OSIRIS-REx spacecraft starts a seven-year mission to snag samples from a nearby asteroid
Humans have sent many robots out to explore our solar system, but almost always with one-way tickets. Between the variety of observations and measurements that can be done remotely, plus the difficulty of deploying any device into space that plotting a return course isn’t worth the trouble. However, sometimes monitoring the various wavelengths of energy reflected of a distant object isn’t enough, and contact must be made. On Mars, this is one reason the Curiosity rover is equipped with instruments like the SAM, or Sample Analysis at Mars, which makes use of physical analysis of Martian soil. The OSIRIS-REx mission launched today will take things a step further, flying out to an asteroid in order to retrieve a sample for analysis back on Earth. This time, a piece of our space robot gets to come home.
Arriving soonish at an asteroid near you
After blasting off today, The OSIRIS-REx spacecraft will start the four-year process of syncing up with an asteroid known as 101955 Bennu. The asteroid is considered a fairly close neighbor to Earth, and even has a minuscule chance of one day colliding with our planet, but for the delicate maneuvers required later in the mission, the spacecraft needs time to put itself in the right place at the right speed. During that four-year approach period, it will even use a closer flyby of Earth to get a slingshot effect from our planet’s gravitational pull, a maneuver also used by various other missions, including the Rosetta spacecraft on its ten-year journey to Comet 67P.
Once in position alongside the Bennu asteroid, OSIRIS-REx will first carefully map the asteroid to help find the perfect approach location. Bennu has already been observed closely with visible and infrared telescopes, so it’s expected to be a suitable target for this mission. We know it’s around 1,614 feet in diameter, and rotates once every 4.3 hours, but the scans made up close and personal should help determine an optimal point of interaction. Once selected, the spacecraft will slowly approach the surface of the asteroid but not actually land. Moving slower than a mosquito through the air, the craft is instead there to jet a blast of nitrogen gas at the asteroid, kicking up rock and dust that it can then collect to take home. The first puff doesn’t have to be perfect, but by the third try scientists hope to have collected between 60 grams to two kilograms of material as a fairly amazing souvenir.
Discovery from the dust
There’s more to the dust than the bragging rights of pulling off such a maneuver, of course. After three more years of travel, the OSIRIS-REx spacecraft should be back near Earth, at which point it will launch its dusty payload in a capsule that will parachute into the Utah desert. The spacecraft will continue onward in an orbit around the Sun, but the debris recovered from Bennu should then help us answer a lot of questions about our past and maybe our future. On one hand, we expect to find some organic compounds mixed in from the carbon-rich asteroid, which may help us better understand the origins of our solar system and maybe life on Earth. Looking forward, this mission will also help confirm the odds of Bennu one day impacting Earth, and knowing its composition and structure will greatly help us plan for such a scenario. It won’t be the first piece of asteroid we’ve had delivered back to Earth (that was done by the Hayabusa spacecraft in 2010) but there are plenty more questions that will be best answered by getting our hands dirty.
Source: Thursday Night, NASA Launches a Mission to Sample an Asteroid ... and Bring a Piece of It Back to Earth by Phil Plait, Bad Astronomy