Welcome to the second action project for my STEAM class, Frontiers. This class is about exploration. During this second unit, my class focused on space exploration. We went on a field experience at the Adler Planetarium and learned about the timeline of the universe. We also spoke virtually with a graduate student named An Li who is focusing on getting her Ph.D. in space studies. For my action project, I had to write a research paper about a challenge that we face during space exploration. I choose to focus on space debris and how this affects space exploration.
Space Debris: the litter in Earth's orbit
CBS News. ¨Space Junk.¨
The growing population of space debris has made it increasingly difficult to execute space missions. In response to this problem, there is a global consensus that space activities need to be carefully monitored to reduce the risk of adding to the current amount of debris within Earth's orbit. There is currently no global collective effort for current space debris. Many countries worry that over time, the increasing amount of space debris will hinder any further exploration past our earth's lower orbit. Some countries are regulating space missions to stop the amount of debris that is released further into our earth's orbit. Many countries are also creating programs to track space debris. By tracking debris, we can better plan missions and avoid hazardous collisions with space debris which delays and hinders space exploration. Scientists have many ideas on how to mitigate space debris but are worried that these options may be too expensive or end up causing more debris as a result of their deployment.
Orbital space debris has been identified as a root cause of many space exploration anomalies. There is a formula to help predict the collision with trackable space debris. Öpik’s formula for the probability of collision is applied to the analysis of the collision risk against space debris in Low-Earth Orbit (LEO) and Medium Earth Orbit. (Rossi and Valsecchi). This helps scientists and engineers when launching things into the orbit of our earth. While within earth's gravitational pull, an object is at serious risk of getting hit by space debris. This could be very damaging. There are more than 600,000 trackable pieces of space debris but so many other pieces are too small to be tracked. Spacecraft bodies can be protected by shields but their solar panels are constantly hit by small pieces and fragments of space debris, too small to be tracked from Earth. Over time, thousands of these small impacts deteriorate the exposed surfaces of the spacecraft.
The challenge of avoiding space debris in space exploration has been recognized at an international level. The United Nations Office for Outer Space Affairs published the Space Debris Mitigation Guidelines in 2007, which include the need to limit the chance of an accidental space collision in orbit. Every time a satellite swerves to avoid a collision, resources are lost. For instance, a satellite has to take time to chart a path to avoid this debris. It then wastes extra fuel straying from its original course in order to avoid a collision. In order to make up for the wasted fuel, the satellite shuts down and loses time recording data.
There is no organized program for removing existing space debris. (Kaplan). Many scientists have thought up ways to mitigate this problem, but none are currently operational. Actively removing debris is a challenge. Removing current debris is costly and consumes many resources. When creating a mitigation plan for space debris, scientists and governments must weigh all of the options in case their existing plan fails and adds to the existing amount of space debris. The removal of objects from high-density areas in orbit and objects with long orbital lifetimes may be necessary in order to stabilize the current population of space debris. This must begin now, as ESA’s internal studies show that continuous removal actions starting in 2060 would be 25% less effective in comparison to the immediate start of space debris removal. (See graph above).
A great way moving forward, to design satellites in order to help reduce space debris, is to design them for end-of-life disposal. This means that after 25 years in service, a satellite will automatically trend towards the earth and land back on earth, or travel further into space and exit earth's orbit. Another great way to design a satellite to remove itself and reduce debris is to design it for passivation and demise. Passivation means that once the satellite is out of service, it will completely deplete all fuel or energy to prevent accidental post-mission explosions. Demise means that the satellite will be built to fragment in a certain way upon reentering so as to not harm people or property on earth.
Other space agencies around the world are looking at more futuristic ways to reduce the current amount of space debris that exists in our orbit. One idea is to create satellites with drag sails. Doing this will help guide the satellites back down to earth post-mission and declutter space. Another idea scientists had where to send a spacecraft that would have a giant net attached to it. The spacecraft would drag this net through Earth's orbit and collect small pieces of space debris. Think of it as space fishing! Many of these ideas are still in the design process, as scientists need to figure out how to create a spacecraft that won't possibly cause the amount of space debris as it is trying to clean up the space debris.
Space may seem vast, but the orbits around Earth in which satellites reside are a limited natural resource. Accidental collisions, explosions, and even the intentional destruction of satellites have created millions of debris fragments, which, orbiting at high speed, can damage or destroy any functioning spacecraft that crosses their path. If we wish to continue space exploration, we must create solutions that reduce space debris and create ways to realistically clean our earth's orbit.
Sources:
Rossi, A., and G. B. Valsecchi. “Collision Risk against Space Debris in Earth Orbits - Celestial Mechanics and Dynamical Astronomy.” SpringerLink, link.springer.com, 15 Aug. 2006, https://link.springer.com/article/10.1007/s10569-006-9028-7.
“A 1 Cm Space Debris Impact onto the Sentinel-1A Solar Array - ScienceDirect.” A 1 Cm Space Debris Impact onto the Sentinel-1A Solar Array - ScienceDirect, www.sciencedirect.com, 17 May 2017, https://www.sciencedirect.com/science/article/abs/pii/S0094576517304125.
“Real-Time Space Debris Monitoring with EISCAT - ScienceDirect.” Real-Time Space Debris Monitoring with EISCAT - ScienceDirect, www.sciencedirect.com, 13 Apr. 2005, https://www.sciencedirect.com/science/article/abs/pii/S0273117705003194.
“Long Term Evolution of the Space Debris Population - ScienceDirect.” Long Term Evolution of the Space Debris Population - ScienceDirect, www.sciencedirect.com, 6 May 1999, https://www.sciencedirect.com/science/article/abs/pii/S0273117797000227.
“Survey of Space Debris Reduction Methods | AIAA SPACE 2009 Conference & Exposition.” AIAA SPACE Forum, arc.aiaa.org, 14 June 2012, https://arc.aiaa.org/doi/abs/10.2514/6.2009-6619.
Blog Conclusion:
I enjoyed completing this project. I have a great interest in space, so researching further into this topic was really exciting for me. I believe I could have done a better job in making a personal connection to the research. I also could have managed my time with this project better, as I did not get a prep worksheet in on time to my teacher for feedback.
Comments
Post a Comment