Mars, once a warm, watery world with a thick atmosphere.
Now, a cold, arid landscape with its atmosphere thinned out.
What caused this transformation?
Over billions of years, a relentless flow of particles from the Sun, the solar wind,
has slowly stripped away the Martian atmosphere,
causing surface water to evaporate.
But how exactly did this happen, and how could it affect future Mars explorers?
NASA's new ESCAPADE mission aims to find out.
The Escape and Plasma Acceleration and Dynamics Explorers
mission is studying the planet's real-time response
to the solar wind, helping us understand Mars' climate history.
Using two spacecraft in orbit for the first time.
Past missions that we've sent to Mars to understand, the interaction
of the solar wind with the planet have only been single spacecraft missions.
So ESCAPADE gives us what you might call a stereo perspective.
Two different vantage points simultaneously.
This will allow us to really make measurements
we’ve never made before, and to characterize
a system in a way we couldn't characterize it before.
ESCAPADE’s twin spacecraft fly in two different formations
to see how Mars responds to the solar wind in both time and space.
This is the first time that two or more spacecraft have worked out
a formation in orbit about another planet, in this case, Mars.
In the first formation, nicknamed the string of pearls,
the two spacecraft chase each other in nearly identical, highly-elongated orbits.
This allows ESCAPADE to observe rapid changes
in the Martian atmosphere, caused by sudden variations in the solar wind.
When we have two spacecraft crossing those regions in the quick succession,
we can monitor how those regions vary on timescales as short as two minutes,
up to 30 minutes. Before we had to wait for 4 or 5, six, seven, eight hours.
In the second formation, the spacecraft have different orbits
that are more separated from each other, allowing ESCAPADE to study both
the solar wind and the upper atmosphere of Mars simultaneously
for the very first time.
We'll have one spacecraft in the solar wind so we can measure what's coming in,
and then one spacecraft closer to Mars. This will help us understand
the cause and effect of what's happening when space weather comes to Mars.
ESCAPADE will not only fill gaps in the story of how Mars’ atmosphere changed.
It will also help us prepare to send human explorers to the Red Planet.
For example, ESCAPADE will give scientists more details about Mars' ionosphere,
a part of the upper atmosphere that future astronauts will rely on
to send radio and navigation signals around the planet.
Understanding how that ionosphere varies
will be a really important part of understanding
how to correct the distortions in those radio signals that we will need
to communicate with each other and to navigate on Mars.
ESCAPADE’s work could also help keep future Mars explorers safe.
Atmospheres can provide a shield that protect humans and
other assets on the surface
from things like solar radiation or intergalactic radiation.
So, it's important for us to understand how the atmosphere is changing in order
for us to know what we have to do to protect humans and other assets
we might put on the surface.
In addition to new science, ESCAPADE is pioneering a new way to reach Mars.
Previously, spacecraft launching to the Red Planet
had to wait years for Earth and Mars to line up.
However, ESCAPADE is launching into a unique orbit that loops around
a region in space known as L2, roughly a million miles away.
Then it'll return and use Earth's gravity to slingshot itself to Mars.
This allows ESCAPADE to launch early and wait in space until the two planets
are in the right positions.
This first-of-its-kind orbit will also make ESCAPADE
the only spacecraft to ever pass through a distant part of Earth's magnetotail
before beginning its ten-month cruise to Mars and starting its cutting-edge work there.
NASA's heliophysics fleet
is looking at the Sun's influence.
And with ESCAPADE, we’ll now have multi-point measurements at Mars,
which will help us have a more comprehensive picture
of what's happening throughout the solar system.
We need a solar system-wide understanding of space weather
in order to protect our technology and our astronauts wherever they go.