The Space Thread

That Tesla is 1. not in Earth orbit, and if it takes place from something that's Mars cyclers, and 2. it's not a "frivolous project" but a test article that could as well have been a lump of rock as a mass simulator and then nobody would care about it. The only reason people notice because "OMG Elon Musk launched a Tesla into space!".

For that matter, what happens to spend upper stages? Are they being actively deorbited using remaining propellant or do they stay in LEO until they naturally deorbit?

It is a standard practice of launch providers to send up new rockets with dummy payloads. Usually they're mass simulators: a chunk of metal with the rough mass of a satellite. One of the Falcon 1 test flights used a wheel of cheese. Using a Tesla Roadster as the payload for the Falcon Heavy demo flight was a genius bit of marketing and posed no hazard to any other vehicles since it's in a solar orbit that won't come anywhere near hitting another astronomical body for at least millions of years.

Making a talking point out of that specific event is not an accident. It's carefully crafted to conflate responsible use of LEO with anti-capitalist/anti-billionaire rhetoric. "Don't trust those rich people; they'll send cars to space."

That Luxembourg guy may have done better to talk about all the old Russian rocket stages flying around, but of course he can't piss off Putin. Elon Musk is a nice, safe target that will earn him a lot of Progressive Points™.

As for management of orbital traffic, it's important to remember several things. First, the chance of an active satellite hitting another active satellite is almost zero: the amount of volume up there is truly enormous. Even with tens or hundreds of thousands in orbit, there's no reason to anticipate calamity as long as there are responsible actors involved.

The majority of threats come from the following, in no particular order:

• Defunct objects such as expended rocket stages and inoperable satellites.
• Debris, including fragments of rocket stages and satellites that have either exploded or collided with other objects.
• Micrometeorites, including naturally occurring ones and manmade ones like flecks of paint, nuts and bolts, and other objects too small to detect.

Many of those defunct objects are very old, dating to before we had good technology to deorbit them. Some of them will be up for decades longer, if not more. Deorbiting them safely is a big deal and something we really need to tackle if we want to keep Earth orbit clean. However, there are serious issues involved such as ownership. Russia won't look kindly if we grab their old rockets or satellites, just like the US wouldn't look kindly on Russia for doing the same to ours.

Edited by Fighteer on Dec 6th 2021 at 10:29:52 AM

x2

If Musk wanted to launch a rock into the Sun's orbit he would have launched a rock. Him using a Tesla was clearly intentional. Now, granted, the launch itself was a breakthrough, but let's not pretend that it wasn't also an advertising move.

Edited by Altris on Dec 6th 2021 at 7:32:09 AM

So we'd need something out of Planetes, though perhaps with robots to make things more cost-effective.

Oh, I see, that makes it much clearer. Yeah, that does seem like stealth anti-billionaire rhetoric, then.

Of course it was an advertising move, but it could easily have backfired. Musk remarked before the flight that he gave it a 50/50 chance of succeeding and he had nightmares of a gigantic explosion on the pad and a wheel bouncing forlornly down the road.

Half of his purpose in founding SpaceX was to bring attention to spaceflight: to make it exciting for people again. The Roadster was part of that. But the launch itself was not hazardous to any other spacecraft, so calling it out as an example is entirely performative.

Edited by Fighteer on Dec 6th 2021 at 10:35:20 AM

I admit that that visual would have made the failure almost worth it.

Edited by Redmess on Dec 6th 2021 at 4:39:24 PM

Of course, but if you advertise more successfully then your competitors, you need to be prepared to have more attention than them. The fate of being a celebrity, as it were. Coca-Cola also does not like all the associations it brings to mind, I bet.

I meant to reply to this...

The answer is: it depends. The farther you go back in time, the less there was any active attempt to deorbit old rocket stages since they didn't have the necessary performance or capabilities. In most cases they will passively deorbit in a few years anyway, but higher orbits take much longer for this to happen and correspondingly demand more performance of the stage so it has less margin to clean itself up.

