ESPAÇO
Missão OSIRIS-REx ao asteróide Bennu
January 24, 2019 -
A nave OSIRIS-REx vai aterrar em 2020 para recolher uma amostra da
superfície de Bennu – um asteróide rico em carbono que pode conter
os precursores moleculares para a origem da vida na Terra.
Of more than 500,000 asteroids in the solar system, Bennu is one of only five with the right orbits, sizes and carbonaceous compositions for a sample-return mission. The 510-metre wide asteroid is probably part of a much more massive asteroid -- remaining debris from the formation of the solar system some 4.6 billion years ago.
Launched in September 2016, OSIRIS-REx arrived at Bennu, 110 million kilometres from Earth, in December 2018. On New Year’s Eve, the spacecraft went into orbit around Bennu.
Starting in February, the OSIRIS-REx team will perform a series of close flybys of Bennu, taking high-resolution images of the asteroid to select a sampling site.
During the summer of 2020, the spacecraft will briefly touch the surface of Bennu using a two-metre-long robotic arm, its Touch-and-Go Sample Arm Mechanism (TAGSAM) to retrieve a sample.
The sample head will use high-pressure nitrogen to kick up regolith -- dust and rock particles from millions of years of meteoroid impacts -- during a five-second contact. The TAGSAM can capture particles up to two centimetres in diameter while contact pads can pick up fine dust particles up to one millimetre in diameter.
The OSIRIS-REx team hope to collect up to two kilograms of regolith. The sample will be sealed in a return capsule for the cruise back to Earth, arriving in September 2023.