Black Hole
@konstructivizm
The James Webb telescope has discovered Jupiter-sized "planets" in space, free-floating and gravitationally unbound to any star

What has astonished scientists is that the planets are moving in pairs.

Astronomers are now trying to explain this phenomenon scientifically. They are inclined to believe that the objects were thrown out of their orbits due to gravitational disturbances.
NASA
6:10 AM · Apr 5, 2025

Rocket Diaries @rocket_diaries
·
6h
Webb just added a wild twist to our understanding of planetary formation—Jupiter-sized objects drifting through space in pairs, totally unbound to any star. Scientists think gravitational chaos may have ejected them, but why they’re paired up is still a mystery.

In For The Fun @InForTheFun_
·
13h
According to the International Astronomical Union, they are not planet. Because that's exactly how stupid their definition is. Defying something not based on its inherenet parameters like mass-radius (i.e. compactness), fusion etc, but on their orbital parameters. Go figure.

tigas Ars Tribunus Angusticlavius
21y
7,000
Subscriptor

SomewhereAroundBarstow said:
And that's as close as you're going to get an active astronaut to saying that what some people call the Deep State is actually where the heroes that keep everything from falling apart work.

What actually makes you a "steely-eyed missile man" isn't bravery, mojo, having XY chromosomes or white skin, it's to

sit in their cubicle for decades studying their systems, and knowing their systems front and back. And when there is no time to assess a situation and go and talk to people and ask, 'What do you think?' they know their system so well they come up with a plan on the fly

"Hey, this is a very precarious situation we're in." //

As it flew up toward the International Space Station last summer, the Starliner spacecraft lost four thrusters. A NASA astronaut, Butch Wilmore, had to take manual control of the vehicle. But as Starliner's thrusters failed, Wilmore lost the ability to move the spacecraft in the direction he wanted to go. //

Wilmore added that he felt pretty confident, in the aftermath of docking to the space station, that Starliner probably would not be their ride home.

Wilmore: "I was thinking, we might not come home in the spacecraft. We might not. And one of the first phone calls I made was to Vincent LaCourt, the ISS flight director, who was one of the ones that made the call about waiving the flight rule. I said, 'OK, what about this spacecraft, is it our safe haven?'"

It was unlikely to happen, but if some catastrophic space station emergency occurred while Wilmore and Williams were in orbit, what were they supposed to do? Should they retreat to Starliner for an emergency departure, or cram into one of the other vehicles on station, for which they did not have seats or spacesuits? LaCourt said they should use Starliner as a safe haven for the time being. Therein followed a long series of meetings and discussions about Starliner's suitability for flying crew back to Earth. Publicly, NASA and Boeing expressed confidence in Starliner's safe return with crew. But Williams and Wilmore, who had just made that harrowing ride, felt differently.

Wilmore: "I was very skeptical, just because of what we'd experienced. I just didn't see that we could make it. I was hopeful that we could, but it would've been really tough to get there, to where we could say, 'Yeah, we can come back.'"

So they did not.

Three weeks ago, NASA revealed that a shipping container protecting a Cygnus spacecraft sustained "damage" while traveling to the launch site in Florida.

Built by Northrop Grumman, Cygnus is one of two Western spacecraft currently capable of delivering food, water, experiments, and other supplies to the International Space Station. This particular Cygnus mission, NG-22, had been scheduled for June. As part of its statement in early March, the space agency said it was evaluating the NG-22 Cygnus cargo supply mission along with Northrop.

On Wednesday, after a query from Ars Technica, the space agency acknowledged that the Cygnus spacecraft designated for NG-22 is too damaged to fly, at least in the nearterm.

On Monday, the president posted a long statement on Truth Social that repeated this canard of the Biden administration, "They shamefully forgot about the Astronauts, because they considered it to be very embarrassing event for them—another thing I inherited from that group of incompetents."

