WASHINGTON — The four formation-flying spacecraft comprising NASA’s Magnetospheric Multiscale mission, a $875 million heliophysics flagship, have arrived at Astrotech Space Operations near the Kennedy Space Center in Florida for prelaunch processing, a NASA spokeswoman said Nov. 14.

MMS observatories two and four, the last to ship by truck from the Goddard Space Flight Center in Greenbelt, Maryland, “arrived safe and sound at Astrotech on Nov. 12,” NASA spokeswoman Susan Hendrix wrote in an email.

Observatories two and four arrived after the Oct. 29 delivery of observatories one and two, which also shipped by truck.

Launch of all four MMS spacecraft aboard a United Launch Alliance Atlas 5 is scheduled for March 12. The observatories were built at Goddard.

During its two-year primary mission, MMS, the fourth in NASA’s Solar Terrestrial Probes program, will study how the magnetic fields of Earth and the sun interact. The mission will make the launch date NASA committed to in 2009, albeit at a cost roughly $25 million more than what the agency expected.

NASA blamed the overrun on the two-week partial government shutdown of October 2013, which locked workers out of Goddard while MMS development was in full swing. MMS also had to let the James Webb Space Telescope cut in line for environmental testing at Goddard’s thermal vacuum chamber, forcing the heliophysics observatories to use facilities at the Naval Research Laboratory in Washington.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.