After Viking

If you asked most people what NASA was doing on Mars, the answer would be “looking for life”. NASA has been very careful to nurture that idea by talking about “the search for Life on Mars”. However what NASA is actually doing on Mars is not searching for life. NASA is conducting a wide variety of geological investigations to characterize the history of Mars’ rocks. It is not actually looking for any signs of life, and in fact, has not flown any instruments capable of detecting life since Viking.

It has looked for water and it has tried to build an understanding of the ancient history of Mars to determine if, and for how long, Mars had oceans, rivers and lakes. But it has not directly attempted to detect life.

In the years since Viking, NASA has returned to Mars frequently. In addition several orbital missions, NASA landed on Mars with the Pathfinder, Phoenix, Spirit, Opportunity and Curiosity missions. One additional mission failed to land (the Mars Polar Lander). Each of those missions had a scientific lead who was a geologist, an atmospheric scientist or a physicist — Dr. Matthew Golombek (Geologist, Pathfinder / Mars Exploration Rovers [Spirit & Opportunity]), Dr. Peter Smith (Physicist / Optics, Phoenix), Dr. John Grotzinger (Geologist, Curiosity), and Dr. Richard W. Zurek (Atmospheric science, Mars Polar Lander). The most visible NASA scientist engaged in Mars research has been Dr. Stephen Squyres (Planetary Scientist, principle investigator for Spirit and Opportunity).

The experiments carried on these vehicles can be divided roughly into three categories:

Environmental — These instruments measure winds, temperatures, air pressures, dust, and the component gasses in the Martian atmosphere. Optics — These instruments take pictures from panoramic vistas to microscopic close-ups of rock surfaces and drill sites. Spectroscopic — These instruments are designed to detect the chemical makeup of rocks using lasers, nuclear particle detectors, and analysis of gasses emitted when samples are heated.

Compare those experiments with Viking:

Biological Detection — Samples of Martian soils were heated, treated with nutrients, and mixed with radioisotopes to attempt to detect any biological processes in the samples. Environmental — all the routine measurements you would expect. Optics — the first pictures of the Martian surface were transmitted by the landers using panoramic cameras. Spectroscopic — Viking had a gas chromatograph which was used to determine the types of material in the Martian soil.

Since Viking, NASA has never flown instruments capable of detecting biology on Mars.

NASA’s next big Mars mission, Mars 2020, will be lead by Dr. Ken Farley, a geochemist. It is a rover mission with a chassis derived from Curiosity. It carries no experiments designed to detect biology.

The Viking Controversy

Prior to the landings, NASA’s scientists had defined various criteria for each of the experiments that they would use to determine if they had detected life on Mars.

According to those rules, two of the experiments succeeded in detecting biological processes, one was inconclusive, and one found no evidence of biology.

NASA decided that the results of the experiment that had failed to detect life overrode the results of the other experiments and the official conclusion was that Viking had failed to detect life on Mars.

The issue was that the experiment that showed “no life” also seemed to indicate that there were no organic compounds in the soil at all. So NASA’s analysis was that the successful detection of biology in the other two experiments had to be due to unknown factors other than biology.

The Surprising Discovery of Phoenix

The Phoenix lander arose out of the ashes of the Mars Polar Lander (pun intended by NASA) after the MPL suffered a malfunction when it attempted to land on Mars. Phoenix was fast-tracked by using a lot of left-over hardware from the Mars Polar Lander and an earlier aborted Mars lander project to quickly make a new craft that could replicate some of the MPL mission’s goals.

Phoenix arrived on Mars in 2008. In the course of its investigations it discovered that the Martian soil contained an unexpected component — the chemical perchlorate. Up to that point, nobody knew that perchlorate was common on Mars.

Perchlorate is, as its name suggests, a compound including chlorine. When heated, perchlorate can decompose, releasing chlorine gas. It seems likely that what happened inside the Viking lander was that when soil samples were heated for gas chromatography the process liberated enough chlorine to essentially sterilize the test chamber. In other words, in the process of testing the soil samples for biology, the test itself might have destroyed any traces of that biology, which means that test should be invalidated, leaving two successful experiments and one inconclusive result.

Viking appears to have found experimental evidence for life on Mars.

Meanwhile, at Jupiter and Saturn

The two Voyager missions to the outer planets revealed the moons of Jupiter and Saturn in wondrous detail. And one of the findings NASA made was that some of those moons likely harbor vast subsurface oceans.

The moons are far enough from the sun that sunlight cannot heat them enough to liquify water. But they are in orbit around huge planets and are affected by the gravity of those planets as well as that of the other moons. The result is that gravitational and tidal effects stress the moons, creating heat at their cores. That heat is sufficient to raise their temperatures above water’s melting point.

