Wednesday, July 30, 2014

ESA aims for an historic blaze of glory for ATV-5



     The European Space Agency (ESA) plans to transmit interior views of destruction from a de-orbiting spacecraft when it concludes its fifth and final mission for their Automated Transfer Vehicle (ATV) early next year. ATV-5 successfully launched atop an Arianespace heavy-lift Ariane 5 rocket last night, July 29, at 8:44 p.m. GFT (23:44 GMT) from Guiana Space Centre ELA-3 located in Kourou, French Guiana.

     The unmanned pressurized vehicle, also named Georges Lemaître, is now making its way to the International Space Station (ISS). Four control centers — ATV Control Centre located in Toulouse, ISS Mission Control Center in Moscow, ISS Mission Control Center in Houston and Columbus Control Centre in Oberpfaffenhofen, near Munich — will help monitor the progress of ATV-5 along the way. It is scheduled to dock at the aft port of the Russian Zvezda service module on August 12.

     Like the four previous ATV missions, which started with the launch of ATV-1 back on March 9, 2008, the spacecraft will deliver several tons of supplies like water, air, food, fuel, clothing and spare parts, as well as experiments. With about 14,500 pounds of cargo it is, according to ESA TV, the heaviest spacecraft ever launched by Europe. Among the experiments aboard this final ATV mission is special hardware designed to provide never-before-seen views of a spacecraft burning up as it returns to Earth.

     If all goes according to plan, ATV-5 will return in late January 2015. Engineers, led by ESA, have developed the ATV Break-Up Camera (BUC), designed to capture infrared images from within the spacecraft as it’s destroyed when its mission ends. ESA has stated that the team working on the design and testing of this device had to work “at breakneck pace” within the last nine months to finish this unique infrared camera on-time for launch.

     In conjunction with the BUC camera will be Japan’s i-Ball optical camera and NASA’s Re-Entry Break-up Recorder (REBR). All three will work together to give a comprehensive view of the violent destruction awaiting ATV-5 as it reenters Earth’s atmosphere.

     Another addition to this ferry-observation goal is ESA’s Reentry SatCom capsule, designed to store images like an aircraft’s black box, and transmit the data back to Earth after the vessel’s break-up, with the use of an Iridium satellite link.

     “These different instruments will complement each other,” said project leader, Neil Murray, in a statement released by ESA.

     The greatest challenge for this project was to design a capsule that can transmit collected data back to Earth regardless of its position during reentry, and also survive the destructive heat that the hardware will encounter: around 2,732 degrees Fahrenheit (1,500 degrees Celsius).

     There is also a known blackout issue that occurs with spacecraft upon reentry, caused by charged gas particles and friction creating a cone of plasma that surrounds an object when it contacts the atmosphere at high velocity.

     “The Reentry SatCom has an antenna, so that once ATV breaks up it begins transmitting the data to any Iridium communication satellites in line of sight,” said Murray, in the ESA statement.

     “Additionally, signaling will continue after the atmospheric drag has decelerated the SatCom to levels where a plasma is no longer formed — somewhere below 40 km — at a point where Iridium satellites should become visible to it regardless.”

     The BUC camera and other instruments will be installed on a rack at the rear of ATV-5 around five days before it is undocked from the ISS. Until then, crew members aboard ISS will unload around six tons of propellant, supplies and experiments, before loading the spacecraft with waste to be burnt up along with the vehicle when it is purposely deorbited.

     All man-made objects in Earth’s orbit, unless acted upon by elevating thrusters, will eventually meet the same ferry end as ATV-5, even the multi-billion dollar ISS. Part of this final mission for ATV is to better understand what happens to large spacecraft that enter Earth’s atmosphere.

     “The data should also hold broader value,” said Murray. “The project is proceeding under our ‘Design for Demise’ effort to design space hardware in such a way that it is less likely to survive reentry and potentially endanger the public.”

     The July 29 launch of this mission went nominally, marking the 60th successful Ariane 5 rocket launch in a row. ESA Mission Director Jean-Christophe Ronnet declared, “So far, so good,” as final checks were made, and at T-0, the Vulcain 2 engine of the Ariane 5 rocket’s main cryogenic stage ignited. Seven seconds later the solid rocket boosters did the same, and the rocket lifted off the pad.

