(CNN) -- NASA astronaut Peggy Whitson, along with two cosmonauts, rode in the Russian Soyuz spacecraft that made a gut-wrenching, off-target landing last month.
She said the Soyuz spacecraft hit the ground so hard it bounced -- although she didn't know it at the time.
"From inside the capsule I had no perspective that we actually had bounced, it was just one big hit and a roll," Whitson said Friday in a telephone interview from the Johnson Space Center in Houston, Texas.
The troubled April 19 landing returned Whitson to Earth after a six-month stint as commander aboard the International Space Station.
No astronaut has spent more time in space than Whitson -- 377 days in two space station missions.
Unlike the space shuttle, equipped with wheels for runway landings, Soyuz craft descend to Earth on parachutes and then use three small engines to slow the craft to a comfortable touchdown.
Russian engineers are still trying to find the problem that sent the Soyuz craft into a steeper-than-normal descent, so that it came down about 260 miles from its intended landing site in Kazakhstan.
A Russian commission has been set up to investigate the rough landing -- the second straight re-entry malfunction for the recently modified Russian-made spacecraft. NASA is monitoring the progress of the investigation.
Whitson told CNN Radio that Russian engineers are "motivated to figure out what happened" especially "to keep it from happening (again)."
In 2010, the space shuttle fleet is scheduled to be retired, leaving only Soyuz spacecraft available for ferrying crew members to the International Space Station. E-mail to a friend