Unlike similar instruments aboard Mars orbiters, which study the planet from space, RIMFAX will be the first ground-penetrating radar set on the surface of Mars.
As Ferguson withdrew for "personal reason", veteran NASA astronaut Barry "Butch" Wilmore will join astronauts Mike Fincke and Nicole Mann for the Boeing crew flight test, the US space agency said on Wednesday.
The US space agency recently pushed back the target for the launch of its next great space observatory, the James Webb Space Telescope, from March 2021 to October 2021.
At 5.32 a.m. EDT (3 p.m. India time), Expedition 63 Commander Chris Cassidy of NASA used the robotic Canadarm2 to grapple the Northrop Grumman Cygnus spacecraft as Ivan Vagner of Roscosmos monitored Cygnus systems during its approach.