Launching Rockets from the Top of the World 🚀

Over the next 14 months, our scientists will join a group of
international researchers to explore a special region — Earth’s northern polar
cusp, one of just two places on our planet where particles from the Sun have
direct access to our atmosphere.

image

Earth is surrounded by a giant magnetic bubble known as a magnetosphere,
which protects our planet from the hot, electrically charged stream of
particles from the Sun known as the solar wind. The northern and southern polar
cusps are two holes in this protection — here, Earth’s magnetic field lines
funnel the solar wind downwards, concentrating its energy before injecting it
into Earth’s atmosphere, where it mixes and collides with particles of Earthly
origin.

image

The cusp is the only place where dayside auroras
are found — a special version of northern and southern lights, visible when the
Sun is out and formed by a different process than the more familiar nighttime
aurora. That’s what makes this region so interesting for scientists to study: The
more we learn about auroras, the more we understand about the fundamental
processes that drive near-Earth space — including those processes that disrupt
our technology and endanger our astronauts.

image

Photo credit: Violaene
Kaeser

The teams working on the Grand
Challenge Initiative — Cusp
will fly sounding rockets from two
Norwegian rocket ranges that fall under the cusp for a short time each day. Sounding
rockets
are sub-orbital rockets that shoot up into space for a few
minutes before falling back to Earth, giving them access to Earth’s atmosphere
between 30 and 800 miles above the surface. Cheaper and faster to develop than
large satellite missions, sounding rockets often carry the latest scientific
instruments on their first-ever flights, allowing for unmatched speed in the
turnaround from design to implementation.

image

Each sounding rocket mission will study a different aspect
of Earth’s upper atmosphere and its connection to the Sun and particles in
space. Here’s a look at the nine missions coming up.

1. VISIONS-2 (Visualizing
Ion Outflow via Neutral Atom Sensing-2) — December 2018

The cusp isn’t just the inroad into our atmosphere — it’s a
two-way street. Counteracting the influx of particles from the Sun is a process
called atmospheric escape, in which Earthly particles acquire enough energy to
escape into space. Of all
the particles that escape Earth’s atmosphere, there’s one that presents a
particular mystery: oxygen.

At 16 times the mass of hydrogen, oxygen should be too heavy
to escape Earth’s gravity. But scientists have found singly ionized oxygen in
near-Earth space, which suggests that it came from Earth. The two VISIONS-2 rockets,
led by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will create
maps of the oxygen outflow in the cusp, tracking where these heavy ions are and
how they’re moving to provide a hint at how they escape.

2. TRICE-2 (Twin
Rockets to Investigate Cusp Electrodynamics 2) — December 2018

If the cusp is like a funnel, then magnetic reconnection is
what turns on the faucet. When the solar wind collides with Earth’s magnetic
field, magnetic reconnection breaks open the previously closed magnetic field
lines, allowing some solar wind particles to stream into Earth’s atmosphere
through the cusp.

But researchers have noticed that the stream of particles
coming in isn’t smooth: instead, it has abrupt breaks in it. Is magnetic
reconnection turning on and off? Or is the solar wind shooting in from
different locations? TRICE-2, led by the University of Iowa in Iowa City, will
fly two separate rockets through a single magnetic field line in the cusp, to
help distinguish these possibilities. If reconnection sputters on and off over
time, then the two rockets should get quite different measurements, like noting
how it feels to run your finger back and forth under a faucet that is being
turned on and off. If instead reconnection happens consistently in multiple
locations — like having ten different faucets, all running constantly — then the
two rockets should have similar measurements whenever they pass through the
same locations.

image

Magnetic reconnection is a process by which magnetic field
lines explosively realign  

3. CAPER-2 (Cusp
Alfvén and Plasma Electrodynamics Rocket) — January 2019

The CAPER-2 rocket, led by Dartmouth College in Hanover, New
Hampshire, will examine how fast-moving electrons — particles that can trigger
aurora — get up to such high speeds. The team will zero in on the role that
Alfvén waves, a special kind of low-frequency wave that oscillates along
magnetic field lines, play in accelerating auroral electrons.

image

An illustration of rippling Alfvén waves

4. G-CHASER (Grand
Challenge Student Rocket) — January 2019

G-CHASER is made up entirely of student researchers from universities
in the United States, Norway and Japan, many of whom are flying their
experiments for the first time. The mission, led by the Colorado Space
Grant Consortium at the University of Colorado Boulder,
is a collaboration between seven different student-led missions,
providing a unique opportunity for students to design, test and ultimately fly
their experiment from start to finish. The students involved in the mission —
mostly undergraduates but including some graduate teams — are responsible for
all aspects of the mission, from developing the initial idea, to securing the
funding, to making sure it passes all the tests before flight.

5 & 6. AZURE (Auroral
Zone Upwelling Rocket Experiment) and CHI
(Cusp Heating Investigation) — April & November/December 2019

When the aurora shine, they don’t just emit light — they
also release thermal and kinetic energy into the atmosphere. Some of this
energy escapes back into space, but some of it stays with us. Which way this
balance tips depends, in part, on the winds in the cusp. AZURE, led by Clemson
University in South Carolina, will measure the vertical winds that swish energy
and particles around within the auroral oval, the larger ring around the pole
where the aurora are most common.

Later that year, the same team will launch the CHI mission, using a
methodology similar to AZURE to measure the flow of charged and neutral gases
inside the cusp. The goal is to better understand how particles, flowing in
horizontal and vertical directions, interact with each other to produce heating
and acceleration.

7. C-REX-2 (Cusp-Region
Experiment) — November 2019

The cusp is a place where strange physics happens, producing
some anomalies in the physical structure of the atmosphere that can make our
technology go haywire. For satellites that pass through the cusp, density
increases act like potholes, shaking up their orbits. Scientists don’t
currently understand what causes these density increases, but they have some
clues. C-REX-2, led by the University of Alaska Fairbanks, aims to figure out
which variables — wind, temperature or ion velocity — are responsible.

8. ICI-5
(Investigation of Cusp Irregularities-5) — December 2019

Recent research has uncovered mysterious hot patches of
turbulent plasma inside the auroral region that rain energetic particles
towards Earth. GPS signals become garbled as they pass through these turbulent
plasma patches, affecting so many of today’s technologies that depend on them. ICI-5,
led by the University of Oslo, will launch into the cusp to take measurements
from inside these hot patches. To measure their structure as several scales,
the rocket will eject 12 daughter payloads in concentric squares which will
achieve a variety of different separations.

image

9. JAXA’s SS-520-3
mission
— January 2020

Exploring the phenomenon of atmospheric escape, the Japan
Aerospace Exploration Agency’s SS-520-3 mission will fly 500 miles high over
the cusp to take measurements of the electrostatic waves that heat ions up and
get them moving fast enough to escape Earth.

For updates on the Grand Challenge Initiative and other
sounding rocket flights, visit nasa.gov/soundingrockets
or follow along with NASA Wallops and NASA heliophysics on Twitter and
Facebook.

@NASA_Wallops | NASA’s Wallops Flight
Facility
| @NASASun | NASA Sun
Science

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com