The Space Thread

Wouldn't hypergolics still work?

Gonna use hypergolics to kickstart a technological civilization? Good luck with that. Last time I checked, most of them are horribly toxic. Plus, by their nature, they are synthetic. Bit of a chicken-and-egg problem.

Every year or so, in the World Building subforum, someone asks about aquatic, technological civilizations and we go through this little song and dance.

Edited by Fighteer on Apr 23rd 2024 at 1:58:34 PM

Oh, hot damn. That near-collision between two satellites back in February that NASA was concerned about?

Turns out they missed each other by less than TEN METERS and neither had the means to change course.

Someone on that planet could kickstart a civilization by figuring out how to pressurize atmosphere in a container. Wouldn't look like our timeline, but would be very interesting.

Yah but how do you create the necessary enthalpy to begin with? To make a pressure seal you need rubber, plastic, or glass, and good luck getting any of those without fire.

Edited by Fighteer on Apr 23rd 2024 at 2:16:29 PM

Volcanic heat source.

Two halves of a hollowed out rock, each lip of which consists of concentric ridges which intersect in sawtooth fashion, with some amount of tree sap between the halves, should do it, to start with.

Need an opening for an air pump, and an exhaust outlet. The heat will diffuse through the stone, delivering useful energy.

Volcanoes are hot ^{[citation needed]} and dangerous ^{[citation needed]} . I suppose one could build a society around one, using the heat to do metalworking and such, while accepting that every so often everybody gets murdered...

Trivial details...

Can we move this out of the Space Thread, though? It has virtually nothing to do with the topic, other than the possibility of finding civilizations on low-oxygen worlds.

Edited by Fighteer on Apr 23rd 2024 at 2:24:16 PM

The point is that such a planet, with such a civilization, would nevertheless appear to our astronomers as a low oxygen planet, and thus a poor candidate for advanced civilization.

On a different note, looks like NASA solved the garbled communication problem with Voyager 1

Not at all. If it had an industrial civilization, it would necessarily pollute its atmosphere, and that we would be able to detect, oxygen or no.

Edit: Everybody be like, "Dude, what if you looked for X," and astronomers be like, "Wow, thanks for telling us how to do our jobs."

Posted about last page.

Edited by Fighteer on Apr 23rd 2024 at 2:45:15 PM

Oops, sorry, missed that in everything else that was being talked about.

We've got a super rare double-header launch tonight. Rocket Lab is launching its "Beginning Of The Swarm" mission for NASA, featuring a demonstration laser sail payload, at 22:15 UTC. Literally two minutes later, SpaceX will launch Starlink Group 6-53, which will, if successful, be its 300th consecutive total booster landing.

Watch Rocket Lab's mission here and SpaceX's here.

Edited by Fighteer on Apr 23rd 2024 at 8:00:25 AM

It'd be utterly spectacular to have two rockets launch simultaneously from different locations and catch each other on camera.

There have been many cases of rocket launches being observed from aircraft and from orbit. Not sure that one launch has ever imaged a second one; the collision avoidance rules would likely prevent it. Maybe Starship will change that.

As expected, the Falcon 9 mission was successful and the booster landed. Happy 300! Rocket Lab's Electron lifted off late but is now in its coast phase ahead of kick stage relight and payload deployment.

Next up is another Falcon 9 with the WorldView Legion 1 & 2 Earth-observation satellites. Liftoff is from Vandenberg at 18:30 UTC tomorrow.

According to data from OSHA, Space X's Brownsville, Texas facility has had a reported injury rate of 5.9 per 100 workers for 2023, which is worse than the 4.9 from 2022 and over 7 times the industry standard of 0.8.

Edited by tclittle on Apr 24th 2024 at 12:04:40 PM

I've seen this kind of reporting before, and I am not sure it's adequately distinguishing between types of work. SpaceX performs operations, manufacturing, maritime, and construction, plus several other things, and accident rates are wildly different across those fields.

Some reporting suggests that one in ten construction workers is injured annually, and if a majority of Brownsville workers are in that occupation, SpaceX's injury rates would actually be below the average. Similarly, maritime work is much more dangerous overall than the average.

I popped over to the OSHA site and I don't have time to sift through a 22 MB CSV file to see if it performs this additional categorization. But "space" is such a broad field that you can't obtain useful comparative data from it. A majority of NASA employees are desk workers, for example. Do they count?

The most comparable data I can see there would be for Hawthorne, which is the company's main production facility for Falcon 9 and Dragon, among other things. It's at 1.7 per 100 workers, which is twice the industry average. That could certainly be a cause for concern, but it's not "seven times".

Edited by Fighteer on Apr 26th 2024 at 10:49:31 AM

SaxaVord Spaceport UK

BBC: Shetland spaceport moves closer to first rocket launch

SaxaVord Spaceport in Shetland has been navigating a web of financial and regulatory issues on its path to performing the first vertical launches from the United Kingdom, and this week it received its "range license", which "will allow the company to control the sea and airspace during launch." It received its spaceport license last December, and expects to begin flight activities later this year.

