Q: What is the highest apogee of a satellite in Earth orbit they need to avoid? Ignore any satellites in Solar or lunar orbit.

A: There are over a hundred satellites in Molniya orbit, a few tens in Tundra orbit and a handful in really high earth orbits. The first two of those go above geostationary orbit; there are examples of the last with perigee of at least 375,000km. //

James Webb Space Telescope, at the Earth-Sun L2 point, is roundly a million miles from Earth, but still gravitationally bound to the Earth-Moon system.

Other than that, there are very few if any permanent satellites beyond the "graveyard orbits" used to park expired geostationary satellites. These are typically only a few hundred kilometers higher than geosynchronous, however, so roundly if they're well beyond the 24 hour orbital period, they'd be well clear of anything we put up intentionally and left there. //

Then there is stuff, mostly debris, that is more critical, because by nature those pieces are very fast, the orbit is not stable, so it changes a little every round and the kinetic energy would be able to penetrate any hull that is not specifically designed to withstand such impacts. For example, this debris of an Iridium satellite - at the time of writing at altitude ~366,000km and counting, spiralling outwards at 1km/s (the map does not mention a size or weight though. But it is big enough to be trackable obviously).

It's unlikely Boeing can fly all six of its Starliner missions before retirement of the ISS in 2030. //

Ten years ago next month, NASA announced that Boeing, one of the agency's most experienced contractors, won the lion's share of government money available to end the agency's sole reliance on Russia to ferry its astronauts to and from low-Earth orbit.

At the time, Boeing won $4.2 billion from NASA to complete the development of the Starliner spacecraft and fly a minimum of two, and potentially up to six, operational crew flights to rotate crews between Earth and the International Space Station (ISS). SpaceX won a $2.6 billion contract for essentially the same scope of work.

A decade later, the Starliner program finds itself at a crossroads after Boeing learned it will not complete the spacecraft's first Crew Flight Test with astronauts onboard. NASA formally decided Saturday that Butch Wilmore and Suni Williams, who launched on the Starliner capsule on June 5, will instead return to Earth in a SpaceX Crew Dragon spacecraft. Put simply, NASA isn't confident enough in Boeing's spacecraft after it suffered multiple thruster failures and helium leaks on the way to the ISS. //

On Saturday, senior NASA leaders decided it wasn't worth the risk. The two astronauts, who originally planned for an eight-day stay at the station, will now spend eight months on the orbiting research lab until they come back to Earth with SpaceX. //

So why did NASA and Boeing engineers reach different conclusions? "I think we’re looking at the data, and we view the data and the uncertainty that’s there differently than Boeing does," said Jim Free, NASA's associate administrator and the agency's most senior civil servant. "It’s not a matter of trust. It’s our technical expertise and our experience that we have to balance. We balance risk across everything, not just Starliner."

The people at the top of NASA's decision-making tree have either flown in space before or had front-row seats to the calamitous decision NASA made in 2003 to not seek more data on the condition of Space Shuttle Columbia's left wing after the impact of a block of foam from the shuttle's fuel tank during launch. //

Now, it seems that culture may truly have changed. With SpaceX's Dragon spacecraft available to give Wilmore and Williams a ride home, the decision was relatively straightforward. Ken Bowersox, head of NASA's space operations mission directorate, said the managers polled for their opinion all supported bringing the Starliner spacecraft back to Earth without anyone onboard.

However, NASA and Boeing need to answer for how the Starliner program got to this point. //

SpaceX, which NASA has tapped to rescue the Starliner crew, has now launched eight operational long-duration crew missions to the International Space Station to date, plus an initial piloted test flight of the Dragon spacecraft in 2020 and several more fully private human spaceflight missions. SpaceX has finished all of its work in its initial commercial crew contract with NASA and is now working off of an extended contract to carry the program through 2030, the planned retirement date for the ISS. //

Right now, the prime route is through SpaceX. NASA continues to fly one astronaut on each Russian Soyuz spacecraft in exchange for a seat for a Russian cosmonaut on each SpaceX crew mission. //

Assuming the investigation doesn't uncover any additional problems and NASA and Boeing return Starliner to flight with astronauts in 2026, there will not be enough time left in the space station's remaining life—as it stands today—for Starliner to fly all six of its contracted missions at a rate of one per year. It's difficult to imagine a scenario where NASA elects to fly astronauts to the space station exclusively on Starliner, given SpaceX's track record of success and the fact that NASA is already paying SpaceX for crew missions through the end of this decade.

