ROOM
24
Special Report
that can go out far into interplanetary space.
As they interact with the Sun’s magnetic field,
the electron beams generate bursts of radio
frequency signals. They are in a frequency range
(less than 15 MHz) that can’t be seen by radio
telescopes on Earth because they are blocked
by our ionosphere. If we could position a radio
telescope up at geostationary orbit (GEO) or
higher, well above the ionosphere, we could
observe and characterise these short-lived
phenomena, a long-standing goal of the solar
physics community.
With Prof Justin Kasper of the University of
Michigan leading the science, and the Space
Dynamics Lab at Utah State designing the
spacecraft, JPL has proposed the SunRISE
mission to NASA. The SunRISE mission concept
is a constellation of six cubesats, each carrying
a radio frequency receiver, deployed just above
GEO orbit. Signals collected by individual
cubesats are combined to form a ‘synthetic
aperture’ in space, a tried-and-tested technique
that allows multiple radio telescopes to
coordinate to resolve signal sources such as
Coronal Mass Ejections with improved resolution.
Developing technologies
If you’re trying to do big science with small
spacecraft, there is no point in arriving at an
exotic destination in the solar system if you can’t
make useful, science-grade measurements. If
it’s an object we haven’t visited before a simple
optical snapshot may add to our scientific
knowledge, but if we’ve been a few times already
we need more capable sensors.
Not all the instruments we need for deep
space exploration can be miniaturised to
fit within the constraints of a cubesat or
Exploring ocean worlds
Europa is one of the ‘ocean worlds’ in our
solar system that planetary scientists believe
may be a suitable place for life to have arisen
independently. JPL’s Europa Clipper project is
planning to head there in 2022 and has supported
the maturation of cubesat concepts that have
the potential to enhance the science achieved
at Europa. These cubesats would be carried to
Jupiter by the host spacecraft and then released
on approach to execute their assigned mission.
In this hitch-hiker architecture, the cubesats
can get much nearer to the surface of Europa
than the primary spacecraft, enabling unique
science observations.
One concept proposed by the University
of Michigan would use multi-frequency
magnetic induction sounding from a compact
magnetometer to characterise the subsurface
ocean of Europa. Another proposed by Robert
Ebert of the Southwest Research Institute is
the JUpiter MagnetosPheric boundary ExploreR
(JUMPER), a SmallSat to study Jupiter’s magnetic
field, including its interaction with the solar wind.
Observing our Sun
The Sun is a massive, roiling, dynamic object
at the centre of our solar system. Energetic
solar flares, known as Coronal Mass Ejections,
shoot out beams of high-energy electrons
The SunRISE cubesat
constellation observing
Coronal Mass Ejections
from the Sun.
NASA/JPL
The Moon is so tantalizingly close that you would
think we’d understand all there is to know about
our celestial companion - but our lunar scientists
would say you’re wrong
