The Sun ejects vast clouds of ionized gas into space; these clouds are known as coronal mass ejections CMEs. When they engulf Earth, CMEs can disrupt power, navigation, communication and satellite control systems. Despite their importance, scientists don't fully understand the origin or evolution of CMEs, nor their structure or extent in interplanetary space. Both spacecraft look at the Sun itself, and also the region of interplanetary space between the Sun and Earth-like distances 1 Astronomical Unit; 1 AU.
The COR1 optical design is an all-refractive 7-element system. The instrument FOV is is 1. The spectral range is nm. Images are collected at three different linear polarization angles. The occulter is attached to the second optical element in COR1, a doublet field lens.
The final stage consists of two doublets, along with the filter and polarization optics. The stage takes the chromatically aberrated image of the corona, near the occulter, and relays it onto the CCD detector.
The 2k x 2k detector data is summed on-board to 1k x 1k images to produce 7. COR2 Coronagraph2 Imager. The objective is to explore the outer corona R sun in white light and pB with high spatial and temporal resolutions. The optical design of the instrument uses a classical externally occulted Lyot design with an entrance aperture diameter of The spectral range and polarization technique is the same as COR1 to provide a seamless transition between the two regions.
HI Heliospheric Imager. The PI is Richard Harrison. The objective is to extend the concept of traditional externally occulted coronagraphs to a new regime, by observing the heliosphere from the sun to the Earth R sun. The HI is a wide-angle visible-light imaging system for the detection of coronal mass ejection CME events in interplanetary space and, in particular, of events directed towards the Earth.
The HI-2 camera looks further out, from an elongation of The HI-2 objective is set deep within the forward baffle system shadow at a diffraction angle of Table 5: Characteristics of the HI instrument. SEB consists of a control computer, interfaces for the camera and CCD, fine-pointing and jitter control electronics, a housekeeping and data acquisition system, and power conversion. The image processing and compression software employs such compression routines as Rice lossless and a lossy wavelet compression H-compress technique.
The IMPACT investigation science focuses on the magnetic connections to the sun and topology of interplanetary CME-related interplanetary disturbances, and the energetic particles that precede and accompany these disturbances as they move toward Earth.
The SEP package is also a multi-instrument 4 system, but it is more physically integrated, and so included under one heading here. The objective is designed to measure the distribution function of the solar wind core and halo electrons from about 1 eV to several keV, with high spectral and angular resolution over practically the full spherical range.
This capability allows the distinction between these components in detail during both undisturbed periods and the passage of CME generated disturbances, when the interplanetary field rotates far out of the ecliptic plane. The inner plate radius is 3. SWEA compensates for the effects of spacecraft potential on the lowest energy particles by having an outer hemisphere that can be biased according to the plasma density measured by the PLASTIC solar wind ion instrument.
STE is a new instrument that covers electrons in the energy range of about keV with approximately 50 times the sensitivity of previous instruments. These higher energy electrons are frequently accelerated in flares or impulsive flare-like bursts, and they produce solar type III radio bursts as they escape the sun. They provide a unique tracer of the footpoints of CME and normal interplanetary magnetic fields, and allow the measurement of the length of those field lines.
In addition, an electron superhalo is continuously present in the interplanetary medium at those energies. MAG Magnetometer. The fluxgate sensors use a ring core geometry, with magnetic cores consisting of permalloy. The units are compact, low power, and ultra-stable. To optimize sensitivity at the low field values to be found in interplanetary space, the magnetometer dynamic range is divided into 8 ranges that are automatically switched whenever the field being measured exceeds or falls below predetermined levels.
SEP consists of 4 separate instruments that cover the full solar energetic particle energy, flux and composition ranges needed to meet the STEREO science goals. A rare-earth permanent magnet is used to sweep away electrons for ion detection, while a parylene foil transmits electrons but stops protons. It looks in the ecliptic plane along the Parker Spiral magnetic field direction, both forward and backward. The telescope analyzes ions that enter through thin entrance foils and stop in a solid state detector.
A time-of-flight approach for determining the composition utilizes start and stop times obtained from secondary electrons entering a MCP MicroChannel Plate detector system. LET is a special double-fan arrangement of 14 solid-state detectors designed to measure protons and helium ions from about 1. E signatures and ranges together, and penetrating particles will be analyzed.
The FOV covers a The science objective is to measure ions in the energy-per-charge range of 0. The instrument performs three functions in one package: 80 The instrument provides a large IFOV resolved in-ecliptic and in polar angles with measurements taken at high time resolution minutes spanning an ion energy range of 0.
PI: Jean-Louis H. SWAVES can probe a CME from lift-off to Earth by detecting the coronal and interplanetary IP shock of the most powerful CMEs, providing a radial profile through spectral imaging, determining the radial velocity from about 2 R sun from center of sun to Earth, measuring the density of the volume of the heliosphere between the sun and Earth, and measuring important in situ properties of the IP shock, magnetic cloud, and density compression in the fast solar wind stream that follows.
