NASA Spacecraft Embarks on 7-Year Mission in Search of Protein Building Blocks on Ancient Asteroid

Source: Solar System Exploration Research Virtual Institute
Story Highlights
  • A NASA spacecraft will collect a sample from an asteroid for analysis of amino acids.
  • Extraterrestrial amino acids in the sample may indicate when life was first possible on Earth.
  • The asteroid sample will be acquired by the spacecraft's state-of-the-art robotic arm.

On September 8, 2016, the OSIRIS-REx spacecraft was launched from Cape Canaveral, FL, thus beginning its seven-year journey to reach a 4.5-billion-year-old asteroid, collect a sample, and deliver it to NASA.

It has been hoped that if OSIRIS-REx can obtain a large enough sample from the asteroid, designated as Bennu, then a thorough analysis may reveal traces of protein building blocks. These building blocks, also known as amino acids, could potentially provide answers to some questions about the genesis of organic life on Earth.

Deputy principal investigator for the OSIRIS-REx mission, Ed Beshore, has explained that, given Bennu's unchanged chemical composition since the formation of the solar system, the sample will act as a time capsule.

For example, the presence of amino acids in the sample would indicate that the chemical ingredients for life were available in the solar system during the Earth's formation. However, the absence of amino acids from the sample would suggest that organic ingredients were brought to the solar system after the Earth's formation.

In other words, the results of this pioneering expedition will shed some light on the timeframe in which life was first established on Earth.

The process by which OSIRIS-REx will gather the sample is both intricate and simplistic. After maneuvering around Bennu's sporadic orbit and rotation for two years, OSIRIS-REx will use its 10-foot robotic arm, also known as the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), to shoot a puff of nitrogen gas onto the surface of Bennu and create a cloud of debris that it will then vacuum into its system.

Upon concentrating the debris into a 60-200 gram sample that is suitable for analysis, OSIRIS-REx will store it in the Sample Return Capsule, which will later function as a protective vessel when returning the sample to Earth.

Source: The American Astronautical Society
The American Astronautical Society (AAS) has gathered a large amount of data on the trajectory and accuracy of TAGSAM by utilizing the Monte Carlo method of analysis. The Monte Carlo method is often used to determine the risk and uncertainty of a project, such as sample acquisition by TAGSAM.

The maneuvering error of TAGSAM is close to 0.3 mm/s and the velocity error is less than 2 cm/s. The AAS considers these values to be acceptable, but also discovered that the altitude of the robotic arm is problematic, seeing as it exceeds the 4 degree error that is permissible for the mission. In order to alleviate this issue, an on-board guidance system was recommended and subsequent experimentation has proven that it would increase both precision and accuracy of the sampling sequence.

The data is enough to conclude that TAGSAM has a minimal amount of error, meaning that the mission is likely to be a success, especially considering the fact that an on-board guidance system for TAGSAM was implemented prior to the launch of OSIRIS-REx.

The highly anticipated asteroid sample will be dropped from OSIRIS-REx and delivered to Earth on September 24, 2023.

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