Data Debate with Professor Ingersoll of CalTech/JPL
Why there is "No Sale" on a NASA Mars expert's request that this study be terminated. (Updated 6/26/2014)
INGERSOLL'S FIRST CRITICISM: “The mechanism of dust devil lifting is uncertain, and is not a basis, of itself, for questioning the lander and occultation data.”
RESPONSE: The problem with the mechanism of lifting being uncertain relates directly to what the pressure is. The fact that pressure is believed to be so low, when paired with particle sizes estimated to be in the 1 µm range is why Read and Lewis (2004, page 190) estimated threshold velocities for particle life at greater than 500 m/s (1,118 miles per hour). Clearly, nobody believes that winds are moving anywhere near this fast on Mars. If modern science is ignorant about how such lifting can occur at more reasonable wind speeds, then it seems perfectly valid to use the dust devil phenomena on Mars as cause to start the inquiry. All the knowledge gained about lander equipment deficiencies and published in Section 2 (also http://marscorrect.com/photo2_4.html and http://marscorrect.com/photo2_5.html) of my Basic Report plus in Annex G to my report including dust filter and air port access problems on all landers, insufficient (or late) testing procedures for Tavis sensors, and ITAR problems that kept the Phoenix transducer designer in Finland from having critical design information related to heat sources and even the number and location of dust filters employed came after we began the thorough review based on the difficulty in explaining dust devil lifting. As such, we believe that this criticism is without foundation. As for occultation data, it is discussed in Section 5 of my Basic Report.
INGERSOLL'S SECOND CRITICISM: “The seasonal pressure changes recorded by VL-1 and VL-2 have been modeled to high precision on the basis of growth and decay of the seasonal polar caps. Your Figure 8 A-C (renumbered 9A-C below) ignores this agreement between theory and observation.”
RESPONSE: First, let us look again at the text and Figures in question from Section 2.1 of my Basic Report.
Perhaps most striking is what happens when there is a close examination of two graphs that sum up Viking-2 sol averaged temperatures and pressures. Figure 9A and 9C show that as pressure rose, temperature fell. To counter falling temperatures, RTGs kick on to maintain internal temperature stability. As this occurs, air trapped behind any dust clot would experience a pressure increase. When the Figure 9C graph is inverted and displayed as Figure 9B, the temperature and pressure graphs are nearly an exact match. The biggest discrepancy is after a hiatus with no data between Viking 2 sols 560 to 633 (Ls 68 to 100 in Martian spring to summer). An audit of the data showed that VL-2 pressure readings were often stuck for anywhere from 10 hours to six days (see Annex C for stuck pressures for VL-2 sols 639 to 799). Note that when pressures were stuck, temperatures were not.
Figure 9A to 9C: Graphs shown as Figure 9A and 9C are redrawn from Tillman and Johnson. Figure 9B inverts the direction of temperatures on the Y axis to show how heating by RTGs to counter increasing cold outside produces a curve very similar to the pressure curve.
OUR SECOND RESPONSE: You wrote that our "Fig. 8 A-C (renumbered 9 A-C) ignores this agreement between theory and observation.” “Perhaps, but you ignore the implications of what happened in Figure 8B. The data closely matches what would be expected to happen to a gas if heated or cooled in a closed container – out of touch with ambient conditions on Mars. We did not invent the graphs provided by Tillman and Johnson. Nor did we invent the gas laws.” As for the modeling, in all honesty I would have to study it. There have been changes over time in the estimation of how thick deposits of CO2 are at both poles. Further, as Tillman notes:
"The first minimum of pressure, about sol 100 (aerocentric longitude (Ls) 145) corresponds to the maximum amount of carbon dioxide sublimation in the south polar region, while the second, about sol 434 (Ls 346), corresponds to northern winter. Because of the elipticity of the Martian orbit, the difference in the semiannual heating and cooling produces this semiannual difference in the amount of carbon dioxide in the polar regions.”
