Lunar Reconnaissance Orbiter

The Lunar Reconnaissance Orbiter or LRO was launched by NASA in 2009. The LRO has created a 3 – D map of the moon’s surface at 100 metre resolution.

What are the key contributions of LRO?

• In 2019, LRO founded the crash site of the moon lander Vikram. The Vikram lander was carried by Chandrayaan – 2 along with the Pragyan rover. However, ISRO lost contact with the lander before the scheduled touch down. LRO confirmed the crashing of Vikram lander by comparing its previous images of the site. However, the Chandrayaan orbiter is orbiting the polar orbit of the moon successfully.
• In 2015, the orbit of LRO was altered to fly 20 km above the moon’s surface. This was done to increase the resolution of the images.
• In 2013, NASA tested one way communication with LRO.
• LRO confirmed the presence of water in Cabeus crater in the south pole of the moon.

From which spacecraft did LRO face collision threat?

India’s Chandrayaan – 2. The LRO and Chandrayaan – 2 were to come dangerously close to each other on October 20, 2021. However, the Chandrayaan – 2 performed collision avoidance to avert the possible conjunction event. Both NASA and ISRO agreed that the situation warranted collision avoidance. Based on this, ISRO orbiter was moved away.

How did Chandrayaan – 2 managed to avoid collision with LRO?

The collision was to occur near the north pole of the moon. The space stations of the respective countries found that the radial separation between the spacecrafts will be 1000 metres. Thus, a Collision Avoidance Manoeuvre (CAM) was warranted. In a CAM, a small impulse is generated by a short burn. The firing is done using reaction control system. The reaction control systems are usually used to change the altitude of the orbits. This changes the orbital trajectory.