This artist’s concept shows the Wide Field Infrared Surveyor (WISE) spacecraft orbiting the Earth. The NEOWISE mission will find and characterize asteroids.
Credit: NASA/JPL-California Institute of Technology

Infrared space telescopes searching for asteroids and comets have collected vast amounts of observations, but are now at the mercy of the sun, which is accelerating their demise.

NASA’s Neowise It’s been a busy 10 years. Since its resumed mission began on December 13, 2013, the space telescope has discovered once-in-a-lifetime comets, observed more than 3,000 near-Earth objects, strengthened international planetary defense strategies, and It has helped other NASA missions rendezvous with distant space. asteroid. This is just a partial list of achievements.

But all good things must come to an end. Solar activity is pushing NEOWISE (short for Near-Earth Object Wide-field Infrared Survey Explorer) out of orbit. By early 2025, the spacecraft is expected to have fallen far enough into Earth’s atmosphere that it will become unusable. Eventually it will re-enter the atmosphere and burn up completely.

Approximately every 11 years, the Sun goes through a cycle of increasing activity, peaking during a period called solar maximum. Explosive events such as solar flares and coronal mass ejections will become more frequent, heating the Earth’s atmosphere and causing it to expand. Atmospheric gases increase the drag on satellites as they orbit the Earth, slowing them down. Now, as the Sun approaches its next maximum, NEOWISE will no longer be able to maintain its orbit above the atmosphere.

Comet C/2020 F3 NEOWISE is a composite of several heat-sensitive infrared images taken by NASA’s Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission on March 27, 2020. Appears as a blurry red dot.
Credit: NASA/JPL-California Institute of Technology

“The mission has been planning for this day for a long time. After several years of lull, the sun is waking up again,” said NEOWISE co-principal investigator and researcher at the California Institute of Technology in Pasadena, California. said Joseph Masiello, a scientist with the organization IPAC. “With us at the mercy of solar activity and no means of staying in orbit, NEOWISE is now slowly spiraling back to Earth.”

wise beginnings

The past decade has meant a second life for the spacecraft. Managed by NASA’s Jet Propulsion Laboratory in Southern California, NEOWISE is part of another mission launched in 2009, the Wide-Field Infrared Surveyor (wise). Data from WISE and NEOWISE is used to study distant galaxies, cold stars, and explosions. white dwarf Stars, gas-emitting comets, near-Earth asteroids, etc.

In 2010, WISE achieved its scientific goal of conducting an all-sky infrared survey with far greater sensitivity than previous surveys. WISE mission also discovered tens of millions of actively feeding supermassive black holes across the sky.through disc detective In this project, citizen scientists used WISE data to find circumstellar disks, which are clouds of gas, dust, and debris that rotate around stars.

Infrared wavelengths, which are invisible to the naked eye, are emitted by warm objects. To ensure that the heat generated by WISE itself does not interfere with observations in infrared wavelengths, the spacecraft relied on cryogenic coolant. NASA put the spacecraft into hibernation in February 2011 after it ran out of coolant and WISE mapped the sky twice.

Without the coolant, space telescopes could no longer observe the coldest objects in the universe, but they could still see near-Earth asteroids and comets heated by the sun. So NASA restarted the spacecraft in 2013 with a more specialized role in mind. The goal is to support planetary defense efforts by investigating and studying objects that may wander into Earth’s orbit and pose a potential collision hazard.

In addition to relying on missions to explore these objects, astronomers use that data to understand the object’s size, albedo, or how much sunlight its surface reflects, and the composition of its structure. You can also collect clues about the minerals and rocks you find.

“NEOWISE demonstrates the importance of deploying infrared space exploration telescopes as part of NASA’s planetary defense strategy while also monitoring objects in our solar system and beyond,” said lead researcher Amy, from the University of Arizona in Tucson. Mainzer said. .

Mainzer also leads NASA’s future plans. NEO surveyor, built on the NEOWISE tradition. The next generation of infrared space telescopes will search for celestial objects close to the Earth, such as dark asteroids and comets that do not reflect much visible light, or objects that approach the Earth from the direction of the sun. Sun. The launch is scheduled for 2027. JPL-Managed missions will also explore objects known as Earth Trojans – asteroids that lead or follow our planet’s orbit. The first one is wise discovery In 2011.

Comet NEOWISE and beyond

Since becoming NEOWISE, the mission has scanned the entire sky more than 20 times and made 1.45 million infrared measurements on more than 44,000 Solar System objects. This includes over 3,000 near-Earth objects, 215 of which were discovered by his NEOWISE. Data from the mission helped refine the orbits of these objects, while also measuring their sizes.

Its strength is in revealing the characteristics of asteroids near the Earth. In 2021, NEOWISE became a key component of an international planetary defense exercise focused on the dangerous asteroid Apophis.

The mission also discovered 25 comets, including long-period comet C/2020 F3 (NEOWISE). The comet was a dazzling object visible in the Northern Hemisphere for several weeks in 2020, making it the first comet to be visible to the naked eye since 2007, when Comet McNaught was primarily visible in the Southern Hemisphere.

Future researchers will use WISE in 2010, long after observations were made to characterize the asteroid Dinkinesh, in support of NASA’s Lucy mission before the October 2023 encounter. Just as we used the data, we will continue to rely on the vast archive of NEOWISE observations to make new discoveries.

“This is a bittersweet moment. We are sad to see this pioneering mission come to an end, but we know there are even more treasures hidden in the survey data,” Masiello said. “NEOWISE has a vast archive that covers a very long period of time and will inevitably advance the science of the infrared universe long after the spacecraft leaves.”

Mission details
NEOWISE and NEO Surveyor are part of NASA’s Planetary Defense Coordination Office (PDCO) at NASA Headquarters in Washington. The NASA Authorization Act of 2005 directs NASA to discover and characterize at least 90% of near-Earth objects larger than 140 meters (460 feet) in diameter that come within 30 million miles (48 million kilometers) of Earth’s orbit. did. An object of this size could cause significant damage to the region, and it would be even worse if it crashed into Earth.
JPL manages and operates PDCO’s NEOWISE mission within the Science Mission Directorate. The Astrodynamics Laboratory in Logan, Utah, built the scientific instrument. Ball Aerospace & Technologies of Boulder, Colorado, built the spacecraft. Scientific data processing will take place at IPAC at the California Institute of Technology. Caltech manages JPL for NASA.

Source: scitechdaily.com