Notably, NASA has only given Boeing the "Authority To Proceed" for three of the six potential operational Starliner missions. This milestone, known as ATP, is a decision point in contracting lingo where the customer—in this case, NASA—places a firm order for a deliverable. NASA has previously said it awards these task orders about two to three years prior to a mission's launch.

The commercial crew contracts are structured as Indefinite Delivery/Indefinite Quantity (IDIQ) agreements, where NASA can order individual missions from SpaceX and Boeing as needed. If SpaceX keeps performing well and the space station is actually decommissioned in 2030, it may turn out that NASA officials decide they just don't need more than three operational flights of Starliner. //

Lone Striker Smack-Fu Master, in training
7y
62

accdc said:
Thank you Stephen, and Eric, for your fantastic coverage of this issue.

Here’s what I (as a layman with little technical expertise) don’t get:

How does SpaceX make it look so easy, and Boeing make it look so, well, ridiculous?

SpaceX designs, manufactures and integrates most components themselves. In Boeing's case, the thruster manufacturer is Aerojet. In order to make changes or redesign the components, there is a huge bureaucratic barrier in place. They have to jump through extraordinary hoops, not only engineers but also procurement, legal, and any number of departments. In SpaceX's case, it's a walk down the corridor to talk to engineers to discuss the problem and design the fix.

Boeing is also in the dark ages in terms of software development (my field.) SpaceX has a more Silicon Valley/Agile software design methodology where you make many, faster, smaller changes and test them extensively with small unit tests all the way through to hardware-in-the-middle testing to ensure things work as intended. Every tiny change gets rigorously tested to ensure there are no defects or regressions. Boeing's ancient software development process was one of the primary factors in their first Orbital Flight Test failure where they nearly lost the vehicle twice due to software bugs with the mission clock and reentry procedures.

Boeing relies partially on paperwork to validate their spacecraft (whether it's contracts with sub-contractors or studies in place of actual testing) and they've lost the engineers and the engineering culture from the early spaceflight era. //

HiWayne! Smack-Fu Master, in training
1y
50
Ten years they’ve been tinkering with Starliner. That’s crazy. The first crewed Mercury flight and Apollo 15 spanned ten years.
Yeah I know, I know. NASA had an insane budget back then, but damn. Boeing had the benefit of half a century of spaceflight experience and they’re struggling this much to get to LEO. //

Dachshund Wise, Aged Ars Veteran
4y
110

accdc said:
Thank you Stephen, and Eric, for your fantastic coverage of this issue.

Here’s what I (as a layman with little technical expertise) don’t get:

How does SpaceX make it look so easy, and Boeing make it look so, well, ridiculous?

Having worked for or with these companies as an engineer, the most concise explanation I have is culture.

Boeings culture is not technically focused, nor mission focused. Boeings culture is Boeing focused with a particular emphasis on shareholders. The overwhelming majority of managers I’ve worked with at Boeing view engineers as a plug and play commodity and are woefully ignorant of the general subject matter they manage. Many I know at Boeing have an exceptionally difficult time taking responsibility for mistakes that Boeing makes. Whether it’s commercial planes or crew capsules, it’s somebody else’s fault and Boeing knew best. Hubris is rampant across Boeing. What’s fascinating there is that there isn’t a damn thing worth being proud of in recent years, but the cognitive dissonance remains strong.

SpaceX culture is mission focused. Their managers tend to understand what it is they are managing. Their workforce is rather young, however, they test things and are willing to publicly fail in a way that Boeing and others will not stomach. When SpaceX does fail, they tend to take full responsibility, learn from the issue and solve the problem.

SpaceX is more or less doing what NACA and subsequently NASA did in their infancy. It’s nothing new, but it’s a major difference as compared to what NASA and its ecosystem have evolved to since those early years. //

Malmesbury Wise, Aged Ars Veteran
3m
341

TLStetler said:
A big part of the problem is Boeing put too many thrusters in too small a space and operated them at a duty cycle which caused everything to overheat. Said overheating caused vapor lock in the propellant lines, and Teflon seals to soften and swell.

On the other hand, if you've seen images of Dragon with the aeroshell off the thrusters are distributed spatially, not crowded together. Plumbing and control lines are not near the throats of said thrusters.

This is not even rocket science, any decent Hot Rodder knows not to place propellant/fuel lines etc. in a "hot box."

The problems are inherent in the development methods and company structures.

SpaceX insources - mostly because of cost, but also control. There are, deliberately, few barriers between the engineers working on various parts of the system.

The Boeing/Aerojet relationship is a key counter example - because of a arguments over money they started treating each other as the enemy.

