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Cratering the Moon Challenge
Preliminary Design by:
Nishant SP

MES School

Centrapetal Projectile Accelarator

The surface of the moon is covered by the hard regolith.  To penetrate this hard layer, it is necessary to beam the projectile with high velocities to the surface of the moon.

photo of surface of moon

Keeping the above requirement in mind, the centripetal projectile accelerator has been designed.
The centripetal projectile accelerator is a circular structure which consists of an extensible string and the projectile attached to its end. The other end of the string has been connected to the electric motor. An outlet has been made tangentially to the outer structure to release the projectile.

illustration represents the working of the centripetal projectile accelerator

The above illustration represents the working of the centripetal projectile accelerator.
Internal representation of the centripetal projectile accelerator
Internal representation of the centripetal projectile accelerator.

Working: At first, the extensible elastic string containing the projectile is attached to the motor. When the electric current is made to flow through the circuit, the motor begins to rotate. The string unwinds and starts to revolve under the influence of the centripetal force given by  F=MV^2/R and an acceleration of V^2/R where M is the mass of the projectile, V is its velocity and R is the length of the string. The increase in the power of the motor would increase the acceleration further, till the string containing the projectile touches the internal surface of the accelerator. When the projectile reaches the desirable velocity, and the centripetal projectile accelerator aligns with the launch angle, it is detached from the string released through the tube. The projectile travels in straight line through the tangential component of the centripetal projectile accelerator as shown in the above image.

Expert response from Jennifer Heldmann:
Good preliminary design.  For the next round of designs, how will you measure the exact angle of impact?  Also how will you measure the amount of excavated ejecta?  Always remember "safety first" and use caution when using an electric motor.


 FirstGov  NASA

Editor: Linda Conrad
NASA Official: Liza Coe
Last Updated: October 2007
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