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Navigating the Future: NASA’s Groundbreaking Space-Based Quantum Sensor for Gravity Measurement

In a pioneering effort to explore gravitational dynamics, researchers from NASA’s Jet Propulsion Laboratory (JPL) in Southern California, in collaboration with private industry and academic institutions, are developing a revolutionary space-based quantum sensor capable of measuring gravity. This initiative, backed by NASA’s Earth Science Technology Office (ESTO), represents a significant advancement in quantum sensing, destined to enhance our understanding of critical Earth resources from underground water supplies to mineral reserves.

The gravitational field of the Earth is not static; it fluctuates daily as geological processes shift mass around the planet. These changes are subtle and typically imperceptible in daily life, yet advanced instruments known as gravity gradiometers can detect and map these variances, linking them to underlying geological features such as aquifers and mineral deposits. The insights gained from gravity mapping are invaluable for navigation, resource management, and even national security concerns.

“With atomic measurements, we can ascertain the mass of significant structures, like the Himalayas,” remarked Jason Hyon, chief technologist for Earth Science at JPL and director of the Quantum Space Innovation Center. He and his associates articulated the foundational concepts for their Quantum Gravity Gradiometer Pathfinder (QGGPf) in a recent publication in EPJ Quantum Technology.

The functionality of gravity gradiometers hinges on assessing how quickly objects fall in differing locations. The variation in acceleration of falling objects, known as test masses, reveals differences in gravitational strength—areas with greater mass exert stronger gravitational pull, causing objects to fall faster.

The QGGPf will utilize two ultra-cold rubidium atom clouds as its test masses. At temperatures approaching absolute zero, these atoms exhibit wave-like characteristics. The instrument will measure the differential acceleration of these atomic wave functions to identify gravitational anomalies.

Employing ultra-cold atoms as test masses ensures that orbital gravity measurements maintain high precision over extended periods, as indicated by Sheng-wey Chiow, a physicist at JPL. “Using atoms allows us to standardize every measurement, minimizing sensitivity to environmental factors,” he explained.

Additionally, using atoms permits the development of a compact, efficient instrument for space. The QGGPf is designed to occupy approximately 0.3 cubic yards (0.25 cubic meters) and weigh around 275 pounds (125 kilograms), making it significantly lighter and smaller compared to conventional space-based gravitational instruments.

Quantum sensors further boast enhanced sensitivity; estimates suggest that a science-grade quantum gravity gradiometer could be up to ten times more sensitive at gravity measurement than traditional methods.

The primary objective of this technology validation mission, set to launch in the latter part of the decade, is to evaluate a range of novel technologies designed for manipulating atomic-scale interactions among light and matter.

“This will be the first experience of flying such an instrument,” said Ben Stray, a postdoctoral researcher at JPL. “Conducting this flight will help us understand its operational capabilities, advancing not only the quantum gravity gradiometer but also quantum technology as a whole.”

This project highlights substantial collaboration between NASA and small businesses. JPL’s team is working in partnership with AOSense and Infleqtion to enhance the sensor head technology, while NASA’s Goddard Space Flight Center, located in Greenbelt, Maryland, is collaborating with Vector Atomic to improve the laser optical systems.

Ultimately, the innovations fostered during this pioneering mission could significantly boost our capabilities for Earth observation and expand our comprehension of celestial bodies and the universal impact of gravity. “The QGGPf could lead to breakthroughs in planetary science and fundamental physics,” Hyon stated.

For additional information on ESTO, please visit: https://esto.nasa.gov

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science.nasa.gov