July 18, 2025

This Week in Space 169: The Day Mars Died

1 hour 18 minutes

Sixty years ago this week, the Mariner 4 probe sped past Mars, the first to succeed in this then-brash undertaking. The technology was unbelievably primitive, yet effective, sending back 22 low-resolution video frames of the Red Planet. On that day, the wee hours of July 15 at JPL in Pasadena, the Mars of the romantics died. What had long been viewed as a slightly colder, somewhat drier, near-twin of Earth ended up having just a trace of an atmosphere and looked more like the moon--bone dry and pummelled by craters. Rob Manning, JPL's Chief Engineer Emeritus, joins us for this look back at that mission and the first images returned of another planet from space.

Headlines

Apollo-Soyuz 50th Anniversary: Rod and Tariq marked 50 years since the historic Apollo-Soyuz docking, a significant event for international cooperation in space.

Starliner: Boeing's Starliner won't fly again until early 2026, with good odds that it will be an uncrewed flight.

Mars Meteorite on Earth: Tariq shared his awe-inspiring experience viewing the largest piece of Mars on Earth, a 54-pound meteorite discovered in 2023 that recently sold for $5.3 million.

Main Topic - The 60th Anniversary of Mariner 4

Rob Manning, JPL Chief Engineer Emeritus: Rob Manning joins the host to discuss his extensive career working on most of NASA's Mars missions.

Mariner 4's 60th Anniversary: The show's discussion highlighted the 60th anniversary of Mariner 4, which was America's first successful spacecraft to Mars.

The "Death" of Mars: Mariner 4's images shattered romantic notions of Mars, revealing a cratered, arid planet with a thin atmosphere.

Mariner 4's Camera Technology: Rob Manning detailed the technical challenges involved in adding a Vidicon tube TV camera to Mariner 4, emphasizing the difficulties in managing data size and ensuring functionality in space.

Hand-Colored Mars Image: Scientists famously hand-colored Mariner 4's first black and white digital image.

Mariner 4 Scientific Discoveries: Key scientific findings from Mariner 4 included the discovery of Mars' extremely thin atmosphere, roughly 1% the density of Earth's, and the absence of a strong global magnetic field.

Challenges of Martian Landings: Rob underscores the extreme difficulty of landing on Mars due to its thin atmosphere, which rendered early concepts like glider landings impractical and dangerous.

Legacy of John Casani: Rob praises the recently passed John Casani, Mariner 4's manager, for his pivotal role in advocating for the camera's inclusion and inspiring innovation at JPL.

"Properly Paranoid" Approach: Rob discussed the concept of being "properly paranoid" in space engineering, stressing the importance of meticulous testing and proactive risk mitigation for high-stakes missions.

Hosts: Rod Pyle and Tariq Malik

Guest: Rob Manning

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