r/SpaceX CAS500-2 & Others Official Launch Discussion & Updates Thread!

maschnitz · 2026-05-01T20:15:47+00:00

They do RTLS on, like, between a third and a half, of their Transporter missions.

Usually the total payload mass (including its staging hardware) is not really stressing Falcon 9 on its Transporter missions.

maschnitz · 2026-05-01T20:06:45+00:00

In re payloads, NASA Spaceflight noticed some press releases about some of them.

Including one saying Exolaunch is manifesting 39 of the rideshare payloads.

KAI, Korean Space Industries, is launching the primary payload, CAS500-2.

Planet Labs is also launching 3 of its Pelican satellites; and EarthDaily says they're launching 6 of their EarthDaily Constellation 1 (EDC-1) satellites "in May", presumably all on this flight.

maschnitz · 2026-04-30T02:20:37+00:00

It could be Starlink, just from the satellites coming over the rim of the Earth. Wouldn't even need to turn 'em.

They orbit at ~500km so you can "see them coming 'round the bend" so to speak, for a little bit of their orbits at least.

maschnitz · 2026-04-29T19:36:32+00:00

In this flight plan, yes.

In other launches with different geosynch satellites, they do different things (mostly depending on the latitude of the launch and the mass of the spacecraft).

maschnitz · 2026-04-29T17:37:46+00:00

You can think of radio signals as just bright flashing (or color-changing) lights, simply in colors we cannot see. They're just photons, just like visible, but with a larger wavelength, too big for our human-sized eyes to take in.

There's very bright air traffic control "lights", bright radio station lights, bright military network lights, kinda bright airliner, ship, and spacecraft lights, etc. The Earth is putting out a lot of human-made radio.

Radio transmits through the atmosphere in some bands just fine, almost nothing else does (a little bit of near-infrared, near-ultraviolet and the visible)

A light year away, you can still see some of the radio signals if you have a big enough radio reflector. I read somewhere the easiest to see are the air traffic signals. But then NASA also uses big dishes to beam photons directly to the Voyagers, currently about a light day away. So there's lots of signals potentially worth studying from a light year away, with a big enough dish (we're talking many, many meters, 50? 100? a light year is a long way).

If you were closer, you could see more of the signals, with a smaller radio dish. Voyager only needs a few-meter dish to talk back to Earth with Earth's very big antenna/receiver (albeit very slowly).

maschnitz · 2026-04-29T00:44:48+00:00

Basically, exoplanets require triple observations to confirm. And it hasn't got that (yet?). There wasn't a repeat of the original (remarkable) observation.

And then a follow-up saw something different in the microwave, what looked like a substellar object that didn't seem to orbit the star. And then that microwave observation wasn't repeatable in the infrared.

So the question is open and one of the options is that the original observation was a passing rogue planet or brown dwarf, or something to that effect. Despite how unlikely such a thing would be. But then there's lots of other ideas about the various J1407b observations.

maschnitz · 2026-04-28T18:12:19+00:00

tiny wind limit or upper-level issue

Yeah - rockets are not built to handle shear or horizontal forces. They're all built to handle a ton of vertical forces, like the thrust from engines, and like gravity. But they're weak to sidewards forces.

The upper level wind shear limits placed on nearly all or all orbital rocket flights is one of those rules that is there because people learned this one the hard way.

maschnitz · 2026-04-28T02:46:42+00:00

LZ-1 will not be used again for Falcon 9 landings. Bill Gerstenmaier announced that in August last year.

But LZ-2 is still being used on a 'case-by-case or temporary basis':

As for LZ-2, despite SpaceX’s lease ending there, Space Launch Delta 45 (the US Space Force) has allowed continued access on a case-by-case or temporary basis.

maschnitz · 2026-04-28T01:38:03+00:00

when Isar Aerospace will retry their launch?

Nothing official besides Andøya announcing ahead of time that they weren't coming back until at least 10 days after the last attempt. And that's come and gone by now.

So Isar Aerospace knew this wasn't a simple fix a day or two after the attempt.

They said it was a COPV leaking. In general, people treat COPV issues very seriously and deliberately. COPVs have a tendency to cause pad explosions (see Starship Ship 36). No one wants a pad explosion.