Trump then went on to state that he and Musk had just sent up a SpaceX Dragon (which, in point of fact, launched last September) to rescue the crew. //

One of the common refrains about spaceflight for decades and decades is that it is nonpartisan.

That is, the Apollo Program brought the country together in the turbulent 1960s and helped make everyone feel good about the country. Pretty much ever since then, Republicans, Democrats, and independents have generally supported NASA and civil spaceflight. //

But if we're going to start lying about basic truths like the fate of Wilmore and Williams—and let's be real, the only purpose of this lie is to paint the Trump administration as saviors in comparison to the Biden administration—then space is not going to remain apolitical for all that long. And in the long run, that would be bad for NASA.

Let's also be clear that Musk and SpaceX are currently flying the only spacecraft in the Western world that is capable of reliably flying humans into orbit. Without Dragon, NASA would have been beholden to Russia for the last five years for human spaceflight. And when Boeing's Starliner had issues nine months ago en route to the International Space Station, NASA was fortunate to have the reliable Dragon program to turn to.

Yet perverting that good news story into some tawdry political gain cheapens SpaceX, NASA, and Wilmore and Williams. In this case, the truth was beautiful. When one American space company had a problem, another stepped in, and the heroic astronauts made it home safely with a perfect backdrop.

If only the story ended there.

Darkness fell over Mare Crisium, ending a daily dose of dazzling images from the Moon. //

Firefly Aerospace's Blue Ghost science station accomplished a lot on the Moon in the last two weeks. Among other things, its instruments drilled into the Moon's surface, tested an extraterrestrial vacuum cleaner, and showed that future missions could use GPS navigation signals to navigate on the lunar surface.

These are all important achievements, gathering data that could shed light on the Moon's formation and evolution, demonstrating new ways of collecting samples on other planets, and revealing the remarkable reach of the US military's GPS satellite network.

But the pièce de résistance for Firefly's first Moon mission might be the daily dose of imagery that streamed down from the Blue Ghost spacecraft. //

Dtiffster Ars Praefectus
9y
3,725
Subscriptor
TylerH said:
Given the amount of fuel needed to return to Earth, probably somewhere around the middle.

The prop to lift back off is at least 1.1 times the dry mass + up mass, but 78% of that is LOX which goes in the bottom tank. We don't know if the liftoff prop will just be in the tanks or in some kind of a really large header in the tank (as a boil off mitigation), but I would assume if there are headers they will be at or near the bottom of the of their respective tanks. Thus atleast 41% of the landed mass would be LOX and be very near the bottom. The legs and engine section will also be fairly substantial and very low. The methane for liftoff would be another 11% and only about a third of the way up the rocket. Much of the rest of the mass is tankage, but that center of mass is also probably no more than a third of the way up. The habitat section and equipment is high up, but it's less than 15% of that lift off mass. The CoM of the whole thing on landing/liftoff is probably only 25-30% up from the surface. It is much less tippy than your initial intuition would lead you to believe. //

https://www.youtube.com/watch?v=M2P-z_cXsOs

https://youtu.be/IpA9DORDkeE?si=oNmwnzJs6_UwzjPb

https://www.flickr.com/photos/fireflyspace/albums/72177720313239766/with/54395270843

Intuitive Machines announced on Friday morning that its Athena mission to the surface of the Moon, which landed on its side, has ended.

"With the direction of the Sun, the orientation of the solar panels, and extreme cold temperatures in the crater, Intuitive Machines does not expect Athena to recharge," the company said in a statement. "The mission has concluded and teams are continuing to assess the data collected throughout the mission."

