Roffman Mars Research

Higher Than Advertised Martian Air Pressure

Part 1 – Basic Report Overview of Pressure Measurement Issues

David A. Roffman

Embry-Riddle Aeronautical University

DavidARoffman@GMail.Com

       The enigma of dust devils/storms on Mars with a near-vacuum pressure rated at 6.1 mbar at areoid is cause to question accuracy of accepted pressure values. The Basic Report includes reviews of NASA-archived historical documents, analysis of technical papers, personal interviews of pressure transducer designers, and a brief discussion of an in depth audit of Viking pressure and temperature data (see Annexes). Only four landers attempted to measure pressure – two Vikings, Pathfinder, and Phoenix. Accepted pressures are based on their data and radio occultation/spectroscopy by orbiters. Viking transducers were only rated at 18 mbar (Pathfinder and Phoenix at 12 mbar). Both Vikings showed consistent daily pressure spikes at the same times. They are highly correlated with how gas pressure in a sealed container would vary with Absolute temperature. Pressure fluctuations are linked to heating by radioisotope thermoelectric generators (RTGs). When the heaters were most needed there was less than a 2% difference for predicted and reported pressures. The formula employed assumes a clogged air access tube/dust filter.

       Radio occultation-derived pressures are discussed, as are Pathfinder and Phoenix wind speed measurement failures. Phoenix pressure transducer design problems are highlighted with respect to confusion about dust filter location, and lack of information about nearby heat sources due to International Traffic and Arms Regulations (ITAR). Further pressure questions arise from high densities encountered during aerobraking operations (particularly over the South Pole). Spectroscopy for pressure did not work over ice there. NASA could not replicate dust devils at 10 mbar without employing wind speeds 11+ times greater than associated with Martian dust devils. Spiral clouds with ~10 km-wide eye walls are seen on and over Arsia Mons where pressure was thought to be ~1 mbar. Future transducers require wider pressure range sensitivity and a way to replace dust filters and keep air access tubes clear. 

A quick set of links to Roffman Mars Research follow. Last year's presentation by David to the 13th International Mars Society Convention in Dayton, Ohio was updated this year at the Convention in Dallas on August 4, 2011 in accordance with the findings below. David's presentation was updated on November 29, 2011 due to important new discoveries about movement of Martian sands and 10 to 100 times more water vapor than expected in the Martian atmosphere. These findings back our claims of higher pressure.

PowerPoint Summary of HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE - Part 1 by David A. Roffman. Posted February 21, 2012.

PowerPoint Summary of HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE - PART 2 by Barry S. Roffman.  Posted August 18 2011.

BASIC REPORT for HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE. Updated August 16, 2011.

Higher Than Advertised Martian Air Pressure

Part 2 – Audit of Viking Pressure Data

 Barry S. Roffman (Lieutenant, USCG, Ret)

ArkHunt@Juno.Com

       After a cursory review of the Viking Project Data it became apparent that an extensive audit was imperative. The Viking Project Data did not seem to explain weather phenomena (spiral clouds over Arsia Mons, dust devils, etc.) clearly seen on Mars. A general discussion of the problems is offered in the Basic Report by David Roffman. The data audit results are presented in seven Annexes. The Viking Project data divides every Martian day into 25 time-bins (hours), each ~59 minutes long. Annex A (Viking 1 sols 1 to 350) and Annex B (Viking 2 sols 156 to 361) emphasize how pressures change during morning time-bins that correspond to 0630 to 0830. A simple formula, Pressure predicted = (6.51 mbar*255.77 K)/Temperature K measured, was often correct for 0730. Annex C examines how often the pressure sensor did not work (stuck or no pressures) between Viking 2 sols 639 and 799. Annex D examines the percent differences between hourly predictions and reported pressures for Viking 1 from sols 1 to 350. Annex E focuses on predictions and reported pressures for the 0.3 (0730) and .34 (0830) time-bins. Annex F maps out the best and worst prediction times each day, clearly proving the influence of the RTG heaters on hourly pressure reports. Annex G shows what went wrong in the transducer selection and testing process. These Annexes provide hard evidence that the Tavis pressure transducers used for the Vikings (and Pathfinder) likely jammed with dust during the landing process. The meaning of this is that it is doubtful that they ever measured ambient pressure conditions of Mars.  There is evidence that all subsequent attempts to measure pressure were colored by the reported Viking results. Problems with Phoenix pressures based on a Vaisala transducer are discussed in the Basic Report.

BASIC REPORT for HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE. Updated August 16, 2011.
 

Abstract of Audit of the Viking Project Pressure data and ANNEX A to HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE. Viking 1 Morning Pressure and Temperature Changes. Posted July 10, 2011.

ANNEX E to HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE.

ANNEX F to HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE.

PARTIAL YOUTUBE COVERAGE OF PART 1 OF DAVID ROFFMAN'S PRESENTATION TO THE MARS SOCIETY ON AUGUST 5, 2010.

YOUTUBE COVERAGE OF PART 2 OF THE 2010 MARS SOCIETY PRESENTATION   

Note: corrections about Dr. Ingersoll's positions last year are incorporated into this year's presentation.

Below: 14th International Mars Society Convention in Dallas, Texas (2011). Left to right: Pat Duggins, National Public Radio of Alabama; CNN Space Correspondent John Zarrella; Embry-Riddle Space-physics senior David Roffman; and author Barry Roffman