So that they could see out of the spacecraft's window which, when they were seated, was directly over their head.
No, mercury is not used in mirrors. Mirrors are typically made with a glass sheet that is coated with a thin layer of silver or aluminum to create the reflective surface. Mercury is toxic and not suitable for use in mirrors.
why do we use concave mirror as converging mirror
Whatsimple and compound machines do astronauts use?
Probably most of them did at some point. You may be thinking of Alan Shepard who is well known to have wet himself while waiting for his Mercury flight to launch through many delays. Astronauts wore diapers for the reason that it is not always easy or possible to use the 'waste disposal system', and this did not even exist in the very earliest missions.
As there is no air , it is difficult , but astronauts use radios.
Astronauts on the moon used radios to communicate with mission control and other astronauts. The distance to Earth was too great for them to communicate in real time without radios. Additionally, the space suits and helmets they wore made it difficult to communicate verbally with each other.
Astronauts use DC electric power produced by fuel cells.
astronauts use space pen because as there is 0gravity in space ink will not fall on the paper
astronauty
a space belt
A concave mirror :)
It depends on what mirror are you looking at. If you use a plane mirror it will be in the same size but if you use the mirror in the car you will see a bigger image.