From the launch of the first satellite in space and that historic first step on the moon; building the $100 bn space laboratory to the latest Parker Solar Probe destined for Sun… mankind’s quest to explore the cosmos has led to several pathbreaking initiatives...

Sputnik 1: Launch of first satellite in space

Sputnik 1, the first man-made satellite, was launched on October 4, 1957, by the erstwhile USSR. It was little more than the size of a basketball and weighed 83.6 kg. This primitive satellite was not equipped with much scientific instruments. However, Sputnik ushered in the new age of space exploration and initiated the US/ USSR “Space Race” that would lead to various manned and unmanned missions to outer space. Sputnik 1 orbited Earth for three months before burning up while falling from orbit into the Earth’s atmosphere on January 4, 1958. Several replicas of the Sputnik 1 satellite can be seen at museums in Russia. The Sputnik 1 launch also led directly to the creation of the American space agency, National Aeronautics and Space Administration (NASA) in 1958.

Apollo 11: First manned mission to the moon

The historic Apollo 11 mission launched from Cape Kennedy on July 16, 1969 carried three astronauts towards the moon— Neil Armstrong, Michael Collins and Edwin “Buzz” Aldrin.  Apollo 11 travels 240,000 miles in 76 hours to enter the lunar orbit on July 19. A day later, Neil Armstrong sets foot on the moon, Buzz Aldrin followed him. NASA’s websites say that “An estimated 530 million people watched Armstrong’s televised image and heard his voice describe the event as he took “...one small step for a man, one giant leap for mankind” on July 20, 1969.  They collected samples from Moon’s surface, took photographs and erected an American flag on the lunar surface before they returned back to spacecraft.  The enterprise that put men on the moon also gave impetus to technologies that we use today.

International Space Station: Habitable artificial satellite

Imagine how excruciatingly painful and challenging it would be to build a laboratory in space that would be as big as an American football field upon its completion, while also providing a liveable environment in which astronauts could continuously work. International Space Station (ISS) was taken into space piece-by-piece and gradually built in orbit. Its first component was launched into orbit in 1998. But it wasn’t until November 2000 that the first batch of humanity’s representatives blasted off on a Soyuz spacecraft to live aboard the artificial satellite. The ISS has been continuously occupied ever since. It was assembled during 160 spacewalks with parts delivered by more than 100 space flights. ISS has proved critical in developing technologies that will go a long way in making interstellar travel safer.

Apollo 13: Space rescue

NASA’s third space programme en route to the Moon —Apollo 13 — was launched on April 11, 1970.  But the lunar landing was aborted after an oxygen tank exploded two days later, threatening the lives of three astronauts. The crew was 200,000 miles from Earth and landing on the moon was impossible, even returning safely to Earth would be a miracle. The only bright spot was that the Apollo 13 lunar module remained unharmed in the explosion. The astronauts and NASA engineers searched for ways to utilise the supplies and equipment of the lunar module. The astronauts also showed tremendous courage, surviving temperatures near freezing, and dehydration for four days. The module successfully entered Earth’s atmosphere before splashing into the Pacific Ocean.

Voyager I: Farthest man-made object from Earth

When Voyager 1 blasted off from Earth on September 5, 1977, it was designed to last for five years. Today, after more than 38 years, the space probe continues to communicate with NASA.  It left the solar system in August 2012, thereby becoming the farthest spacecraft from Earth and the only one in interstellar space. It currently takes approximately 16 hours and 38 minutes to receive communication from Voyager 1. The probe’s primary mission objectives included flybys of Jupiter, Saturn, and Saturn’s large moon, Titan. Its onboard nuclear power generator gives it around 10 more years of life before it disappears in deep space for forever.  In order to provide a sense of Earth’s culture to any spacefarers encountered by Voyager 1, NASA included a 12-inch gold-plated audiovisual disc on the craft. It includes photos and drawings, spoken greetings, music and Earth sounds.

Water found on Mars: Indication of life?

Potentially life-giving water still flows across the ancient surface of Mars from time to time, discovered NASA scientists on September 2015. Scientists are unsure where the water comes from, but it could rise from underground ice or salty aquifers, or condense out of the thin Martian atmosphere. The findings, that came from NASA’s Mars Reconnaissance Orbiter (MRO), raise the possibility there could be life — or even microbes — inside the Red Planet. MRO has been examining Mars since 2006. The Red Planet is now the only one in our solar system to show signs of water on its surface, other than our own.  But to make Mars habitable on larger scale we need to terraform it by melting the planet's icy poles. Some of the possible ways proposed are: nuclear detonation, smashing asteroids on its surface, releasing human-engineered microbes, setting greenhouse gas factories among others.

Hubble Space telescope: Becomes operational

Since the time of Galileo, astronomers have shared a single goal — to see more, see farther, see deeper. Hubble Space Telescope which was launched on April 24, 1990, has done exactly that. The work began in 1975, but it took 15 years to launch Hubble. It has 10 times the resolution of a ground-based telescope and 50 times greater sensitivity to light. The famous telescope has beamed hundreds of thousands of images back to Earth, shedding light on many mysteries of the universe. It has discovered numerous galaxies, stars and distant planets, helped us in determining the age of our universe and confirned the existence of dark energy. More than 10,000 scientific articles have been published, based on Hubble data.  John Grunsfeld, a former astronaut who serviced Hubble on three different space missions, in an address said, “Hubble still has a tremendous journey ahead of it. I'm still convinced that its greatest discovery lies ahead.”

Which among these is the most iconic moment according to you? And why? Let's know in the comments section below.