The purpose of the program was to do high-risk technology demonstration, with a motto "Taking risks to reduce future danger.

The penetrator concept is potentially a lower-cost approach, and has a proposed advantage of giving access to the subsurface of the planet being studied (in this case, Mars.)

These goals were “1) to derive the atmospheric density, pressure, and temperature throughout the entire atmospheric column, 2) to characterize the hardness of the soil and possibly the presence of layers at a scale of tens of centimeters, 3) to determine if ice is present in the subsurface soil, and, 4) to estimate the thermal conductivity of the soil at depth.”[6] The eventual goal for such probes was to deploy networks “around a planet using no more resources than a single landing under conventional assumptions.”[7] The probes were launched with the Mars Polar Lander on January 3, 1999, on a Delta II 7425 Launch Vehicle.

Upon arrival near the south polar region of Mars on December 3, 1999,[1] the basketball-sized shells were released from the main spacecraft, plummeting through the atmosphere and hitting the planet's surface at over 179 m/s (590 ft/s).

Its readings could “be used to derive a density profile of the Martian atmosphere” based on the acceleration data combined with knowledge of the probe's speed and ballistic coefficient.

[9] • Evolved Water Experiment: A small sample collection system in the forebody would bring Martian regolith into a heating chamber.

[6] Custom electronics and batteries were designed for the Deep Space 2 probes to survive extremely high accelerations on impact with the surface of Mars and the cold temperatures that it would experience once in operation.

[13][14] Despite the failures of Mars Polar Lander and the two Deep Space 2 probes, Planum Australe, which served as their exploration target,[15] would in later years be explored by European Space Agency's MARSIS radar, which examined and analyzed the site from Mars' orbit and even determined that the area had water beneath its vast area of ice.

[16][17][18][19] Images which were obtained from MARSIS also determined that the water discovered beneath Planum Australe was in fact saltwater.