Ireland Joins the Artemis Coalition, Nuclear Mars Mission Advances & Halley's Meteor Peak

0:00 Anna: Hello and welcome to Astronomy Daily.

0:03 I'm Anna.

0:04 Avery: And I'm, um, avery. It's Monday, May 4,

0:06 2026. And yes, may the 4th be with

0:09 you.

0:10 Anna: But while you're looking up for X wings and

0:13 TIE fighters, keep your eyes peeled for

0:15 something very real shooting across the skies

0:18 tonight because Halley's Comet has left us

0:21 a little gift.

0:22 Avery: That's right, the Eta Equinarians meteor

0:25 shower is peaking this week. And for our

0:27 Southern Hemisphere listeners in Australia,

0:29 New Zealand and beyond, it could be spectac.

0:32 Anna: We have that story and five more today,

0:34 including Ireland joining the Global Space

0:37 Coalition, the next moon rocket's backbone

0:40 arriving at Kennedy, and a, uh, nuclear

0:43 powered mission to Mars that sounds like

0:45 science fiction, but is very much science

0:47 fact.

0:48 Avery: And we'll visit two rovers having very

0:50 different days on the Red planet and meet a

0:52 galaxy that turns out to be a first time

0:54 visitor to our cosmic neighborhood. Let's get

0:57 into it.

0:57 Anna: We start today with a historic signing

1:00 happening right now as we record Ireland

1:03 is joining the Artemis accords, becoming the

1:06 65th nation to commit to responsible and

1:09 peaceful space exploration.

1:11 Avery: The ceremony is taking place at NASA

1:12 headquarters in Washington, D.C. today,

1:14 Monday, May 4, hosted by NASA

1:17 Administrator Jared Isaacman, alongside

1:19 Ireland's Ambassador to the US Geraldine

1:21 Byrne Nason and Minister for Enterprise Peter

1:24 Burke.

1:25 Anna: Now, for listeners who may be new to the

1:27 show, the Artemis Accords are a set of

1:30 principles established back in 2020

1:32 during the first Trump administration, and

1:35 they've grown steadily since. They cover

1:37 everything from peaceful exploration and

1:40 transparency to protecting historically

1:43 significant sites in space and ensuring

1:45 scientific data is shared openly.

1:48 Avery: What's notable here is the pace at which

1:50 nations are joining. Just two weeks ago,

1:52 Latvia signed as a 62nd signatory.

1:55 Then Morocco joined as the 64th last week,

1:58 and now Ireland makes 65. That's

2:01 three new nations in a fortnight.

2:02 Anna: Ireland actually has a, uh, growing space

2:05 sector. It's home to the European Space

2:07 Agency's European Space Astronomy center

2:10 operations and has been part of ESA for

2:13 decades. Joining the Accords formalizes

2:16 its commitment to the broader international

2:18 framework for lunar and deep space

2:20 activities.

2:22 Avery: With 65 nations now on board, the Artemis

2:24 Accords represent the most extensive

2:26 multilateral framework for space exploration

2:29 ever assembled. And the list keeps growing.

2:31 As NASA says all countries are welcome,

2:34 whether or not they have their own space

2:35 program.

2:36 Anna: A lovely milestone to mark on May 4th of

2:39 all days.

2:40 Avery: Well, Ireland did pick a memorable date,

2:43 dory2.

2:43 Anna: And we are staying firmly in the Artemis

2:46 universe. The ink is barely dry on the

2:49 Artemis 2 mission. Reid Wiseman, Victor

2:51 Glover, Christina Koch and Jeremy Hansen

2:54 splashed down just three weeks ago, and

2:57 NASA is already pressing ahead at pace.

3:00 Avery: The massive core stage of the Space Launch

3:02 Systems rocket for Artemis 3 arrived at

3:04 Kennedy Space center in Florida last week on

3:07 April 27, completing a 900 mile

3:10 journey by barge from NASA's Michaud Assembly

3:12 Facility in New Orleans.

3:14 Anna: And when we say massive, we mean it.

3:17 The SLS core stage is

3:19 212ft tall. When fully

3:22 assembled, it houses two propellant tanks

3:25 that together hold over

3:27 733,000 gallons

3:30 of super chilled liquid propellant to feed

3:33 four RS25 engines. It's the

3:36 heart of the most powerful rocket currently

3:38 flying.

