Ultimate Steve

Hello, a few of you may be aware that I spent two years working on this little guy: This is CySat-1, a 3U CubeSat designed to measure Earth's soil moisture using a software defined radiometer. The long end of that umbilical cable is currently hanging up on my bedroom wall, and everything else is currently orbiting the Earth as a nonfunctional and quite expensive brick (or maybe it has re-entered by now, or maybe a miracle has happened and they made contact but didn't tell me, but I'm going off what I last heard). In addition to being a nonfunctional brick, it is also a little box of pain and suffering and joy and relief and learning. I have a lot of stories to tell about this thing which has repeatedly tested my technical ability, my sanity, my understanding of my own self, and the limits of my emotions, among other things. I might eventually write a book about it, but that's a ways off, and I figured since a few of you have expressed interest, that I would put all of those stories in one place. I'll update this thread with new stories as I remember them or as I find the time and energy to write them all out. I hope to describe here a lot of the herculean (for undergraduates) technical challenges we had to overcome, and possibly some of the emotional challenges I had to overcome, in the pursuit of getting this thing up in the sky. If you've read my mission reports, expect a similar feel, but this will be my first time writing this way about events that actually happened, so it looks like this loaf of bread sized angry box of silicon and copper might still be requiring me to learn new skills haha. While I will not use names, it is reasonably possible to put a name to the alias, I will ask that you don't do that and that you certainly don't contact anyone involved. There are two "Overview" stories to provide the context necessary to understand the rest of the stories. If you have any questions, please let me know, talking about this thing is one of my favorite things to do. Acronyms and Glossary SDR - Software Defined Radio (in general) or Software Defined Radiometer (referring to the specific instrument on the satellite) EPS - Electrical Power System ADCS - Attitude Determination and Control System UHF - Ultra High Frequency, usually referring to the satellite's UHF Transceiver FPGA - Field Programmable Gate Array, sometimes referring to the satellite's SDR instrument LNA - Low Noise Amplifier OBC - On Board Computer UART - Universal Asynchronous Receiver/Transmitter - A serial protocol for exchanging data I2C - Inter-Integrated Circuit - Another serial protocol for exchanging data GNU Radio - A software defined radio program C&DH - Command and Data Handling M2I or M:2:I - Make to Innovate I will note that all of this is from my best recollection of events, some of which happened over two years ago. There's no way I'm gonna get everything 100% right. I will probably put a number of events out of order. Story 1 - Project History and Hardware Overview (So you know what I'm talking about when I reference a particular part of the satellite) Story 2 - An Overview Of My Time On CySat-1 This generally goes through a summary of events as they happened - Individual events can have stories behind them as long as this entire section, this is just an overview to show the general timeline and how events may have fit together. This is significantly longer than I hoped it would be. Story 3 - The "Invalid Telecommand ID" Incident, The Most Enigmatic Bug I've Ever Had To Deal With Stories I haven't told yet but might at some point How we broke several thousand dollars worth of solar cells How I finally contributed in a meaningful way to the hardware Our two failed attempts to meet launch deadlines NOAA and remote sensing CySat-1: A Geopolitical Nuisance to Iran's Reconnaissance Satellites The balloon flight test Deciphering the UHF's Packet Protocol, and my happiest moment ever on the project Interrupt Priority Conflicts How one misspelling meant the ADCS didn't actually work The Surprise Carrier Board Swap The worst solar power testing setup in the entire world The Batteries How I fried the OBC and recovered in under 2 days The Ground Station Software, an exercise in multithreading The emotional side of the journey The test files, "And what is the use of a book," thought Alice "without pictures or conversations?" The LNAs and my hardware incompetence (including reverse engineering the machine used to mint an EE Master's Degree) An exercise in improper calibration The broken cable incident The Roomba cable incident The part where we stole mosfets from a submarine and sent them into space The part where we thought about stealing another professor's radiometer The trouble with the radiometer's power consumption The screen going blank and our efforts to re-image the satellite's SD card The @*&^#!*&^ antenna The !*&@#^*&^ ground antenna That time we plugged the entire satellite in wrong The RTOS and random freezing The ADCS off by one error The ADCS and TLE APIs The story of the sun sensors (which is also to an extent the story of the solar panels) A few small anecdotes of me being in waaayyyy over my head CloneComm and how it was named The early days when we didn't know what we were doing (LED debugging, how to turn it on, the pumpkin board, etc) The grading fiasco and why I accidentally graduated several months late How not to design for assembly That time we almost costed the university a fortune in storage fees by accidentally pushing a multi gigabyte radio recording to Github How we almost launched CySat into space with the RBF pin wired incorrectly The never ending struggle to keep the roller switch wires from falling off How I picked up the pieces of my shattered dreams, glued them back together, and moved forwards stronger (hopefully, this part is still being written) As you can see, there are a lot, and those are just the ones I remember off the top of my head. Gather around the campfire, because we may be here for a while! Let me know if there's any particular story titles that catch your eye or if there are any questions you have.

