A Trio of Spacecraft Embarks on a Journey to the Edge of the Heliosphere
In a significant milestone for space exploration, three spacecraft have successfully launched into deep space aboard a Falcon 9 rocket from NASA’s Kennedy Space Center in Florida. The trio, consisting of the Interstellar Mapping and Acceleration Probe (IMAP), the Carruthers Geocorona Observatory, and the Space Weather Follow On-L1 (SWFO-L1) satellite, is bound for the L1 Lagrange point, a gravitational balance point roughly 900,000 miles from Earth toward the Sun.
The combined weight of these three spacecraft is approximately $2.5 billion, with IMAP being the largest and most complex mission at nearly $800 million. The missions will spend at least two years conducting scientific observations in deep space, providing valuable insights into the heliosphere, the solar wind, and the interstellar medium.
The primary mission launched on Wednesday is called the Interstellar Mapping and Acceleration Probe (IMAP). The spin-stabilized IMAP spacecraft is shaped like a donut, with a diameter of about 8 feet (2.4 meters) and 10 science instruments looking inward toward the Sun and outward toward the edge of the heliosphere.
At the edge of the heliosphere, the solar wind runs up against the interstellar medium, the gas, dust, and radiation in the space between the stars. This boundary remains a poorly understood frontier in space science, but it’s essential because the heliosphere protects the Solar System from damaging galactic cosmic rays.
"IMAP is a mission of firsts," said Nicky Fox, associate administrator of NASA’s science mission directorate. "It’ll be the first spacecraft dedicated to mapping the heliosphere’s outer boundary, a key piece in the heliophysics puzzle about the Sun’s influence on our Solar System."
During its two-year mission, IMAP will conduct detailed observations of the solar wind and interstellar medium, providing unprecedented insights into the structure and dynamics of the heliosphere. The spacecraft’s suite of instruments is designed to detect a wide range of phenomena, from energetic neutral atoms to magnetic field fluctuations.
The second mission, the Carruthers Geocorona Observatory, is a smaller but equally significant endeavor. This $97 million mission carries two co-aligned ultraviolet imagers designed for simultaneous observations of Earth’s exosphere, a tenuous cloud of hydrogen gas that fades into the airless void of outer space about halfway to the Moon.
The Carruthers observatory was built by BAE Systems, with instruments provided by the University of California Berkeley’s Space Sciences Lab. The mission is named after George Carruthers, an engineer and solar physicist who developed an ultraviolet camera placed on the Moon by the Apollo 16 astronauts in 1972.
"We actually don’t know exactly how big it [the exosphere] is," said Lara Waldrop, the mission’s principal investigator from the University of Illinois Urbana-Champaign. "We don’t know whether it’s spherical or oval, how much it changes over time or even the density of its constituent hydrogen atoms."
The third and final spacecraft on board the Falcon 9 rocket is the Space Weather Follow On-L1 (SWFO-L1) satellite. This $692 million mission serves as an "early warning beacon" for the potentially devastating effects of geomagnetic storms, said Irene Parker, deputy assistant administrator for systems at NOAA’s National Environmental Satellite, Data, and Information Service.
NOAA’s previous satellites peer down at Earth from low-Earth orbit or geosynchronous orbit, gathering data for numerical weather models and tracking the real-time movement of hurricanes and severe storms. Until now, NOAA has relied upon a hodgepodge of research satellites to monitor the solar wind upstream from Earth.
SWFO-L1 is designed from the start for real-time, around-the-clock solar wind observations. Once on station around the L1 Lagrange point, the satellite will be renamed SOLAR-1 before NOAA declares it operational in mid-2026.
The combined presence of IMAP, Carruthers, and SWFO-L1 at the L1 Lagrange point represents a significant milestone for space exploration. By studying the heliosphere, solar wind, and interstellar medium together, scientists will gain a deeper understanding of our Solar System’s place within the larger universe.
Mission Objectives
IMAP Mission Objectives:
- Map the heliosphere’s outer boundary
- Study the interaction between the solar wind and the interstellar medium
- Investigate the sources of high-energy particles in the heliosphere
Carruthers Geocorona Observatory Mission Objectives:
- Observe Earth’s exosphere using ultraviolet imagers
- Determine the size, shape, and density of the exosphere
- Study the effects of solar wind on the exosphere
SWFO-L1 (SOLAR-1) Mission Objectives:
- Monitor the solar wind in real-time
- Detect geomagnetic storms before they impact Earth
- Provide early warnings for space weather events
Launch and Deployment
The three spacecraft launched on a Falcon 9 rocket from NASA’s Kennedy Space Center in Florida. The rocket lifted off at 12:50 PM EST, carrying the spacecraft to the L1 Lagrange point.
Once on station around the L1 Lagrange point, the spacecraft will begin their respective missions. IMAP will conduct detailed observations of the solar wind and interstellar medium, while Carruthers will observe Earth’s exosphere using ultraviolet imagers. SWFO-L1 will monitor the solar wind in real-time, providing early warnings for space weather events.
Significance
The launch of IMAP, Carruthers, and SWFO-L1 represents a significant milestone for space exploration. By studying the heliosphere, solar wind, and interstellar medium together, scientists will gain a deeper understanding of our Solar System’s place within the larger universe.
"This is the ultimate cosmic carpool," said Joe Westlake, director of NASA’s heliophysics division. "These three missions heading out to the Sun-Earth L1 point riding along together provide immense value for the American taxpayer."
"It’s like a bus," Fox said. "You wait for one and then three come at the same time.