Is a 'Quest for Life Elsewhere' a solid rationale for Space?

Robotic missions to Mars, thus far. To this list we can now add the successful launch, November 5, of India's Mars Orbiter Mission (MOM).

Paul D. Spudis

The Once and Future Moon
Smithsonian Air & Space

An interesting report in the Washington Post relates that the current Mars rover Curiosity (MSL) has found no evidence for methane on that planet, a finding that contradicts some earlier reports of the presence of that gas in the martian atmosphere.  The report goes on to say that this finding “disappointed” some members of the Curiosity science team.  Supposedly after earlier studies detected methane in telescopic spectra, they had “high hopes” for a positive result from the Curiosity rover.

Various reactions to this revelation are interesting, as they suggest something about the current mania for the search for extraterrestrial life, as well as something about the ultimate rationale for our national space program.

Mars Orbiter Mission (MOM), subsequently launched successfully November 5, under preparation for a prelaunch test at the ISRO Satish Dhawan Space Centre, SHAR, at Srihairkota [ISRO].

Whence comes this obsession and why does it drive our space efforts and dominate space news coverage?  Science fiction dreams have long been a part of the space effort, with many working in the field receiving their first exposure to space topics via that medium played out in print, film and video.  From bug-eyed Martians invading the Earth to slimy, acid-dripping killers stowed away aboard spacecraft, the obsession with extraterrestrial life took firm hold of the human imagination.

This sense of fascination is so strong that space advocates have tried to harness it as a way to justify (if not coerce) increased amounts of spending on the civil space program.  After the end of the Apollo program, with its clearly geopolitical goals accomplished, the space program needed a new long-term rationale, one that would ensure its continuation over many years.  Carl Sagan, an astronomer fascinated by the possibility of life on other worlds, emerged as the principal spokesman for the idea that searching for ET was the “true and good” rationale for exploring space.  The dominant theme of his television series Cosmos was the vastness of the universe with endless possibilities for finding life “out there.”  For a public television program, it was a huge hit (but to keep some perspective, in 1980 when the series first aired, it did not crack even the top thirty, which included such fare as Dallas, The Dukes of Hazard, and The Love Boat).

Seeking to justify federal spending on space, the Quest for Life Elsewhere (QFLE, as I shall call it) was enthusiastically adopted by the scientific community.  As a slogan it was catchy, but effectively got nowhere in terms of policy influence until 1996, with the discovery of what was claimed to be bacterial microfossils in ALHA 84001 (a meteorite that on the basis of several lines of evidence, we believe comes from Mars).  This rock has tiny features that resemble fossil bacteria as seen in Earth rocks.  This discovery was considered sensational at the time and even resulted in a nationally televised Rose Garden statement by the President of the United States.  More significantly for policy, the Mars scientific community parleyed that discovery into a program series of robotic missions, each one increasingly more ambitious (read: expensive) to be sent to Mars over the coming decade(s).  This mission series was established outside the agency’s traditional lines of mission proposal and accountability systems and became (in effect), an “entitlement” for the Mars science community and JPL, who possesses the agency monopoly on missions to Mars.

A series of increasingly sophisticated spacecraft were then sent to Mars over the next few years, each one finding that the planet at one time had liquid water at or near its surface and that the climate of the planet has changed, perhaps many times, over the course of its history.  But no evidence of extant or former life has been found.  As portrayed in the article, this latest finding is another dashing of the “hopes” of the Mars scientists.  Funny – I always thought that the job of the scientist was to describe the universe as it is and how it works, not to “hope” for a confirmation of one’s preferred hypothesis (gained through the eyes of a machine afforded almost human-like adoration).

Which brings us to my point above about the use of QFLE as a rationale for the American civil space program.

Seasonal, or at least periodic, remote detection of Methane in the tenuous martian atmosphere may be evidence of biotic activity [ESA].