Athena, a commercially developed lander, touched down on the lunar surface on Thursday at 11:28 am local time in Houston (17:28 UTC). The probe landed within 250 meters of its targeted landing site in the Mons Mouton region of the Moon. This is the southernmost location that any probe has landed on the Moon, within a few degrees of the lunar south pole. //

NASA has accepted that these commercial lunar missions are high-risk, high-reward. (Firefly's successful landing last weekend offers an example of high rewards). It is paying the companies, on average, $100 million or less per flight. This is a fraction of what NASA would pay through a traditional procurement program. The hope is that, after surviving initial failures, companies like Intuitive Machines will learn from their mistakes and open a low-cost, reliable pathway to the lunar surface. //

Fortunately, this is unlikely to be the end for the company. NASA has committed to a third and fourth mission on Intuitive Machines' lander, the next of which could come during the first quarter of 2026. NASA has also contracted with the company to build a small network of satellites around the Moon for communications and positioning services. So although the company's fortunes look dark today, they are not permanently shadowed like the craters on the Moon that NASA hopes to soon explore.

Q. There have been some pretty big geopolitical shifts since you went up there. What does it look like from your point of view?

Hague: Most of the time when I go over to the window, that's when I start thinking about the Earth below me. And I can tell you, in the time that I've been here, the time that I was here before six years ago, the view hasn't changed, and the thoughts that I eventually get to really haven't changed. I see Earth as a small, small orb that's in a pretty big black vastness of space. And there's a lot out there. There are more stars than you can count, but the world looks pretty small when it's in that perspective. And as you fly from continent to continent, you don't necessarily see all of those borders. And the lesson, or the realization that I always come away with is we have far more in common than we have in different, and those common things that we have bring us together. And if, if we're smart, those differences that we have are differences that we bring to teams like the International Space Station, and those differences make the team stronger.

"Every single thing was clockwork... We got some Moon dust on our boots." //

Firefly Aerospace became the first commercial company to make a picture-perfect landing on the Moon early Sunday, touching down on an ancient basaltic plain, named Mare Crisium, to fulfill a $101 million contract with NASA.

The lunar lander, called Blue Ghost, settled onto the Moon's surface at 2:34 am CST (3:34 am EST; 08:34 UTC). A few dozen engineers in Firefly's mission control room monitored real-time data streaming down from a quarter-million miles away.

The Dark Ars Tribunus Angusticlavius
8y
11,841
The lander's four shock-absorbing legs have some give, sort of like the crush zone of a car, according to Will Coogan, Firefly's chief engineer for the Blue Ghost lander. The legs have an aluminum honeycomb material inside, and they connect to bowl-shaped footpads with a ball-socket joint to give the spacecraft some flexibility in case it comes down on a slope or a rock.

That's basically a copy of the Apollo landers. Apollo had crushable aluminum honeycomb in the legs and bowl-shaped feet attached to the legs with ball joints. The statistical analysis was that Apollo's system had a 99.9% of not fully crushing the honeycomb as long as the landing velocity was below 4 feet per second horizontally and 7 feet per second vertically (1.22 m/s and 2.13 m/s). All of the landings were well under those velocities:

https://arstechnica.com/civis/attachments/1740667805423-png.103726/

NASA Technical Note TN D-6850 Apollo Experience Report - Lunar Module Landing Gear Subsystem by William F. Rogers (June 1972).

D-6850 Apollo Experience Report - Lunar Module Landing Gear Subsystem

https://ntrs.nasa.gov/api/citations/19730010151/downloads/19730010151.pdf. //

EarendilStar Wise, Aged Ars Veteran
8y
148
SkyeFire said:
Lunar conditions are brutal. Two weeks of brutal daylight (plus unfiltered solar radiation) followed by 2 weeks of total darkness. A few lunar probes have managed to survive the night and reboot once they got some sunlight again, but none of them survived more than a few day/night cycles. The thermal swings tend to destroy the electronics and power systems.

