Lunch & Learn- Hazards from Space: Space Debris and Asteroids
- What
- Lunch & Learn- Hazards from Space: Space Debris and Asteroids
- When
- 5/2/2014, 12:24 PM – 2:00 PM
- Where
- MPR (Multipurpose Room)
Meet Nahum Melamed who works for the Aerospace Corporation in Planetary Defense and deflects Asteroids for a living!
The presentation talks about two types of near earth space objects: manmade objects such as space debris, and naturally occurring objects such as asteroids and comets. The presentation begins by answering several questions related to space debris: Why do we go to space? How do we get there? What can we do while being in space? What is manmade space junk? Where it is found? What concern does it pose? How do we get rid of it? What happens when it reenters the atmosphere? Does any survive and hit the ground? During the presentation, actual space debris samples will be passed around for the audience to touch.
The presentation continues with background and a historical overview on the impact threat
posed by Near Earth Objects (NEO) such as asteroids and comets. Special issues and unique concerns associated with NEOs are explained, and a brief description is given on the origin and structure of the Solar System, including the planets, moons and asteroids. The contrast between extensive impact cratering evidence found on some planets and moons but not so much on Earth is brought to notice. Several examples of known Earth impact events are shown, including Meteor Crater in Arizona, and the Tunguska event in 1908 in Russia. The 15 February 2013 asteroid explosion event over the Russian city of Chelyabinsk is also described.
The basic elements of planetary defense are described next: detection, decition to act, and
deflection or destruction of the asteroid, if necessary. An illustrated asteroid discovery process is shown through a time series of night sky photos with a object moving relative to the fixed stars.
Deflection of an asteroid away from a collision course with Earth is achieved by applying a
small velocity change to the object’s trajectory well before Earth impact time. One method for doing this is by smashing a heavy, fast-moving spacecraft, called a “kinetic impactor,” into the asteroid.
The last part of the session is a hands-on, interactive demonstration of a physics-based asteroid deflection simulator that was developed at The Aerospace Corporation for NASA. The tool uses a set of fictitious asteroids of varying orbital characteristics, all designed to impact with Earth. The objective is to design a mission using today’s launch vehicles to deflect the asteroid away from an Earth impact using a kinetic impactor spacecraft. Several scenarios are examined by varying asteroid sizes and the length of time from object detection to Earth impact. No technical background is necessary to try the simulation tool and extract useful insight into the challenges involved with deflection of asteroids.