According to the article, seven operators are preparing to launch from SaxaVord. First up is German-based Rocket Factory Augsburg with its RFA One. Scottish company Skyrora could be next with its Skyrora XL, and German company HyImpulse is hot on its heels.

These are all small launch vehicles with capacities of up to 1,300 kg. They aren't in competition with SpaceX or ULA, but rather with companies like Rocket Lab and Firefly, plus Italy's Avio. (Well, one could argue they are in competition with SpaceX, but we talked about that earlier.)

Artemis II

Lots of space news comes from conferences. Marcia Smith reports via X that NASA is "still trying to understand" the fundamental physics behind the accelerated degradation of the heat shield on the Orion capsule for Artemis I. Until this is solved, it calls into question the timeline for Artemis II, which will need a functional heat shield to protect its two human crew members.

French Guiana

European Spaceflight: New Rocket to Take Over Soyuz Site in French Guiana

Following the severing of ties between Europe and Russia, the Soyuz launch site at French Guiana is vacant. The French space agency (CNES), which now owns the site, is looking for a new tenant. The most likely candidate at the moment is MaiaSpace, an ArianeGroup subsidiary, which is targeting 2025 for the maiden flight of its first rocket.

Whoever is selected will need to perform their first launch from the French Guiana site by 2027, and vehicles must have reference payload capability of at least 1,500 kg.

Space Nukes

Ars Technica: Russia stands alone in vetoing UN resolution on nuclear weapons in space

This week, Russia vetoed a UN Security Council resolution that would have reaffirmed a ban on WMDs in orbit. This comes after leaked US intelligence reports suggesting that Russia is developing a nuclear anti-satellite weapon. The veto only adds support to this idea. China abstained, while thirteen nations voted for the resolution.

Starliner CFT-1

NASA Flight Test Readiness Review Concludes, Teleconference to Follow

Boeing's Starliner has passed a flight readiness review ahead of its scheduled May 6 launch, during which it will carry humans for the first time. A dress rehearsal will be conducted today. The final step will be a launch readiness review, shortly before liftoff.

NASA astronauts Butch Wilmore and Suni Williams will be aboard this flight, which is the final step to fully certify Starliner to begin operational missions.

Ariane 6

ESA posted that the core stage of the first operational Ariane 6 rocket has been moved into its launch position. The demo flight is scheduled NET June 2024.

Separately, European Spaceflight reports that ArianeGroup completed "the last hot firing test" of the Ariane 6 upper stage on April 15. Interestingly, ignition of the upper stage engine was "not required" during the alleged hot-fire test, which was designed to simulate off-nominal conditions.

Starship

Eric Berger reports on SpaceX's progress towards the next Starship flight test. Apparently the company is targeting "toward the end of May"... so not exactly six weeks. The third flight was considered "a great success" by NASA. Also in this reporting is that SpaceX will test Starship-to-Starship cryogenic propellant transfer in 2025, something required for flights to the Moon and Mars.

Launch Schedule

Data courtesy of Next Spaceflight.

• China's Shenzhou-18 mission was successful yesterday, carrying taikonauts Ye Guangfu, Li Cong and Li Guangsu to the Tiangong space station.
• SpaceX | Falcon 9 Block 5 | Galileo FOC FM25 & FM27 | Apr 28 00:34 UTC. This will be the first time that Galileo satellites have launched on a non-European rocket. I mentioned a while ago that ESA is paying a premium to SpaceX to allow its own security personnel on site to prevent the leak of any sensitive information about the payloads. I'm reading that the booster for this mission will be expended.
• SpaceX | Falcon 9 Block 5 | Starlink Group 6-54 | Apr 28 21:50 UTC

It looks like the WorldView Legion 1 & 2 mission has been delayed until May 1. Not sure if that's because of weather or other factors. We could see a Minotaur IV launch by the end of April, and both Virgin Galactic and Blue Origin have flights planned, but without fixed dates and times.

I am travelling this weekend so may not be able to post launch webcasts in advance.

Edited by Fighteer on Apr 26th 2024 at 12:16:07 PM

Here is more info on tonight’s Galileo satellite launch from Kennedy Space Center. I’m still traveling so forgive any awkwardness.

Liftoff is at 00:34 UTC (8:34 PM EDT). The Falcon 9 booster, B1060, will be making its twentieth launch but not landing, as it will be expended to deliver the payloads to their targeted medium Earth orbit.

I don’t see an official livestream from either SpaceX or ESA, but it should be available here shortly before liftoff.

What makes this mission remarkable is not just that Europe is sending a vital security mission on a US rocket, but that it’s on a previously flown booster. While ESA leadership may not object to reusability, the EU legislature and its industrial partner, ArianeGroup, have been massively hostile to the idea until extremely recently.