Europa, one of the four largest moons of Jupiter, was the first moon that seemed likely to have oceanic quantities of water. Voyager photos showed an icy white surface that was not marked with craters but instead was ruffled with thousands of cracks and rills. Since all the airless bodies of the solar system have been bombarded for billions of years by meteors and comets and all show substantial cratering, the lack of those features on Europa implies that its surface is regularly recycled by some process that removes the evidence of those impacts. It is likely that Europa’s surface is ice, not rock.

The Galileo and Cassini follow-up missions to Jupiter and Saturn provided even more data on the icy moons. In addition to Europa, subsurface oceans are now thought likely to exist beneath the rocky crusts of Ganymede, Callisto, and Enceladus. Enceladus regularly vents huge plumes of water from its poles which rise hundreds of miles above its surface. Saturn’s moon Titan is even more interesting, possessing an atmosphere and oceans of hydrocarbons.

Every 10 years the national science community prepares a recommendation of the projects that the Federal Government should fund. In the most recent “decadal” survey, a mission to explore Europa was the 2nd mostly highly recommended mission. Despite that, NASA elected not to pursue a Europa mission, and withdrew from a potential partnership role with the European Space Agency on a joint mission to explore Jupiter’s icy moons. NASA appears uninterested in attempting to fly a mission to Enceladus to capture samples of the water it is venting into space. It landed a probe on Titan, but that probe contained no instruments designed to detect any biological process.

This matter became so egregious that Congress stepped in. In NASA’s most recent funding, an exploration mission to Europa has been mandated. It is the only mission that NASA is legally obligated to undertake — and the agency still drags its feet on preparing to plan and fly that mission.

What is Going On?

The taxpayers expect that NASA is looking for life in the solar system. It seems like finding life would be the ultimate success for the agency, leading to unparalleled scientific benefit and unknowable social benefit — we already derive surprising drugs & industrial compounds from creatures found in rain forests and extreme environments here on Earth, so there’s no way to predict what kind of value we could derive from extraterrestrial life forms.

NASA clearly understood that in the Apollo era. Viking was a product of that time, as was Voyager.

NASA is not looking for life in the solar system.

What happened?

Nixon, Reagan & the Cold War

When Richard Nixon became President in 1968, the cost of the Vietnam War, LBJ’s Great Society, and the Apollo Project were on a collision course. The budget had to be cut. Nixon closed the “gold window” and ended the Bretton Woods system that had governed global finance since WWII. Inflation started to spiral out of control and interest rates and unemployment began to rise.

NASA had ambitious dreams post-Apollo. All of those dreams were compromised as its budget was slashed. The tail end of the spending it had acquired during Apollo paid for the three crews to fly to Skylab, and for Viking and Voyager, but that was the end of the glory. NASA was forced to pick from all of its projects one program to continue and it chose the Space Shuttle on the theory that with the Shuttle it could lower the cost to get to orbit and that could induce Congress to fund a range of other projects.

Reagan inherited an over-budget Shuttle program that was deeply compromised by deals that NASA had made with the Department of Defense to secure Congressional approval. Instead of reducing the cost to get to orbit the Shuttles actually cost substantially more to operate than the Saturn V that was the workhorse for Apollo and Skylab. When Challenger disintegrated the Reagan administration resigned itself to the knowledge that the Shuttle would fly less frequently than planned and at a higher cost than planned. Public support for NASA reached all-time low points — clearly there would not be much money available for other projects.

NASA’s dream of an orbital space station languished for most of the Reagan years because the costs involved were simply too high. After the Cold War ended, giving Russian spacecraft engineers something useful to do besides sell their skills to rogue nations became a national security priority, and Russian space tech was, all things considered, pretty good. Combining NASA and the Russian Space Agency’s space station efforts into one program produced the International Space Station, which subsequently also went substantially over budget and delivered far less than its boosters promised, but it did get built (at a cost of over $100 billion).

This massive expense in human spaceflight meant that NASA’s funding for planetary sciences was crushed. Very little progress was made in the 1980s except for the Voyager missions that had launched in the 70s. However in the 90s, under the Clinton administration, the scientists at NASA fought for and won funding to restart NASA’s solar system explorations. The people who did that work were almost all physicists and planetary scientists, and their agendas dominated the science planning for those missions. Success begets success and now NASA’s planetary scientists dominate all the key leadership positions in the organization related to mission planning and experiment selection.

Missteps and Circuses

The biologists in the NASA community did themselves no great favors.

Lots of people were hoping that Viking would find life on Mars. When NASA’s official pronouncement was that there was no life on Mars, and in fact it was unlikely that life on Mars was even possible, the public lost interest in the Viking project. By raising excitement about the idea, then dashing those hopes, NASA’s Mars project shot itself in the foot.

