Welcome to Eager Space I've been interested in spaceflight since I was very young, back in the days of project Gemini. My goal is to explain the spaceflight and rocket details that are often overlooked, be they technical details or explanations for why companies or organizations behave they way they behave.
The number of jobs figure is hilarious. What they are claiming is that they need 3 times the people to achieve the same thing. Great mark of quality and efficiency there ULA.
Falcon heavy is absolutely not 90M per launch, last I checked they previously charged 300M for one expended falcon heavy launch. That means cost is around 3x vulkan while payload is around 2x. For high energy launches it seems obvious that vulkan is a better option unless you are desperate for that mass.
12:23 Ah yes, the Augustine Commision. I remember that I decided to read it in 2013 (I was between high school and college at the time). I agree that it was an excellent report (though I wasn't used to reading things of the sort yet at the time).
11:43 i dont know how you get that 10% for fuel + spaceship it self(hull) but if that is corect they waste payload because the shield for contious impulse it cost 9000kg to avoid burn from rapotrs on hot-stage separation.
Nuclear propulsion has all the disadvantages of Hydrolox. Then a whole bunch more. Edit: SABRE/Skylon suffers from being British. The US has the resources to develop the tech. Edit 2: China needs to stop copying and solve the issues at hand directly. Right now the only country motivated, organized and having the resources is China. SpaceX could beat them if congress/NASA backed them directly. Can't see that happening because of 'pork'. Edit 3: The first LEO fuel depot will be a stripped Starship with secondary kinetic/thermal shield added once in orbit. It's the cheapest solution. Edit 4: Solar beats nuclear for power on earth too. Edit 5: Lunar power will be solar/battery somewhere near the south pole, where the solar arrays can be in sunlight almost indefinitely. Edit 6: Strange to be allergic to alcohol. Is that internally, externally or both. I mean, along with water, ethanol is a great solvent and ethanol is a dynamic equilibrium with water at its highest concentration in any case.
1: if the US could develop sabre why haven't they? Send like a great engine for hypersonic missiles. 6: I get a bad headache and can't sleep if I have more than a few ounces of alcohol. My mother has it, too.
@@EagerSpace dood , you got a weird gene I'm happy not to have. I'm not saying SABRE is simple but the Brits have solved a load of real problems already. Not having to carry half your propellant sounds like a good move.
The fundamental mission of all (orbital) rockets is to achieve at least 9400m/s delta V.... Edit: ULA graphics rely on the senate being rocketry morons. Edit 2: correcting dV.
Seriously, the predictions made in this video demand an update! The shenanigans with the CLPS rover mentioned in this vid alone could have its own entire section....
Nonsense. NASA's path was set in motion in 1995 when the road to commercial launching was developed based on the work of a NASA division chief at Goddard using a white paper I wrote in 1993 from the outside.
16:27 This turned out to be dead on correct since Ship 29 was the first ship to do a flip and landing burn since sn15. And it did it after reentering from Space and sustaining alot of flap damage.