Boeing is attempting to design to perfection, then test. If anything goes wrong at the test stage, they are actually in interactive hardware development. Without the hardware, or low cost basis to do the large number of physical tests required. SpaceX assumed they are in iterative development from the start.

During the initial hours of the spaceflight, the crew will seek to fly in a highly elliptical orbit, reaching an altitude as high as 1,400 km (870 miles) above the planet's surface. This will be the highest Earth-orbit mission ever flown by humans and the farthest any person has flown from Earth since the Apollo Moon landings more than half a century ago. This will expose the crew to a not insignificant amount of radiation, and they will collect biological data to assess harms. //

Isaacman's interest in performing the first private spacewalk accelerated, by years, SpaceX's development of these spacesuits. This really is just the first generation of the suit, and SpaceX is likely to continue iterating toward a spacesuit that has its own portable life support system (PLSS). This is the "backpack" on a traditional spacesuit that allows NASA astronauts to perform spacewalks untethered to the International Space Station.

The general idea is that, as the Starship vehicle makes the surface of the Moon and eventually Mars more accessible to more people, future generations of these lower-cost spacesuits will enable exploration and settlement. That journey, in some sense, begins with this mission's brief spacewalks, with Isaacman and Gillis tethered to the Dragon vehicle for life support. //

This is the first of three "Polaris" missions that Isaacman is scheduled to fly with SpaceX. The plan for the second Polaris mission, also to fly on a Dragon spacecraft, has yet to be determined. But it may well employ a second-generation spacesuit based on learnings from this spaceflight. The third flight, unlikely to occur before at least 2030, will be an orbital launch aboard the company's Starship vehicle—making Isaacman and his crew the first to fly on that rocket.

ridley
So to be able to use their spacesuits they need to fit a square peg into a round hole?

Best give Mr Lovell a call. //

Avoiding standard docking and space suit adapters seems like a good way of wasting money and time
The thing that most surprises me about this whole mess is why NASA would ever consider that having a different design of docking adapter and space suit for each type of American vehicle that is to dock with the ISS was a good idea..

That the Soviet G2S vehicles would use different docking adapters and space suit connectors is expected: the two parts of the original ISS design were always intended to use differing docking ports and space suit connectors from the get-go.

However, it beggars belief that NASA would not have specfied a common set of docking adapters for all American spacecraft as well as common space suit interface(s), if only to save costs and re-implementation effort by basing these interfaces on than the well-tested Shuttle docking and space suit connectors. AFAIK those never caused problems throughout their useful life. //

Re: Avoiding standard space suit adapters seems like a good way of wasting money and time

No, giving money to SpaceX was seen as a good way of wasting money and time.

REMEMBER: when this all started, Boeing was the shoo-in, and that goofy SpaceX startup was the complete waste of time and money.

Nobody expected SpaceX to actually ever reach Station.

It never entered anyone's mind that SpaceX would eventually have to rescue a Boeing crew.

The American docking adapters ARE standard.

https://www.internationaldockingstandard.com/

https://www.nasa.gov/missions/station/meet-the-international-docking-adapter/

American spacecraft, INCLUDING Shuttle, either dock to this, or are berthed by the robot arm to a standard pressure door, which allows larger cargo. //

Re: other good ways of wasting money and time
To ensure SLS block 1 would launch by 2016 congress decided to use an upper stage (Interim Cryogenic Propulsion Stage) based on Centaur which has been flying since the 60s. The wimpy ICPS massively restricts SLS capabilities so a new Exploration Upper Stage was ordered for SLS block 1B. SLS is assembled on a mobile launch platform in the vertical assembly building and the rocket and platform are carried out together to the launch site by the crawler/transporter. The MLP includes a tower to fill the core stage and upper stage with propellants. The solid rocket boosters have grown an extra segment each since the space shuttle so the combined mass of SLS and MLP are now sufficient damage the crawler transporter's tracks and they path the travel to the launch site. EUS is longer than ICPS so the propellant connections are at a different height. A whole new MLP is required otherwise SLS block 1B would be delayed because modifications to MLP1 would not be able to start until after Artemis III.

Clearly this situation is untenable. What if MLP2 was completed before EUS? Boeing would look bad for delaying Artemis IV. The solution was simple: do not decide what height the propellant connections will be at until the last possible minute. Bechtel cannot start design of MLP2 without that. Moving the connections also moves the fans that blow hydrogen leaks away before the concentration gets big enough for an explosion. Designing the MLP for a choice of connection heights is also tricky. The platform must be optimized for mass so it does not go much further over the limits of the crawler transporter.