With regard to the absolute minimum pressure seen by lander on Mars, we now have 4 Martian years of data for the time around Ls 145 – one for Viking 1, two for Viking 2, and one for MSL. The data can be summed up as follows:
| TABLE 8 – Pressures at Ls 90 and minimum pressures seen by VL-1, VL-2 and MSL | ||||
| Lander | Year | Mbar pressure at Ls 90 | Mbar Minimum Pressure | Ls of Minimum Pressure |
| VL-1 | 1 | N/A (7.51 at Ls 97) | 6.77 | 145 |
| VL-2 | 1 | N/A (7.72 at Ls 118) | 7.29 | 145 |
| VL-2 | 2 | N/A (8.06 at Ls 100) | 7.27 | 148.48 and 155.393 |
| MSL | 1 (2014) | 8.56 | 7.30 | 150 |
* Originally JPL published a pressure of 7.05 mbar for Sol 1 at Ls 150, and 7.18 mbar for Sol 9 at Ls 155, however they later changed these pressures to N/A. VL- 1 and VL-2 data from http://www-k12.atmos.washington.edu/k12/resources/mars_data-information/data.html.
Since there is no ocean on Mars to slow the time of maximum cooling it would seem like the coldest time in the southern hemisphere would be at Ls 90, yet we see that minimum pressures can occur over 65 degrees later as Mars moves through its 360 degree orbit of the sun. If the minimum pressure seen by VL-2 at Ls 155.393 is correct, that’s less than 25 degrees short of spring in the southern hemisphere at Ls 180. Frankly, we think this is a pretty lousy fit to the idea of carbon dioxide at the South Pole driving the pressure cycle.INGERSOLL'S THIRD CRITICISM: “If the average surface pressure were 2-3 times higher than assumed in the models, then the *percentage amplitude* of the oscillations would be less, and the agreement would disappear.”
RESPONSE: Please provide the math to support your statement.
INGERSOLL'S FOURTH CRITICISM: “In the discussion of Fig. 14 (now renumbered as Figure 17) you say "there should not be enough pressure to drive such storms." This is an unsupported assertion, and there are many “OTHERS.”
Sample Photo 2
INGERSOLL'S FIFTH CRITICISM: “The difference between VL-1 and VL-2 is explained by the altitudes of the two landers only if the average pressure for the whole planet is 7 mbar. If it were 20 mbar, then the difference between the two landers would be 20/7 times higher, which is not what they measured.”
Below: Sample page from Annex C showing no pressure changes.
Below: Sample page from Annex D showing many pressure changes less than the ability of Vikings to accurately measure due to digitization of pressure data and a 0.088 mbar pressure resolution capability.
Table 4 from our Basic Report. The resolution was only 0.088 mbar. Often this resulted in a pressure changes recorded of about 0.09 mbar.
INGERSOLL'S SIXTH CRITICISM: There is a lot of uncertainty about how dust is lifted from the surface of Mars, but a higher surface pressure is not the answer. Different methods agree within a few percent, so the surface pressure is well known. You would be better off trying to understand the mechanisms of dust lifting than trying to dispute the pressure measurements.
RESPONSE: So long as there is uncertainty, which goes with the nature of the universe, there is reason to question. Different methods to explain lifting does not mean that any of them are right. The low pressures do not easily or all explain the weather plainly seen on Mars. The fact that different methods for lifting agree within a few percent may mean nothing more than the fact that scientists are desperate to come up with models that justify bad data. This is like what we saw in history when so many people tried to come up with fancy ways to prove that the sun and planets circled the Earth. Their predictions may have been correct, but the fundamental beliefs were totally wrong.
SEVENTH CRITICISM: We have pressure measurements at the surface from Mars Pathfinder...
