While Rocketdyne’s ownership merry-go-round kept spinning, the company’s competitors pushed forward. SpaceX and Blue Origin, backed by wealthy owners, took a fresh approach to designing rockets. Apart from the technical innovations that led to reusable rockets, these newer companies emphasized vertical integration to cut costs and minimize reliance on outside supply chains. They wanted to design and build their own rocket engines and were not interested in outsourcing propulsion. Rocketdyne’s business was—and still is—entirely focused on selling ready-made engines to customers.

The launch startups that followed in the footsteps of SpaceX and Blue Origin have largely imitated their approach to insourcing. There are at least nine medium to large liquid-fueled rocket engines in production or in advanced development in the United States today, and just one of them is from the enterprise once known as Rocketdyne: the RS-25 engine used to power the core stage of NASA’s Space Launch System (SLS) rocket. //

The RS-25 engine, by far the largest in L3Harris’ portfolio and a former Rocketdyne product, is not part of the sale. The RS-25 was initially known as the Space Shuttle Main Engine and was designed for reusability. The expendable heavy-lift SLS rocket uses four of the engines, and NASA is burning through the 16 leftover shuttle-era RS-25 engines on the first four SLS flights for the agency’s Artemis Moon program. The second SLS flight is set to launch in the coming months on a mission carrying four astronauts beyond the Moon.

L3Harris will retain total ownership of the RS-25 program. The company has a contract with NASA to build new RS-25 engines for SLS flights beyond Artemis IV. But the new RS-25s will come at an expense of about $100 million per engine, significantly more than SpaceX sells an entire launch on a Falcon 9 rocket. The engine contract is structured as a cost-plus contract, with award and incentive fees paid by the government to L3Harris.

Looking west from Tucson, Arizona, USA one day last month, the sunset sky looked strange when it briefly lit up with the plume of a rocket launched from California a few minutes earlier. Appearing at times like a giant space fish, the impressive rocket launch from Vandenberg Air Force Base near Lompoc, California, was so noticeable because it was backlit by the setting Sun.

“It’s hard to describe how epic this comeback was after our first Falcon 9 launch failure.”

On Dec. 21, 2015, SpaceX launched the Orbcomm-2 mission on an upgraded version of its Falcon 9 rocket. That night, just days before Christmas, the company successfully landed the first stage for the first time. The story behind this remarkable achievement is nowhere more fully told than in the book Reentry, authored by Ars Technica Senior Space Editor Eric Berger and published in 2024. To mark the tenth anniversary, Ars is reprinting a slightly condensed chapter from the book that tells the inside story of this landing. The chapter begins in June 2015 with a tragedy, the disintegration of a Falcon 9 rocket carrying the CRS-7 cargo supply mission for NASA. It was the first time a Falcon 9 had been lost in flight.

normally butters Ars Praefectus
18y
5,285
ahsgdbeyb3 said:
I am curious about what role exactly he had here in the control room. Operators freezing up sounds like an understandable response, but also sounds like there was a lack of sims to prepare then for such events. The flight director would be the one who should keep them on focus, not a manager. I would actually keep such 'VIP' people out of the control room, they tend not to be able to offer much of use during an actual flight, so I'm wondering how SpaceX managed their presence here and what kind of access to the loops they were/are given?
SpaceX has a "responsible engineer" culture. The engineers who know the most about a system assume responsibility for that system and may eventually have a management role and/or represent that system on console in mission control. This philosophy extends to higher levels. The manager of the Dragon program is a responsible engineer wearing a manager hat, not an MBA. David Giger was responsible for Dragon as a whole, and that was the role he was playing when he reminded the team that Dragon is still alive and might still be saved.

This isn't how NASA works. This isn't how legacy NASA contractors work. For example, Boeing outsources Starliner mission control to NASA. Boeing trains NASA controllers and managers on how to operate Starliner, and they provide "back room" engineering support for the NASA controllers on console. I'll never forget the video from Mission Control Houston during the Starliner OFT-1 MET clock anomaly when the thrusters were firing like crazy immediately after separating from the launch vehicle. The NASA Flight Dynamics Officer was gesticulating wildly in an animated conversation facing the Flight Director, obviously unprepared for this scenario and probably not giving the Flight Director the answers he wanted to hear. I felt sorry for him.

The damage will therefore test the current leaders of Russia. How committed are they to the International Space Station partnership with NASA? Before, they were willing to play out the string to 2030 and the end of the station’s lifetime, but that required minimal investment in new capabilities. In fact, Russia recently cut the number of crewed Soyuz missions to the station from four every two years down to three, to save money. Now they must devote significant resources to the Soyuz program critical to the ISS.

