It's the fourth anniversary of ISRO's Mangalyaan today, and with each passing year, human dreams of colonizing Mars are inching closer and closer to reality.
We take a brief look at them.
SpaceX's plan to get humans to Mars
Elon Musk's SpaceX plans to get to Mars much before NASA, with the latter planning to get to the Red Planet by the 2030s.
Musk, however, plans to send humans to Mars by 2022, and has proposed using a mega rocket codenamed the "Big F**king Rocket" to achieve the same. The BFR is still in the design phase.
The estimated cost is $10bn.
NASA takes the more cautious route
NASA will take a slightly longer route than SpaceX through what it calls the "Deep Space Gateway".
Starting with expeditions in the vicinity of the Moon in the 2020s, NASA plans to test the waters before sending humans to Mars.
Humans will reach Mars aboard the Orion spacecraft that will be "carried aloft by the tremendous power of a Space Launch System rocket".
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Split opinions about Musk's ambitious scale
While Musk's vision puts the carrying capacity of SpaceX ships to be about 100 passengers, experts remain skeptical about the viability of the same.
On one hand, NASA's former chief technologist Bobby Braun said that he remains confident about Musk's plan despite it being highly ambitious.
On the other hand, Mars Society founder Robert Zubrin thinks Musk should start small, and then scale up.
NASA is putting extensive focus on the question of sustainability
Mars is devoid of several factors required to sustain life, and NASA is developing systems to make it more hospitable.
It's working on creating Oxygen Generation Systems like the one aboard the ISS. NASA is also working on making a system to recycle water from every source, along with exploring ways of growing food on Mars.
SpaceX, however, remains silent on sustainability.