For decades now, Europa has beckoned – this moon of Jupiter which is frozen on the outside but hides a global ocean on the inside – has so far only been visited by spacecraft during brief flybys. Scientists and the public alike have been wanting to return to this fascinating little world since it offers the possibility of maybe, just maybe, being home to some kind of life. Plans have been inching forward for a new mission to conduct multiple, closer flybys of Europa, to learn more about the ocean just below the ice, but what about actually landing? A lander would be a more difficult prospect since Europa doesn’t have an atmosphere, but is certainly doable. Now, NASA has received a formal science report on how best to conduct such a mission. This is a significant step toward finally being able have the view of looking up at Jupiter hanging in the inky black Europan sky – a dream of many for a long time.
The subject of water on Mars is one of the most highly debated in planetary science; various missions have provided ample evidence that the planet used to be a lot wetter than it is now, with rivers, lakes and maybe even oceans. Most scientists now generally agree on this, but as to how much water there was, how long it lasted and how warm the environment was, is another question. There have been apparent conflicting lines of evidence, and now findings from the Curiosity rover have only added to the mystery. Curiosity has revealed a paradox of sorts – it has found abundant evidence for ancient lakes in now-dry Gale crater, but at the same time has not found evidence for a previous thicker atmosphere with more carbon dioxide, which normally would be needed for water to remain liquid on the surface. These two lines of evidence seem to contradict each other, so how to resolve this puzzle?
Asteroids are some of the most ancient objects in the Solar System, relics left over from the time when the planets first started forming and evolving. For this reason, scientists are very interested in them, since they can provide clues as to how this process occurred. Most asteroids orbit the Sun in a broad belt between Mars and Jupiter, but they can be found elsewhere in the Solar System as well. NASA’s OSIRIS-REx spacecraft is now en route to one of these asteroids, called Bennu, which it will study and then bring a sample back to Earth. While on the way there, however, OSIRIS-REx will also be searching for other asteroids, called Trojans. These have regular orbits which place them either just before or just behind a planet, including Earth. The spacecraft will be on the lookout for some of these Trojans near Earth this month as it travels toward Bennu.
Long after its incredible encounter with Pluto and its moons in 2015, the New Horizons spacecraft is continuing its journey deeper into the Kuiper Belt in the outer reaches of the Solar System. Mission scientists and engineers are now preparing for its next close flyby, of a smaller body called 2014 MU69, on Jan. 1, 2019. Along the way, New Horizons makes occasional slight course corrections to keep it on track, and now the spacecraft has just successfully completed its latest one.
As the Cassini spacecraft continues its journey through the Ring-Grazing Orbits, it has been sending back some incredible new images of Saturn and its rings, many in detail never seen before. The rings are composed of countless individual streams of particles, all held in place by Saturn’s gravity. Click to view full-size versions of the raw images. All Cassini raw images are available here.
The Juno spacecraft has sent back a beautiful new view of Jupiter’s “Little Red Spot,” a smaller and paler version of the Great Red Spot, which is an anticyclone in the atmosphere (a large-scale circulation of winds around a central region of high atmospheric pressure). Other complex cloud patterns can also be seen. The image was first taken on Dec. 11, 2016. The amazing full image is below:
Thirteen years. That is how long NASA’s Opportunity rover has now been exploring Meridiani Planum on Mars; not bad for a robot which was designed with a hoped-for nominal 90-day mission. Today marks the 13th anniversary of the landing of Opportunity, on Jan. 24, 2004 PST (Jan. 25, 2004 UTC). The mission since then has been nothing short of incredible, as Opportunity soon found evidence that Meridiani Planum used to be a much wetter place than it is now. It was a place where microbial life could have existed; whether it actually did or not is still unknown but Opportunity continues to provide more clues as it continues exploring vast sandy plains and mountainous crater rims.
Twelve years ago today, one of the most incredible space missions ever was accomplished: the first landing of a probe on an alien moon. And this wasn’t just any moon, but Titan, largest moon of Saturn and one of the most fascinating worlds in the Solar System. Although much colder than Earth, Titan mimics some of the processes found here such as its hydrological cycle, but with liquid methane/ethane instead of water. Titan had been observed extensively by telescopes and from Saturnian orbit, but this was the first time the surface could be seen up close.
There have been many incredible planetary missions over the past several decades, from as close as our Moon to the outer reaches of the Solar System. Right now, there are robotic explorers at Mars, Jupiter, Saturn, Ceres, and out past Pluto. But there are two more which have travelled even farther, to the most distant fringes of the Solar System, Voyager 1 and Voyager 2. Although they were launched way back in 1977, they are still active today, studying the region where our planetary system “ends” and interstellar space begins. Now, the Hubble Space Telescope is being used to help provide a “road map” for their future paths forward.
NASA has chosen two new missions to explore the Solar System; it was announced today during a media teleconference. The missions are part of NASA’s Discovery Program, and after the competing proposals had been narrowed down to five contenders, the final two winners were announced. Both missions, called Lucy and Psyche, will visit asteroids which have never been seen up close: multiple Trojan asteroids which share Jupiter’s orbit and the unusual metal asteroid 16 Psyche. These missions will study such objects which are relics left over from the early beginnings of the Solar System, providing new clues as to how the planets and other bodies formed. Two other mission proposals to return to Venus did not make the cut, unfortunately.