“This is a real-life test of their resilience,” Jeff Manber, a senior Voyager official and former Nanoracks chief executive with long-time expertise in Russia’s space program, told Ars. “We are going to learn just how important the ISS is to leadership there.” //

The at least temporary loss of Site 31 will only place further pressure on SpaceX. The company currently flies NASA’s only operational crewed vehicle capable of reaching the space station, and the space agency recently announced that Boeing’s Starliner vehicle needs to fly an uncrewed mission before potentially carrying crew again. Moreover, due to rocket issues, SpaceX’s Falcon 9 vehicle is the only rocket currently available to launch both Dragon and Cygnus supply missions to the space station. For a time, SpaceX may also now be called upon to backstop Russia as well.

blackhawk887 Ars Tribunus Angusticlavius
9y
19,694
100% TNT equivalent is crazy. Even 25% is probably twice a reasonable figure. The FAA uses 14% for LOX/hydrogen and 10% for LOX/kerosene. Hydrogen is more than twice as energetic per mass of methane, and kerosene about 80% as energetic as methane.

LOX and liquid methane are miscible, unlike the other combinations, but there aren't any plausible scenarios where you'd get better mixing than a rocket falling back on the pad shortly after liftoff, which both kerolox and hydrolox are also perfectly capable of doing. //

mattlindn Ars Centurion
7y
231
NASA's current blast range evacuation area ranges from 3 to 4 miles as shown in the diagrams in this article (I measured it on google maps).

It's worth mentioning that the privately run Rocket Ranch down in South Texas where people can pay money to get closer to the Starship launches is only 3.9 miles from the launch site. The people who watch from the Mexico can get as close as 2.4 miles.

Where most people (including myself) watch(ed) from, South Padre Island, is almost exactly 5 miles away.

So yeah this seems kind of excessive. //

Jack56 Ars Scholae Palatinae
7y
672
For the nth time, a fuel-oxidiser explosion is not a detonation. It is a deflagration. They are far less violent. An intimate mixture of gaseous oxygen and methane can detonate but liquid methane and liquid oxygen cannot mix intimately - are not miscible - because methane is a solid at lox temperatures, especially the sub-cooled lox which Starship uses. A detonation takes place in under a millisecond. Deflagrations are fires. I’m not saying it wouldn’t be bad but comparisons with an energetically equivalent mass of TNT are way out of line. //

mattlindn Ars Centurion
7y
231
Jack56 said:

For the nth time, a fuel-oxidiser explosion is not a detonation. It is a deflagration. They are far less violent. An intimate mixture of gaseous oxygen and methane can detonate ....

Didn't think about this, but yes you're correct. The boiling point of Oxygen is 90.2 K and the melting point of Methane is 90.7 K. If you mix the two together, before any Methane can melt all the oxygen has to boil off. Though there should still be some local melting given the outside air temperatures are MUCH warmer than the liquid oxygen.

Though at the same time given the temperatures are so close together I don't think much Methane will freeze before an explosion happens. So maybe the point is moot? //

SpikeTheHobbitMage Ars Scholae Palatinae
3y
1,745
Person_Man said:

I have to imagine a fully fueled stack with optimal mixing for the biggest explosion would probably be the largest non nuclear explosion ever.

Most of Starship's propellant is oxygen. The full stack only carries 1030t of methane (330t on Ship, 700t on SuperHeavy). Methane also has a TNT equivalent of only 0.16. Using the omnicaluclator, I get 1030t of methane* = 164.8t of TNT. That doesn't even make the top 10 list.

*omnicalculator lists natural gas, which is mostly methane. //

blackhawk887 Ars Tribunus Angusticlavius
9y
19,694
mattlindn said:

Didn't think about this, but yes you're correct. The boiling point of Oxygen is 90.2 K and the melting point of Methane is 90.7 K. If you mix the two together, ...

Mixing with oxygen should depress the freezing point of methane. For example, if you take water at its freezing point, and mix it equally with alcohol that is itself, say, 10 degrees colder than the freezing point of water, the resulting mix will be well below 0 C but will not contain any frozen water.

Also, you can mix butane and water under a little pressure, even though at atmospheric pressure butane boils a half-degree below the freezing point of water. They aren't miscible, but that's just because of polarity - they are happy to both be liquids at the same temperature and a little pressure.

