MARS CORRECT BASIC REPORT - SECTION 13.6
Pressure Drop as MSL Climbs Mt. Sharp vs. Scale Height Predictions. This page updated on 9/15/2018.
13.6. Pressure Drop as MSL Climbs Mt. Sharp vs. Scale Height Predictions.
This Section correlates Mars Science Laboratory (MSL) pressures claimed with altitude in meters below areoid, the Martian equivalent to sea level. The data was originally published by the REMS Team, who work for JPL and NASA. They often read this report and may in fact be in rebellion to NASA as I write add this section to our report. This is suspected because until March 20, 2017 when the REMS Team published ludicrous data they generally went back and revised it – often after reading the critiques that are found in links provided in our enhanced daily Martian weather reports at http://marscorrect.com/cgi/wp/?page_id=622. But after March 20, 2017 the ground temperature lows became insanely cold and were not matched by air temperature lows. The REMS Team ceased making changes, leaving us to guess as to what was going on. We explain this later in Sections 15.6 through 15.6.2.at http://marscorrect.com/photo5_14.html.
For now let it be known that the REMS Team and NASA come here many times each week to both check on how their results are being received, and at times to see where they need to alter those results in an effort to draw less criticism. They even withdrew all their (never changing) wind data after we contacted JPL’s public relations man Guy Webster and they altered their Gale Crater Mars sunrise and sunset times to match my son David’s calculations. David has applied to work for NASA several times, but so far they only choose to read everything we publish, but make no offer – probably in part because our emphasis is always on scientific accuracy rather than political correctness.
Before going any further it should be noted that we have seen the numbering of MSL years is not always the same as what we refer to on our enhanced daily weather at http://marscorrect.com/cgi/wp/?page_id=622.. We label the first year of MSL on Mars as Year 1, but in at least one article we have seen it was referred to as Year 0. However we all agree on the Martian sols (days). On our charts Year 1 began at landing on August 5 to 6, 2012. It lasted 669 sols (until June 24, 2014). Year 2 then began, ending on Sol 1,338 on May 11, 2016. We are currently in the fall of Year 3. As I write this article MSL, in the southern hemisphere of Mars, is in the fall season. We have at least 1,733 sols of data minus some critical data for the first 10 sols, and for a few other periods of time. The first look at data comparing some Year 3 and Year 2 is given here as Table 17. Note the small amount of variation in pressure differences. There are 14 sols shown for each year segment. Six of them show pressure differences of 11 pascals (Pa) from one year to the next. The average pressure difference was 11.57 Pa. The smallest difference was 10 Pa and the largest difference was 13.
Table 17 altitudes were derived from JPL at https://mars.nasa.gov/msl/mission/whereistherovernow/. It’s not as complete as we would like, but there are often 2 meter altitude curves that can be used for approximation of altitude. During Year 2 for this period between Ls 11 and Ls 18 altitude didn’t change by more than a meter – floating between 4,447 and 4,446 meters below areoid. But for Year 3 there was an increase in altitude from about 4,266 to 4,251 meters below areoid. So the Year 3 segment shown started about 181 meters higher than Year 2, and finished about 195 meters higher. Knowing this we can ask, in accordance with scale height calculations, Is it reasonable to have pressures in Year 3 about 11 Pa lower than they were at a lower altitude in Year 2?
TABLE 17 above: Pressure and altitudes for MSL Years 2 and 3 between Ls 11 and 19.
Figures 58 above - Map of Gale Crater with Aeolis Mons rising from the middle of the crater. The MSL landing ellipse is in the northwest corner, about 4,500 meters below areoid. The landing was under 2.5 km from the target.
In looking at whether the data is reasonable, or apparently fudged as often seemed to be the case with REMS until about March 20, 2017 (when the REMS Team, aware of our critiques, seemed to go into a rebellion mode) we will want to look at variations in pressure using a scale height calculation to see if the approximately 9 Pa pressure differences each year line up with these pressure differences. More important, we will look at the 11 Pa difference between Year 2 Ls 11 and Year 3 Ls 11.
