What does it mean by unmanned space missions?

The unmanned space missions are those using the remote-controlled spacecraft. The first such mission was the Sputnik I mission, began on October 4, 1957. Few missions are more appropriate for unmanned missions rather than manned space missions, as a result of lower cost and lower risk factors. Because the early 1970s, most unmanned space missions have been based on space probes with the built-in mission computers, and as such possibly will be classified as embedded systems.

What do you mean by De-oxygenation tower?

The oxygen must be removed for the reason that it encourages certain bacteria to grow. If a bacterium grows in the oil it will block the absorbent rock in the oil reservoir. The filtered water drops into the de-oxygenation tower spraying onto different trays causing gases to be released. The gas is sucked out of the tower with space pumps and the water fills the bottom of the tower. The de-oxygenated water is taken by boosting pumps to the high pressure water inoculation or the injection pumps.

Multithreading in Java

Java provides built-in support for multithreaded programming. A multithreaded program will have 2 or more parts that can run concurrently. Each part of such a program in java is called a thread, and each thread defines a separate path of execution. It is a specialized form of multitasking. There are two distinct types of multitasking namely Process-based and Thread-based.