Human Spaceflight In just 20 years, human exploration into space has made incredible

Human Spaceflight

In just 20 years, human exploration into space has made incredible strides.

In 1961, Soviet Cosmonaut Yuri Gagarin became the first human being to travel into space. On April 12 of that year, his Vostok spacecraft orbited the Earth once, then using a parachute that deployed 2.5 km above the planet and guided his re-entry.
The Vostok space craft was a sphere just 2.3 m in diameter with room for just one crew member. The entire mission took only 108 minutes, less than two hours.

Less than a month later, American Alan Shepard became the first American in space. His Mercury space ship entered space but did not orbit the earth. The flight lasted just fifteen minutes, but unlike Gagarin, whose ship was automatically programmed, Shepard navigated the entire voyage.

Twenty years later, the United States launched the first Space Shuttle, a vehicle designed an intended to be reusable for multiple flights. Unlike the early spacecrafts that used parachutes to "splashdown" in the ocean upon reentry, the space shuttle landed much like an airplane on a runway and could be refurbished and sent back into space on subsequent missions.

While the early space missions were measured in terms of minutes spent in space, the space shuttle was capable of staying in orbit for days. The longest flight was achieved by the Columbia Space Shuttle, which made a total of 28 flights, the longest of which was over 17 days.

While the space shuttle program ended in 2011, that does not mean the end of human exploration of space. Since the 1990s several private American companies have developed viable space exploration vehicles, and several organizations are exploring the notion of space tourism, which is not part of the mission of the US government funded program. Joint missions between the United States and countries such as Russia have continued the long tradition of exploring the frontier beyond the earth’s atmosphere.

What is the most effective way the author could improve the introduction to this essay?