The chandra x-ray observatory must operate in space because:

a) x rays are too dangerous to be allowed on the ground.
b) x rays do not penetrate earth's atmosphere.
c) x-ray telescopes require the use of grazing incidence mirrors.
d) it was built by nasa.

B) X rays do not penetrate Earth's atmosphere

Explanation:

The Chandra X-Ray observatory should operate in space due to the nature of the radiation it is using. X-rays are high energy electromagnetic radiations. The observatory will not be able to function properly since it uses x-ray because, the rays cannot penetrate the earth's atmosphere. A radiation of this type would easily be cut off by the particles in the atmosphere. The observatory has to be positioned outside of the earth.