If Boeing and SpaceX had to agree on a flight suit connector US astronauts would now have a choice of rides to the ISS: Soyuz or Shenzou.

Believe it or not there is a worse solution. NASA could decide the shape of the flight suit connectors. Congress would then have an opportunity to help like they did with SLS. Giving Boeing and SpaceX the freedom to work independently of congress (and each other) saves a huge amount of time and money. It also means a flight suit design issue does not ground both crew transport systems at the same time.

After nearly every flight, the upper stage of this rocket breaks apart in orbit. //

A new debris field of nearly 1,000 objects would be a significant addition to the approximately 46,000 objects Space Command tracks in Earth orbit. According to statistics compiled by Jonathan McDowell, an astrophysicist who monitors global launch and spaceflight activity, this would rank in the top five of all debris-generation events since the dawn of the Space Age.

The Thousand Sails constellation aims to provide global internet access. It is one of two planned Chinese systems to challenge U.S. projects including Starlink. Thousand Sails is also intended to secure finite orbital slots and frequencies, and provide national internet coverage and data security. //

The Long March 6A rocket used for Tuesday’s launch combines liquid propellant core stages with solid rocket boosters. The launcher can carry 4,500 kg to a 700-km sun-synchronous orbit. The rocket’s upper stage appears to have suffered debris issues in orbit. //

Like Starlink, China's Qianfan satellites have an easy-to-pack flat-panel design.

A sharp decline in sunspot activity in the 17th century has long puzzled astronomers. //

We realized that this [Kepler's] sunspot drawing should be able to tell us the location of the sunspot and indicate the solar cycle phase in 1607 as long as we managed to narrow down the observation point and time and reconstruct the tilt of the heliographic coordinates—meaning the positions of features on the Sun's surface—at that point in time.” //

German astronomer Gustav Spörer noted the steep decline in 1887 and 1889 papers, and his British colleagues, Edward and Annie Maunder, expanded on that work to study how the latitudes of sunspots changed over time. That period became known as the "Maunder Minimum." Spörer also came up with "Spörer's law," which holds that spots at the start of a cycle appear at higher latitudes in the Sun's northern hemisphere, moving to successively lower latitudes in the southern hemisphere as the cycle runs its course until a new cycle of sunspots begins in the higher latitudes.

But precisely how the solar cycle transitioned to the Maunder Minimum has been far from clear. //

"It is fascinating to see historical figures’ legacy records convey crucial scientific implications to modern scientists even centuries later," said co-author Sabrina Bechet of the Royal Observatory of Belgium. "I doubt if they could have imagined their records would benefit the scientific community much later, well after their deaths. We still have a lot to learn from these historical figures, apart from the history of science itself. In the case of Kepler, we are standing on the shoulders of a scientific giant."

DDopson Ars Tribunus Militum
22y
2,038
Subscriptor

ROOT1803 said:
Serious question: With this much material floating around in orbit, would re-purposing it be something that is feasible? Or is it just irredeemably junk for the most part?
It's infeasible to recover and utilize.

This came up in a previous thread, where I said:
...
On orbit recycling aspirationally saves some launch mass, the cheaper half of the equation, but it forces you to engineer a vast array of complicated system elements for the recovery process and then use in-space manufacturing and assembly processes that will certainly never be cheaper than their terrestrial equivalents where we can walk over to the machine in our shirt-sleeves and clear out a broken milling bit, call the parts warehouse down the road, and have a replacement bit installed same afternoon. The economic network effects are very very difficult to overcome, far harder than any one of the individual engineering problems. //

HuntingManatees Wise, Aged Ars Veteran
11m
100

andygates said:
The problem is that the stuff isn't particularly special, it's just big empty beer cans. The cost is in getting it up there. And it'd be more straightforward (and less expensive) to bring it down than to tugboat the stuff to a space junkyard.

Actual orbital mechanics are left as an exercise for the Kerbals.

I actually spent an unhealthy amount of time in KSP trying to retrieve space junk using a series of giant folding claw mechanisms that would -- in theory -- latch onto dead satellites and then burn for reentry.

This resulted in two or three successful de-orbiting missions, but I gave up after I caught myself tasking my Kerbals with sending up fresh claw ships to retrieve previously-launched claw ships that had run out of fuel.

Astronauts on the ISS tend to favor spicy foods and top other foods with things like tabasco or shrimp cocktail sauce with horseradish. “Based on anecdotal reports, they have expressed that food in space tastes less flavorful. This is the way to compensate for this,” said Grace Loke, a food scientist at the RMIT University in Melbourne, Australia.

