Astro Watch

SpaceX Launches Two All-electric Communications Satellites Posted: 02 Mar 2015 03:49 AM PST SpaceX’s Falcon 9 rocket delivered the ABS 3A and EUTELSAT 115 West B all-electric satellites to a supersynchronous transfer orbit. Marking Falcon 9’s sixteenth launch and the vehicle’s most voluminous payload to date, the liftoff occurred at 10:50 p.m. EST from SpaceX’s Launch Complex 40 at Cape Canaveral Air Force Station, Fla. Liftoff occurred at the front of the launch window, with Falcon 9’s nine Merlin 1D engines putting out 1.3 million pounds of thrust, rising to 1.5 million pounds as the stage climbed out of Earth’s atmosphere. Approximately three minutes into flight, the first stage engines cut off and the first and second stages separated. Shortly thereafter, the second stage’s single Merlin Vacuum engine ignited to complete a five-minute burn. Twenty-five minutes into flight the engine restarted to complete a one-minute burn to bring the satellites to orbit.  “We are delighted to see EUTELSAT 115 West B on its way into space and thank SpaceX for this successful launch. With this satellite we are trailblazing a new era of electric propulsion for orbit raising that opens opportunities for greater efficiency and higher competitivity. It’s another first in Eutelsat’s 30-year track record of innovation that propels our industry onto the next stage,” said Michel de Rosen, Eutelsat Chairman and CEO.  Thirty minutes into flight, the ABS 3A satellite deployed into a supersynchronous transfer orbit followed by EUTELSAT 115 West B approximately five minutes later.    The rocket and payload went vertical on the launch pad on Saturday, February 28.  The satellites will now fire their thrusters to reach geosynchronous orbits. As the world’s first all-electric propulsion satellites, they carry no liquid propellant – rather, they reach orbit entirely via a lighter and more efficient electric propulsion system. ABS 3A will be located at 3° West and will connect the Americas, Europe, Africa and the Middle East. EUTELSAT 115 West B will be located at 114.9° West and will provide coverage from Alaska and Canada to South America.  “The EUTELSAT 115 West B satellite will transform the service we can offer clients delivering data services that include broadband, cellular backhaul, VSAT solutions and social connectivity. In addition to delivering high-performance C and Ku-band capacity, our footprint will extend beyond Latin American markets into Canada and Alaska. Tonight’s launch reaffirms us more than ever as the satellite company of reference for the Americas,” said Patricio Northland, CEO of Eutelsat Americas.  Constructed by Boeing Satellite Systems, both spacecraft are based on the company’s new BSS-702SP bus.  Half of the weight of most communications satellites is taken up with fuel, sometimes carrying up to 5,000 pounds of liquid propellant for in-space maneuvers. The innovation of the Boeing 702SP allows satellite operators to order smaller spacecraft that can host extra communications capacity to replace the mass freed up with the removal of the fuel tanks, said Mark Spiwak, president of Boeing Satellite Systems International Inc.  “By launching the satellites as a pair, Boeing customers can save on launch costs while benefitting from the company’s highly capable and flexible platforms to meet their mission requirements,” Spiwak said.  SpaceX’s next launch is targeted for approximately three weeks from now, from Cape Canaveral, Fla. Credit: spacex.com, boeing.com, eutelsat.com, spaceflightnow.com

