This has been a busy year in space, with rovers roving on Mars and the first landing on the Moon in 40 years, the search for life beyond our Earth heating up, and 3D printing moving into orbit. As a Chinese rover explores the lunar surface and astronauts work to repair the International Space Station (ISS), Gizmag looks back on the space highlights of 2013.
Voyager 1 hits interstellar space
Milestone is a word that gets tossed around a lot these days, but this year we learned that the human race has passed what could be the biggest milestone since fish decided to have a go at living on dry land. In September, NASA confirmed that Voyager 1 was the first manmade object to enter interstellar space.
According to the space agency, the unmanned probe passed out of the influence of the Sun on August 25, 2012 after traveling 12 billion miles (19 billion km) – a distance so vast that a radio message from Voyager to Earth takes 17 hours to reach us.
Voyager 1’s next encounter with another celestial body won’t be for 40,000 years when it passes within 1.6 light years of the star Gliese 445 (AC +79 3888), so mark your calendar.
A cosmic bullet graze
2013 saw the Earth have its closest call since the Tunguska impact in 1908 made a mess of a large part of Siberia. On February 15, the Chelyabinsk meteor exploded over Chelyabinsk, Russia in a fireball that was brighter than the Sun, was seen by thousands, recorded by dashboard cameras all over the region, and heard by scientific listening posts around the world.
When the 20 m (65 ft) diameter meteor exploded, the 500-kiloton blast was 40 times the explosive force of the Hiroshima atomic bomb. The detonation broke windows and damaged buildings. In all, 1,491 people, including 311 children, were injured, 70 cases of flash blindness were reported, and the fireball put out so much UV radiation that many people suffered from sunburn. Small wonder NASA and others suddenly became very interested in asteroid tracking and deflection schemes.
Spaceflight goes commercial
Now that the Space Shuttle is a museum exhibit, the US government is encouraging private companies in partnership with NASA to develop new launchers, cargo ships, and manned spacecraft to handle near-Earth orbit traffic and to move space travel into the private sector instead of merely acting as NASA or Pentagon contractors. This year, that policy began to bear orbital fruit as companies started to send their own craft into space on their own boosters and moved toward even more ambitious projects.
In April, the Orbital Sciences Corporation tested its Antares launcher. The launch, which suffered several delays, was the first from the pad at NASA”s Wallops Flight Facility in Virginia and carried a "mass simulated payload" equivalent to the mass of a spacecraft into Earth orbit. In September, Orbital Sciences’ Cygnus cargo ship docked with the ISS for the first time after a delay due to a software malfunction.
While the Antares launches gave the US east coast a fireworks display, October saw the Sierra Nevada Corporation’s Dream Chaser manned spacecraft take to the skies in its first glide test. The Shuttle-like space ferry’s flight was successful, though it did bend a bit of the undercarriage on landing.
SpaceX’s Dragon cargo ship made its second commercial run to the ISS in March, so its visits are starting to seem almost routine. But the company did break new ground when the first version of its reusable Grasshopper rockets carried out a series of vertical takeoffs and landings, achieving new altitude records before retiring in October.
Meanwhile, the usually publicity shy Blue Origins project test fired a new engine for its manned orbital launch vehicle in November. The BE-3 liquid hydrogen engine is the first of its type to be produced since the RS-68 engine for the Delta IV booster went into service in 2002. The engine is a key component in the Blue Origins Reusable Booster System, which will allow the spacecraft to fly again rather than be disposed off after one mission, as is the case with the Russian Soyuz.
Of course, not all commercial spaceflight efforts have the ISS as their destination. Virgin Galactic is more interested, for now, at going after the tourist market. 2013 was the year that Sir Richard Branson’s SpaceShipTwo suborbital sightseeing craft carried out successful powered tests as the company gears up for carrying its first paying passengers. The company even found the time to sign a contract with the US NBC network for television coverage of SpaceShipTwo’s maiden flight.
The search for life
The question of whether or not life exists elsewhere in the Universe had a bit more light shed on it this year as scientists looked for evidence in the Solar System and beyond. Close to home (give or take a hundred million miles), Mars provided a mixed bag regarding life on the Red Planet, with a disappointing find following hot on the heels of nearly every optimistic discovery.
This year, NASA’s Curiosity rover completed its commissioning and settled down to months of exploration. On February 6, the nuclear-powered explorer conducted the first drilling ever attempted on Mars and on February 9 it collected its first drilling sample. These drillings are key to looking for signs of past or present life because the surface environment of Mars is too hostile for life to exist, so scientists must seek out samples inside of bedrock materials.
An exciting feature of Curiosity’s first drilling operation was that beneath the dead, reddish surface of the John Klein rock where the sample was taken, there was a gray interior that it is not harshly oxidizing, acidic or extremely salty. The presence of calcium sulfate indicates that the rocks are neutral or mildly alkaline. Furthermore, the lack of oxidizing chemicals indicates that the interior of the rocks have a much steeper energy gradient, which could power life.
That might have raised hopes of finding life, but in September Curiosity dashed said hopes of finding any life on Mars when it detected no methane on the planet after more than a year of extensive testing using the its Sample Analysis at Mars (SAM) laboratory. Since methane is a key indicator for the presence of biological activity, its absence throws into question the notion that there may be life on Mars today.