Methane and LOX are considered miscible and were even considered for monopropellants at various mix ratios. The mixture is reportedly a bit shock sensitive though. //

SpikeTheHobbitMage Ars Scholae Palatinae
3y
1,745

Mad Klingon said:
For the many debating using eminent domain to expand launch facilities, that would likely be the simple part of the issue. Most of that area is considered sensitive wildlife area and dealing with the current piles environmental regulations and paperwork could take decades for a major expansion. Look at all the grief SpaceX gets when they build on the relatively bland bit of Texas coast they are currently using. It would be much worse at the Florida site.

One of the great legacies of Apollo was we got a well built out area for launching stuff before most of the environmental legislation was passed.

One of the great legacies of Apollo was that the exclusion zone around Cape Canaveral preserved enough of the wetlands in good enough condition to become a protected nature reserve.

“Until we get that data from the testing that is ongoing and the analysis that needs to occur, we’re going to continue to treat any LOX-methane vehicle with 100 percent TNT blast equivalency, and have a maximized keep-out zone, simply from a public safety perspective,” Chatman said.

The data so far shows promising results. “We do expect that BDA to shrink,” he said. “We expect that to shrink based on some of the initial testing that has been done and the initial data reviews that have been done.”

That’s imperative, not just for Starship’s neighbors at the Cape Canaveral spaceport, but for SpaceX itself. The company forecasts a future in which it will launch Starships more often than the Falcon 9, requiring near-continuous operations at multiple launch pads. //

The Commercial Space Federation, a lobbying group, submitted written testimony to Congress in 2023 arguing the government should be using “existing industry data” to inform its understanding of the explosive potential of methane and liquid oxygen. That data, the federation said, suggests the government should set its TNT blast equivalency to no greater than 25 percent, a change that would greatly reduce the size of keep-out zones around launch pads. The organization’s members include prominent methane users SpaceX, Blue Origin, Relativity Space, and Stoke Space, all of which have launch sites at Cape Canaveral.

The government’s methalox testing plans were expected to cost at least $80 million, according to the Commercial Space Federation.

The concern among engineers is that liquid oxygen and methane are highly miscible, meaning they mix together easily, raising the risk of a “condensed phase detonation” with “significantly higher overpressures” than rockets with liquid hydrogen or kerosene fuels. Small-scale mixtures of liquid oxygen and liquified natural gas have “shown a broad detonable range with yields greater than that of TNT,” NASA wrote in 2023. //

SpaceX said it has conducted sub-scale methalox detonation tests “in close collaboration with NASA,” while also gathering data from full-scale Starship tests in Starbase, Texas, including information from test flights and from recent ground test failures. //

The company did not disclose the yield calculation, but it shared maps showing its proposed clear areas around the future Starship launch sites at Cape Canaveral and Kennedy Space Center. They are significantly smaller than the clear areas originally envisioned by the Space Force and NASA, but SpaceX says it uses “actual test data on explosive yield and include a conservative factor of safety.” //

Concerns as mundane as traffic jams are now enough of a factor to consider using automated scanners at vehicle inspection points and potentially adding a dedicated lane for slow-moving transporters carrying rocket boosters from one place to another across the launch base, according to Chatman. This is becoming more important as SpaceX, and now Blue Origin, routinely shuttle their reusable rockets from place to place. //

Space Force officials largely attribute the steep climb in launch rates at Cape Canaveral to the launch industry’s embrace of automated self-destruct mechanisms. These pyrotechnic devices have largely replaced manual flight termination systems, which require ground support from a larger team of range safety engineers, including radar operators and flight control officers with the authority to send a destruct command to the rocket if it flies off course. Now, that is all done autonomously on most US launch vehicles.

The Space Force mandated that launch companies using military spaceports switch to autonomous safety systems by October 1 2025, but military officials issued waivers for human-in-the-loop destruct devices to continue flying on United Launch Alliance’s Atlas V rocket, NASA’s Space Launch System, and the US Navy’s ballistic missile fleet. That means those launches will be more labor-intensive for the Space Force, but the Atlas V is nearing retirement, and the SLS and the Navy only occasionally appear on the Cape Canaveral launch schedule.

The first multi-spacecraft science mission to launch to Mars is now on its way, and catching a ride on the twin probes are the first kiwis to fly to the red planet. //

“Rocket Lab has a tradition of hiding kiwis in many areas of its design,” said Lindsay McLaurin, senior communications manager for space systems at Rocket Lab, in response to an inquiry from collectSPACE.com. “The birds have snuck onto our rockets and satellites since the beginning of the company, reflecting the New Zealand roots of the company and as a challenge among our designers and spacecraft builders.”