RESPONSE: Mars Pathfinder had the same (flawed) Tavis transducers as the Vikings had. Suppose we want to measure temperature. We have 2 thermometers - both from the same factory where a drunken worker labeled them as Fahrenheit when really they measured Celsius. We send them off to Mars, and they agree on the temperature. But they are wrong. Now we go back to the same factory and grab a third and send it off to Mars too. Lo and behold, it gives the same temperature. But it's still dead wrong. So with the Tavis transducers sent to Mars. Problems with Tavis transponders are addressed in detail in my report.
INGERSOLL'S SEVENTH CRITICISM CONTINUED: ... and Phoenix as well. The instruments on both Mars Pathfinder and Phoenix have calibration issues related to temperature variations, but all four sets of pressure measurements are mutually consistent at about the 1% level (after accounting for differences in surface elevation). It's very hard to believe that all four sensors could be biased in precisely the same way, so as to give the same wildly wrong answer. Here are a couple references.
Mars Pathfinder pressure measurements:
http://marscorrect.com/custom3_5.html
http://www.sciencemag.org/content/278/5344/1752.full
Phoenix pressure measurements:
http://www.agu.org/journals/ABS/2010/2009JE003422.shtml
RESPONSE: Thanks for acknowledging the calibration issues. Your first link to the Pathfinder pressure measurements will be discussed more on a separate page at http://davidaroffman.com/custom3_33.html. However, your first link mentions windspeed calibration problems. They were never solved by the Pathfinder team. I believe that their failure was likely caused by the failure to get the pressure right. This is discussed in Section 11.1 of our Basic Report.
Three of the 4 missions you mentioned used the same Tavis transducers. So the real issue is with respect to why the Phoenix had similar figures. It helps to understand what problems are known about the testing, deployment, and data intepretation for these sensors. Here a quick idea of some of the problems encountered can be gained from Section 2 (and it subsections) of our Basic Report. Certainly all the landers were subject to dust ingestion on landing.
NOTE: The following comments were written by David Roffman based on a 2009 Draft of the same paper that was just given as a link for Phoenix pressure measurements above at http://www.agu.org/journals/ABS/2010/2009JE003422.shtml.
With the interpretation of the data back on Earth I believe a real effort was made to make the data fit in with what was previously believed. The reason that I say this is that in the Abstract of ON PRESSURE MEASUREMENT AND SEASONAL PRESSURE VARIATIONS DURING THE PHOENIX MISSION (Oct. 2009 Draft by Peter A. Taylor et al.) it states that, "the original data processing routine had problems because the thermal environment of the sensor was subject to more rapid variations than had been expected. Hence the data processing routing was updated after Phoenix landed." They pointed to inaccuracy caused by unit temperature rises above 0° C in the afternoons. The paper includes plenty of phrases like, "We presently have concerns about the accuracy of our pressure data on diurnal and semidiurnal time scales and can only present preliminary results." The importance of what happened to the data after it got back to Earth is apparent from their remarks that, "Calibrated pressure readings are calculated after the data are transmitted to Earth.... The reason why the raw pressure data readings calculated onboard differ from the actual calibrated readings is associated with a lag of actual Barocap temperature relative to that reported by the Thermocap because of differences in thermal contact." Now, all this does not prove any kind of deliberate effort to fudge results. But it does show the complexity of what was attempted. However, when "calibrating" readings, there would be a natural tendency to try to make the final data fit in with what was known. There were many caveats in the Taylor et al. (2009 Draft) paper about how the data was collected for Phoenix. If Phoenix was not designed properly, we're back to three Tavis transducers - and the one on Pathfinder only functioned for less than 3 months (July 4th to September 27th, 1997). So, in terms of annual pressure changes, we only have the two Vikings - and as has been shown above, their pressure data was certainly flawed by great periods of no pressure fluctuation despite wild swings in temperature.
The questioning of the lander pressure data was not a flippant decision. The effort is now a 4-year one with a Basic Report and Annexes that are approximately 700 pages long. Concerns about our findings, suggestions for improvement, etc. should be sent to Barry S. Roffman at e-mail address MarsCorrect@Gmail.Com.