As 2001 rolled in, the Mars Surveyor 2001 was launched. 2003 saw the launch of Europa Orbiter to investigate the existence of water on Jupiter's fourth largest moon. In 2004, the Pluto-Kuiper Express probe was launched. It will take at least eight years to reach the last unexplored planet.

Astronauts of Indian origin have had their part to play too, in this tapestry of human achievement. Kalpana Chawla was one of seven crewmembers lost in the Space Shuttle Columbia disaster that occurred on February 1, 2003, when the shuttle disintegrated over Texas during re-entry into the Earth's atmosphere, shortly before concluding its 28th mission. She was 40 years old.

Sunita Williams (born September 19, 1965 in Ohio) carries forward Chawla's legacy. She currently holds three records for female space travellers: The longest spaceflight (195 days), number of space walks (four), and total time spent on spacewalks (29 hours and 17 minutes). And yes, she also ran the Boston Marathon while on board the space station!

No one knows what our tomorrows will bring. The only thing that's certain is this: For mankind, the sky will never really be the limit.