After several delays, including twice over the past week, the space shuttle Discovery has finally been launched into space. The spacecraft took off at precisely 7:43 p.m. EDT, embarking on the STS-119 mission, which will provide the International Space Station (ISS) with the fourth and final set of solar arrays. The shuttle will also deliver to the ISS its newest crew member – Japan’s Aerospace Exploration Agency astronaut Koichi Wakata, who will replace flight engineer Sandra Magnus at the station.
With the addition of two new international partner laboratories to the ISS the European “Columbus” and the Japanese “Kibo” and the immanent expansion of its crew, the station, which soon will be home to six astronauts, requires more electricity to power its on-board facilities and equipment. “More crew means that we’ll have to run more life support equipment, more crew support equipment – toilet facilities, water processing equipment and all of that stuff,” said Kwatsi Alibaruho, the lead space station flight director for the mission. “We’ll have to run more of all of that, so we need additional power.”
The solar arrays, which will be delivered by Discovery to the ISS, are comprised of two separate solar array wings, each measuring 115-feet in length. Combined, these arrays can generate 84 to 120 kilowatts of electricity – that’s enough to power more than 40 average homes. Apart from the space station’s routine operational needs, this electricity will also be used for the many scientific experiments, which are planned to be conducted at the ISS. “We’re able to do a lot of things in our current configuration, and we’re not too power limited,” Alibaruho said. “But we still have some other things to get on orbit. We don’t have the Columbus module and the Kibo module completely full of experiments, the way we expect to have it in coming years. So we need the additional power capability to be able to expand the science capability.”
The latest truss segment with solar array wings is to be installed on the far right side of the station’s starboard truss. Such a task requires the space station’s robotic arm to extend almost to its full length, being left with very little room to maneuver – this complicates matters for the astronauts. “We’ve done it before, but we haven’t done it with these exact same people,” Discovery’s commander, Lee Archambault, said. “But there are some very good lessons learned out there, and we’ll certainly capitalize on those.”
Another challenge for the crew will be to properly unfold the solar arrays – in a previous installation during the STS-97 mission, the plastics and polymers that coat the panels of the solar arrays stuck together, eventually causing one of the arrays to tear. NASA engineers have since worked their way around this problem, and the agency says it is unlikely that the same issue will arise again. Nonetheless, Discovery astronauts remain alert – “It’s always the thing that you think you have down, that’s routine, that comes back and bites you,” said Paul Dye, lead shuttle flight director. “It’ll either be routine or it will be heart stopping, like always.”
The STS-119 mission, which is scheduled to last 15 days, will include four spacewalks. This, according to NASA, is at least three times more than what is actually needed to complete the solar arrays installation. The agency says the additional time can be used to perform other tasks, which aren’t immediately necessary, but are needed to be done sometime in the not-so-distant future. Such errands include everything from deploying cargo attachment systems on the starboard truss to installing a GPS antenna that will help guide the Japanese H-II Transfer Vehicle to the station later in the year. “There’s a great potential to have some issues that we may need some additional spacewalking time to go alleviate,” Alibaruho said. “This mission is structured in such a way that we could conceivably go address them without necessarily having to extend the mission or add a spacewalk.”
Archambault says he is particularly looking forward to taking a look at the space station after its last solar array wings have been installed. “This will be the first time we get a flyaround with imagery of the space station looking about what it’s going to look like in its final configuration,” he said. “We’ve still got to install Kibo’s external facility and Node 3 with its cupola further on. But for all intents and purposes, 99 percent of it is going to look just like the plans after we get out of there.”
TFOT has routinely covered NASA’s various missions – among our most recent articles, you can find coverage of the Kepler telescope, which was recently launched in search of Earth-like planets in our galaxy. You can also check out our articles on previous Space Shuttle Endeavour and the Discovery Space Shuttle missions. You are also welcome to take a look at an article on a new galaxy formation theory, recently proposed by scientists of the Hebrew University in Jerusalem.
More information on the STS-119 mission can be found here.
