Chaparral High (31)/Interim Report

Interim Report
http://mode.lanl.k12.nm.us/get_interim1112.php?team_id=31

Problem Definition
The first man-made object to enter the Earth’s orbit was the Soviet Union’s Sputnik 1, in 1987. Since then, mankind’s space exploration projects have filled the low-earth orbit and the geostationary earth-orbit with millions of objects and fragments (Stansbery, 2009).These objects, along with millions of naturally occurring micrometeorites, are a potential threat to future space projects and to the functional satellites in orbit. According to NASA (2010), they reach hypervelocity speeds of 22,000 mph, therefore even an object with a diameter of 1 to 10 cm can cause catastrophic damage to spacecraft due to the force of impact. Our goal for this project is to create a simulation through NetLogo that will allow us to predict possible outcomes of the continuing growth of space junk. Through this model we will be able to determine whether or not certain variables can have positive results in controlling this growth. For example, we will determine the possible scenarios that can occur in the earth’s orbit after a certain number of years. Fragments in orbit eventually are pulled into the atmosphere due to the gravitational pull of Earth or fall out of Earth’s orbit because of its distance from Earth (Fleur, 2011). Will enough objects fall into the atmosphere to prevent chain reactions of collisions, or is the debris multiplying faster than it is being destroyed?

Problem Solution
The NetLogo simulation will include several variables to best illustrate the real life events in Earth’s orbit today. The objects, or debris, will be in orbit around the Earth’s atmosphere. The model generates different random number of debris with different random sizes. These generated random numbers are produced with regard to facts about number of debris and their sizes, which were found in the research phase. The objects will be affected by Earth’s gravitational pull, therefore slowly getting closer or farther from the atmosphere. The objects will also collide with each other, in turn creating smaller objects that will be differentiated by color. Satellites will also be a different color in order to determine the number of satellites that could possibly be damaged or at least impacted, and how much more debris impact with those satellites will cause. Through this model we will be able to view the possible scenarios that can occur.

Progress to Date
At this point, we have a NetLogo model which has the primary components of our intended final simulation. In the model, turtles represent objects, not defined yet into satellites or sizes, which move in circular orbits around earth’s atmosphere at different speeds. This was done by asking the turtles to arc forward a distance, then move at random speeds, at random distance from origin. By using an equation for a circle, we created the “atmosphere” which the turtles slowly drift into. This is possible by asking the turtles to set radius to -.5, if their current radius is greater than 5 (radius 5 is the atmosphere). The turtles can also be too far from the atmosphere. If the turtle’s radius is greater than 10, they will drift away from the atmosphere by increasing the distance by .5 and fall out of orbit if the radius is 15, which causes the turtle to die. When we run the model, the space objects begin their orbits. Some objects fall into the atmosphere, causing them to disintegrate, and some are leaving Earth’s orbit completely.

Expected Results
We expect this model to allow the user to visualize the amount of space debris in orbit, and the chain reactions that would cause. The results will show us the percentage of debris that stays in orbit. We will also see how speed affects force of impact, and how much more debris will be created. Maybe the impacts will slowly have less force and therefore will eventually stop. On the other hand, collisions might cause more collisions and more debris to gain speed and cause greater damage.

Introduction
Hello,

My name is Dennis Trujillo a Physics and Mechanical Engineering student at New Mexico State University, and previous intern at Los Alamos National Labs. See the biography listed on my User Page. If there are any questions relative toward your project feel free to contact me at dptru10@nmsu.edu.

Progress
From the progress listed in the report, it looks like you have a good start overall. A minimal environment has been developed in which you can add further turtles defined for certain purposes. Adding types to these turtles and defining the physics which accounts for some of the phenomena you're observing would be the next step. You mentioned a boundary layer of sorts above which there is a minimal safe environment for the turtles and where at extremes turtles are removed. Does this represent a turtle entering into the atmosphere or leaving an effective range of the Earth's gravitational field? If there are questions relative to the physical aspects of individual particle interactions (i.e. object impacting other object) feel free to ask.

Mentors
From your page it seems you don't have a listed mentor, if necessary the Challenge might be able to recommend someone who might be of help in terms of modelling your particular problem or the physics in occurrence (consult@challenge.nm.org). Likewise I would be happy to provide recommendations.

Model
The existing model provides a good platform for adding additional objects and physics to the environment you have designed; further research relative to the physics behind your particular project is encouraged as I would like to see an implementation of simple momentum and energy considerations applied to a large number of particles. Likewise if able it would be great to statistics relative to number of turtles in existence, collisions between specific types of objects, and mean velocity of the objects in consideration.