This Week in Space 177: Life on Mars?

Date: September 12, 2025
Host(s): Rod Pyle, Tarek Malik
Guest: Dr. Michael Tice, Texas A&M planetary geologist and co-author of the recent Mars biosignature paper

Overview

This episode of "This Week in Space" zeroes in on intriguing new findings from NASA’s Perseverance rover that may represent the best evidence for ancient life on Mars yet. Rod Pyle and returning co-host Tarek Malik are joined by Dr. Michael Tice, co-author of the recently published paper: "Redox Driven Mineral and Organic Associations in Jezero Crater, Mars." The conversation covers the context, science, methodology, implications, and ongoing debate about whether Perseverance has found true Martian biosignatures.

Main Discussion Points & Insights

1. NASA, China, and the Moon Race (03:54 - 07:41)

• Interim NASA administrator Sean Duffy has stated beating China back to the Moon is the agency's top goal, calling it the “second space race.”
• Duffy emphasized a balanced approach, not sacrificing safety for expediency:

  “We are going to beat China to the moon... We are going to do it safely, we're going to do it fast, and we're going to do it right.” (06:12 – Tarek Malik)

• Recent Senate hearings highlighted the concern that, if current trends continue, China's lunar program could surpass NASA’s.

2. Satellite Revelations and Space Policy (10:07 - 12:49)

• Maxar Technologies’ satellites captured a Starlink satellite photobombing an image of a secret Chinese airbase, showcasing the ever-evolving capabilities (and security risks) of Earth observation.
• Tarek draws parallels to the transparency/implications of sharing high-res satellite imagery:

  “It’s a nice public reminder that satellites in space can see everything.” (11:18 – Tarek Malik)

3. Headline Amusements: James Webb Spots Stellar Jets (12:49 - 14:13)

• A lighthearted moment: James Webb Space Telescope imaged nebula SH2 284, highlighting immense stellar jets and offering “perspective on stress”—even stars “let off steam” in cosmic fashion.

4. Audience Questions & UFO Lingo (15:13 - 16:25)

• Brief, humorous tangent on alien conspiracies, invoking “aliens in Congress” and Senate UFO hearings.

Spotlight: Life on Mars - Perseverance’s Big Find

(19:06 – 71:48)

Introduction to Dr. Michael Tice

• Dr. Tice’s background: environmental engineering, sedimentary geology, a circuitous route to Mars research:

  “I wound up taking my first geology course my junior year and thought, no, wait, this is the thing to do… at that point, most of the research was being funded by NASA because they were interested in essentially doing the same thing on other planets.” (21:42 – Dr. Michael Tice)

The Discovery in Jezero Crater

What was found?

• The team found “leopard spots”—distinct mineral patches with unusual redox gradients and organics in Martian rocks.
• These features represent a possible biosignature:

  “There was what we’ll call a redox gradient… That’s the kind of thing that life really likes. Organisms take advantage of redox gradients like that in order to make their living.” (33:44 – Dr. Tice)

• Dr. Tice details the careful, skeptical scientific process:

  “We can think of any number of things that would do that… [But] we just couldn’t come up with anything that did as good a job explaining these things as potentially life.” (28:24 – Dr. Tice)

Technology and Methods

• PIXL (Planetary Instrument for X-ray Lithochemistry) and SHERLOC were the crucial instruments:

  “PIXL fires a small X-ray beam at the rock… and by counting the X-rays… we’re able to tell not only what [elements], but also how abundant they are.” (36:19 – Dr. Tice)

• Perseverance’s capabilities are at the "bleeding edge," with post-landing software improvisation amplifying science return:

  “It’s an amazing combination of science and engineering on the fly that I feel like it’s been a real privilege to get to participate in.” (41:28 – Dr. Tice)

Biosignature or Geochemistry? Potential Non-Life Explanations

• The main alternative: high-temperature geochemical processes could mimic biological sulfate reduction.
• Dr. Tice explains:

  “You can do this abiotically by heating your system up to around 120°C and doing that over hundreds of thousands to millions of years... we don’t think that happened [here].” (44:56 – Dr. Tice)

• Still, further laboratory work is needed to fully rule out non-biological origins.

Why Sample Return Matters

• Earth laboratories could run isotopic, molecular, and microscopic tests that rover-based instruments cannot:

  “We need to know a lot more about what those organics are and where they came from. There’s a lot of isotopic work that could be done... looking for the isotopic signatures of biological processes...” (56:53 – Dr. Tice)

• The potential to discover actual microfossils is small but significant.

The Evolution of the Search for Martian Life

• From "canals" and lush Martian jungles to nuanced chemical and isotopic biosignatures – science keeps refining what (and how) we search:

  “The best kind of hypotheses are the ones where you find out you were wrong about something in interesting ways, and then you go off and do the more interesting thing.” (63:13 – Dr. Tice)

• Iterative, sometimes frustrating, but always narrowing in on the truth.

Human vs. Robotic Exploration

• Ideal strategy: combine robotic sample collection over wide areas with targeted human investigation:

  “I think a combination of sample return and boots on the ground actually is the way to do things… You can’t possibly substitute one for the other. They really ought to be working in tandem.” (68:05, 68:43 – Dr. Tice)

Notable Quotes & Memorable Moments

• On the importance of measured science:

  “This is how good science with a capital S is done.” (29:43 – Rod Pyle)

• On the possibility of Martian fossils:

  “We’re all waiting for that dinosaur femur moment up there…” (58:27 – Rod Pyle)

• On the “leopard spots” and their chemistry:

  "It's actually pretty easy to [make these minerals] with the iron, but with the sulfur, making the sulfide in the center, it's not so easy [without life]." (35:34 – Dr. Tice)

• On the frustration of remote geology:

  “Man, what I wouldn't give for the ability to just walk up to a rock, and then move slightly off to an angle and see it from in with light hitting it a different way…” (52:22 – Dr. Tice)

Key Timestamps

• NASA vs China space race discussion: 03:54 – 07:41
• Starlink satellite, Chinese air base, Maxar imagery: 10:07 – 12:49
• James Webb “stellar jets” story: 12:49 – 14:13
• Interview with Dr. Michael Tice starts: 19:06
• Explanation of Perseverance’s leopard spot find: 25:47 – 35:34
• How PIXL (instrument) works: 36:19
• Why sample return is vital: 56:53 – 59:56
• Evolution of the search for life on Mars: 61:54 – 65:32
• Human versus robotic exploration: 67:08 – 68:43
• Wrap up and guest plugs: 69:03 – end

Conclusion

"Life on Mars?" highlights both the promise and challenge of searching for life beyond Earth. Dr. Tice and the Perseverance team’s findings invite cautious excitement: the best candidate for Martian biosignatures to date—strange redox mineral spots, found and analyzed with the latest rover tech. But the story is unfinished; only with future sample returns and continued nuanced science will we know if these are the fingerprints of life, strange Martian chemistry, or something in between. The journey from longing for clear answers to celebrating careful, incremental discovery is what drives the continuing saga of Mars exploration.

To keep tabs on Dr. Tice’s work, check Texas A&M’s geology department and Perseverance’s latest updates.
For more space news, follow Tarek at space.com and Rod at pilebooks.com.

Science thrives on questions; Mars just made us ask the most exciting one yet – and now, we wait for the answer.