Travelers in the Night Eps. 377 & 378: Fission Rocket & Enormous Visitor

0:00It's the 365 Days of Astronomy podcast, coming in 3, 2, 1.

0:22To get an idea of the energy involved in a rocket launch, the NASA Saturn V moon rocket, fully fueled on the launch pad, contained the chemical energy of 2,000 pounds of TNT. This old technology could carry us to Mars and back on missions that would last years. To cut the mission time, the risks, and the mass of supplies required for such a prolonged space mission, NASA is looking at alternative means of rocket propulsion. Back in the 1950s, NASA's Project Orion was a study to investigate propelling a rocket

0:58by a series of atomic bomb explosions behind the vehicle. Now a safer and more gentle way of propelling a spacecraft with nuclear fission is being studied as the result of a NASA grant to BWX Technologies. The concept is to heat liquid hydrogen using a high-temperature fission reactor furnace, which would expel the gas at a high velocity producing the rocket's thrust. The process would be about twice as efficient in terms of thrust per pound of fuel

1:32when compared to burning a hydrogen and oxygen mixture. Since it is unacceptable to release trace amounts of radioactivity in the rocket's exhaust, engineers are investigating a technique developed by NASA in which the hydrogen exhaust is burned with oxygen to produce water, which can be caught and decontaminated. Don't expect to buy a round-trip ticket on a high-speed fission-powered rocket anytime soon. However, in the long run, nuclear technology could revolutionize the exploration

2:06and colonization of our solar system. For Travelers in the Night, this is Dr. Al Grauer. Go to travelersinthenight.org program 413 for more information.

2:23Without additional data, the true nature of the rapidly northward-moving point of light my Catalina Sky survey teammate Carson Foles had just discovered would have remained a mystery. Fortunately, this new object was tracked by telescopes in both Arizona and New Mexico. These data were used to calculate its orbit around the sun, estimate its size, and give it the name 2017 UX5. When Carson first spotted this enormous 1,200-foot diameter space rock,

2:54it was more than 30 million miles away, traveling in our direction at 10.7 miles per second. Its orbit and that of the Earth's nearly intersect, and at the closest point, they are about two and one-half times the moon's distance from us apart. An asteroid the size of 2017 UX5 impacts the Earth every 76,000 years or so. According to the impact calculator developed at Purdue University and Imperial College of London,

3:25If 2017 UK5 is made of porous rock and came in at an angle of 45 degrees, it would start to break into pieces at an altitude of 41 miles, and upon reaching the surface would create a crater 2.2 miles in diameter and five-eighths of a mile deep in sedimentary rock. The results 20 miles away from impact would be that of a 6.4 Richter scale magnitude earthquake, followed by a 176 miles per hour air wind blast,

3:59which would blow down 90% of the trees and collapse wood frame buildings. Fortunately, asteroid hunters have not discovered any object like Carson's discovery with our number on it. For Travelers in the Night, this is Dr. Al Grauer. Go to travelersinthenight.org, program 414, for more information.

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4:32Cool. The 365 Days of Astronomy podcast is produced by the Planetary Science Institute. Audio post-production is by me, Richard Drumm. Project management is by Aviva Yamani. And hosting is donated by Libsyn.com. This content is released under a Creative Commons Attribution, non-commercial 4.0 international license.

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5:34we're looking forward to unraveling more stories from the universe. With every new discovery from ground-based and space-based observatories and each milestone in space exploration, we come closer to understanding the cosmos and our place within it. Until next time, let the stars guide your curiosity. We'll see you all next time. We'll see you all next time. We'll be right back.