For launch providers that do attempt to prevent their stages from becoming debris objects, any/all of the following may be done:

• Expend remaining propellant after the end of the mission to lower its orbit and reenter safely. Most modern rockets do this if possible, but it's not always.
• If deorbiting is not feasible due to the characteristics of the orbit or the performance of the stage, expend remaining propellant to put it into a "graveyard" orbit that is not likely to used by any other spacecraft.
• "Passivate" the stage by releasing all remaining propellant and discharging the batteries. This means there is no risk of it suddenly exploding after years in orbit.
• Provide precise trajectory data to tracking agencies so they can monitor the stage's location and ensure that any necessary avoidance maneuvers are performed.
• Minimize the release of secondary objects that become debris in and of themselves. Payload fairings are usually released in suborbital trajectories so they don't become debris, but one example of this is the tension rods that hold Starlink stacks on the second stage. SpaceX usually deploys them in low orbits that will decay in a few weeks, but sometimes needs to use higher orbits, like on rideshare missions.

There are proposed measures for the future as well, such as requiring all launchers to pay additional fees into a fund dedicated to cleaning up Earth orbit. There is no direct profit in doing this, so the incentives for corporations to actively engage in stewardship are small, and governments don't seem to be jumping over each other to fund such projects.

I will also shout out to ULA here, which is making plans to use expended Centaur upper stages as refueling depots for future vehicles, in much the same way as SpaceX will deploy Starship fuel depots.

Yeah, well. I'm fairly sure Musk is aware of that game, since he plays it so enthusiastically. It doesn't make what the Luxembourg guy said any more truthful.

Edited by Fighteer on Dec 6th 2021 at 11:18:27 AM

What I meant when I said "it would just as well be a rock", I meant from a technical perspective. For the sake of demonstrating that the rocket works, for the risks to people or other spacecraft, there is no difference at all. It doesn't make the launch any more frivolous.

Edit: various degrees of

Edited by petersohn on Dec 6th 2021 at 5:24:10 PM

There could be a question of how necessary such a dummy payload really is. After all, if it should explode in LEO, that would add to the debris.

It's an interesting point. Once a rocket reaches orbit, "exploding" is no longer a risk, at least not in the sense of a launch failure, and anything that happens prior to reaching orbit is by definition not going to remain there. If the rocket fails three minutes into flight, for example, everything is coming back down.

Anyway, if the dummy payload is not released from the upper stage, as in the case of Falcon 1, Falcon Heavy, Astra's Rocket 3, etc., then it wouldn't matter what it is because it shares the fate of the stage. It's not like they're going to release a giant rock to float around in orbit by itself. In most cases the final orbit is low enough that it won't threaten anything for long no matter what happens.

A mass simulator is not just a gimmick, anyway, but a necessary part of the mission. The point is to simulate the mass of an actual payload so that the test occurs under realistic conditions. It has to be there for the test to be considered accurate.

Edit: By the way, Astra's recent successful launch of its Rocket 3.3 sent the upper stage and its mass simulator into a 500 km near-polar orbit. That's not coming down for quite a few years, but European politicians aren't up in arms about it. I wonder why.

Edit 2: The worst case for the Falcon Heavy launch would have been for the upper stage to fail while in its parking orbit prior to the Mars injection burn. An explosion there would have made for a fairly nasty debris cloud, but the car would have made a miniscule contribution, certainly no more than any other mass simulator.

In fact, part of the mission was to leave the stage there for six hours to test its resilience against radiation in the upper atmosphere. The possibility of failure was built in and accounted for.

Edited by Fighteer on Dec 6th 2021 at 1:27:34 PM

NASA TV is broadcasting the selection announcement for the next class of astronauts. Ten candidates have been selected from a pool of twelve thousand applicants. The names are to be listed shortly. Edit: There is a dedicated livestream.

I can't keep up with the announcements. I'll post the full list when they're done. Diversity check: six men, four women, eight white, two non-white (could be seven:three).

Bill Nelson introduces this class as "the Artemis generation". Nice. One is a SpaceX medical engineer. Another is a female combat pilot. There are also two UAE astronaut candidates here who will train with the US candidates.

Ugh. It's mainly just an opportunity for various VIPs to give speeches and receive applause. Edit: Never mind, the candidates are getting to speak.