SWAVES uses three mutually orthogonal monopole stacer antenna elements as its prime sensors built by the University of California, Berkeley , each 6 meters in length. The three monopoles are deployed away from the sun so that they remain out of the fields of view of sunward looking instruments. A high input impedance preamplifier is connected to each of the three electric monopoles. This system provides digitized and selectable housekeeping data to monitor the status and health of the various parts of the instrument.
The instrument contains its own internal calibration circuitry. An internal calibration sequence will be invoked about once per day. Space weather data. The STEREO ground system was developed with the intention that the two spacecraft could be operated simultaneously and independently of each other.
This approach minimizes the risk of confusion among operators and other personnel, and it allows for the simultaneous operation of both spacecraft. Operating only the spacecraft bus and engaging a highly automated system, STEREO mission operations are able to use a small team to safely operate two spacecraft simultaneously.
Each spacecraft has a primary and a backup command workstation in the Restricted IONet. Additionally, each spacecraft has a third command workstation, one that is remotely located in a separate building on the APL campus. Additionally, each spacecraft has a dedicated HIL simulator with its own command and telemetry workstation. This configuration allows the developers and testers to access their systems from other laboratory resources, such as employee desktop computers and laptops.
To coordinate mission operations between these teams and return the science data to the mission scientists, a routine flow of data products is necessary. Recovery of spacecraft bus engineering state-of-health telemetry and the performance analysis based on this telemetry are also performed at the MOC. The MOC does not directly verify any instrument commands and does not decommutate or analyze any instrument telemetry aside from currents and temperatures observed from the spacecraft side of the instruments.
Each POC is individually responsible for the health and safety of its instrument. These are the home bases for the instrument POCs, but they are able to operate remotely when necessary, and they also maintain a presence at the MOC. The use of all three DSN antenna facilities—Goldstone, Madrid, and Canberra—is required to determine the elevation component for the navigation of each spacecraft. Nominally, a 3.
First, it is the prime archive of STEREO telemetry and data, and it serves that data to the international science community, and to the general public, through its own website.
Finally, the SSC is the focal point for education and public outreach activities. This operations concept greatly simplifies mission operations and allows for a smaller operations team size and automated, unattended real-time operations for most of the spacecraft contacts. Summary: The STEREO ground system is uniquely divided between the two spacecraft, allowing simultaneous communications with the two spacecraft while minimizing the risk of confusion.
The mission operations tools used for planning, real-time operations, and assessment of spacecraft performance allow for the safe operation of two spacecraft simultaneously. Specifically, separation of command and memory management between the two spacecraft is rigorously maintained.
STEREO mission operations are being accomplished with a minimal number of staff while the science data return is kept well above the minimum requirement for mission success. Baer, J. Eichstedt, D. Strohbehn, M. Martin, S. Kaiser, W. Hill, Teresa M. Hunt Jr. DeForest , R.
Howard , M. Velli , N. Viall , and A. Innes, L. Guo, G. Mason, M. McIntosh, William J. Liu, Janet G. Bale, Charles J. Farrugia, Antoinette B. Howard, J. Moses, D. Wuelser, J. Lemen, T.
Tarbell, C. Wolfson, J. Cannon, B. Carpenter, D. Duncan, G. Gradwohl, S. Meyer, A. Moore, R. Navarro, J. Pearson, G. Rossi, L. Springer , R. Moses, J. Newmark, J. Delaboudiniere, G. Artzner, F. Auchere, M. Bougnet, P. Bouyries, F. Bridou, J. Clotaire, G. Colas, F. Delmotte, A. Jerome, M. Lamare, R. Mercier, M. Mullot, M. Ravet, X. Song, V. Bothmer, W. Gummin, Editors, Vol. Defise, J. Halain, E. Plots of predefined durations of 3 hours [3h], and 1 [1d], 3 [3d], 7 [7d], and 30 days [30d] can be displayed by selecting the appropriate button in the top left.
Choices of pre-defined plots may be selected using the buttons immediately beneath the plot. Along the bottom, a navigation panel depicts the full days of available data.
Following Instruments are on board of each of the two probes: The Sun-Earth Connection Coronal and Heliospheric Investigation SECCHI is a suite of remote-sensing instruments consisting of an extreme ultraviolet imager, two white-light coronagraphs, and a heliospheric imager. These instruments will study the 3-D evolution of coronal mass ejections—the most energetic eruptions on the sun and primary cause of major geomagnetic storms — from their origin at the sun's surface through the corona and interplanetary medium to their eventual impact at Earth.
IMPACT comprises seven instruments including a solar wind electron analyzer, a magnetometer, and an array of particle detectors measuring the energetic ions and electrons accelerated in coronal mass ejection CME shocks and in solar flares. It will supply key diagnostic measurements of mass and charge state composition of heavy ions and will characterize the coronal mass ejection plasma from ambient solar wind plasma. Observation began in early
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