On May 5, 1961, Navy Commander Alan Bartlett Shepard, Jr., was launched into space from Cape Canaveral, Florida, in a capsule called Freedom 7. Shepard was the first American to travel to space. The flight took off at 9:34 a.m., and lasted just 15 minutes. In that short time, Shepard reached an altitude of 187 kilometers (116 miles) above the Earth.This launch was part of Project Mercury, an American effort to test humanity's capabilities in a space environment, as well as the conditions during and after a flight there. During his travel into space, Shepard and Freedom 7 passed through each level of the atmosphere: the troposphere, stratosphere, mesosphere, and thermosphere. In each level of the atmosphere, there are drastic shifts in pressure, density, temperature, and chemical composition.Freedom 7, as well as almost all spacecraft that came after, were single-use vehicles. Engineers working on the space shuttles, the only spacecraft designed for multiple use, used knowledge from early missions such as Freedom 7 to know more about the atmosphere and its layers in order to make shuttle missions safe.
Term Part of Speech Definition Encyclopedic Entry altitude Noun
the distance above sea level.
Encyclopedic Entry: altitude atmosphere Noun
layers of gases surrounding a planet or other celestial body.
Encyclopedic Entry: atmosphere density Noun
number of things of one kind in a given area.
Encyclopedic Entry: density mesosphere Noun
region in Earth's atmosphere between the stratosphere and the thermosphere, about 50-80 kilometers (31-50 miles) above the Earth's surface.
outer space Noun
space beyond Earth's atmosphere.
force pressed on an object by another object or condition, such as gravity.
vehicle designed for travel outside Earth's atmosphere.
level of Earth's atmosphere, extending from 10 kilometers (6 miles) to 50 kilometers (31 miles) above the surface of the Earth.
degree of hotness or coldness measured by a thermometer with a numerical scale.
Encyclopedic Entry: temperature thermosphere Noun
layer of the Earth's atmosphere located between 80 kilometers (50 miles) and 550 kilometers (341 miles) above the Earth's surface.
lowest layer of the Earth's atmosphere, extending from the surface to about 16 kilometers (10 miles) above.