Problem Statement:
Design a miniature satellite (CubeSat) that can identify and retrieve/re-orbit lost satellites.
Judges:
Prize: Won second place (globally)
Software used: Fusion 360
Conducted by: Autodesk
Vanguard 1 is the 4th successful satellite to be launched into space in 1958. It was designed to test the 3 stage launch vehicle, and the effects of space on satellites and its systems while in the earth's orbit.
It lost communication with earth in 1964, and remains in orbit till date, becoming the oldest human-made object in space.
Over the years, it derailed from its original orbit, slowly and increasingly deviating from its intended path. As the satellite does not have its own propulsion system, it can not correct its course.
Problem statement (detailed):
To design a CubeSat that can identify Vanguard 1, and re-orbit the satellite to its original path/or bring it back to the main ship for decommissioning.
CubeSats are miniature satellites made up of singular or multiple units of 10cm x 10cm x 10cm dimensions. These satellites have no launch capabilities and require a larger ship to transport them to space. Once in space, they are deployed to do tasks they are designed for.
CubeSats have stringent specifications about its dimensions, weight, and what can be placed inside. At its rest state, each CubeSat has to strictly conform to the outer dimensions without any protrusions.
In other words, we have to think inside the box.
On the brighter side, many commercial off-the-shelf components that can be used readily to achieve certain functionality of the satellite.
In this problem, as there is a clear problem statement and objective, the required functions of the product also become clear.
Hence, we can use Function-Behavior-Structure methodology for solving this problem.
In the FBS system, any product can be classified into three categories: function, behavior, and structure of the system. The system can be anything, such as a physical or a digital product.
The function (F) of the system is the purpose of the product.
The expected behavior (Be) of the system is the behaviors that are expected to be shown by the system based on the function.
Based on expected behavior, the structure (S) of the system is designed. This is where the tangible product is built.
The structure results in the behavior derived from structure (Bs).
For a successful product, the gap between Be and Bs has to be minimum. Reiterations in the structure are done to minimize this gap.
The problem statement becomes the requirement (R): CubeSat that can re-orbit Vanguard 1 to its original path.
From this, the function (F) can be defined as Cubesat that can translate in space, identify and secure Vanguard 1, and take it back to the original path.
Based on the above function, the following expected behaviors (Be) of the CubeSat are defined:
Assuming the rough position of Vanguard 1 is known in space, the CubeSat can be deployed near the regions of Vanguard 1. Vision-based system can be used to identify Vanguard 1.
Off-the-shelf camera component NanoCam C1U is used for this purpose.
Most of the satellites use the position of the sun to identify their alignment in space. A SunSensor can be used for this purpose, like the nanoSSOC-D60 digital SunSensor.
As the CubeSat position is known, a sensor with a lower sensing range but smaller footprint would suffice, saving valuable space in the CubeSat.
The onboard camera can also be used for this purpose- by identifying stars and constellations, the alignment of the CubeSat can be found.
This parameter controls the alignment of the CubeSat in space. Again, off the shelf components can be used for this purpose.
Favoring a fuel less solution, Magnetorquers are devices that can produce an electric field using a solenoid. The interaction between this electric field and the earth's magnetic field produces an electromagnetic force on the component. This force can be used to align the CubeSat as required.
A 3-axis ISIS Magnetorquer Board was selected for this purpose, which can perform all roll, pitch, and yaw movements.
Once we can control the roll, pitch and yaw movements, to translate in 3D space, we need a propulsion system that move and stop in at least one direction. Two parts of MPS-100 CubeSat Modular Propulsion Systems were selected for this purpose, one for acceleration and one for deceleration.
Thruster for acceleration
Reverse thruster for deceleration
A combination of solar panels and batteries are used for this purpose. The CubeSat solar panels also open to expose much more surface area to the sun and absorb more energy.
This energy is stored in a battery, and NanoPower P31u is selected for this purpose.
Solar panels that open when deployed
NanoPower P31u Battery
There has to be a module that acts as a control system for the whole CubeSat. An ISIS On Board Computer was chosen for this purpose.
The CubeSat has to contact the main ship or the ground station, and the ISIS UHF downlink/VHF uplink Full Duplex Transceiver serves this purpose. It acts as both information transmitter and receiver.
After all the above components are outlined, the mechanism of securing the Vanguard 1 has to be decided. As the function of this module is particular to this one case and is not available in the market, the mechanism has to be custom designed. Different methods of securing the Vanguard 1 were brainstormed, and finally, the following mechanism was developed.
The two arms of the gripping mechanism slide out of the CubeSat with rack and pinion mechanism. After they slide out, the same pinions are grounded with a solenoid screw, holding the pinion in place. Now, the same motors that helped the arms slide out of the CubeSat control the angular movements of the arms. This is done to save valuable space inside the components.
Gripping mechanism sliding out of the CubeSat
Grounded pinion, leading to angular control of the arms with the same motor
The gripping mechanism was specially designed to fit all the components within the CubeSat when in the rest state.
The rails (skeleton) of the CubeSat were modified to mount and support all the components inside.
Component Breakdown of Pandora
Released into the lower earth orbits by larger rockets, the CubeSat opens its solar panels to increase the surface area and capture more energy from the sun.
The CubeSat uses the onboard camera and SunSensor to identify its position in space. It uses a combination of thrusters and magnetorquers to maneuver itself.
After it locates a lost satellite, it opens the flaps and activates the grabbing mechanism.
The CubeSat locates the other satellites using the onboard camera.
It deploys the gripping mechanism by opening the flaps. The gripper moves out of the satellite by a rack and pinion mechanism.
The gripper secures the lost satellite and either places the satellite into its correct orbit or brings it back to the main station.
High resolution and photo-realistic renders were made using Fusion 360's Cloud Rendering.
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I 3D printed the models to presented in India Design Week conducted by Autodesk, in Coimbatore, India.
The following is a 1:1 scale model; the dimensions of CubeSat being 1000 millimetres in length and width.
I'll be happy to answer any
questions you have.
tejabalu15@gmail.com
+91 7674033324
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Designed by Teja Balu in
