Kuiper belt versus Oort cloud

Friday May 26, 2023 11:47 am

Beyond the orbit of Neptune lies the Kuiper belt. This thick disk of icy rocks is more or less aligned with orbit of planets in the solar system. It is similar to asteroid belt spanning between orbits of Mars and Jupiter, but considerably larger. It is believed that Neptune and Saturn have got some moons from Kuiper belt. Around 100000 icy and rocky objects including Pluto and some other dwarf planets are contained in Kuiper belt. First spacecraft to explore Kuiper belt was New Horizon.
Oort cloud – lies beyond Kuiper belt and is gigantic sphere of icy rocks. It is believed that Oort cloud surrounds whole of solar system and is 2 light years away from earth. Edge of the Oort cloud is regarded as edge of our solar system. Not much is known about Oort cloud except the fact that majority of comets in our solar system come from it. Objects in the Oort cloud are very dark and difficult to observe as Oort cloud is very far from the sun. No spacecraft has till now reached Oort cloud and Voyager 1 & 2 will take 300 years to reach inner edge of Oort cloud. 30000 years will be needed by Voyager missions to go past Oort cloud.

The distance of the Oort cloud from us can be visualized by comparing the distance range of Pluto from the sun with the assumed distance range of the Oort cloud from the sun. The orbit of Pluto is elliptical and takes it 30 to 50 AU away from the sun. In comparison inner edge of the Oort cloud is believed to be between 2000 and 5000 AU away while the outer edge is between 10000 and 100000 AU away from the sun. The inner edge of the Kuiper belt is just 30 AU away from the sun. A ray of sunlight takes 8 minutes to reach the earth, 4.5 hours to reach Neptune’s orbit, and 7.5 hours to reach the outer edge of the Kuiper belt, and will need 10 to 28 days to reach the inner edge of the Oort cloud.
Kuiper belt icy objects are remnants from the process of formation of the solar system and in that way quite similar to objects residing in the Oort cloud. These objects present in the Kuiper belt and Oort cloud are called planetesimals.

It is believed that icy planetesimals present in the Oort Cloud were not this far away from the sun initially, the gravity of planets shoved some planetesimals into the Oort Cloud while some were banished from the solar system forever.

History of Space Exploration

Thursday May 4, 2023 10:35 am

Space Exploration by mankind is but natural. The infiniteness of outer space has been visible to human eyes even before the outset of human civilization. Man has been gazing at the sky with astonishment since time immemorial and when this gaze became exploration is difficult to know.

The first man explored outer space with naked eyes, later on using the telescope, and in the twentieth century, the man started exploring outer space physically. Physical exploration started with unmanned spacecraft leaving Earth’s atmosphere for outer space but manned missions followed. Technological advancements combined with the perseverance and willpower of mankind made this possible.

Motivation for physical exploration of space

1.  Greed is the biggest motivator for any exploration. Exploiting natural resources has become human nature. Mankind wants to explore outer space to exploit natural resources maybe. Natural resources present on earth are depleted due to unnatural exploitation by mankind. After Europeans discovered the Americas they started the unnatural exploitation of abundant natural resources there and depleted natural resources there too. Now Mankind’s urge for unnatural exploitation of natural resources is taking it to outer space.  Man believes that natural resources in outer space are endless.
2.  Curiosity about extraterrestrial life is another big motivator. Many spacecraft have been sent to outer space in search of extraterrestrial life. It is difficult to believe that we are all alone in this vast universe. Initially, the human mind was fixated on the urge to find multicellular organisms like us or like plants and animals on earth but now attempt is to find any type of life, even microbial. Till now attempts to find any extraterrestrial life have not succeeded.   
3.  Finding alien land for human habitation is another motivation. Europeans discovered the Americas and inhabited it. Likewise, they want to imperialize alien land in outer space. Advancements in science and technology can make this possible. Many space programs have been designed to find Earth-like planets.

Benefits of space exploration

1.  Health care improvement – Space travel of humans can help understand the human body better. The technology behind space robots was used to develop surgical robots and robots with the capability of performing biopsies and detecting breast cancer.
2.  Everyday life has been impacted hugely by the physical exploration of space. GPS technology, accurate weather forecasts, telecom, assistance in agriculture, etc. are some eventualities of space exploration.
3.  Space exploration has ended up creating an atmosphere for the launch of satellites that help protect the environment of our planet.
4.  Space exploration also gave a fillip to space technology that can enhance safety on Earth by warning about impending natural disasters, assisting rescue operations, etc.
5.  Preparing the world for misuse of space technology in wars is another benefit. It is believed that space technology can play a vital role in wars of the future and it is important to take remedies. Space wars are a distant possibility but if all that happens then space technology will help. All space technology has developed thanks to the space exploration urge of mankind.

