A new method proposed by Justin Atchison and colleagues from Johns Hopkins University Applied Physics Laboratory aims to accurately measure the mass of smaller potentially hazardous asteroids (PHAs), a crucial factor for planetary defense. Traditional radio-frequency tracking is insufficient for asteroids less than 140 meters in diameter. The proposed technique involves a reconnaissance spacecraft flying extremely close to the asteroid, at an altitude of just three times its diameter, while a deployed CubeSat maintains a distance of approximately 10 km. This proximity, combined with precise instrumentation like Laser Rangefinding or High Precision Doppler Instruments, and advanced optical navigation systems, will enable the measurement of minuscule velocity changes caused by the asteroid's gravitational pull. This is particularly relevant for scenarios like a potential mission to asteroid 2024 YR4, which has a 4% chance of impacting the moon in six years, requiring flyby speeds of 22 km/sec.