The birds, which are native to the island country in the southwestern Pacific Ocean, appear as graphics on twin plaques attached to Blue and Gold. The metal plates, which adorn one of the two solar panels on each probe, also feature the Rocket Lab logo, the company’s motto (“Non Sufficit Hic Orbis” or “This World Is Not Enough”), and a similar icon of a bald eagle.

“To represent our company’s global presence,” said McLaurin, referring to the American icon. //

GFKBill Ars Tribunus Militum
21y
2,658
Subscriptor
*pushes pedant glasses up nose"
As a Kiwi myself, I need to point out that the Maori language doesn't use the "s" to denote plurals, or even have a letter "s", so it's two kiwi, not two kiwis.

Also, go Rocket Lab!

winwaed Ars Scholae Palatinae
9y
711

GFKBill said:
Maori language doesn't use the "s" to denote plurals, or even have a letter "s", so it's two kiwi, not two kiwis.

So the plural of "sheep" is "heep"?

GFKBill Ars Tribunus Militum
21y
2,658
Subscriptor

winwaed said:
So the plural of "sheep" is "heep"?

Well, we do have heeps of them.

SiberX Ars Scholae Palatinae
15y
1,249
Subscriptor++

GFKBill said:
Well, we do have heeps of them.

We just went over this; heep of them.

Waiting in the darkness a few miles away from the launch pad, I glanced around at my surroundings before watching SpaceX’s Falcon 9 thunder into the sky. There were no throngs of space enthusiasts anxiously waiting for the rocket to light up the night. No line of photographers snapping photos. Just this reporter and two chipper retirees enjoying what a decade ago would have attracted far more attention.

Go to your local airport and you’ll probably find more people posted up at a plane-spotting park at the end of the runway. Still, a rocket launch is something special. On the same night that I watched the 94th launch of the year depart from Cape Canaveral, Orlando International Airport saw the same number of airplane departures in just three hours. //

The Falcon 9’s established failure rate is less than 1 percent, well short of any safety standard for commercial air travel but good enough to be the most successful orbital-class in history. Given the Falcon 9’s track record, SpaceX seems to have found a way to overcome the temptation for complacency. //

According to analyses by BryceTech, an engineering and space industry consulting firm, SpaceX has launched 86 percent of all the world’s payload mass over the 18 months from the beginning of 2024 through June 30 of this year.

That’s roughly 2.98 million kilograms of the approximately 3.46 million kilograms (3,281 of 3,819 tons) of satellite hardware and cargo that all the world’s rockets placed into orbit during that timeframe. //

But Starship’s arrival will come at the expense of the workhorse Falcon 9, which lacks the capacity to haul the next-gen Starlinks to orbit. “This year and next year I anticipate will be the highest Falcon launch rates that we will see,” said Stephanie Bednarek, SpaceX’s vice president of commercial sales, at an industry conference in July.

SpaceX is on pace for between 165 and 170 Falcon 9 launches this year, with 144 flights already in the books for 2025. Last year’s total for Falcon 9 and Falcon Heavy was 134 missions. SpaceX has not announced how many Falcon 9 and Falcon Heavy launches it plans for next year.

Starship is designed to be fully and rapidly reusable, eventually enabling multiple flights per day. But that’s still a long way off, and it’s unknown how many years it might take for Starship to surpass the Falcon 9’s proven launch tempo. //

Despite all of the newcomers, most satellite operators see a shortage of launch capacity on the commercial market. “The industry is likely to remain supply-constrained through the balance of the decade,” wrote Caleb Henry, director of research at the industry analysis firm Quilty Space. “That could pose a problem for some of the many large constellations on the horizon.”

United Launch Alliance’s Vulcan rocket, Rocket Lab’s Neutron, Stoke Space’s Nova, Relativity Space’s Terran R, and Firefly Aerospace and Northrop Grumman’s Eclipse are among the other rockets vying for a bite at the launch apple.

ESCAPADE’s path through space, relative to the Earth, has the peculiar shape of a kidney bean. In the world of astrodynamics, this is called a staging, or libration, orbit. It’s a way to keep the spacecraft on a stable trajectory to wait for the opportunity to go to Mars late next year.

“ESCAPADE has identified that this is the way that we want to fly, so we launch from Earth onto this kidney bean-shaped orbit,” said Jeff Parker, a mission designer from the Colorado-based company Advanced Space. “So, we can launch on virtually any day. What happens is that kidney bean just grows and shrinks based on how much time you need to spend in that orbit. So, we traverse that kidney bean and at the very end there’s a final little loop-the-loop that brings us down to Earth.”

