Trash X

https://drive.google.com/drive/folders/1HL2fyluEMckH273y7LAf64v-5SdVePrD?usp=sharing

http://trashx.earth/

Trash-X solution consists of three main stages

·      Tracking

·      Application

·      Cleaning

1.Tracking of space debris using Laser

Introduction:

The technology developed by Trash-X consist with 3 high performance Laser emitting satellites at a fixed position 36000 kilometers above the Earth which are in contact with 3 ground station radars which are also emitting high performance laser towards the satellites.

It has been experimentally proven Lasers have the potential to pinpoint small objects in orbit with centimeter-level precision and 3D mapping using Laser is more efficient and accurate.

But until now we have been using this technology only in fixed radars on earth to map the space, but Trash-X has developed a Topology to place Laser Scanners on three Satellites orbiting around earth in GSO to track space debris together with the existing ground radars.

This allows us to get real time 3D map of space debris around earth in each and every part above Earth with high accuracy and a full 360 degree view of the debris can be obtained. But in the existing mapping systems the fixed radars on earth can only perform Beam Park Experiments (a radar beam is kept in a fixed direction with respect to the Earth, while objects passing through the beam are tracked) In this type of tracking only some debris that pass through the beam can be tracked and only one side of the Debry can be mapped (the side of the debris that faces the beam) and there is more chance of losing track of lot of debris, but the topology developed by Trash-X allows real time mapping of each and every minute object around earth with high accuracy.

This not only allows us to track debris, but also to get more information regarding the Debris such as,

·      Possibilities of collisions between debris or other working satellites by tracking the relative velocities of debris

·      Categorizing debris as sharp debris, explosive debris, fragile debris and etc... Thereby, calculating the high-risk debris and danger zones.

·      Current position, angle and velocity of the Debry

·      Shape and material medium of the Debry

Topology:

Trash-X Debris Tracking system will use three satellites placed in Geostationary orbit with 3 laser emitting radars on earth to get real-time mapping of space debris.

Three satellites are placed in a proper constellation above Asia, Europe and America in a fixed position for efficient tracking using Lasers.

Each satellite will cover 1/3rd of LEO (120 degrees view) and this will require 3 satellites to coverup debris around the Earth.

These 3 satellites will emit high-performance laser towards the earth and the 3 radars too will emit high-performance lasers towards the satellites and thereby, almost all space debris (especially the tiny space debris) can be tracked by both the laser beams with a 360deg view data.

These three relay satellites will have permeant radio contact with a ground stations (One in Asia, in America and Europe) to deliver the tracking data and information of Space debris to Earth real-time.

The collective data from satellite and earth radars will be overlapped to get more accurate data of the Debry regarding its exact position, orbital velocity, and orbit.

The collective data makes the information more accurate and reliable because the error percentage is at a very less rate.

Such data will be processed further to obtain an accurate 3D map of the debris and 3D structure of each and every Debry if required.

Position of Satellites in GEO

Tracking System and transmission of data

Topology Simulation - https://drive.google.com/file/d/10-ep9ySwEeQsRUcGwz-UTk2Uaq5cTUFj/view?usp=sharing

now the biggest question is – How can lasers emitted in opposite directions be used for mapping?

Its obvious that we can’t distinguish incident laser and reflected laser from a beam if both the laser editors are placed in opposite direction!

So, to solve that problem Trash-X will use synchronous emitters in satellite and radar.

When satellite laser emitter is ON the radar laser editor is OFF and vise versa.

The time gap between the ON and OFF mode can be calculayed ats follows

Speed of Laser in vacuum (C) = 3 × 10^8 ms^-1

Distance between ground radar to Satellite in Geostationary Orbit (HGEO) = 35 786 000 m

Time taken for one laser beam to reach satellite and return back 

All three satellites and radars will have an inbuilt atomic clock to command the laser emitter to ON and OFF after every 0.2385733333 s. That means all radars will emit laser for 0.2385733333 s and OFF the laser emitter, and at that exact time of OFF command, satellites will ON it’s Laser emitters for 0.2385733333 s and during this time earth radars will not accept the received laser from satellite emitter and after 0.2385733333 s again radars will command ON and this process continues.

