Astronomy Astrophiz Podcast · Brendan O'Brien: Astronomers, Astrophysicists & Space Scientists

Astronomy Astrophiz 210: ProfElizabethTasker

·54 min·5 clips

Hayabusa 2 engineers debated risking the entire mission to collect a subsurface sample from a dangerous asteroid.

This episode features host Brendan O'Brien interviewing astrophysicist and science communicator Associate Professor Elizabeth Tasker from JAXA's Institute of Space and Astronautical Science. They focus on Japan's complex robotic sample-return missions to asteroids. Tasker is involved in outreach for the Hayabusa2 and MMX missions. The discussion details the original Hayabusa mission, launched in 2003 to the peanut-shaped asteroid Itokawa roughly 300 million kilometers away. That spacecraft was severely damaged by a solar flare and reaction wheel failures, forcing a delayed return where the main craft disintegrated in Earth's atmosphere in 2010. Scientists found only microscopic grains inside the recovered sample capsule. Hayabusa2 launched in 2014 to the carbonaceous, spinning-top-shaped asteroid Ryugu, selected for its scientific potential as a primitive solar system time capsule. The mission faced major challenges because Ryugu's surface was covered in boulders, with the safest landing zone measuring only six meters across. The team performed practice descents and deployed small rovers and a lander named MASCOT to gather more data. For sampling, the spacecraft used a horn to touch the surface and fire a tantalum projectile to stir material into a collection capsule. A critical debate occurred after the first successful sample collection in February 2019 over whether to risk a second attempt for subsurface material. The team proceeded by deploying the Small Carry-on Impactor, a copper plate shot into the asteroid to create a crater and expose fresh material. Hayabusa2 collected a second sample from the ejecta around this crater in July 2019. The sample capsule landed in Australia's Wimmera Desert in December 2020, while the healthy spacecraft embarked on an extended mission. JAXA implemented extreme anti-contamination protocols, including constructing the spacecraft in monitored cleanrooms and purging the sample horn with nitrogen. The team had an estimated 100-hour window after Earth landing to retrieve the capsule and place it under vacuum, a process completed in 57 hours. Analysis of the Ryugu samples shows a composition very similar to the Sun, confirming its primitive nature from 4.5 billion years ago. Researchers discovered micro-inclusions of liquid water and carbon dioxide, indicating Ryugu formed in the outer solar system where CO2 could freeze. This supports theories that Earth's water was delivered later by such asteroids. The tone is conversational, educational, and filled with narrative storytelling about space exploration challenges. Listeners interested in space mission engineering, planetary science, and behind-the-scenes stories of problem-solving will find this episode captivating. Those seeking highly technical astrophysics theory or a debate-style format might prefer other content.

As heard by us

A clear, patient look at how Hayabusa 2 sampled Ryugu.

Astrophys keeps the focus where it belongs: on the careful, fiddly work behind Hayabusa 2's Ryugu sample return. It walks through the SCI drop on April 5th in 2019, the DCAM deployment that watched the impact, and the later second touchdown that gathered material from the area…

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