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John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 1
Oil and natural gas on Mars
John F. McGowanNASA Ames Research Center
Mail Stop 233-18Moffett Field, CA 94035-1000
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 2
Outline of Talk
n Oil and natural gas on Earth and Marsn Instrumentation
• Ground Penetrating Radar• Trace Gas (Methane) Detectors
– Point Detectors– Open Path Detectors– Remote Sensors
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 3
Oil and natural gas
n Finding past life - even present life - onMars may be quite difficult.
n Need for a biomarker or biomarkers thatwill be widespread, easy to find andeasy to identify.
n Ideally, need to be able to detectbiomarker at a distance. Cannot visitevery square meter of Mars.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 4
Oil and natural gas
n Conventional theory holds that oil, coal,natural gas, and other subsurfacehydrocarbons are derived from past lifeon Earth.
n Far more carbon is stored in oil, gas,and other subsurface hydrocarbons thanin surface life.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 5
Oil and natural gas
n Nearly all oil and coal containsmolecules of biological origin - especiallyhopanoids, phytane, and sterane.
n Biological origin of hopanoids, phytane,and sterane is almost universallyaccepted.
n Sedimentary source rocks associatedwith natural gas contain the samemolecules and kerogen.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 6
Oil and natural gas
n Oil, coal, and natural gas are usuallyattributed to pressure cooking ofbiological debris over millions of years.
n Hopanoids derive from prokaryotes,simple single-celled organisms, notplants or animals.
n Oil is now attributed to simple organismsin rivers and seas, not plants andanimals.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 7
Oil and natural gas
n An ancient wet and warm Mars mayhave supported oceans, lakes, or riversteeming with microorganisms.
n Conditions for formation of oil, coal, ornatural gas may have occurred onancient Mars.
n Time frame is 3.8 billion years ago(Noachian Mars) to 300 million yearsago.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 8
Oil and natural gas
n An alternative theory holds that oil, coal,and natural gas are primordial.
n This theory almost certainly predictslarge quantities of oil, coal, or naturalgas on Mars.
n Some variants (e.g. Thomas Gold)propose that life originated in theprimordial subsurface hydrocarbons.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 9
Oil and natural gas
n Columbia River Basalt Group SLiMEecosystem is often suggested as amodel for current life on Mars.
n Natural gas was produced commerciallyat the Columbia River Basalt.
n SLiME proposed to produce methanen Methane seeps from a SLiME-like
Martian ecosystem seem likely.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 10
Instrumentation
n How to find oil or natural gas on Mars.• Ground Penetrating Radar• Trace Gas Detectors
– Point Detectors– Open Path Detectors– Remote Sensors
• Scanning IR Lasers• Passive IR Imaging Arrays
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 11
Ground Penetrating Radar
n Hydrocarbons have a dielectricpermittivity in range 2.0 to 3.0
n Water and water ice have dielectricpermittivity in range 2.0 to 3.0
n Martian regolith has dielectric permittivityin range 2.0 to 3.0
n GPR cannot unambiguously identify oiland natural gas
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 12
Trace Gas Detectors
n Detect CH4, H2S, H20, and other gases.n Unambiguously identify methane (CH4),
Hydrogen Sulfide (H2S), Water Vapor(H20), and other gases.
n Measure the concentration of CH4, H2S,H20, and other gases in the Martianatmosphere.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 13
Trace Gas Detectors
n Mars has winds (6-8 meters/second) thatwill carry gas from seeps far downwind.
n The Martian atmosphere has turbulentdiffusion that will spread the gas seepacross the wind and vertically.
n Thus, even a point trace gas detectorwill be able to detect a methane seep ata distance.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 14
Mobile Probes
n Mobile probes can carry trace gasdetectors and locate gas seeps of anyorigin.
n High Speed Rovers (1 meter persecond)
n Balloons (1-10 meters/second)n Airplanes (10-100 meters/second)
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 16
Mars Balloon
<- Retroreflector
Balloon with Open PathIR Trace Gas Detector
SURFACE OF MARS
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 19
Mobile Probes
n Usually have a science payload of 15-30KG
n Usually have a few hundred watts oftotal power (e.g. 200 Watts)
n Usually have a science payload volumeof order 100 cm by 100 cm by 100 cm(1,000,000 cm3) or less
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 20
Gas Seeps on Mars
n 0.34 KG/sec emission raten Gaussian Plume Modeln Distances in Metersn Gas Concentration in Parts Per Billion of
Earth Atmosphere at StandardTemperature and Pressure (STP)
n 1 PPB Earth = 1 x 10-9 KG/m3
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 21
Gas Seeps on Mars
n Wind velocity of 8 meters per second
n σ Y (Across Wind) = 0.04 x
n σ z (Vertical) = 0.04 x
n x is distance down wind.n This is a naive extrapolation of Earth
Gaussian Plume Models to Mars.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 25
Coverage of Mars (100 days)
Speed Range Coverage Percent
1 m/sec 100 m 1,728 km2 0.0012 %
100 m/s 100 m 17,280 0.12 %
100 m/s 1,000 m 1,728,000 1.2 %
100 m/s 10,000 m 17,280,000 12.0 %
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 26
Gas Seeps
n Probes should travel as close toperpendicular to the Martian winddirection as possible to achievemaximum coverage of the Martiansurface.