That’s when the two ESCAPADE spacecraft, known as Blue and Gold, will pass a few hundred miles above our planet. At the right moment, on November 7 and 9 of next year, the satellites will fire their engines to set off for Mars.

An illustration of ESCAPADE’s trajectory to wait for the opportunity to go to Mars. Credit: UC-Berkeley
There are some tradeoffs with this unique staging orbit. It is riskier than the original plan of sending ESCAPADE straight to Mars. The satellites will be exposed to more radiation and will consume more of their fuel just to get to the red planet, eating into reserves originally set aside for science observations.

The satellites were built by Rocket Lab, which designed them with extra propulsion capacity in order to accommodate launches on a variety of different rockets. In the end, NASA “judged that the risk for the mission was acceptable, but it certainly is higher risk,” said Richard French, Rocket Lab’s vice president of business development and strategy.

The upside of the tradeoff is that it will demonstrate an “exciting and flexible way to get to Mars,” Lillis said. “In the future, if we’d like to send hundreds of spacecraft to Mars at once, it will be difficult to do that from just the launch pads we have on Earth within that month [of the interplanetary launch window]. We could potentially queue up spacecraft using the approach that ESCAPADE is pioneering.”

Two Falcon 9 rockets lifted off from spaceports in Florida and California on Sunday afternoon, adding 56 more satellites to SpaceX’s Starlink broadband network.

The second of these two launches—originating from Vandenberg Space Force Base, California—propelled SpaceX’s Starlink program past a notable milestone. With the satellites added to the constellation Sunday, the company has delivered more than 10,000 mass-produced Starlink spacecraft to low-Earth orbit.

The exact figure stands at 10,006 satellites, according to a tabulation by Jonathan McDowell, //

The Starlink network surpassed 7 million global subscribers in August, primarily beaming Internet connectivity to homes and businesses. SpaceX is now aggressively pushing to broaden its service direct to smartphones. //

SpaceX is decommissioning aging and obsolete Starlink satellites as the company adds to the fleet. The retired satellites reenter the atmosphere, where they’re designed to burn up without any debris reaching the ground. Taking into account all the reentries, here are McDowell’s numbers for the Starlink fleet as it stands Monday, October 20:

8,680 total Starlink satellites in orbit
8,664 functioning Starlink satellites in orbit (including newly launched satellites not yet operational)
7,448 Starlink satellites in operational orbit //

Sunday’s SpaceX launches weren’t just noteworthy for Starlink. The first of the two missions, departing from Florida’s Space Coast, marked the 31st launch of the company’s most-flown Falcon 9 booster. The rocket landed on SpaceX’s recovery ship in the Atlantic Ocean to be returned to Florida for a 32nd flight. //

SpaceX engineers are now certifying the Falcon 9 boosters for up to 40 flights apiece.

The season of records isn’t over. SpaceX is expected to set another one later this week. The company’s launch log for 2025 currently stands at 132 Falcon 9 missions, tying the total number of Falcon 9 flights last year. SpaceX also launched two flights of the more powerful Falcon Heavy in 2024, bringing the 2024 mark to 134 missions by the Falcon rocket family.

A new listing of the 50 most concerning pieces of space debris in low-Earth orbit is dominated by relics more than a quarter-century old, primarily dead rockets left to hurtle through space at the end of their missions. //

Russia and the Soviet Union lead the pack with 34 objects listed in McKnight's Top 50, followed by China with 10, the United States with three, Europe with two, and Japan with one. Russia's SL-16 and SL-8 rockets are the worst offenders, combining to take 30 of the Top 50 slots. //

The list published Friday is an update to a paper authored by McKnight in 2020. This year's list goes a step further by analyzing the overall effect on debris risk if some or all of the worst offenders were removed. If someone sent missions to retrieve all 50 of the objects, the overall debris-generating potential in low-Earth orbit would be reduced by 50 percent, according to McKnight. If just the Top 10 were removed, the risk would be cut by 30 percent. //

China, on the other hand, frequently abandons upper stages in orbit. China launched 21 of the 26 hazardous new rocket bodies over the last 21 months, each averaging more than 4 metric tons (8,800 pounds). Two more came from US launchers, one from Russia, one from India, and one from Iran. //

Since 2000, China has accumulated more dead rocket mass in long-lived orbits than the rest of the world combined, according to McKnight. "But now we're at a point where it's actually kind of accelerating in the last two years as these constellations are getting deployed."

Six decades have now passed since some of the most iconic Project Gemini spaceflights. The 60th anniversary of Gemini 4, when Ed White conducted the first US spacewalk, came in June. The next mission, Gemini 5, ended just two weeks ago, in 1965. These missions are now forgotten by most Americans, as most of the people alive during that time are now deceased.

