Harold Kaufman, an engineer at the N.A.S.A. ... Xenon is chemically inert and is approximately four times heavier than air. ... This requires the use of chemical thrusters, like liquid-fuel rockets, to help them exit the atmosphere. ... This continuous thrust allows for a shorter travel time in comparison to chemical propelled engines that give a large boost in the beginning and then rely on the ship to coast through space for the rest of the time. ... The size and mass of the engine and resulting spacecraft is considerably less than those utilizing chemical propulsion engines. ...

• Word Count: 1766
• Approx Pages: 7
• Grade Level: High School

One is the trace contaminant control system and it detects trace odors, chemical leaks, and spills. ... These fluids will help engineers to build earthquake-resistant buildings, increase productivity in materials processing, and performance of power generating sources. ...

• Word Count: 1616
• Approx Pages: 6
• Grade Level: High School