By this we can avoid the interruption of incident and reflected laser beams

Tracking process:

This tracking method will use LiDAR which determines distance measurements by beaming a laser at an object and measuring the time it takes for the reflected light to bounce back to a receiver built in Satellite and radar.

The satellite and radar will use 2D planar laser scanner to scan the debris and scanned data from satellite will be compressed the and transmit it to the Ground Station which has permanent radio contact with these satellites.

Ground Radars will also emit lasar as mentioned before in a synchronous manner with satellite and process the combined data from satellite and radar for more accurate information on 360deg view of Debry, its velocity , orbital path,etc…

Ground station will encoder data by 3D mapping system.

The 3D mapping system is based on rotating 2D planar laser in satellite and fixed beam park experiment on ground radars. But for a continuous mapping system, the challenge is that the range measurements are received at different times when the 3D LiDAR is moving relative to the Debry, which will result in big distortion of the local 3D point cloud. As a result, the errors in motion estimation can cause misregistration of the resulting point cloud. In order to continuously estimate the trajectory of the sensor, we first extract feature points from the local point cloud and then estimate the transformation between current frame to local map to get the LiDAR odometry. After that, we use the estimated motion to remove the distortion of the local point cloud and then register the undistorted local point cloud to the global point cloud to get accurate global map. Finally, we prepare a coarse-to-fine graph optimization method to minimize the global drift.

The software of the whole 3D mapping system is composed of two parts

·      low-level motion control

·      high-level reconstruction.

The low-level motion control module is responsible for controlling the 2D laser scanner rotating at a constant speed in satellite and reading and sending the encoder data. The high-level reconstruction module is responsible for receiving the scanning data and encoder data and then estimating the motion of the sensor relative to the Debry and registering the received point cloud into a 3D map.

Separate angle encoder system must be integrated to the main system to determine the angle of Debry in relative to the satellite 

This process will finally output a Realtime accurate 3D map of space debris.

We have developed a sample interface of how the final output will be like and the details of the interface are attached at the end 

Flowchart diagram of the process

Advantages of this system

·      Possible for tracking tiny minute debris due to combined tracking system by ground radar and satellite with high power lasers.

·      Able to obtain Realtime information about collisions between debris and working satellites to perform collisions avoidance manure

·      Possible to make Realtime 360deg view of debris and even working satellites and ISS

·      Obtain information on the shape and material medium of the Debry thereby categorizing debris according to their shape and material medium (Sharp Debris , explosive debris, Fragile Debris ,etc…)

·      This system can even be used to scan and make 3D map of other working satellites and ISS thereby can obtain more accurate information regarding the cracks in the outer shields and depressions in the working parts of them due to time.

·      This helps us to study the more about the gravitational field around earth by studying the orbital paths of debris as there are huge amount of debris around earth

2.Trash-X Application

We have developed a web-based application to view the current space debris in orbit and also the satellites in orbit. (This is only a demo of the application and it consist of Debris and satellite data from esri ) We will be able to use the data from Trash-X satellites and ground radars ones after the tracking process begins using the topology mentioned above.

The application consists of user-friendly interface making any individual to get easy access and data regarding the debris and satellite flying over him!

User friendly interface of Trash-X application

We have classified the information on both debris and satellites under following categories

·       Country that the Debry belongs to

·       Type – Junk , Not junk , Sharp Debris, Exploisve Debris , Fragile debris

·       Size – All, Small , Medium , Large

·       Launch date

·       Orbit period

·       Inclination

·       Apogee

·       Perigee

Classifications of debris and satellites

Satellite description and ephemeris are sourced from space-tracker.org. The satellite is JavaScript library is used to convert the TLE for each satellite into a geographic location

By using this application one can clearly see the satellites and debris together there by collisions between working satellites are debris can be calculated and avoided.

