Can anyone tell me that why on rotating the spacecraft its pointing becomes stable and how it is useful in interplanetary research.
For example JUNO spacecraft
Fundamentally the angular momentum is conserved. The vehicle can have rotation on three axes called roll, pitch and yaw. Rotation may stabilize the pointing in one direction or around a circle. Photography and communications are simplified.
Hi Akash,
Take a look at rotational dynamics and stability in literature. The answer to your question is explained mathematically in the below link:
http://farside.ph.utexas.edu/teaching/336k/Newtonhtml/node71.html
Actually the pointing may not be stable! A spacecraft in the space environment usually has negligible disturbance, so it angular momentum is conserved. Energy is not conserved if there are dissipative forces like propellant slosh in the propellant tanks. Energy dissipation lowers the rotational energy to its lowest state, which results in the spacecraft spinning about its maximum inertia axis, which must also point in the direction of the angular momentum vector. Therefore, the spacecraft will reach a stable spin pointing direction along the angular momentum vector. If dissipative forces are not present the dynamics becomes more complicated and Rasit Abay's answer should be applied.