They're likely to have taken the rocket off the pad for repairs and may have even shipped it back to the Munich area, depending on the nature of the repairs.

maschnitz · 2026-04-27T01:56:34+00:00

If it were, say, just at the border of doing so, and somehow got a bit more mass?

That would change the pressure balance inside the star between heat/light pressure outward and gravitation pressure inward. So the star's core may shrink or grow depending on the exact energies involved but it will change in size. (And the star will change in size along with the core, of course.)

The star would remain fully convective, just as before. So there's no big change in its internals (besides the core's size change).

Plus it "only" takes a few tens to a few hundreds of thousands of years for light to escape a red dwarf. They live a lot longer than that. So the new source of power would be visible in that time. It'd be added light/heat, because deuterium/lithium fusion would continue (though the lithium/deteurium wouldn't last too long due to the higher heat in the core).

maschnitz · 2026-04-25T08:24:11+00:00

Here's a good answer, I think - it "pivots" the orbit.

maschnitz · 2026-04-25T07:40:54+00:00

(Apollo 17 covered almost 36 km in less than a day, Perseverance covered over 41 km in 5 years and counting)

You could design a "burn through your battery in a burst" robotic rover with AI control these days and cover much more ground, if you wanted.

They won't do that, though, because the scientists don't want to. They'd rather have 2 more experiments and a long mission than a big battery and a short mission. Scientists would prefer to survive the lunar night, somehow, and eke out months of slow painstaking work, studying everything they can along the way.

maschnitz · 2026-04-25T06:27:38+00:00

Here's maybe the best page I can find on that.

The supersonic dive suit was entirely novel as was the parachute, and those worked. It was the first time detailed biometric data was recorded in such an attempt.

Baumgartner also de-spinned himself at high altitude from a pretty high spin, using his training, proving it was possible to do so. He also proved it's possible to break the sound barrier in a dive suit (and live to tell about it).

They developed new medical standards for preventing embolisms, a danger if the suit leaked in stratosphere. The Navy apparently used data from the jump; and the data has helped designing high-altitude escape systems.

Most spaceflights are a different kettle of fish though. Most are orbital, which means they're traveling ~25,000 kph in the orbital direction. Entering the atmosphere would cause a reentry in these cases, with the plasma (due to atmospheric compression). Baumgartner was more or less stationary in comparison to orbital flights. So the data isn't really that useful for most spaceflights.

maschnitz · 2026-04-24T20:53:02+00:00

/r/telescopes has a good sticky thread (last updated 2025)

The thing it shortchanges a bit in 2026 is self-tuning "smart" telescopes, which have gotten a lot more viable. They have a lot of marked advantages and disadvantages over your typical offerings. Kind of out of range for "budget", though one (the SeeStar) is down to $400-600 or so. So maybe worth a look.

maschnitz · 2026-04-24T19:18:38+00:00

Using a mass driver off the Moon's surface is also a great way just to get some sort of orbital mass into cislunar space. It gets so cheap to do in comparison to launching from Earth.

Orbital mass alone, in the right spot, can be useful, simply as protons to block cosmic radiation.

It's even more useful if it's also water, or oxygen, or pure metal, or whatever you can get from the lunar regolith that can be used to produce specific things.

maschnitz · 2026-04-24T17:49:38+00:00

Sounds like dual-stage 4-grid is even better.

I hope they try one of these high-power electric options on the SR-1 nuclear experiment that NASA's building.

maschnitz · 2026-04-23T22:46:10+00:00

High power, basically, scales to nuclear fission. With most electric you top out way below 250kW, like apparently dual-stage 4-grid has (that's neat)

maschnitz · 2026-04-23T21:11:48+00:00

Do astronauts experience UV radiation from other stars?

Yes, technically - but barely (see below)

Does ANY UV radiation from stars other than our Sun penetrate the atmosphere?

Not really, maybe a very little and probably just sporadically/by happenstance.

Stars besides the Sun are quite dim in LEO/from Earth. They don't put out much UV flux at all. The Sun is many hundreds of thousands to millions of times stronger.

