Forty Times Brighter Than the Full Moon: Inside the Space-Mirror Fight

0:00 Anna: Here we go. Hi everyone. Welcome back to Astronomy AstroDailyPod. I'm Anna. Avery: And I'm um, avery. It's Friday, August 28th. Series 5 Episode 179 Today's Lead Storey Anna: is one of those genuinely new dilemmas. As we reported a few weeks ago, a US startup just got the green light to put a giant mirror in orbit and beam sunlight down to Earth at night. And astronomers are understandably not happy about the maths on how bright that actually is. Avery: Then Starship's, um, next flight quietly slips a few weeks while the last one is finally on its way home by ship.

0:38 A hot little exoplanet that's living on borrowed time and the Roman Space Telescope two days from launch with a budget survival storey we haven't told you yet. Anna: Let's get into it. Avery: Okay, this first one sounds almost too on the nose. Mirrors in space aimed at Earth. Anna: That's exactly it. Uh, a US startup called ReflectOrbital wants to put tens of thousands of large mirrors into low Earth orbit and use them to beam reflected sunlight down to specific spots on the ground on demand, even at night.

1:12 And back in July, the FCC actually approved their first demonstration satellite. Avery: Approved it to do what exactly? Anna: To launch and operate a satellite called Earendil 1, about 600 kilometres up, carrying a reflective mirror roughly 60ft on a side. That's just the demo. The company's actual business plan is a constellation of more than 50,000 mirrors by 2035, with the operational versions much bigger, again around 174ft or 54 metres per side. Avery: And um, the pitch is what free Anna: nighttime sunlight pretty much reflect.

1:51 Orbital's pitch is extending solar panel output into the night, lighting disaster and search and rescue zones without needing generators, letting construction and outdoor work run longer hours. Even carbon free street lighting. On paper, it's a genuinely interesting idea. Controllable, targeted daylight wherever and whenever you need it. Avery: So where's the catch? Anna: The catch is what it does to everyone standing underneath it who didn't ask for it. And to the night sky generally. A new peer reviewed study led by Miroslav Kochifai and Princeton astrophysicist Gaspar Bakos worked out exactly how bright one of these full scale 54 metre mirrors would actually look from the ground.

2:37 Their number about magnitude -16.7, roughly 4 magnitudes, which works out to about 40 times brighter than the full moon for anyone standing inside its roughly 3.4 mile beam. Avery: 40 times the full moon. That's not reading by moonlight bright. That's daylight. Anna: That's the point. Bacchus was making. His actual quote was that it would be worse than big cities like London for light pollution and that you would not see any stars if you were in the beam. And it's not just the direct beam either.

3:11 The study also modelled how sunlight scatters around the atmosphere around that brightest source, and found the skyglow stays measurably brighter for another 20 to 30 kilometres beyond the edge of the beam itself. Avery: So even people who aren't the target Anna: still get some of the glow right, and it compounds. Space.com's reporting on the study noted that if you had several hundred of these mirrors with overlapping beams, which is exactly what a 40,000 plus satellite constellation would eventually produce, the combined brightness could run up around, uh, 10,000 times the full moon in the overlap zones.

3:50 Avery: That feels like a genuinely different scale of problem to what we've talked about before with satellite constellations. Anna: It is a different problem and it's worth being precise about that difference. The Starlink style mega constellation complaints astronomers have been raising for years are mostly about individual satellites showing up as bright, moving streaks across long exposure telescope images. Annoying, sometimes ruining a specific observation, but a source of light, not a source of daylight.

4:21 This is different. It's purpose built to be as bright as possible, aimed deliberately at a patch of ground dark. Sky advocates like John Barentine have flagged separate concerns too. The effect on nocturnal wildlife that navigate and hunt by natural light cycles, not just on telescopes. Avery: What does the company say to all Anna: that Reflect Orbital's position? Is that the light stays contained to a defined target area, that beams can be shut off instantly if needed, and that they'll steer clear of observatories and sensitive habitats when scheduling illumination passes.

4:56 Whether that's enough to satisfy critics once there are tens of thousands of these things flying rather than one demo satellite, is very much the open question. And it's one regulators are going to have to keep answering as more of these filings show up. Avery: So this is really the opening chapter of a much bigger fight. Not the whole storey, exactly. Anna: That Arendelle Lun hasn't even flown yet. It's still targeted for later this year, but the FCC's already approved it. The astronomy community has already got peer reviewed numbers on exactly how bad the full scale version would be.

