Moon Hides Mercury Tonight, Artemis II Tests Tomorrow, Saturn Ring Origin Revealed

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Hello, and welcome to Astronomy Daily.

I'm Anna.

And I'm Avery.

You're listening to season five episode 42

for Wednesday the 18th of February, 2026.

And what a day to be a space fan.

Absolutely.

Tonight, right now, in fact, the moon

is sliding so close to Mercury that it's actually

hiding it from view for Skywatchers

in parts of the Southern United States.

A genuine celestial magic trick happening as you listen.

And that's just one of six stories we're bringing you today.

We've got NASA's Artemis II on the verge

of a crucial fueling test.

A European rocket making a big move

in the satellite broadband race.

A genuinely new twist in the ongoing saga

of our interstellar visitor.

And two stories that I promise will make you rethink

some things you thought you knew about the solar system.

Big show.

Let's get into it.

So Anna, let's start with the biggest space story of the week.

And honestly, the one that could define the year.

Artemis II.

Yes, for anyone who needs a quick refresh,

Artemis II is NASA's first crude mission

around the moon since Apollo 17 in 1972.

Four astronauts, Reed Wiseman, Victor Glover, Christina

Koch, and Canada's Jeremy Hansen are preparing

to fly a 10-day loop around the moon and back.

No lunar landing, but a crucial proving flight

before we put boots on the surface.

And they are so close.

The rocket is sitting on path 39B

at Kennedy Space Center right now.

But before NASA will commit to a launch date,

they need to successfully do what's

called a wet dress rehearsal, a full practice countdown

where they actually load the rocket with fuel

and take it right to the edge of launch,

then drain it all out again.

They did that once already on February 3rd.

And it didn't go smoothly.

A liquid hydrogen leak cropped up,

the exact same kind of problem that plagued Artemis I three

years ago.

The countdown was terminated at T minus five minutes

and 15 seconds, close, but not close enough.

Which pushed the February launch window off the table entirely.

NASA Administrator Jared Isaacman was fairly

philosophical about it.

He said, this is exactly why you do a rehearsal

to find these issues before you're flying with crew.

But the clock is ticking.

Since then, engineers have replaced two seals

and a clogged filter in the hydrogen fueling system.

They ran a partial confidence test

on February 12th to check the repairs.

And now, tomorrow, February 19th,

they begin tanking day for the second full wet dress rehearsal.

This is the one that counts.

If the test goes cleanly, no ad of limits

hydrogen concentrations, countdown proceeds all the way

to the terminal phase, NASA will analyze the data

and set a launch date.

The current earliest possibility is March 6th.

It's worth noting just how historic this mission is

beyond the moon return angle.

Victor Glover will become the first person of color

to travel beyond low Earth orbit.

Christina Koch will be the first woman.

Jeremy Hansen will be the first non-American.

Every single person on that crew

is making history in their own right.

So tomorrow is genuinely a day to watch.

We'll be keeping a close eye on how the tanking goes

and we'll have updates as they come through.

All right, let's bring it back to Earth

or rather to the sky above Earth.

Because tonight is one of those rare evenings

where if you happen to be in the right place

and you look up at the right moment,

you'll see something genuinely extraordinary.

Two things, actually.

First, the moon and Mercury.

Tonight, February 18th,

a slender one and a half day old crescent moon

is passing extremely close to Mercury

in the western sky just after sunset.

And I mean extremely close.

For observers along a narrow band of southern US states,

we're talking Arizona, New Mexico, Texas, Louisiana,

Mississippi, and Georgia.

The moon will actually pass directly in front of Mercury

and block it from view entirely.

That's called an occultation.

Mercury literally disappears behind the moon's dark limb

and reappears on the other side.

For everyone else across North America and beyond,

it won't be a full occultation,

but you'll still see a dramatically close pairing.

East Coast observers will see Mercury

sitting just north of the moon as twilight falls.

By the time darkness reaches the west coast,

the moon will have shifted to within

about one degree of the planet.

Venus hangs brilliantly below them

as a helpful reference point.

Now, the window is tight.

Mercury sets not long after the sun.

So you want to get outside as soon as the sky darkens.

Look low in the west, southwest.

If you can spot Venus and you'll have no trouble doing that,

it's blazingly bright.

Mercury will be nearby.

The moon makes it easy tonight.

And if that weren't enough,

Jupiter watchers have a tree too.

Tonight, Ganymede, Jupiter's largest moon

and the biggest moon in the entire solar system,

is transiting across Jupiter's face.

East Coast observers can see it underway

as soon as it gets dark.

It takes just over three hours to cross the disc

and then Ganymede's shadow follows it across,

creating that striking black dot effect on Jupiter's cloud tops.

So tonight really is a two-for-one skywatching event.

Mercury and the moon in the west at dusk,

Jupiter and Ganymede in the southeast through the night.

