Editor’s note: An earlier version of this post misstated the number of IMAP instruments and details of the mission’s science goals. The below text has been updated.
An instrument that will collect and analyze ions — charged particles — has been integrated into NASA’s IMAP (Interstellar Mapping and Acceleration Probe) at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. This instrument, known as the Solar Wind and Pick Up Ion (SWAPI) instrument, will help scientists understand how ions behave in the protective bubble surrounding the solar system called the heliosphere, helping provide situational awareness of the very nature of space that our satellites travel through.
The Solar Wind and Pick-Up Ion (SWAPI) instrument completed flight model in the Space Physics Lab at Princeton University before shipping to Johns Hopkins APL for integration onto the IMAP spacecraft. Shown is the pickup ion sector. Credit: NASA/Princeton
Using SWAPI and nine other instrument suites, IMAP will sample, analyze, and map particles streaming towards Earth from the edges of interstellar space to help researchers better understand the boundary of the heliosphere. The mission will also help researchers learn more about the solar wind and cosmic rays in the heliosphere, which can affect human explorers in space and can harm technological systems, and likely play a role in the presence of life itself in the universe. The mission is slated to launch in 2025.
The ions SWAPI will capture include ones from the solar wind — the constant stream of particles from the Sun — as well as one called interstellar pick-up ions, which originate outside the solar system and have been energized by radiation or other particles from the Sun. Both types of ions will allow scientists to study how these charged particles interact at the outer edge of the heliosphere from afar.
The instrument’s data will also provide temperature, density, and speed information about the local ion conditions around IMAP. This information will enable space weather to be measured in real-time. Furthermore, the data from SWAPI will increase our understanding of how changes in Sun’s behavior affect the solar wind.
The persistence and creativity of the SWAPI team allowed them to successfully iterate the design of the instrument to accommodate the technical challenges posed by the necessary high voltage operations. With SWAPI’s integration, IMAP is now equipped with seven out of its total 10 instrument suites.
Princeton student team members with the Solar Wind and Pick-up Ion (SWAPI) instrument in the Space Physics Lab at Princeton preparing the flight model for shipment to Johns Hopkins APL for integration onto the IMAP spacecraft. Credit: NASA/Princeton
The SWAPI instrument was designed and assembled by Princeton University. Princeton University professor David J. McComas leads the IMAP mission with an international team of 25 partner institutions. The Johns Hopkins Applied Physics Laboratory builds the spacecraft and operates the mission. IMAP is the fifth mission in NASA’s Solar Terrestrial Probes program portfolio. The Explorers and Heliophysics Project Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the Solar Terrestrial Program for the agency’s Heliophysics Division of NASA’s Science Mission Directorate.
Scientists and engineers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, are poised to deliver the High-energy Ion Telescope (HIT) instrument. HIT was shipped from Goddard to the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. A group of engineers at APL have now begun the process of installing HIT onto NASA’s Interstellar Mapping and Acceleration Probe (IMAP) spacecraft.
HIT instrument installed in the vacuum chamber at the Tandem Van de Graaff accelerator facility at Brookhaven National Laboratory in Upton, New York. Credit: Brookhaven National Laboratory.
A YouTube livestream shows the cleanroom where the spacecraft will be built and tested over the next year on Princeton University’s IMAP mission website. Viewers can watch the continuous stream to see exactly how the IMAP hardware develops from a bare-bones structure to the complex, fully operational spacecraft.
HIT is the fourth of 10 IMAP instruments to arrive at APL. Over the two-year-long mission, HIT will measure high-energy solar energetic particles expelled from the Sun in the highest-energy processes in our solar system. These solar particles can produce the beautiful aurora, or northern and southern lights, but are also hazardous, posing risks to the health and safety of astronauts as well as presenting a danger to space- and ground-based assets and infrastructure. Understanding the acceleration and transport of this high-energy radiation will help us better understand our Sun and the local space weather to which these particles play a critical role.
Front-view of HIT in vacuum chamber after completing a thermal vacuum cycling test. Credit: NASA/Michael Choi.