In 1996, NASA scientist Dr. David S. McKay published a paper in Science and triggered a series of NASA press conferences where he described organic shapes detected inside a meteorite with Martian origins. The work remains intriguing but in general the scientific community remains skeptical of these claims as the supposed “microbes” are smaller than any known life-form ever found on Earth, and there are reasonable non-biological explanations for the appearance of the structures McKay found in his electron microscope.

In 2010, NASA scientist Dr. Felisa Wolfe-Simon claimed in a paper in Science that she had isolated a colony of bacteria that used arsenic instead of phosphorous as a part of fundamental biochemical processes. It was “life, but not as we know it”. By extension she was arguing that we could be looking for life elsewhere in the solar system in the wrong way by focusing on the chemistry of earthlike life forms. By 2012 the claims had been soundly refuted and Wolfe-Simon’s reputation was destroyed.

These missteps create a very challenging environment for biologists inside of NASA. Arguing with official NASA pronouncements about Viking got the lead scientist for one of the experiments that seemed to indicate that it had detected life blackballed from the NASA community. The web of relations between grad students, research projects and co-published papers means that people associated with Drs. McKay and Wolfe-Simon are somewhat tainted by their association even if they did not work directly on either of those problematic papers. In the normal battle for authority within any scientific community, the biologists are at a substantial disadvantage within NASA.

We Need a Hard Reset

For whatever reason the biologists are not getting their payloads onto Mars landers. And NASA is not interested in flying missions to the icy moons to investigate their potential for life.

This has to change.

Congress needs to step in and take action to put “looking for life in the solar system” at the center of what NASA does with its budget. Second only to monitoring Earth to understand global climate change, the search for life in the solar system needs to be NASA’s paramount exploration goal.

NASA needs a biologist with equal institutional rank and power as the planetary scientists. It needs to assign biologists to be the principle investigators for future Mars lander missions and for exploration of the icy moons.

If a house-cleaning needs to be done to get entrenched but compromised biologists out of the NASA community, then it is time to do that housecleaning. If new biologists need to be recruited with ironclad guarantees that their work will be promoted and that their experiments will fly, then those promises need to be made & kept. 40 years of waiting shows that NASA’s entrenched bureaucracy is incapable of making these changes so it will require political will to do it. Similar will was exerted by the Obama administration to force NASA into the Commercial Resupply and Commercial Crew agreements for the ISS. A future administration needs to be ready to do the same for biology.

There is no project more likely to justify the public’s investment in space than finding life in the solar system. The detection of such life then justifies a wide-ranging follow up program that could include crewed flights to continue to investigate those ecosystems. NASA’s activities which are now random and lack direction would quickly gain a unification of purpose the agency has lacked since Apollo 17 left the moon in 1972.

The Case for Life in the Solar System

NASA has gotten one thing right: Looking for life means looking for water. Until we find something so wholly unlike terrestrial biology that it justifies a change in strategy, NASA needs to focus its efforts on places where liquid water exists in substantial quantities.

We know there is liquid water on some of the icy moons of Jupiter and Saturn. We can’t imagine how life would exist on Titan, but it’s thick atmosphere and liquid hydrocarbon oceans are intriguing.

We believe there is liquid water in some amount beneath the surface of Mars, and we know there was liquid water there in the distant past. We also know that methane gas has been detected on Mars. That is notable because methane breaks down naturally in sunlight after just a few decades, so some process must exist to continuously renew it, and a biological process is a good candidate.

There is a chance that the Dawn mission to Ceres will detect a liquid water ocean there, in the heart of the asteroid belt (which is particularly notable because doing science at Ceres is substantially easier than doing it in the harsh environment of Jupiter, the distant moons of Saturn, or even the tricky conditions on Mars.)

Life in the solar system may be common. And it may be earthlife. We know that cosmic collisions transmit material between the planets — we have found meteoric rocks from Mercury, Venus, and Mars through that process. It’s likely that most bodies in the solar system have been hit by rocks blasted off of the Earth in long-ago collisions — rocks likely “contaminated” by bacteria and viruses. Earth may have been “spamming” the solar system with DNA and microbes for billions of years. It need not require some miraculous lottery-ticket to find life elsewhere in the solar system; indeed we may be surrounded by our distant cousins.

It is very likely that we can get samples of soil and gasses from these locations and subject them to tests to see if there are any traces of biology in them. We have the technology to do those missions now — we need not wait to fly those missions. An emphasis on cost containment and very narrow mission parameters should control the budget.

The Europeans, Russians and Indians have flown missions to Mars. The Chinese are learning how to operate deep space missions on the moon. The time when NASA will have a monopoly on the ability to fly missions to find life in the solar system — and the resulting benefits to American taxpayers that could result — is closing. We should be capitalizing on a 40 year head start to stake our claims to this potential now.

Let’s figure out what it will take, and then make that happen.