     The launch vehicle passed Mach 1 at approximately 48 seconds mission elapsed time, passing the speed of sound at an altitude of about 22,600 feet. Just a little more than one minute later, the rocket’s two SRBs separated and were sent tumbling toward the Atlantic Ocean far below. After about another minute, the Ariane 5 was sufficiently far enough beyond Earth’s thick lower atmosphere so as to allow the payload fairing to be jettisoned as well.

     Main engine shutdown occurred at T+8 minutes and 48 seconds, after which the stages separated and the upper stage’s Aestus engine ignited.

     At 17 minutes and 12 seconds into flight, the upper stage shut down temporarily, as planned. It coasted in its “parking orbit” for 42 minutes as it climbed to apogee, performing a series of attitude maneuvers in order to distribute sunlight (and its heat) evenly across its surface.

     It wasn’t until just over 59 minutes into flight that the second and final burn began, during which the spacecraft’s orbit was circularized at an altitude of about 161 miles. With ATV-5 injected into its proper orbit, the upper stage engine shut down again, and the ATV separated from the upper stage to commence its own journey to the ISS. Georges Lemaître is now autonomous, using batteries and four large solar panels for energy along with a GPS and star sensor for guidance, in cooperation with the CNES control center in Toulouse.

     After the announcement of ATV-5 orbital insertion, Stéphane Israël, Chairman and CEO of Arianespace, said: “We are extremely proud of this successful ATV mission, a strong symbol of Europe’s role in this major international program, thanks to two flagship products from our space industry, Ariane 5 and the ATV. I would like to thank our customer, the European Space Agency, for continuing to express its trust in Arianespace, within the scope of our original mandate, namely to guarantee independent access to Space for Europe. I would also like to congratulate Airbus Defense and Space, the prime contractor for these two programs, as well as all other companies involved, for their remarkable work that has driven the success of these complex missions. This year will be decisive for the future of the European space transport industry, so this evening’s success, the 60th in a row for Ariane, is a very timely reminder of our industry’s excellence, and our proven ability for innovation and performance.”

By James Tutten

(Above photo provided by ESA)

(Published at www.spaceflightinsider.com on July 30, 2014.)
http://www.spaceflightinsider.com/organizations/esa/esa-looks-historic-blaze-glory-final-atv-5-mission-iss/

Sunday, July 20, 2014

NASA to ‘hotfire’ test modified RS-25 rocket engine

     Engineers at NASA’s Stennis Space Center installed an RS-25 rocket engine at the facilities A-1 Test Stand this week, and are ready to begin a series of developmental tests on what should be the main power source for NASA’s deep-space launch vehicle, the Space Launch System (SLS ).

     This RS-25 engine, called No. 0525, is a newly modified version of the main engine that was used for more than 30 years on NASA’s iconic space shuttle program. Four of these modified RS-25 engines will power the core stage of NASA’s SLS rocket, and this upcoming testing will be vital to confirm the effectiveness of upgraded engine components and other systems.
     “Installation of RS-25 engine No. 0525 signals the launch of another major rocket engine test project for human space exploration on the A-1 Test Stand,” said Gary Benton, RS-25 rocket engine test project manager at Stennis, in a statement released by NASA.

     The primary system being evaluated is the RS-25’s new advanced engine controller. This internal system acts as an onboard regulator that directs the flow of mixed liquid oxygen and liquid hydrogen fuel, which are the propellents for the rocket. When this engine fires for the first time, and the “hotfire” testing officially begins, the engine controller will also evaluate the high amount of thrust generated, which will be essential to achieving liftoff and traveling beyond low-Earth orbit (LEO).

     “This test series is a major milestone because it will be our first opportunity to operate the engine with a new controller and to test propellant inlet conditions for SLS that are different than the space shuttle,” said Steve Wofford, SLS Liquid Engines Element manager, in a statement released by NASA. “This testing will confirm the RS-25 will be successful at powering SLS.”

     The test stand at NASA’s Stennis Space Center, where engine No. 0525 is currently waiting to be put through its paces, is a historic location for the space agency. It was originally built to test the Apollo-era rocket engines back in the 1960s, and will now be used to develop the engines used for NASA’s next great leap into space.