Loke’s team did a study to take a closer look at those anecdotal reports and test if our perception of flavor really changes in an ISS-like environment. It likely does, but only some flavors are affected.

Boeing won't start flying operational crew missions with Starliner until a year from now. //

The astronauts who rode Boeing's Starliner spacecraft to the International Space Station last month still don't know when they will return to Earth.

Astronauts Butch Wilmore and Suni Williams have been in space for 51 days, six weeks longer than originally planned, as engineers on the groundwork through problems with Starliner's propulsion system.

The problems are twofold. The spacecraft's reaction control thrusters overheated, and some of them shut off as Starliner approached the space station June 6. A separate, although perhaps related, problem involves helium leaks in the craft's propulsion system. //

MHStrawn Ars Scholae Palatinae
11y
1,142
Subscriptor
Emon said:
The competent engineers and managers were driven out long ago, or they bailed because they were sick of the nonsense.

They're probably working at a variety of competitors or other companies in and around aerospace.

Brain drain is real and Boeing's useless manchild execs either don't understand, don't care, or more likely, both.
So much this.

Boeing going from a company run by engineers whose purpose was to build safe, reliable aircraft to a company run by MBAs whose purpose is to maximize shareholder value was one of the worst developments of the last 50 years in the aerospace industry.

Our beloved NTP protocol appears to work in a deep space environment (as tested in a simulation with a 4 hour RTT):

https://deepspaceip.github.io/testbed/ntp.pdf

Over 5,000 orbital rocket launches from nearly 30 different sites are depicted, starting in 1957 when Sputnik became the first artificial object in orbit.

“Safety tends to not be on the front burner until it really needs to be on the front burner.” //

Since the beginning of the year, landowners have discovered several pieces of space junk traced to missions supporting the International Space Station. On all of these occasions, engineers expected none of the disposable hardware would survive the scorching heat of reentry and make it to Earth's surface.

These incidents highlight an urgency for more research into what happens when a spacecraft makes an uncontrolled reentry into the atmosphere, according to engineers from the Aerospace Corporation, a federally funded research center based in El Segundo, California. More stuff is getting launched into space than ever before, and the trend will continue as companies deploy more satellite constellations and field heavier rockets.

"Look, there's no accidental monopoly. They are a ruthless competitor." //

Most of our customers, you know, we still have new customers, but there's a tremendous amount of returning customers. And if you look at it from their point of view, even if someone turns up with a rocket that is half the price, really the reliability of Electron and the precision of it, it's hard for someone to move onto a new platform. Now, I don't I don't mean that to sound arrogant at all. It's just that price is not the number one thing. It's important, but it's just not the number one thing anymore. I mean, we're inserting to an accuracy of 400 meters at this point. So that's almost good enough to rendezvous straight off the rocket. //

We sold over 22 launches this year, and next year is looking even better. There is a definite demand that small launch has, and a capability that small launch gives. We have just so many customers now that absolutely rely on Electron. They've designed their constellation or their spacecraft around Electron. It does things that you just can't get on other missions. I think a lot of people compare Transporter (SpaceX's rideshare missions on the Falcon 9 rocket) to Electron and dedicated launch, and there is no comparison. Transporter can do it for free for all we care, because the customer who is coming to Electron really needs instantaneous launch, the right inclination or orbital plane. If we just stopped doing Electron, there would be a whole lot of people with nowhere to go. There's been a market built up around the product, and it continues to grow. //

TheWarOnSilence Seniorius Lurkius
9y
10
Subscriptor
I did enjoy this quote:

"We have a saying here at Rocket Lab that we have no money, so we have to think." It is, of course, the re-stating of another famous New Zealand knight of the realm, Sir Ernest Rutherford, who memorably said "We haven't got the money, so we'll have to think".

More than a hundred years after Rutherford made the statement in the context of nuclear physics, it's a delight to see that same drive and determination shine through at Rocket Lab.

It is about 3,000 light-years from Earth, but it can be witnessed with the naked eye. //

NASA predicts a nova will occur sometime this summer, about 3,000 light-years from Earth, but it can be witnessed with the naked eye.

The nova reoccurs once every 80 years. //

The nova should happen in a dark spot among the seven stars of Corona Borealis, known as the Northern Crown.

The dark spot contains “two stars that are bound to and in orbit around each other,” known as T Coronae Borealis or T CrB. NASA nicknamed it the Blaze Star:

On Tuesday, Stoke Space announced the firing of its first stage rocket engine for the first time earlier this month, briefly igniting it for about two seconds. The company declared the June 5 test a success because the engine performed nominally and will be fired up again soon.

