Target practice just got galactic, with NASA confirming plans to shoot a rocket at an asteroid* to test a defence technique. NASA hopes the mission – planned for November – will demonstrate how to stop an asteroid from striking Earth in future.
The Double Asteroid Redirection Test (DART) is set to launch aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California at 1:20am EST on November 24.
NASA said that the DART will be the first demonstration of the “kinetic* impactor technique” that sends one or more large, high-speed spacecraft into the path of an asteroid in order to change its motion.
“Its target is the binary* near-Earth asteroid Didymos and its moonlet*, which pose no threat to Earth,” NASA said in a statement.
But in the event of a potentially hazardous* asteroid heading Earth’s way in the future, DART’s planetary defence technology is designed to prevent impact.
“While the Didymos primary body is approximately 780 metres across, its secondary body (the “moonlet”) is about 160-metres in size, which is more typical of the size of asteroids that could pose the most likely significant threat to Earth,” NASA said.
According to the NASA statement, the Didymos binary is being “intensely observed” using telescopes on Earth to precisely measure the asteroid’s properties before DART arrives.
Once launched, DART will deploy Roll Out Solar Arrays* (ROSA) to provide the solar power needed for DART’s electric propulsion* system.
“By utilising* electric propulsion, DART could benefit from significant flexibility to the mission timeline while demonstrating the next generation of ion* engine technology, with applications to potential future NASA missions,” NASA said.
After separating from the launch vehicle and after about a year of cruising, DART will intercept Didymos’ moonlet in late September 2022, when the Didymos system is within 11 million kilometres of Earth, enabling observations by ground-based telescopes and planetary radar to measure the moonlet’s change in momentum.
The DART spacecraft will then achieve the “kinetic impact deflection*” by deliberately crashing itself into the moonlet at a speed of approximately 6.6 km, with the aid of an on-board camera (named DRACO) and sophisticated* autonomous* navigation software.
The collision will change the speed of the moonlet’s orbit around Didymos by just a fraction of one per cent, but this small-seeming change will alter the moonlet’s orbital period by several minutes – enough to be observed and measured using telescopes on Earth.
An earlier risk assessment on the DART project schedule determined the primary launch period between July and August this year was no longer viable*, directing the DART project to this secondary launch window from November 24.
NASA said the decision related in part to overcoming technical challenges critical to the mission: the DRACO imager needed to be reinforced to ensure it could withstand the stress of launch, and delivery of the solar arrays was delayed due the Covid-19 pandemic.
“At NASA, mission success and safety are of the utmost importance, and after a careful risk assessment, it became clear DART could not feasibly and safely launch within the primary launch window,” associate administrator for the Science Mission Directorate Thomas Zurbuchen said. “To ensure DART is poised for mission success, NASA directed the team to pursue the earliest possible launch opportunity during the secondary launch window to allow more time for DRACO testing and delivery of ROSA, and provide a safe working environment through the Covid-19 pandemic.”
GLOSSARY
- asteroids: small, rocky bodies that orbit the Sun like planets
- kinetic: relating to or resulting from motion, movement
- binary: relating to, made of or involving two things
- moonlet: a small moon, a natural or artificial satellite
- hazardous: dangerous, risky, unsafe
- solar arrays: solar cells grouped together to make solar panels
- deflection: turning, diverting, deviating
- sophisticated: advanced, revolutionary, complex
- autonomous: independent, self-controlled
- propulsion: movement, act of driving or pushing forwards
- utilising: using, making use of, deploying
- ion: any electrically charged atom
- viable: workable, practical, usable
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QUICK QUIZ
- What does DART stand for?
- When is the proposed launch date?
- What does the kinetic impactor technique do?
- What does ROSA stand for?
- What is the approximate speed at which the DART will crash into the moonlet?
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CLASSROOM ACTIVITIES
1. Target Practice
Work with a partner and discuss and record the risks and rewards associated with this NASA experiment. What could go wrong and what is to gain? Divide a page into two columns, one headed RISKS and the other REWARDS and see how many of each you can come up with.
Time: allow 15 minutes to complete this activity
Curriculum Links: Science; Critical and Creative Thinking
2. Extension
The spacecraft plans to crash itself into the moonlet at around 6.6km an hour. That is not very fast considering our cars travel at 100km per hour on freeways. Why do you think the impact would be greater in space?
Are there any questions you still have about how this works? If so, chat with another class member.
Time: allow 10 minutes to complete this activity
Curriculum Links: Science; Critical and Creative Thinking
VCOP ACTIVITY
1. Summarise the article
A summary is a brief statement of the main points of something. It does not usually include extra detail or elaborate on the main points.
Use the 5W & H model to help you find the key points of this article. Read the article carefully to locate who and what this article is about, and where, when, why and how this is happening. Once you have located this information in the article, use it to write a paragraph that summarises the article.