If you have binoculars or a small telescope,

even better.

Get outside.

Staying with today's news,

and this one happened literally today.

Europe's Arian 6 rocket has successfully launched

32 satellites into orbit for Amazon's project Kuiper.

For those not familiar with Kuiper,

Amazon has been quietly building

a large constellation of broadband internet satellites

designed to take on SpaceX's Starlink.

This is a big commercial play.

Starlink currently leads the market

with thousands of operational satellites,

but Amazon has the resources and ambition

to make this a genuine competition.

What's notable about today's launch

is that it used the most powerful configuration

of Arian 6,

flying with four strap-on boosters rather than two.

It was essentially a statement of capability

from the European side of the commercial launch industry.

This rocket can handle serious payloads.

There's also a bigger picture here.

Arian 6 has had somewhat of a turbulent road.

It came in behind schedule

and faced some early technical hurdles,

but launches like this,

winning commercial contracts

for a high-profile constellation like Kuiper,

are exactly what Europe needs

to keep its launch industry competitive

in an era dominated by SpaceX

and an increasingly capable Chinese launch sector.

The broadband satellite race

is one of the defining infrastructure stories

of this decade, I'd argue.

Starlink has already changed

what connectivity looks like

in remote areas and conflict zones.

Hyper, Amazon's one-web investments,

the Chinese Go on constellation,

they all point to a future

where low-earth orbit

becomes genuinely critical economic territory.

Today's launch is one tile

in that much larger mosaic.

32 satellites closer to that future.

Now, an update on our interstellar visitor

and I do mean update.

There is genuinely new information here,

happening right now.

I know we've given three eye atlas

a quite a run over recent episodes,

but this one earns its place today.

Completely.

For new listeners,

three eye atlas is only the third interstellar object

ever confirmed to pass through our solar system.

It arrived from outside our stellar neighborhood,

swung around the sun last October

and is now heading back out into the galaxy forever.

We will never see this object again.

But here's what's happening right now.

He says juice spacecraft,

that's the Jupiter icy moon's explorer,

currently en route to Jupiter,

pass with an observational range

of three eye atlas back in November last year.

Due to the challenging thermal conditions

during juices transit through the inner solar system,

the data I collected couldn't be downlinked straight away.

That data is now being transmitted to Earth.

The window is February the 18th to the 20th today.

If successful,

these would be the closest ever observations

of an interstellar object by a spacecraft.

Now juice didn't do a dedicated flyby,

its trajectories locked in for Jupiter,

but even opportunistic observations

from its suite of cameras, spectrometers,

and particle detectors could give us a perspective

on three eye atlas that no Earth-phase telescope can provide.

And the data would complement

an extraordinary recent run of discoveries.

Hubble has directly imaged the nucleus for the first time.

Day WST detected methane in its atmosphere,

a molecule never before seen

in an interstellar object.

And the object is still spinning faster

than it was before its solar encounter,

a legacy of all that outgassing

as it swung close to the sun.

Three eye atlas is now about three and a half astronomical units

from the sun in the constellation Gemini.

It's fading, but still reachable

with a decent amateur telescope.

And it has one more big act to play,

a close pass by Jupiter in March,

which may trigger fresh outbursts

as Jupiter's tidal forces stress the nucleus.

An extraordinary object.

And the fact that we have a spacecraft data

downlink happening as we record today

makes it entirely current.

What report would juice found

as soon as a science team's released their analysis?

Right.

Deep time now, I genuinely love this next story

because it takes something you thought you understood,

Saturn's rings, and reframes

the entire origin of the system.

New research by Mattia Chouk at the City Intitude

about to be published in the Planetary Science Journal

proposes a dramatic two-stage catastrophe

that reshaped the entire Saturnian system

roughly 400 million years ago.

And I mean reshaped everything.

Titan, the rings, hiapidus, Hyperion,

all of it connected to one ancient collision.

Let's set the scene.

Saturn has puzzled planetary scientists for a long time.

Its axial tilts is an unusually steep 26.7 degrees.

You don't expect gas giants to form that way.

Titan is migrating away from Saturn

at a surprisingly rapid rate.

The moon hiapidus sits at an oddly inclined orbit

and the rings are far younger than the planet itself,

only a few hundred million years old, geologically speaking.

One thing after another that didn't quite add up.

Juke and colleagues ran simulations

and found a scenario that explains it all at once.

The key player is a moon they're calling proto-hyperion.

Saturn used to have this additional mid-sized satellite

orbiting in the outer system.

When Saturn spin orbit resonance

with the other planets in the solar system broke down,

proto-hyperion was destabilized.

It drifted inward and it collided with a proto-titan.

The merger of those two moons, roughly 400 million years ago,

set off a chain reaction.

Some of the collision debris accreted around

what would become today's Titan,

explaining why Titan's surface looks surprisingly young

despite the moon itself being ancient.

