Because of the low production volume of orbiters, the Space Shuttle program decided to build a vehicle as a Structural Test Article, STA-099, that could later be converted to a flight vehicle. The contract for STA-099 was awarded to North American Rockwell on July 26, 1972, and construction was completed in February 1978. After STA-099’s rollout, it was sent to a Lockheed test site in Palmdale, where it spent over 11 months in vibration tests designed to simulate entire shuttle flights, from launch to landing. To prevent damage during structural testing, qualification tests were performed to a safety factor of 1. 2 times the design limit loads. The qualification tests were used to validate computational models, and compliance with the required 1. 4 factor of safety was shown by analysis. STA-099 was essentially a complete airframe of a Space Shuttle orbiter, with only a mockup crew module installed and thermal insulation placed on its forward fuselage.
The largest, shining object in Earth's starlit night sky, our Moon has long been the source of mystery, myth, and poetry--a captivating inspiration for those who stare at the sky in wonder. But Earth's Moon is a very real object--the only body beyond our own planet that we have actually set foot upon, leaving our lingering footprints in its distant, alien dust. Earth's Moon has been with us almost from the very beginning, and even though it is our planet's closest companion in space, it has nonetheless managed to keep some of its ancient secrets very well. In September 2015, astronomers released a new study that shed light on Earth's bewitching companion's ancient and secretive past. Although our Moon now appears to be unchanging, as if it has always been exactly the same as it appears now--going through its beautiful and, yet, familiar phases, and controlling our ocean tides--in the distant past, things were actually very different. Christian folklore claims the Man in the Moon is Cain, the eternal Wanderer, doomed forever to circle the Earth. In addition, there is a Talmudic tradition that says it is the face of Jacob etched out on the gleaming lunar disk. Water in its life-sustaining liquid phase exists beyond our own planet, both in our Solar System--and elsewhere. With oceans of water sloshing around on 71% of our own planet's surface, Earth still remains the only planet known to have stable bodies of liquid water. Liquid water is essential for all known life forms on Earth. The existence of water on the surface of Earth is the outcome of its atmospheric pressure and a stable orbit in our Sun;s circumstellar habitable zone. The habitable zone is that Goldilocks region, surrounding a star, where the temperature is not too hot, not too cold, but just right for life sustaining water to exist in its liquid phase. However, the origin of Earth's water still remains unknown.