In the Sreemad Bhagwat (3/32) the process of entering into the moon planet is mentioned as follows:--
"Materialistic men, who have no information of the Kingdom of God are almost mad after material acquisition of wealth, fame and adoration. Such men are interested in the progressive welfare work of the family unit for self-satisfaction and progressively extending the activities for social or national welfare. Such men do attain the desired object by material activities in the prescribed mechanical or ritualistic discharge of duties and are thus inclined to satisfy Pitris or the bygone forefathers and so also other controlling gods by performances of sacrifices as presented in the revealed scriptures. Addicted to such acts of sacrifices and ceremonial observances such men do enter into the moon planet after death. When a person is thus promoted to the atmospheric conditions of the moon he gets the necessary strength to enjoy the drinking of 'Somarasa' (a celestial beverage). The Moon planet is a place where the demigods like Chandra is the predominating deity. The atmosphere and amenities of life there are far more comfortable and advantageous than those what we have got to utilize here. And reaching there if a person does not utilize the opportunity to get promotion to other better planets, he is degraded and is made to come up again on this planet or any similar one like the earth. And such materialistic persons even though they attain to the topmost planetary system, do certainly get themselves annihilated at the time of periodical general disappearance of the cosmic manifestation.
So far as the planetary system in the spiritual sky is concerned there are unlimited number of Vaikunthas in the Paravyoma and the ratio is that the manifestation of the Lord's internal potency, that is the spiritual sky, is three times greater than that of the material sky made by the external energy.
Poor materialists are busy in political adjustment in a place which is most insignificant in the evaluation of God. What to speak of this planet earth the whole universe with innumerable planets up and down is compared with a grain of mustard amongst the mustards packed in a bag. Such poor materialists make plans here to live comfortably and thus waste most valuable energy of human life in a thing which is never to be completed. Instead of wasting time in that plan making business a plain and simple life with high thinking of spiritual life should have saved the misguided human being from perpetual unrest which is a gift of matter.
Even if a materialist wants to enjoy material facilities, he can transfer himself to the other many many material planets where he can experience more and more advanced material pleasures. The best plan of life is to prepare one self for going back definitely to the spiritual sky after leaving this body -- but yet if any one wants to enjoy the largest amount of material facilities, one can transfer himself in the other planets, not by means of playful sputniks which are simply childish entertainments but by psychological effects, and learning the art of transfering the soul by mystic powers. The yoga system is also materialistic in as much as it teaches to control the movements of air within the body. The spiritual spark, soul is floating on air within the body and breathing exhalation are the waves of that air containing the soul. The yoga system is a materialistic art of controlling such air which can be placed by practice of yoga from the stomach to the navel, from the chest to collarbones, from collarbones to the eye balls to cerebellum. And from the cerebellum the expert yogi can convey his own soul to any planet he desires. The velocity of air or light is taken into consideration by the material scientist but they have no information of the velocity of matter namely the mind and intelligence. We have some experience of the velocity of the mind because in a moment we can transfer the mind to lacs and crores of miles away. Intelligence is still fine matter. Finer than intelligence is the soul which is not matter at all but it is spirit or anti-matter and is crores and crores times finer and powerful than intelligence. We can thus make an imagination of the velocity of the soul and how quickly it can travel from one planet to another by its own strength without any help of any sort of finer material vehicle.
Animal's civilization of eating, sleeping, fearing and sense-gratifying has misled the modernised man and they have forgotten how powerful a soul he is. As we have already described that the soul is a spiritual spark which is many many times illuminating, dazzling and powerful than the sun, moon or electricity. Human life is spoiled by not realising his real identity. And Lord Shri Chaitanya Mahaprabhu along with Nityanand appeared to save the man from the type of misleading civilization.
How the yogis can travel in all the planets of the universe is also described in the "Bhagwatam" as follows:--
cerebellum there is every chance of this force being burst out from any one of the holes like eyes, noses, ears, as these are the places which are known as the seventh orbit of the vital force. The yogis therefore can block out these holes by complete suspension of passing air and carefully the yogi concentrates the vital force in the middle position or in between the eye brows. At this position the yogi can think of in which of the planets he wants to go after leaving this body. He can decide either to go to the abode of the Krishna in the Vaikunth which are transcendental places where nobody is required to come back again in the material world or at least if he desires not to go directly to the planets of the spiritual sky but wants to have a travel over the higher planets in the universe, he is at liberty to do so in that position.
For a perfect yogi who has attained success in the system to leave this material body in perfect consciousness, the process is as easy as an ordinary man in life time goes from one place to another. As already discussed the material body is just a covering of the spirit soul, mind and intelligence is the under cover and gross body of earth water air etc., is the overcoating of the soul. As such any advanced soul who has realised himself by the yogic process or the linking up process from matter to spirit -- can leave these shirting and coatings of the soul in perfect order as he desires. One has complete freedom by the grace of God. The Lord is kind upon us that we can live anywhere either in the spiritual sky or in the material sky and in any planet fixed up thereof. Misuse of this freedom makes him fall down in the material world and live in a conditional life full with three fold miseries. To live a miserable life in the material world is a choice of the soul as it is nicely illustrated by Milton's "Paradise Lost" poetry and not of chance and from the material world also by his own choice he can go back to home, back to God Head.
So in that critical time of placing the vital force in between the two brows, he is to decide where he wants to go. If he is completely reluctant to keep any connection with the material world, he can do so and within less than a second he can reach the transcendental Vaikunth and appear there completely in spiritual body just suitable to him in the spiritual atmosphere. He has simply to desire to leave the material world both in finer and grosser forms and then put on the vital force on the topmost part of the skull called Brahmarandhra. That is the highest perfection of practising yoga system.
But as he is endowed with the freedom of will and as such if he does not wish to get himself completely freed from the material world but enjoy a life of Brahmapada or occupy the post of Brahma and to see the place of materially perfect beings called the SiddhaLoka where a living being has full capacity of controlling the gravity, space, time, over Lordship, etc., then he has not got to leave the mind and intelligence (finer matter) but can simply give up the grosser matter and thus go up to the highest place of the material universe.
The sputniks or the so-called man-made planets made of mechanical arrangements will never be able to carry human being in the inter-planetary outer space. Even they cannot go into the so much advertised moon. The reason is repeated again in the higher planetary system the atmosphere is different from here. Each and every planet has its particular atmosphere and if one wants to go to any particular planet any where within the material universe one has to get his material shirt and coats made up exactly adaptable to the climatic condition of that particular planet. It is just like this. If a person wants to go from India to Europe where the climatic condition is different from India, then one has to change his dress accordingly. Similarly complete change of dress as much as we require to change the body when we want to go up to the other transcendental planets of Vaikunth.
The difference is that if we want to go to the highest material planet we need not change the finer dress of mind intelligence and ego but we have to change the gross dress made of earth, water, fire, etc.
But when we go to a transcendental planet we require to change both the finer as well as gross bodies and we have to reach in the spiritual sky completely in spiritual forms. The change of dress will automatically take place simply by desiring it at the time of death. This desire is possible only if we practise it during the constant state of life. Such desires when practised in relation with material world, are called fruitive actions. When such desires are conducted in relation with the kingdom of God, it is called divine or devotional service which is discussed also in this issue.