To Mars and Back Again: Planetfest '21 - Beyond Mars

 

"My first wish would be for Mars to blow up so we can look at the rest of the solar system."

Joseph O'Rourke
Assistant Professor ASU School of
Earth and Space Exploration

The theme of the Planetary Society's Planetfest '21 conference is the exploration of Mars, but Beyond Mars: Exploring Other Worlds, the third session on my conference calendar, provides some balance for the event's focus on Mars by looking at other opportunities for exploration and investigation in the solar system.

Dipak Srinivasan, Engineer and Civil Space External Engagements Lead at Johns Hopkins University Applied Physics Laboratory, opens the discussion with a simple statement:

"If there's water, there's life."

On that basis, the solar systems has multiple locations that offer the possibility of life. Europa, the fourth largest moon of Jupiter, is an ice world, and Titan, Saturn's largest moon, has ten times as much water as Earth. Srinivasan is currently involved in missions aimed at exploring both of these satellites: the Europa Clipper mission, and the Dragonfly mission to Titan.

Srinivasan explains that Clipper, scheduled for launch in 2024, will not be looking for life as such, but rather looking for conditions that would support life: water, the right chemical conditions, some form of energy, such as heat, and time - "life needs time to happen". He considers that the discovery of life on Europa would be "transformative".

He points out that there is a period of time when earth "had no biology, just chemistry" and suggests that Titan may be on the verge of same transition that Earth underwent billions of years in the past. Methane is to Titan as water is to Earth, with both clouds and lakes of methane, and Srinivasan sees the flying rotor-driven Dragonfly probe as the best option for exploring in Titan's combination of low gravity and dense atmosphere.

Interestingly, Maitrayee Bose, Arizona State University Assistant Professor at the School of Earth and Space Exploration, and Brett Denevi*, John Hopkins Planetary Geologist are looking for the same thing in two very different places: the history of our solar system.

Bose is studying small bodies like asteroids and comets, ranging in size from 10 meters to 500 kilometer - as she says, "The best things come in small packages." (Although I'm not convinced that a 500 kilometer piece of space rock counts as a small package.)

These small bodies tell us much about the history of our solar system, how planets form and why they look the way they do. They were the first objects that formed and then accreted to form the larger bodies that became planets.These ancient rocks retain a record of the conditions in the early solar system, and the processes and collisions that took place. 

Bose comments, "They're so diverse, and each one is telling us a story of its own, a key piece in the evolution of our solar system. They also help to answer the question of why Earth is so special, why does it have so much surface water compared to the other planets, how earth got its water, why it retained it, what different kinds of small bodies may have provided that water?"

Denevi is conducting her search for the history of the solar system on the Moon.  There are multiple lunar missions coming up in the near future, the first ones since 1972, with seven robotic landers currently planned between now and 2024, two of which will launch later this year.

These robotic probes will be investigating some of the questions that have been on hold over the last 50 years, and learning more about how the Earth and Moon were shaped by impact events early in their history.  Denevi explains that the Moon is a better candidate for this process for a very simple reason: "On Earth, we live on this beautiful geologically active world but the problem with that - at least it's a problem for weird planetary geologists like me - is that the Earth's surface is constantly being refreshed by plate tectonics and weathering, so we can't look back into its very earliest history, and on the Moon we don't have those annoying issues."

In Denevi's opinion, the Moon offers crucial information regarding what was happening in the solar system approximately 4 billion years in the past, the point at which life began to emerge on Earth.  The Moon shows evidence of massive impact events taking place, such as the one that created the Mare Imbrium crater, one of the largest impact craters in the solar system. Similar events on Earth's surface would have been catastrophic, vapourizing oceans and sterilizing the surface down to a hundred meters. Precise information from the Moon's craters will help to understand how those impacts would have affected the Earth.

Joe O'Rourke, Assistant Professor at the ASU School of Earth and Space Exploration, serves on the Steering Committee for NASA’s Venus EXploration and Analysis Group. He's both surprised and disappointed that Venus has been somewhat ignored in terms of missions - in his opinion, it's odd that Titan and Europa are receiving more attention. (He's not wrong, there have been multiple Russian landings on Venus, compared to a single multiprobe mission by NASA almost 45 years ago in 1978.) O'Rourke considers Venus to offer the same opportunities for exploration and research as Mars, including the possibility of surface water in its distant past.  