Titan absorbed new material

and essentially reset its surface.

Other debris from the collision

perturbed the inner moon system.

Titan's resonant gravitational interaction

with proto-dyone and proto-raya caused further instabilities.

More collisions, more debris.

Most of that material eventually re-accreted

into the inner moons we see today.

Mimus, Enceladus, Tethis, Dione, Raya.

But a fraction of it stayed dispersed.

That fraction became Saturn's rings.

And Hyperion, the small, oddly shaped walnut-like moon

that looks like it survived a very bad day.

According to the model, it actually did survive a very bad day.

It formed from the debris of that proto-hyperion

and proto-titan collision and was captured

into resonance with Titan.

The researchers note that in most of their simulations,

Hyperion was lost entirely.

Its survival in a relatively small number of runs

suggests the real system was genuinely close

to being quite different.

What I find compelling about this

is how elegantly one event connects everything.

The tilt of the whole planet, the age of the rings,

the orbits of biopetus and Hyperion,

Titan's migration rate.

One ancient merger explains it all.

Now, the researchers are careful to say

this is a hypothesis, not a confirmed history.

Simulations can be suggestive

without being definitive.

But NASA's Dragonfly mission is heading to Titan.

It launches in 2028 and arrives in 2034.

One of the things Dragonfly will investigate

is the age and history of Titan's surface.

If the surface shows evidence of that ancient resetting,

that would be a powerful confirmation.

400 million years of cosmic history

hiding in a walnut-shaped moon.

I love this stuff.

And finally, a story that will make you rethink

just how long it takes to get to Mars,

or at least how long it might take one day.

Russia's state nuclear corporation, Rosatom,

through its Troyes Institute near Moscow,

has been developing a nuclear-powered magna-plasma engine

and they're making a bold claim

that this technology could get a crude spacecraft

to Mars in 30 days.

To put that in context, a conventional chemical rocket

takes roughly eight months to reach Mars.

30 days would be a transformation, not just an improvement.

It would fundamentally change the feasibility

of human Mars missions, less radiation exposure

for the crew, less time in microgravity,

a completely different logistical calculus

for resupply and emergency scenarios.

The engine works by accelerating hydrogen

using electromagnetic fields rather than combustion

to a velocity of 100 kilometers per second.

That's roughly 22 times faster

than the exhaust velocity of a conventional chemical rocket.

The working body is plasma, charged particles,

and it's driven by an onboard nuclear reactor

that provides the sustained electrical power

the accelerator needs.

Importantly, this isn't a launch engine.

You'd still use conventional chemical rockets

to get off Earth's surface and into orbit.

The plasma system switches on once you're in space

for the interplanetary crews.

Smooth, continuous acceleration followed

by a long deceleration burn.

The prototype is currently running ground trials

inside a 14 meter vacuum chamber

designed to replicate deep space conditions.

The researchers say the engine has demonstrated

sufficient longevity over 2400 hours

for a Mars transportation operation.

A flight-ready prototype is targeted for 2030.

Now, and this is important, there are real caveats here.

No peer-reviewed data has been published yet.

The thrust is very low around six newtons.

Integrating a nuclear reactor into a crude spacecraft

is an enormous engineering challenge in itself

with regulatory, thermal, and radiation shielding hurdles

that remain largely unsolved publicly.

Bear points, but the broader context is genuinely interesting.

NASA is investing in its own plasma propulsion programs.

The Vazimir engine from Ad Astra Rocket Company in Texas

targets a Mars trip of 45 to 60 days.

China has plasma thruster research underway too.

There's a real multi-nation push

to solve the propulsion problem for deep space travel.

Chemical rockets got us to the moon,

getting to Mars regularly, safely,

and at human time scales requires something different.

This is where that search is heading.

Wherever it ultimately leads.

30 days to Mars.

Even as an aspiration, that's a sentence we're sitting with.

And that's our six stories for season five episode 42.

What a lineup from a rocket on a launch pad in Florida

to a crescent moon's swallowing mercury,

to the debris of a 400 million year old collision

still orbiting Saturn.

And an interstellar comet sending us its last data

from the edge of the solar system.

While Russia dreams of getting to Mars in a month,

base never has a quiet week.

If tonight's sky events caught your attention,

there is still time to get outside.

Mercury and the moon in the west,

Jupiter and Ganymede in the southeast.

You have your orders.

And keep an eye on Artemis.

Tomorrow's fueling test is one of those days

where the news could come fast.

We'll be on it.

Thank you so much for spending part of your Wednesday

with us.

We'll be back tomorrow for more from the universe.

Until then, clear skies, everyone.

The sunny day, the star is the toll.

The star is the toll.

Tyler Reddick here from 2311 Racing,

another checkered flag for the books.

Time to celebrate with Jamba.

Jump in at JambaCasino.com.

Let's Jamba.