NUSOL MISSION
Measurement of solar neutrinos is important for scientific studies aimed at understanding
the interior
of the Sun. While there have been many Earth-based experiments measuring solar neutrinos,
one has never been done in space. Around 2015, Dr. Nick Solomey of WSU Physics envisioned flying
a small-sized neutrino detector close to the Sun. Since then, there has been an increasing
interest within NASA to conduct scientific studies in space using a neutrino detector.
Formally referred to as the NuSol, the mission idea is centered around the fact that
high solar neutrino flux close to the Sun only makes a small-sized detector necessary
for the experiments. Detectors used for Earth-based studies are typically very large,
of the order of 10,000 kg, and a detector flying close to the Sun (Parker Solar Probe
distances) will allow for two orders of magnitude reduction in the detector size.
In addition, a space-based study has additional advantages. For instance, Earth-based
detectors lie deep underground and the neutrinos interacting with them have many sources:
Sun, cosmic rays, and terrestrial nuclear experiments; hence, any Earth-based study
needs to be able to separate the effect of cosmic rays and geoneutrino sources in
order to be able to relate the experimental results to processes happening at the
Sun. In contrast, a detector approaching the Sun on a spacecraft will see a decreased
flux of cosmic rays and geoneutrino sources are absent; hence, the experimental results
will be directly correlated to the solar processes. Furthermore, there are unique
scientific phenomenon related to the transition of coherence of solar neutrinos that
happen near the Sun, and can never be observed by an Earth-based study. To this end,
the NuSol mission study, supported by the NASA Innovative Advanced Concepts (NIAC)
program, investigated the feasibility of a scientific demonstration mission for in-space
solar neutrino detection; it was observed that flying a detector on a probe flying
the trajectories similar to that of Parker Solar Probe would be a practical solution
that allows for sufficient scientific studies and yet keep costs reasonable owing
to reuse of spacecraft bus components that have flight heritage from
Parker Solar Probe mission.
SNAPPY MISSION
Recognizing the fact that a solar neutrino detector has never flown in space, the
Phase-III part of
the NIAC project focuses on the development of a CubeSat to validate the operation
of a prototype
detector in near-Earth space. It is important to note here that in near-Earth environment,
a smallsized
CubeSat-class detector will not be able to detect any solar neutrino. However, the
CubeSat
mission provides opportunities to validate the detector with respect to its interaction
with cosmic
rays (background). The 3U CubeSat is anticipated to be launched in 2025 into a sun-synchronous
low-Earth orbit and will gather scientific data primarily over the poles (both North
and South poles).
PUBLICATIONS
Preliminary Mission Design for Proposed NuSol Probe
Authors: K. Messick, A. Dutta, H. Meyer, M. Christl, N. Solomey
Abstract: A solar neutrino detector has never flown in space. NuSol is a proposed mission
to fly a solar neutrino detector close to the Sun in order to conduct unique sci-
ence objectives that cannot be realized by detectors on Earth. The paper presents
a
preliminary trajectory design for the NuSol mission in order to accomplish the sci-
ence goals, taking into account specified mission cost constraints, a given launch
window, and an overall mission duration. Numerical simulations are presented to
compare different mission scenarios and to identify a trajectory design that realizes
the science goals of the mission.
Preliminary mission design for proposed NuSol probe
Author: K. Messick
Abstract: A solar neutrino detector has never flown in space. NuSol is a proposed mission
to fly a solar neutrino detector close to the Sun in order to conduct unique science
experiments that cannot be realized by detectors on Earth. This research presents
a preliminary trajectory design for the NuSol mission in order to accomplish the science
goals, taking into account operational and specified mission cost constraints, given
launch window, and an overall mission duration. To quickly check through a diverse
design space of possible mission solutions, a mission design algorithm was developed
in MATLAB. The mission design procedure used in this thesis is based on the standard
patched-conics methodology to break the mission into a sequence of two-body problems,
starting with a hyperbolic Earth escape trajectory and followed by elliptic heliocentric
orbits yielding multiple planetary arrival phases. Minimization of the final perihelion
is done by utilizing multiple consecutive gravity assist (GA) maneuvers to reshape
the initial trajectory after a launch and departure from Earth. As launch costs prove
to be a substantial share of the overall mission cost, the study is restricted to
initial launch energies which equal 100 km2/s or less. This study provides insight on the closest reachable distance to the Sun
when given a specified wet mass and launch vehicle. The work also addresses many issues
in trade offs that arise in multi-GA maneuver mission design studies. These issues
include mass trade
offs at launch as well as during the heliocentric transfer when comparing ballistic
and powered GA maneuvers. One of the greatest challenges the research works to overcome
is the computational time and resources that are required when analyzing a vast mission
design space. The results for the study indicate that a currently available launch
vehicle can deploy the 1,400 kg spacecraft housing the neutrino detector in a Earth-Venus
transfer orbit, which will eventually reach below 20 Solar Radii within the stipulated
time of 5 years.