| Names | Explorer PUNCH SMEX |
|---|---|
| Mission type | Heliophysics |
| Operator | NASA |
| Website | punch |
| Spacecraft properties | |
| Spacecraft | PUNCH |
| Spacecraft type | Orbiters (4) |
| Bus | Custom bus, with heritage from CYGNSS |
| Manufacturer | Southwest Research Institute (SwRI) |
| Launch mass | 40 kg (each) |
| Start of mission | |
| Launch date | April 2025 (planned) [1] |
| Rocket | Falcon 9 |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Sun-synchronous orbit |
| Altitude | 570 km [2] |
| Instruments | |
| Narrow Field Imager (NFI) - 1 satellite Wide Field Imagers (WFIs) - 3 satellites | |
Explorer program | |
Polarimeter to Unify the Corona and Heliosphere (PUNCH) is a future mission by NASA to study the unexplored region from the middle of the solar corona out to 1 AU from the Sun. PUNCH will consist of a constellation of four microsatellites that through continuous 3D deep-field imaging, will observe the corona and heliosphere as elements of a single, connected system. The four microsatellites were initially scheduled to be launched in October 2023, but they have since been moved to an April 2025 launch in rideshare with SPHEREx. [1]
On 20 June 2019, NASA announced that PUNCH and TRACERS were the winning candidates to become the next missions in the agency's Small Explorer program (SMEX). [3]
PUNCH is led by Craig Edward DeForest at the Southwest Research Institute (SwRI) in Boulder, Colorado. Including launch costs, PUNCH is being funded for no more than US$165 million. [3]
The stated primary objective of PUNCH is "to fully discern the cross-scale physical processes, from microscale turbulence to the evolution of global-scale structures, that unify the solar corona and heliosphere". [4] In other words, the mission aims to understand how the solar corona becomes the solar wind. [5]
The two specific objectives are to understand how coronal structures become the ambient solar wind, and to understand the dynamic evolution of transient structures in the young solar wind. [4] The Principal Investigator, Craig Edward DeForest from Southwest Research Institute (SwRI), thinks that such closer study will also lead to a better understanding of the causes of solar weather events like coronal mass ejections (CMEs), which can damage satellites and disrupt electrical grids and power systems on Earth. [2] [3]
The more we understand what drives space weather and its interaction with the Earth and lunar systems, the more we can mitigate its effects – including safeguarding astronauts and technology crucial to NASA's Artemis program to the Moon. [3]
The mission configuration consists of a constellation of four observatories, each carrying one primary instrument. [6]
The fields of view (FoV) of the 3 WFIs overlap slightly with each other and with the NFI, and the instruments' operation is synchronized. The instruments operate through polarized Thomson-scatter imaging of the transition from corona to heliosphere. [7] PUNCH integrates images from its constellation of small satellites into a global composite after each orbit, covering ~6 orders of magnitude dynamic range. Through a stream of these images, PUNCH achieves 3D feature localization and accurate deep field imaging. [8] The mission builds on Cyclone Global Navigation Satellite System (CYGNSS) experience with smallsat constellations. [9]
SwRI is collaborating with the Naval Research Laboratory (NRL) and the Rutherford Appleton Laboratory in Oxfordshire, England, United Kingdom.
PUNCH, which will operate in low Earth orbit, will work in synergy with NASA's Parker Solar Probe and the ESA's Solar Orbiter. [2] [7]
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV. The composition of the solar wind plasma also includes a mixture of materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei of elements such as C, N, O, Ne, Mg, Si, S, and Fe. There are also rarer traces of some other nuclei and isotopes such as P, Ti, Cr, 54Fe and 56Fe, and 58Ni, 60Ni, and 62Ni. Superimposed with the solar-wind plasma is the interplanetary magnetic field. The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field. The boundary separating the corona from the solar wind is called the Alfvén surface.