Future Venus missions under consideration are VERITAS, proposed for a 2026 launch date, that would undertake high definition global radar mapping of the Venusian surface, and DAVINCI, an atmospheric probe that would make a surface landing as well.**

The group had a full wish list for future missions: Io, Triton, Ceres, the Saturn Trojan points, the planned Viper lunar missions, and, of course, Joe O'Rourke's fervent desire that Mars would just blow up and get out of the way.

- Sid

* Denevi has an asteroid named after her, which certainly gives her an edge in terms of street cred.

 

** There are obviously two very different naming conventions in play here. VERITAS stands for Venus Emissivity, Radio Science, InSAR, Topography And Spectroscopy, and DAVINCI is Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging.  Dragonfly is apparently just a cool name for a flying planetary probe.

 

To Mars and Back Again: Planetfest '21 - Mars Mind Meld

"The rovers are our proxies - their shadows on Mars are our shadows."

Bethany Ehlmann
Planetary Society president;
Professor of Planetary Science
and Associate Director, Keck Institute
for Space Studies, Caltech

Since its inception in 1980, the Planetary Society has staged ten Planetfests to commemorate significant milestones in space exploration, starting with the Voyager 2 flyby of Saturn in 1981, and then of Neptune in 1989, where Chuck Berry performed Johnny B. Goode in recognition of the song's inclusion on the gold record album attached to both of the Voyager probes.* Subsequent Planetfests have recognized events such as the unsuccessful Mars Polar landing in 1999, the Spirit rover's safe touchdown on Mars in 2004, and Curiousity's in 2012.

The most recent Planetfest, in honour of NASA's Perseverance Mars probe, took place this last weekend via Zoom. (I was a little surprised by the timing, in that if they'd waited another week, we could have been celebrating the probe's arrival on the red planet, but the organizers may well have decided that an unsuccessful landing would have put a damper on the event.)

The two-day celebration of Martian exploration featured an eclectic array of speakers, including an impressive selection of planetary scientists, engineers and NASA representatives; well-known science fiction authors Kim Stanley Robinson and Andy Weir; and Star Trek: Voyager actor and space exploration advocate Robert Picardo in conversation with producer, director and writer Brannon Braga, best known for his work on three television series and two movies in the Star Trek franchise.

This varied group of speakers, united by their shared passion and commitment to both the present and the future of space exploration, covered a wide range of fascinating, informative and insightful topics over the two days of the event.

After an introduction by Planetary Society CEO Bill Nye, Planetary Society president Bethany Ehlmann delivers the keynote speech for the weekend - Mars Mind Meld: Everything You Ever Wanted to Know About Mars. Her presentation provides a broad overview of Martian exploration, and looks at the questions that probes such as Perseverance will help to answer.

For Ehlmann, the most important question is: what happened to Mars that eliminated water and possibly life? Although there are only a few weeks of the Martian year when the environment allows liquid water to exist, Mars is covered with evidence of water - as Ehlmann points out, "the plumbing of Mars is exposed" - there is visible erosion of the surface by water, clay substrates, formations like those found around geothermal springs on Earth, and so on, all pointing to a time in the past when Mars may well have been more habitable than it is now. 

Provided all goes well on the 18th, Perseverance's extended mission on the surface of Mars will take it up the Midway delta that feeds into the Jezero Crater landing site**, allowing it to explore successive layers of Martian history as it proceeds up out of crater and moves a billion years further back in time.

In addition, the probe is not only an explorer, but a cacher, with the ability to store drilled samples from the various exposed strata for eventual return to Earth. It's hoped that these samples, each about the size of a piece of chalk, will allow scientists on Earth to answer questions about Martian climate, Martian change, and Martian life.  They're playing the long game on the process:  the current strategy for sample return involves a three year wait.

The eventual exploration of Mars by humans will immeasurably accelerate the process of scientific investigation, but until then, the robotic rovers act as proxies in our place - as Ehlmann eloquently puts it, "their shadows are our shadows".

- Sid

* It also included a needle, cartridge, and symbolic instructions on how to play the record - which, at this point in time, a lot of people on Earth would also need.

** I was charmed to see that she had a Post-It™ tab on the Martian globe in her office to indicate the Perseverance landing site.

 

Virtual Dreams III: Thanks anyway.

The Oculus Quest 2 operating system allows users to select from several virtual environments that acts as a backdrop for the headset's operating system and menu screens - not surprisingly, I've chosen the space station setting.

To my amusement, I recently learned that it’s possible to walk around in this virtual environment and explore the different rooms - provided that you do it in the middle of an empty football field or something similar, there doesn't seem to be any way to teleport from place to place.  My congratulations to Oculus on creating an explorable virtual environment that virtually no one can explore. 

- Sid