SAMPEX is the first of SMEX'es (SMall EXplorers). SAMPEX was launched in July 1992 from Western Test Range (Lompoc,CA) at 1419 UT on July 3, 1992. SAMPEX orbits at an altitude 520 by 670 Km and 82 degrees inclination and carries four instruments on board. SAMPEX measures energetic electrons as well as ion composition of particle populations from ~0.4 MeV/nucleon to hundreds of MeV/nucleon from a zenith-oriented satellite in a near polar orbit. The Payload combines some of the most sensitive particle sensors ever flown in space.
Figure to the left shows Solar sunspot numbers and spacecraft timelines
through the next solar maximum. This fleet of spacecraft provides a unique
opportunity to observe the upcoming solar maximum activity with unprecedented
capabilities. SAMPEX will be a crucial element in this picture, covering the
last leg of the energy-momentum flow from the sun into the earth's atmosphere
and magnetosphere, a vital part of the Sun-Earth Connection theme and the
upcoming LWS (Living With a Star) program.
SAMPEX Studies the energy,composition, and charge states of particles from
supernova explosions in the distant reaches of the galaxy, from the heart of
solar flares, and from the depths of nearby interstellar space. It also
monitors closely the magnetospheric particle populations which plunge
occasionally into the middle atmosphere of the Earth, thereby ionizing neutral
gases and altering the atmospheric chemistry. A key part of SAMPEX is to use the
magnetic field of the earth as an essential component of the measurement
strategy. The Earth's field is used as a giant magnetic spectrometer to
separate different energies and charge states of particles as SAMPEX executes
its near polar orbit.
Nearly five years after its launch into the current minimum of the solar cycle,
SAMPEX has carried out a wide range of observations and discoveries concerning
solar, heliospheric, and magnetospheric energetic particles seen from its
unique vantage point in a nearly polar, low Earth orbit. Since almost all of
the processes we are studying are driven or heavily influenced by the solar
activity cycle, we have the opportunity to fully characterize the solar
cycle dependence of a wide range of processes central to the goals of the NASA
Office of Space Science's Sun-Earth Connections (SEC) theme. Over the next
several years as the solar activity ramps up to its 11-year maximum, SAMPEX
investigations will:
SAMPEX investigations are addressing a very broad range of questions. We have
carried out and reported to the scientific community major findings
addressing the solar, anomalous, and magnetospheric particles for which the
mission is named.
Since the Sun's activity cycle has profound influences on most NASA Sun-Earth
Connection (SEC) questions, it is essential to carry out observations during
both solar quiet and solar active periods if a scientific understanding of the
processes is to be achieved.
Most of these investigations can only be carried out using SAMPEX's unique
orbit and highly sensitive detectors, and cannot be accomplished with other
operating or planned spacecraft.
survey the acceleration of relativistic
electrons,measure their impact on the upper atmosphere, and determine their
influence on atmospheric chemistry not only for solar minimum conditions but
also for the much more complex solar active periods
obtain samples of solar material from dozens of
flares, compared with the handful observed during the declining phase of the
solar cycle
measure the anomalous component isotopic
composition, trapping lifetime, and disappearance near solar maximum
serve as a unique link in the chain of
observatories put in place by NASA and its international partners
to study space weather during the upcoming solar maximum.
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