During Year 2 the pressure slowly climbed from 859 Pa to 867 Pa (actually reaching 868 Pa the sol before the end point on Sol 1,057). So the rise during this part of MSL Year 2 was about 8 to 9 Pa. Note that the pressure rose rather than fell but the altitude didn’t really change by more than a meter from sols 1,041 to 1,056.
For Year 3 the pressure rose again, this time (sols 1,711 to 1,725) from 848 Pa to 855 Pa (actually reaching 857 Pa the sol before the end point on Sol 1,726). So that’s a rise of about 7 to 9 Pa for Year 3 – quite similar to what was seen for Year 2 but here the rover is clearly climbing to where average air pressure should be lower if we do not consider seasonal changes.
In MSL Year 1 for this period pressures ran from about 866 Pa up to 875 Pa. Again, that’s an increase of 9 Pa between sols 374 and 389, but I have not yet been able to find altitude contour maps from that period, so I can’t yet definitively comment on how altitude and pressure were, if at all, linked for those sols. However a JPL image shows the rover locations from landing through this period, and it doesn’t look like it was more than from about 910 to 1,300 meters from the landing site (about 4,500 meters below areoid). See Figure 58 above to get a feeling for altitudes at Gale Crater.
The expected pressures for altitudes 4,500 meters/4.5 km (Year 1), 4,447 meters/4.447 km (Year 2) and 4,266/4.266 km to 4,251meters/4.251 km below areoid (Year 3) are given on Tables 18A (for a scale height of 10.8 km) and Table 18B (for a scale height of 11.1 km). On Table 18A column K provides a ballpark estimate for how to account for the fact that pressures given are for Ls 11 which is not when maximum pressure occurs. Under Column L highlighted in white numbers with a red background is the amount of pressure drop at Ls 11 from Year 2 to Year 3.
| TABLE 18A - PRESSURE CALCULATIONS FOR ALTITUDES DISCUSSED ABOVE USING A SCALE HEIGHT OF 10.8 KM | ||||||||||||
| A | B | C | D | E | F | G | H | I | J | K | L | |
| KILOMETERS | 10.8 km | RATIO A/B | =-EXP(C value) | 1/D value | PRESSURE | PRESSURE | PREDICTED | INITIAL PREDICTED | TIME & LS | ADJUSTMENT | FINAL PREDICTED | |
|
| Scale |
|
|
| MARS BARS | IN | PRESSURE | DROP IN PRESSURE |
| FOR NOT BEING | DROP IN PRESSURE | |
|
| Height |
|
|
|
| MBAR | IN PA | IN PA FROM |
| AT MAX PRESSURE LS | IN PA FROM | |
|
| (Mars) |
|
|
|
|
|
| YEAR 1 LS 11 & PREVIOUS ROW |
| 859/925.307 = .9283405 | YEAR 1 LS 11 | |
| MEAN AREOID 0 | 10.8 | 0 | -1 | -1 | 1 | 6.1 | 610 |
|
| 566.287705 |
| |
| -4.5 | 10.8 | -0.416666667 | -0.65924063 | -1.516896796 | 1.516896796 | 9.253070458 | 925.3070458 | N/A | YEAR 1 LS 11 | 859.0000055 | N/A | |
| -4.447 | 10.8 | -0.411759259 | -0.662483744 | -1.509471001 | 1.509471001 | 9.207773109 | 920.7773109 | 4.529734933 | YEAR 2 LS 11 | 854.7948692 | 4.205136392 | |
| -4.266 | 10.8 | -0.395 | -0.673680039 | -1.484384191 | 1.484384191 | 9.054743565 | 905.4743565 | 19.83268934 (15. 30295 from Year 2 Ls11) | YEAR 3 LS 11 | 840.5885168 | 14.20635234 | |
| -4.251 | 10.8 | -0.39361111 | -0.674616356 | -1.482323977 | 1.482323977 | 9.042176261 | 904.2176261 | 21.08941968 (1.2567304 from Year 2 Ls 11) | YEAR 3 LS 18 | 839.4218431 | 1.166673674 | |