Edit: X broadcast (official), NASA Spaceflight (unofficial). Still looking for an ESA link.

This is probably going to be a short broadcast because the booster won't land and they won't be able to show second stage video. Propellant loading is underway as of T-35 minutes. Ground-level winds look pretty strong, though.

Updates: Weather is green for liftoff. Godspeed B1060 and Galileo.

Liftoff occurred on time. MECO and stage separation successful. Fairing separation confirmed. As noted, this was the second twentieth launch of a Falcon 9.

As expected, there will not be any further views of the stage or payload on stream. Mission success will be announced on X.

Edited by Fighteer on Apr 27th 2024 at 8:39:58 AM

I'll be on the road again tomorrow, but in addition to a Starlink mission, we're expecting the departure of the CRS-30 Cargo Dragon from the International Space Station at 17:05 UTC. In addition to returning science payloads to Earth, it will free up the zenith docking port so that Crew-8 can rotate to it (scheduled for April 30). Doing so will allow Starliner's CFT-1 to dock to the forward port after its scheduled launch on May 6.

Who Launched Galileo?

The European Union's @EU4Space account on X posted about the successful launch of two Galileo satellites yesterday. For some reason, it omitted the name of the company and rocket that performed that task, instead referring to "the launcher". ESA head Josef Aschbacher posted something very similar.

This got them resoundingly called out in the replies and quotes, and really showcases just how much of a national — nay, continental embarrassment the whole thing is. Europe has no usable LVs and so it had to go crawling to an American company to do the job. Worse, it was a company flying a reused booster, something the EU has politically shunned for years and that its industrial leadership have loudly complained about for undercutting them on pricing.

Must be a bitter pill to swallow, so they choked on it and decided to go full petty. This probably also explains why they didn't allow any views from the second stage, when this has not been a standard practice for other Galileo launches. Heck, there wasn't even the typical customer promo ad during the livestream.

Jesucristo and mon dieu, meine Freunde. Maybe we won't launch your satellites next time, except... well, the money's pretty nice.

SpaceX CRS-30

The CRS-30 Dragon spacecraft undocked from the ISS on time today at around 17:05 UTC and is on its way home. Splashdown is expected late on Monday.

Shenzhou 17

After the successful launch and docking of Shenzhou 18 last week, the Shenzhou 17 crew will depart the Tiangong space station soon — I'm not seeing an exact time on the app — and are expected to land in the Chinese desert on Tuesday.

Edited by Fighteer on Apr 28th 2024 at 4:55:43 AM

What's the highest percentage of the speed of light that seems plausible to actually reach?

I got thinking about this when i read about Breakthrough Starshot's 15-20% possibly getting a probe to Alpha Centauri in only 20-30 years.

Edited by Nukeli on Apr 29th 2024 at 10:33:40 PM

The answer to that question depends on quite a few different factors: the most obvious one is propulsion methods. There's a way to calculate the maximum practical delta-V for any propellant; I don't remember the exact equation but it's a factor of the velocity of the exhaust.

Assuming that "sci-fi" technology like black hole drives or warp drives is not attainable, the most efficient possible fuel for any rocket is antimatter. A vehicle powered by this can get to absurd velocities like 0.9 c or higher. There are many practical problems to contend with to make antimatter usable, starting with its cost, but it's the best we can currently expect to achieve.

The Breakthrough Starshot program that you refer to would use an array of gigawatt lasers to accelerate postcard-sized probes to between 10 and 20 percent of the speed of light so they can get to nearby star systems and send back data. Scaling that up to the size of a colony ship would be an enormous challenge, not least of which is that humans tend to get irritable when subjected to thousands of g of acceleration.

Other ideas like Orion drives and fusion drives powered by Bussard ramjets exist and could potentially get us to that 10 to 20 percent range as well.

The second limit is space itself, specifically the fact that what we think of as a vacuum is not perfectly empty. There are stray molecules of hydrogen, flecks of dust, and all sorts of high-energy particles out there, among other things.

When we send spacecraft out at a few dozen km/s, micrometeoroids and other collisions are a known, manageable problem. If we get to a significant fraction of the speed of light, like 10% or higher, those collisions become so energetic that they start to erode the leading surfaces and generate hard radiation that will make things seriously uncomfortable for anyone and anything inside.

Shielding against this is possible but increases the mass of the spacecraft, requiring stronger engines to propel it, and thus we get into a vicious cycle.

For all of the problems some people have with its story, the movie Passengers (2016) is an attempt to show what a trip to another solar system aboard a relativistic spacecraft might look like. The ship is equipped with what appears to be magnetic shielding against the interstellar medium, but it gets disabled by an energetic particle all the same.

Edited by Fighteer on Apr 29th 2024 at 10:18:49 AM

You mean specific impulse? It's exhaust velocity divided by gravitational acceleration