This entire bath and forth made me realize I don’t know how the temperature swings of the moon and Mars differ. I was reading thinking “How is this thermal swing different than Mars, a place we operate electronics for far more heat cycles than this?”.
Allow me to share what I found:

Commonly accepted average temps for Luna:
-180°C to 105°C
Mars:
-130°C to 22°C

That’s quite the difference!
Does anyone know why Mars nights are warmer? Is it mostly due to ground surface absorption of radiation, and not losing most of it until the next day cycle? The (limited) atmosphere retaining some heat? ///

Shorter nights on Mars

The math that makes refueling from the Moon appealing is pretty simple. "As a rule of thumb," write the authors of the new study on the topic, "rockets launched from Earth destined for [Earth-Moon Lagrange Point 1] must burn ~25 kg of propellant to transport one kg of payload, whereas rockets launched from the Moon to [Earth-Moon Lagrange Point 1] would burn only ~four kg of propellant to transport one kg of payload." Departing from the Earth-Moon Lagrange Point for locations deeper into the Solar System also requires less energy than leaving low-Earth orbit, meaning the fuel we get there is ultimately more useful, at least from an exploration perspective. //

the researchers decided to focus on isolating oxygen from a mineral called ilmenite, or FeTiO3. It's not the easiest way to get oxygen—iron oxides win out there—but it's well understood. Someone actually patented oxygen production from ilmenite back in the 1970s, and two hardware prototypes have been developed, one of which may be sent to the Moon on a future NASA mission.

The researchers propose a system that would harvest regolith, partly purify the ilmenite, then combine it with hydrogen at high temperatures, which would strip the oxygen out as water, leaving behind purified iron and titanium (both of which may be useful to have). The resulting water would then be split to feed the hydrogen back into the system, while the oxygen can be sent off for use in rockets.

(This wouldn't solve the issue of what that oxygen will ultimately oxidize to power a rocket. But oxygen is typically the heavier component of rocket fuel combinations—typically about 80 percent of the mass—and so, is the bigger challenge to get to a fuel depot.). //

The team found that almost all of the energy is consumed at three steps in the process: the high-temperature hydrogen reaction that produces water (55 percent), splitting the water afterward (38 percent), and converting the resulting oxygen to its liquid form (5 percent). The typical total usage, depending on factors like the concentration of ilmenite in the regolith, worked out to be about 24 kW-hr for each kilogram of liquid oxygen. //

Obviously, we can build larger arrays than that, but it boosts the amount of material that needs to be sent to the Moon from Earth. It may potentially make more sense to use nuclear power. While that would likely involve more infrastructure than solar arrays, it would allow the facilities to run around the clock, thus getting more production from everything else we've shipped from Earth.

Lunar exploration is undergoing a renaissance. Dozens of missions, organized by multiple space agencies—and increasingly by commercial companies—are set to visit the Moon by the end of this decade. Most of these will involve small robotic spacecraft, but NASA’s ambitious Artemis program aims to return humans to the lunar surface by the middle of the decade.

There are various reasons for all this activity, including geopolitical posturing and the search for lunar resources, such as water-ice at the lunar poles, which can be extracted and turned into hydrogen and oxygen propellant for rockets. However, science is also sure to be a major beneficiary.

The Moon still has much to tell us about the origin and evolution of the Solar System. It also has scientific value as a platform for observational astronomy. //

Several types of astronomy would benefit. The most obvious is radio astronomy, which can be conducted from the side of the Moon that always faces away from Earth—the far side.

The lunar far side is permanently shielded from the radio signals generated by humans on Earth. During the lunar night, it is also protected from the Sun. These characteristics make it probably the most “radio-quiet” location in the whole solar system, as no other planet or moon has a side that permanently faces away from the Earth. It is, therefore, ideally suited for radio astronomy. //

At that time, most of the matter in the Universe, excluding the mysterious dark matter, was in the form of neutral hydrogen atoms. These emit and absorb radiation with a characteristic wavelength of 21 cm. Radio astronomers have been using this property to study hydrogen clouds in our own galaxy—the Milky Way—since the 1950s.

