by S. Prasad Ganti

The spacecraft OSIRIS-REx passed close to the Earth to paradrop off a sample of material it scooped from the asteroid Bennu about three years back. The sample has landed safely in the deserts of Utah, while the spacecraft is on its way to another asteroid Apophis. The sample will be taken to John Space Center where it will be meticulously studied for months and years. 

It is not the first time we got samples from outer space beyond the moon. The Genesis spacecraft which collected solar wind particles dropped a sample in 2004, but due to some miscalculation in the design of the landing system, the sample crashed to the Earth. But some of the solar wind particles were recovered and studied. One of the conclusions of the study is that Earth lost some of its atmosphere early in its history.

Next, the Stardust spacecraft picked up samples from a comet called Wild-2. The samples landed safely in the deserts of Utah in 2006. The comet is considered a fresh comet since it made very few orbits around the Sun. It lost very few of its original particles of gas and dust. 

Similarly the Japanese spacecraft Hayabusa 2 visited the asteroid Ryugu and dropped off samples in 2020. Earlier, the lunar samples have been returned by the Chinese, Russians and NASA. In addition to the Apollo astronauts bringing back some of the samples with them. 

Launched in 2016, OSIRIS-REx (having a fancy acronym – Origins, Spectral Interpretation, Resource Identification, Apophis Explorer, Regolith Explorer). In 2020, it did a touch and go scooping of the sample by hovering over the surface of Bennu and kicked up the regolith using its nitrogen thrusters. 

Asteroids are found in large numbers in the Asteroid belt, between the orbits of Mars and Jupiter around the sun. These are the remnants from the formation of our solar system. Something like the garbage dump where excess construction material are thrown away. Fortunately, such construction garbage dumps provide information on the material that went into the construction of the building. 

These efforts to collect samples are involved with expensive space missions. Besides these, there are free samples which come to the Earth all the time. The book “Impact” by Greg Brennecaka covers the phenomena of hundred tons of meteoritic material which falls to the Earth from space each day. Most of them are in the form of dusty meteorites. Some are rocks and bigger objects which burn off most of the time through the perilous journey through the Earth’s atmosphere. This tells us the importance and the challenges of safely guiding the returned samples to the surface of the Earth. 

Meteorites are postulated to have brought the  metals found in the Earth’s crust, organic material, and water. The original metals from the formation of Earth sank to the molten core long ago. What is being mined today are courtesy the carriers from outer space.

Some of the meteorites called carbonaceous chondrites have a matrix-like structure which holds water and organic molecules. Some of the organic molecules are  the L (left) type amino acids which are the basis of higher forms of life like us. Meteorites also contain phosphorus, a critical component for life, but not found in reduced form on earth. We might owe our existence to these gifts from outer space. And we crave to study them and bring more of them by sending return missions into outer space. 

The human quest to understand our origins and possibly the originator are centuries old. Although the spiritual and scientific methods differ, the common quest still remains the same.