DART Asteroid Mission: NASA’s First Planetary Defense Spacecraft

NASA’s Double Asteroid Redirection Test mission, or DART for short, is an ambitious project designed to test a method of deflecting an asteroid for planetary defense purposes, using the “kinetic impactor” technique.

Key figures of the DART mission

– Launch window: November 24, 2021 to February 15, 2022

– Rocket: SpaceX Falcon 9

– Target: Dimorphos

– Target distance from Earth: 6.8 million miles (11 million kilometers)

Estimated cost: $ 313.9 million (£ 227.9 million)

– DART impact window: Sep 26 to Oct 2, 2022

The DART mission is to be launched aboard a SpaceX Falcon 9 between November 24, 2021 and February 12, 2022, according to a statement from NASA. Although the delayed launch window does not affect the spacecraft’s initially expected time of arrival at its target in late September 2022, according to NASA officials.

DART’s target is a near-Earth binary asteroid (65803) Didymos and its moon Dimorphos. The DART mission is the first planetary defense mission to test asteroid deflection methods according to the Planetary Society.

Related: Apophis: The asteroid we thought could hit us

DART will deliberately impact the Moonlet Dimorphos at speeds of 4.1 miles per second (6.6 km / s). That’s a mind-boggling 14,760 mph (23,760 km / h). The impact is expected to cause the moon’s orbital speed to change by a fraction of a percent according to NASA. This slight shift should be enough to modify its orbital period by several minutes. According to NASA, Dimorphos’ orbit change around Didymos will be observed and measured by telescopes on Earth, to see if the mission was a success.

Target of the DART mission

DART will crash into Dimorphos, changing its orbit around Didymos. Ground observations will allow us to assess whether it has succeeded. (Image credit: NASA / Johns Hopkins APL)

While the threat from asteroid impacts is low, according to the Planetary Society, it is nonetheless a threat and we need to prepare for it. One need only look at past impact events such as the massive impact of the asteroid Chicxulub which is credited with the extinction of the dinosaurs 65 million years ago, to see the catastrophic effects that an impact can have. about life on Earth.

Early detection of near-Earth asteroids is the first step in planetary defense. About 30 new near-Earth asteroids discoveries are made every week and at the start of 2019 there were more than 19,000 near-Earth asteroids discovered according to NASA. DART will be the first mission to test an asteroid deflection technique.

Related: The greatest asteroid encounters of all time!

NASA’s DART mission is led by the Johns Hopkins University Applied Physics Laboratory (JHUAPL). The target of the mission is the binary asteroid system Didymos, which means “twin” in Greek. The system consists of a near-Earth asteroid (65803) measuring 0.48 miles (780 meters) in diameter and its moon Dimorphos measuring 525 feet (160 meters) in diameter.

While the pair do not pose a threat to Earth, they are perfect candidates for the DART mission as Dimorphos is roughly the same size as an asteroid which could pose the most likely threat to Earth (if the we were on a collision course with the planet) according to NASA. Their orbit around the sun is also close enough to Earth that ground-based telescopes can observe and measure the differences after the collision.

DART mission operations

Size comparisons between DART, Didymos, Dimorphos spacecraft and terrestrial objects. (Image credit: NASA / Johns Hopkins APL)

DART is a simple spaceship. According to JHUAPL, the box-shaped main vehicle measures approximately 3.9 x 4.3 x 4.3 feet (1.2 x 1.3 x 1.3 meters), which is about the size of a refrigerator. Each of the two large solar panels is 8.5 meters long when fully extended. The DART spacecraft contains only one instrument – Didymos Reconnaissance and Asteroid Camera for Optical Navigation (DRACO). (It turns out that if your main goal is to crash into an asteroid, you don’t need to take a lot of it with you).

Once the DART spacecraft launches on its SpaceX Falcon 9, it will deploy its Deployable Solar Panels (ROSA) to fuel itself for the trip to Didymos. Scientists tested the ROSA networks aboard the International Space Station in June 2017 and were found to be able to provide the power needed to support DART’s electric propulsion system, according to NASA. (In fact, NASA added larger versions of the ROSA matrices to the space station’s power grid.) System as part of its space propulsion.

According to JHUAPL, DART will be guided to its Dimorphos target by sophisticated autonomous navigation software. It is no small feat to locate a target 525 feet (160 meters) in diameter and 6.8 million miles (11 million kilometers) from Earth. According to JHUAPL, the navigation software is designed to identify both Didymos and Dimorphos and distinguish between the two, so that the DART spacecraft can be aimed at the smaller body – Dimorphos.

As the spacecraft approaches its target, a high-resolution on-board camera – DRACO will help navigate the DART spacecraft and take measurements of the target asteroid, including Dimorphos size and shape. DRACO is based on the LORRI camera from NASA’s New Horizons spacecraft.

DART companion: LICIACube

LICIACube will witness the impact of DART with Dimorphos. In this image, a team of engineers inspect the LICIACube at the John Hopkins Applied Physics Laboratory. (Image credit: NASA / Johns Hopkins APL / Ed Whitman)

According to NASA, the DART spacecraft will not make its journey to the near-Earth asteroid binary on its own, instead, the spacecraft will be joined by LICIACube (Light Italian Cubesat for Imaging Asteroids). LICIACube is a CubeSat supplied by the Italian Space Agency and built by the Italian aerospace engineering company Argotec.

According to NASA, the LICIRACube weighs just 31 pounds (14 kilograms) and is roughly the length of an adult’s hand and forearm. The small CubeSat has a very important job and will be deployed by DART about 10 days before the probe impacts Dimosphos. According to Argotec, LICIACube will stay behind and witness the impact, capturing images of the collision to help verify the effectiveness of the impact.

Post-impact investigations: Hera mission

ESA’s Hera mission will conduct post-impact surveys on DART’s impact with Dimorphos according to JHUAPL. The spacecraft is expected to launch in 2024 and reach the Didymos binary system in 2026.

ESA’s Hera spacecraft will be joined by two CubeSats. Together, they will carry out surveys of both Didymos and Dimorphos, paying particular attention to the crater left by DART’s collision with Dimorphos. The Hera mission also aims to determine an accurate mass of Dimosphos, according to JHUAPL.

While the two missions, DART and Hera, are designed and operated independently, together they will advance our understanding of planetary defense technologies. The team members from both missions are part of an international collaboration known as AIDA – Asteroid Impact and Deflection Assessment. According to ESA, AIDA is a large international collaboration between ESA, the German Aerospace Center (DLR), the Côte d’Azur Observatory (OCA), NASA and the Applied Physics Laboratory at John University Hopkins (JHUAPL).

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