Anna: Hey, everyone. Welcome back to Astronomy
AstroDailyPod. I'm Anna.
Avery: And I'm avery. It's Tuesday, August 18th,
series five, episode 170.
Anna: And we've got a genuinely satisfying one to
lead with today.
After three weeks of, uh, will they, won't
they? SpaceX has actually pulled its
starship upper stage out of the Indian
Ocean.
Avery: Ship 40 makes it home, closing the loop on a
storey we've been checking in on since it
splashed down back on July 24th.
Anna: Then three more. A dead star in a
nearby nebula that's basically showing us our
own sun's obituary five billion
years early. New evidence that the Milky
Way itself was built out of a galaxy we
crashed into almost 12 billion years ago.
And China bouncing back fast from a
rocket explosion with two launches in about
23 hours, plus a quick one for
Avery: anyone stepping outside tonight, there is a
nice pairing in the western sky right after
sunset.
Anna: Lots to get through. Let's get into it.
Avery: Okay, so let's actually finish this storey,
Anna, uh, take us back to the start, because
it's been a genuine saga.
Anna: It has. This goes back to July
24 and Starship's Flight 13.
The upper stage ship 40 did something
no Starship upper stage had ever managed
before. It flipped, reignited two
engines, oriented itself and made a
controlled soft splashdown in the Indian
Ocean off Western Australia, completely
intact.
Avery: Which nobody was really planning for. Usually
these things topple over and break apart on
impact.
Anna: Right? That was the original good news
storey. SpaceX got an intact upper
stage sitting on the water and decided that
was too good an opportunity to just scuttle
it. They sent recovery vessels out, the
Normand Ranger, the Go Australis, a
ship called Skimmer Tide, and started trying
to lasso a, uh, 170 foot
stainless steel rocket that had drifted more
than 400 kilometres from where it landed.
Avery: And that's when it got complicated.
Anna: Very complicated. The tow back toward shore
started in early August, but the seas
didn't cooperate. Conditions kept
deteriorating. The convoy could only creep
along at 1 to 3 knots. And on
August 8th, Elon Musk gave us the line we led
an episode with a couple of weeks ago. Ship
recovery is not looking good right now.
Avery: And, um, prediction markets had it down
around an 18% chance of actually making it to
shore.
Anna: That's right where it sat for a while. But
here's the actual news today. It worked.
Over the past few days, the Normand Rangers
convoy got ship 40 secured, built up
speed and towed it all the way in toward
Dampier in Western Australia. As of this
week, SpaceX has recovered
Avery: the ship three weeks adrift and they actually
brought it home.
Anna: Three weeks, more than 400 kilometres of
drift, rough seas that nearly sank the whole
recovery effort, and an intact
170 foot Starship upper stage
sitting on a dock instead of on the seafloor.
That's a first.
Avery: What do they actually get out of having the
physical vehicle back versus just the imagery
they'd already collected?
Anna: That's the interesting part. SpaceX had
already said the mission's main objective was
done regardless of outcome because they got
close up satellite and drone imagery of the
heat SH and engine sections while ship
40 was still floating. That inspection showed
the thermal protection system mostly held up
despite higher than expected aerodynamic
pressure during ascent. Though there was some
tile loss and damage around the aft rim that
happened earlier in flight.
Avery: So having the actual hardware back is a bonus
on top of an already successful data run.
Anna: Exactly. Now engineers can do hands
on forensic inspection instead of just
working from photos, which is a much richer
way to validate what held and what didn't for
the next generation of ships.
Avery: And the programme hasn't exactly been
standing still waiting for this to resolve.
Anna: Not even slightly. Jip41
has already been through cryogenic testing
and engine installation and it's expected to
roll out to the Massey's test site for static
fire testing as early as this week.
Booster 21's finished its own cryo campaign
and is having engines installed for its
static fire and Flight 14. The
next full test flight is currently targeting
around August 20th. So just a couple of days
from now.