3:39 Avery: The core stage is now inside the vehicle

3:41 assembly bab, the vab, where it will be mated

3:44 to its engine section. And NASA has been

3:46 running everything in parallel. Solid rocket

3:49 booster segments have already arrived by rail

3:51 from Utah. And the mobile launcher was

3:53 returned to the VAB even before the barge

3:56 docked.

3:57 Anna: Now here's where Artemis 3 gets interesting.

4:00 Because this mission is not going to the

4:02 moon's surface, its job is to test the

4:05 rendezvous and docking capabilities between

4:07 the Orion spacecraft and the commercial

4:10 landers, SpaceX's Starship and Blue

4:13 Origin's blue moon in low Earth orbit.

4:16 Think Apollo 9, which did the same kind of

4:19 dress rehearsal in 1969.

4:21 Avery: That groundwork is critical because it's

4:23 Artemis 4 that will actually put astronauts

4:26 back on the lunar surface targeted for

4:28 2028. So Artemis 3,

4:31 likely launching in late 2027, is

4:34 the essential bridge.

4:36 Anna: There's something exhilarating about seeing

4:38 hardware arrive. It's real, it's

4:41 tangible, it's happening. Artemis,

4:44 as one NASA official put it last week, is

4:47 full steam ahead.

4:49 Avery: Story three, and we're venturing a little

4:51 further out to Mars and the most audacious

4:54 propulsion experiment in decades. NASA

4:57 is pressing ahead with plans to launch the

5:00 world's first nuclear electric powered

5:02 interplanetary spacecraft in December

5:05 2028.

5:06 Anna: It's called Space Reactor One Freedom

5:09 SR One Freedom for short. And if it

5:12 launches on schedule, it will be the first

5:14 spacecraft to use nuclear fission for

5:16 propulsion since the 1960s.

5:19 Over 60 years in the making,

5:22 the

5:22 Avery: concept is called Nuclear Electric

5:24 propulsion, or nep.

5:27 Unlike nuclear thermal propulsion, which

5:29 heats propellant directly, NEP uses

5:32 a fission reactor to generate electricity,

5:35 which then powers highly efficient ion

5:37 thrusters. The spacecraft accelerates slowly

5:40 at first, but continuously building up

5:43 extraordinary speed over weeks.

5:45 Anna: The reactor itself will produce 20

5:48 kilowatts of electrical power using high

5:50 assay low enriched uranium. And in

5:53 a clever piece of engineering pragmatism,

5:56 NASA is repurposing hardware that was already

5:59 built for the now paused lunar gateway

6:01 program, the power and propulsion element

6:04 as the spacecraft bus.

6:07 Avery: Once SR1 Freedom reaches Mars roughly a

6:10 year after launch, it will deploy a payload

6:12 called Skyfall three Ingenuity class

6:15 helicopters that will scout the martian

6:17 surface for subsurface water ice and

6:20 survey potential future human landing sites.

6:23 Anna: Ingenuity, you'll recall, was only supposed

6:25 to fly five times. On the Perseverance

6:28 mission, it flew 72. So

6:30 NASA knows these little rotorcraft can punch

6:33 well above their weight.

6:35 Avery: NASA Administrator Isaacman announced the

6:37 mission back in March at what they called the

6:40 ignition event, and he was emphatic this

6:43 isn't a concept study. Hardware development

6:45 is ramping up now with assembly and testing

6:48 scheduled from early 2028. The December

6:51 2028 Mars launch window is the deadline, and

6:54 the scope bends around it.

6:56 Anna: If successful, SR1 freedom does

6:59 far more than test a propulsion system. It

7:02 establishes the regulatory and launch

7:04 precedents for nuclear hardware in space,

7:07 activates the industrial base, and opens the

7:10 door to megalot class reactors that could one

7:13 day cut a human journey to Mars to just

7:15 two months.

7:16 The stakes couldn't be higher now for

7:19 Avery: something you can actually go outside and

7:21 experience yourself because the ADA

7:24 Aquarids meteor shower is peaking right now

7:27 with the best viewing on the mornings of May

7:29 5th and 6th.

7:31 Anna: And we know we've touched on this in recent

7:33 episodes, but the peak is literally upon us.

7:36 So here's your final briefing and viewing

7:38 guide.

7:39 Avery: The ETA Aquarids are one of the most famous

7:42 annual meteor showers, and they come from a

7:44 truly iconic source, the debris trail of

7:47 Halley's Comet. Earth passes through

7:50 Halley's dusty wake each May. Those

7:52 particles, some as small as a grain of sand,

7:55 slam into our atmosphere at around 66

7:58 km per second and vaporize in

8:00 brilliant streaks of light.

8:03 Anna: Halley's Comet last visited the inner solar

8:05 system in 1986 and won't return

8:08 until 2061. So these annual

8:11 showers are our way of staying connected to

8:14 one of the most celebrated objects in

8:16 astronomical history.

8:18 Avery: Now, the great news for our Southern

8:20 Hemisphere listeners, and that's a lot of you

8:23 in Australia, New Zealand, and South Africa,

8:26 is that this shower strongly favors your

8:28 skies. The radiant point in Aquarius

8:31 climbs much higher before dawn in the

8:34 southern latitudes, giving you potential

8:36 rates of around 50 meteors per hour under

8:39 ideal dark sky conditions.

8:41 Anna: The challenge this year is the moon. On the

8:44 peak night, we have a waning gibbous moon

8:46 that's about 84% illuminated, which will wash

8:49 out the fainter meteors. The best strategy is

8:51 to find a dark location and physically block

8:54 the moon behind a treeline, building or hill,

8:57 your eyes will adjust and you'll catch the

8:59 brighter, faster meteors.

9:01 Avery: Even so, the pre dawn hours are, uh, the

9:04 prime window. Watch from around 2am

9:07 onwards as the radiant climbs highest. These

9:10 are fast meteors that often leave glowing,

9:12 persistent trails. Set up a reclining

9:15 chair, wrap up warm, yes, even in

9:18 autumn for you southern listeners and let the

9:20 skies do the rest.

9:21 Anna: The shower remains active through May 28,

9:25 so there are more opportunities ahead, even

9:27 if clouds interrupt tonight. But the peak is

9:30 now. Get out there.

9:31 Avery: Story five takes us to the Red Planet, where

9:34 two remarkable robots are currently writing

9:37 history from opposite ends of geological

9:40 time. NASA has released sweeping

9:42 360 degree panoramas from both Curiosity

9:45 and Perseverance. And together they tell

9:48 one of the most compelling stories in

9:50 planetary science.

9:52 Anna: Here's the beautiful paradox of what's

9:54 happening. Curiosity, now approaching 15

9:57 years on Mars, is climbing Mount Sharp

10:00 and exploring progressively younger terrain.

10:03 Perseverance, just five years in, is heading

10:06 into some of the oldest landscapes in the

10:08 entire solar system. They're time traveling

10:10 in opposite directions.

10:12 Avery: Curiosity's new panorama is assembled from

10:15 over a thousand images captured between

10:17 November and December last year. It reveals

10:20 a vast network of what scientists call

10:23 boxwork formations, low ridges that

10:26 from orbit look like giant spiderwebs etched

10:29 across the landscape. These ridges formed

10:31 billions of years ago when groundwater flowed

10:34 through fractures in the bedrock, depositing

10:36 minerals that hardened everything around them

10:39 eroded away. What's left is essentially

10:42 a fossil of ancient water activity.

10:45 Anna: Perseverance is panorama focuses on a region

10:47 near the rim of Jezero Crater, a place

10:50 nicknamed Lac des Charmes. Assembled from

10:53 nearly 980 images taken over

10:56 several weeks in late 2025 and early

10:59 2026. The crater held a lake

11:02 billions of years ago, fed by a river system.

11:05 The sediments that filled that lakebed could

11:07 have preserved signs of microbial life. In

11:10 2024, Perseverance found a rock called

11:13 Chayava Falls, covered with what scientists

11:16 call leopard spots caused by chemical

11:19 reactions that microbes are known to

11:22 Earth.

11:22 Avery: And Perseverance is carrying 23

11:25 intact rock cores in sealed tubes,

11:28 waiting for a future sample return mission to

11:30 bring them to Earth labs. The science

11:33 locked inside those tubes could quite

11:35 literally answer the question of whether life

11:38 ever existed beyond our planet.

