R Lang & Associates

          HOME                      ABOUT                      SPACE & AVIATION                     MEDICAL SCIENCE



NASA’s DART Mission Deemed Successful

 

 

October 11, 2022

The Double Asteroid Redirection Test has been deemed successful after determining that after the DART spacecraft slammed into the asteroid Dimorphos at 14,000 mph on September 26th, it changed its trajectory.

This is the first time Man has intentionally changed the motion of a celestial object, and a step toward progress of being able to deter a potentially hazardous asteroid away from Earth in the case of a possible collision.

Previously, Dimorphos was orbiting about the parent asteroid Didymos at a period of 11 hours and 55 minutes.  After the DART impact, the orbital period changed to 11 hours and 23 minutes, or 32 minutes less (plus or minus 2 minutes) which is about a 4.5 percent change.  Dimorphos is now orbiting Didymos a little bit closer, indicating that DART has changed its trajectory.

It was reported that NASA was hoping for a change in Dimorphos’ orbital period by at least 10 minutes.  It was also reported that the impact caused a slight wobble to Dimorphos’ orbit, but may readjust.

The size of Dimorphos is over 500 ft wide which classifies it as a potentially hazardous asteroid (PHA).  Its mass is assumed to be 5 billion kgs.  Upon further studies of Dimorphos’ post-impact behavior, there should be a more accurate calculation of Dimorphos’ mass.  The rough estimate of the asteroid's orbital change (10 minutes versus the actual 32 minutes) is most likely related to the uncertain mass of Dimorphos.

 

 

The overall signs of the DART mission look good, resulting in a real-life application to deter an asteroid – and not merely an academic drill.  What the DART mission did to Dimorphos could be applied to a similar size asteroid that is headed toward Earth, providing the asteroid is impacted enough in advance.  The arc-angle of a deflected object increases substantially over distance, such that a small angle of deflection far away results in a wide length of arc after traversing the long distance, enough to deter an incoming asteroid from Earth with ease.  With some fine tuning, these kind of asteroids can not only be steered away from Earth but sent into the Sun, never to pose a threat to the planet again.

Dimorphos is now orbiting Didymos a little bit closer, indicating that DART has changed its trajectory.

 

 

1.  R Lang & Associates realizes the DART mission currently possesses (in its current form) the real-life ability to deter a potentially hazard asteroid from striking Earth.  Only the mass and speed of the impacting spacecraft need be adjusted per size of the PHA.  Mission accomplished !

2.  As some issues may be buzzing with activity in planetary defense, a likely scenario is whether the problem asteroid can be pre-hit by a small spacecraft to determine its exact mass, followed by sizing up a main impactor spacecraft (mass and speed) to then deflect the asteroid away from Earth.  Success in asteroid deflection is knowing exactly how the target asteroid is going to deflect, which points to the issue where the DART mission was really a “pre-hit” mission to determine the exact mass of Dimorphos.  The equations of motion can be simplified in outer space (since there is no air nor atmospheric resistance) and the exact mass of any asteroid easily determined by pre-hitting the asteroid.  Where there is little time, the smaller spacecraft is followed by the main impactor spacecraft by a matter of weeks (or months) and adjusting the speed and angle of attack of the impactor spacecraft after determining the mass from the pre-hit of the smaller spacecraft.  
{Footnote added 10-18-22}