"The way we're going to land humans on Mars is with propulsion systems and landing legs," said Ed Weiler, associate administrator for NASA's Science Mission Directorate.
Mars is about 171 million miles (275 million kilometers) away, so data transmissions can take more than 15 minutes to reach Earth.
The craft is able to send UHF radio signals directly to Earth-based telescopes, but most of its engineering data and images are being sent via relays through Mars-orbiting probes.
A few minutes after landing, the orbiters moved out of range of Phoenix, so scientists had to wait for about an hour and a half to re-establish contact and start collecting information.
The first data stream includes images of both 18-foot-wide (5.5-meter-wide) solar arrays fully deployed, as well as a footpad firmly planted on the surface.
Over the next few days scientists will study the probe's surroundings and conduct a full health check on the lander and its payload of scientific instruments.
Once Phoenix gets its bearings, it can begin its 90-day mission to dig deep into the Martian permafrost and analyze soil and ice samples, in part to determine whether Mars ever had the right conditions to support life.