Let It Go (Without A Bang)

Background

Letting things go in space, or separating spacecraft parts is often a violent, high-shock event. Spacecraft include a lot of release devices onboard to allow the spacecraft to separate from the rocket, release or expand a parachute for entry, or enable deployables to open up in space. When we need to separate things in space, the typical approach is to use pyrotechnic devices. These include reefing line cutters for parachutes, bolt cutters to separate heat shields and launch ring adapters, and cable cutters. However, pyrotechnic devices require extra safety protocols, can only be used once, and create large impact loads (or shock), up to thousands of Gs.

Other solutions include frangibolts, where a shape memory alloy is used to break a specially designed bolt. However, these devices also create a high shock when the bolt is broken

The other issue with pyrotechnic devices and frangibolts, is that they have parts which need to be replaced after each actuation. That means you can never test the same piece of hardware you are going to operate in space. If release devices were resettable, meaning no parts would break during actuation and need to be replaced, they could be tested on the ground prior to flight.

Objectives

Your challenge is to design a mechanical separation device that can cut a parachute reefing line, a bolt for an adapter ring, or a cable, or release two parts from each other smoothly in space without pyrotechnics. The device must work quickly and operate without an impact and should be different from existing methods. In addition,

• Your device should survive temperatures of -50C to +80C (heaters can be used to keep the device warm).
• Your device should operate between 0C to +40C (once again, heaters can be used).
• No net debris should be allowed to escape. Everything needs to be captured or attached to one static body or the other. If debris escaped, it would create space junk.
• Provide the minimum volume and mass your device requires. The device should be smaller than a cylinder that is less than 15cm long, by 2cm in diameter, and weigh less than 1 kg.
• Tell us how many Newtons of force your device can hold together (during launch) or push apart.
• Try to estimate the reliability of your device. It should work 99.5% of the time or better.

Potential Considerations

As you develop your concept, you may (but are not required to) consider the following:

• Tips for a great design:
  • The more preload (the force holding two objects together) in the item your device can cut, the better.
  • Your device does not need to be electrically driven, but if it does use electricity, it should not consume more than 20W.
  • The smaller the device the better, as this means we could use it for Small Satellites.
• Additional Desired/Bonus Features:
  • Your device is fully resettable and does not require replacement parts after actuation.
  • It’s beneficial if your device is smaller than a AAA battery, a cylinder that is 44 mm long by 10 mm in diameter.

For data and resources related to this challenge, refer to the Resources tab at the top of the page. More resources may be added before the hackathon begins.

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