On the other hand, Curiosity and NASA’s Mars Reconnaissance Orbiter did find promising signs of abundant water on Mars in its ancient past. The Orbiter found new evidence of a wet underground environment that once existed on the Red Planet. Using its Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), the orbiter examined the floor of McLaughlin Crater in the Northern Hemisphere of the planet and found evidence of the formation of carbonates and clay in a groundwater-fed lake in the ancient past.
Once you’re outside the Solar System, the quest for life is more like a search for real estate. That’s because the first step for finding life on other worlds is finding other worlds. To be specific, you need rocky worlds about the size of Earth where the temperature isn’t too hot or too cold for liquid water to exist. This is known as the habitable or Goldilocks zone.
The biggest gun in this hunt has been NASA’s Kepler space telescope. Before its extended mission was cut short due to the loss of a pair of reaction wheels, the planet-hunting probe found hundreds of extrasolar planets and thousands of candidates.
In April, NASA announced that Kepler had discovered two planetary systems with the smallest planets yet found that lie in the habitable zone; including three super-Earth size planets. One of these is a habitable-zone exoplanet that is the closest in size to Earth yet discovered.
Kepler was not only able to show that potentially habitable planets exist, but something of their nature. For example, astronomers used data from NASA's Kepler and Spitzer space telescopes to map the first clouds discovered on an extrasolar planet.
How many of the 200 billion stars in our galaxy have potentially habitable planets? Kepler gave us a clue about that, too. University of California Berkeley and University of Hawaii astronomers carried out a study using data from Kepler to provide part of the answer, that one in five Sun-like stars may have Earth-size planets that could support life.
In recent years, Earth's attitude toward the Moon has been a bit like New Yorkers' toward the Statue of Liberty; they know it's there, but can't be bothered to visit it. That changed in 2013 as China flexed its growing space muscle when its Chang'e-3 lunar lander touched down on December 14. On board the unmanned craft was the Yu Tu (Jade Rabbit) robotic lunar rover, which is currently seeing the sights of Mare Imbrium. It’s not only China’s first lunar landing, but the first by any country, not counting impacts, since the Soviet Luna 24 mission in 1976. It's also the first Lunar rover since Lunokhod 2 in 1973.
The ISS has become home to a surprising number of robots, from flying balls to gigantic robotic arms for juggling incoming and outgoing spacecraft, but some of the newer arrivals look more like George Lucas had a hand in their design. One of these is Toyota’s Kirobo robot; a cute little automaton that arrived on board the space station in August and sent back greetings to Earth in Japanese that translated as "On August 21, 2013, a robot took one small step toward a brighter future for all."
A larger and, at first glance, more frightening robotic crew member on the ISS is Robonaut 2, which is a humanoid robot – or rather, half of one, since it’s a torso bolted to a stanchion. It’s been carrying out tests on the station throughout the year and now NASA has made it a pair of legs. When these are installed early next year, Robonaut will be able to move about inside the station on its own.
For everyone from the hobbyist to the industrialist, 3D printing has been the buzzword of 2013. Not surprisingly, this technology caught the attention of space engineers for whom the idea of printing a component in orbit is a lot better than going through the trouble of sending up a spare from Earth. This year, a 3D printer compatible with a weightless environment was approved by NASA to fly to the ISS in 2014 for tests. Not to be outdone, the ESA is sending up one of its own that can print metal components.
For the earthbound space engineer, 3D printing of rocket components has migrated quickly from the laboratory to the shop floor. The technology has come so far in so short a time that even students at the University of California, San Diego have built a metal rocket engine and conducted the first hot fire test of a printed liquid-fueled, metal rocket engine by any university in the world.
Launchers and propulsion systems
The biggest obstacle facing space travel is coming up with a propulsion system that is capable of moving payloads at high speed for little cost. In 2013, one contender, the ion thruster, clocked up 48,000 hours, or five and a half years, of continuous operation. Developed under NASA's Evolutionary Xenon Thruster (NEXT) project, the engine now holds the record for the longest test duration of any type of space propulsion system.
A rocket that can fire for over five years may seem impressive, but what about getting rid of the rocket altogether and just hurling payloads into orbit? HyperV Technologies Corporation of Chantilly, Virginia unveiled its version of this idea with a "mechanical hypervelocity mass accelerator" called the Slingatron.
As the name implies, it works on the principle of a slingshot and by means of ultrafast gyrations. If it is ever built, it could drastically cut the costs of getting payloads into space. Don’t expect to book a ticket on one, however. The system produces G-forces so strong that they would turn passengers into paté.
At the other end of the scale is an elegant little system that was tested inside the ISS. Called the Resonant Inductive Near-field Generation System (RINGS), it uses magnetic fields to move spacecraft as a way to increase service life and make satellite formation flying more practical. Exactly how practical it turns out to be is a question for engineers, but seeing a pair of, well, RINGS floating about in a cosmic ballet would be a sight worth seeing.
All this bodes well for 2014, which will no doubt continue to amaze and inspire those of us standing on solid ground with one eye on the heavens.