Trans Lunar Injection (TLI)

Why in news?

• The Indian Space Research Organisation (ISRO) has successfully performed the TransLunar Injection (TLI) to slingshot Chandrayaan-3 towards the moon.
  • TLI has been performed successfully on many missions to the Moon, including the Apollo missions, the Chang’e missions and the Artemis missions.

About Trans Lunar Injection (TLI):

• The Trans Lunar Injection (TLI) manoeuvre is a vital space travel technique used to launch a spacecraft from Earth’s orbit and place it on a track beyond the Moon. 
• The TLI is performed when the spacecraft is at a specific point in its orbit known as the ‘perigee’ or the closest point to Earth. 
• By firing its engines at this strategic moment, the spacecraft gains enough speed to break free from Earth’s gravitational pull and embark on its journey toward the moon.
• Once the TLI is successfully completed, the spacecraft is put on a lunar trajectory, and it will continue its journey to the Moon without further propulsion from Earth.
• The spacecraft typically enters a transfer orbit, which is an elliptical path that intersects with the Moon’s orbit. It continues to travel in its highly eccentric orbit until it reaches the Moon’s surface.
• As the spacecraft approaches the Moon, it may perform additional manoeuvres, such as lunar orbit insertion (LOI), to enter into lunar orbit or land on the lunar surface, depending on the mission’s goals.

PRACTICE QUESTION:

Consider the following statements regarding ‘Trans Lunar Injection (TLI)’:

1. It is performed when the spacecraft is at apogee.

2. Once the TLI is successfully completed, the spacecraft will continue its journey to the Moon without further propulsion from Earth

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer