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By Rick Smith<\/em><\/p>\n \u201cThe art of aerospace engineering is a matter of seeing around corners,\u201d said NASA thermal analyst Jodi Turk. In the case of NASA\u2019s Chandra X-ray Observatory, marking its 25th anniversary in space this year, some of those corners proved to be as far as 80,000 miles away and a quarter-century in the future.<\/p>\n Turk is part of a dedicated team of engineers, designers, test technicians, and analysts at NASA\u2019s Marshall Space Flight Center in Huntsville, Alabama. Together with partners outside and across the agency, including the Chandra Operations Control Center in Burlington, Massachusetts, they keep the spacecraft flying, enabling Chandra\u2019s ongoing studies of black holes, supernovae, dark matter, and more \u2013 and deepening our understanding of the origin and evolution of the cosmos.<\/p>\n \u201cEverything Chandra has shown us over the last 25 years \u2013 the formation of galaxies and super star clusters, the behavior and evolution of supermassive black holes, proof of dark matter and gravitational wave events, the viability of habitable exoplanets \u2013 has been fascinating,\u201d said retired NASA astrophysicist Martin Weisskopf, who led Chandra scientific development at Marshall beginning in the late 1970s. \u201cChandra has opened new windows in astrophysics that we\u2019d hardly begun to imagine in the years prior to launch.\u201d<\/p>\n Following extensive development and testing by a contract team managed and led by Marshall, Chandra was lifted to space aboard the space shuttle Columbia on July 23, 1999. Marshall has continued to manage the program for NASA ever since.<\/p>\n \u201cHow much technology from 1999 is still in use today?\u201d said Chandra researcher Douglas Swartz. \u201cWe don\u2019t use the same camera equipment, computers, or phones from that era. But one technological success \u2013 Chandra \u2013 is still going strong, and still so powerful that it can read a stop sign from 12 miles away.\u201d<\/p>\n That lasting value is no accident. During early concept development, Chandra \u2013 known prior to launch as the Advanced X-ray Astrophysics Facility \u2013 was intended to be a 15-year, serviceable mission like that of NASA\u2019s Hubble Space Telescope, enabling periodic upgrades by visiting astronauts.<\/p>\n But in the early 1990s, as NASA laid plans to build the International Space Station in orbit, the new X-ray observatory\u2019s budget was revised. A new, elliptical orbit would carry Chandra a third of the way to the Moon, or roughly 80,000 miles from Earth at apogee. That meant a shorter mission life \u2013 five years \u2013 and no periodic servicing.<\/p>\n The engineering design team at Marshall, its contractors, and the mission support team at the Smithsonian Astrophysical Observatory revised their plan, minimizing the impact to Chandra\u2019s science. In doing so, they enabled a long-running science mission so successful that it would capture the imagination of the nation and lead NASA to extend its duration past that initial five-year period.<\/p>\n \u201cThere was a lot of excitement and a lot of challenges \u2013 but we met them and conquered them,\u201d said Marshall project engineer David Hood, who joined the Chandra development effort in 1988.<\/p>\n \u201cThe field of high-powered X-ray astronomy was still so relatively young, it wasn\u2019t just a matter of building a revolutionary observatory,\u201d Weisskopf said. \u201cFirst, we had to build the tools necessary to test, analyze, and refine the hardware.\u201d<\/p>\n Marshall renovated and expanded its X-ray Calibration Facility \u2013 now known as the X-ray & Cryogenic Facility \u2013 to calibrate Chandra\u2019s instruments and conduct space-like environment testing of sensitive hardware. That work would, years later, pave the way for Marshall testing of advanced mirror optics for NASA\u2019s James Webb Space Telescope.<\/p>\n \u201cMarshall has a proven history of designing for long-term excellence and extending our lifespan margins,\u201d Turk said. \u201cOur missions often tend to last well past their end date.\u201d<\/p>\n Chandra is a case in point. The team has automated some of Chandra\u2019s operations for efficiency. They also closely monitor key elements of the spacecraft, such as its thermal protection system, which have degraded as anticipated over time, due to the punishing effects of the space environment.<\/p>\n \u201cChandra\u2019s still a workhorse, but one that needs gentler handling,\u201d Turk said. The team met that challenge by meticulously modeling and tracking Chandra\u2019s position and behavior in orbit and paying close attention to radiation, changes in momentum, and other obstacles. They have also employed creative approaches, making use of data from sensors on the spacecraft in new ways.<\/p>\n Acting project manager Andrew Schnell, who leads the Chandra team at Marshall, said the mission\u2019s length means the spacecraft is now overseen by numerous \u201cthird-generation engineers\u201d such as Turk. He said they\u2019re just as dedicated and driven as their senior counterparts, who helped deliver Chandra to launch 25 years ago.<\/p>\n The work also provides a one-of-a-kind teaching opportunity, Turk said. \u201cTroubleshooting Chandra has taught us how to find alternate solutions for everything from an interrupted sensor reading to aging thermocouples, helping us more accurately diagnose issues with other flight hardware and informing design and planning for future missions,\u201d she said.<\/p>\n Well-informed, practically trained engineers and scientists are foundational to productive teams, Hood said \u2013 a fact so crucial to Chandra\u2019s success that its project leads and support engineers documented the experience in a paper titled, \u201cLessons We Learned Designing and Building the Chandra Telescope.\u201d<\/p>\n \u201cFormer program manager Fred Wojtalik said it best: \u2018Teams win,\u2019\u201d Hood said. \u201cThe most important person on any team is the person doing their work to the best of their ability, with enthusiasm and pride. That\u2019s why I\u2019m confident Chandra\u2019s still got some good years ahead of her. Because that foundation has never changed.\u201d<\/p>\n As Chandra turns the corner on its silver anniversary, the team on the ground is ready for whatever fresh challenge comes next.<\/p>\n Learn more about the Chandra X-ray Observatory and its mission here:<\/p>\n \n \n