Our own Chief Astronomer, Derrick Pitts, has ranked his five most important space stories for 2015. See if your favorite event made the list!
1. Water on Mars!
IMAGE: Dark, Recurring Streaks on Walls of Garni Crater on Mars | 2015 | NASA/JPL-Caltech/University of Arizona
Thanks to the work of three different roving laboratories on Mars, we’re now certain that our rusted neighbor planet was awash with oceans of water billions of years ago. Is there any water still there? Recent photos of darkened slope soils taken by Mars-orbiting satellites indicate the strong possibility of liquid water near the surface. The appearance and disappearance of the darkened soils suggest that given the right conditions subsurface ice melts and the water trickles down the slopes leaving the darkened soils. Because Mars’ atmosphere is almost non-existent, the trickling water evaporates away almost immediately but not before soaking the soil to create the darkened trails. These photos, along with radar scans that detect subsurface ice and other surface evidence, proves that Mars at one time in its distant past was just as much of a water planet as is Earth!
2. New Horizons reveals a new planet
After nearly ten years of travel, the New Horizons spacecraft finally reached the King of the Dwarf Planets, Pluto. In less than an hour of close flyby, New Horizons gathered enough data and images to completely change our understanding of the nature of Pluto. Not just a small cold ice world, Pluto revealed a surface of wildly different textures and features, hills and plains, with a variety of colors and defined areas, all completely unexpected. It even shows a vast surface region that looks relatively recently formed, but we have yet to figure out just what mechanism would’ve formed it. New Horizons will send us more information about Pluto but now continues its journey into the outer reaches of the solar system where astronomers suspect other Pluto-like objects hang out.
3. Two Astronauts Spend a Year in Space
IMAGE: Scott Kelly Becomes U.S. Astronaut to Spend the Most Time in Space | 2015 | NASA
American astronaut Scott Kelly and Russian astronaut Mikhail Kornienko are part of a special NASA experiment to test the effects of the space environment on the human body. Kelly and Kornienko together will be the first humans to spend one continuous year in space aboard International Space Station. What makes the experiment particularly effective is that Kelly’s twin brother Mark Kelly is also a NASA astronaut and will act as the ‘control’ component of the experiment here on Earth. In other words, since Scott and Mark are twins, NASA medical researchers will be able to more easily track differences between the two identical bodies having had Scott in space and Mark here on Earth. The differences in the effects of long-term spaceflight between Scott Kelly and Kornienko will help sort out non-space related changes that might be specific to the Kelly twins and not Kornienko. While there are astronauts that have accumulated nearly three years in space, none have accumulated an entire year in one mission. The results are tremendously important considering that future crewed missions into the deep solar system could last 3 to 5 years.
4. SpaceX Achieves Upright landing of Launch Vehicle First Stage
IMAGE: Falcon 9 Launch and Landing Streak | 2015 | SpaceX
After a series of failed attempts to land a booster rocket upright after launch and the loss of a rocket shortly after launch earlier this year, SpaceX hit a two-run homer this month with the successful launch of the Orbcomm 3 satellite suite and the first successful upright landing of the rocket booster in the same mission. This is a critical accomplishment and milestone that not even NASA has been able to do - cutting the cost of space access by re-using launch vehicles instead of throwing away the perfectly reusable boosters after a single launch. SpaceX’s ultimate goal is to pave the way for inexpensive transport of humans and equipment to Mars for exploration.
5. Rosetta Spacecraft Catches a ride on Comet 67P
IMAGE: Comet on 11 September 2015 - NavCam | 2015 | ESA/Rosetta/NAVCAM - CC BY-SA IGO 3.0
After a very bumpy and altogether uncertain landing, the Rosetta spacecraft and its orbiting companion brought us unprecedented images and data about the structure and dynamics of the comet’s nucleus. Rosetta’s free ride around the sun marks the first time astronomers have been able to test surface temperature, surface composition, internal composition, and density directly on the surface of a comet.