5:32 And the company's public ambition is 40,000 to 50,000 of these things within a decade. That's the shape of the next big fight between commercial space and the people who'd like to still see actual stars at night. Avery: A mirror in orbit and a genuinely unresolved argument underneath it. Anna: Watch this space. Sorry, couldn't resist that one. Avery: Sticking with things in orbit. Or in this case, things very much not in orbit anymore. Anna: Two Starship updates today, and they bookend each other nicely.

6:05 First ship 40, the upper stage that made that historic intact splashdown after Flight 13 back on July 24, has finally been loaded onto a heavy lift transport vessel in the Indian Ocean off Christmas island and is now on its way home to Starbase in South Texas. Avery: That's the one that had been floating around for weeks, right? Anna: That's the one towed further than originally expected, ending up sheltering off Christmas island for over three weeks before this loading happened. SpaceX says the trip back to Texas will take several months, but the reason it mattered enough to tow home at all is that ship 40 is the first starship upper stage ever to survive re entry and splashdown intact.

6:49 So engineers now get to physically inspect real heat shield samples and reentry damage, rather than just working from telemetry data that's already feeding into design changes on the next ships in line. Avery: And speaking of the next ship in line, that's flight 14, right? Anna: And here's the update. Some of what's circulating still says Flight 14 is targeting around August 28th today, but that number's gone stale. Internal SpaceX and FAA air traffic planning documents reported earlier this week put the actual no earlier than date at September 15th.

7:26 Ship 41 already finished its testing a single engine deorbit burn demo and a full six engine static fire in the last week or so. But booster 21 only just rolled out to the pad for its own static fire on Monday. And that's the item actually setting the pace now. Avery: So ship 40 finally gets home right as its sibling gears up to fly. Anna: Nice bit of symmetry, yes, and when Flight 14 does go it it's aiming for something Starship hasn't done yet, a full orbital flight. Deploying the newer larger Starlink V3 satellites.

8:00 Though the tower catch attempt for the returning ship is being pushed back again. Musk saying that's now probably in a few months. Rather than this flight, ship 41 will splash down in the ocean instead. Same as ship 40 did. Avery: One ship finally coming home by boat, the next one still a few weeks from even trying to fly. Anna: That's Starship in one sentence at the moment. Recovery and preparation happening in parallel on two completely different timescales. Avery: Alright, uh, from rockets to an actual planet, one with a pretty grim forecast.

8:35 Anna: Meet HD 176071 b, a newly characterised exoplanet about 335 light years away. Found by a team led by Sylvain Breton at Italy's National Institute for astrophysics. It's roughly 2 1/2 times Earth's width, about 8 1/2 times Earth's mass. And the modelling suggests something like half of that mass is water, half water. Avery: So an um, actual ocean world, not just a rocky planet with some water on it. Anna: That's the read. Though Ocean undersells how strange the conditions probably are because this planet orbits its star from just one and a half million miles out, completing a ah, full year in about 14 hours.

9:20 At that distance. We're not talking gentle blue oceans, we're talking a permanently baked tidally battered water world. Avery: How do you even find something like that? Doesn't the usual method needed to cross in front of its star Normally. Anna: Yes. The transit method. Watching starlight dim as a planet passes in front. This one was found a different way. Retton's team compared old Kepler space telescope data against newer observations from TESS and used the HAARPS N instrument on the Galileo National Telescope to measure tiny variations in sunlight reflected directly off the planet's surface.

9:59 Rather than waiting for a transit dip, it's a nice reminder that there's still real science to be squeezed out of years old archival data. If you bring a new technique to Avery: it and the living on borrowed time part, where does that come from? Anna: From exactly how close it's orbiting at 1 1/2 million miles. The tidal forces from star are extreme and the consensus from the team is that this planet is being slowly consumed. The kind of fate that waits for anything hugging a star this tightly. It won't happen on any timescale.

10:34 We'll be around to watch. But it's basically doomed by geometry the moment you look at the orbit. Avery: A uh, genuine ocean world discovered by a clever trick with old data and already on a slow path to being swallowed. Anna: Space has a way of finding new categories of beautiful but temporary last storey before skywatch. Avery: And um, it's the big one on everyone's launch calendar right now. Anna: The Nancy Grace Roman space telescope is two days from launch Sunday August 30, 7:26am, um, Eastern on a Falcon Heavy from Kennedy Space Centre.

