NASA’s OSIRIS-REx: NASA

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OSIRIS-REx spacecraft starts its two-year-long journey back to Earth.

About OSIRIS-REx

It is the first U.S. mission to collect a sample from a near-Earth asteroid, called Bennu (formerly 1999 RQ36) and return it to Earth for study.
- Scientists will use the asteroid samples to study the formation of the solar system and of habitable planets such as Earth.
- Analyzing the sample will help scientists understand the early solar system, as well as the hazards and resources of near-Earth space.
It was built by Lockheed Martin and launched in 2016.
The spacecraft contains five instruments meant to explore Bennu including cameras, a spectrometer and a laser altimeter.

Objectives

The OSIRIS-REx name is an acronym of the mission objectives, which are:

Origins: Return and analyze a pristine carbon-rich asteroid sample.
Spectral Interpretation: Provide ground truth or direct observations for telescopic data of the entire asteroid population.
Resource Identification: Map the chemistry and mineralogy of a primitive carbon-rich asteroid.
Security: Measure the effect of sunlight on the orbit of a small asteroid, known as the “Yarkovsky effect” – the slight push created when the asteroid absorbs sunlight and re-emits that energy as heat.
Regolith Explorer: Document the regolith (layer of loose, outer material) at the sampling site at scales down to the sub-centimetre.

Sample Collection and Return

Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – an articulated robotic arm with a sampler head to collect a sample of Bennu’s surface.
OSIRIS-REx Sample Return Capsule (SRC) – a capsule with a heat shield and parachutes through which the spacecraft will return the asteroid sample to Earth.

Image Courtesy: CSA

Achievements

The spacecraft found traces of hydrogen and oxygen molecules – part of the recipe for water and thus the potential for life – embedded in the asteroid’s rocky surface.
In October 2020, the spacecraft briefly touched asteroid Bennu, from where it collected samples of dust and pebbles.
A sample of primordial rock is now on its way to Earth, where scientists will analyze it to learn about the origins of our solar system and life on Earth.
When the spacecraft finally returns in September 2023, it will bring back the largest sample collected by a NASA mission since the Apollo astronauts collected samples of Moonrock.

Asteroids

Asteroids, sometimes called minor planets, are rocky, airless remnants left over from the early formation of our solar system about 4.6 billion years ago.
The current known asteroid count is: 1,080,514.
Most of this ancient space rubble can be found orbiting the Sun between Mars and Jupiter within the main asteroid belt.
Asteroids range in size from Vesta – the largest at about 329 miles (530 kilometers) in diameter – to bodies that are less than 33 feet (10 meters) across.
The total mass of all the asteroids combined is less than that of Earth’s Moon.
Those like Bennu contain natural resources such as water, organics and metals.
Future space exploration and economic development may rely on asteroids for these materials.

Image Courtesy: Socratic

Asteroid Bennu

It is a skyscraper-sized asteroid some 320 million km from Earth.
It is named after an Egyptian deity.
The asteroid was discovered by a team from the NASA-funded Lincoln Near-Earth Asteroid Research team in 1999.
It likely broke off from a much larger carbon-rich asteroid about 700 million to 2 billion years ago.
Because its materials are so old, Bennu may contain organic molecules similar to those that could have been involved with the start of life on Earth.
It likely formed in the Main Asteroid Belt between Mars and Jupiter, and has drifted much closer to Earth since then.
There is a slight possibility that Bennu, which is classified as a Near Earth Object (NEO), might strike the Earth in the next century, between the years 2175 and 2199.

Near Earth Object (NEO)

NEOs are comets and asteroids nudged by the gravitational attraction of nearby planets into orbits which allow them to enter the Earth’s neighbourhood.

Comets

Comets are frozen leftovers from the formation of the solar system composed of dust, rock and ices.
They range from a few miles to tens of miles wide, but as they orbit closer to the sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet.
This material forms a tail that stretches millions of miles.

Sources: IE

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