OSIRIS-Rex: Dinosaur or science mission?

On September 8th, 2016, NASA used an Atlas V (411) ¹ to launch the OSIRIS-REx ² asteroid sample return mission ³ to asteroid Bennu⁴.

So let's review what that means:

1) The Atlas V (411) is a two-staged rocket built and operated by United Launch Alliance that has been in service since 2002, primarily used for launching military satellites and often sending robotic probes to far-off solar system destinations. As launchers go the Atlas V has an incredible reliability record with 65 straight successful launches. There have been a few minor in-flight issues here and there but the "Mighty Atlas" (as ULA's CEO is fond of calling it) always gets the job done. As successful a rocket as it may be, it's not been without controversy. In fact, in the wake of Russia's incursion into Crimea the US government temporarily banned the import of Atlas V's first stage engine because it is built in Russia.

     Atlas V comes in several variants, which is the reason for the "411" code in this instance. That means that it has:

• A 4-meter diameter (13.1 ft) payload fairing that protects the payload during flight through the atmosphere. A 5-meter (16.4 ft) fairing is also available for larger satellites.
• 1 side-mounted Solid Rocket Booster, built by Aerojet Rocketdyne, to provide additional thrust early in the flight. Atlas V can use up to five SRBs.
• 1 Centaur upper-stage engine to take the payload from the upper atmosphere to its final orbit. This upper-stage can have one or two engines.

 Below you can watch the launch of an Atlas V 551, one of the most powerful variants.

For more information, check out ULA's website.

2) OSIRIS-REx is unfortunately NOT a dinosaur but a NASA mission with perhaps the most cumbersome acronym of all time. Its full name is the Origins Spectral Interpretation Resource Identification Security - Regolith Explorer. The mission is designed to visit an asteroid (Bennu) that occasionally passes close to the Earth, to study and characterize it. OSIRIS-REx will

• Measure how sunlight absorbed then re-radiated by the asteroid's surface causes it to rotate and change its orbit around the sun over time--called the Yarkovsky Effect. This could affect how close Bennu comes to Earth--possibly close enough to impact our planet in the future.
• Map the distribution and chemistry of Bennu's surface.
• Return a sample of the asteroids loose rocky, dusty surface material called "regolith." More about this in the section below.

 

3) Asteroid sample return is OSIRIS-REx's primary mission. After orbiting Bennu for an extended time to understand its gravity and rotation, an arm will extend to the surface and release a burst of gas to push surface material into a surrounding screen where 2 to 70 ounces (60 to 2000g) of the material will be captured. That capture device (called TAGSAM) will then be encased in a heat shield and make a fiery return to Earth's surface. This will allow the samples to be handled and analyzed by scientists with a wider range of observational and testing equipment than if mission planners sent a select few instruments into space. It will also allow scientists to save samples for future generations to study with currently-unknown testing processes that may be developed in the decades to come.

4) Asteroid Bennu is a 1,600 ft (500m) wide asteroid and, like all asteroids, is a remnant of the formation of our early solar system. After gravity had gathered most of the material into planets and moons what was left over became the asteroid belt. Radar and visual observations lead scientists to believe that Bennu is extremely high in carbon which also gives it a remarkably low level of reflectivity. This has made observations difficult but OSIRIS-REx's visit will provide first-ever close up imagery and radar data on this asteroid. That data will be compared with Earth-based observation that may reveal better observation methods for the future that could come in handy nearing the years 2175 to 2196 when Bennu stands a 1-in-2700 chance of impacting the Earth. Looks like humans of the future could either use good luck OR good science.


Have you somehow reached the end of this and have a desire to read MORE detailed information about the OSIRIS-REx mission? Well you can click this link for the official mission factsheet.