One of NASA's smallest spacecraft, scheduled for launch March 1, will tackle a very big cosmic question: What is the history of star-formation in the Universe?
NASA's first new spacecraft in the Origins Program, the Wide-Field Infrared Explorer (WIRE), is scheduled for launch at 10 p.m. EST on March 1 from Vandenberg Air Force Base (AFB), CA.
The four-month mission will help understand how and when galaxies formed, and the subsequent history of star-formation in the Universe. Answers to these questions will shed a strong light on the very nature of the Universe.
"In many ways this inaugural mission of NASA's Origins Program, which will study the birth of star-forming galaxies, will move us towards our ultimate goals," said Dr. Harley Thronson, acting director of the Astronomical Search for Origins science theme at NASA Headquarters, Washington, DC. "One of the Origins Program's long-term goals is to understand the formation of not only the Universe, but the galaxies and stars we see everywhere in the cosmos. WIRE will provide us with a wealth of information, which will get us closer to understanding how the Universe could reach the point of forming Sun-like stars and Earth-like planets. And, WIRE will do that at a very modest cost."
"Our science team will measure how densely filled the Universe has been with star-forming galaxies during its history, and how quickly those galaxies have been forming stars," said WIRE Principal Investigator Perry Hacking of Vanguard Research, Inc., Fairfax, VA; NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA; and a professor at El Camino College, Torrance, CA. "WIRE also will conduct a search for powerful, dusty quasars in the very early Universe, shortly after the Big Bang. If found in significant numbers, these quasars will carry strong implications about the age and structure of our Universe."
Additional WIRE science investigations will include detailed inventories of some star-forming regions in our own Milky Way galaxy; searches for small, substellar objects called 'methane dwarfs,' which are essentially more massive versions of the planet Jupiter; searches of nearby stars for leftover debris from planet formation; a more complete inventory of the asteroid belt, and much more.
The 561-pound (254-kg) spacecraft will be launched from Vandenberg AFB on a Pegasus-XL launch vehicle built by Orbital Sciences Corporation. The launch vehicle is a three-stage, solid-propellant booster system carried aloft by a Lockheed L-1011 jet aircraft. The system will be released when the aircraft reaches an altitude of about 40,000 feet (12,200 meters).
The WIRE instrument consists of a 12.5-inch (30-centimeter) aperture Cassegrain telescope with no moving parts and a field of view about the size of the full moon. The telescope is enclosed within a two-stage, state-of-the-art, solid-hydrogen cryostat, which will keep the instrument's mirrors cooled to below -436 F. The cryostat is designed like a thermos bottle, using a vacuum space between layers of insulation, and uses the sublimation (the direct transition from a solid to a gas) of frozen hydrogen to cool the telescope. The telescope must be cold so that its own heat emission doesn't overwhelm the light that it is trying to detect from space.
The WIRE observatory will be inserted into an orbit with an altitude of 340 miles (540 km) above the Earth, and will orbit the Earth every 90 minutes. The observed data will be stored in the spacecraft memory and sent to ground stations at Poker Flat, AL, and NASA's Wallops Flight Facility, VA. From there the data will be sent to the spacecraft control center at NASA's Goddard Space Flight Center, Greenbelt, MD, and then on to the science operations center at the Infrared Processing and Analysis Center (IPAC), California Institute of Technology, Pasadena, for data calibration and analysis. The WIRE teaming partner is Space Dynamics Laboratory at Utah State University, Logan, UT.
WIRE is the last of an initial series of Small Explorers (SMEX) that have been designed and built at Goddard. The Small Explorer office has provided the mission, spacecraft, and ground system engineering and the principal investigator has provided the scientific instrumentation for these missions.
The WIRE observatory was integrated into a three-axis-stabilized spacecraft designed, built, and tested by the SMEX Project Team at Goddard. The telescope assembly is provided to Goddard by JPL. After an initial checkout period of thirty days on orbit, scientific operations will be coordinated by JPL through the science operations center at IPAC.
The SMEX program provides frequent flight opportunities for highly focused, relatively inexpensive and small space science missions. Each mission is cost-capped for design, development, and operations through the first 30 days in orbit. Using modern technology and management techniques, the program is dedicated to the forty-year Explorer Program tradition of service to the space science community.
"The Small Explorer program has produced remarkable results," said Jim Watzin, Project Manager for SMEX. The SMEX program already has four spacecraft (SAMPEX, FAST, SWAS and TRACE) successfully operating on-orbit. "All were completed on schedule and within or below the program cost constraints," he said. "All missions differed dramatically from each other in form, function, and scope. WIRE will be the fifth and final mission developed in this manner." Future SMEX missions are to be built at the institution chosen by the principal investigator.
The WIRE Project website is located at: http://sunland.gsfc.nasa.gov/smex/wire/
The WIRE science website is located at: http://www.ipac.caltech.edu/wire/
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