The Falcon Flies Again
The next SpaceX Commercial Resupply Services mission (CRS-6) to the International Space Station is scheduled for an instantaneous launch window at 1:33 p.m. PDT on Monday, April 13. “Instantaneous” means that SpaceX’s Falcon-9 rocket must launch precisely on time. Any delay at all will scrub the launch, with the next opportunity the following day, Tuesday at 1:10 pm PDT. After a successful launch, the Dragon space capsule, packed with more than two tons of supplies, will rendezvous with the space station two days later, to be snagged by the station’s robotic arm. An astronaut operating the arm will then maneuver Dragon to a berthing port.
As the mission designation indicates, this will be Dragon’s sixth operational flight to the space station, and SpaceX’s sixteenth Falcon launch overall, building upon the company's record of successes and bold innovation. One such innovation is recovery and reuse of the Falcon rocket’s first stage. When early recovery tests using parachutes proved impractical, SpaceX opted in 2011 to develop propulsive landings as a more economical strategy. After the first failed attempt during the CRS-5 mission in January to land the rocket on a robotic landing barge named “Just Read the Instructions,” SpaceX is ready to try again Monday under (hopefully) better weather and ocean conditions and a (definitely) bigger supply of hydraulic fluid to control its steering fins.
(In between CRS-5 and -6, another landing test took place: unfortunately, the mission to launch the DSCOVR satellite took place during bad weather, making the barge too unstable for a landing. Although SpaceX cancelled the attempt to touch down on the barge, it took advantage of the opportunity to make a powered return and least steer to within 10 meters of the platform.)
Reusability is a key goal for SpaceX, which has set its sights on reducing the cost of spaceflight. Company founder and CEO Elon Musk states that he will consider the company’s efforts to have failed unless they can reuse rocket components, ultimately planning to apply the principle to larger and larger boosters. –Bing Quock
Name a Feature on Pluto!
On July 14, NASA’s New Horizons mission will make the first-ever close flyby the dwarf planet Pluto. The spacecraft will pass Pluto at a speed of 31,000 mph (50,000 kph), taking thousands of images and making a wide range of science observations. At a distance of nearly four billion miles from Earth at flyby, it will take approximately 4.5 hours for data to reach Earth.
What will New Horizons discover on the planet’s surface? Scientists are uncertain, but we could see craters, mountain ranges, valleys, volcanoes, collapsed basins—a wide range of physical features. And all of them will need names. And the International Astronomical Union (IAU) wants your help!
Between now and April 24, you can vote for your favorite names from a list officially sanctioned by the IAU. You can choose from lists of explorers, scientists, and science fiction authors, with categories for spacecraft and fictional names and places, and a special ballot just for kids. And don’t forget Pluto’s moon Charon! Its features will need names, too
As you select names from cultures around the globe, you can also learn about them… and help astronomers at the same time! Even if you don’t have a chance to vote, mark your calendars for April 25, when you’ll have a chance to meet New Horizons scientists and engineers at the Academy’s annual Astronomy Day celebration! –Molly Michelson
Great Green Cosmic Clouds
The good folks at the Space Telescope Science Institute and the University of Alabama—along with citizen scientists at their home computers—have noticed odd features wrapped around a few select and very distant galaxies.
Far from the central core of these huge groups of stars, the Hubble Space Telescope has observed softly glowing, wispy green clouds, comprised mostly of oxygen. At first, one might think that the light from the galaxies’ stars illuminates these clouds, but there’s not enough stellar energy to do the job. Instead, astronomers suspect that the energy comes from a far stranger source—long dead quasars!
Short for QUAsi-StellAr Radio Sources, quasars emit exceedingly bright beams of electromagnetic radiation as material falls into a black hole. It might seem a bit counterintuitive, but as material falls in, a small amount of matter is exchanged for a large amount of energy, which is emitted from the poles of the black hole. When they were first observed in the 1950s and 60s, these lighthouse-like objects were so bright that astronomers assumed that they were nearby—at least in a cosmological sense, only a few hundred to a few thousand light years away! But as the nature of quasars was better understood, astronomers began to realize that these objects were farther away than the most distant galaxies that had been observed at that time. They gave off so much energy that even from this great distance they were still observable in radio waves.
The active galaxies with green wisps do not seem to harbor quasars in their cores—or at least, not any more.
“The quasars are not bright enough now to account for what we’re seeing; this is a record of something that happened in the past,” said Bill Keel of the University of Alabama, Tuscaloosa. “The glowing filaments are telling us that the quasars were once emitting more energy, or they are changing very rapidly, which they were not supposed to do.”
So, tens of thousands of years ago, the light radiated from the quasars at the centers of the galaxies in question illuminated these structures, which we now see glowing in the green light of oxygen emission.
And where did the wispy structures themselves come from? Perhaps from a merger of galaxies, which could also have ignited the central quasar. Thus, we’re seeing the remnants of a long-ago galactic collision illuminated by the energetic light source created by the collision itself. –Josh Roberts
Images: Hubble, NASA and ESA; Pluto, NASA/JHU APL/SwRI/Steve Gribben