Geologists have recently determined that the minerals goethite and hematite exist in abundance on Mars, sure signs of the presence of water (see Figure 1 for a picture). None of those geologists have been to Mars, of course, but the unmanned rovers Spirit and Opportunity have. These rovers are equipped with three mass spectrometers, each of which is capable of determining the chemical composition of a solid with a high degree of accuracy. With such a precise chemical analysis in hand, geologists on Earth had no problem identifying the minerals.
A mineral is defined in part by a specific chemical composition. In theory, therefore, it is always easy to identify a mineral, if you can determine the chemical composition with a mass spectrometer like the Mars rovers. In reality, however, even if you are looking at rocks on Earth, determining the exact chemical composition of a substance involves significant time preparing the sample and sophisticated laboratory equipment (and often significant money). Luckily, it is usually unnecessary to go to such lengths, because there are much easier ways that require little more than a magnifying lens and a penknife.
The biggest design innovation that SpaceX has pioneered is, of course, the fact that Dragon 2 is partially reusable, potentially resulting in a significant cost reduction. The first stage of the spacecraft is capable of re-entering the atmosphere and landing vertically after separating from the second stage.
How does the shortage of water affect the community?
What are ways we can avoid water shortages?
How water shortages can be prevented?
What you should do if a water shortage happens?
The Volga river is the largest river in Europe, so that should be the answer.