Here's the official list:

• Nichole Ayers, 32, major, U.S. Air Force, first-ever female combat pilot of the F-22 Raptor, applied mathematics
• Marcos Berríos, 37, major, U.S. Air Force, pilot, aerospace engineering
• Christina Birch, 35, track cyclist on U.S. National Team, bioengineering
• Deniz Burnham, 36, lieutenant, U.S. Navy, chemical and mechanical engineering
• Luke Delaney, 42, major, retired, U.S. Marine Corps, research pilot
• Andre Douglas, 35, U.S. Coast Guard, robotics and systems engineering
• Jack Hathaway, 39, commander, U.S. Navy, distinguished aviator and test pilot
• Anil Menon, 45, lieutenant colonel, U.S. Air Force, USAF and SpaceX flight surgeon
• Christopher Williams, 38, medical physicist and specialist in radiation therapy
• Jessica Wittner, 38, lieutenant commander, U.S. Navy, pilot, aerospace engineering

A side-note: Anil Menon featured prominently in the TIME / Netflix Countdown documentary as the flight surgeon for the Inspiration4 mission. He absolutely knows what he is doing and couldn't be a better choice for an astronaut. He's certainly trained enough of them!

Edited by Fighteer on Dec 6th 2021 at 3:36:55 PM

Might have been posted in this thread elsewhere in the past if this is older news than I realize, but it's the first I've heard of it: scientists at the Limitless Space Institute claim to have successfully, albeit briefly, generated a small but fully-functional "warp bubble".

This is a key component of the (in)famous Alcubierre Drive proposed in the 90s as a (relatively) practical method of accelerating beyond the speed of light - the main problem with the idea, as I understand it, has always been the issue of generating the theorized "warp bubble" (yes, he deliberately stole the term from Star Trek), since for a long time our understanding has been that it would require an ungodly amount of exotic matter with negative mass, more than humanity could ever theoretically produce.

From what I understand breakthroughs in our understanding of physics over the last couple decades have led to the re-evaluation of the initial figures, with people thinking it might be possible with significantly less exotic matter, albeit still more than is currently within our reach. It seems like this serves as proof-of-concept for that? Like, "our existing technology can't generate one large enough to be practical, but it can generate one"?

Edited by Dirtyblue929 on Dec 6th 2021 at 6:43:34 AM

I saw that on Twitter but more knowledgeable respondents than me were not sure that the publication is reputable enough to cite, at least not without some peer review.

ULA's STP-3 mission aboard an Atlas V 551 rocket is currently go for launch at 09:04 UTC (4:04 AM EST) tonight (or tomorrow depending on where you are) from SLC-41 at Cape Canaveral, Florida. Coverage will be provided by ULA and NASA.

Payloads include:

• STPSat-6 for the National Nuclear Security Administration's Space and Atmospheric Burst Reporting System
• NASA's Laser Communications Relay Demonstration, which is integrated into STPSat-6
• Six secondary payloads for the U.S. Air Force.

NASA has an interest in this flight because of that demonstrator, which is intended to test the ability to use lasers to transmit data between Earth and geostationary orbit. Lasers stand to offer massively increased throughput over radio signals, especially at very long distances. You might remember that SpaceX is also doing this with its Starlink satellites, although those lasers will be operating at much shorter range.

The rocket is the second most powerful variant of Atlas V that ULA has to offer and the most powerful in actual use. ^note (There is a hypothetical 552 configuration that has never flown.) The 551 designation means that it has five GEM-63 solid rocket boosters, uses a 5-meter diameter payload fairing, and has a single-engine Centaur upper stage. This fairing is so large that it attaches to the core stage, with the Centaur encapsulated within. The core stage uses a Russian-made RD-180 engine with a dual-combustion-chamber design burning kerolox, and the Centaur stage uses an RL10C-1 engine burning hydrolox. Centaur remains to this day the most efficient upper stage ever developed.

The STP-3 mission was originally supposed to launch in 2020. Most recently, the schedule slipped by a couple of days due to ground equipment issues. I will be asleep when this launches and will provide an update after I get up.

On deck is another space tourism mission from Russia, Soyuz MS-20, with Japanese billionaire Yusaku Maezawa aboard, scheduled for Wednesday at 07:38 UTC — also one that I'll skip.

Edited by Fighteer on Dec 7th 2021 at 7:55:08 AM

Here's an open access article on the issue which however says that it's a theoretical way to create a warp bubble geometry, not something tried-and-tested. I note it was cited only once and not necessarily approvingly.

Aren't those kinda warp bubbles possibly risky if they work? Like, you'd probably wanna be far away from the home planet before really trying them?

So this isn't a detection of an actual warp bubble but a prediction that one might happen under the circumstances observed in a Casimir test? The hype train rolls on, I see.