Because the Universe is constantly expanding, the 21 cm signal generated by hydrogen in the early Universe has been shifted to much longer wavelengths. As a result, hydrogen from the cosmic “dark ages” will appear to us with wavelengths greater than 10 m. The lunar far side may be the only place where we can study this. //

Moreover, there are craters at the lunar poles that receive no sunlight. Telescopes that observe the Universe at infrared wavelengths are very sensitive to heat and therefore have to operate at low temperatures. JWST, for example, needs a huge sun shield to protect it from the sun’s rays. On the Moon, a natural crater rim could provide this shielding for free. //

But there is also a tension here: human activities on the lunar far side may create unwanted radio interference, and plans to extract water-ice from shadowed craters might make it difficult for those same craters to be used for astronomy. As my colleagues and I recently argued, we will need to ensure that lunar locations that are uniquely valuable for astronomy are protected in this new age of lunar exploration.

Since those initial reports were published in Western media, a small band of dedicated space trackers have been using open source data to try to identify precisely which space object fell into Kenya. So far, they have not been able to identify the rocket launch to which the large ring can be attributed.

Now, some space trackers believe the object may not have come from space at all. //

However, an anonymous X account using the handle DutchSpace, which despite the anonymity has provided reliable information about Ariane launch vehicles in the past, posted a thread that indicates this ring could not have been part of the SYLDA shell. With images and documentation, it seems clear that neither the diameter nor mass of the SYLDA component matches the ring found in Kenya.

Additionally, Arianespace officials told Le Parisien newspaper on Thursday that they do not believe the space debris was associated with the Ariane V rocket. Essentially, if the ring does not fit, you must acquit.

So what was it?

The agency tasked government labs, research institutions, and commercial companies to come up with better ideas to bring home the roughly 30 sealed sample tubes carried aboard the Perseverance rover. NASA deposited 10 sealed tubes on the surface of Mars a couple of years ago as insurance in case Perseverance dies before the arrival of a retrieval mission.

"We want to have the quickest, cheapest way to get these 30 samples back," Nelson said. //

"It has been more than two years since NASA paused work on MSR," the Planetary Society said. "It is time to commit to a path forward to ensure the return of the samples already being collected by the Perseverance rover.

"We urge the incoming Trump administration to expedite a decision on a path forward for this ambitious project, and for Congress to provide the funding necessary to ensure the return of these priceless samples from the Martian surface."
China says it is developing its own mission to bring Mars rocks back to Earth. Named Tianwen-3, the mission could launch as soon as 2028 and return samples to Earth by 2031. While NASA's plan would bring back carefully curated samples from an expansive environment that may have once harbored life, China's mission will scoop up rocks and soil near its landing site.

"They’re just going to have a mission to grab and go—go to a landing site of their choosing, grab a sample and go," Nelson said. "That does not give you a comprehensive look for the scientific community. So you cannot compare the two missions. Now, will people say that there’s a race? Of course, people will say that, but it’s two totally different missions."

Still, Nelson said he wants NASA to be first. He said he has not had detailed conversations with Trump's NASA transition team.

The first human mission to land on the Moon is one of the only NASA mission patches that does not include the names of the crew members, Neil Armstrong, Buzz Aldrin, and Michael Collins. This was a deliberate choice by the crew, who wanted the world to understand they were traveling to the Moon for all of humanity.

Another NASA astronaut, Jim Lovell, suggested the bald eagle could be the focus of the patch. Collins traced the eagle from a National Geographic children's magazine, and an olive branch was added as a symbol of the mission's peaceful intent.

The result is a clear symbol of the United States leading humanity to another world. It is simple and powerful. //

With the space shuttle, astronauts and patch artists had to get more creative because the vehicle flew so frequently—eventually launching 135 times. Some of my favorite patches from these flights came fairly early on in the program.

As it turns out, designing shuttle mission patches was a bonding exercise for crews after their assignments. Often one of the less experienced crew members would be given leadership of the project.

"During the Shuttle era, designing a mission emblem was one of the first tasks assigned to a newly formed crew of astronauts," Flag Research Quarterly reports. "Within NASA, creation of the patch design was considered to be an important team-building exercise. The crew understood that they were not just designing a patch to wear on their flight suits, but that they were also creating a symbol for everyone who was working on the flight."

