Sunita, 41, the daughter Deepak and Bonnie Pandya, arrived at the Kennedy Space Center in Florida for a final stretch of training and preparations for Friday's shuttle mission STS-116, the first night launch since the 2003 Columbia disaster.
The spaceflight is scheduled to lift off at 8.05 IST on Friday (Thursday, 9:35 pm EST) will take along the most rookie crew since 1988 as five of the seven members have never flown in space before.
Besides Sunita, the crew includes mission commander Mark Polansky, pilot William Oefelein, mission specialists Joan Higginbotham; Nicholas Patrick; lead spacewalker Bob Curbeam; and the European Space Agency's Christer Fuglesang, who will become the first Swede in space.
Second Indian woman for NASA space mission
Describing as having most culturally diverse space shuttle crew, Sunita said she was aware of her mixed ethnicity and the interest her spaceflight has aroused in India. "I am half Indian and I have got a, I am sure, a group of Indian people who are looking forward to seeing this second person of Indian origin, flying up in space," she said in a pre-flight interview released by NASA.
Tomorrow: Exclusive rediff.com interview with Sunita Williams!
NASA says the Discovery shuttle will be on the most complex mission yet -- to give the International Space Station a new electricity system. The STS-116 will drop off Sunita for a six-month stay at the space lab.
German astronaut Thomas Reiter of the European Space Agency, will return to earth in place of Sunita.
"I just can't wait to get to my new home," she said. "I have always wanted to fly a long-duration mission," Sunita said.
"A long-duration spaceflight will supply answers... to what happens to the human body, how materials work in space."
Unlike Chawla, who was born in Karnal in Haryana, Sunita was born and brought up in the US. Born in Ohio to Deepak N Pandya, a physician who migrated to the US and Ursaline B Pandya, she grew up and went to school in Massachusetts. She has a BS, Physical Science degree from the US Naval Academy, and an MS in Engineering Management from Florida Institute of Technology.
In two spacewalks the astronauts will rewire the orbiting station, replacing its eight-year-old temporary power cable system with a permanent one, made possible after the previous mission in September installed two huge electricity- generating solar array panels on the ISS.
Sunita is expected to take a spacewalk with her Discovery colleague Robert Curbeam to help rewire the ISS space lab and also operate the space station's robotic arm, among other tasks.
Kalpana Chawla: Inspiration for an entire generation
Trained to remain aboard the space station until July, Williams will also join space station commander Mike Lopez-Alegria for three spacewalks early next year. "My eyes are set on getting out the door, doing my first spacewalk and getting acclimated to living in space.
"I'm just really happy to be here. It's been a long time coming," Sunita said, adding that she's spoken with her Expedition 14 crewmate-to-be Mikhail "Misha" Tyurin. "Misha Tyurin called the other day and said 'Suni, we're waiting for you! So I just can't wait to get to my new home."
Sunita was selected for the astronaut programme by NASA in June 1998, in part because of her extensive experience on more than 30 different aircraft. When not at her work, Sunita likes to swim, bike, windsurf and indulge in bow hunting. And there is philosophical side to her also, she says, "when I eventually step out into space, I am sure I shall spend time looking at our earth. With just the helmet visor between it and me, I am sure I would see just how magnificent it is and yet how fragile".
Discovery will also transport a new 11-million-dollar truss segment weighing two tonnes for the ISS that will be installed during a spacewalk. The Discovery launch will be the first night launch in four years.
'Kalpana belonged to the universe'
NASA has required daylight liftoffs ever since the 2003 Columbia accident, in which Kalpana Chawla was killed, to make sure the agency could get good daytime photos of the external fuel tank in case debris fell from it during launch. Foam breaking off the tank and striking Columbia's wing at liftoff caused the damage which led to the disaster that killed seven astronauts.
Comforted by the acceptable levels of foam loss during the last two liftoffs, NASA officials now believe radar is sufficient to spot pieces falling from Discovery's tank, and that the illumination from the solid rocket boosters will provide enough light to take images during the first two minutes of liftoff. Plus there are inspections in orbit to spot any unseen damage.
Building the station is years behind schedule after long safety-related delays, and space agency is in a race to complete the ISS before its aging shuttle fleet is retired in 2010.