[Epoch Times, Hydref 14, 2022](comprehensive report of the Epoch Times reporter Li Yan) NASA announced on Tuesday (October 11) that its mission “Double Asteroid Redirection Test” (Double Asteroid Redirection Test) The Redirection Test, DART) has successfully redirected the mission. orbit of an asteroid millions of miles away.
This is the first time that humans have purposely changed the motion of a celestial body, and it is also the first time that asteroid deflection technology has been fully demonstrated. After the DART spacecraft slammed into the asteroid Dimorphos, scientists found in a two-week follow-up analysis that the kinetic impact sent the asteroid around its parent planet Didymos. ) orbital time reduced by 32 minutes.
Before this, the 170-metre-diameter Deimos orbited the 780-metre-diameter Didymos for 11 hours and 55 minutes.
The margin of uncertainty for this measurement is about plus or minus two minutes.
Astronomers use telescopes – including the Hubble Space Telescope – to measure how much its cycle time varies. The minimum requirement for a successful DART mission, according to NASA metrics, is a 73-second change in the orbital period of the target asteroid Deimos.
NASA Administrator Bill Nelson called it “a watershed moment for the planetary defense mission.” “We all have a responsibility to protect our planet, which is our only home after all… This mission shows that NASA is working hard to prepare for whatever the universe throws at us to us,” he said.
Neither Deimos nor Didymus pose any danger to Earth following a controlled collision between DART and Deimos.
Lori Glaze, director of NASA’s Planetary Science Division, said the current observations are an important step in understanding the impact of the DART spacecraft impact. With the new data, astronomers can better assess how similar techniques can deflect an asteroid’s orbit to protect Earth from its impact.
NASA said the focus now turns to measuring the efficiency of momentum transfer during DART’s roughly 14,000 mile per hour impact, including further analysis of the “ejectors” impact.
The DART spacecraft was launched last year. It was built and operated by Johns Hopkins University’s Applied Physics Laboratory (APL) and the mission was managed by NASA’s Planetary Defense Coordination Office.
Responsible editor: Li Yuan#
One Response
It is possible that not the change in the orbit of Dimorphos did play the main role in the observed post-impact features of the mutual asteroid shadowing.
This role could be played by an asymmetric and optically dense near-surface “meteoroid cocoon”, consisting of its material ejected into the hemisphere. Therefore, yet it cannot be ruled out that after the dissipation and fallback of this material onto the surface of Dimorphos, its orbit will be partially or almost completely “restored”.