"Data point one is that the engine is still there," said Andy Lapsa, chief executive of the Washington-based launch company, in an interview with Ars.

The test took place at the company's facilities in Moses Lake, Washington. Seven of these methane-fueled engines, each intended to have a thrust of 100,000 pounds of force, will power the company's Nova rocket. This launch vehicle will have a lift capacity of about 5 metric tons to orbit. //

Lapsa and Stoke, which now has 125 employees, have also gone for an ambitious design in the first-stage engine tested earlier this month. The engine, with a placeholder name of S1E, is based on full-flow, stage-combustion technology in which the liquid propellants are burned in the engine's pre-burners. Because of this, they arrive in the engine's combustion chamber in fully gaseous form, leading to a more efficient mixing.

Such an engine—this technology has only previously been demonstrated in flight by SpaceX's Raptor engine, on the Starship rocket—is more efficient and should theoretically extend turbine life. But it is also technically demanding to develop, and among the most complex engine designs for a rocket company to begin with. This is not rocket science. It's exceptionally hard rocket science. //

Dtiffster Ars Praefectus
8y
3,002
Subscriptor

deadman12-4 said:
How is a big bulky weight penalty on your second stage good for reuse?

The extra drymass that come from the low density hydrolox is partially mitigated by it's Isp. If the upper stage was expendable, the more than double the volume (and thus likely cost) would be a bad tradeoff for what is close to a push in performance for payload to LEO. But as a reusable upper, hydrogens much better heat of vaporization vs methane and the really low ballistic coefficient are definitely big wins. The low ballistic coefficient combined with lift from their asymmetric design means they can shed velocity very high in the atmosphere where they can reradiate a lot of it back into space. And then when they get lower they use the excellent heat carrying capacity of the hydrogen to protect them from high heat fluxes. From an integrated system perspective, the trades start to make a lot of sense. //

greybeardengineer Ars Tribunus Militum
5y
12,948

Malmesbury said:
Seems like yesterday that Henry Spencer was telling us (and we all agreed) that developing new rocket engines for new launchers was a terrible idea. It would always cost billions. Even warming over old engines was fraught.

And it seemed to be true - see the J2-X comedy.

And no one could match the Russian engines from the Forgotten Years.

Now we have slack handfuls of rocket nerds creating orbital class FFSC engines.

That, right there, is New Space

Once a leadership company achieves something new and very difficult it does two important things: 1) it tells entrepreneurs and investors that it can be done, and 2) a cadre of engineers and managers is created familiar with the technology who are free to move on and disseminate the general understanding of the new technology elsewhere.

As someone once said the greatest secret of the atomic bomb was that it can be built and that it works. Same goes for ORSC. :sneaky: //

That, right there, is New Space

It's quite an accomplishment to blow past the performance of the Soviet/Russian/Ukrainian ORSC engine designs. //

jandrese Ars Legatus Legionis
22y
12,795
Subscriptor++

Bad Monkey! said:
This is amusing considering how long it took BO to get a not terribly ambitious staged combustion engine into production, yet Stoke is all of four years old. Did BO lose all the good ones to Stoke?

Blue Origin is run like an old Aerospace company, which is more risk adverse and slow to develop. Rockets are hard, and being able to prototype designs and work out problems is an enormous productivity boost. Years and years of experience shows that trying to do everything on paper first before building the rocket results in very slow and expensive development. Building engines and blowing up your first half dozen is much faster and cheaper and leads to a better product in the end. //

Wickwick Ars Legatus Legionis
14y
34,700

deadman12-4 said:
How does resources matter. We are talking about a 50 year improvement in technology. This has nothing to do with it being a "commercial" company. Look at China - it'd be embarrassing for them if their engines also didn't blow away old soviet stuff.

I'm not saying "soviet stuff is bad cause its soviet", we need to realize its 50 year old tech. Worshiping it is silly. Everyone should be able to do better than 50 yr old tech, no matter who made it. Its strange how soviet tech is a sacred cow. Its just tech made by someone like anything else. It was good for its time, but that was half a century ago.

You seem to think that "technology" improving just makes everything easier. Sometimes, someone's expertise matters more than technology.

Pratt & Whitney actually had a license to manufacture the RD-180 engine domestically. They literally had the blueprints and everything they needed to know on the metallurgical side to make it happen. They eventually chose not to execute on the license because just duplicating the Russian/Ukrainian design was sufficiently outside of the capabilities of P&W that they felt they would never be cost competitive with the price ULA could buy the engines as imports - duties and all. And lest you think P&W were just a bunch of schleps, they were the makers of the RL-10 engine.

