Mars may be the first planet in the solar system to have a robot for mayor. (Something that was already predicted by Reddit.) NASA's Curiosity rover just checked-in on Foursquare on Mars and, unless Opportunity gets its act in gear, could continue to check-in unopposed and win the coveted spot of mayor.
Venus is sometimes called the Earth's twin because of its similar size and orbital distance from the Sun, but it's more like a backwards, inside-out Earth. Venus rotates on its axis in the opposite direction from the solar system's other planets, and it's hot — surface temperatures average around 890°F. But it looks like Venus isn't hot all over.
Titan is pretty Earth-like. It's got methane cycles akin to our planet's water cycle, and it's inclined by about 27 degrees, similar to the Earth. That incline means Titan has season like Earth does, and scientists have collected 30 years of data about the moon's seasons, the equivalent of a full year. Turns out, Titan's seasons are another similarity the moon has with our own planet.
Even rightly so, too often the Apollo program dominates the narrative of early lunar exploration. The Soviet Union ran its own lunar program in the 1960s and '70s, and it was so successful early on that it looked like the Moon would be Soviet territory. The first ever man-made object to land on its surface in 1959 was the Soviet-launched Luna 2. The first image of the lunar far side came during a flyby by Luna 3 the same year. In 1966, Luna 9 transmitted the first pictures from the surface of the Moon, and Luna 10 would enter into its orbit. In 1968, a handful of turtles and other simple organisms even made the first circumlunar voyage aboard Zond 5. But Apollo 8 swept the rug out from the Soviet's feet; three astronauts going into orbit in December of that year all but assured the world that the political victory of landing on the Moon would go to the Americans. So the Soviets reshaped their lunar program, choosing to focus on inexpensive robotic mission that put science goals at the core.
Like everything they build, engineers at NASA's Jet Propulsion Laboratory (JPL) designed Curiosity's Sky Crane landing system to work. But nothing is guaranteed in spaceflight. The team wouldn't know for sure whether the mission's entry, descent, and landing (or EDL) was successful until they got confirmation from the rover. The problem was that Curiosity's landing site in Gale Crater would be out of range at touchdown, so the team brought in a communications relay: the Mars Odyssey orbiter. It was a simple and obvious solution, except that Odyssey experienced its first ever malfunctions weeks before Curiosity's landing.
It's not often you get to sit and watch history being made, but that's what happened tonight. Curiosity landed on the surface of Mars, inside Gale Crater, with the most complicated and sophisticated landing system ever sent to the red planet. The mission's complexity has been likened to Apollo 11's landing on the Moon in 1969.
Before Wernher von Braun designed the mammoth Saturn V rocket that sent Apollo astronauts to the Moon, the German rocket scientist nursed a dream to see men travel to Mars. In the 1940s, he started studying different Mars missions that were ahead of their time but feasible with the technology and techniques he had at his disposal at the time.