Gravity and Extreme Magnetism SMEX
Encyclopedia
The Gravity and Extreme Magnetism SMEX (GEMS) mission is a planned space observatory. The main scientific goal of GEMS is to be the first mission to systematically measure the polarization of cosmic X-Ray
sources. GEMS will provide data to help scientists study the shape of space that has been distorted by a spinning Black hole
's gravity and the structure and effects of the magnetic fields around Neutron stars
.
GEMS is a project managed by the National Aeronautics and Space Administration NASA
, the United States space agency, at the Goddard Space Flight Center
. The project is an Astrophysics
program reporting to NASA's Science Mission Directorate
(SMD) in Washington, D.C.
.
Current plans call for the spacecraft to be launched on in July 2014 on a nine month mission. A possible science enhancement option would extend the mission with a 15 month guest observer phase.
will be designed to indirectly measure the regions of distorted space around spinning black hole
s through a measurement of the polarization of X-rays emitted. It will thereby probe the structure and effects of the magnetic field
around magnetar
s and dead stars with magnetic fields trillions of times stronger than Earth's.
GEMS could reveal:
Current missions cannot do this because the required Angular resolution
is limited and magnetic fields are invisible.
The detector in GEMS will be a small chamber filled with gas. When an X-ray is absorbed in the gas, an electron carries off most of the energy, and starts out in a direction related to the polarization direction of the X-ray. This electron loses energy by ionizing the gas; the instrument measures the direction of the ionization track, and thereby the polarization of the X-ray. The GEMS detector readout will employ a time projection chamber to image the track. The GEMS instrument is about 100 times more sensitive than previous X-ray polarization experiments.
Mission costs will be capped at US$105 million (in Fiscal Year 2008 dollars), excluding the launch vehicle.
GEMS was one of six Small Explorer missions selected in May 2008 for the NASA
Small Explorer (SMEX) Program Phase A study. In June 2009, GEMS was chosen to be the second of these missions to go forward into Phase B, starting in October 2010 for a launch in April 2014.
The project completed and successfully passed the Systems Requirements Review (SRR) Design review (US Government) in December 2010.
is Dr Jean H. Swank
, of NASA's Goddard Space Flight Center
, Greenbelt, Maryland
.
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X-ray astronomy
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and...
sources. GEMS will provide data to help scientists study the shape of space that has been distorted by a spinning Black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
's gravity and the structure and effects of the magnetic fields around Neutron stars
Neutron star
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
.
GEMS is a project managed by the National Aeronautics and Space Administration NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
, the United States space agency, at the Goddard Space Flight Center
Goddard Space Flight Center
The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...
. The project is an Astrophysics
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
program reporting to NASA's Science Mission Directorate
Science Mission Directorate
The Science Mission Directorate of the National Aeronautics and Space Administration engages the United States’ science community, sponsors scientific research, and develops and deploys satellites and probes in collaboration with NASA’s partners around the world to answer fundamental questions...
(SMD) in Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
.
Current plans call for the spacecraft to be launched on in July 2014 on a nine month mission. A possible science enhancement option would extend the mission with a 15 month guest observer phase.
Mission
The GEMS X-ray telescopeX-ray telescope
An X-ray telescope is a telescope that is designed to observe remote objects in the X-ray spectrum. In order to get above the Earth's atmosphere, which is opaque to X-rays, X-ray telescopes must be mounted on high altitude rockets or artificial satellites.-Optical design:X-ray telescopes can use...
will be designed to indirectly measure the regions of distorted space around spinning black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
s through a measurement of the polarization of X-rays emitted. It will thereby probe the structure and effects of the magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
around magnetar
Magnetar
A magnetar is a type of neutron star with an extremely powerful magnetic field, the decay of which powers the emission of copious high-energy electromagnetic radiation, particularly X-rays and gamma rays...
s and dead stars with magnetic fields trillions of times stronger than Earth's.
GEMS could reveal:
- How spinning black holes affect space-time and matter as they are drawn in and compressed by strong gravitational fields.
- What happens in the super strong magnetic fields near pulsars and magnetars.
- How cosmic rays are accelerated by shocks in supernova remnants.
Current missions cannot do this because the required Angular resolution
Angular resolution
Angular resolution, or spatial resolution, describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object...
is limited and magnetic fields are invisible.