     SLS will serve as the launch vehicle for NASA’s Orion spacecraft, designed to take humans on future missions that include, the Moon, a captured asteroid, Mars, and beyond.

     Testing is set to begin in the coming weeks, and on top of other successful developmental projects over the decades, this test stand has undergone over a year of modifications to prepare the structure for the RS-25 engine.

     “Another upcoming milestone for SLS is putting the final touches on the Vertical Assembly Center (VAC),” said Rachel Kraft, a public affairs specialist at NASA Headquarters in Washington.

     The VAC will be one of the largest welding tools ever constructed when it’s completed later this year. VAC, along with several other tooling stations located at NASA’s Michoud Assembly Facility in New Orleans, will be used to construct the 321-foot tall SLS rocket body, with a welding technique called “friction stir welding” that creates a nearly seamless surface area.

     When development on all the components and systems for SLS is completed, they will be integrated into the “Block 1 variant” and flown on the first SLS flight-test called Exploration Mission 1, which is currently scheduled for some time in 2017.

By James Tutten

(Above photo provided by NASA)

(Published at www.spaceflightinsider.com on July 20, 2014.)
http://www.spaceflightinsider.com/organizations/nasa/nasa-ready-hotfire-testing-modified-rs-25-rocket-engine-sls/

Wednesday, July 9, 2014

James Webb Space Telescope complets static test



     Developmental progress continues on NASA’s James Webb Space Telescope (JWST) with the successful completion of static testing on its primary mirror backplane support structure (PMBSS). This backplane will serve as the backbone of the observatory and is critical to the image gathering abilities of this highly-anticipated successor to the Hubble Space Telescope.

     “Static testing demonstrates the backplane has the structural integrity to withstand the forces and vibrations of launch and is the final test prior to starting the integration of the backplane with the rest of the telescope,” said Lee Feinberg, NASA’s Optical Telescope Element manager at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.

     The PMBSS was verified through this static testing by mounting it to a structure that evaluated its load support capabilities, and verified it can withstand the forces from its launch atop an Ariane 5 rocket, which is currently scheduled for 2018. This serves as the final test needed before the start of the PMBSS integration with other components of the telescope.

     Webb’s PMBSS will support the telescope’s primary scientific instruments and the primary mirror, comprised of 18 beryllium mirror segments that work in conjunction to form a 21-foot-diameter optical surface. Flawless precision is required for this primary mirror to perform in space, and gather the starlight that astronomers working with JWST will analyze in the future.

     JWST will be subjected to extreme temperatures in space ranging from -406 to -343 degrees Fahrenheit. To ensure that the primary mirror segments are kept relatively in the same position, the materials that comprise the PMBSS must not move of flex more than 1/1,000 the diameter of a human hair which is around 38 nanometers.

     The PMBSS structure is built from advanced fabrication and state-of-the-art material, including  lightweight graphite and other composite parts that total more than 10,000 assembled pieces. All combined this assembly weighs 2,180 pounds and is strong enough to support 7,300 pounds of mission payload and scientific instruments.

     “This is the largest, most complex cryogenically stable structure humans have ever built,” said Scott Texter, Webb optical telescope element manager, Northrop Grumman. “Completion of the static testing verifies that it can hold the weight it is designed to hold. Now the structural backbone of the observatory is officially verified and ready for integration.”

     Next in line for JWST will be the creation of the overall Optical Telescope Element (OTE) when this support structure is integrated with its deployment elements and installation with its array of mirrors at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Cryogenic testing of the PMBSS with continue at Goddard once the integration of the primary mirror is completed, which will follow up on the extreme cryogenic thermal evaluations that occurred at NASA’s Marshall Space Flight Center last fall.

     Despite setbacks, near cancellation, budgetary concerns and more than a decade of delays, JWST continues to strive for realization. If everything continues as planned, this next-generation observatory will give insight to distant planets, shed light on scientific mysteries and answer questions about the creation of the universe. This joint project between NASA, the European Space Agency (ESA), and Canadian Space Agency (CSA), is designed to provide thousands of astronomers around the world infrared images to aid in future scientific discoveries.

By James Tutten

(Above photo provided by Northrop Grumman)

(Published at www.spaceflightinsider.com on July 9, 2014.)

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