n Probes should travel as close to theMartian surface as possible to maximizethe likelihood of seep detection and thedetection range to a seep.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 27
Infrared (IR) Gas Detectors
Sensor Size Weight Power MDC Time
DFG 45 cm by45 cm by12 cm
25 KG 60 W 23 ppb 2.1 sec
Rosemount 22 cm by48 cm by48 cm
25 KG 150 W 1 ppm 0.5 – 20sec
ALIAS 200 cm by50 cm by50 cm
72 KG 400 W 50 pptv 10-30 sec
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 28
Mass Spectrometers (MS)
Sensor Size Weight Power MDC Time
ESS 53 cm by45 cm by23 cm
26 KG 170 W 2 ppb 100 msec
VikingGCMS
less than100 cm by100 cm by100 cm
much lessthan 600KG
much lessthan 140 W
10-50 ppm At least10.24seconds
VikingSpectraTrak
35 cm by52.5 cm by80 cm
66 KG 1300 W few ppm 10-15minutes
Galileo MS 18.4 cm(D) by 37cm (L)
13.2 KG 13 W + 12W
10 ppmvH2O
75 seconds
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 29
Current Trace Gas Detectors
n Are point or open path detectors.n In principle, scanning IR laser detectors
(active sensors) and passive IR imagingarrays (passive sensors) are possible.
n Scanning IR detectors and passive IRimaging arrays can detect gas plumes ata distance without relying on dispersionin the atmosphere.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 30
Current Trace Gas Detectors
n Too big, too heavy, too high power, tooinsensitive, or too slow for detecting gasseeps from mobile probes on Mars.
n Pretty close to needed parametersn “Faster, better, cheaper” mass
spectrometers and infrared detectors arebeing developed. Probably can bedeveloped to meet mission needs.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 31
System Requirements
n SIZE: 1000 cm3
n WEIGHT: 2 KGn POWER: 20 Wattsn RESPONSE TIME: 1 secondn Minimum Detectable Concentration
(MDC): 10 ppb of Earth atmosphere atSTP (about 1 x 10-8 KG/m3)
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 32
System Requirements
n Bit Rate: 4096 bits per secondn Bit Error Rate: 10-5
n Target Gases: Methane (CH4), otherhydrocarbon gases, Hydrogen Sulfide(H2S), Water Vapor (H2O)
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 33
Conclusion
n The Dream: The Probe detects a gasseep at a distance.
n The Probe navigates to the source of thegas seep.
n The Probe analyzes the soil at the gasseep and finds organic molecules suchas hopanoids that indicate past life oreven finds present life!
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 34
Oil and natural gas
n On Earth, most commercial oil and gasis 400 million years or younger.
n Several commercial fields areProterozoic (Precambrian)
n Oil seeps in 1.1 billion year old rocks inU.S. mines reported.
n Oil “shows” in Australia to 1.6 billionyears ago.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 35
Oil and natural gas
n Small amounts of oil reported preservedin “inclusions” in Archaean sandstonesfrom several sites to 3,000 million yearsago.
n Kerogen, presumed precursor of oil andgas, common in Precambrian rock.
n Kerogen reported in Isua rocks inGreenland (3.8 billion years ago)
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 36
Oil and natural gas
n Could oil or natural gas formed hundredsof millions or billions of years ago havesurvived to the present on Mars?
n Some studies indicate that oil can bestable under conditions of oil creation forbillions of years. Conversion to naturalgas requires higher temperatures thanpetroleum genesis.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 37
Oil and natural gas
n On Earth, sedimentation andmetamorphosis have been continuous.Few primordial rocks survive, e.g. Isuarocks in Greenland.
n Any ancient hydrocarbon deposits onEarth would have buried at great depthand pressure cooked into natural gas.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 38
Oil and natural gas
n On Mars, ancient rocks, e.g. 3.8 billionyears old, appear to survive nearsurface. An ancient oil deposit maynever have been buried at sufficientdepth to convert to natural gas.
n Martian volcanoes may have providedcaprocks to prevent outgassing of gasfields.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 39
Oil and natural gas
n Oil is ideal biomarker because it canseep to the surface and directly containsbiological molecules such as hopanoids.
n Natural gas is also a biomarker.However, it will not directly contain thebiological molecules. Must seekassociated sedimentary source rocks toprove biology.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 40
Oil and natural gas
n The easiest way to look for oil, coal, andnatural gas is surface seeps of naturalgas, primarily methane, and oil.
n No excavation.n No drilling.n Methane is less than 20 parts per billion
of Martian atmosphere. Methane seepwill be very obvious.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 41
Oil and natural gas
n Seeps of natural gas on Earth follow alog-normal distribution.
n Most seeps are small.n Some seeps are large. These seeps
dominate.n Coal Oil Point at Santa Barbara is an
example of a large seep (roughly 0.34KG/second of Methane)
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 42
Oil and natural gas
n On Mars, would try to find a large seep.n A large seep will be easiest to detect.n A large seep will probably represent a
large subsurface source of gas near thesurface.
n May find hopanoids or other biomarkersin the soil at the seep. Even oil onsurface may be possible.
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 43
Under Development
Sensor Size Weight Power MDC Time
TinyTOF 30 cm by15 cm by15 cm
5 KG 50 Watts ? ?
JPL (Sinhaet al)
? 1 KG 2 Watts ? ?
JPL(Chutjianet al)
10 cm by15 cm by20 cm
1.1 KG ? ? ?
Cassini-Huygens
? ? ? 10 ppb ?
John F. McGowan, Ph.D.E-Mail: [email protected] 7/28/00 44
Under Development
n Small solid-state Fourier TransformInfrared Spectrometer (FTIR), less than2 cm3,reported.
n Small solid state gas chromatographprototype, less than 2 cm3, reported.
n Further miniaturization of suitcase sizedIR prototypes (DFG) are possible.
