In our recent blog post, Space-Proven Crystal Oscillators and Resonators, we took you on a journey into outer space. You saw what challenges both Crystal Oscillators and Resonators must go through while in the depths of space. We're about to take you on another similar, but more specific, journey!
Resonators in space will be the main focus of this post. Quartz resonators can be used for a variety of things in a spacecraft. I'm sure you can imagine the extreme challenges and rigors that the massive world of outer space can have on these delicate resonators.
In this post, you're going to learn 6 ways resonators are designed to withstand the intense space environment while also maintaining their great functionality.
1. Sealed with a Kiss? (More like Hermetically Sealed)
While traveling in space, one of the biggest requirements that the spacecraft has is to be hermetically sealed. For resonators, it is all the more important that their hermetic seal is not broken so their insides remain airtight. If the seal is broken, the resonator becomes susceptible to damage, including aging considerably in a short amount of time while also experiencing an increase in its equivalent series resistance.
2. Taking on Space Radiation
Without the protective layer of atmosphere that is found on Earth, a spaceship experiences regular bouts of Ionization radiation in addition to various other types of space radiation that can result in damage to the quartz resonator if it is not specially prepared for the journey. Today's resonators are made of a combination of elements in a specific ratio to provide the most protection against space radiation. The quartz resonator also carries a coating of a specially prepared polycarbonate which is able to absorb some of the radiation coming from space and prevent it from reaching the resonator.
3. Vibration Proof
Earth-based resonators would not be able to handle the amount of movement involved in the launching of a spaceship, and would likely break or get fractured during the launch. Other harmful side effects of the vibrations can include unwanted sidebands as well as a degradation in the phase noise performance. To survive launch vibration, the spaceship and all its components need to be designed in a specific manner, and made of carefully selected materials which would be able to withstand the often violent amounts of vibration that the craft will experience while entering and exiting the atmosphere of a planet.
4. Temperature Proof
In space, the temperature extremities experienced by the spaceship are unlike anything that people living within the Earth's atmosphere will ever experience. From the freezing cold of space to the burning temperatures of the unfiltered rays of the sun, the quartz resonator needs to be able to perform in the harshest of temperature conditions. For this, space-qualified crystals are developed to ensure that they do not experience too much expansion or contraction, and have a reduced temperature coefficient to be able to withstand extreme heat without melting.
5. Big Job, Smaller Size
Another very important point to consider is that there is very limited space aboard a spaceship. For this reason, the quartz resonator needs to be as small as possible, and able to fit snugly into a limited space on the ship's control unit. One of the earliest aims of scientists preparing space-qualified quartz resonators has been to reduce their size as much as possible. This has resulted in a steady decrease in the size of resonators over the years.
6. Low Phase Noise
The phase noise of a resonator decides the accuracy of its frequency, as well as its measurement resolution. The accuracy of the resonator becomes all the more important in space for the ship's calculations. Thus, low phase noise is essential for designing a space-qualified quartz resonator.
Keeping these factors in mind while choosing a particular type of quartz resonator for your space applications will ensure that the quartz resonator is able to be put to use inside navigation controls and sensors without compromising the success of the mission.