The goal of adopting such a rationale is to ensure an enduring, long-term space exploration program.  From a practical perspective, the danger of using QFLE as the primary goal for space is that if you do not find life, you’ve essentially failed and have probably written your programmatic obituary.  To date, the Mars science community has pled for a verdict of incomplete – we simply have not yet gone to the correct place with the correct tools and techniques to verify what they “hope” to find.  If this rationalization works, Mars exploration becomes an endless program – we can always say this, no matter wherever we go on Mars and whatever we find.  In fact, the problem with that rationale is that such pleading may backfire.  When most people think of alien life, they have images of ET in mind, not pond scum.  If the public understood that’s what we are really looking for, I suspect that a lot of the support for this crusade would quickly dissipate (I believe much of it has already).

My objection to using the QFLE as a rationale for space is on a more philosophical level.  Even if you finally do find martian microbes, what have you proven?  There are virtually no modern scientists who do not (to some degree) subscribe to the materialist paradigm of life’s origins, in which given the right compositions, energy and environment, life will naturally arise and evolve.  This is what scientists believe about the Earth and they most certainly believe it about other planets.  So if we finally do find Mars microbes, either ancient or existing, all we would have done is to prove something that most scientists believe now anyway.  The stridency of many scientists in their obsession to obtain “proof” of extraterrestrial life seems like other agendas are at work here, which I pass over without comment.

In science, new findings come all the time and it is highly likely that this “negative” result will soon be countered by some new and compelling “evidence” to the contrary.  I think that a long-range strategic rationale to explore and use the Solar System requires re-thinking.  A space program needs to return societal value for its cost.  I believe that there is abundant value in making our near-term goal the creation of a flexible and permanent system that opens up space for many different and varied uses.  Making the space program a Quest for Life Elsewhere is a prescription for failure and ultimately, termination..

Originally published September 24, 2013 at his Smithsonian Air & Space blog The Once and Future Moon, Dr. Spudis is a senior staff scientist at the Lunar and Planetary Institute. The opinions expressed are those of the author but are better informed than average. 

A Cheap Date

The MoonRise mission concept, in its most recent iteration, in cooperation with the Canadian Space Agency. The mission should fulfill a need to obtain a baseline sample of the 4 billion year-old South Pole-Aitken basin, only a small part of which spills over onto the Moon's nearside in line of sight with flight directors on Earth [NASA/NLSI].

Paul D. Spudis
The Once and Future Moon
Smithsonian Air & Space

  

Returning samples to Earth for analysis is one of planetary sciences’ holiest of grails. Although many different, complex measurements on returned samples are possible, one of the most important ones – from the standpoint of geologic study – is to determine the age of a rock.  Ages are determined by obtaining precision measurements of the amounts of different isotopes of certain elements (some of which are radioactive and decay at known rates).  By comparing the ratio of these radioactive elements to their daughter products, the amount of time that has elapsed since the rock formed can be calculated and thus, the age of that rock can be inferred.  If we know from which regional unit the rock comes, we can infer the ages of major events in planetary history.  This is one of the principal reasons why planetary scientists crave samples from other worlds.

We’ve determined the ages of most of the more than 380 kg of rock and soil samples returned from the Moon during Apollo.  Using that information and the geological mapping of the Moon from photographs, we were able to deduce the time sequence of major lunar and Earth-Moon system events.  Broad-scale, regional relations determined by remote mapping allowed us to identify the relative timing and significance of major units, while the returned rock samples allowed us to assign absolute ages to those same units.  The method proved so effective in reconstructing lunar history, that sample return became an idée fixe of the planetary science community, who strongly desired applying this approach to another planet.  Because questions surrounding its potential as a reservoir of life and because its nature permits the landing, retrieval and return (barely) of samples, Mars, with its complex, well mapped surface geology, was the object of most immediate interest.

