UPSC Essentials: One word a day – DART, the space mission

Word: DART

Subject: Science and Technology (Space)

Relevance: NASA’s DART (Double Asteroid Redirection Test) mission will be the first demonstration of a method that could be used to protect Earth from asteroids that could pose a threat to it in the future. Being the first of its kind, this mission is important. Also, asteroids are often in news. Any unique aspect related to the asteroids should not be missed. Know the role of ESA. Do not miss solving the MCQ below.

Why in news?

—NASA’s DART spacecraft is scheduled to crash into the asteroid Dimorphos at approximately 7.14 PM EDT on September 26 (4.44 AM IST on September 27).

What is DART?

— NASA’s Double Asteroid Redirection Test (DART) is the world’s first full-scale mission to test technology for defending Earth against potential asteroid or comet hazards.

— It was launched on a SpaceX Falcon 9 rocket from Space Launch Complex 4 East at Vandenberg Space Force Base in California.

What is its relevance?

— The mission will test a method that could be used to redirect asteroids that pose a threat to our planet.

— Using the impact of a massive object like a spacecraft to divert asteroids is called the “kinetic impact method” of asteroid impact avoidance.

— According to Robert Braun, head of the Johns Hopkins Applied Physics Laboratory’s (APL) Space Exploration Sector,

“This is humanity’s first planetary defence test mission. This is the first time defence technology will be tested in a civilian mission. Also, we do not know the exact shape of the target or what it is made of. But we intend to understand its shape and composition based on the change in its orbit and based on the ejected material.”

Why is the crash of DART with Dimorphos important?

— The 160-meter-wide asteroid Dimorphos orbits the much larger asteroid Didymos, which is about 780 meters wide. After DART crashes into Dimorphos, it will ever so slightly change the way that it orbits Didymos.

— Telescopes on our planet and in space– including the Webb Telescope and Hubble– will be trained on this asteroid system to take measurements of the changes in the system.

— While Dimorphos poses no actual threat to Earth, scientists will compare the data from DART’s actual impact with the many computer-generated simulations they have already made. This will help ascertain whether the kinetic impact method will be effective as a mitigation strategy in the event of an actual asteroid threat.

What else you should know?

— The exact mass of Dimorphos is unknown but NASA estimates it to be five billion kilograms. DART weighs around 600 kilograms. According to NASA, this would be similar to crashing a golf cart into the great pyramid.

“This is intended to be a small nudge that will slightly change the position of the asteroid. In the event of an actual predicted threat, this is something that we would do five, ten or twenty years in advance,” Nancy Chabot, DART coordination lead at NASA, said during the press conference.

— The only instrument on board the DART spacecraft is DRACO, or Didymos Reconnaissance and Asteroid Camera for Optical navigation. The high-resolution camera will capture images of Didymos and Dimorphos while simultaneously supporting DART’s autonomous guidance system.

— Apart from the James Webb Telescope, the Hubble Telescope and various other space telescopes here on Earth, a satellite much closer to the vicinity of the asteroid system will also have its eyes trained on the impact. This is the CubeSat called LICIACube.

— According to the Italian space agency Agenzia Spaziale Italiana, which built the CubeSat, LICIACube detached itself from DART on September 12 and has begun operating autonomously. The two cameras on board the CubeSat will transmit back images even after the DRACO can no longer do so.

— Apart from helping test an asteroid mitigation strategy, the DART mission will also test technologies like the DRACO camera and an advanced version of NASA’s compact Roll-Out Solar Arrays (ROSA). The successful demonstration of these technologies will make them important tools in the “toolbox” for future space exploration.

—Also, according to the European Space Agency,

“In the world’s first test of asteroid deflection, Hera will perform a detailed post-impact survey of the target asteroid, Dimorphos – the orbiting Moonlet in a binary asteroid system known as Didymos.
Once NASA’s DART mission has impacted the moonlet, Hera will turn the grand-scale experiment into a well-understood and repeatable planetary defence technique.

Demonstrating new technologies from autonomous navigation around an asteroid to low gravity proximity operations, Hera will be humankind’s first probe to rendezvous with a binary asteroid system and Europe’s flagship Planetary Defender.”

Is there actually a chance of Earth being threatened by an asteroid impact in the near future?

— Thomas Zurbuchen, the associate administrator for the Science Mission Directorate at NASA explained the reasoning for such a mission.

“We are not aware of a single object right now threatening the earth in the next 100 years. But I guarantee you that there will eventually be one. We can deduce that from the geological records of our planet and even data from the Moon. We want to test the technology now so that it is ready in case we ever need it,” he said.

“This test will not affect the asteroid system in any way that it could become a threat to the Earth. That is not scientifically possible,” added Zurbuchen.

Point to ponder: The greatest threat to life on Earth may come from space. Do you agree?

MCQ:

Which of the pair is not correctly matched?

a) DART— to test an asteroid mitigation strategy.

b) Hera — to perform a detailed post-impact survey of the target asteroid, Dimorphos.

c) LICIACubea— CubeSat riding with DART provided by the Italian Space Agency (ASI).

d) DARCO — to assist NASA’s efforts to identify and characterize the population of near-Earth objects.

Answer to previous MCQ: Case Study of the week— Road Safety: ‘Better Late than Never’ (d)

Post-Read Q&A

Can you recall what you read?

1. What are DART, Hera, LICIACubea, DARCO etc.?

2. Why is DART a unique mission of NASA?

3. Is there actually a chance of Earth being threatened by an asteroid impact ?

4. Is ESA related to DART mission?

(sources: nasa.gov, esa.int)