In some cases the crews commissioned a well-known graphic designer or space artist to help them with their patch designs. More typically they worked with a graphic designer on staff at the Johnson Space Center to finalize the design. //

In recent years, some of the most creative patch designs have come from SpaceX and its crewed spaceflights aboard the Dragon vehicle. Because of the spacecraft's name, the missions have often played off the Dragon motif, making for some striking designs.

There is a dedicated community of patch collectors out there, and some of them were disappointed that SpaceX stopped designing patches for each individual Starlink mission a few years ago. However, I would say that buying two or three patches a week would have gotten pretty expensive, pretty fast—not to mention the challenge designers would face in making unique patches for each flight.

If you read this far and want to know my preference, I am not much of a patch collector, as much as I admire the effort and artistry that goes into each design. I have only ever bought one patch, the one designed for the Falcon 1 rocket's fourth flight. The patch isn't beautiful, but it's got some nice touches, including lights for both Kwajalein and Omelek islands, where the company launched its first rockets. Also, it was the first time the company included a shamrock on the patch, and that proved fortuitous, as the successful launch in 2008 saved the company. It has become a trademark of SpaceX patches ever since.

Almost no one ever writes about the Parker Solar Probe anymore.

Sure, the spacecraft got some attention when it launched. It is, after all, the fastest moving object that humans have ever built. At its maximum speed, goosed by the gravitational pull of the Sun, the probe reaches a velocity of 430,000 miles per hour, or more than one-sixth of 1 percent the speed of light. That kind of speed would get you from New York City to Tokyo in less than a minute. //

However, the smallish probe—it masses less than a metric ton, and its scientific payload is only about 110 pounds (50 kg)—is about to make its star turn. Quite literally. On Christmas Eve, the Parker Solar Probe will make its closest approach yet to the Sun. It will come within just 3.8 million miles (6.1 million km) of the solar surface, flying into the solar atmosphere for the first time.

Yeah, it's going to get pretty hot. Scientists estimate that the probe's heat shield will endure temperatures in excess of 2,500° Fahrenheit (1,371° C) on Christmas Eve, which is pretty much the polar opposite of the North Pole. //

I spoke with the chief of science at NASA, Nicky Fox, to understand why the probe is being tortured so. Before moving to NASA headquarters, Fox was the project scientist for the Parker Solar Probe, and she explained that scientists really want to understand the origins of the solar wind.

This is the stream of charged particles that emanate from the Sun's outermost layer, the corona. Scientists have been wondering about this particular mystery for longer than half a century, Fox explained.

"Quite simply, we want to find the birthplace of the solar wind," she said.

Way back in the 1950s, before we had satellites or spacecraft to measure the Sun's properties, Parker predicted the existence of this solar wind. The scientific community was pretty skeptical about this idea—many ridiculed Parker, in fact—until the Mariner 2 mission started measuring the solar wind in 1962.

As the scientific community began to embrace Parker's theory, they wanted to know more about the solar wind, which is such a fundamental constituent of the entire Solar System. Although the solar wind is invisible to the naked eye, when you see an aurora on Earth, that's the solar wind interacting with Earth's magnetosphere in a particularly violent way.

Only it is expensive to build a spacecraft that can get to the Sun. And really difficult, too.

Now, you might naively think that it's the easiest thing in the world to send a spacecraft to the Sun. After all, it's this big and massive object in the sky, and it's got a huge gravitational field. Things should want to go there because of this attraction, and you ought to be able to toss any old thing into the sky, and it will go toward the Sun. The problem is that you don't actually want your spacecraft to fly into the Sun or be going so fast that it passes the Sun and keeps moving. So you've got to have a pretty powerful rocket to get your spacecraft in just the right orbit. //

But you can't get around the fact that to observe the origin of the solar wind, you've got to get inside the corona. Fox explained that it's like trying to understand a forest by looking in from the outside. One actually needs to go into the forest and find a clearing. However, we can't really stay inside the forest very long—because it's on fire.