Ulysses was a robotic space probe whose primary mission was to orbit the Sun and study it at all latitudes. It was launched in 1990 and made three "fast latitude scans" of the Sun in 1994/1995, 2000/2001, and 2007/2008. In addition, the probe studied several comets. Ulysses was a joint venture of the European Space Agency (ESA) and the United States' National Aeronautics and Space Administration (NASA), under leadership of ESA with participation from Canada's National Research Council. The last day for mission operations on Ulysses was 30 June 2009.
The Solar and Heliospheric Observatory (SOHO) is a European Space Agency (ESA) spacecraft built by a European industrial consortium led by Matra Marconi Space that was launched on a Lockheed Martin Atlas IIAS launch vehicle on 2 December 1995, to study the Sun. It has also discovered over 4,000 comets. It began normal operations in May 1996. It is a joint project between the European Space Agency (ESA) and NASA. SOHO was part of the International Solar Terrestrial Physics Program (ISTP). Originally planned as a two-year mission, SOHO continues to operate after over 25 years in space; the mission has been extended until the end of 2025, subject to review and confirmation by ESA's Science Programme Committee.
Pegasus is an air-launched launch vehicle developed by Orbital Sciences Corporation (OSC) and now built and launched by Northrop Grumman. Pegasus is the world's first privately developed orbital launch vehicle. Capable of carrying small payloads of up to 443 kg (977 lb) into low Earth orbit, Pegasus first flew in 1990 and remains active as of 2021. The vehicle consists of three solid propellant stages and an optional monopropellant fourth stage. Pegasus is released from its carrier aircraft at approximately 12,000 m (39,000 ft), and its first stage has a wing and a tail to provide lift and attitude control while in the atmosphere. Notably, the first stage does not have a thrust vector control (TVC) system.
The heliosphere is the magnetosphere, astrosphere, and outermost atmospheric layer of the Sun. It takes the shape of a vast, bubble-like region of space. In plasma physics terms, it is the cavity formed by the Sun in the surrounding interstellar medium. The "bubble" of the heliosphere is continuously "inflated" by plasma originating from the Sun, known as the solar wind. Outside the heliosphere, this solar plasma gives way to the interstellar plasma permeating the Milky Way. As part of the interplanetary magnetic field, the heliosphere shields the Solar System from significant amounts of cosmic ionizing radiation; uncharged gamma rays are, however, not affected. Its name was likely coined by Alexander J. Dessler, who is credited with the first use of the word in the scientific literature in 1967. The scientific study of the heliosphere is heliophysics, which includes space weather and space climate.
The Solar Orbiter (SO) is a Sun-observing probe developed by the European Space Agency (ESA) with a National Aeronautics and Space Administration (NASA) contribution. Solar Orbiter, designed to obtain detailed measurements of the inner heliosphere and the nascent solar wind, will also perform close observations of the polar regions of the Sun which is difficult to do from Earth. These observations are important in investigating how the Sun creates and controls its heliosphere.
Solar physics is the branch of astrophysics that specializes in the study of the Sun. It deals with detailed measurements that are possible only for our closest star. It intersects with many disciplines of pure physics, astrophysics, and computer science, including fluid dynamics, plasma physics including magnetohydrodynamics, seismology, particle physics, atomic physics, nuclear physics, stellar evolution, space physics, spectroscopy, radiative transfer, applied optics, signal processing, computer vision, computational physics, stellar physics and solar astronomy.
STEREO is a solar observation mission. Two nearly identical spacecraft were launched in 2006 into orbits around the Sun that cause them to respectively pull farther ahead of and fall gradually behind the Earth. This enabled stereoscopic imaging of the Sun and solar phenomena, such as coronal mass ejections.
The Solar Dynamics Observatory (SDO) is a NASA mission which has been observing the Sun since 2010. Launched on 11 February 2010, the observatory is part of the Living With a Star (LWS) program.
Interstellar Boundary Explorer is a NASA satellite in Earth orbit that uses energetic neutral atoms (ENAs) to image the interaction region between the Solar System and interstellar space. The mission is part of NASA's Small Explorer program and was launched with a Pegasus-XL launch vehicle on 19 October 2008.