So it's not just a 50 year-old technology. Less than 20 years ago, one of the premier rocket engine manufacturers in the US couldn't make it work even with the recipe. //

I Like Pi Seniorius Lurkius
16y
23

deadman12-4 said:
) How is a big bulky weight penalty on your second stage good for reuse?

Um…you get the stage back… //

Malmesbury Smack-Fu Master, in training
1m
91

deadman12-4 said:
hmm... I would disagree at this point. We're talking about 1970s tech. Yes they were amazing for time, but their time was like 2 generations ago. They are only still relevant because so few engines have been made and used in the last 50 years.
I would say it would be embarrassing if a company couldn't blow past the benchmarks of soviet engines today.

Not long ago, the Received Wisdom from professionals in the industry was that only incremental improvements on existing engines were worthwhile. And possible.

Now, everyone and his dog is building new engines. Using cycles that the pros said they couldn’t do. //

greybeardengineer Ars Tribunus Militum
5y
12,948
Just to be clear, this Stoke first stage engine is methalox. They use hydrolox for their second stage. The article doesn't make that clear and it appears that some in the comments don't realize this. //

phat_tony Ars Centurion
18y
291
Subscriptor

Joey S-IVB said:
445 kilonewtons for each engine, or 3.1 meganewtons for all seven engines combined on the first stage. That's under half of the Falcon 9's approximately 6.9 meganewtons. So, if it can put 5 tonnes into LEO, I'm guessing the second stage isn't as powerful/efficient as the F9's second stage? If this first stage is roughly half as powerful as the F9's booster stage, it is putting less than half the tonnage in comparison (should be about 8.5 tonnes to LEO if half). Still, it's great to see that Stoke is making rapid progress.

Others have pointed out the reusable second stage adds mass vs expendable; but furthermore, you just shouldn't expect rockets to scale linearly at all. Other things being equal, the larger the rocket, the higher percentage of the rocket's total launch mass can be payload.

The SS-520 is the smallest orbital rocket and it's 5,700 lbs and the mass to orbit is effectively 0 - it's 9 lbs. Any smaller and the rocket could not even get itself to orbit.

Some things on the rocket don't scale - the avionics and sensors for a tiny rocket and Starship aren't necessarily very different, so there's a flat mass you need to take. But the most important thing in rocket scaling is that the volume of a fuel tank goes up faster than the surface area when you make it bigger, keeping all proportions identical. The bigger the tank, the lower the ratio of tank mass to fuel mass.

The ground launch sequencer computer called a hold at T-minus 3 minutes, 50 seconds. //

Saturday's aborted countdown was the latest in a string of delays for Boeing's Starliner program. The spacecraft's first crew test flight is running seven years behind the schedule Boeing announced when NASA awarded the company a $4.2 billion contract for the crew capsule in 2014. Put another way, Boeing has arrived at this moment nine years after the company originally said the spacecraft could be operational, when the program was first announced in 2010. //

Crying Croc Wise, Aged Ars Veteran
8m
449

Matthew J. said:
The Boeing Curse...

The McDonnell Douglas Curse.

[Edit to correct]: Actually, it's just McDonnell. Douglas was once a proud airplane maker that sadly became an earlier victim of McD. Boeing is Victim 2.0. //

FabiusCunctator Ars Scholae Palatinae
4y
857
Subscriptor

OccasionallyLeftHanded said:
The term “kludge” comes to mind.

Or more like: “something that was originally designed back in the early days of the Delta program and kept going with bubble gum and baling wire for forty years.”

And I can understand this! The software’s been fully debugged and is well proven. Why change it if you don’t have to? //

Wandering Monk Wise, Aged Ars Veteran
4y
128
Subscriptor
There’s definitely something to be said for the general plan of, “get the system working while shipping cargo, and then add life support”. If these delays happened with a boring payload, it wouldn’t get nearly the attention. //

Lone Shepherd Ars Tribunus Angusticlavius
24y
6,868
Subscriptor

All three computers must be fully functioning in the final phase of the countdown to ensure triple redundancy.

This sentence does not make sense. If all three must be functioning, then there is zero redundancy.

Triplex redundant systems are usually set up to enable majority (2 out of 3) voting to allow mission success while being robust to any single operational fault.

If this was actually a triple redundant system then fault of one computer would be detected by the other two and that unit would have been "voted out" and the launch would have proceeded. ///

But they have to be operational first. If all three aren't operational to begin with, then you don't have a triplex system, you've already lost one to a failure. //

The computers have to provide functionality in the event of a failure after launch commit. That is mission critical, and thats why they need fault tolerance.

