Dmitri Starosyeltsev had to overcome some tough competition to win a position on the nuclear submarine Kursk after he was drafted in November.
Two of every three candidates were rejected. But Starosyeltsev, who graduated with good marks from the Railway College in the city of Kursk, won out.
One of the novices in the 116-member crew, he was aboard the submarine when it sank in the Barents Sea last weekend.
Starosyeltsev's mother, Valentina, said she was proud when he was chosen to serve on the submarine. Before he left for military service, the professional nurse told her son that if anything ever went wrong, he should not lose heart but should pray.
"And that's what I think. He should not lose heart now," she said in a telephone interview from her home in Kursk after a rescue attempt had failed.
The city of Kursk, nearly 300 miles south of Moscow, was the site of one of history's greatest tank battles, where Soviet forces defeated German armoured units in July 1943.
Because the submarine is named after the city, the young men of Kursk strive to serve on board. Starosyeltsev turned down a position in the elite Kremlin guard in favour of training on the submarine.
On Monday, she was about to go to the post office to send her son a parcel with sweets, razor blades, note paper and socks when she turned on the mid-day television news and saw one of the first reports about the disaster.
"I heard the submarine was lying on the seabed. I didn't understand what it meant because I'm not a specialist, but I understood that something had gone wrong," she said.
She said her son had been eager to board the submarine for his second mission, which began on July 23rd. He served a two-week stint earlier.
Valentina Starosyeltsev expressed anger that the Russian navy had offered little information or support to her family. She said the family was anxiously watching updates on television, desperate for news of her son.
She read aloud excerpts from his most recent letter, written late last month.
"Thank God, I'm finally here," he wrote in a message full of pride and excitement, explaining how lucky he felt to be part of the crew. Everyone, including officers, called one another by their first names, and the officers were almost like fathers.
"I'm really happy," he wrote. "We have four meals a day here, just like home. We will resurface in the middle of August. See you soon."