Space Travel

By Kelvin Long
The history of space exploration is littered with achievements which are were the mere dreams of generations past. Rocket exploration began with the likes of Robert Goddard in the United States of America when in 1919 he published “A Method of Reaching Extreme Altitudes”. Meanwhile, work was underway in Germany with the likes of Herman Oberth who in 1923 published his work “The Rocket into Planetary Space”. This research led to inspiring other rocket engineers in Germany such as Wernher von Braun who during the Second World War developed the A4 rocket, also known as the Vengeance Weapon or V2.

Whilst the field of rocket science was advancing members of The British Interplanetary Society were meeting in England during the 1930s to discuss a credible engineering concept for travelling to the Moon. Although much of the theory for rocketry had been worked out by the Russian Konstantin Tsiolkovsky which he published in his 1903 treaties “The Exploration of Cosmic Space by Means of Reaction Devices”. But all of these developments were the warm up to the even more dramatic events that were to follow.

Sputnik-1

Sputnik-1, the first object launched into orbit by humanity on the 4th of October, 1957 - Image © Adrian Mann

On the 4th October 1957 the Russians surprised the World by the launching of Sputnik 1 satellite on an R-7 rocket known as the “Sputnik” rocket. The Sputnik 1 satellite was a spherical satellite, around 580mm diameter, and less than 100 kg in mass, and placed into an orbit hundreds of miles above the surface of the Earth, completing an orbit in around 96 minutes. History records that this event started ‘The Space Age’ and the competition between the United States and the Soviet Union.

The Americans first placed their own satellite, Explorer 1, into orbit using a Juno rocket, on the 31st January 1958. Although only around 14 kg in mass, it obtained the first measurements of the Van Allen radiation belts around the Earth.

Events moved rather rapidly from here on and then on the 12th April 1961 the Russian Yuri Alekseyevich Gagarin became the first human to travel into space outside of the Earth’s atmosphere, when he was launched on a Vostok-K rocket into orbit aboard the Vostok 1 spacecraft.

The first American in space was Alan Bartlett Shepard, Jr, and he made a sub-orbital flight on the 5th May 1961 aboard a Mercury space capsule launched on a Redstone rocket.

The competition for the Moon race was then initiated and in the U.S., through a succession of space programs, from Mercury, Gemini to Apollo, culminated in the first man walking on the surface of the Moon on 21st July 1969. This was the American Commander Neil Alden Armstrong and he was accompanied by his equally capable Lunar Module Pilot Edwin ‘Buzz’ E Aldrin, Jr. The Command Module Pilot Michael Collins remained in Lunar orbit as his two companions enjoyed the sea of tranquility.

Since the amazing days of Project Apollo, exploration in Earth orbit has continued, primarily with the building of Space stations and the location of orbiting satellites. The very first space station was the Russian Salyut 1, which operated from April to October 1971 and eventually had a crew on board for over 20 days, although sadly the crew died on reentry due to a pressure value opening prematurely. The Salyut 4 space station operated between December 1974 and February 1977 and hosted two separate crews, one for over sixty days. The Salyut 5 space station operated between June 1976 and August 1977 hosting three crews on board, for a total of 67 days. The Salyut 7 space station operated between September 1977 and July 1982 and hosted five different crews, the longest staying for 185 days. Salyut 7 operated between April 1982 and February 1991 and hosted 10 crews during its decade long life.

Eventually, the Russians developed the Mir space station, which operated between the years 1986 to 2001, a record fifteen years. Mir still holds the record for the longest continuous human presence in a structure in space for nearly ten years with a maximum of six humans occupying it at any one time. Mir was finally de-orbited in 2001 during a controlled re-entry. The early Russian experience in manned space stations was a valuable contribution to our understanding about how long humans can remain in the space environment.

The United States placed its first space station Skylab into orbit in 1973 and it was in use until 1974. The Skylab space station was built from a converted S-IVB upper stage of a Saturn IB and Saturn V rocket. During its time three different crews lived on board.

Today, the international community is focused on the final construction phase of the International Space Station (ISS). This is a joint enterprise with America, Russia, Canada, Japan and several European nations and has been permanently occupied since October 2000. This orbital platform stands as one of humanities greatest engineering accomplishments.

The key to the construction of the ISS has been the United States Space Transportation System (STS) otherwise known as the Space Shuttle. This elegant machine has inspired millions and kept the dream of spaceflight alive. There is a belief however, that humans are not yet ready for missions beyond the Earth-Moon system, although this thinking is slowly changing with the launch in 2010 of the US Administrations Space Exploration Initiative which at least has Mars within its sights at some future date.

So what about the robotic exploration of space? Many space probes have been sent to Venus, Mars, the gas giants Jupiter, Saturn, Uranus and Neptune as well as their surrounding moons. This includes Galileo launched in 1989 to explore the Jupiter system, and Cassini-Huygens, launched in 1997 to explore the Saturn system and included the deployment of the Huygens probe into the atmosphere of the moon Titan. These missions will likely continue in the near future as we discovery more about the planets that are in our own solar system, how they were formed and examine the prospects for life. There is also a mission currently on its way to the dwarf Planet Pluto, called New Horizons, and launched in 2006, it should arrive at Pluto in 2015 and continue on into the Kuiper belt.

In the decades past there have been many successes. This includes the Pioneer 10 and 11 probes launched by the United States I 1972 and 1973 and travelling at speeds typically 2.6 AU/year these 258 kg probes have passed the all of the planets in our solar system and head on out into the surrounding solar heliosphere. NASA also launched the Voyager 1 & 2 probes in 1977. With a mass of around 800 kg each and travelling at speed of around 3.5 AU/year, these probes have also crossed into the outer limits of our solar system out past any of the planets.

These robotic ambassadors are a testament to our engineering and dedication to the exploration of space. In the decades to come, more ambitious missions will be proposed, down into deep gravity wells, onto the surface of tortuous planetary surfaces, or far out into the cold dark depths of space. To accomplish these missions, engineers will need all of the technical resources they can muster, and politicians will need courage to authorise the funding for them. Because it is only the combination of these two elements, creatively bold designers and visionary politicians, but driven by a clear science goal, that will allow the more ambitious missions to be accomplished. Then humans can follow their robotic probes and begin the long march to human colonisation of the solar system – a necessary step before human interstellar missions can properly be addressed.

Kelvin LongKelvin Long is a physicist/aerospace engineer, who is one of the founders of Project Icarus. He is a Fellow of the BIS, Member of the BIS Technical Committee, as well as an active Practitioner of the Tau Zero Foundation.

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