《SpaceX ready to resume cargo missions to the space station》

  • 来源专题:中国科学院紫金山天文台科技信息监测服务
  • 编译者: zhoubz
  • 发布时间:2016-04-12
  • A SpaceX Falcon 9 stands on the pad at Cape Canaveral, Florida, in advance of the planned April 8 launch of a Dragon cargo spacecraft to the ISS. Credit: SpaceXPHOENIX — SpaceX is prepared to launch its first cargo mission to the International Space Station since a June 2015 launch failure, a mission that will bring to the station both experiments and a prototype expandable module.

    At a pre-launch press conference at NASA’s Kennedy Space Center April 7, officials with NASA and SpaceX said there were no issues preventing a launch of an upgraded Falcon 9 at 4:43 p.m. Eastern April 8 on the company’s eighth commercial resupply mission to the station.

    Hans Koenigsmann, vice president of flight reliability at SpaceX, said the company had completed a launch readiness review for the mission and was not working any problems. Forecasts predict a 90 percent chance of acceptable weather at launch time, as well as if the launch slips to Saturday.

    The Dragon is carrying more than 3,100 kilograms of cargo for the ISS, including a mix of crew supplies, science experiments and station hardware. The experiments carried to the station, some of which will return to Earth on the Dragon in May, include a particular emphasis on various biological experiments. The mission, said Kirt Costello, deputy chief scientist of the ISS at NASA, “is an amazing bonanza for the biological sciences.”

    The largest single item on the mission, though, is the Bigelow Expandable Activity Module (BEAM), a prototype expandable module developed by Bigelow Aerospace. While NASA plans to use BEAM to test expandable technologies for potential future use in deep-space habitats or Mars missions, Bigelow sees BEAM as a testbed for its much larger expandable habitat modules it is developing.

    “It is an important step for us, it really is, that NASA has the confidence in our little company to be able to do this,” said Robert Bigelow, president of Bigelow Aerospace, at a NASA briefing. “We are excited about this opportunity.”

    Bigelow said that a successful test of BEAM on the ISS would keep the company on track to deploy its first space station by 2020. That facility would consist of two of the company’s B330 modules, each with 330 cubic meters of volume, docked to each other. The company would lease the station to companies or countries that want to perform research or other activities in low Earth orbit.

    While BEAM is designed primarily for NASA’s use to test the environment inside the expandable module, Bigelow suggested that the module, about five percent the size of a B330, might also be used for commercial activities.

    “We have four different groups today that want to fly experiments and different payloads to BEAM,” he said. Two of those are companies and two are national agencies, although he did not identify them. “We hoping that, maybe in half a year or something, we can get permission from NASA to accommodate these people in some way.”

    For SpaceX, the launch is another opportunity to attempt to recover the Falcon 9 first stage with a landing on a “drone ship” in the Atlantic Ocean downrange from the launch site. Four previous attempts to land the stage on the ship, including on two launches earlier this year, have all failed.

    Koenigsmann said they’ve worked to improve the odds of a successful landing, including making fixes to the landing legs to avoid a repeat of a January landing attempt where the stage touched down on the ship, only to fall over and explode after one of the legs collapsed. “I certainly hope that we’re going to nail the landing this time,” he said.

    He added SpaceX had the option of trying to bring the stage all the way back to Cape Canaveral, similar to the successful landing the company performed on a December launch. “On this particular flight, we decided we wanted to go to the drone ship and see if we can get a successful landing on the drone ship,” he said, in part because upcoming launches only have the option of a drone ship landing given the nature of their missions. “It’s a good opportunity for us to refine our drone ship landing capabilities.”

    Koenigsmann added that he believed SpaceX had worked out issues with the use of “densified” propellants in the upgraded Falcon 9, where liquid oxygen and kerosene are cooled to increase their density and improve the vehicle’s performance. Problems with liquid oxygen in particular contributed to several delays in the previous Falcon 9 launch.

    “I’m pretty sure we’ve learned the most of it,” he said. “I feel like we’ve got this relatively well under control in this point in time.”

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  • 《Dragon ‘caught’ at International Space Station》

