialized instruments to measure magnetic fields, electric fields, electrons, and ions, enabling scientists to monitor the dynamic processes of magnetic reconnection.
David Miles, principal investigator for the TRACERS mission at the University of Iowa, emphasized the need for dual spacecraft: “You can’t tell if changes are due to the system itself evolving or if the magnetic reconnection process is shifting. Understanding this nuance is critical.”
This tandem approach will help scientists better understand energy transfer from the solar wind to Earth’s system, a phenomenon with broader implications for space weather.
The two TRACERS spacecraft, each comparable in size to a washing machine, will operate at an altitude of 367 miles (590 kilometers).
Over the coming weeks, they will adjust their positions to trail one another by roughly two minutes as they orbit the Earth at nearly five miles per second.
This formation will allow for consecutive sampling of the polar cusps, significantly improving the frequency of data collection from the satellites compared to traditional single spacecraft missions, which would require waiting 90 minutes for the next pass.
Through the TRACERS mission, scientists aim to gather around 3,000 measurements of magnetic reconnections within a year, a statistical sample that could begin to reveal why some space weather events develop differently than others.
John Dorelli, a TRACERS mission scientist at NASA’s Goddard Space Flight Center, indicated the mission’s broader utility: “It will not only provide a global view of reconnection in the magnetosphere but also allow us to statistically analyze how these processes depend on solar wind conditions.”
Craig Kletzing, the principal investigator leading the TRACERS science team until his passing in 2023, noted the mission’s potential to enhance space weather predictions: “Understanding the various circumstances—whether a phenomenon occurs suddenly or in different locations—can help us model and assess the likelihood of specific effects impacting human activities.”
Beyond its immediate goals, the TRACERS mission has implications for a range of astrophysical phenomena, as magnetic reconnection occurs throughout the Universe and is a common factor in solar flares and coronal mass ejections from the Sun.
Several additional payloads also traveled to space alongside the TRACERS satellites.
Among these was a NASA-sponsored mission called PExT, a small technology demonstration satellite equipped with an experimental communications package designed to connect with various networks, including NASA’s Tracking and Data Relay Satellites and commercial satellite systems owned by SES and Viasat.
PExT serves as a prototype for future operational flexibility, allowing NASA satellites to use multiple communication networks, essential for the agency as it plans to transition from government-owned TDRS satellites to commercial data relay services in the 2030s.
Another technology demonstration, Athena EPIC, was also aboard the Falcon 9 rocket.
This mission, led by NASA’s Langley Research Center, utilizes a modular satellite platform developed by NovaWurks, which enables the integration of necessary spacecraft components.
While Athena EPIC carries a single science instrument that measures Earth’s energy radiation—a vital metric for climate research—the mission primarily aims to illustrate the benefits of adaptable satellite design for enhancing future NASA missions.
The payload for Wednesday’s launch also included REAL, a NASA-funded CubeSat focused on investigating the Van Allen radiation belts and the effects of space weather, as well as LIDE, a 5G communications satellite crewed by the European Space Agency.
Additional spacecraft from the Australian firm Skykraft were launched to bolster a constellation of small satellites aimed at improving tracking and voice communication between air traffic controllers and aircraft operating over remote areas of the globe.
image source from：arstechnica
