Double Asteroid Redirection Test : How much will the impact alter the orbit of Dimorphos?!
The DART mission has blasted off, sending an "impact spacecraft" to a binary asteroid system (1). The mission is designed to determine if we can alter the movements of an asteroid, at least those large enough to cause severe damage to earth.
The target, Dimorphos, itself orbits a larger asteroid, Didymos, with a period of about 12 hours. That is the reason this particular target was chosen, since ground-based telescopes should be able to measure any significant change in the target's orbital period.
According to The Johns Hopkins University Applied Physics Laboratory website (2), the DART impactor will be hitting Dimorphos head-on at a speed of ca. 6.6 km/s (15,000 mph). The impactor weighs about 550 kg, and the target weighs in at about 4.8 billion kg (3). This is quite a significant difference, but the impact is expected to decrease the orbital period of Dimorphos by about 10 minutes.
Any asteroid-physics freaks out there who might care to guess about the accuracy of such an estimate? Is it possible that the magnitude of any change in the orbit may depend in part on the nature of the target? A pile of rubble, or a really hard target, might result in a different change in orbital time. It would seem that ejecta (more or less) from the impact could cause a variance to the orbital dynamics as momentum from the impact imparted to the target would be different.
In any event, the predicted result seems like a bit of a WAG, at least to some of us.
"Nasa Dart asteroid spacecraft: Mission to smash into Dimorphos space rock launches"
(1) https://www.bbc.com/news/science-environment-59327293
"Impactor Spacecraft"
(2) https://dart.jhuapl.edu/Mission/Impactor-Spacecraft.php
"Double Asteroid Redirection Test "
(3) https://nssdc.gsfc.nasa.gov/nmc/spac...action?id=DART