So, the Parker Solar Probe had to be robust enough to get near the Sun and then back into the coldness of space. Therein lies another challenge. The spacecraft is going from this incredibly hot environment into a cold one and then back again multiple times.

"If you think about just heating and cooling any kind of material, they either go brittle and crumble, or they may go like elastic with a continual change of property," Fox said. "Obviously, with a spacecraft like this, you can't have it making a major property change. You also need something that's lightweight, and you need something that's durable."

The science instruments had to be hardened as well. As the probe flies into the Sun there's an instrument known as a Faraday cup that hangs out to measure ion and electron fluxes from the solar wind. Unique technologies were needed. The cup itself is made from sheets of Titanium-Zirconium-Molybdenum, with a melting point of about 4,260° Fahrenheit (2,349° C). Another challenge came from the electronic wiring, as normal cables would melt. So, a team at the Smithsonian Astrophysical Observatory grew sapphire crystal tubes in which to suspend the wiring, and made the wires from niobium.

Does “Pix or it didn’t happen” apply to traveling to the edge of space on a balloon-lofted solar observatory? Yes, it absolutely does.

The breathtaking views on this page come courtesy of IRIS-2, a compact imaging package that creators [Ramón García], [Miguel Angel Gomez], [David Mayo], and [Aitor Conde] recently decided to release as open source hardware. It rode to the edge of space aboard Sunrise III, a balloon-borne solar observatory designed to study solar magnetic fields and atmospheric plasma flows.

Taking stock of spaceflight one-quarter of the way through the 2000s. //

2. Ingenuity flies on Mars
   Almost everyone reading this article remembers the seven minutes of terror associated with the landing of the Curiosity rover on Mars in 2012. A similar thing happened nine years later when the Perseverance rover landed on Mars (this time, with some amazing video of the dynamic experience). Yet as cool as these landings were, and as impressive as the capabilities of Curiosity and Perseverance are, a tiny payload named Ingenuity carried by Perseverance stole the show on Mars. //

3. Falcon Heavy launch, dual rocket landing
   By popular demand, this mission in February 2018 ranks in the top spot. The visuals were irresistible. The rocket launch itself was impressive, with the combination of 27 Merlin rocket engines generating a brightness that one almost had to look away from. Then the twin boosters separated and returned to Earth, landing like a pair of synchronized swimmers. Finally, there was the arresting view of a cherry red Tesla (and Starman) flying away from Earth in the general direction of Mars.

It was a spectacle that understandably captured the public’s attention. But the new rocket was more than a spectacle. By designing, building, and launching the Falcon Heavy, SpaceX demonstrated that a private company could independently fund and fly the largest and most powerful rocket in the world. This showed that commercial, heavy-lift rockets were possible. By providing competition to the Delta IV Heavy, the Falcon Heavy saved the US government billions. It's likely that the US government will never design and develop a rocket ever again.

Here's the math behind making a star-encompassing megastructure.

In 1960, visionary physicist Freeman Dyson proposed that an advanced alien civilization would someday quit fooling around with kindergarten-level stuff like wind turbines and nuclear reactors and finally go big, completely enclosing their home star to capture as much solar energy as they possibly could. They would then go on to use that enormous amount of energy to mine bitcoin, make funny videos on social media, delve into the deepest mysteries of the Universe, and enjoy the bounties of their energy-rich civilization.

