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The interior of Enceladus, a medium sized icy moon of Saturn hosts hydrothermal activity and exhibits tidal heating and related geyser-like activity. There are major disagreements in the existing literature on the porosity of the interior, due to the different theoretical assumptions on which porosity related calculations were based. We present an application of experimental equations - derived for Earth - for icy planetary objects and Enceladus in particular. We chose a set of boundary values for our initial parameters from measured porosity values of chondrite samples as references, and calculated the porosity related values of Enceladus using various approaches. We present a comprehensive investigation of the effects of using these different porosity calculation methods on icy moons. With our most realistic approach we also calculated the same values for Earth and Mars for comparison. Our result for Enceladus is a minimum porosity of about 5\% at the centre of the body. For the total pore volume we estimated $1.51*10^7 km^3$ for Enceladus, $2.11*10^8 km^3$ for Earth and $1.62*10^8 km^3$ for Mars. Using the same method, we estimated the total pore surface area. From this we derived that the pore surface under a given $1 km^2$ area of the surface on Enceladus is about $1.37*10^9 km^2$, while for Earth this value is only $5.07*10^7 km^2$., Comment: 8 pages, 9 figures

There may be a chance of small-scale ephemeral liquid water formation on present day Mars, even though the current climate does not support the existence of larger bodies of water. Through a process called deliquescence, hygroscopic salts can enter solution by absorbing water vapor directly from the atmosphere. Due to the absence of in-situ deliquescence experiments so far, the most reliable way to forecast deliquescence is through atmospherical modeling, however, the locations and times when salty liquid water could emerge are not yet well known. In this paper we present our results of likely brine formation on Mars, their proposed locations and seasons, as well as the possible limiting factors. For our calculations we used the data of Laboratoire de M\'et\'eorologie Dynamique Mars General Circulation Model version 5. The results show that from L$_s$ 35$^\circ$ - L$_s$ 160$^\circ$, between 9 PM and 11 PM there is a good chance for calcium perchlorate deliquescence above 30$^\circ$ N, while in this zone the ideal regions are concentrated mostly to Acidalia Planitia and Utopia Planitia between 1 AM and 3 AM. We found that in the Southern Hemisphere, between L$_s$ 195$^\circ$ and L$_s$ 320$^\circ$, there is a noticeable, but weaker band in the vicinity of 60$^\circ$ S, and both Argyre Planitia and Hellas Planitia show some chance for brine formation. According to our statistics the key limiting factor of deliquescence could be relative humidity in most cases. Our results suggest that during summer -- early fall seasons, there could be deliquescence in both hemispheres in specific areas from the late evening until the early morning hours. There are only few studies detailing the geological and temporal distribution of brine formation through deliquescence, thus this work could be used as a good guide for future landing site analysis or in choosing a specific location for further research., Comment: Accepted for publication in Icarus (arXiv version is Review 1, final version will be online soon on Icarus website)