Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps.643 & 644: Space Vehicles & Tracking Meteoroids

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s two stroy:

  • SpaceX is developing a new (methalox) engine called Raptor.
  • Many meteoroids come from comets which have passed near Earth as long as 4000 years ago.

Bio: Dr. Al Grauer is currently an observing member of the Catalina Sky Survey Team at the University of Arizona.  This group has discovered nearly half of the Earth approaching objects known to exist. He received a PhD in Physics in 1971 and has been an observational Astronomer for 43 years. He retired as a University Professor after 39 years of interacting with students. He has conducted research projects using telescopes in Arizona, Chile, Australia, Hawaii, Louisiana, and Georgia with funding from NSF and NASA.

He is noted as Co-discoverer of comet P/2010 TO20 Linear-Grauer, Discoverer of comet C/2009 U5 Grauer and has asteroid 18871 Grauer named for him.

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643: Space Vehicles

According to Newton’s third law a rocket engine generates its thrust by expelling mass rearward.   Using chemical rocket engines the Saturn V took men to the Moon using kerosene and liquid oxygen while the Space Shuttle was launched into orbit with solid fuel boosters. Currently, SpaceX’s Falcon 9  uses Merlin engines which operate with kerosene and liquid oxygen as fuel. SpaceX is developing a new engine called Raptor. It will use liquid methane and liquid oxygen for fuel to become the most efficient rocket engine ever built.  In fact the Raptor will generate twice the lifting thrust of it’s predecessor 

the Merlin engine.  Each SpaceX Starship Spacecraft will fly with 6 Raptor engines in addition to 35 Raptor engines on the Super Heavy rocket which is part of it’s launch system.  These powerful rockets are designed to be reused 1,000 times and be able to transport 100 people into space, crews to the Moon in 2023, and crews to Mars at a future date.  Even with these most powerful chemical rockets it will take 7 to 9 months for a crew to reach Mars.  Three companies are being funded by the US Defense Advanced Research Projects Agency to develop a rocket engine where hydrogen gas is heated by passing through a nuclear fission reactor before it escapes through rocket’s nozzle.  Such a space ship will be capable of crewed flights from Earth orbit to Mars orbit in about 3 months.  By cutting the flight time to half or less the weight savings in food, fuel, and air to breathe may be the key to making such a trip possible.

644: Tracking Meteoroids

If you visit a dark sky location like the Cosmic Campground International Dark Sky Sanctuary in New Mexico you are very likely to see a meteor streaking through the night sky some 70 miles or so above you. These streaks of light are caused when meteoroids made up of tiny bits of rock and dust orbiting the Sun collide with the Earth’s atmosphere at speeds of as much as 45,000 mph. Where they came from has long been a mystery.

Recently a group of Scientists led by Dr. Peter Jenniskens of the SETI Institute published an article in the Journal Icarus which shows that many of the meteoroids which become meteors or shooting stars when they enter our atmosphere come from comets which have passed near Earth as long as 4000 years ago. Their data was obtained using the NASA funded CAMS Project which features clusters of special cameras which track fireball meteors simultaneously at more than 19 locations world wide. By triangulating a fireballs trail researchers are able to calculate the precursor meteoroids orbit before it enters our atmosphere. These measurements go into a data base containing the orbits of 2.2 million tiny meteoroids.

Dr. Peter Jenniskens and his team of researchers searched this data base to find that as many as 14 comets which came to less than 4 times the Moon’s distance from us as long as 4,000 years ago are detectable as meteor showers in the present era. These results make us aware of potentially hazardous comets from the past which could come into our space again in the future. 

For Travelers in the Night this is Dr. Al Grauer.

End of podcast:

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