>>In “ >PM must attend CHOGM, says Swamy ” (Nov. 6, 2013), Mr. Subramanian Swamy was wrongly referred to as Janata Party president. He should have been referred to as a BJP leader or former Union Minister.
>>An entry in the graphic titled “A voyage to Mars” that was inset into the report, “ >‘Meaningful scientific experiments’ to be conducted on the Red Planet ” (Nov. 5, 2013) said: “After a journey ... covering 680 million kilometres, the spacecraft will reach its destination.” A reader wrote to say that this was at variance with the opening sentence of “Mars mission is a month away” (Sept. 12, 2013, Science & Technology page) which read: “India’s very own Mars excursion -- a journey of over 385 million km -- is just over a month away.”
The Science Correspondent’s clarification: The distance between Earth and Mars varies depending on where the two planets are in their respective orbits around the Sun. At their farthest, the two planets are separated by a distance of about 400 million kilometres. At the time when Indian orbiter leaves Earth orbit and heads for Mars, the distance between the two planets will be about 250 million kilometres. However, the spacecraft will be taking a long, curving trajectory that minimises propellant consumption. In that trajectory, the probe will take nearly 300 days to traverse 680 million kilometres and reach Mars.