What, like they'd turn into self-sustaining black holes or something? No, there's zero chance of that happening. Without a source of negative (or below ambient) energy density to power the trailing end of the bubble they simply dissolve.

Liftoff of the ULA STP-3 mission occurred this morning at 10:19 UTC (5:19 AM EST) after an hour-long hold for upper-level winds. Live coverage ended shortly after the Centaur upper stage reached its parking orbit, with the burn to geostationary transfer orbit happening a few minutes ago. The second coast phase has begun and will last about five hours until the final Centaur burn to circularize the orbit.

It is rare for an Atlas V to launch all the way to GEO, as I understand it. Most payloads are deployed into a transfer orbit and use their own propellant to circularize at geostationary orbit.

Edited by Fighteer on Dec 7th 2021 at 7:57:29 AM

The James Webb Space Telescope has been loaded with propellant in preparation for its journey to space in just over two weeks.

Chinese firm Galactic Energy apparently launched last night as well, although there wasn't a firm date in the schedules that I saw. Its Ceres-1 rocket successfully made it to orbit for a second time, which is apparently a Chinese record.

Meanwhile, The Daily Mail continues its exemplary track record of journalism by describing our Sun as "the solar system's largest star". Wags noted that it is also the solar system's smallest star as well as the roundest and hottest.

I mean, it could be right in a few million years!

Ars Technica (Eric Berger): Concerned about SpaceX, France to accelerate reusable rocket plans

This development project remains mired in European space politics, which is mainly about providing jobs, not competing on efficiency or price. France, Germany, and Italy are all engaged in an intense competition within the EU for funding and aerospace jobs.

A number of small launch startups have risen in Europe over the past five years, but nothing that could reasonably expect to compete with Falcon 9 in terms of payload. They all operate in the 1-ton or less market, and France's move to build its own reusable small launcher may be an effort to stamp out this potential competition. However, France is also sponsoring its own private launch companies.

Eric Berger observes that none of these efforts are likely to be meaningfully competitive given that Starship will probably be in full operation long before any of them can even begin launching.

The Hubble Space Telescope team reports that all of the science instruments have been restored to full functionality after a loss of synchronization messages back in October.

Edited by Fighteer on Dec 7th 2021 at 10:51:15 AM

Aye, that kind of timeline would make more sense in the world of the Mountain Archipelago [this is how the fictional world I write is named], where climate change came down on the US space facilities during summer 2018 and threw them back by decades. Not in the real world.

[That said, what's the expected cost of this Maïa? A payload 15 times larger isn't as impressive if the cost is 15 times larger too]

I see no specific information about Maïa's price. It's probably too early to announce it. It doesn't even have a Wikipedia page.

It is a one-ton launcher, which as noted is much smaller than Falcon 9. The "reuse penalty" will likely be substantial, especially if it intends to land propulsively. If we look at current expendable launchers in that class, the going rates are five to ten times higher per kilogram than Falcon 9. It would take a miracle for it to be competitive on a price-per-kg basis with any medium-lift launcher.

In that one-ton class, the most obvious competitor would be the Firefly Alpha, an expendable vehicle with a listed price of $15 million for one ton of payload to LEO. This comes to $15,000/kg compared to the Falcon 9 at approximately $3,000/kg. We can also compare Italy's Vega rocket, which costs $37 million for a max payload of 1,430 kg (to polar orbit), or $25,874/kg.

In summary, Maïa isn't competing with Falcon 9 any more than a pizza delivery person is competing with Amazon Prime. What will kill it dead is if Starship can deliver 100-ton payloads to orbit for less than the current price of a one-ton launch vehicle. This would be comparable, in our analogy, to Amazon Prime adding a home pizza delivery service.

ULA reports that the STPSat-6 satellite has been released from the Centaur stage after completion of the circularization burn. Additional payloads will be released over the next hours.

Edited by Fighteer on Dec 7th 2021 at 11:54:58 AM

Well, more like: If Starship has 100 1-ton payloads available. Not all unused capacity can be cut from costs; main limitation of economies of scale in real life.

That said, pardon for asking the hypothetical questions, where would spacefaring be today if we had 100-ton-to-LEO reusable launchers in 2015?

SpaceX's plans to eventually make a Starship launch as low as $2M. I'm not sure they'll succeed in that, but if so, that will make every other rocket automatically obsolete. It would be cheaper to launch even a small satellite with a Starship than using any of the competitors.