    • 来源专题:中国科学院紫金山天文台科技信息监测服务
    • 编译者:zhoubz
    • 发布时间:2016-04-12
    • April 10th, 2016 An archive photo of a previous Dragon berthed at the International Space Station. Photo Credit: NASA Two days after a textbook launch, SpaceX’s CRS-8 Dragon cargo ship rendezvoused and was berthed to the International Space Station (ISS). Capture by the space station’s robotic Canadarm2 took place at 6:23 a.m. CDT (11:23 GMT) April 10 about 250 miles (402 kilometers) above the Pacific Ocean just west of Hawaii. Controlling the arm was Expedition 47 Flight Engineer and European Space Agency (ESA) astronaut Tim Peake. He, along with NASA astronaut Jeff Williams, monitored the approaching vessel from the Cupola window. A Falcon 9 launched with the CRS-8 Dragon at 4:43 p.m. EDT (20:43 GMT) April 8 from Cape Canaveral Air Force Station’s Launch Complex 40. Photo Credit: Michael Howard / SpaceFlight Insider “It looks like we caught a Dragon,” Peake said after capture. Then, over the next two hours, ground teams controlled the arm to move Dragon from its capture point just 33 feet (10 meters) below the station to the Earth-facing port of the Harmony module. The command to automatically drive four bolts in the Common Berthing Mechanism connecting Dragon and Harmony was given at about 8:55 a.m. CDT (13:55 GMT). The stations computer rejected the command at first, but upon trying a second time, it accepted and the spacecraft was officially berthed to the ISS at 8:57 a.m. CDT (13:57 GMT)—some 40 feet (12 meters) from the OA-6 Cygnus cargo ship attached to the Unity module. This marks the first time two commercial vehicles were at the station at the same time. Dragon arrived just outside the station’s “Keep-out Sphere”—an area of about 656 feet (200 meters) around ISS—about 30 minutes later than originally planned. This was due to greater than expected atmospheric drag on the spacecraft’s solar panels resulting in correction burns by the vehicle’s Draco thrusters. The cargo ship reached the 820-foot (250-meter) hold point at about 5 a.m. CDT (10:00 GMT). This allowed for verification that the spacecraft had established a two-way UHF communications link with the space station. Flight controllers reduced the amount of time at this hold point, and a little over five minutes later, the spacecraft resumed its careful approach to the orbiting outpost. About 30 minutes later, Dragon was 98 feet (30 meters) from ISS. Ground teams in Houston and SpaceX headquarters in Hawthorne, California, were polled to verify everything was still “GO” for final approach and capture. Additionally, Williams could evaluate the ship to verify it was in the correction position and issue a hold, abort, or retreat in the event of a problem. However, everything was nominal and the approach continued until Dragon was just 33 feet (10 meters) below the Destiny lab. At 6:22 a.m. CDT (11:22 GMT) Peake manually controlled the arm to the grapple fixture on Dragon. A minute later, contact was made. The arrival of Dragon marked only the second time in the history of the space station program that six vehicles were docked or berthed to the outpost. The last time was in 2011 when Space Shuttle Discovery was docked with the complex on mission STS-133—that orbiter’s final flight. That was also the only time all of the originally planned government-owned vehicles (Space Shuttle, Soyuz, Progress, Japanese HTV, and the European Space Agency’s ATV) were at the station at the same time. This is the eighth Dragon to visit the space station—the first since the ill-fated CRS-7 mission. It is also the 84th uncrewed cargo ship and 170th overall mission to reach the orbiting laboratory. The hatch between the cargo ship and space station will be opened early Monday morning. In the next three weeks, Dragon’s 7,000 pounds (3,175 kilograms) of food, supplies, and experiments will be unloaded and dispersed throughout ISS. Additionally, the vessel will be reloaded with trash and unneeded equipment to be returned to Earth. On April 16, CRS-8’s most notable cargo, the Bigelow Expandable Activity Module (BEAM) will be robotically removed from the unpressurized trunk of the spacecraft and attached to the aft port of the Tranquility module. It will be expanded sometime in late May. Dragon is expected to remain attached to the space station until May 1 of this year (2016).
  • 《Triumph! SpaceX returns Dragon to service with CRS-8, nails landing on Drone Ship》

    • 来源专题:中国科学院紫金山天文台科技信息监测服务
    • 编译者:zhoubz
    • 发布时间:2016-04-12
    • At approximately 4:52 p.m. EDT (20:52 GMT), SpaceX successfully carried out a landing on the “Of Course I Still Love You” Autonomous Spaceport Drone Ship positioned out in the Atlantic Ocean. Image Credit: SpaceX CAPE CANAVERAL, Fla — The hits kept right on coming for SpaceX today as the NewSpace firm successfully returned their Dragon spacecraft to service and carried out the first completely successful ocean landing in the company’s history when at approximately 4:52 p.m. EDT (20:52 GMT) the Falcon 9’s first stage successfully touched down on the “Of Course I Still Love You” Autonomous Spaceport Drone Ship (ASDS) positioned out in the Atlantic. SpaceX launched the CRS-8 mission to the International Space Station (ISS) on April 8, at 4:43 p.m. EDT (20:43 GMT). The launch site for the mission was Cape Canaveral’s Space Launch Complex 40 (SLC-40) in Florida. 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This technology demonstrator will further studies that have been and are underway into the concept of inflatable habitat modules—something of keen interest to NASA who is hoping to get back into the business of sending astronauts far beyond the orbit of Earth. In terms of the crew on board the space station, they will spend very little time in BEAM. NASA and Bigelow Aerospace have stated crews will only enter the habitat about three times per year during the its planned two year stint attached to the outpost. Although it is possible that astronauts on the ISS might spend more time in the hab, at present, they’re only slotted to spend three to four hours in the module during each visit. As is the case with any research done on orbit, mission planners first have to get their experiments out of Earth’s gravity well. That took place under mostly-clear skies which granted a 90 percent chance of favorable conditions for launch. Photo Credit: Jared Haworth / We Report Space “The rodents on our experiment will stay on the station for about six weeks, coming back with the CRS-8 Dragon,” NASA Ames Research Center’s Dennis Leveson-Gower told SpaceFlight Insider. “It’s thrilling to see your experiment go up, our team has been really been working hard on this … it’s really exciting to see it go off on the first day that it was scheduled.” On the afternoon of Thursday, April 7, Dragon was loaded with what is known as “late load” cargo in preparation for the launch attempt. Some 38 minutes before the launch was scheduled to take place, the launch conductor carried out a readiness poll. This was followed three minutes later with the fueling of the Falcon 9 FT began. The two-stage rocket is fueled by a mixture of RP-1 (a highly-refined version of kerosene) and liquid oxygen (LOX). 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