However, during these early years of spaceflight, NASA engineers and astronauts cut their teeth on a variety of spaceflight firsts, flying a series of harrowing missions during which it seems a miracle that no one died.

Because the Gemini missions, as well as NASA's first human spaceflight program Mercury, yielded such amazing stories, I was thrilled to realize that a new book has recently been published—Gemini & Mercury Remastered—that brings them back to life in vivid color.

The book is a collection of 300 photographs from NASA's Mercury and Gemini programs during the 1960s, in which Andy Saunders has meticulously restored the images and then deeply researched their background to more fully tell the stories behind them. The end result is a beautiful and powerful reminder of just how brave America's first pioneers in space were. What follows is a lightly edited conversation with Saunders about how he developed the book and some of his favorite stories from it.

The space plane will also advance the development of a new navigation technology based on electromagnetic wave interference. The Space Force news release characterizes this as the "highest-performing quantum inertial sensor ever tested in space."

Boeing has previously tested a quantum inertial measurement unit, which detects rotation and acceleration using atom interferometry, on conventional aircraft. Now, an advanced version of the technology is being taken to space to demonstrate its viability. The goal of the in-space test is to demonstrate precise positioning, navigation, and timing in an environment where GPS services are not available.

"Bottom line: testing this tech will be helpful for navigation in contested environments where GPS may be degraded or denied," Saltzman said in a social media post Monday, describing the flight.

Quantum inertial sensors could also be used near the Moon, where there is no comparable GPS capability, or for exploration further into the Solar System. //

Albino_Boo Ars Praefectus
7y
8,162
The reason why GPS is provide correction in drift on the laser ring gyros on Trident D5 boats. The key thing, which understandably isn't in the public domain, is the drift on quantum gyros. The other thing which I would be interested in is how they keep it cool enough for quantum effect to be in place. That must give the gyro in space a finite life because you can't top up the Helium. //

Lexus Lunar Lorry Ars Praetorian
7y
572
Subscriptor++
Quantum inertial sensors could also be used near the Moon, where there is no comparable GPS capability, or for exploration further into the Solar System.
One advantage of accurate inertial sensors is that they can be used underwater by submarines. This will be useful for our inevitable upcoming war with the Europan Fish People. There will be no GPS (or other satellite navigation or points of reference) under the mile-thick ice sheets. //

dmsilev Ars Tribunus Angusticlavius
15y
6,364
Subscriptor
wagnerrp said:
Well it needs to be a superfluid.... That means just letting the helium boil off isn't even an option.
Atom interferometry doesn't need conventional cryogenics. It uses laser cooling to trap and manipulate the atoms, so the essential requirements are very stable and precise lasers and other optics that are compatible with all the rigors of launch and spaceflight. At the proof-of-concept level, that's been done before; things like laser-cooled Bose-Einstein Condensates have been demoed on ISS, but obviously going from that to a high-precision navigation instrument entailed a lot of engineering development.

SpaceX's next Starship rocket exploded during a ground test in South Texas late Wednesday, dealing another blow to a program already struggling to overcome three consecutive failures in recent months.

The late-night explosion at SpaceX's rocket development complex in Starbase, Texas, destroyed the bullet-shaped upper stage that was slated to launch on the next Starship test flight. The powerful blast set off fires around SpaceX's Massey's Test Site, located a few miles from the company's Starship factory and launch pads.

Live streaming video from NASASpaceflight.com and LabPadre—media organizations with cameras positioned around Starbase—showed the 15-story-tall rocket burst into flames shortly after 11:00 pm local time (12:00 am EDT; 04:00 UTC). Local residents as far as 30 miles away reported seeing and feeling the blast.

SpaceX confirmed the Starship, numbered Ship 36 in the company's inventory, "experienced a major anomaly" on a test stand as the vehicle prepared to ignite its six Raptor engines for a static fire test. These hold-down test-firings are typically one of the final milestones in a Starship launch campaign before SpaceX moves the rocket to the launch pad.

The explosion occurred as SpaceX finished up loading super-cold methane and liquid oxygen propellants into Starship in preparation for the static fire test. The company said the area around the test site was evacuated of all personnel, and everyone was safe and accounted for after the incident. Firefighters from the Brownsville Fire Department were dispatched to the scene.

Car companies aren't accustomed to making vehicles that can only be used once. //

An experimental reusable rocket developed by the research and development arm of Honda Motor Company flew to an altitude of nearly 900 feet Tuesday, then landed with pinpoint precision at the carmaker's test facility in northern Japan.