“Solar energetic particles have been studied since the start of the space age, yet we still don’t understand their origin well enough to predict when they will be a danger,” said Eric Christian, HIT instrument lead and deputy principal investigator of the IMAP mission at NASA Goddard. “HIT, combined with other instruments on IMAP, will provide an important piece of the puzzle.”
IMAP, which is led by Princeton University, is slated to launch in 2025 and will journey roughly one million miles to a point in space between Earth and the Sun called Lagrange Point 1. During the mission, HIT will measure energetic ions and electrons to help us learn more about the processes that can accelerate these particles to such high energies.
Building on Heritage
HIT builds upon techniques that are decades old but modernizes them with state-of-the-art instrumentation and clever detector design. When charged particles pass through HIT, they deposit some of their energy in layers of detector material until they finally come to rest. By looking at the energy deposited in the different layers through which the particle passed and comparing it with the energy deposited in the stopping layer, HIT can determine the type (proton, electron, or different ions) and energy of the particle.
The arrangement of 10 apertures, or openings, on HIT and the spin of the IMAP spacecraft will allow HIT to measure particles from all directions and study the energetic particles patterns when striking the instrument. HIT also measures energetic electrons, which arrive at Earth quickly and can give us an early warning to upcoming space weather events.
The Work of a Team
HIT would not be possible without its dedicated and diverse group of scientists, engineers, and technicians at NASA Goddard and the California Institute of Technology. The HIT team includes many early career scientists and engineers who got the exciting opportunity to take on leadership roles and rose to the challenge. For many, this will be the first time they will have the unique opportunity to work on something going to space.
“I am so grateful to have the opportunity to play an integral role in such an exciting mission,” said Grant Mitchell, a member of the HIT science team at NASA Goddard. “The chance to learn from world-class scientists and engineers both at Goddard and throughout the IMAP team has been instrumental in preparing me to lead my own missions one day.”
Princeton University professor David J. McComas leads the mission with an international team of 25 partner institutions. The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, builds the spacecraft and operates the mission. IMAP is the fifth mission in NASA’s Solar Terrestrial Probes (STP) Program portfolio. The Explorers and Heliophysics Project Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the STP Program for the Heliophysics Division of NASA’s Science Mission Directorate.
The Interstellar Mapping and Acceleration Probe (IMAP) has successfully completed Key Decision Point D (KDP-D). This milestone allows the mission to move from development and design to the assembly, testing, and integration phase. IMAP’s planned launch date, which was no earlier than February 2025, was also reevaluated during the KDP-D and was moved to a target launch window from late April to late May 2025 to ensure that the project team has adequate resources to address risks and technical complexities during system integration and testing.
IMAP will study the protective magnetic bubble that surrounds our solar system, called the heliosphere. Credits: NASA/Princeton/Johns Hopkins APL/Josh Diaz
IMAP will function as a modern-day cartographer and will help us understand what happens when the solar wind (a constant stream of particles from the Sun) collides with materials from interstellar space. This will help researchers map the boundary of the heliosphere, the magnetic bubble created by the solar wind, and better understand how this magnetic bubble protects Earth from large amounts of harmful cosmic radiation. IMAP will be positioned about one million miles from Earth, and its instruments will collect and study the particles that make it through the heliosphere.
Principal investigator and Princeton University professor David McComas leads the IMAP mission, which has an international team of more than 20 partner institutions. Johns Hopkins Applied Physics Laboratory (APL) is managing the development phase, is building the spacecraft, and will operate the mission. IMAP is the fifth mission in NASA’s Solar Terrestrial Probes (STP) Program portfolio. The Explorers and Heliophysics Projects Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the STP Program for the agency’s Heliophysics Division of NASA’s Science Mission Directorate.
The public can watch the spacecraft come together in real time via a live feed from APL’s clean room, which is now available to watch at any time on the IMAP mission website. Viewers can watch the continuous stream to see exactly how IMAP develops from a bare-bones structure to a complex, fully operational spacecraft.
The mechanical team is preparing to install the Medium Gain Antenna on the IMAP spacecraft. Credits: NASA/Johns Hopkins APL/Princeton/Ed Whitman
