Monolith reinforces its M1 engine with another innovation to tackle the extreme forces and temperatures at play during space exploration. The engine mount was developed to further insulate its beating mechanical heart and protect it well beyond its certified 555g impact resistance.

Fast forward to the present day and it is hard to imagine a world without a unified time system. Coordinated Universal Time (UTC) is the primary time standard on earth. In recent years, we have also begun utilizing this time standard for mission planning on the International Space Station (ISS). This poses a new yet familiar inquiry: What happens when we establish a base on Mars where we are no longer confined by a 24-hour Earth day? Will we convert time between planetary time zones or establish a new unified standard? As we journey towards a multiplanetary civilization we will need to redefine standards for visualizing time.

Accuracy of a Watch

The balance wheel is the beating heart of a mechanical watch. This key component is responsible for controlling the frequency and accuracy of a watch’s engine. 

When a watch undergoes an impact, the balance wheel’s motion is temporarily disrupted leading to a loss of accuracy in timekeeping. This means that no matter how accurate an engine is made to perform, it is ultimately still susceptible to the external elements of daily wear. Heavy impacts not only affect accuracy but can cause damage to the dial feet, display hands, and the engine gears themselves.

Companies have developed a variety of anti shock systems for the engine as well as higher frequency balance wheels to minimize disruptions. They have also developed testing regulations such as COSC to guarantee the accuracy of a watch, but these metrics only show how it performs in sterile conditions and not representative of the environments they are subjected to in the real world.

Durability in Space

Traditionally, engines are mounted directly to the case itself or a metal movement holder which is then clamped to the case. These rigid mounts ensure that the engine is secure, but transfers all the energy of an impact directly to the engine and in some cases even amplifies it. A direct metal to metal contact also means that external thermal conditions are more easily transferred to the beating heart of a watch.

As we visited in previous articles, vibration, impact and extreme temps are all key conditions to consider when developing tools for aerospace. From the original EVA tests outlined by NASA for the Apollo missions:

- Six shocks of 40g each, in six different directions, with each shock lasting 11 milliseconds.‍

- The test item shall be accelerated linearly from 1g to 7.25g within 333 seconds, along an axis parallel to the longitudinal spacecraft axis.

- Three cycles of 30 minutes (lateral, horizontal, vertical, the frequency varying from 5 to 2000 cps and back to 5 cps in 15 minutes. Average acceleration per impulse must be at least 8.8g.

These rigorous tests represent just some of the many forces experienced during takeoff. Impact resistance also becomes a factor when someone is away from their home planet's local service center. With current space missions often lasting 6 months or more, A damaged tool from everyday bumps can mean it is out of service until the mission is complete.

The Engine Mount

The engine is arguably the most mission critical system of the entire tool. While it is already designed to withstand the harsh temperatures of space and up to 555g of impact, redundancies are key in space exploration. Traditionally, watch engines are mounted to the case or a movement holder meaning that any external impact energy is transferred directly to the micromechanics and can cause severe damage. To remedy this brands have come up with a variety of solutions to provide better impact resistance.

For example MB&Fs EVO series using a spring type engine mount. This system however mainly provides resistance in the z direction (up and down) as any lateral movements are still mostly rigid.

Another innovation is Richard Mille’s RM27-04 which uses a braided steel cable suspension system. This aids in impact resistance (primarily in the z axis), and makes the watch ultralight at ~30 grams (Monolith prototypes currently weighing in at 34 grams)

The last known approach uses rubber-like materials to make the engine mount itself. This is most commonly seen in G shock systems such as aGEL bumpers or in some cases, brands making the entire engine mount out of visco elastics which deforms under stress and returns to shape slowly.

This is where we started our explorations, however we quickly learned that while viscoelastics are a great solution for earth bound activities, the extreme temperatures of space can cause the material properties to change, making them brittle in extreme cold and lose shape in extreme heat. We then explored harder dampening materials such as PEEK and PTFE commonly used in aerospace applications for their temperature stability. We reached out to Orion AM as the leaders in PEEK 3d printing for aerospace. While the printing quality was fantastic, we quickly learned that any engine mount made of these materials would cause issues down the road. Each time there was an impact, the mount would deform as intended, but over time this deformation caused the engine to dig in, getting things out of alignment and ultimately rattling within the chassis.

To remedy this we developed a solid CNC machined aluminum engine mount combined with custom Silicone O-rings to dampen impacts in all directions. This provides a rigid frame to hold the engine, while also creating a highly effective vibration dampening system.

The only contact to the chassis comes from these Silicone O-rings which will perform even in the most extreme temperatures of space. This solution has travel limiters built directly into the chassis and caseback to provide the engine with up to 0.3mm travel deceleration in all directions. This travel limiting system also provides an additional air insulation layer between the outside world, limiting direct thermal conductivity to the engine. This engine mount system also provides room for the metals to expand and contract uniformly from extreme temperatures without causing strain on key components. Less material (air pocket) also means a lighter overall construction.

The engine mount alone significantly increases the overall impact and temperature resistance the watch can handle. Although we wish you a smooth landing and moderate temperatures on your next trip to mars, know that your Monolith will stay precise amongst all the bumps of the journey and whatever the weather.

Our next step is working through all the original EVA testing protocols NASA set out during the Apollo missions to certify the device, and set new quantifiable standards it will be able to withstand.