Thanks for the video. The idea of an aerospike always being optimal never made any sense to me. The way a rocket works is by tossing momentum out the back, but since it's a fluid being ejected, you can also imagine it as generating a higher-than-ambient pressure pushing up over part of the cross section of the rocket to produce a force. If there was no [expansion] nozzle then high-pressure gas would just come out of a tiny hole, and so no matter what pressure that exhaust is at, the overall force is going to be very low, and efficiency will be terrible since this highly pressurized exhaust stream will shoot out sideways as soon as it's able, wasting energy that could have been used to push up instead of out. So the nozzle expands outwards, keeping the pressure from dropping by closing off escape vectors, and providing a larger surface area to act over - the walls trap the high pressure gas inside and force it to go up and down. If the nozzle is too small, some gas will still shoot sideways upon exiting, wasting energy (the halo seen when rockets fire in space). But if the nozzle is too large, and the exhaust over-expands to being less than ambient pressure, you get big problems. 1) You're hauling extra weight for more bell than you need, 2) You're arguably pulling a vacuum towards the outer rim which is going to actually pull down on you., and 3) you're going to get bad drag and vortexes as the ambient air tries to infiltrate the bell. An Aerospike gets around this by firing all the gas inwards, producing a high-pressure zone at the center. That zone expands outwards in a gradient, dropping in pressure, until it's in equilibrium with the ambient air. The higher the ambient pressure, the higher the pressure at the center pushing on the center of the rocket bottom. As ambient air pressure drops, the exhaust expands, having lower pressure at the center, but it gets to work over a larger area, which is a net gain. No heavy bell, no flow separation, and no risk of pulling a vacuum from over-expansion. It's a cool dynamic system. But what happens when the ambient pressure gets too low? At some point, in order to expand enough to balance with ambient pressure, the exhaust stream will have to expand to be the full area of the bottom of the rocket. Expanding more beyond that still decreases the inner pressure at the center, but it doesn't get more rocket-bottom to push on in exchange. Now it's just pushing up on the ambient air around the rocket. Whereas a bell nozzle that expanded to be wider than the rocket would provide the surface to still do work on the vehicle. And when you go out into space, with no ambient air, the aerospike should basically perform the same as though it were nozzle-less. You have the fundamental problem that, with no atmosphere, there's no quasi-outer nozzle to keep the gas contained and focus its efforts rocket-ward instead of outward. Maybe the inertia of being throw inwards combined with the spike helps helps (the sloped spike in the middle catches the cross-firing exhaust and gets pushed up, like squeezing up on a push pop) but that means truncating the spike should be a further loss to vacuum isp, and make it perform closer to being nozzle-less and being equivalent to the combustion chamber pressure + the size of the small exhaust aperatures. I'm sure there are other higher-order considerations involved and this treatment is probably making rocket engineers cringe, but it seems that going by first principles, an aerospike can be dynamically optimal inside the atmosphere, but only so long as the ambient pressure is enough to keep the exhaust from expanding to be wider than the rocket bottom. After that point, it will start to lose efficiency compared to an appropriately-sized nozzle, and once in vacuum, its performance should be worse than having any-kind of nozzle, barring any interactions with the spike. Which is what the chart from the blogpost seemed to show. So, nice to have that intuition validated. Every time someone has spoken about aerospikes to me I always feel like they're gaslighting me about basic physics.
In vacuum the aerospike reverts to what ever nozzle they have on the combustion chambers, which isn't great. Aerospike seems like a good idea only if you do ssto, but that's a bad idea to start with. Shuttle would be a good use case but NASA decided just to build a sea level engine with the biggest nozzle they could get away with.
When we build mood infrastructure. Like a permanent base, Permanent station in orbit. When we have capability of making fuel on the moon. We should have a vacuum optimized Spacecraft that never returns to earth. Shuttling passengers from low earth orbit to the moon.
