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Illustration of the DART spacecraft flying towards the asteroids Dimorphos and Didymos. Image credit: NASA/Johns Hopkins/APL
ANGKASA LEPAS | HOUSTON: Agensi Aeronautik dan Angkasa Lepas (NASA) akan menghentam dengan sengaja asteroid menggunakan kapal angkasa tepat jam 7.14 pagi waktu Malaysia pada 27 September 2022 waktu Malaysia iaitu misi pertama bertujuan melindungi bumi.
Projek yang dipanggil Ujian Pengalihan Asteroid Berganda (DART) dengan sengaja akan merempuh angkasa lepas untuk melihat sama ada batuan angkasa pada suatu hari nanti boleh mengelak daripada dimusnahkan oleh kesan berpotensi bencana daripada asteroid.
"Ini adalah permainan billiard kosmik yang sangat rumit. Apa kita mahukan ialah menggunakan sebanyak mungkin tenaga (yang kita boleh) dari DART untuk menggerakkan asteroid," kata ahli pasukan penyiasat DART NASA, Alan Fitzsimmons dalam satu temu bual, menurut Anadolu Agency (AA).
Misi DART dilancarkan pada November tahun lalu dari Pangkalan Angkatan Angkasa Vandenberg di California.
Hari ini, pegawai misi akan menyerahkan kawalan angkasa lepas untuk membawanya sendiri ke angkasa lepas kira-kira 10.5 juta kilometer dari bumi dengan kamera khas dari luar kapal itu akan merakamkan gambar pelanggaran kosmik yang tidak pernah disaksikan sebelum ini.
"DART mengubah fiksyen sains menjadi fakta sains dan menjadikannya bukti proaktif dan inovasi NASA untuk manfaat semua. Ujian ini akan membantu membuktikan satu cara yang berdaya maju untuk melindungi planet kita daripada asteroid berbahaya sekiranya ia pernah ditemui yang menuju ke bumi," kata Pentadbir NASA, Bill Nelson dalam satu kenyataan.
Matlamat utama NASA adalah untuk melihat sama ada ia boleh melencongkan asteroid secara manual daripada menyerang planet sekiranya saintis melihat lebih awal asteroid berada di laluan pelanggaran dengan bumi.
"Perkara yang menjadikan bencana alam ini berbeza ialah jika kita melakukan persiapan, kita sebenarnya boleh mencegahnya," kata Bruce Betts, ketua saintis di Planetary Society dalam satu temu bual.
"Itu adalah perbezaan yang besar berbanding dengan banyak bencana alam berskala besar lain."
Kapal angkasa DART akan menyasarkan batu angkasa gergasi (diameter 160 meter) yang dikenali Dimorphos pada kelajuan 24,140 km sejam.
NASA berkata, matlamatnya bukan untuk melenyapkan asteroid tetapi untuk melihat sama ada perlanggaran itu boleh mengubah orbit batu angkasa.
Menurut agensi angkasa Amerika Syarikat, tiada asteroid yang diketahui lebih besar daripada 137 meter menghentam bumi dalam tempoh 100 tahun akan datang.
Oleh itu, walaupun misi DART gagal, saintis akan dapat mengekstrak maklumat penting daripada eksperimen yang boleh melindungi planet suatu hari nanti.
Berikut Adalah Kenyataan Penuh NASA :
This image of the light from asteroid Didymos and its orbiting moonlet Dimorphos is a composite of 243 images taken by the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) on July 27, 2022. Credits: NASA JPL DART Navigation Team
DART Sets Sights on Asteroid Target
NASA’s Double Asteroid Redirection Test (DART) spacecraft recently got its first look at Didymos, the double-asteroid system that includes its target, Dimorphos.
On Sept. 26, DART will intentionally crash into Dimorphos, the asteroid moonlet of Didymos. While the asteroid poses no threat to Earth, this is the world’s first test of the kinetic impact technique, using a spacecraft to deflect an asteroid for planetary defense.
This image of the light from asteroid Didymos and its orbiting moonlet Dimorphos is a composite of 243 images taken by the Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) on July 27, 2022.
From this distance—about 20 million miles away from DART—the Didymos system is still very faint, and navigation camera experts were uncertain whether DRACO would be able to spot the asteroid yet. But once the 243 images DRACO took during this observation sequence were combined, the team was able to enhance it to reveal Didymos and pinpoint its location.
“This first set of images is being used as a test to prove our imaging techniques,” said Elena Adams, the DART mission systems engineer at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland.
“The quality of the image is similar to what we could obtain from ground-based telescopes, but it is important to show that DRACO is working properly and can see its target to make any adjustments needed before we begin using the images to guide the spacecraft into the asteroid autonomously.”
Although the team has already conducted a number of navigation simulations using non-DRACO images of Didymos, DART will ultimately depend on its ability to see and process images of Didymos and Dimorphos, once it too can be seen, to guide the spacecraft toward the asteroid, especially in the final four hours before impact. At that point, DART will need to self-navigate to impact successfully with Dimorphos without any human intervention.
“Seeing the DRACO images of Didymos for the first time, we can iron out the best settings for DRACO and fine-tune the software,” said Julie Bellerose, the DART navigation lead at NASA’s Jet Propulsion Laboratory in Pasadena, California. “In September, we’ll refine where DART is aiming by getting a more precise determination of Didymos’ location.”
Using observations taken every five hours, the DART team will execute three trajectory correction maneuvers over the next three weeks, each of which will further reduce the margin of error for the spacecraft’s required trajectory to impact.
After the final maneuver on Sept. 25, approximately 24 hours before impact, the navigation team will know the position of the target Dimorphos within 2 kilometers. From there, DART will be on its own to autonomously guide itself to its collision with the asteroid moonlet.
DRACO has subsequently observed Didymos during planned observations on Aug. 12, Aug. 13 and Aug. 22.
Johns Hopkins APL manages the DART mission for NASA's Planetary Defense Coordination Office as a project of the agency's Planetary Missions Program Office. DART is the world's first planetary defense test mission, intentionally executing a kinetic impact into Dimorphos to slightly change its motion in space.
While the asteroid does not pose any threat to Earth, the DART mission will demonstrate that a spacecraft can autonomously navigate to a kinetic impact on a relatively small asteroid and prove this is a viable technique to deflect an asteroid on a collision course with Earth if one is ever discovered. DART will reach its target on Sept. 26, 2022.
For more information about the DART mission, visit:
https://www.nasa.gov/dartmission
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