Given that the future of SLS's involvement in the Artemis program is up in shambles, I'm gonna muse over some various options for what could be done to replace it. From what I've thought of there's three main families of options. Family 1: Distributed Lift. This usually comes in the form of Orion getting launched on one rocket and a rocket stage getting launched on another rocket. Orion was at least at some point designed to take the force of engines firing through the docking port as it would have been required to back in the Constellation days. I'm unsure if this capability has been retained. Orion masses around 27 tons on its own, 34 tons with the launch escape system. This is beyond the capacity of Vulcan Centaur, but can fit on New Glenn and Falcon Heavy. Both would require a new adapter but it would likely be easier on New Glenn as it is wider, and you could taper down to Orion's diameter rather than having to taper up or do a Starliner style overhang - though Orion's diameter is smaller than the Falcon Fairing diameter so it shouldn't be too wide). Using Falcon Heavy gives you the advantages of flight heritage and having a crew access arm already at the launch pad (though it will likely need modifications to sit at the right height and have an appropriate interface). A challenge with this approach is that Orion is designed to be vertically integrated. Both Falcon Heavy and New Glenn are horizontally integrated rockets. Orion can be transported horizontally without propellant and without the LAS attached, but sticking it on a Falcon style transporter erector fully fueled and with abort tower is going to take some effort. I'm not sure how much effort, but not zero effort. The LEO launcher could also be a custom expendable variant of Starship - Starship of course has the performance to lift Orion's mass in reusable mode but it needs to be mounted on top for the LAS to work and Starship can't re-enter without its top. Starship is vertically integrated so it has that going for it, and it has more flight heritage than New Glenn, but SpaceX likely wouldn't want to make a custom expendable variant and changes to their launch towers especially with how much they are iterating right now. There's no clear winner for the launch vehicle IMO. Then the question is, which launcher launches the space tug? Vulcan Centaur can't, even if the structure was massless, 27 tons (VC's max payload) of propellant at an RL-10's isp can only just barely push Orion's mass to TLI. Real rockets aren't massless, real rockets have boiloff, and NASA doesn't like pushing rockets to their maximum (NASA's rocket performance calculator lists a maximum payload for reusable Falcon 9 that is below what they regularly do for Starlink, and Vulcan's numbers are lower on NASA's calculator than ULA's website). Falcon Heavy fully expendable can do it with at least ten tons of margin. However, the timing would be tight without modifying it for long durations. Currently it can only do a few hours. Once you launch you have to commit fully to the other launch at the next launch window (unless you arrange the orbits at just the right way so you get two valid windows in rapid succession, but the odds that it lines up with the orbit you need to get to the moon are rather low). If you launch Falcon Heavy first and there's a problem with Orion, Falcon dies in orbit and the launch campaign is over. If Orion launches first, well, actually that could work. The crew may have to spend a few days hanging out in LEO, and risk having to come home if a showstopper issue delays Falcon more than a week or two. An amusing solution to this is to perform both launches timed simultaneously and with their launch commit criteria wired up to each other. Falcon Upper Stage's acceleration at burnout would be very high compared to say, Centaur, but if Orion can still handle the forces it was expected to for Constellation, it can probably handle Falcon. If not, big problem, as at a minimum, peak force would be above 1 G. New Glenn, I'm much less well versed on. BE3U has an isp of 445s, and at New Glenn's maximum payload (reused even) it should be able to do the job (though early versions of New Glenn are reportedly severely missing payload targets), though boiloff is as always a problem. They do want to create a variant of GS2 for refueling Cislunar Transporter so it may end up being a fairly straightforward modification. Centaur V would be a really good option here as they really want to do zero boil off long duration, and it has a very low thrust, but unless they stick it on a New Glenn, it is not going to happen. Starship is an option but largely redundant, same talking points as for Orion. There's also the consideration that you would want to have this happening on two separate vehicles or deal with turning around your launch pad really quickly for 2 launches with the same vehicle (or building 2 launch pads, or doing zero boiloff forever duration upper stage). Family 2: Single Launch Orion This is a family inhabited solely by expendable Starship and even then only maybe. It is highly dependent on what the dry mass and payload of an expendable Starship would end up being. At one extreme you have a 120 ton vehicle with 100 tons of payload+prop that won't even get to 1500m/s of Delta-V, and at the other extreme you have a 