This story was updated at 4:04 p.m. EST.
HOUSTON (AP) - An American astronaut aboard the international space station went back to work Thursday even as he grieved for his mother, who was killed a day earlier when a train struck her vehicle..
Rose Tani, the 90-year-oldmother of astronautDaniel Tani, died Wednesday in the Chicago suburb of Lombard.
Daniel Tani, 46, is believed to be the first American astronaut to lose a close family member while in space, NASA spokeswoman Nicole Cloutier said.
A NASA flight surgeon and Tani's wife informed him of his mother's death Wednesday evening in a video conference call, Cloutier said.
On Thursday, Tani was moving ahead with his normal work on the space station, including working on some science experiments, she said.
Police said Rose Tanistopped behind a school bus at a railroad crossing and then drove around thevehicle, bypassing the lowered crossing gate. The train struck Tani's vehicleon the passenger side and pushed it down the tracks before stopping.
Paramedics took Rose Tanito a hospital, where she was pronounced dead.
"He is obviouslypretty sad," the astronaut's brother, Richard Tani, said in Thursday'sedition of the Chicago Sun-Times. "He was pretty close to her. We are allclose to her. She was loved by everyone."
Daniel Tani was supposed tofly home aboard Atlantis on Wednesday, but the shuttle's flight was postponeduntil January due to a fuelgauge problem. The earliest he could return to Earth at this point is latenext month.
"Before anyonelaunches, they understand that unfortunate things could happen and that'sunfortunately part of the difficulties, hardships and risks of space flight,"NASA spokesman Jim Rostohar said in Thursday's edition of the ChicagoTribune.
NASA spokeswoman EileenHawley told the Houston Chronicle that Tani's duties will be postponedor handled by his crewmates, station commander Peggy Whitson and cosmonaut YuriMalenchenko.
"Something like thisis always very personal, so it will depend on his wishes," Hawley said.
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