Anissia Narang was at the gym when the television attached to her treadmill announced that the space shuttle Columbia had lost contact with the ground.

A close friend of hers, Kalpana Chawla, was among the crew.

"She had invited me to the launch," says Narang. She had also told me that since it keeps getting postponed, I might have to stay in Florida for a few days.

Narang, who runs a small business in Birmingham, Alabama, took a rain check. "I told her I would visit her in Houston in summer."

When it was confirmed, on Saturday afternoon, that there were no survivors from Columbia, it dawned on Narang that she would never see Montu -- as Chawla's family and friends affectionately called Kalpana -- again.

The two became friends at the Punjab Engineering College where Chawla studied aeronautics and Narang enrolled in electronics. They were the only women in their respective branches.

Narang was inspired by the tomboyish girl with short hair, who was always clad in a shirt and trousers, loved building airplane models and was an avid reader.

"She liked autobiographies," says Narang. "Recently, when it took me two months to finish reading the autobiography of Katherine Graham, she laughed and said it was two weeks' job."

The two chatted over the phone at least once every month.

Kalpana would love anything new and adventurous, says Narang.

Back in college in 1980, Chawla arranged karate classes for the girls' hostel. Almost everyone enrolled, Narang says.

"It was she who taught me how to ride a bike."

Later, in the US, having learnt ice-skating, skiing, swimming and kayaking, Chawla motivated Narang to do the same.

"She was not an ordinary girl, but she was very down-to-earth, totally focused on her work," she says.

"She believed that you have to do your own thing."