40 ton vehicle with 200 tons of payload+prop which has 4.5km/s (waaaayyyyy more than needed). If you expend Super Heavy I can almost guarantee that the numbers close but SpaceX won't want to do that. Assuming that it does have the required performance it is an attractive option for its simplicity. Vertical integration, no rendezvous, no force through the docking port, and more flight heritage than any other option on the table besides Falcon Heavy. The catches are that for a reasonable timeframe you have to move Orion integration to Texas, you have to create a custom Starship variant, you have to crew rate Starship (and possibly commit to a design freeze) far ahead of schedule, with SpaceX really doesn't want to do, and you have to make modifications to Starship's launch tower. Family 3: No Orion There are 3 options in this family that immediately come to my mind as credible. Option 1: Whatever Blue Origin is cooking up with Cislunar Transporter and their crew vehicle. Can't say much about that as it is still very much a mystery. Option 2: Lunar Dragon. I don't think this is going to pan out as SpaceX doesn't want to invest in a system they hope to make obsolete in the same timeframe. New service module for Dragon, somehow maintaining abort capability, upgrading the heat shield. Dragon is ~12 tons, it needs ~8 tons of propellant to have as much Delta-V as Orion (though that may be a bit high as that doesn't take into account the propellant Dragon already carries), misc upgrades and service module mass, let's say it comes out to 1 more ton. The stack is 21 tons, and Falcon Heavy Expendable's TLI capacity is, well, unknown. Most estimates place it somewhere in the 21-23 ton range. On paper it fits, and SpaceX may do something funky with propellant utilization and a draco nozzle extension to reduce Lunar Dragon's mass, or not take as much Delta-V as Orion, so it wouldn't surprise me if it could work. But again, NASA does not like pushing its launch vehicles to their limits, so I have a hard time seeing this being selected. Option 3: Lunar Starship, but not in the way you think Depending on your chosen performance characteristics, Starship is maybe capable of going from LEO to the Lunar surface and back. Probably not. This requires a lot of optimism and no payload. However, I recently saw another option making its rounds online. The idea of using two Starships. HLS Starship is expended as normal. A crew Starship is refueled in LEO and goes to the Moon, transfers its crew to HLS, HLS lands and ascends, and crew Starship takes them back, and - crucially - propulsively brakes into LEO. It has the performance to do this, this saves the necessity to develop a Lunar rated heat shield if that becomes a significant barrier. Of course then you have to commit to putting crew on Starship through ascent and landing sooner than you otherwise would have, which is probably not the best idea. Expanding upon this idea, depending on the masses involved, you might also be able to use crew ship to refuel HLS ship and reuse HLS ship, though it would probably require a Lunar rated heat shield if the refilling was to be done all at once, and delivery of heavy cargo to the Lunar surface would require some way to transfer that cargo from crew ship to HLS ship. And then there's doubtless more options of various practicality that I haven't listed here or haven't thought of. The next few years will certainly be interesting. We may see a request for proposals for commercial Lunar crew transportation within the next few months. Reading the source selection statement for that is going to be interesting.

Ohhhhh silly me. The bladder is to prevent the ice from making it to the propellant. My bad.

In both of your scenarios there you still need gas, it is just that there is something between the gas and the propellant. I think bladders are more for zero g fluid management and are useful if you don't have/can't have ullage/settling thrusters. Going back to the case of Super Heavy, the gas isn't there to help with fluid management, it is there primarily for two reasons, firstly, to take up space. If all that propellant that the engines used was not replaced with something, the declining propellant level would pull a vacuum to an extent inside the tank, and the atmospheric pressure would crush the booster from the outside. Secondly, to provide structural strength. Think about how strong an opened soda can is vs a sealed, pressurized soda can. The walls of the booster are made enormously more resistant against buckling and crippling failures when the booster is pressurized. For an example of why this is important, refer to the SN3 failure. 6 Bar seems a bit excessive for that but hey what do I know. In a vacuum, you can get away with lower pressures, the limiting factors are going to be the boiling point of your propellant as that changes with pressure, and needed structural strength during maneuvers and re-entry. On the surface it seems like Starship should be able operate at a lower pressure than Super Heavy, but it has to take a lot of sideways loads during re-entry, so I would think it remains highly pressurized for structural reasons. I can't really think of a use for a bladder in this case besides eliminating the need for settling thrusters, which Starship has anyway for reaction control.

