OSIRIS-REx to study Asteroid Apophis

• Context (LM): The former OSIRIS-REx spacecraft sets off on a (seven-year, 4 billion-mile journey) journey to study asteroid Apophis.

Asteroid Apophis

• Asteroid Apophis is better known as the ‘God of Chaos’.
• It is a near-Earth object (NEO) estimated to be about 1,100 feet (340 meters) across.
• Asteroid Apophis is made of silicate materials and nickel-iron (different from carbon-rich, “C-type” Bennu).
• It originated in the main asteroid belt between Mars and Jupiter.

Why Study Apophis?

• Discovered in 2004, Apophis gained notoriety as one of the most hazardous asteroids that could impact Earth.
• Apophis is expected to “safely pass close to Earth on April 13, 2029, the closest approach to Earth by an asteroid of this size that scientists have known about in advance.
• Apophis’ close encounter with Earth is expected to change the asteroid’s orbit and the length of its 30.6-hour day.
• It was officially taken off from NASA’s Potentially Hazardous Asteroids list (PHAs).

Asteroids

• Asteroids are small, rocky objects that orbit the Sun like planets, but they are much smaller than planets and are irregular shaped (not all round like planets).
• Formed around 4.6 billion years ago, they are remnants of protoplanetary disk- the cloud of gas and dust from which the sun and planets formed.
• Size: Some are tiny, only a few metres across while others can be several kilometres wide.
• Types:
  1. C-type (Carbonaceous) Asteroids: They make up 75% of the known asteroids.
  2. S-type (Silicate or Stony) Asteroids: They account for 17% of known asteroids.
  3. M-type (Metallic) Asteroids: They are made up of nickel-iron and are found in the middle region of the asteroid belt.
• Asteroids are divided into three categories:
  1. Asteroids in the main asteroid belt, between Mars and Jupiter.
  2. Trojans (name comes from Greek mythology), which are asteroids that share an orbit with a larger planet.
  3. Near-Earth Asteroids (NEA): It has orbits that pass close to the Earth.
     • Earth Crossers: Those that cross the Earth’s orbit. More than 10,000 such asteroids are known, of which over 1,400 are classified as potentially hazardous asteroids (PHAs).