11:41 Anna: These panoramas aren't just beautiful,

11:43 although they absolutely are. At over a

11:46 billion pixels, curiosities alone is one

11:49 of the largest it's ever taken. There's

11:51 scientific archives, time capsules,

11:54 two snapshots of a world that was once warm

11:57 Wet and possibly alive.

12:00 Avery: Two rovers,

12:01 3,775km

12:04 apart, filling in the missing chapters of

12:06 Mars's extraordinary biography.

12:09 What a time to be alive.

12:11 Anna: And our final story today is one for anyone

12:14 who's looked south on a clear night and seen

12:17 those two glowing smudges in the sky, the

12:19 Large and Small Magellanic Clouds. If you're

12:22 in Australia or New Zealand, they're part of

12:25 your night sky heritage. But new research

12:27 suggests their history is far stranger than

12:30 we ever imagined.

12:32 Avery: The Large Magellanic Cloud, the LMC

12:35 is our galaxy's most massive satellite.

12:38 For decades, astronomers assumed it had been

12:40 orbiting the Milky Way for billions of years,

12:43 making multiple passes. A competing theory

12:46 said it's actually on its first approach.

12:49 Now a new preprint paper claims to provide

12:51 what the authors call definitive evidence

12:54 that the LMC is a first time visitor.

12:57 Anna: The paper comes from researchers including

12:59 Scott Luccini and colleagues, and it

13:01 addresses a fierce ongoing debate in

13:04 astrophysics. The stakes are high because the

13:06 LMC is genuinely massive. It's roughly

13:09 one tenth to one fifth the mass of the Milky

13:12 Way itself. A galaxy that big, swinging

13:14 through our neighborhood sends gravitational

13:17 shock waves through everything around us.

13:19 Avery: The evidence lies in the LMC's corona, a, uh,

13:22 diffuse halo of warm gas surrounding it. If

13:25 the LMC had made a previous close pass by the

13:28 Milky Way, that corona should have been

13:30 stripped away by our galaxy's gravity. The

13:32 fact that it's still there, relatively

13:35 intact, strongly supports the first infall

13:37 scenario. It also explains why the Small

13:40 Magellanic Cloud and other satellites, ah,

13:42 that travel with the LMC haven't been tidally

13:45 torn apart. They simply haven't had enough

13:48 close encounters with the Milky Way to be

13:50 disrupted.

13:51 Anna: There's something almost poetic about this.

13:53 That gorgeous smudge of light you can see

13:55 from a southern dark sky visible to the naked

13:58 eye, named after Magellan, is essentially a

14:01 first time visitor. It fell toward us for the

14:04 first time in cosmic history, passed its

14:06 closest point recently in astronomical terms,

14:09 and now is swing back out. We're

14:11 witnessing something that has never happened

14:14 before in our galaxy's history.

14:16 Avery: It also rewrites our understanding of the

14:18 Magellanic Stream, that vast trail of

14:20 hydrogen gas stretching across the southern

14:23 sky behind the clouds. That stream was

14:25 thought to have been shaped by multiple Milky

14:28 Way interactions. Now researchers have to

14:30 explain it through LMC SMC interactions

14:33 alone. More work ahead. But what a puzzle to

14:36 have for

14:37 Anna: our Southern Hemisphere listeners. Next time

14:39 you step outside on a clear night and spot

14:41 the Magellanic Clouds, take a moment. You're

14:44 watching a, uh, first encounter between

14:46 galaxies unfolding in slow motion

14:48 across the cosmos.

14:50 Avery: And that's your Astronomy daily for Monday,

14:52 May 4. Six stories from Ireland

14:55 joining the Space Coalition to a galaxy

14:58 making its first visit in cosmic history.

15:01 What a day to be an astronomy.

15:02 Anna: Enthusiastic if you're heading out to watch

15:04 the IDA Aquarids tonight or tomorrow morning,

15:07 we'd love to hear how you got on. Find us at

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15:17 Avery: And if the show brings you joy, please leave

15:19 us a review. Wherever you listen, it

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15:25 Anna: This has been Astronomy Daily, part of the

15:27 bytes.com podcast network. I'm Anna

15:30 and just before I go, a quick reminder to

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15:45 Avery: notes and I'm Avery. Keep looking up.

15:48 The universe has never been more alive.

15:51 We'll see you tomorrow.

15:55 Anna: Mhm.

16:03 The story.