1,212
edits
Changes
no edit summary
== Why Deployment? ==
* Generally frequency range for nano-satellites lies in VHF band. Therefore, the antenna length will lie in range of 10 - 150 cm (varies with frequency). In vibration, higher is the mass farther from the base (source of vibration), lesser is the natural frequency of the satellite. This means that if antennae are not deployed deployable, but rather fixed the the satellite body (like in the case of Pratham), then they are more vulnerable to damage due to resonance during launch, since the fundamental frequency will approach the lower limit imposed by the launch vehicle. This imposes the requirement of antenna deployment so as to keep mass closer to the base (source).
* Also if we keep antenna undeployed then we have to increase its mass to increase stiffness. It can affect the mass budget constraint.
* Another major reason is that it covers larger space on launch vehicle.
== Design Considerations ==
* Side panel length is major determinant of antenna deployment. If the antenna length is larger than the side length then we have roll or wind up the antenna.
* If power is an issue then antenna should be deployed in such way that the shadow should on the solar panels should be minimized to maximize the power for charging.
* Deployment of antenna is usually done on different sides to avoid the collision or entangling of antennae while deployment.
* If all the antennas are to deploy on same side they should not be deployed in the same plane, else there can be collision of antennae
* Heating element can be covered with some thermal insulator with only some part of heating element kept open to environment on which retention wire is tied.
* Nuts and bolts used for attaching antenna should be taken into account when designing and analyzing the deployment mechanism.
----
If you are done reading this page, you can go back to [[Mechanical Subsystem]].