地空 and 地劫 are commonly grouped as members of the 六煞星 (6 Sha Stars) consisting of: 擎羊、陀羅、火星、鈴星、地空、地劫. This grouping in the system of ZWDS are known as the 兇星 (Malevolent Stars) and their appearances in any of the 12 Palaces of ZWDS usually raise special concerns and treatments depending on the configurations. As their names suggest, they usually connote bad qualities and hence not highly favoured. However, I would like to clear the misconceptions of most people that 地空 and 地劫 are to be treated as like the other Sha Stars. Most of the other Sha Stars are that of aggressive, destructive and evil nature, but this is not the case for 地空 and 地劫. Indeed these two “stars” are not even stars proper. They are traditionally grouped under the 空劫 stars grouping.
地空 and 地劫 should not be treated as any of the stellar bodies in ZWDS. Simply put, this group does not have astral origins. Rather, these two “stars” are of Earthly origins in its Yin and Yang extremities. It serves to extinguish/obliterate the influences of stellar factors in the palaces in the Birth Charts. The energy field is that of 兇煞 (Malevolent Sha), in which case the 煞 is representative of Positive Ions which are found in harsh, barren environments, usually harmful to or devoid of life. These “stars” are fluid 天羅地網 that binds and manipulates charts.
The elemental nature of 地劫 is that of Yang Fire. Its literal Chinese translation is “Earth Loss”, and it denotes the destruction and loss of the physical. Its earthly manifestations are in the mountains and the valleys.
The elemental nature of 地空 is that of Yin Fire. Its literal Chinese translation is “Earth Void”, and it denotes the loss and void of the mental. Its earthly manifestations are in the deserts and wastelands.
Contrary to popular beliefs that the appearance of these “stars” in the palace are harbingers of malice and misfortune, 地空 and 地劫 generally have function as geological black holes that negate all effects of good and evil stars in own and influenced palaces. If the palace has full of malevolent stars, with either of these two “stars” around, it may contribute to the negation of the effects of the other Sha Stars. However, they are generally still not considered favorable to be found in any palaces, because while they have the power to bring down the influences of the stars (good and bad), they will considerably gain power and the black holes might totally expend away whatever might be good to the palaces. Hence, these 地空 and 地劫 are still pretty much feared; while they are not malevolent, they can lead to much more destructive aspects to the natives, ranging from bankruptcy to utter failures, destitute and death.
A large part of how these two “stars” contribute to the destructive effects of the palaces are largely dependent on their elemental locations. While having either 地空 and 地劫 in any palaces are usually bad news, when they are in elemental locations that bring about their brightness to 廟旺, they will tend to be rendered less powerful. Their power will be stifled further if there also exist the presence of main stars and other support stars in full brightness. On the other hand, when they are in elemental locations that bring about their brightness down to the dark 落陷, their dark power will be maximal and usually such configurations tend to be not favorable to the natives. This is especially dire if the main stars and other support stars are equally dim, or if the presence of other minor 空 stars are around.
地空 will generally be 廟旺 in the 寅, 午, 戌, 已, 酉 and 丑 palaces, whereby their dark power will be rendered weak. However, in 甲, 子, 辰, 亥, 卯 and 未 palaces, their brightness has 落陷 into the darkness and that is where the black hole will take effect at its maximal strength. For 地劫 the only favorable elemental locations are in 辰 and 戌, the 天羅地網 oppositions. The rest of the other locations will bring about its darkest power and the greater destructions wreaked upon the stars.
Interesting Case: There is a saying from ancient sages that “火空則發、金空則鳴”, that when 地空 meets 火星 in 巳宮 or 午宮, and when gold elemental stars (e.g. 武曲,文昌) meet 地空 in 申 and 酉宮, it will bring about a powerful alchemical reaction. 火空則發 signifies massive explosion while 金空則鳴 is the loud alarm. The former can be regarded as a sudden windfall, or great fortune while the latter can mean great accomplishment and/or recognition. This is especially applicable when the 禄星 are visiting the aforementioned palaces. The encounter with 忌星 will lesser the effect of this star. However as of any associations with 地空 and 地劫, usually all the energies and positive/negative effects will eventually be drawn in and expended into the darkness of the black holes, to oblivion.