Scientists are researching asteroid-prevention scheme

NASA's Double-Asteroid Redirect Test (DART) made history on September 26, 2022, when it impacted Didymos' moonlet, Dimorphous. 

The goal was to test the "Kinetic Impact" method of defending against potentially hazardous asteroids (PHAs). 

DART shortened Dimorphos' orbit by 22 minutes, according to follow-up observations. The hit increased the moonlet's tail. Hollywood reminds us that a planet-killing asteroid can approach Earth before we can stop it. 

Near Earth Asteroids could become hazards someday. Space organisations globally watch their proximity to Earth. 

According to a new research by satellite experts, a rapid-response kinetic impactor mission may deflect a PHA before it hit Earth. 

Adalberto Domnguez, Vctor M. Moreno, & Francisco Cabral conducted the study, published in Acta Astronautica. This corporation specialises in GNC & AOCS for commercial, military, research, & space exploration. 

The research team discussed GMV's recent GNC work for a Kinetic Impact mission in their study. Space organisations have studied diverting asteroids that threaten Earth in recent years. 

Nuclear standoff, gravity tractor, & kinetic impactor are regarded the most promising. The nuclear option includes detonating a nuclear weapon near an asteroid, whereas the gravity tractor requires flying around it. 

Only kinetic impactors can deflect PHAs, stated Dominguez. “The application of the nuclear standoff has yet to be shown, & its target would be asteroids many kilometres in diameter. 

Asteroids aren't a threat anymore because most are monitored. The 1967 Outer Space Treaty banned nuclear tests in outer space. The gravity tractor targets hundreds-meter asteroid targets. 

The collision of one of these asteroids might destroy an entire city. The gravity tractor would need years to diverge from the asteroid." For their work, Dominguez & his colleagues developed a GNC for a kinetic impactor. 

This is crucial for any robotic mission requiring autonomy. Small-body Maneuvering Autonomous Real-Time Navigation was one of the most advanced parts of the DART mission (SMART Nav). 

This technology directed DART during its last approach to Dimorphos, as mission controllers couldn't make course adjustments. A KI mission planned to deflect an asteroid at the last minute will also require autonomy. 

When it hits the asteroid, the spacecraft will need a relative velocity of 3 to 10 km/s (10,800 to 36,000 km/h) (6,710 and 22,370 mph). So, Dominguez. “Another challenge is that we know nothing about the asteroid we're targeting. So, the GNC must be adaptable. 

The size of the asteroids, around 100 metres, complicates navigation. Imagine impacting an object with undetermined dynamics and form at km/s without making any corrections from the ground. 

Dominguez says this makes the GNC the most crucial subsystem piece since it targets the asteroid & does course corrections at the last second. As the mission unfolds, these modifications must be computed & applied in situ. 

The team tested algorithms routinely used by spacecraft (navigation, imaging processing, etc.) to ensure their GNC design could do such computations. The former comes in two types, said Dominguez. 

The two primary types of guidance algorithms are proportional navigation & predictive feedback. Proportional navigation algorithms employ the target & impactor's current positions to calculate the manoeuvre needed to hit. 

Proportional navigation is like a missile's guidance; corrections are made every second to correct the spacecraft's trajectory. Predictive feedback guidance uses previous & present data to estimate the spacecraft & impactor's future state. 

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