When the planetary community wrote its recent “decadal survey” (a report outlining the highest priority robotic missions to undertake in the coming ten years), sample return came in as the highest priority for Mars (so high, that in effect, the decadal study told NASA to do a Mars sample return or do nothing).  Once Mars sample return was studied in detail, cost became an issue.  NASA robotic missions are classified according to the cost category they fall under.  The most expensive missions are “Flagship” missions, whose costs exceed $2 billion (the current MSL “Curiosity” rover Flagship mission cost about $2.6 billion).  A Mars sample return would require not one but three separate Flagship-class missions: one to rove and collect the samples, another to launch the samples into orbit around Mars, and finally a mission to collect those samples from Mars orbit and return them to the Earth.  Using a variety of scenarios, the effort would cost over $10 billion, with a possible price tag exceeding $20 billion.  This staggering cost quickly shelved Mars sample return while planetary scientists scrambled for something to fill in a possible multi-decadal gap with no mission.

The question became, “Can a different and cheaper approach begin to address some of the key issues for which sample return is thought to be essential?”  Although many kinds of measurements can be done on returned samples, radiometric dating is one of the most critical and one thought to be possible only in laboratories on the Earth.  By using the absolute age of a single unit to bracket the timing of a host of different units mapped from remote sensing data, a single rock from a surface outcrop of a clearly defined unit of regional significance might enable us to calibrate the geologic time scale of Mars.

So the question before us is, “Is it possible to measure the absolute age of a rock remotely?”

Several groups around the country have been investigating the possibility of creating a small, portable laboratory for radiometric dating.  These instruments could be miniaturized and flown aboard a future robotic rover.  Rocks could be selected for analysis as the vehicle roams across the planet.  If such a rover were sent to areas of known geological context (e.g., a large, regional lava flow), rocks dated by the rover would define an absolute age for the flow.  A large lava flow would have numerous impact craters on it (the more densely a surface is cratered, the older it is).  For Mars, we now have to estimate (i.e., guess) how old its units are by comparing crater densities with those for lava flows on the Moon (from which the Apollo astronauts returned samples).  Although this approach is better than nothing, Mars has had its own cratering history and direct comparison to lunar history may not be valid.  A few solid absolute ages for lavas of widely varying age on Mars could “tie down” the cratering curve, such that we would not only date the flows we visit, but we could with precision, confidently estimate the ages of many other geological units not visited.

Indicative of a healthy and engaged science community, not all are convinced that ages obtained from an automated lab would be as useful as the high precision results that would be obtained from state-of-the-art terrestrial laboratories.  But a collection of imprecise ages from a variety of different units on Mars is better than no dates from any unit at all.  Given the astronomical costs and high technical risk of robotic sample return from Mars, the idea that we might be able to measure ages remotely looks increasingly attractive and practical.  This technique could also be applied to other planetary objects.  A properly equipped rover could make numerous measurements of the ages of craters and lava flows over a wide area on the Moon, where such information could be tied into the existing high-quality (but incomplete) lunar time scale.  Remote age dating would also be useful on planets from which launch of a sample return vehicle is nearly impossible, such as Venus (with a dense atmosphere and a very high surface gravity).

As sample return missions escalate in cost and difficulty, we should investigate how much can be learned about a planet’s history short of sample return.  A properly equipped robotic rover could blaze a new “Lewis and Clark Trail,” traversing large distances and making precision measurements along the way – returning information of inestimable value for a relatively low price.

Originally published at his Smithsonian Air & Space blog The Once and Future Moon, Dr. Spudis is a senior staff scientist at the Lunar and Planetary Institute. The opinions expressed are those of the author and are better informed than average.

Related Posts:
How the Mars community shot itself in the foot (March 10, 2012)
LROC: The Soviet lunar sampling missions (March 16, 2012)
The Last Sampler: Failure, then Success (March 17, 2012)
LROC: Retracing the steps of Apollo 15 / Constellation ROI (April 17, 2010)
The Rosetta Stone of the Solar System (November 19, 2009)
The Keepers of the Moon (July 8, 2008)