Avery: So this whole saga wraps up almost exactly as
the next chapter is about
Anna: to start, which is very on brand for
this programme. At the moment there's
basically no gap between close one storey and
open the next one. But Gregor has also been
busy in the background. SpaceX ran 22
separate Raptor 3 engine firings there over
the last two weeks, including one that ran,
ah, a full 140 seconds, matching
a complete ascent burn.
Avery: That's a lot of engines getting put through
their paces. For a rocket that's supposedly
still in
Anna: a testing phase, it's the clearest sign yet
that they're trying to get the cadence up.
Anyway, ship 40's home after three weeks
of is it lost at sea? It isn't.
Good outcome and one less loose thread for us
to keep tracking.
Avery: We can finally stop saying still unresolved
about this one.
Anna: Next storey is, uh, a bit more melancholy,
but in a genuinely beautiful way.
Astronomers have gotten the clearest look yet
at what happens to A star like our sun after
it dies.
Avery: And, uh, we're talking about the sun's actual
eventual fate here.
Anna: Not a metaphor, not a metaphor at
all. This comes from the helix Nebula, about
650 light years away in the constellation
Aquarius, one of the closest and most
photographed planetary nebulae there is. At
its centre sits a white dwarf, the dense
leftover core of a sun like star that
ran out of hydrogen fuel, ballooned into a
red giant and then shed its outer layers into
space.
Avery: Which 5 billion years from now is exactly
what's going to happen to our sun.
Anna: Precisely. This is our own star's
future. Just further along the timeline, a
team led by Peter Van Daakum at Yale, along
with Roberto Abraham at the University of
Toronto and Imad Pasha at the
Dragonfly Focused Research Organisation
studied the nebula's outer faint halo and
found something nobody directly resolved
before.22 distinct arc
shaped structures called bow shocks,
essentially wakes left behind as clumps of
the dead star's ejected material plough
through the surrounding interstellar gas.
Avery: So we're watching the star's old outer layers
actually being absorbed back into the galaxy?
Anna: That's the headline. This is the first direct
observation of stellar debris being broken
apart and returned to the interstellar medium
in real time. Van Daukum put it simply,
we are seeing material shed near the end of a
star's life being broken apart and returned
to the galaxy.
Avery: How long does that process actually take?
Anna: Relatively fast on cosmic timescales. The
researchers estimate those clumps survive for
around 10,000 years before they fully
disperse and blend into the surrounding gas.
The nebula's outer ring itself spans about
5.7 light years.
Avery: So this is basically recycling the star's
guts eventually become raw material for the
next generation of stars and planets.
Anna: That's exactly the point. Every heavy element
in your body that isn't hydrogen or helium
came from a star that did this at some point.
Watching it happen in real time, even in a
nebula that's already thousands of years into
the process, is about as close as we get to
watching that recycling loop in action. The
results were published Aug. 12 in Nature.
Avery: A nice one to sit with. Not a disaster
storey, just the actual shape of how stars,
um, end.
Anna: And a preview of a very, very distant
Tuesday 5 billion years from now.
Avery: Storey 3. And this one's about our home
galaxy's own deep history, Right?
Anna: New research using Hubble, backed up by data
from ESA's GAIA mission, has identified
a previously unknown collision that helped
shape the Milky Way almost 11 billion years
ago.
Avery: Previously unknown, is doing some work there.
How do you find a collision that happened
that long ago?
Anna: You look at the fossil record it left behind.
Specifically, globular clusters, these dense
balls of hundreds of thousands of old stars
that orbit the galaxy. A team led by
Davide Massari at Bologna's
Astrophysics and Space Science Observatory,
with Kiara Zerbinati from the University of
Bologna doing key analysis of the Hubble and
Gaia data, found a distinct population
of globular clusters that didn't match any
previously known building block of the Milky
Way.
Avery: So a whole separate family of star clusters
just hiding in plain sight.
Anna: Hiding in plain sight for decades, basically,
because until you have precise enough motion
and composition data, one old globular
cluster looks a lot like another. This third
population traces back to a dwarf galaxy.
The team's calling LKH for
low energy Kraken Heracles, which
merged with the Milky Way about 11.8
billion years ago, just roughly 2 billion
years after the Big Bang.
Avery: How big was this thing?
