NASA's Parker Solar Probe mission will revolutionize our understanding of the sun.
ENOA, Nev. — A NASA mission to travel closer to the sun than any
previous spacecraft is on its way after a successful launch from Cape
Canaveral Aug. 12.
The United Launch Alliance Delta 4 Heavy carrying NASA’s Parker Solar
Probe mission lifted off from Space Launch Complex 37 at Cape Canaveral
Air Force Station in Florida at 3:31 a.m. Eastern. Controllers scrubbed
a launch attempt the previous day because of technical issues late in
the countdown. The spacecraft separated from its kick stage 43 minutes
after launch.
The 700-kilogram spacecraft required not only a Delta 4 Heavy but
also a Star 48BV kick stage from Northrop Grumman in order to counteract
the Earth’s rotational speed around the sun, allowing it to fall closer
to the sun. The spacecraft will also perform a series of Venus flybys,
starting in early October, to bring it closer to the sun.
Parker Solar Probe will perform its first close approach to the sun in
November, coming within about 24.8 million kilometers. Future flybys
will bring it even closer, eventually coming as close as 6.1 million
kilometers, far closer than any previous spacecraft. During those later
close approaches, the spacecraft will be traveling at up to 695,000
kilometers per hour.
Those close approaches are needed for Parker’s instruments to study
the solar wind and the corona. By taking measurements from within the
corona, scientists hope to better understand how it is heated to
temperatures of millions of degrees. The up-close observations may
reveal new information about solar eruptions and the solar wind.
“We know the magnetic field is the real key. We know this is why
we’re making this daring mission,” said Nicola Fox of the Johns Hopkins
University Applied Physics Laboratory, project science for the mission,
during a pre-launch briefing Aug. 9. “We’re going to go into the
transition from where the magnetic field is dominant to where that
coronal material dominates the magnetic field.”
Development of Parker Solar Probe — previously known as Solar Probe Plus
— dates back a decade, but the idea of sending a spacecraft close to
the sun is far older. Concepts for missions to travel to the sun date
back to the late 1950s, around the time that University of Chicago
physicist Eugene Parker, for whom the mission is named, first proposed
the solar wind.
“For the science community, and some of the engineering community,
it’s really been 60 years,” said Andy Driesman, project manager for the
mission, during the pre-launch briefing. “You can trace back papers and
read engineering reports from the ’60s and ’70s about this mission,
about different concepts, different ways to get this environment.”
What made the mission feasible was a set of technologies, including a
heat shield that protects the spacecraft during its close approach to
the sun as well as an active cooling system for the solar panels. The
spacecraft also needed to be small enough that it could be launched on
the desired trajectory.
“Certainly, finding the right materials” was key, said Fox. “It isn’t
just a case of surviving the incredible heat when we’re close to the
sun. We come out around Venus and it’s cold there, which means these
materials have to withstand heating and cooling, very extreme changes in
temperatures.”
Parker Solar Probe has a primary mission of 24 orbits around the sun
through the middle of 2025. Driesman, though, said he was optimistic
that the spacecraft could operate far longer. “As long as we have
propellant on board, we’re going to continue to take science data,” he
said.
The mission will ultimately end when the spacecraft runs out of
attitude control propellant. “It will lose attitude control and those
sensitive bits of the spacecraft, which we worked so hard to protect,
will eventually transition to the sun,” he said. “The way I like to
think about it is that, hopefully in a long, long period of time, 10 to
20 years, there’s going to be a carbon disk floating around the sun in
its orbit. That carbon disk will be around until the end of the solar
system.”
Parker Solar Probe will swoop to within 4 million miles of the sun's
surface, facing heat and radiation like no spacecraft before it.
Launching in 2018, Parker Solar Probe will provide new data on solar
activity and make critical contributions to our ability to forecast
major space-weather events that impact life on Earth.
In order to unlock the mysteries of the corona, but also to protect a
society that is increasingly dependent on technology from the threats
of space weather, we will send Parker Solar Probe to touch the Sun.
In 2017, the mission was renamed for Eugene Parker, the S.
Chandrasekhar Distinguished Service Professor Emeritus, Department of
Astronomy and Astrophysics at the University of Chicago. In the 1950s,
Parker proposed a number of concepts about how stars—including our
Sun—give off energy. He called this cascade of energy the solar wind,
and he described an entire complex system of plasmas, magnetic fields,
and energetic particles that make up this phenomenon. Parker also
theorized an explanation for the superheated solar atmosphere, the
corona, which is – contrary to what was expected by physics laws --
hotter than the surface of the sun itself. This is the first NASA
mission that has been named for a living individual.
Why Parker Solar Probe?
We live in the sun's atmosphere! This mission will provide
insight on a critical link in the Sun-Earth connection. Data will be key
to understanding and, perhaps, forecasting space weather.
We need to go so close because:
- the corona is unstable, producing the solar wind, flares and coronal mass ejections – we need to study at the source!
- millions of tons of highly magnetized material can erupt from the sun at speeds of several million miles an hour – fast enough to get from Washington to LA in seconds!