Unmanned spacecraft

It all started with the launch of Sputnik 1 which was an unmanned Soviet spacecraft. Sputnik 2 was another unmanned spacecraft with a dog onboard. Even after the launch of the first manned spacecraft, unmanned spacecraft have been launched with regularity. All satellites have been launched using unmanned spacecraft.

Manned spacecraft

Vostok 1 was the first manned spacecraft launched with Russian astronaut Yuri Gagarin onboard. Many other manned spacecraft were launched including Apollo 11 which took Neil Armstrong to the moon. Today international space station is manned by astronauts from different nations.

Space Programs

Wednesday May 3, 2023 6:30 am

When it all started, the stated aim of space programs was an exploration of outer space. But as time passed real intentions came to the fore. Today the USA has two separate space programs. The civilian space program is run by NASA while the military space program is run by the United States space force and United States space command. The United States is not the only country that has space programs. Many developing countries apart from developed countries have space programs. The military space program is also not unique to the USA. Countries are running space programs in collaboration with other countries. The international space station is a prime example of international cooperation in running space programs. One country launching a satellite of another country is usual stuff now.

Generally, space agencies are run by governments but numerous private companies also boast of space programs. Numerous countries have their own space agencies but the difference is in degree of competence. The European space agency is unique in the sense that it is one of the most advanced space agencies not run by any one country but by multiple European countries jointly as an intergovernmental organization. Launch capability is the competency without which running a space program of significance is not feasible. Today government space agencies of not one or two but about 20 countries apart from ESA have launch capability. Space agencies of five countries and the ESA has extraterrestrial exploration capability. Human spaceflight capability is still not possessed by space agencies of too many countries. NASA is leading the bunch of space agencies with CNSA as a distant second, as far as budget is concerned.

Timeline of space missions

Few would be aware that the first rocket to reach outer space WAC Corporal was launched in 1946 by the USA. In 1957 first ICBM was developed by the Soviet Union and the Soviet Union sent the first artificial satellite Sputnik 1 in 1957. Vostok 1 and Vostok 6 took the first man and the first woman in space respectively in 1961 and 1963 respectively.

Apollo 11 took the first human to the moon. Many space missions are in the pipeline even now. Private players have also jumped in.

Space missions of developing world   

The developing world is not lagging behind in sending space missions. The Indian space program has got due recognition. It all started with humble Aryabhatta in 1975 but today manned mission is being planned. India has already launched a Mars orbiter mission.

Indian space agency ISRO has launch capability and has launched satellites from many countries apart from India.    

Space Tourism

Tuesday May 2, 2023 10:56 am

There is ample evidence of the fact that prehistoric man was not at all accustomed to sedentary life. That means man is a wanderer by nature. As man became civilized sedentary life got wide acceptance but still, man remained a wanderer by nature. History is replete with evidence of this fact. Europeans imperialized Africa and Asia because of this nature, the discovery of the Americas was caused by this nature, and the voyage to the moon was also because of this nature. Today tourism is a big industry just because man is a wanderer by nature. So, space tourism was destined to start sooner or later.

When it all started? 

Space tourism started way back in 2001. Tourism is nothing but traveling purely for recreational purposes. Dennis Tito went to ISS (International space station) in 2001 aboard the Russian spacecraft Soyuz solely for recreational purposes and became the first space tourist. Tito shelled out $20 million for the trip. Between 2001 and 2009 8 tourists went into orbit utilizing government rockets. It was in 2021 that all-private missions reached orbit. Elon Musk-owned SpaceX made this possible. Quite naturally SpaceX is the space tourism industry leader. No private player can match SpaceX in orbital space tourism. ‘Virgin Galactic’ and Amazon founder Jeff Bezos funded ‘Blue Origin’ are competing for dominance in the suborbital space tourism business.

The distinction between suborbital and orbital space tourism

The basic difference between suborbital space flights and orbital space flights is the speed at which the spacecraft moves. A spacecraft can go into orbit only if it attains orbital velocity (28000 km/hour). A spacecraft that moves at a speed below orbital velocity can never go into orbit and its flight will be called suborbital space flight.

Tourists who go to space on suborbital spacecraft are called suborbital space tourists. They venture into space but never orbit the Earth. If a spacecraft attains orbital velocity it will go into orbit and tourists onboard will become orbital space tourists. SpaceX is the only private company that offers orbital space tourism services. Russian spacecraft Soyuz was the initial provider of orbital space tourism facilities. Suborbital space tourism facility is being provided by Virgin Galactic and Blue Origin, which are both privately owned. Today dominance of government agencies in the space tourism business has ended. The point to be noted here is that suborbital space flights are rightly called space flights because spacecraft undertaking such flights reach the Karman line before returning to Earth. The Karman line is 100 km above sea level and is a demarcation line between Earth’s atmosphere and outer space. So, although said spacecraft may never go into orbit but always venture into space. Suborbital flights failing to reach the Karman line don’t qualify as spaceflights.