Anna: Relatively speaking, modest by
galaxy standards, around 500 million
solar masses. But it brought its own globular
clusters along with it, which merged into the
Milky Way's own population. And the collision
likely triggered bursts of star formation and
contributed meaningfully to our galaxy's
early chemical makeup.
Avery: And this is a different event from the Gaia
sausage Enceladus merger, the one we've
mentioned before as the Milky Way's biggest
ancient collision.
Anna: Different and earlier. LKH
predates that Gaia Sausage Enceladus merger
by about 1.8 billion years. So
this pushes the known history of the Milky
Way's construction by collision back even
further than we'd already mapped.
Avery: It's a good reminder that the Milky Way isn't
really one continuous thing. It's more like a
scrapbook of everything it swallowed.
Anna: Which is exactly the sentiment Messari
captured. He said, our home is the Milky Way
galaxy, but we do not know how our house was
built. This is one more floorboard in that
house getting identified. The findings were
published August 18th in Nature Astronomy.
Avery: Somewhere between the LKH merger and Gaia
sausage Enceladus, our, uh, galaxy basically
had two formative growth spurts back to back.
Anna: And there's likely more of these still hiding
in the data. This is very much an ongoing
excavation.
Okay, on to our last storey today and a
quicker one. China's space programme had a
rough moment last week, and a strong recovery
this
Avery: week set the scene.
Anna: What happens on August 10th? A Long March
7A rocket failed about 85
seconds into flight. The Fairing and upper
section of the vehicle bent backward and
broke apart, destroying the rocket along with
its payload. A communications satellite,
Zongshang 4B. The cause is still
under investigation, which
Avery: is obviously a serious loss. Both a rocket
and a comm satellite gone it is.
Anna: And there was a real question of how quickly
China's programme could get back to flying
after that kind of very public failure. The
answer turned out to be fast. On August
16, they launched twice within about
23 hours, using two completely different
rockets from two different sites.
Avery: Walk us through both.
Anna: First up was a long March 12 from the
Wenshang Commercial Space Launch Site,
carrying 24 Internet satellites into low
Earth orbit. That's the long March 12's
seventh consecutive successful mission since
it debuted in 2024. Then about
23 hours later, a long March
2C lifted off from the Taiwan Satellite
Launch Centre roughly 1300 miles to
the north, carrying a satellite for the
United Arab Emirates.
Avery: Um, and the IIC is the old reliable of the
fleet, right?
Anna: By a wide margin. That airframe's been flying
since 1982. So the message
China's sending here is pretty deliberate.
Newer commercial rocket, decades old
workhorse rocket, two different launch sites,
back to back. Less than a week after a very
Avery: public failure, a calculated show of
operational depth rather than just look, we
launched
Anna: something that's exactly the read on it,
proving the failure was contained to that.
One rocket and one pad. Not a symptom of
something systemic across the programme.
Avery: A quick one before we go. If you step outside
after sunset tonight, look low in the western
sky.
Anna: The waxing crescent moon, just a few days
old, is keeping company with Venus tonight.
And Venus is blazing away at magnitude
-4.1, so it's genuinely hard
to miss. About 45 minutes after sunset.
Avery: Um, an easy, no telescope required, one for
tonight.
Anna: Okay, that's today's episode. Starship's ship
40 finally makes it home after three weeks
adrift a dead star, showing us our
Sun's own distant future. New evidence
the Milky Way was built out of an ancient
galactic collision and China's fast
recovery with back to back
Avery: launches, plus tonight's Moon and Venus
pairing. If you get a clear sky.
Anna: If you enjoyed today's episode, the best
thing you can do for us is leave a rating or
review wherever you're listening and share it
with a fellow space nerd. Full show notes,
sources and links for every storey we covered
today are at, uh, astronomydaily IO
and you can find us on social media. We're
astrodaily Pod pretty much everywhere.
Avery: We'll be back tomorrow with more from the
world of space and astronomy. Until then,
keep looking up.
Anna: See you then. Clear skies, everyone.
Astronomy day.
Avery: The storeys be told.
Anna: Storeys.