11:08 Today is actually the launch readiness review happening as we record this. So we don't have that outcome yet. We'll be all over it once it lands. But we wanted to use today's slot on something. We haven't told you how close this mission came to never flying at all. Avery: I don't think I've Heard this part. Anna: Most people haven't, because it happened quietly in budget documents rather than headlines. Back in April last year, leaked draughts of the Trump administration's proposed 2026 NASA budget showed the largest funding cut in the agency's history on the table, uh, a 24% overall reduction, with science programmes alone facing a 50% cut.

11:51 And buried in that proposal, no funding Avery: for Roman for a mission that was already what most of the way built, Anna: 95% complete at that point, hardware built, tested most of the way through integration, and still facing a line in a federal budget proposal that would have effectively cancelled it. When the official skinny budget came out weeks later, it walked that back slightly. Roman got $156.6 million, less than half what it had the year before, but not zero. Still nowhere near enough certainty for a mission this far along.

12:27 Avery: So how did it end up two days from launch? Anna: Instead, Congress rejected the deeper cuts and restored NASA's funding to its previous levels. That's the part that actually saved it. But here's the detail we liked enough to build the whole segment around. Rather than just breathing a sigh of relief, Roman's own management team used the scare as motivation. They pulled the launch timeline forward from September to August 30, running double shifts and weekend work to get there, finishing eight months ahead of the original schedule and under budget.

13:00 Avery: That's a genuinely unusual reaction to nearly losing your funding. So sprint faster, not slower. Anna: Project manager Jamie Dunn put it about as plainly as you can. Delivering on your commitments means something, whatever you think about the politics around it. That's a team that came within a budget line of being cancelled and answered by launching nine months early. Once we've got the launch readiness review outcome and Sunday's launch itself, we'll bring you the full storey for today.

13:28 That's the part worth knowing going in Avery: a telescope that survived Washington before it even had to survive launch. Anna: Sometimes the hardest part of getting to space happens entirely on the ground. Avery: Alright, Skywatch time, quick win on both hemispheres tonight. Anna: Starting up north, that G2 geomagnetic storm watch NOAA issued earlier this week for Today, Friday the 28th is playing out right now as we speak. The combination of Tuesday's, um, M6.9 flare and a high speed solar wind stream reaching Earth's magnetosphere.

14:00 If you're at higher latitudes, northern tier US states, the uk, Scandinavia and similar tonight and into the weekend are worth stepping out for, weather permitting. Avery: And for us in the southern hemisphere, Anna: one more time, pretty much the same answer as it's been all week. A G2 level storm typically doesn't push the aurora Australis much past Tasmania on a good night. And there's nothing in this forecast suggesting it goes further than that this time either. Worth a glance at the southern horizon if you're somewhere dark, but we wouldn't build plans around it.

14:32 Avery: What's actually reliable for us down here tonight then? Anna: Um, Venus and Saturn. Same pair we've been pointing you to all week. Venus low in the west shortly after sunset. Unmistakably bright even with some light pollution around Saturn. Well placed and worth finding with binoculars once it's properly dark and tonight the Moon's essentially full. We watched most of the world's share of that partial lunar eclipse pass by in broad daylight here earlier today, so it'll be a bright night for the Moon itself, even if it's washing out some of the fainter stuff around it.

15:04 Avery: Venus at dusk, Saturn after dark, a full moon overhead and an aurora that's someone else's show. Anna: Tonight, a uh, properly full sky. Even the parts of it that aren't technically ours. And that's it for today's episode, series five, episode 179 and my quick recap. Avery: A uh, US startup's plan to beam sunlight down from orbit using giant mirrors has cleared its first FCC hurdle and the new peer reviewed study says the full scale version would be roughly 40 times brighter than the full Moon.

15:36 For anyone caught in the beam. Starship's ship 40 is finally on its way home from the Indian Ocean by ship while Flight 14 quietly slips to mid September, astronomers have found a hot water rich exoplanet slowly being consumed by its star, and the Roman Space Telescope is two days from launch after nearly losing its funding entirely last year and answering by launching nine months early. Anna: If you enjoyed the show, the best thing you can do is tell a friend. Leave us a rating wherever you listen and follow us.

16:11 Just search Astro AstroDailyPod Pod on Facebook, Instagram, TikTok x Tumblr and YouTube. Avery: And while you're there, head to astronomydaily.IO and sign up for our free daily newsletter, a summary of the latest space and astronomy news straight to your inbox, plus an email alert every time we post a new episode. Anna: We'll be back tomorrow with the weekend wrap. Until then, keep looking up clear skies everyone. See you then.

16:41 Avery: Mhm.

16:45 Anna: Love.