The BIG problem IMHO is that letting private "commercial" companies exploit space, certainly low Earth orbit, will be as bad or perhaps worse than DARPA opening up access to their Intranet creating the Internet. Now everything in human life has its positives and negatives. But, again IMHO opening up the Intranet and creating the unsafe Internet as the Intranet protocols were NOT designed to be secure, created a disaster. Yes, the Internet has many positive uses but it has many more negative uses that have created all this misinformation and disinformation and hacks and hijacking web sites and servers from agents all around the world. Opening space, particularly low Earth orbit, has already created a monster that will come back and "bite" us. SpaceX has launched over 6,000 StarLink satellites to make world wide Internet connection to areas on Earth that are not "wired" for it. That's a positive thing. But, with all those satellites comes the dangers of in orbit collisions and uncontrolled entries in to the atmosphere. I read that just in the first 6 months of 2024, these StarLink satellites and other satellites have made 50,000 firings of small rocket thrusters to avoid orbital collisions to prevent destruction of all these satellites orbiting in low Earth orbit. The US has GPS satellites and Europe wants to launch their own, as well as Russia and China. Already at least two "trunks" from SpaceX Dragon capsule spacecraft did not completely burn up while entering Earth's atmosphere and landed thankfully without any property damage or injury or death to people on the ground. A large battery module was released from the International Space Station (ISS) and a good part of it survived entry in to the atmosphere, crashed through the roof and second floor of a home in Naples, Florida and fortunately no one was injured or killed. But if commercial companies continue to launch many many satellites in to low Earth orbit we may see property and people killed by debris from all the satellites that will be launched in to low Earth orbit. As stated, 50,000 thruster firings took place from January to June of 2024 alone to avoid orbital collisions. These satellites only have a limited amount of fuel and will eventually run out of that fuel and thus could have an uncontrolled entry in to the atmosphere. Ultimately the odds of space debris surviving entry may cause a lot of these (more and more satellites being launched by SpaceX, Blue Origin, etc.) to rain down all over the world. As mentioned in the video, retiring the Space Shuttle or not building a safer replacement, no spacecraft today can bring back to Earth any large space components such as that large battery pack released from the ISS. And NASA's plans to de-orbit the ISS in 2030 may result in large pieces of it surviving entry in to the atmosphere and like all items that burn up entering the atmosphere it will add additional contaminants in to the upper atmosphere. Of course it would require a much larger vehicle but why not push the 925,000 pound ISS out of Earth orbit in to an orbit that would never collide with Earth?
The thing is that they actually had a sucessful first stage engine test recently wich probably is the most difficult and most expensive part to design and build for any rocket so theyy might actually be able to do it. If they get to a reosonable level ov reliabilty within the next two years they could get the onstelation launch contracts that newtron is going for and actually make a profit. I don't think everything is lost but yes, they have a long and difficult path up ahead.
I think it's good that they are making progress on the first stage but the kind of engine they are doing is well validated. The second stage approach is chock full of risk and that's going to make or break the project.
They will eventually get it working well as currently configured, but as currently configured is unsuitable for missions outside of earth orbit. The additional work to the ship to make it suitable to take it beyond earth to the moon or mars will increase the mass which will make it lack the delta V needed to leave earth orbit. I dont believe Starship will ever go to mars, at least not without a radical redesign so extensive that it fails to resemble the current ship at all. I believe it might go to the moon once or twice eventually, but will not be highly successful in moon exploration and science. And I believe it will NEVER be an economic success the way falcon is. SpaceX is learning what a cost-complexity spiral is. And they arent likely to come out on top of it. They are likely to end up with a watered down barely works system that cant meet any of its original promises, and for LEO most missions will still prefer falcon.
Great, great content. I'm binging all your content at the moment, literally the best space nerd detail ever. Fills in all the gaps from the other space youtubers! Many, many thanks
Another excellent historical review and analysis! I fully agree, assuming either SpaceX or Blue Origin lunar landers (or both) are successful, that these programs will take over the task of getting astronauts from Earth to lunar orbit. We'll likely see Artemis 2, 3 and maybe 4 fly, but after that SLS will get decommissioned. My bet is that the transition will happen after Artemis 3, and that there is good chance that SLS Block 1B will never fly.
I'm starting to work on a future of NASA video that will talk about this. It's so hard to predict what Congress will do, but I will say that they are not driven by price and efficiency in most cases.
@@EagerSpace Thanks -- looking forward to it! As has been said (I think it was by space journalist Loren Grush), the Artemis/SLS architecture doesn't make sense as logical architecture but it does makes sense as a political architecture... I suspect the determining factor will be at what point does the tension between two reach a breaking point.
11:31 Imagine putting all that engineering time, effort, and money into designing fake stages when it could have just went to the real hardware itself.
