Model Tests for Exhaust Gas Contamination on Mars

The Mars environment is a challenging place to conduct experiments involving emissions from spacecraft. The LOX/CH4 system is capable of manufacturing propellant in the Martian atmosphere through electrolysis of its constituents. These engines would emit CO and H2O as exhaust gases. Such accidental releases of methane fuel could potentially confound the measurement of local atmospheric trace gases, which could prove problematic if human missions were conducted there. An example is a proposed Mars mission requiring 6 metric tons of methane fuel.


Vehicles contribute to the contamination of the atmosphere by releasing several toxic gases into the atmosphere. The primary source of these gases is the combustion of fuel and aggregates. Other sources of toxic gas emissions include spent crankcase gases and fuel fumes. Table 4 summarizes the composition of the toxic emissions in a car exhaust. There are several sources of pollutants in a car exhaust, including hydrocarbons, nitrogen oxides, and particulate matter.

Model test

A Model test for exhaust gas contamination can help determine the level of pollution in an automotive exhaust. The process starts with a sample that is obtained from the exhaust gas system. This sample is then preconditioned to meet the specifications of the measurement instrument. This preconditioning prevents any physical changes that may occur to the species that is being measured. Generally, measurement instruments operate at a temperature close to ambient, and it is important to cool the sample before use.

The model test for exhaust gas contamination consists of collecting samples from all the available exhaust ports. This sampling method enables the analysis of the pollutants, such as PM, as well as PAH and micro-ames. Its components include a constant volume sampler, dilution tunnel, sampling probe, and two filter holders in parallel. The system also has a flow meter and a controller. Once the exhaust is conditioned, it must be vented properly to avoid any damage to the engine or to the exhaust.

CFD analysis

To assess the dispersion of contaminants in the atmosphere, we used computational fluid dynamics (CFD) simulation. We assumed a k-e model with wall functions, and the governing equations were discretized using the finite volume method and a 2nd order spatial scheme. We also considered a range of environmental parameters including temperature and topography. Our model provided a more accurate representation of the dispersed contaminants than other existing models.

In this study, the turbulence in the atmosphere and the amount of SO2 released from the stack were simulated. We then developed a wind profile that replicated actual atmospheric conditions. The simulations revealed that SO2 dispersed within 500m of the stack. These results highlight the need for pollution control to minimize adverse effects on the surrounding community. The simulation results provide valuable insight into the design of a new stack, reducing the emission of harmful pollutants.

Effects of ice

The effects of ice on the composition of exhaust gases from vehicles are largely unknown. However, it is known that the use of dry ice in theater productions and fire extinguishers can increase indoor CO2 levels when the building is not adequately ventilated. The presence of high CO2 levels in the basement of a building is also a sign of poor air circulation. High levels of CO2 can affect health in people.

The research involved the Concordia Antarctic Snowpack Study, which yielded a year-long record of emissions of particulate matter and ozone. This allowed the scientists to determine which episodes caused elevated concentrations of different pollutants. They also used the sensitive chemical tracer NOx to identify exhaust plumes. The results provided new insights into the chemistry of these pollutants in snow and ice. While snow has been a useful way to measure emissions of particulate matter, ice can also interfere with the process of photochemical reactions.

Temperature on DOC

The temperature effect on DOC efficiency is an important concept in catalytic oxidation of CO. DOC is highly efficient in oxidizing CO at temperatures above the “light-off” temperature of catalytic activity. This temperature varies depending on exhaust composition, flow rate, and catalyst composition. In this paper, we will focus on the role of temperature in catalytic oxidation and present an effective strategy for raising DOC temperature during low-temperature operating ranges.

The effect of temperature on DOC was not expected to be significant in idle conditions. It is possible that the low exhaust temperature in idle would deactivate DOC. Sequential measurements of target VOCs and NMHC emissions demonstrated good precision within 5%. In contrast, sequential samples for CO2 and HC showed no differences. It is therefore important to study the effect of temperature on DOC of exhaust gas contamination.

Effects of retrorockets

In spaceflight, retrorockets slow a spacecraft down as it reenters the atmosphere. During lunar orbit insertion, a retrorocket fires to help slow the spacecraft down. A multistage rocket may use retrorockets to separate stages and slow the descent of the lower stage before reaching the ground. Retrorockets also serve as a reaction control system to slow the spacecraft down during reentry.

In a recent study, Viking rockets measured the effect of exhaust gas contamination on the atmosphere. They measured atmospheric composition and the presence of less abundant species. The Vikings set a 2-day limit for the contamination of soil by exhaust gas after landing, a timeframe they considered sufficient for gas diffusion. However, a small amount of wind movement may reduce the time limit. Because of these issues, retrorockets have received much attention in space flight.