The detector in GEMS will be a small chamber filled with gas. When an X-ray is absorbed in the gas, an electron carries off most of the energy, and starts out in a direction related to the polarization direction of the X-ray. This electron loses energy by ionizing the gas; the instrument measures the direction of the ionization track, and thereby the polarization of the X-ray. The GEMS detector readout will employ a time projection chamber to image the track. The GEMS instrument is about 100 times more sensitive than previous X-ray polarization experiments.
Mission costs will be capped at US$105 million (in Fiscal Year 2008 dollars), excluding the launch vehicle.
Project Status
The GEMS project is currently in the definition phase (Phase B). Phase B focuses on requirements definition to design and develop the technical specifications for the spacecraft and instrument.GEMS was one of six Small Explorer missions selected in May 2008 for the NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
Small Explorer (SMEX) Program Phase A study. In June 2009, GEMS was chosen to be the second of these missions to go forward into Phase B, starting in October 2010 for a launch in April 2014.
The project completed and successfully passed the Systems Requirements Review (SRR) Design review (US Government) in December 2010.
Project and Science Team
The GEMS Principal InvestigatorPrincipal investigator
A principal investigator is the lead scientist or engineer for a particular well-defined science project, such as a laboratory study or clinical trial....
is Dr Jean H. Swank
Jean Swank
Jean H. Swank is an astrophysicist, having received her PhD degree from the California Institute of Technology in 1967 under the supervision of Steve Frautschi. Swank was named as the project scientist for NASA's Rossi X-ray Timing Explorer mission, and Principal Investigator for the Gravity and...
, of NASA's Goddard Space Flight Center
Goddard Space Flight Center
The Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...
, Greenbelt, Maryland
Greenbelt, Maryland
Greenbelt is a city in Prince George's County, Maryland, United States. Contained within today's City of Greenbelt is the historic planned community now known locally as "Old Greenbelt" and designated as the Greenbelt Historic District...
.
Project Team
- GSFC will be responsible for the GEMS instrument, system engineering, spacecraft contract, and the overall program management.
- Ames Research Center will provide Co-Investigators and perform the Education and Public Outreach(EPO)support.
- The satellite will be built by Orbital Sciences using its LEOStar-2 TM spacecraft bus design, and will also conduct mission operations, under a US$40 million contract.
- Alliant TechsystemsAlliant TechsystemsAlliant Techsystems Inc., most commonly known by its ticker symbol, ', is one of the largest aerospace and defense companies in the United States with more than 18,000 employees in 22 states, Puerto Rico and internationally, and 2010 revenues in excess of an estimated...
(ATK) wwill build a deployable boom to place the X-ray mirrors at the proper distance from the detectors or polarimeters. - The University of IowaUniversity of IowaThe University of Iowa is a public state-supported research university located in Iowa City, Iowa, United States. It is the oldest public university in the state. The university is organized into eleven colleges granting undergraduate, graduate, and professional degrees...
will provide instrument calibration assistance and will have students prepare a small instrument that could be part of the mission.
Co-Investigators
- NASA Goddard Space Flight CenterGoddard Space Flight CenterThe Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...
- NASA Ames Research Center
- University of IowaUniversity of IowaThe University of Iowa is a public state-supported research university located in Iowa City, Iowa, United States. It is the oldest public university in the state. The university is organized into eleven colleges granting undergraduate, graduate, and professional degrees...
- Massachusetts Institute of Technology
Science Collaborators
Other GEMS collaborators are from universities include:- Johns Hopkins UniversityJohns Hopkins UniversityThe Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...
- Cornell UniversityCornell UniversityCornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...
- Rice UniversityRice UniversityWilliam Marsh Rice University, commonly referred to as Rice University or Rice, is a private research university located on a heavily wooded campus in Houston, Texas, United States...
- University of OuluUniversity of OuluThe University of Oulu is one of the largest universities in Finland, located in the city of Oulu. It was founded on July 8, 1958. The university has around 16,000 students and 3,000 staff...
(FinlandFinlandFinland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
) - North Carolina State UniversityNorth Carolina State UniversityNorth Carolina State University at Raleigh is a public, coeducational, extensive research university located in Raleigh, North Carolina, United States. Commonly known as NC State, the university is part of the University of North Carolina system and is a land, sea, and space grant institution...
- Washington University
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