NASA’s NEOWISE Asteroid Hunter: A Decade of Near-Earth Object Discoveries and the Future of Planetary Defense

NASA’s NEOWISE mission, originally launched as the Wide-field Infrared Survey Explorer (WISE) in 2009, has recently concluded after an illustrious career spanning nearly 15 years. The spacecraft, which orbited Earth, was designed to scan the sky for infrared signals, initially focusing on faraway celestial objects. However, its mission evolved significantly over time, making it one of NASA’s most valuable tools for detecting near-Earth objects (NEOs), including asteroids and comets that could potentially threaten our planet. The final image captured by NEOWISE, showing part of the Fornax constellation, marked the end of a mission that greatly exceeded its original goals.

The NEOWISE mission was an extension of the WISE mission, which ran out of coolant in 2010 after completing a full infrared scan of the sky. Recognizing the spacecraft’s potential for studying closer objects, NASA repurposed it to focus on asteroid detection. Rebranded as NEOWISE, the mission resumed in 2013 and quickly began making significant discoveries. One of its early achievements was the detection of the asteroid Holda, setting the stage for many more findings to come. Over its operational life, NEOWISE made over 3,000 discoveries, including 215 near-Earth objects and 25 comets.

NEOWISE’s ability to detect asteroids and comets was not just a scientific curiosity; it played a crucial role in planetary defense. By identifying and tracking potentially hazardous objects, the mission contributed to our understanding of the near-Earth environment and helped lay the groundwork for future planetary defense initiatives. The data collected by NEOWISE has been invaluable for scientists and engineers, providing insights that will be used for years to come. Dr. Amy Mainzer, an astronomer at UCLA and the principal investigator for NEOWISE, expressed gratitude for the opportunity to work on what she called ‘the little space telescope that could.’

Despite its many successes, NEOWISE faced challenges that ultimately led to its decommissioning. Increased solar activity caused the spacecraft’s orbit to degrade, making it too low for useful scientific operations. Without a propulsion system to boost its orbit, NEOWISE was expected to safely burn up in Earth’s atmosphere by late 2024. The final command to shut off its transmitter was sent on August 8, 2024, marking the official end of the mission. However, the legacy of NEOWISE will live on through the data it collected and the scientific papers that will continue to be published based on its findings.

One of the most significant contributions of NEOWISE was its role in the discovery and observation of Comet NEOWISE in 2020. This bright comet captured the public’s imagination and brought attention to the importance of monitoring near-Earth objects. The mission also observed a space rock named Dinkinesh, which provided useful data for a recent NASA flyby. These discoveries have not only expanded our knowledge of the solar system but also highlighted the need for continued vigilance in tracking objects that could pose a threat to Earth.

As NEOWISE’s mission came to an end, attention turned to its successor, the Near-Earth Object Surveyor (NEO Surveyor). Set to launch no earlier than 2027, NEO Surveyor will build on the achievements of NEOWISE with enhanced capabilities for detecting difficult-to-find objects. The new spacecraft will complete a full scan of the sky every two weeks and will be equipped with a purpose-built solar shade to hunt for asteroids near the glare of the sun. This next-generation planetary defender aims to discover 90% of near-Earth objects larger than 140 meters in diameter, a task that Congress has mandated NASA to achieve.

The transition from NEOWISE to NEO Surveyor represents a new era in asteroid detection and planetary defense. Dr. Mainzer and her team at NASA’s Jet Propulsion Laboratory (JPL) are already hard at work preparing for the launch of NEO Surveyor. The new mission will greatly expand our understanding of objects in Earth’s neighborhood and provide critical data for protecting our planet. In the meantime, ground-based telescopes and international partnerships will continue to play a vital role in monitoring near-Earth objects.

NEOWISE’s impact on planetary defense cannot be overstated. The mission’s data has informed the development of new technologies and strategies for detecting and tracking potentially hazardous objects. Laurie Leshin, director of NASA’s Jet Propulsion Laboratory, praised NEOWISE for expanding our knowledge of asteroids and comets, and for its contributions to the next generation of planetary defense efforts. The mission’s achievements were celebrated by past and present team members, as well as officials from NASA’s headquarters in Washington.

Despite the end of NEOWISE, the work of analyzing its data continues. Dr. Mainzer and her team plan to release the final data set in the fall and publish several scientific papers based on their findings. The data collected by NEOWISE over its decade-long mission will provide valuable insights for years to come. This ongoing research will help scientists better understand the composition, behavior, and potential threats posed by near-Earth objects.

The story of NEOWISE is a testament to the ingenuity and perseverance of the scientists and engineers who worked on the mission. From its humble beginnings as WISE to its transformation into a critical tool for planetary defense, NEOWISE has left an indelible mark on our understanding of the cosmos. As we look to the future, the lessons learned from NEOWISE will guide the development of new missions and technologies aimed at protecting our planet from potential threats.

In conclusion, the NEOWISE mission has been a remarkable journey of discovery and innovation. Its contributions to our understanding of near-Earth objects and planetary defense are invaluable. While the spacecraft may no longer be operational, its legacy will live on through the data it collected and the scientific advancements it inspired. As we prepare for the launch of NEO Surveyor, we can look back on NEOWISE with pride and gratitude for all that it has accomplished. The mission has set the stage for a new era of exploration and protection, ensuring that we remain vigilant in safeguarding our planet from potential hazards in the cosmos.

The final image captured by NEOWISE, showing part of the Fornax constellation, serves as a fitting tribute to a mission that has done so much to advance our understanding of the universe. As we bid farewell to NEOWISE, we look forward to the exciting discoveries and innovations that lie ahead with the launch of NEO Surveyor. The future of planetary defense is bright, thanks in large part to the pioneering work of NEOWISE and the dedicated team of scientists and engineers who made it all possible.