Sooooooo, remember that little drama from a few months back about how SpaceX was using preburner exhaust to directly pressurize the tanks? Some people: "This would explain the engine issues with Super Heavy on flights 2 and 3 and possibly the Starship RCS issues on flight 3, and would also explain why the heat exchanger hardware went missing" Some other people: "There's no way they would be that mind numbingly stupid to send several tons of ice into their tanks? How the hell did these idiots think that was a good idea if they actually did do that" Elon: "We are using the preburner exhaust to pressurize the tanks" (from Everyday Astronaut video, not exactly said but highly strongly implied) Some people: "This probably saves on preburner mass" Some other people: "So they really are that stupid and are doubling down with several tons of ice filters" (I have not seen confirmation of this but I have heard they have a giant metal mesh strung across the bottom of the booster to catch ice chunks and sheets) Well, in arguing against a separate argument, I checked the numbers for Super Heavy's ullage gas mass (or tank gas mass, or whatever you want to call it), and I think I figured out the actual reason why SpaceX ditched the heat exchangers and is having to deal with tank ice! Assumptions: V1 capacity, ideal gas law, Super Heavy's tank is entirely liquid oxygen (I can't be bothered to do the math on methane as well), Super Heavy is pressurized to 7 Bar (6 Bar above ambient, not sure if that is the correct number but I've heard it thrown around). Disclaimers: I keep accidentally writing "degrees Kelvin" despite a Kelvin degree not being a thing, it is just called a Kelvin. Deal with it. I'm not exactly sure what is traditionally done for autogenous pressurization and I'm not exactly well versed on heat exchanger design, so I may get a few things wrong. But say you want to pressurize Super Heavy. It has a volume of roughly 4400 cubic meters (we don't know exactly but I rounded to a nice number near what a 70x9m cylinder would be). Traditionally you would want to be able to hold your tank in equilibrium before launch. Liquid Oxygen is roughly 90K (though SpaceX subcools theirs, I'm not gonna get into that right now), and you would want to pressurize with a gas also at 90K. There's not much that is a gas at that temperature. Let's try Helium. At 90K, that 4400 cubic meters is about 4,167,000 moles. At Helium's molar mass of 4g/mol, the ullage gas in Super Heavy would come in at about 16.6 tons. If we have had a little bit too much to drink, we could instead try Hydrogen, which would work, and would get the mass down to 4.2 tons with a molar mass of about 1g/mol. However having a tank with both hydrogen and oxygen inside of it is not advisable. This is great and all, but helium is mega expensive. It costs more than the liquid oxygen does on Falcon 9. That works fine for small to moderate fight rates from Earth with small expendable or partially reusable rockets. But, at Super Heavy scales, planning for a future in which the fuel cost becomes significant, the cost becomes very significant. And helium is a fossil gas. We have a limited amount of it, and the flight rate necessary for even a small Mars colony would vastly outstrip supply - The United States produced about 14,000 tons of helium in 2023. All of the United States' helium put towards Super Heavy launches (without even talking about Starship itself) would be enough for 850 a year. Which is a lot. But the rest of the US, and the rest of the world, needs helium too. It would be possible to have some sort of reclamation system to recycle the helium after each launch. But I digress. That was a long tangent for something that is not in any way related to my main point. Plus you can't easily get helium on Mars. TLDR: You don't want to use helium, and hydrogen is a bad option. So, that brings us into the wonderful world of autogenous pressurization. At its most basic, you take some of the liquid propellant and boil it into a gas, and if you keep it at the same temperature (providing only the latent heat of vaporization), you get a nice mixture in thermodynamic equilibrium. However, you do have to take care and control it - with subcooled propellants, you cannot have a mixture in equilibrium, and the gas will gradually cool and, without care, condense back into a liquid, and your tank pressure drops, and your tank collapses. Hydrogen on the surface seems like a wonderful fuel to do this with. Its absurdly low molar mass means that in theory it should be great at this. However, remember our good old friend PV=nRT? Hydrogen would be in equilibrium at 20K, 4.5x less than the 90K we were talking about earlier, and a hypothetical Hydrogen fueled autogenously pressurized Super Heavy would have 18.7 tons of ullage gas. Still alright. But that 20 Kelvin, that's really killing us. Back to liquid oxygen. Super Heavy with equilibrium oxygen ullage gas, with it's comparatively extreme 32 grams per mole molar mass, at 90 Kelvin, well, you'd need ONE HUNDRED AND THIRTY THREE TONS of it to fill Super Heavy's tanks!!! That's absurd! That's a really large percentage of the entire dry mass of the Super Heavy booster! That is completely untenable from a rocket equation perspective to be pushing around 133 tons of extra mass. Note: Methane is 16g/mol so these numbers are artificially more extreme than the true numbers through only considering the oxygen, but I'm lazy so. You do the math if you want to see more accurate numbers. Looking at PV=nRT, and m=n*molar_mass, we can't really use a different gas, so molar mass is fixed. Thus we must minimize n to minimize n, and in order to do that, we can do 4 things. 