Debris (junk) map

Satellites map

This application allows the user to get the orbit of the Debry and satellite and also a short information about that specific Debry in the left hand side of the screen (Information is from NASA and N2YO) by simply clicking the Debry

Orbit of the Debry

Information panel

This application will be much usefull for anyone who is seeking for location of debris and a short information about it. Team Trash-X has also planned to further modify this demo application with more features such as reach 3D view of each debry and satellite, exact altitude of the debry and also real time collision prediction alert.

3.Cleaning Process of small space debris

As we know there are millions of small pieces of space debris ranging in size between 1 cm and 10 cm revolving around Earth on Low Earth Orbit and above. These small pieces could create huge disasters by colliding with the active satellites revolving around earth and also with future missions to space. Therefore, so many methods to remove these space debris has been proposed so far.

Since we have already working on developing a method to track down these space debris, here we present our own solutions to collect and remove them from the orbit.

Collecting the Space Debris

Since we are aware that the destruction caused by small pieces can be very immense than the destruction caused by the large space debris since they don’t get detected and move freely like scattered pieces, it is mandatory to take actions immediately to remove those minute particles.

Here we have come up with a satellite model combined with a collector (a cylindrical model which collects the minute space debris) which has the shape of a space shuttle.

1.    Control Unit

The control unit will carry the collector attached with it, along with a 360 degree rotatable camera which could trace the path of minute space debris in any angle. Furthermore, the scanners, signals indicators, thrusters and solar panels along with antennas are fixed to the main control unit of this whole system.

2.    Collector

Collector is designed in the shape of a rocket which has a nose cone, cylindrical body and thrusters at the end. Here we use the technology of electromagnetism to attract the minute space debris which are the parts of non-functioning satellites and space missions. Satellite will make its way towards the certain debris which was tracked to collect it inside the collector. Once it is very closer enough, the electromagnetism will be activated while the nose cone of the cylinder is opened through which the debris will enter the collector. Electromagnetic action will only be turned on if it is in the range to collect the debris and it will be turned off when it is not in use to avoid the attraction of debris on the outer surface of the collector as the stronger magnetic field is created for a greater efficiency.

This process will continue till the collector is fully filled and once it is completely filled, the collector can be ejected from the control unit for a unique disposal method. We have two solutions to perfectly dispose this waste without causing pollution to environment in a large scale.

Solution # 01:- Collector Flight Method

This method uses the technology of space shuttle reentry to safely pass the atmosphere and land on Earth surface. For this, high level- accuracy is used through controlled reentry where the collector will be ejected from control unit, adjust its path towards Earth and take its flight to enter the atmosphere. This maneuver is done by entering the atmosphere with a steep angle so that it ensures the fallout of the debris within a relatively small area. Since the common practice is to enter the atmosphere with an angle of -1.5° and target to fall within the South Pacific Ocean Uninhabited Area (SPOUA), the same way will be followed to reduce any kind of casualty risk.

Solution # 02:- Cargo Replacer Method

This method will help us to make a better usage out of Cargo Spacecraft since they mostly carry wastes back to earth. Our solution is to place the ejected collector into the Cargo Spacecraft on their way back home. Thrusters of the collector will be used to adjust its travelling path and reach the spacecraft and place itself inside it.

Advantages of These Methods of Disposal

1.    Environment pollution will be reduced to a greater extent

We are aware about the environment pollution caused due to burning down the reentry of space debris which includes air pollution, depletion of ozone layer, marine pollution and etc.

2.    Casualty risk can be reduced to nearly zero

Larger debris, especially debris made of high-melting-point materials such as titanium or stainless steel, however, may survive partially or in full to reach the ground when they are burnt through air drag technique. But this method could help you rescue the debris safely and reuse the metals.

