There was a time when the words “space exploration” could only mean one thing: the highly competitive, secretive space race between the U.S. and the Soviet Union. They were the only powers that were really doing anything in space, and their efforts were tangled up in issues of politics, nationalism, militarism and other things which discouraged any spirit of cooperation. Now, those days are long gone. The Cold War has been relegated to the history books, and new powers are coming onto the stage of space exploration. The new spirit is one of cooperation, and the sharing of missions and the information that comes from them. While the possibility of space-based warfare is still uncomfortably real, there are now many other objectives for activity in space, and many new players to achieve them. One of these players is India, which has a growing space program that doesn’t get much PR in the states. The Indian Space Research Organisation (ISRO) is doing some fine work that should be recognized, and certainly will do much more in coming years.
India’s space program is not exactly new. For some years now, the ISRO has been launching some outstanding Earth-orbiting satellites, some for astronomy and some for observing the Earth itself. In all of our discussions about the exploration of other bodies in the solar system and beyond, we should never forget the importance of understanding our own world. Study of the mysterious third planet is of vital importance -literally- and those who contribute to it certainly deserve our respect. (More on this in future articles.)
This time, however, we will take a look at India’s Chandrayaan-1 probe, which is in orbit around our own moon, and has helped to provide some amazing information about the presence of water there. The implications of this are obvious: without a local source of water, there will never be a permanent human presence on the moon. The cost of transporting a steady supply of water from Earth to the moon for a long period of time would be astronomical (pun intended) and would make even a small colony prohibitively expensive. But if there’s already water there, it’s a whole new ball game. Suddenly we’re talking about the possibility of permanent colonies, which might eventually become independent political entities. With water, the moon can become a world in itself.
Chandrayaan-1 was launched on October 22, 2008 from Satish Dhawan Space Center, in Sriharikota, Andhra Pradesh. It was carried into Earth orbit onboard India’s Polar Satellite Launch Vehicle, and first entered a highly elliptical orbit in which the perigee (nearest point to Earth) was about 255 km. and the apogee (farthest point from Earth) was about 22,860 km. Using its Liquid Apogee Motor (LAM), the probe performed a series of course adjustments, moving into higher and higher orbits, and finally entering a 100-km. orbit around the moon.
The satellite was roughly cuboid in shape, about 1.5 meters on a side. It weighed 1380 kg. at launch and 675 kg. at lunar orbit. (Weight decrease due to fuel expenditure.) Electrical power for all phases of the mission was provided by a single solar panel with a peak output of 750W. This solar array was stowed on the south deck of the spacecraft during the launch phase, and deployed after exit from the atmosphere. During eclipse, the satellite was powered by lithium ion batteries. For orbital maneuvers, it carried a bipropellant integrated propulsion system with enough fuel for a two-year mission, with adequate margin.
It was designed to do high-resolution remote sensing of the moon in visible, near-infrared (NIR) low energy x-rays and high-energy x-ray regions. (with high spatial and altitude resolution of 5-10 m.) of both the near and the far side of the moon.
Chandrayaan-1 also carried a lander, the Moon Impact Probe (MIP), which was deployed when lunar orbit was achieved. The MIP hard landed on the lunar surface and conducted various explorations. In a moment of symbolic significance, the Indian tricolor was planted on the moon: one of Earth’s oldest cultures moving forward into the future.
In a true spirit of international cooperation, Chandrayaan-1 carried 11 scientific instruments contributed by India, the U.S., the U.K., Germany, Sweden and Bulgaria.
The actual mission has now been completed, and Chandrayaan-1 has moved to a 200-km. retirement orbit around the moon- but the fun is just beginning, because the data sent back by the probe and its lander will be analyzed for years to come.
As we said earlier, some of this information has now given strong indication of water on the moon. A few months ago, radar data from Chandrayaan-1 and also from two NASA spacecraft, the Deep Impact probe and the Lunar Reconnaissance Orbiter, indicated that there is a thin layer of water, only a few molecules thick, on the lunar surface. Scientists are theorizing that these meager traces of water may be evaporating and re-condensing in a “hop-scotching” pattern that causes them to move toward the lunar poles, becoming more concentrated as they go. There are craters at the poles that are permanently shaded, and have not felt sunlight for eons. Here, it is thought, the water may be concentrating and freezing.
You are probably shaking your head with disbelief as you read these words. We have been taught for so long that the moon is a dry, inactive world, that we now find it hard to believe that there is an ongoing process of water movement there. Granted, these water molecules are so few and scattered that you wouldn’t even be aware of them if you standing on the lunar surface, but if this process is happening all over the lunar surface, and if the water really is collecting in those polar craters, the amounts could be very significant, indeed.
But where is this water coming from? Is it seeping up from underground deposits? No, while underground deposits of water may also exist on the moon, the layer of molecules that we’re talking about now is apparently being made in an ongoing natural process. Carl Pieters of Brown University has suggested that it may be caused by the solar wind, which is constantly slamming hydrogen ions into the oxygen-rich rocks.
Think of the implications; water is actually being made on the moon. That means there will always be more of it. It’s not like a mineral, which exists in a finite amount and can eventually be exhausted. It’s a renewable resource.
The evidence for lunar water continues to mount. A news release at the NASA website dated March 1, 2010, says that analysis of data from a radar device which was designed by NASA and carried aboard Chandrayaan-1 has revealed more than 40 permanently-shaded craters near the lunar north pole which exhibit reflective qualities consistent with water ice. While the amount of water depends on how thick it is, scientists are estimating that there could be at least 1.3 trillion pounds of water in those craters.
The release quotes Paul Spudis, principal investigator of the Mini-SAR experiment at the Lunar and Planetary Institute in Houston: “The emerging picture from the multiple measurements and resulting data of the instruments on lunar missions indicates that water creation, migration, deposition and retention are occurring on the moon. The new discoveries show the moon is an even more interesting and attractive scientific, exploration and operational destination than people had previously thought.”
This is exciting stuff, and there is much more to be learned. India is moving onto the stage of planetary exploration, and will do much more in the years to come. Chandrayaan-1 is just the beginning- but a very good one. Thanks to the groundwork that was laid by Chandrayaans and the other lunar probes, it now appears certain that in time, permanent settlements, possibly of considerable size, will exist on the moon.
In connection with this, there is a small but significant political note that should be made. Only last week, President Obama announced that putting humans on the moon in the near future should no longer be a priority for our nation. He is absolutely right. Exploration and settlement should be our long-term goal, but not our short-term goal. In the short-term, there is much more to be learned from unmanned space probes, on the moon and various other locations in the solar system, and a human moon expedition would be a waste of money that could be spent doing more valuable research. We will go back to the moon, and eventually our descendants will live there, but before we get to that point, there is much to be learned from great unmanned projects such as Chandrayaan-1.
Sources:
“NASA Radar Finds Ice Deposits at Moon’s North Pole; Additional Evidence of Water activity on Moon” at NASA website: nasa.gov/home/hqnews/2010/mar/HQ_10-055_moon_ice.html
“Chandrayaan-1, India’s First Scientific Mission to the Moon” (mission webpage) at website of Indian Space Research Organization: isro.org/Chandrayaan/htmls/home.htm
“Chandrayaan-1, India’s First Scientific Mission to the Moon- Mission Sequence” at website of the Indian Space Research Organization: isro.org/Chandrayaan/htmls/mission_sequence.htm
Partain, Gary: “The Moon May Be Wetter Than We Thought” at Associated Content: associatedcontent.com/article/2232581/unexpected_water_on_the_moon_results_pg3.html?cat=15