1: Alter the laws of the universe to change R (quite unrealistic). 2: Reduce pressure. This means more structural mass to avoid collapsing the booster. Not good. 3: Reduce volume. You can't really do this without carrying less fuel, though subcooling does help to an extent. And then there's option 4... Raise the temperature. (Note: While writing the previous section I completely forgot that liquid nitrogen is colder than liquid oxygen, so nitrogen is a valid ullage gas, though its molar mass is not much better at 28g/mol, but it doesn't flow as well if I include N2 and I've already tangented too much so I'm leaving it out) (SECOND NOTE: On Falcon 9, SpaceX subcools the oxygen to 66.5K, lower than the point where nitrogen liquifies. Starship is likely similar, so I accidentally was right but for the wrong reason, nitrogen is not an option) Welcome to the world of, there's probably a technical term for this that I'm not aware of, "Non-equilibrium autogenous pressurization." Maybe you start out with the tanks in equilibrium so you can have better chances at making it through a launch hold, but at launch, you then start flooding the tanks with warmer gas. The same mass of gas at the same pressure will take up more space, so you need less of it! The catch is that now your fuel tanks are dynamic and heat will transfer between your fuel and your ullage gas throughout the flight. Not very much as it is only happening for a few minutes, but the temperature of your gas will change, and your fuel levels will change as, depending on the temperatures, some propellant may convert to ullage gas or some ullage gas may convert to propellant. TANGENT: This could be a small part of the motivation for continuous acceleration during Super Heavy staging. With an engine cutoff, the liquid and gas would mix and more readily exchange heat, resulting in either a pressure spike due to propellant boiling, or a pressure drop due to ullage gas condensing, depending on how things are set up. This effect would probably by my intuition be minor, but every little bit adds up, and continuous acceleration keeps the surface area between the ullage gas and the propellant fairly constant. The space shuttle did this for its hydrogen. I'm having trouble finding the exact temperature, google isn't turning up much, but one source claims that the hydrogen tank gas averaged around 250K. This is 12.5x hotter, and therefore lighter, than if it was done at equilibrium. If we do the same, and put the Oxygen at 250K, the ullage gas mass goes down to 48 tons! This is amazing progress! Now you're probably thinking "Duh, hotter gas = less mass, that's why they are using the preburner exhaust" and no! That's not quite it. There's more to it than that. Typically you would use a heat exchanger. Let's say you are heat exchanging between the preburner exhaust and some liquid oxygen in the tank. The issue is that it gets a lot harder to heat exchange with something once it turns from a liquid into a gas. Heat transfer through a wall in Watts is proportional to the surface area. However, once you boil a liquid, its volume dramatically increases, and its speed through the piping would increase as well, unless you did some weird trickery with choked flow to keep it "only" at the local speed of sound (which would still be increasing as you heated it up). You would need more surface area to keep in contact with the same mass for the same amount of time as the density is so drastically different, though presumably the density is still rather high at this point. That gets worse the hotter you get the gas as it will take up more and more space, so you either have to increase the pressure or keep making the heat exchanger larger and larger with diminishing returns for each extra Kelvin you want to raise the temperature. Tangent: I know some space missions keep fluids supercritical to avoid stuff like this from being a problem, it might be possible here to avoid much of the heat exchanger scaling issues by keeping the oxygen as a supercritical fluid. You know what else has diminishing returns? Heat transfer rate is also proportional to the difference in temperature between the two sides of the wall. As the temperature of the oxygen gets closer to the preburner exhaust, you need more heat exchanger are per degree for each degree closer you get. AND, the preburner exhaust is also cooling down throughout all this. I have no idea how hot Raptor's preburner exhaust is. But let's say 400K because it is a round number that is close ish to a very old number I had on a spreadsheet. It is probably off but the exact number isn't important. Exactly how cold it gets depends on how the heat exchanger is set up and the ratios between the gases. But the oxygen by definition cannot get up to 400K