The microprobes are also revolutionary in the way they will plunge into Mars. Typical spacecraft use a parachute and rockets, as well as an aeroshell, to slow their descent through an atmosphere and land safely. The Deep Space 2 probes are the first spacecraft to use only an aeroshell. By eliminating parachutes and rockets, the probes are lighter and less expensive, but also very hardy. Similar in weight to a lap-top computer, they are designed to survive a high-speed impact, and to operate successfully in extremely low temperatures, something conventional miniaturized electronics, and standard spacecraft, could never do.