In a letter sent to SpaceX founder Elon Musk, PETA has urged the sending of only vegan flights during any future SpaceX missions to Mars.

The letter has been sent by PETA president Ingrid Newkirk and promotes the establishment of an all-vegan Martian colony.

The suggestion comes amid speculations of possible human colonization of the Red planet. Earlier, Elon Musk has expressed his wishes of sending men on Mars within next 10 to 20 years. The company is also developing a capsule called Dragon and a heavy-lift rocked called Falcon Heavy for the purpose.

So far, Dragon and Falcon 9 flew one successful test flight to orbit in December 2010. Moreover, scientists at NASA have also recently announced the detection of flowing saltwater on the planet which might help to sustain life.

Newkirk mentioned in his letter that given the present conditions and scientific advancements, Musk's proposed colony may lie in the not-too-distant future.

If Elon Musk's vision of a colony on Mars comes true, the last thing those people will need is the disease and destruction that results from eating animals, Newkirk stated.

In response to this, Musk told Space.com that he is a big fan for free choice for any future Martian colony.

It is likely that early Mars colonists would have a mostly vegetable diet, because of the energy and space needed to raise farm animals, he informed.