In 2029, the asteroid 99942 Apophis will come within 32,000 km of the Earth’s surface, offering scientists the chance to closely investigate this body that once posed a major threat to the planet.
Coming closer than some of the artificial satellites in Earth’s orbit, the asteroid should be visible from the East without the need for a telescope or binoculars.
Five years before the approach, scientists have proposed potential missions to study the asteroid at the workshop Apophis T-5 Years: Knowledge Opportunity for the Science of Planetary Defense (Apophis T-5 Years: Knowledge Opportunity for Planetary Defense Science), organized by the European Space Agency (ESA).
In turn, NASA already has a visit to the rock planned: the OSIRIS APEX mission, which will reuse the asteroid sampler previously known as OSIRIS-REx (when it collected samples from the asteroid Bennu).
“Our planet’s gravitational pull is expected to alter the asteroid’s orbit, change how and how fast it rotates on its axis, and possibly cause earthquakes or landslides that will alter its surface,” explains the agency about the mission. “OSIRIS-APEX will allow scientists on Earth to observe these changes.
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Additionally, the spacecraft will dive toward the surface of Apophis — a rock-strewn asteroid made of silicate material and a mixture of metallic nickel and iron — and fire its engines to stir up loose rocks and dust. “This maneuver will give scientists a peek at the composition of the material just beneath the asteroid’s surface,” says NASA.
According to the website Space News, at the ESA workshop, private companies proposed other missions to the asteroid. Blue Origin’s idea, for example, is to use its Blue Ring spacecraft to deliver up to 13 payloads totaling up to two metric tons to the asteroid, launching in 2027 and approaching the target just before its closest approach to Earth.
NASA plans radar observations of asteroid Apophis
Another NASA line of study is the DROID mission (an acronym for Distributed Radar Observations of Interior Divisions), designed by the Jet Propulsion Laboratory (JPL).
“The DROID architecture requires a dedicated launch of three spacecraft: an ESPA Grande-class mothership and two CubeSats,” explains JPL in a proposal. “The mothership transports the CubeSats to Apophis, achieves the rendezvous cruise trajectory, performs high-resolution imaging with a narrow-angle camera, and acts as a DTE (Direct-to-Earth) node for the constellation.”
According to the description, once the physical characteristics of Apophis (shape, rotation, gravitational field) are sufficiently characterized, the mothership deploys both CubeSats, which carry a wide-angle camera and low-frequency radar and insert themselves into low orbits. coordinates to perform monostatic and bistatic radar observations”.
In 2021, the asteroid Apophis made a flyby of Earth, at which time astronomers made powerful radar observations to better define its orbit. Before that, NASA believed it had a chance of impact in 2068 but observations ruled out that possibility.