| TABLE 18B - PRESSURE CALCULATIONS FOR ALTITUDES DISCUSSED ABOVE USING A SCALE HEIGHT OF 11.1 KM | ||||||||||||
| KILOMETERS | 11.1 km Scale | RATIO A/B | =-EXP(C value) | 1/D value | PRESSURE | PRESSURE IN | PREDICTED | INITIAL PREDICTED | TIME & LS | ADJUSTMENT | FINAL PREDICTED | |
|
| Height (MARS) |
|
|
| MARS BARS | MBAR | PRESSURE | DROP IN PRESSURE |
| FOR NOT BEING | DROP IN PRESSURE | |
|
|
|
|
|
|
|
| IN PA | IN PA FROM |
| AT MAX PRESSURE LS | IN PA FROM | |
|
|
|
|
|
|
|
|
| YEAR 1 LS 11 & PREVIOUS ROW |
| 859/925.307 = .9283405 | YEAR 1 LS 11 | |
| MEAN AREOID 0 | 11.1 | 0 | -1 | -1 | 1 | 6.1 | 610 |
|
| 566.287705 |
| |
| -4.5 | 11.1 | -0.40540541 | -0.66670647 | -1.49991045 | 1.499910449 | 9.149453737 | 914.9453737 | N/A | YEAR 1 LS 11 | 849.3808457 | N/A | |
| -4.447 | 11.1 | -0.40063063 | -0.66989746 | -1.49276579 | 1.492765785 | 9.105871287 | 910.5871287 | 4.358244991 | YEAR 2 LS 11 | 845.3349103 | 4.045935334 | |
| -4.266 | 11.1 | -0.38432432 | -0.68091056 | -1.46862167 | 1.468621674 | 8.958592213 | 895.8592213 | 19.08615241 (14.72707419 from Year 2 Ls 11) | YEAR 3 LS 11 | 831.6623974 | 13.67251293 | |
| -4.251 | 11.1 | -0.38297297 | -0.68183133 | -1.46663839 | 1.466638391 | 8.946494183 | 894.6494183 | 20.29595536 (1.20980295 from Year 2 Ls 11) | YEAR 3 LS 18 | 830.5392883 | 1.123109076 | |
Figure 49 - Comparison of scale heights in THE MARTIAN CLIMATE REVISITED and on a NASA web site.
What’s immediately noticeable about Tables 18A and 18B is that the pressure calculated for the landing site altitude matches the maximum pressure (925 Pa) that NASA/JPL/The REMS Team permitted the public to see after they altered the data – in large part in response to higher pressures that they first published which were challenged by us. Earlier Table 3 in Section 2.4 of this report listed most of the changes. For the sake of brevity here, Table 19 only presents pressures that were revised by NASA when they were originally published as being over 925 Pa.
| TABLE 19 – Pressures over 925 Pa revised by JPL/REMS after we highlighted them or published them in earlier version of our Report | ||||||
| Date | MSL Sol | Ls | Initial Pressure Reported | Pressure for the previous sol | Final Pressure Reported after JPL Revisions | |
| Sept 1 to Sept 5, 2012 | 26 | 164 | 742 to 747 hPa 74200 to 74700 (Pa) | 743 Pa | 745, 743, 745, 747 and 747 Pa | |
| Feb 19, 2013 | 192 | 267 | 940 Pa – a high until now. Pressures had been declining since a high of 925 Pa in late January 2013. | 921 | N/A | |
| Feb 27, 2013 | 200 | 272 | 937 Pa | 917 Pa | N/A | |
| Aug 21, 2013 | 370 | 9 | 1,149 Pa | 865 Pa | 865 Pa | |
| Nov 10, 2015 | 1160 | 66 | 1177 Pa | 898 Pa | 899 Pa | |
| Nov 12, 2015 | 1161 | 66 | 1200 Pa | 899 Pa (revised) | 898 Pa | |
| April 2, 2016 | 1300 | 131 | 945 Pa | 753 Pa | 752 Pa | |
| April 3, 2016 | 1301 | 131 | 1154 Pa | 753 Pa (2 sols earlier, 751 Pa on Sol 1302 | 752 Pa | |
| Oct 27, 2016 | 1502 | 249 | 928 Pa | 903 Pa | 907 Pa | |
Table 19 is evidence that that there is an agenda to keep pressure reported for MSL either at or below the 925 Pa indicated by the scale height calculations on Table 18A and 18B.
