Scam

https://docs.google.com/presentation/d/1QxC6LNOISUIK9F6m8r7OhPrHGtib-f6C0Vymi7_BcEQ/edit?usp=sharing

https://drive.google.com/drive/folders/1tu5AIPAcA6qtONqt8E98x4oS6hmYAVQp?usp=sharing

Bi-Stable Shape Memory Alloy(SMA) Space Vehicle Separation System

The Bi-stable launch separation system builds upon the 'Light-band' launch separation system of Planetary Systems Corp. but, with a novel actuating concept that is different from any existing actuation mechanism for separation mechanism in space. The linear actuation is produced using a shape memory alloy spring. Shape Memory Alloy or better known as SMA are metals that are able to recover to their pre-deformed shape when they are heated to their transformation temperature. This transformation involves generation of large amount of forces which can be used for actuation.

The whole separation system consists of multiple components that include Bi-stable SMA linear actuator ,Bi-stable Compliant element ,Bottom frame which is attached to the launch vehicle ,Top frame which is attached to the payload , Multiple Engagement Leaves ,Compression ring, Nuts and Bolts etc. The CAD model(which was designed by our team) of the assembly is represented as a image below.

The CAD model image without the top frame is shown below. This displays all the components of the system.

The novelty in our design is the linear actuator. Generally in space vehicle separation devices, pyrotechnics are used to separate the payload from the launch vehicle which involves high shock and formation of debris. The linear actuator used in our project produces very low shock. And there is no formation of debris. The actuator can be used multiple times without losing its functionality.

Working of Bi-Stable SMA linear Actuator:

An SMA spring is fixed at both the ends of a bi-stable element. A bi-stable compliant element is fixed next to the SMA element. The compliant element is attached to the compression ring through two hinges. A bi-stable element has two stable geometrical configurations. It can stay in one of the configuration without having to resist any kind of force. It can change its configuration whenever a force is applied.

When its time to actuate, the SMA spring is provided with electrical current. Through the principle of Joule heating, the SMA spring heats up and contracts upon reaching transformation temperature. This leads to the bi-stable element to change its initial stable position to its other stable position. The curved part of the element is said to have actuated. This actuation pushes the bi-stable compliant element into its other stable position. This combination of linear actuation from both the bi-stable components compresses the compression ring which frees the Engagement Rings. The Engagement Rings that were holding the the top frame, releases it. Therefore, the payload that was attached to the top frame is separated from the launch vehicle. The picture below shows the position of SMA actuator after actuation.

Picture of the SMA actuator with compliant element,

The pictures below show the top view of before and aftermath of actuation,

Before actuation

After actuation

The free ends of the SMA spring are connected to a electrical power source for the spring to heat.

Sectional View of the device,

Before Actuation:

After Actuation:

Top frame separation pics:

Before Actuation:

After Actuation:

Benefits of Bi-Stable SMA linear actuator:

• Low shock separation process, when compared to pyrotechnic separation mechanism.
• Low power requirements, when compared to a motorized linear actuator.
• Higher stroke length, which is very limited in the case of SMA actuators without bi-stable element.
• Reusable
• Easy manufacturing since it doesn't involve parts that move.
• Can be tested before using it, unlike a pyrotechnic device.
• Doesn't produce any debris.
• Compact, when compared to motorized linear actuator.

Specifications(of the SMA spring)

• SIZE: Length=12.5cm, Ring diameter=1.3 cm, thickness diameter=3.25mm
• MASS: <50gms
• FORCE GENERATED: Around 2.5-3 kN
• STROKE LENGTH PRODUCED(entire device including compliant element): ~3.5cm
• TRANSFORMATION TEMPERATURE: 100 degrees Celsius/373.15O K
• MATERIALS USED: Ni-Cu-Al SMA

What do we hope to achieve?

We hope to achieve safety, reliability and cost efficiency of deployment of small-to-mid sized satellites in the orbit. With the help of concept we developed during the weekend for the hackathon, we hope to aid shock free and cost effective separation process in space.

Tools used to develop the project:

We used CAD software(Autodesk Fusion 360) to design and develop the SMA launch separation system model.

The resources page of the challenge provided us with enough resources to kick-start our project. The boot-camp video helped us to set objectives for our project. The different methods used for separation mechanism of space components by NASA equipped us with general understanding of how our project should be. The resources page contained a research paper regarding Shape Memory Alloys(SMA) that sparked interests to use them in our project. The Planetary Systems Corps' Light-Band launch vehicle separation system provided us with enough knowledge on how existing separation mechanisms on rockets worked. The fact that bi-stable SMA linear actuators weren't used for separation mechanism made us come up with this concept.

Space agency data used:

1. https://spinoff.nasa.gov/Spinoff2020/ip_8.html
2. https://trs.jpl.nasa.gov/bitstream/handle/2014/45484/14-0701_A1b.pdf?sequence=1
3. https://ntrs.nasa.gov/api/citations/20110016488/downloads/20110016488.pdf
4. https://www.nasa.gov/mission_pages/constellation/ares/parachute_results.html
5. https://www.hq.nasa.gov/alsj/CSM12_Earth_Landing_Subsystem_pp93-98.pdf
6. https://www.youtube.com/watch?v=7ke45XZns4o&list=PL37Yhb2zout05pUjr7OoRFpTNroq_wd9f&index=16

The overall experience of the hackathon was amazing for us as a team. We learned a lot about the present technologies that exist in the field of space tech, especially the technology behind staging of launch vehicles.

1. https://www.researchgate.net/publication/304576314_Bi-stable_SMA_Actuator
2. http://www.planetarysystemscorp.com/web/wp-content/uploads/2015/09/2000785F-MkII-MLB-User-Manual.pdf
3. https://www.sciencedirect.com/science/article/pii/S2405844020314559

#hardware #launchvehicles

This project has been submitted for consideration during the Judging process.