NASA astronauts Joe Acaba and Mark Vande Hei Acaba visited Marshall April 11 for their honorary Expedition 54 plaque hanging ceremony and to provide valuable feedback of their on-orbit science investigations with the Payload Operations and Integration Center team. Chris Buckley is awarded privilege of hanging Mission 54 placque, shown here with Astronaut Mark Vande Hei (L) and Astronaut Joe Acaba

NASA astronauts Joe Acaba and Mark Vande Hei Acaba visited Marshall April 11 for their honorary Expedition 54 plaque hanging ceremony and to provide valuable feedback of their on-orbit science investigations with the Payload Operations and Integration Center team. Astronauts Mark Vande Hei (L) and Astronaut Joe Acaba sign autographs for Kassandra Stephens

NASA astronauts Joe Acaba and Mark Vande Hei Acaba visited Marshall April 11 for their honorary Expedition 54 plaque hanging ceremony and to provide valuable feedback of their on-orbit science investigations with the Payload Operations and Integration Center team. Astronauts Mark Vande Hei (L) and Astronaut Joe Acaba sign autographs for Samantha Gurley.

NASA astronauts Joe Acaba and Mark Vande Hei Acaba visited Marshall April 11 for their honorary Expedition 54 plaque hanging ceremony and to provide valuable feedback of their on-orbit science investigations with the Payload Operations and Integration Center team. Payload Operations Director Phillipia Simmons with Astronauts Joe Acaba (L) and Mark Vande Hei

NASA astronauts Joe Acaba and Mark Vande Hei Acaba visited Marshall April 11 for their honorary Expedition 54 plaque hanging ceremony and to provide valuable feedback of their on-orbit science investigations with the Payload Operations and Integration Center team. Astronauts Mark Vande Hei (L) and Astronaut Joe Acaba sign autographs for Lori Meggs.

Stephanie Shelton, a payload communications manager at NASA's Marshall Space Flight Center, joins NASA astronauts Joe Acaba and Mark Vande Hei for a call to the onboard crew of the International Space Station. Vande Hei and Acaba visited Marshall April 11 for their honorary Expedition 54 plaque hanging ceremony and to provide valuable feedback of their on-orbit science investigations with the Payload Operations and Integration Center team..