The accomplishment may not sound like much, but it's important to put it into perspective. Honda's hopper is the first prototype rocket outside of the United States and China to complete a flight of this kind, demonstrating vertical takeoff and vertical landing technology that could underpin development of a reusable launch vehicle.

While Tuesday's announcement by Honda was unexpected, the company has talked about rockets before. In 2021, Honda officials revealed they had been working on a rocket engine for at least two years. At the time, officials said a small satellite launch vehicle was part of Honda's roadmap.

The rocket Honda talked about in 2021 could put a payload of up to 1 metric ton into low-Earth orbit. It's not clear if Honda is still aiming for this sector of the launch market. Company officials then committed to supporting internal development work until about 2025 or 2026, when it would make a "go" or "no go" decision on whether to finish the project and field an operational rocket.

normally butters Ars Praefectus
18y
5,207
Control Group said:
Having never heard of Impulse before, I'd love an explainer of their engineering. What makes their system better at in-space maneuvering?
The previous answers are all good, but I'll add that there are historical reasons why liquid kick/deploy stages have seen little investment in the West until recently, whereas the Soviets developed stages like Fregat and Briz which are conceptually similar to Impulse's Mira.

The US invested heavily in upper stages like Centaur which solve the relatively difficult problem of a high-performance cryogenic stage capable of multiple in-flight restarts. Questionable plans to put Centaur inside the Space Shuttle payload bay were abandoned after the Challenger disaster and replaced with a couple of barely-adequate solid-propellant kick stages for payloads going beyond LEO.

The Europeans, meanwhile, took advantage of their near-equatorial launch site in French Guiana to develop launch vehicles optimized for GEO missions with upper stages inserting into GTO directly from the ascent burn, without requiring any restart. Ariane 5 literally doubled down on this concept of operations by specializing in dual-satellite GTO injection missions. In more modern times, Vega has a liquid kick stage, AVUM, but powered by a hypergolic engine of Soviet heritage which was until recently manufactured in Ukraine.

On the US-headquartered side, Rocket Lab's Electron requires a kick stage from their Photon product line for any orbital mission, once again largely to avoid the challenge of restarting cryogenic stages in microgravity. Firefly, in contrast, has developed a restartable second stage, and they are developing a line of orbital transfer stages based on lower-thrust electric propulsion.

So, Impulse Space just doesn't have much competition in this part of the world. Different approaches were taken to the design of expendable upper stages. But in a future with reusable upper stages that don't want to accelerate to higher energies than they need to, separate kick stages are increasingly compelling. Likewise, if military forces begin to see earth orbit as a more kinetic or dynamic combat theater, that would also encourage kick/transfer stage development, for better or worse. //

Chuckgineer Ars Centurion
10y
323
Subscriptor
Bruce Dunn said:
The Mira thrusters are undoubtably pressure fed. With hydrazine, pressure is provided by helium from composite overwrap pressure vessels through often trouble-prone valves. Impulse does not say how the Mira propellants are pressurized, but it is notable that they both have high vapor pressures at near ambient temperatures. I suspect that the propellants are self pressurized, eliminating the mass and complexity of helium pressurization. At 273 K, the vapor pressure of ethane is 2.4 MPa and that of nitrous oxide is 3.2 MPa.

Hi Bruce, the article above (Industry Update: Prevalance of Nitrous-Based In-Space Propellants) verifies your suspicion: "Nitrous and propylene are self-pressurizing and do not require pumps, pressurants or even propellant management devices."
https://www.dawnaerospace.com/latest-news/prevalence-of-nitrous-based-in-space-propellants

Jack56 Ars Scholae Palatinae
7y
607
julesverne said:
Upside:Engine bay leak issue, solved.
Downside:Booster exploded.
Payload bay doors balked.
Ship attitude control lost.
No data on payload deployment.
No data on engine relight on orbit.
No data on Ship reentry.
The list goes on.

I'm sure SpaceX will solve these issues. But the root causes of the failures may negatively affect max payload mass to orbit. And the cadence of failure is picking up. Reason: unknown. But losing key engineers can cause outsized problems. I have no info on this, but given the recent series of backslips, I wonder if any of the most creative thinkers may have jumped Ship(sorry) following Musk's "Roman Salute" and other scumbag actions. I sure as fuck wouldn't want to work for him, despite intense interest in the SpaceX vision.