From my understanding of these types of aero-spikes, they still rely on a larger expansion ratio like a normal nozzle for high efficiency in vacuum. It's just a little different with the actual width of the aero spike being the nozzle diameter and the throats of all the combustion chamber throats combined being the throat diameter (I guess thats obvious). I'm pretty sure they can match vacuum nozzles but they have to be very large with small throat diameters but the benefit is that they will still operate at sea level. Of course this probably doesn't matter since they need that extra gas to make up for the truncated aero spike and that reduces efficiency. If what I've learnt is wrong please correct me as I am no rocket scientist 👍
Robert Zubrin some really good writing on the topic of probabilistic safety assessment. He reckoned that the problem with these risk assessments is that people are unwilling to assign a monetary value to a LOC event, because that's a morbid thought. But the problem is that you cannot make program decisions based on probability numbers alone. 1 in 75 looks really bad to anyone, so we say we want to improve that to 1 in 270. Ok, but how much is that going to cost? Do you want roughly 3.5x improvement if if it makes the program 100 times more expensive? Nobody can tell, because nobody knows what the price of an LOC event is. The most criminal thing is that we already put a pricetag on a human life, just not for space missions. One baseline is how much a government is willing on government programs to preserve lives. The median cost for lifesaving expenditures and regulations by the U.S. government in the health care, residential, transportation, and occupational areas was found to be in the range of 1 to 3 million US dollars. Spend more than that and you are wasting money to save 1 life that could have been spent to save 2 instead. Of course an astronaut is not a median or average person, they have highly specialized training and knowledge. A lot of them are former military and test pilots, and pilot training is notoriously expensive, so Zubrin conservatively put the replacement cost of an astronaut at 50 million dollars. If we accept this figure we can finally use some real numbers. The loss of a 7 person crew on space shuttle would therefore cost 350 million for the crew, plus the orbiter itself, in 2020 dollars that's something like 6 billion. So with the 1 in 67.5 empirical probability, each shuttle mission statistically costs about 94 million in risk of total mission loss (not accounting for payload). With that knowledge, you are able to make program decisions. For example, if you know you have 100 future crewed flights in your program, you know you can spend 4.7 billion on on a program to half the risk and break even, more than that and you are wasting money, less than that is a good investment. But you can't make any of these decisions if you don't know what you are actually risking, and it seems that noone in decision-making circles around human spaceflight is willing to determine what the cost of a mission loss is. Which leads to the ridiculous ideas like when they considered abandoning Hubble and not doing a servicing mission after Columbia, which would have guaranteed the loss of an observatory with a pricetag of billions of dollars, citing the risk of a shuttle flight, even though it's clearly shown that that risk is a small fraction of that several billion dollar. Further, you can make comparisons to other historical volunteer pioneers. You can be absolutely certain that Christopher Columbus did not have a better than 1 in 270 risk of LOC that's for sure. But he set sail anyways. And I think this is why human spaceflight capacity is going backwards. People want routine travel risk numbers on a pioneering endeavor, even when it's economically dumb to try and push the safety more.
Even with refuelling in orbit, Starship seems very oversized to deliver a satellite of say 10 tons to GEO. I'm wondering if it would be a good idea for SpaceX to develop an internal third stage to allow Starship to deliver relatively small payloads to high energy orbits.
What was the actual price for commercial sats on the shuttle? Was it heavily subsidized, or did NASA charge full $/kg? If the latter, it would explain why they couldn't compete...
At @7:26 to 8:26 you left out a LOT of COTS history that's critical for context. You forgot to mention that there was Kistler Spaceplanes that was selected alongside SpaceX for COTS first. Kistler was offering their K-1 fully reusable 2-stage medium-lift rocket. Kistler unfortunately couldn't close their business case as well as secure their funding as part of their milestones they were required to meet, and then subsequently kicked out of COTS in October 2007. About 6 months later Orbital ATK was selected to replace Kistler. So, it really took about 5 years from selection to first flight in April 2013 of Antares and then a few months later the first Cygnus flying on the 2nd Antares flight.
I've talked about that in my other videos and decided not to include it here. I also skipped the part where NASA initially awarded a single source contract ($425 million IIRC) to Kistler and SpaceX sued and it was quickly reversed.
