A NASA spacecraft is halfway toward Mars where it is expected to collect more data on the Red Planet than all previous Martian explorations combined. The Mars Reconnaissance Orbiter successfully fired its six engines for 20 seconds last week to adjust its flight path in anticipation of a March arrival. It will fine-tune its trajectory two more times before it enters orbit around Mars, said Allen Halsell, deputy navigation chief at NASA’s Jet Propulsion Laboratory in Pasadena. Once in orbit, the two-ton spacecraft will join a trio of probes currently flying around Mars.