Hunting Transiting Exoplanets Posted: 01 Mar 2015 02:33 PM PST European Southern Observatory (ESO) gears up for the exoplanet hunting. The Next-Generation Transit Survey (NGTS), a wide-field observing system made up of an array of twelve telescopes was installed at ESO’s Paranal Observatory in Chile. It will search for transiting exoplanets — planets that pass in front of their parent star and hence produce a slight dimming of the star’s light that can be detected by sensitive instruments. “NGTS will have some sensitivity to habitable zone planets - these are planets at the right distance from their star that they would receive similar amounts of heat as the Earth does,” Don Pollacco of the University of Warwick (UK) toldastrowatch.net. Pollacco helped build the NGTS. His research interests are primarily in the area of extra-solar planets. He was responsible for the SuperWASP instrument on La Palma which, along with its sister facility at SAAO, has become the most successful ground based planet detection experiment. NGTS will focus on discovering Neptune-sized and smaller planets, hopefully habitable. The telescopes are designed to operate in a robotic mode and it will continuously monitor the brightness of hundreds of thousands of comparatively bright stars in the southern skies. It is searching for transiting exoplanets and will reach a level of accuracy in measuring the brightness of stars — one part in a thousand — that has never before been attained with a ground-based wide-field survey instrument. NGTS also benefits from hardware and software heritage from the SuperWASP project, which since 2004 has been the world's leading in the discovery of transiting exoplanets of Jupiter size. The discoveries of NGTS will be studied further using other larger telescopes, including the ESO Very Large Telescope. One goal is to find small planets that are bright enough for the planetary mass to be measured. This will allow planetary densities to be deduced, which in turn provides clues about the composition of the planets. It may also be possible to probe the atmospheres of the exoplanets whilst they are in transit. During the transit some of the star’s light passes through the planet’s atmosphere, if it has one, and leaves a tiny, but detectable, signature. So far only a few such very delicate observations have been made, but NGTS should provide many more potential targets. “In the case of NGTS there will a mixture of relatively nearby stars and some slightly more distant, although not as distant as Kepler. The transit technique works when a planet moves across the face of its star,” Pollacco said. Pollacco is currently also the UK-spokesperson for the ESA CHEOPS mission - which will be concentrating on the transit characterization of small planets around bright stars found by radial velocity surveys, a science team member of the NASA FINESSE mission which aims to survey exoplanet atmospheres if selected starting in 2017 and the ESA PLATO mission for which he is the Science Coordinator. PLATO will do transit detection of rocky planets in the habitable zones of solar and nearby stars, allowing us to understand processes important in planet formation and evolution. “ESA has recently selected the mission PLATO for launch in 2024 and this has the detection of habitable zone terrestrial planets around sun-like stars as one of its main science drivers,” Pollacco said. “There are other missions that have attempted to do this but while they have candidates, they are so distant that confirmation or any other follow up observations are very difficult. The PLATO planets will be much closer.” The NGTS Consortium is composed of the University of Warwick, UK; the Queen’s University of Belfast, UK; the University of Leicester, UK; the University of Cambridge, UK; Geneva University, Switzerland and DLR Berlin, Germany. The NGTS data will flow into the ESO archive system and will be available to astronomers worldwide for decades to come.

'Cable Guys' Finish Spacewalk Trilogy Posted: 01 Mar 2015 12:09 PM PST NASA astronauts Terry Virts and Barry Wilmore ended their spacewalk at 12:30 p.m. EST with the repressurization of the Space Station's Quest airlock. Virts and Wilmore completed installing 400 feet of cable and several antennas associated with the Common Communications for Visiting Vehicles system known as C2V2. Boeing’s Crew Transportation System (CST)-100 and the SpaceX Crew Dragon will use the system in the coming years to rendezvous with the orbital laboratory and deliver crews to the space station. They completed one additional task to retrieve a bag to cover equipment on the outside of the station. The 5-hour, 38-minute spacewalk was the third for Virts and the fourth for Wilmore. It was the quickest succession of spacewalks since NASA's former shuttle days. Virts has now spent 19 hours and 2 minutes outside during his three spacewalks. Wilmore now has spent 25 hours and 36 minutes in the void of space during his four excursions. Virts and Wilmore installed two sets of antennas Sunday, as well as 400 feet of cable for this new communication system. It was complicated, hand-intensive work, yet the astronauts managed to wrap up more than an hour early Sunday, for a 5 ½-hour spacewalk. Their three outings spanned 19 hours. "You guys have done an outstanding job," Mission Control radioed, "even for two shuttle pilots." "It's amazing ... to see how far we've come from the very first steps outside," Virts said. On Sunday — just like Wednesday — a little water got into Virts' helmet once he was back in the air lock and the chamber was being repressurized. Virts said it seemed to be about the same amount of water, maybe slightly more, but dried quickly. He didn't need any towels this time when his helmet came off. "I couldn't feel it on my skin. I could just see the thin film on the visor," he told Mission Control. Engineers concluded last week it was the result of condensation during the repressurization of the air lock, and a safe and well understood circumstance that had occurred several times before with the same spacesuit. Spacewalker Terry Virts works outside the Quest airlock. Credit: NASA TV Virts was never in danger either day, according to NASA, and no water leaked into his helmet while he was outdoors. Wilmore's much newer suit functioned perfectly during the first two spacewalks, but on Sunday morning, a pressure sensor briefly malfunctioned before he floated out. A mechanical gauge, however, was operating fine. Mission Control instructed Wilmore to pay extra attention to how his suit was feeling. Wilmore is due to return to Earth next week following a 5 1/2-month mission. Virts is midway through his expedition. Russian Soyuz spacecraft carried them both up, with NASA paying for the multimillion-dollar rides. Crews have now spent a total of 1,171 hours and 29 minutes conducting space station assembly and maintenance during 187 spacewalks. Credit: NASA, AP