Before that, a failure results in a hold/scrub, because it means the necessary failt tolerance wont be present after commit.

Holding/scrubbing isn't an option after commit. At that point the vehicle must go, and the GSE must work. //

ninjaneer Ars Praetorian
10y
540
Subscriptor

galahad05 said:
Wait, this is a joke right? Like a de-motivational poster or something?

He said it in 2004 and it resurfaced everywhere in 2020. The guy's still alive but likely has too much of a psychopathic ego to feel it bite him in the ass.

Ctrl-F "culture" in the Fortune article below and you'll spot it in action

https://fortune.com/longform/boeing-737-max-crisis-shareholder-first-culture/. //

Jharm Wise, Aged Ars Veteran
6y
125

ninjaneer said:
"When people say I changed the culture of Boeing, that was the intent, so that it's run like a business rather than a great engineering firm."
-- Harry Stonecipher

I couldn't believe he would have said so. But sure he did!

Hopefully other business will learn of these mistakes. Many articles (e.g.
https://www.euronews.com/business/2024/02/07/boeings-tragedy-the-fall-of-an-american-icon ) about what went wrong but so far those I have read have all in common that they slashed the R&D for short term gains and then they believed they could easily restart again. This happens when you have bean counters to run the company.

I am sitting in a company of 40.000 people, here we see the same going on. EBIT and cashflow before everything else. No training of new young talent, no visions, just reaction to the competition and not what the customer wants. //

Zylon Ars Scholae Palatinae
3y
838
Subscriptor
I haven't been to this particular facility, but I've crawled around under computer flooring and installed racks at several NASA facilities, and the idea that anything about them is jury-rigged is laughable. You don't truly understand the meaning of the word "nitpicky" until you've been through a NASA QC audit. I spent more time on documentation than I did installing the equipment!

These are stupendously complex systems, and shit happens. I had a timing system that had behaved perfectly during burn-in testing go nuts, and the automatic fail over, didn't. Even though we had tested fail over and fail back. It took the site down for an hour. So you learn from your mistakes, build in redundancy, and when only two of the three voting computers are online at T-4:00, you abort the launch.

Oh, and I wouldn't read too much into the phrase "boot up" when used by a manager, even one who used to be an engineer. Something wasn't ready when it was supposed to be. They'll figure it out. If it was a "network glitch", it will be in the Wireshark archiver. //

Is Boeing having an unusually high number of scrubbed launches? A normal amount? A low amount?

Compared to the Shuttle? Not so unusual. Compared to what we’ve become used to with SpaceX? A lot.

This graph shows the number of sunspots seen each year for 400 years (from 1600 to 2000). There were almost no sunspots during the Maunder Minimum. During the Dalton Minimum, there were fewer sunspots than normal. //

The first written record of sunspots was made by Chinese astronomers around 800 B.C. Court astrologers in ancient China and Korea, who believed sunspots foretold important events, kept records off and on of sunspots for hundred of years. An English monk named John of Worcester made the first drawing of sunspots in December 1128. //

It would appear that sunspots not only have a connection to geomagnetic activity at Earth, but they play a role in climate change as well. In the last thousands of years, there have been many periods where there were not many sunspots found on the Sun. The most famous is a period from about 1645 to 1715, called the Maunder Minimum. This period corresponds to the middle of a series of exceptionally cold winters throughout Europe known as the Little Ice Age. Scientists still debate whether decreased solar activity helped cause the Little Ice Age, or if the cold snap happen to occur around the same time as the Maunder Minimum. In contrast, a period called the Medieval Maximum, which lasted from 1100 to 1250, apparently had higher levels of sunspots and associated solar activity. This time coincides (at least partially) with a period of warmer climates on Earth called the Medieval Warm Period. Sunspot counts have been higher than usual since around 1900, which has led some scientists to call the time we are in now the Modern Maximum.

Kerbal Space Program is a computer game in which the player can build spacecraft, aircraft, and spaceplanes to their own design and use them on missions, both robotic and with crews, to explore the planetary system of the star Kerbol. The space program is conducted on behalf of the Kerbals, inhabitants of planet Kerbin, and the player manages the space program, advancing in technological capability, ambitiousness of missions, and size and skill of the kerbonaut corps. //

One thing which is certain is that after you've spent some time with Kerbal Space Program you will develop an intuition about orbital mechanics which few people, even authors of “hard” science fiction, have.