3.    No addition of chemicals

When defunct satellites burn in the atmosphere, they leave behind chemicals that could damage the ozone layer and affect how much light Earth absorbs. The burning of aluminum is known to produce aluminum oxide, also known as alumina, which can trigger further unexplored side effects. Alumina reflects light at certain wavelengths and if you dump enough alumina into the atmosphere, you are going to create scattering and eventually change the albedo of the planet. But this method has no way to leak any chemicals.

We used most of the details provided by NASA for making this project.

Also, we used some other information from Esri which is a Geographical Information Company , The debris cleaning system developed by ESA inspired us to make another cleaning system that can be used to capture space debris.

Information regarding debries and satellite mapping was obtained from ESRI

NASA Space Apps has been the Gateway to showcase our long term innovative idea to the whole world. We have been thinking about the destructions caused by space debris to the satellites, space missions and also to the planet Earth in general. It has always been a question on how to track them down and clean these debris of small size. We were so excited to see the exact challenge we were looking for on Space Apps Challenge Tab to create our own innovative solution.

It has been an adventurous ride to research, educate ourselves and come up with a system as a solution for the unsolved problem of space debris and its hazardous collision. We learnt so much about Space Debris, how much of an impact a minute piece could cause to a huge mission, usage of laser technology in space and etc. Apart from that we also developed our skills on problem solving, coming up with better ideas which could have a very less negative impact to the environment, team work, leadership skills, scientific and logical thinking.

Firstly, we identified the problem and the hypothetical solutions which have been proposed by different parties. Then we did a research on their positive and long term negative impacts. This helped us to build our own model which is a system of tracking and collecting the Space Debris for a better disposal method. Thereafter, we divided the task among the members based on each player's interest and passion which helped us for the efficient performance.

Since this is a challenge in whole, we had to break the barriers and develop an effective concept without any minor issue. Therefore, we had to find the loopholes and resolve setbacks by contacting the mentors who have more experience with major projects.

In this moment, we are obliged to pay our sincere gratitude to the local lead of Colombo Space Apps Mr. Anupa Kulathunga and our mentors Mr. Lahiru Udara, Ms. Udeni Kalpana, Mr. Sachitha Weerakkodi and Mr. Dilshan for lending us their huge support when we needed it the most. Without them, this project would have been incomplete with so many unfound loopholes. It is our immense pleasure to be a part of this legendary challenge and again all credits goes to the Organizing Committee of NASA Space Apps Challenge without whom our ideas would have been left unsaid to the world. Their hard work and dedication behind the screen has played a huge role in helping us to unveil the skills, talents and ideas hidden inside us. We thank you all wholeheartedly for not only creating such an ideal place to express our ideas but also for helping us in every single step of this challenge.

"We will continue to explore and invent with the lessons learned from NASA Space Apps Challenge 2021"

https://www.universetoday.com/109147/how-a-laser-appears-to-move-faster-than-light-and-why-it-really-isnt/

https://www.spacelegalissues.com/marine-pollution-caused-by-space-debris/

https://www.esa.int/Safety_Security/Space_Debris/Reentry_and_collision_avoidance

https://www.esa.int/Safety_Security/Space_Debris/Reentry_and_collision_avoidance

https://blogs.esa.int/cleanspace/2018/11/16/basics-about-controlled-and-semi-controlled-reentry/

https://blogs.esa.int/cleanspace/2017/03/02/how-do-materials-behave-during-atmospheric-re-entry/

https://cordis.europa.eu/article/id/122472-first-satellite-able-to-reenter-the-atmosphere-in-a-controlled-way-just-launched

https://orbitaldebris.jsc.nasa.gov/reentry/

https://www.space.com/starlink-satellite-reentry-ozone-depletion-atmosphere

#spacedebris #cleanspace #trashx #satellites

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