The Max Planck Institute for Solar System Research is a research institute in astronomy and astrophysics located in Göttingen, Germany, where it relocated in February 2014 from the nearby village of Lindau. The exploration of the Solar System is the central theme for research done at this institute.
The Solar Sentinels was a series of proposed space missions to the Sun. Solar Sentinels was proposed in 2006 in conjunction with other Sun missions, and another simpler proposal was submitted in 2008.
The Parker Solar Probe is a NASA space probe launched in 2018 with the mission of making observations of the outer corona of the Sun. It will approach to within 9.86 solar radii from the center of the Sun, and by 2025 will travel, at closest approach, as fast as 690,000 km/h (430,000 mph), or 0.064% the speed of light. It is the fastest object ever built by humans.
Energetic Neutral Atom (ENA) imaging, often described as "seeing with atoms", is a technology used to create global images of otherwise invisible phenomena in the magnetospheres of planets and throughout the heliosphere.
Interface Region Imaging Spectrograph (IRIS), also called Explorer 94 and SMEX-12, is a NASA solar observation satellite. The mission was funded through the Small Explorer program to investigate the physical conditions of the solar limb, particularly the interface region made up of the chromosphere and transition region. The spacecraft consists of a satellite bus and spectrometer built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), and a telescope provided by the Smithsonian Astrophysical Observatory (SAO). IRIS is operated by LMSAL and NASA's Ames Research Center.
The Heliophysics Science Division of the Goddard Space Flight Center (NASA) conducts research on the Sun, its extended Solar System environment, and interactions of Earth, other planets, small bodies, and interstellar gas with the heliosphere. Division research also encompasses geospace—Earth's uppermost atmosphere, the ionosphere, and the magnetosphere—and the changing environmental conditions throughout the coupled heliosphere.
The Vigil mission, formerly known as Lagrange, is a Space weather weather mission developed by European Space Agency. The mission will provide the ESA Space Weather Office with instruments able to monitor the Sun, its solar corona and interplanetary medium between the Sun and Earth, to provide early warnings of increased solar activity, to identify and mitigate potential threats to society and ground, airborne and space based infrastructure as well as to allow 4 to 5 days space weather forecasts. To this purpose the Vigil mission will place for the first time a spacecraft at Sun-Earth Lagrange point 5 (L5) from where it would get a 'side' view of the Sun, observing regions of solar activity on the solar surface before they turn and face Earth.
SPHEREx is a future near-infrared space observatory that will perform an all-sky survey to measure the near-infrared spectra of approximately 450 million galaxies. In February 2019, SPHEREx was selected by NASA for its next Medium-Class Explorers mission, beating out two competing mission concepts: Arcus and FINESSE. As of August 2022, SPHEREx is targeted to launch no earlier than April 2025 on a Falcon 9 launch vehicle from Vandenberg Space Force Base. The principal investigator is James Bock at California Institute of Technology (Caltech) in Pasadena, California.
Space Weather Follow On-Lagrange 1 (SWFO-L1) is a future spacecraft mission planned to monitor signs of solar storms, which may pose harm to Earth's telecommunication network. The spacecraft will be operated by the National Oceanic and Atmospheric Administration (NOAA), with launch scheduled for February 2025. It is planned to be placed at the Sun–Earth L1 Lagrange point, a location between the Earth and the Sun. This will allow SWFO-L1 to continuously watch the solar wind and energetic particles heading for Earth. SWFO-L1 is an ESPA Class Spacecraft, sized for launch on an Evolved Expendable Launch Vehicle Secondary Payload Adapter (ESPA) Grande ring in addition to the rocket's primary payload. The spacecraft's Solar Wind Instrument Suite (SWIS) which includes three instruments will monitor solar wind, and the Compact Coronagraph (CCOR) will monitor the Sun's surroundings to image coronal mass ejection (CME). A CME is a large outburst of plasma sent from the Sun towards interplanetary space.
Daniel B. Seaton is an American solar physicist based at the Southwest Research Institute (SwRI) in Boulder, Colorado. He is particularly known for his work on producing and interpreting images of the solar corona, using both visible light and extreme ultraviolet.
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