The main problems have been propellant system & engine leaks. It's new engineering territory. The engine chamber pressure is ~300 bar. The preburners are at >600 bar (>9,000 psi). The turbopumps higher again than that. The wonder is that most things don’t leak. //

Erbium68 Wise, Aged Ars Veteran
3m
1,070
Subscriptor
DistinctivelyCanuck said:
What I'm finding fascinating about the current failure modes on the block two starship is that obviously spacex thought they had a full handle on these from block one: and so many "solved problems" have spiraled into challenging fixes.
Leak issues causing loss of control were obvious in the very first flight that made it to sub orbital: but resolved on the subsequent flights.
Vibration issues causing RUD's: quickly resolved in the very first flights and are back again.
The other interesting aspect: the ground burns at massey's that were designed to identify these failures aren't doing it at ground level. (remember that there was a ground burn test with a near ten minute burn with extensive throttling:
I think we can expect another couple of iterations of those long burn tests soon.

My limited experience in the field of engine development tells me that this is perfectly normal for such projects. The solved problems always come with unexpected caveats. Especially vibration.
An example from ship practice is early reduction gear failures in turbines. All sorts of things were considered, lubrication was improved and the things worked perfectly on long term dyno tests. And then broke up at sea even under good sailing conditions.
The cause was eventually traced to the vibrations from the props caused by interference from the rudders. It was difficult to fix, but fixes were found (flexible shafts, basically).
Despite being so well understood the problem recurs over and over again as new bearing, hull and rudder designs come into use.
There was also a major vibration problem that hit Luftwaffe fighters in WW2. Arguments about defective bearings, reduction gears etc. duly took place. It was eventually traced to the fact that the fuel being used by the test labs was better than that often used at the front, which was messing with spark plugs and causing misfires which resulted in the vibration.
In engines, whether piston, turbine or rocket, just about everything interacts in ways beyond the scope of computer modelling - because until the mechanism is identified, it can't be modelled.

More power, no moving parts: the quest to fly a rotating detonation engine

After decades of research, tests advance innovative engine for improved military effectors //

Rotating detonation engines have no moving parts and a unique design that makes them both lighter and more powerful than traditional engines. Here’s how they work.

Just 10 years ago, a mere thousand or so operational satellites may have orbited our planet, but there will be tens or even hundreds of thousands a decade from now.

Experts have been sounding alarm bells for years that Earth orbit is getting a bit too crowded. So how many satellites can we actually launch to space before it gets to be too much?

Jonathan McDowell is an astrophysicist and astronomer at the Harvard-Smithsonian Center for Astrophysics who studies super-energetic phenomena in the universe such as jet-emitting black holes in galactic centers. In recent years, however, McDowell has gained prominence for his work in a completely different field of space research. In his monthly digital circular called Jonathan's Space Report, McDowell tracks the growing number of satellite launches and the ballooning number of objects in Earth orbit.

The project started with an ambition to "provide a pedantic historical record of the space age," but has, in a way, become a chronicle of the environmental destruction of the near Earth environment. In his frequent media appearances, McDowell has been vocal about his views on the future of the increasingly overcrowded near-Earth space.

"It's going to be like an interstate highway, at rush hour in a snowstorm with everyone driving much too fast," he told Space.com when asked what the situation in orbit will be like if existing plans for satellite megaconstellations such as SpaceX's Starlink, OneWeb and Amazon Kuiper come to fruition. "Except that there are multiple interstate highways crossing each other with no stoplights." //

"There's good evidence that the number of minor collisions is already increasing significantly," McDowell said. "We're seeing debris from objects that shouldn't really be creating debris. They probably have been hit by something small, even if they carry on working afterwards."

While the larger debris fragments over 4 inches in size are regularly tracked, trajectories of the smaller pieces are mostly unknown, and the collisions they can cause come entirely without warning.

Debris experts, however, are most concerned about encounters between two large defunct bodies — dead satellites or used rocket stages. One such close approach, between a decades-old Russian rocket upper stage and a long-defunct Russian satellite, took place on Jan. 27. With neither object being able to maneuver, space traffic guards could only look on with their fingers crossed, hoping the two would miss each other. On this occasion, they did —by a mere 20 feet (6 meters). The incident, described as a close call "worst-case scenario," could have spawned thousands of dangerous debris fragments that would have stayed in orbit for centuries, threatening everything in their path. //

McDowell says that humankind is likely going to discover the natural capacity of near-Earth space "the hard way." Despite the pledges of megaconstellation operators, the astrophysicist doubts that things will remain manageable in the years ahead.

"Five or 10 years from now, we'll have somewhere between 20,000 and 100,000 satellites, and I am very skeptical that at the upper number of 100,000 things can be operated safely," McDowell sai