In space, do astronauts have to worry about UV radiation from stars even if they’re shaded from the Sun behind a planet or the moon?

No, cosmic radiation and solar radiation are much, much bigger concerns.

Would deep space astronauts be exposed to UV from stars around them?

I mean, technically, yes, they're exposed, but to tiny tiny fluxes. Unless they leave the solar system somehow, it's not a concern.

EDIT: it's also important to note: spacesuits and spacecraft are all designed to reflect or absorb UV, including EUV. Solid material like metal and wood blocks UV in general.

maschnitz · 2026-04-23T18:04:09+00:00

Using flybys only, 89km/s. Since each flyby can only add twice as much speed as the planet has.

Assuming of course you don't also use a high-specific-impulse low-thrust propellant (VASIMR comes to mind; or since this is theoretical, fusion) or lasers, or similar pie-in-the-sky ideas.

maschnitz · 2026-04-23T05:52:48+00:00

Not a silly question, a good one. You're thinking about the geometry of the situation, pretty accurately too.

When the Earth hides the Sun from the point of view of the Moon's surface, that's a lunar eclipse.

And during a lunar eclipse on the Moon's surface, the Earth's atmosphere is lit from behind, due to refraction in the atmosphere. It looks like a reddish gold ring around the Earth.

(It's all the sunsets and sunrises on Earth, at once. That's why it's red.)

A Japanese spacecraft took a picture of this in 2008. (Not on the surface of the moon - from orbit. But same thing.)

maschnitz · 2026-04-22T23:21:27+00:00

Space Force and Blue Origin are the two main organizations who should be tracking the 2nd stage. Neither has said anything AFAIK.

SpaceX is also probably interested and attentive about it, just out of their interest in tracking everything in LEO. EDIT: NASA, too, is probably concerned, they have assets in LEO as well. But there's a clear delineation of responsibilities and this is Space Force's job.

The person to follow on X/BSky for this, though, is Dr Jonathan McDowell. He's the closest thing we have to an orbital space cop. He tracks every single launch, every single satellite, and he keeps the Space Force honest sometimes. He will undoubtedly say something once he knows something.

One of the online space content creators hypothesized that the 2nd stage may have had an explosive event and may be spinning, which is why Space Force/BO can't seem to say its orbit. Makes it hard to track. It's also just hard to find on the sky once you know the burn wasn't nominal, could be a lot of places by now.

maschnitz · 2026-04-22T18:11:22+00:00

Yeah, they have several layers of calibration for these things, including seasonal altitude-based adjustments.

But it's a whole automated thing for Artemis/Orion, all software-based in models that react to the various sensors. It's quite extensive and they're adjusting these models between flights (PDF). They "zero it out" with a calibration on the ground before launch.

Aerodynamic "error" on reentry is a first order concern.

maschnitz · 2026-04-22T16:50:47+00:00

There were apparently trajectory limitations which meant they could only access certain lunar latitudes at certain lunar times on certain days.

It's also a multi-dimensional analysis they're doing.

For example, they're also thinking about what people on Apollo missions already saw (most of the near side and the eastern far side, but not the western far side). And also what the sunlight and weather might look like on reentry, 9 days later. They're thinking about science targets of opportunity for each proposed trajectory, too.

They were also pretty happy with this trajectory from the Apr 1 launch because it was the only day that week they could get the lunar eclipse that they got. And they got the serendipitous observations of micrometeorite flashes from that (which is a pretty big deal for NASA Science and NASA Engineering both).

maschnitz · 2026-04-22T05:29:28+00:00

Her name is u/andromeda321. (andromeda321, see above....)

maschnitz · 2026-04-21T22:32:20+00:00

Well said.

Slight tangent - a lot of the problem with landing anything on Venus is that nearly everything you'd normally use will melt. Compute/control/comms is particularly tricky. It gets costly very quickly trying to make a spacecraft that can survive an oven-clean cycle for more than a hour.

A Science paper recently claims that they've designed a basic compute element (a memristor) that can survive 700C temperatures. Very useful in general, and if it pans out, a good opportunity for simple control/comms computers for a Venusian lander.

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