Recently, NASA announced that "its Double Asteroid Redirection Test (DART) spacecraft has opened its 'eyes' and returned its first image from space." ”
DART is the first mission to demonstrate asteroid deflection using a powered impactor. Previously, the DART spacecraft has successfully launched from the Vandenberg Space Force base in California aboard SpaceX's Falcon 9.
Figure | DART spacecraft (Source: NASA)
"DART is a critical next step in planetary defense. While on the surface, this is a simple test, we won't fully understand what will happen until we do it. Cristina Thomas, professor of astronomy at the University of Northern Arizona and head of the DART Observation Working Group, said.
It is understood that the image transmitted by the DART spacecraft is not only dark space, but has more than ten stars, which are particularly conspicuous in the black background. The image was taken about 2 million miles from Earth, surrounded by the constellations of Perseus, Aries and Taurus.
Based on this image, NASA's Jet Propulsion Laboratory will be able to accurately confirm the flight position and direction of DART and point it at objects of interest, such as Messier 38, through subsequent adjustments, thus capturing the latest moving images of them.
"This is an important milestone for the DART spacecraft and the team." FOR DART to be able to transmit images back so quickly, NASA commented.
Figure | Images of stars taken by DRACO cameras (Source: NASA)
Notably, the DART spacecraft used a high-resolution camera called DRACO (Didymos Reconnaissance and Asteroid Camera for Optical Navigation), which is the only instrument on board the spacecraft.
DRACO drew on the imager on NASA's New Horizons spacecraft, which is highly acclaimed in the industry for capturing the first close-up image of Pluto. DRACO is inspired by it, and perhaps a tribute.
Sending back images is just the first step, and DRACO's ultimate goal is to reach and observe the asteroid Dimorphos, which orbits a larger asteroid called Didymos, which means twin in Greek.
DART will simultaneously test new technologies and provide critical data to enhance modeling and prediction capabilities to help scientists better prepare for asteroids that may pose a threat to Earth.
Specific missions include demonstrating the dynamic effects of Dimorphos; changing the orbital period of the asteroid' binary stars; using ground-based telescope observations to measure the change in periods before and after impacts; and measuring the impact of impacts and the resulting ejecta on the asteroid.
"Dust and volatiles observations will help us understand the composition of asteroids and the speed, direction, and properties of the material ejected by the impact." Nathan Roth, a member of the DART Observation Working Group, said, "Based on the brightness of the asteroid at each wavelength, we will be able to understand the size distribution of dust particles in the ejecta. With Weber's high-resolution imaging, we will be able to understand jets or other structures in the jet. ”
Nancy Chabot, a planetary scientist at johns Hopkins University's Applied Physics Laboratory, noted that the force of the DART spacecraft hitting Dimorphos did not "destroy" the asteroid. Previously, Chabot had been involved in the construction of the spacecraft.
"It's just going to give it a little push, and it's going to change its path around the larger asteroid." Chabert said. The test is designed to help scientists understand how much momentum is needed to deflect an asteroid as it sails toward Earth on a given day.
(Source: NASA)
In fact, in addition to launching the DART probe for impact testing, key to NASA's planetary defense efforts includes the Near-Earth Object (NEO) Observation Program, which consists of projects to find, track, and characterize near-Earth objects.
It is understood that NEOs are a general term for "asteroids, comets, and large meteoroids whose orbits intersect the Earth's orbit and therefore have the potential to impact." "Such objects pose the most concerned potential risk to Earth, and even in NASA's view, observations of NEAR-Earth objects should continue to be the focus of global search efforts."
Typically, NASA uses telescopes around the world to search for NEOs, track them in the sky to determine their orbits, and obtain information about their size, shape, and composition.
In order to inform observers around the world of the discovery of near-Earth objects, so that follow-up observations can be collected in time for identification and orbit calculations, NASA has also established a small planet center. The minor planet center aggregates celestial data from observers, calculates newly discovered asteroid orbits, and conducts long-term analysis of the possible future position of dangerous asteroids relative to Earth to identify and warn of any impact hazards.
Thankfully, according to scientists, "in the next 100 years, there will be no known asteroids larger than 140 meters in diameter that will have the opportunity to hit Earth." ”
With a diameter of 140 meters, it can be said to be a node, equivalent to a small football field, and the threat to the earth posed by objects close to or larger than it will be huge and immeasurable.
Although the possibility is very small, the danger of the Earth being hit has always existed. That's because less than half of the estimated 25,000 NEO objects greater than or equal to 140 meters have been discovered, and the precautionary DART is preparing for this possibility.
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reference:
https://phys.org/news/2021-12-eye-nasa-dart-images-space.html