I was on the edge of all of these gyrations through out those years. The main accomplishment was to drive out managers with great skill and replace them with ___ _____ who would do what congress told them to do. I am not sure if there are still any flat earthers in congress but certainly there are a number creationists and the remaining hundreds have no effective ability to deal with technology beyond a candle (they call in a secretary to deal with the light switch and an electrician to change a bulb). Its very hard to figure out where to go next. I considered at the time what avenues might be available with ESA. In spite of not having anywhere near the cash ESA has continued a more or less successful program for years while the US Program has wallowed in poor leadership and staggering greed. Force feeding congress a new medicine requiring projects voted for to be funded simultaneously might help a great deal. Stop the Senators and Representatives from telling their constituents that they support the space program but continuing to feed tax cuts to their political donors. It just wont work
It's evident that the key missing ingredient in America's NASA space program is that both NASA administrators and their Congressional conflated-priority Overlords lack the Vision Thing. The "status-quo" system rewards their lowered expectations with less innovation, and has no intrinsic ability to execute daring ideas that thrive in the fertile rich soil of synergy. Synergy is enhanced by funding your own teaching moments through reasonable (low-risk to life) experimental flights; the Space-X approach.
I remember reading someplace just after Columbia crash, Paul Shawcross at NASA HQ proposed to stop flying Shuttle altogether, splash the ISS. NASA get rid of astronauts so its budget can be cut in half, then have NASA focus on research and development missions (which sounds like going back to its NACA roots). But there was too much prestige and international agreements for ISS. I also heard Sean O'keefe had the skills like James Webb as he knew how the Washington DC system works. However, him going to congress mentioning how NASA can save lots of money with methods advocated by VSE was a non-starter for congress. Plus John Pike said VSE was a program to shut down human spaceflight and replace it with artwork. I think what really killed VSE was Gulf War 2. For many people when Columbia crashed it didn't impact the nation as much as Challenger because we were gearing up for war. VSE never got focus because the big focus was the Iraqi war. Kind of like Apollo would have never succeeded if it started in 1965 when Vietnam war was going full size. O'keefe was replaced with Griffin who advocated simple, safe, soon with Orion. As you mentioned the damn thing is too big (I believe it was sized to carry seven crew). In the space forums there were many complaining the ARES architecture was flawed. And the Altair lunar lander simply disappeared. While I don't understand the fine details, I can see why Obama cancelled (or actually recommended) Constellation as I don't think it could have ever flown. I also remembered the wild card was SpaceX, we see if they didn't come along we would still be flying crew on Soyuz. I read Wayne Hale worked with Augustine II committee but he didn't like the options provided all had to have $3 billion price cap. Perhaps just spend a little more and then have an option much better. This was back when recommending new programs that need a price tag, $1B or $2B would be too low. $5B or $10B would sound like don't really know the cost so estimate a basic number. $3B sounds like there was a real cost estimate study.
Cost-plus sounds like a decent strategy if there's *external* incentives to succeed. Self-preservation during wartime sounds like a pretty decent incentive. But if there is no big incentive, then I fail to see why a contractor wouldn't use it as a piggy bank.
So when commercial companies take over the operation of space stations and send landers to the moon NASA will only run the SLS and Orion? And that the European Service Module is made by ESA so only part of the Orion space craft is made by NASA. They will become irrelevant.
This is probably the best explanation of how NASA went from being able to develop and fly three different spacecraft in a decade to not being able to get a single launch system built with existing parts to space in 20 years. Amazing work!
@@TheEvilmooseofdoom You've got that right! Sorry, it was just lying there... Sigh, I know that's not what you mean. Private contractors actually build the rockets. NASA manages the process, from design through construction. That is what they've lost, the ability to effectively manage engineering projects as opposed to operations, but I don't think anybody misunderstood that from what I said originally.
So when it was greenlit, the SLS was expected to be the only U.S. rocket capable of reaching the moon, and now SpaceX is well on it's way to doing the same for less. I'd look for ways to reinvent myself if I were SLS supppliers.
Crazy to think that without SpaceX, congress would still be biting their tongues while buying launches from Russia despite their wholesale sanctions LOL
@@EagerSpace I mean, just because someone does not dive deep into engineering as they did not happen to major in engineering, does not mean they can't criticize SLS, or starship, or blue moon, when these use taxpayers' money, and covered by reliable sources.
