. . .
Stink peered up at the sky with his asteroid-proof X-ray vision goggles.
from Stink Moody in Master of Disaster
written by Megan McDonald
illustrated by Erwin Madrid
Candlewick Press, 2015
As I discovered when I wrote about the Perseid shower on August 15, 2023, most asteroids are chunks of rock that orbit the sun in the Asteroid Belt between Mars and Jupiter. Occasionally one of these chunks is thrown out of its orbit and heads toward Earth, but most burn up as they reach our atmosphere.
In 1999, scientists used electro-optical telescopes operated by the Massachusetts Institute of Technology Lincoln Near-Earth Asteroid Research (LINEAR) program to discover the asteroid originally known as 1999 RQ36.
Staff scientists at MIT sorted through photos. They wanted to explore an asteroid not too close, not too far away, with a slow enough rotation, and carbonaceous. They deduced 1999 RQ36 was made of carbon and probably water. Just what they were looking for!
By 2013, the OSIRIS-REx, (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) team deemed the little, rocky chunk worthy of owning its own name. Michael Puzio, a 3rd grader from North Carolina won their naming contest. Bennu is the name of an Egyptian god associated with Osiris, the Egyptian god of immortality.
Aimed toward Bennu, NASA launched OSIRIS-REx on September 8, 2016, for its 200-million mile journey. It is the first U.S. mission to collect a sample from an asteroid. Besides the qualities the MIT team was looking for, NASA chose Bennu for several reasons.
Its rocks offer insight into our own history during the time when Earth was forming, about 4.5 billion years ago.
There is evidence that asteroids like Bennu delivered their rich, organic compounds (that make up all known life) to Earth when they smashed into our planet billions of years ago, just as the conditions for life were starting to emerge.
Using the material from Bennu, scientists can study how planets formed and how life began.
Bennu’s material can help scientists understand the consequences of asteroids that impact Earth.
Unlike most asteroids found in the asteroid belt, Bennu crosses Earth’s orbit, about every six years, making a spacecraft’s round trip from Earth easier and quicker, if you’re a NASA scientist.
When OSIRIS-REx arrived and lightly touched Bennu to collect its material, scientists discovered that the surface was held together not by cohesion, but by micro-gravity. If the thrusters were not on, the craft would have sunk into the surface of dust, pebbles, rocks and boulders. The NASA team wonders what other surprises Bennu will reveal.
On Sept. 24, 2023, OSIRIS-REx's round-trip to Bennu was complete, seven years after its launch. It traveled back to Earth at 27,650 mph and, with the aid of two parachutes, made a soft landing at the Department of Defense’s Utah Test and Training Range near Salt Lake City.
Because scientists will look for organic material, every care had to be taken to protect the sample from possible earthly contaminates like water vapor, microscopic organic particles, and dust. The sample from Bennu cannot contaminate Earth with living organisms. The harsh radiation environment in space took care of that.
OSIRIS-REx’s ground team was dispatched quickly, and in just outside of an hour the module was transported to a clean room where it was wrapped up for safe transport, still unopened, to NASA’s Johnson Space Center in Houston.
When the module is opened, OSIRIS-REx is expected to have delivered about 1/2 a pound of material. It will fit into a 1-cup measure. One fourth of Bennu’s material will be studied by 233 scientists from 38 global institutions who make up the OSIRIS-REx team. About 70% of the material will be preserved at the Johnson Space Center for study by scientists not affiliated with NASA and for educational displays for the public. The little bit that’s left will be given to scientists in Canada and Japan for their own studies.
About 20 minutes after the module was unloaded, the spacecraft was renamed OSIRIS-APEX, (OSIRIS-Apophis Explorer). Its engines were fired up, and it left Earth for its new destination, asteroid Apophis. It will begin exploring this new asteroid when it arrives in 2029.
Bennu is small, only about 1/3 of a mile (500 meters) wide through its equator. If Bennu struck Earth, it could do some damage, but the asteroid that killed the dinosaurs 66 million years ago was 6 miles in diameter.
Bennu is old, four and a half billion years old. When its tiny gifts of dust, pebbles, rocks, and boulders are uncovered, it may be able to tell scientists how the solar system formed. It might give some evidence of the origin of life.
It might even be able to show us how the planets learned to dance around the sun.
I finished reading The Midnight Library by Matt Haig (Viking, 2020). The author explores what could happen if we are allowed to erase our regrets, one at a time, and see what each life would look like if we made different choices. SPOILER: The ending reminded me of The Wizard of Oz without Dorothy needing to click her ruby slippers.
-—Be curious! (and keep looking up)