As can be seen from Figure 60, a maximum pressure of 925 Pa was seen in MSL Year 1 at Ls 252 and 253 (Sols 170 &171). In MSL Year 2 this same pressure was attained at Ls 257 (Sol 846). If, for the moment, we overlook the 925 pressure maximum allowed by JPL or whoever is behind the data alteration, then it should be noted that Table 17 only deals with pressures produced in MSL Year 3 between Ls 11 and 19. At Ls 11 in Year 1 the pressure given by the REMS Team was 866 Pa. This is about 92.83405% of the maximum pressure of 925 Pa (actually, 925.307 Pa) Now let's use that figure to look at what happened from Ls 11 in Year 2 to Ls 11 in Year 3. There was an increase in altitude of 181 meters and a decrease in predicted pressure of about 15.30295 Pa (Table 3A, cell H8-H9), but the actual NASA-claimed decrease in pressure was only 11 Pa. However, if the proportional idea is correct and we take 92.83405% of the predicted drop of 15.30395 Pa, then we revise it to a predicted pressure drop of 14.206 Pa. That's quite close to the 11 Pa supposedly measured (5 sols later there was a 13 Pa decrease from Year 2). The predicted and measured differences are clearly in the same ball park, but does this mean that NASA is correct - or does it mean that the data was manufactured by someone who knew how to calculate scale height?
Now, let's dig a little deeper here via modern textbooks (Figure 59). The Martian Climate Revisited use a scale height of 10.8, old sources use 11.1 and this figure is on the NASA webs site visited. The information looks old, mentioning Viking 1 and none of the landers since 1976. What happens if we assume that someone was tasked with predicting, i.e., manufacturing pressures for MSL based on the altitude change from MSL Year 2 to Year 3? Then the predicted pressure decrease (with Ls 11 factored in) becomes only 13.67 Pa! A Pascal is only a hundredth of a millibar. We see that on 4 sols between Ls 11 and Ls 18 the actual pressure drop from Year 2 to Year 3 was 13 Pa.
NASA only sent a pressure transducer that could measure up to 1150 Pa yet, as Table 19 shows, they often reported pressures above 925 Pa, and even above 1150 Pa only to revise them down when we challenged them. Thus there is reason to question the reliability of the data reported. NASA returned to our site to view the CAD for the pressure transducer used on Mars Pathfinder. This CAD (shown as Figure 10B - See http://marscorrect.com/images/correct_10b.png), is often visited by other space agencies too. What it shows is that two transducers were ordered by NASA for Pathfinder. Tavis – 2 was for the expected pressure range of 0 to 12 mbar (1200 Pa/0.174 PSIA). But the other transducer (Tavis -1) was designed to measure up to 1,034 mbar (103,400 Pa/15 PSIA). That's higher air pressure than is found at sea level on Earth.
While we hope our audit of NASA data will lead to organizational reform rather than any kind of legal action, if it ever does go legal then the first thing we would subpoena is documentation for what happened to that sensor. Did it really stay back on Earth, or was it secretly flown to Mars? Whereas Martian weather simply does not match the low pressures advocated by NASA, and especially because NASA has for a long time visited our web sites daily, we are confident that a full investigation will reveal that are we are again quite right, and that it's time for a new announcement from NASA indicating what the true pressure is there. See Annex G of this report for further details about the Tavis transducers ordered by NASA.
Figure 60 - Comparison of pressure readings by Viking 1, Viking 2, Mars Phoenix, and MSL.