But what if the alien civilization was… us? What if we decided to build a Dyson sphere around our sun? Could we do it? How much energy would it cost us to rearrange our solar system, and how long would it take to get our investment back? Before we put too much thought into whether humanity is capable of this amazing feat, even theoretically, we should decide if it’s worth the effort. Can we actually achieve a net gain in energy by building a Dyson sphere? //

Even if we were to coat the entire surface of the Earth in solar panels, we would still only capture less than a tenth of a billionth of all the energy our sun produces. Most of it just radiates uselessly into empty space. We’ll need to keep that energy from radiating away if we want to achieve Great Galactic Civilization status, so we need to do some slight remodeling. We don’t want just the surface of the Earth to capture solar energy; we want to spread the Earth out to capture more energy. //

For slimmer, meter-thick panels operating at 90 percent efficiency, the game totally changes. At 0.1 AU, the Earth would smear out a third of the sun, and we would get a return on our energy investment in around a year. As for Jupiter, we wouldn’t even have to go to 0.1 AU. At a distance about 30 percent further out than that, we could achieve the unimaginable: completely enclosing our sun. We would recoup our energy cost in only a few hundred years, and we could then possess the entirety of the sun’s output from then on. //

MichalH Smack-Fu Master, in training
4y
62

euknemarchon said:
I don't get it. Why wouldn't you use asteroid material?
The mass of all asteroids amounts to only 3% of the earth's moon. Not worth chasing them down, I'd guess. //

DCStone Ars Tribunus Militum
14y
2,313
"But [Jupiter]’s mostly gas; it only has about five Earth’s worth of rocky material (theoretically—we’re not sure) buried under thousands of kilometers of mostly useless gas. We'd have to unbind the whole dang thing, and then we don’t even get to use most of the mass of the planet."

Hmm. If we can imagine being able to unbind rocky planets, we can also imagine fusing the gas atmosphere of Jupiter to make usable material (think giant colliders). Jupiter has a mass of about 1.9 x 10^27 kg, of which ~5% is rocky core. We'd need to make some assumptions about the energy required to fuse the atmosphere into something usable (silicon and oxygen to make silicates?) and the efficiency of that process. Does it do enough to change the overall calculation though? //

Dark Jaguar Ars Tribunus Angusticlavius
9y
11,066
The bigger issue is the sphere wouldn't be gravitationally locked in place because the sun is cancelling it's own pull in every direction. Heck even Ringworld had to deal with this flaw in the sequel. That's why these days the futurists talking about enclosing the sun recommend "Dyson swarming" instead.

Edit: A little additional note. You can't really get the centrifugal force needed to generate artificial gravity across an entire sphere like you can with a ring. A swarm doesn't negate this. If you orbit fast enough to generate that artificial gravity, you're now leaving the sun behind. Enjoy drifting endlessly! No, rather each of these swarm objects are just going to have to rotate themselves decently fast.

A successful engine relight demonstration would pave the way for future Starships to ascend into stable, sustainable orbits. It's essential to test the Raptor engine's ability to reignite in space for a deorbit burn to steer Starship out of orbit toward an atmospheric reentry. //

The second change SpaceX will introduce on this test flight involves the vehicle's heat shield. These modifications will allow engineers to gather data before future attempts to return Starship to land at SpaceX's Starbase launch site in South Texas.

Perhaps as soon as next year, SpaceX wants to bring Starship back to Starbase to be caught by mechanical arms on the launch tower, similar to the way the company recovered the rocket's Super Heavy booster for the first time last month. Eventually, SpaceX aims to rapidly reuse Super Heavy boosters and Starships.

"The flight test will assess new secondary thermal protection materials and will have entire sections of heat shield tiles removed on either side of the ship in locations being studied for catch-enabling hardware on future vehicles," SpaceX wrote on its mission overview page.

SpaceX installed catch fittings on the Super Heavy booster to allow it to be captured by the launch tower's catch arms. The ship will need similar fittings jutting out from its heat shield.

"The ship also will intentionally fly at a higher angle of attack in the final phase of descent, purposefully stressing the limits of flap control to gain data on future landing profiles," SpaceX said. //

SpaceX seeks to fly Starships as many as 25 times next year, so cutting down the turnaround time between flights is fundamental to the company's plans. Making Starship capable of sustained orbital operations—something the in-space engine relight should enable—is a prerequisite for launching Starlink satellites or refueling Starships in orbit.