by cooling something at 400K unless the ratio is infinite. So your 400K preburner exhaust may only get the oxygen up to like 350K (random number, could be 395, could be 300, who knows). And then, that's in ideal conditions. As I stated above, you get diminishing returns for each additional kg of heat exchanger you add, each extra one raises the temperature even less. So you're gonna get a lower temperature than even that. Okay, but how much does that lower temperature affect us? At 300K, you would need 39,989kg of oxygen. At 301K, you would need 39,857kg of oxygen. That is a 132 kilogram difference. The difference between, say, 400K and 350K is 4.3 tons! Again, I'm not quite sure what the preburner exhaust temperature is, it could be 600, it could be 250, who knows. And I don't know how close SpaceX can reasonably get to that preburner temperature with a heat exchanger alone. The difference between ONE Kelvin at high temperatures (which are worse for my point) is over 100 kilograms and the benefit is almost certainly several degrees at a minimum. Taking it to the extremes, the difference between what the shuttle got to (250K) and 400K is nearly 18 tons! And the point that I have been building to: This isn't about the mass of the heat exchangers, it is about the mass of the ullage gas! The mass of the heat exchangers is purely an afterthought! This isn't even about the difference between equilibrium temperature and preburner exhaust temperature, this is about the difference between heat exchanged exhaust temperatures and direct exhaust temperatures, which is significant even if it is only a few degrees! Hundreds or thousands of SpaceX employees labored day and night to save 38 tons in vehicle mass with the gap between Raptor 2 and Raptor 3, or ~3.5 tons counting just the engine side stuff (vehicle side commodities is most of the difference). In a world in which they spent countless hours wizarding even more performance out of Raptor for arguably 3.5 tons of weight shaving, shaving several tons (I'm not claiming to know an exact number but even ten degrees at high temperature is over a ton) of ullage gas mass simply by deleting a part to get higher tank temperatures is a no brainer! Of course that does come with the costs of ice filters, and possibly having to wait for the ice to melt between flights if they do get to the point of multiple flights per day. But unless they actually have several tons of filters on board it is well worth it. A tangential benefit is slightly better cold gas thruster performance as the total temperature and therefore exhaust velocity is higher. I wouldn't be surprised if they intentionally run Raptor's preburner hotter than they would otherwise just to get tank temperatures higher. TLDR: I believe that Starship uses the preburner exhaust directly as tank pressurant because this allows them to get the tank hotter than they would have using a heat exchanger exchanging from the very same gas, without the additional mass of a heat exchanger, but with the additional mass of ice filters. The exact numbers don't matter because the effect is significant at only a few degrees of difference at high temperature, but the effect could plausibly be comically large with a few tens of degrees of difference at moderate temperature.

In addition, the Artemis II heat shield was built in a way that resulted in it being even less permeable. From what I remember they intend to fly it as is with a modified entry trajectory to offset the decreased permeability (and hopefully then some).

It is very clean looking. Quite a stark contrast to the early days when they thought they could get away with significantly more than they ended up getting away with.

Ow, well that's embarassing. I've been spelling Isaacman's name wrong all these years! Sorry, Jared!

Hmm, that's eye opening. The Isaccman connections feel a little more solid but this definitely reduces my concern. I was less talking about the congressional budget and more contract decision making - E.G. Congress funds a lander, NASA has to choose who to give the contract to. However I seem to have misremembered who has the authority to sign off on those decisions. For some reason I was under the impression that it was the administrator, but upon further examination, it does not appear like that is the case. Thank you for correcting my misconceptions. I haven't been following space long enough to make this assertion confidently but in recent years I would say yes to this. With that out of the way I'm now significantly more confident in Isaccman. These should be an interesting four years indeed.

This could either be really good or really bad. My full opinions on the matter would probably break the no politics rule so I will try to steer clear of anything too far, but the Moderators are welcome to edit this if I do go to far. Mr. Isaccman has had two once in a lifetime experiences because of SpaceX with another two on the way. Putting him in a place where he has some amount of power over one of SpaceX's largest revenue streams and American space policy in general, well, at the very least that is a massive conflict of interest and should be setting off alarm bells, though by itself is not immediately a showstopper. And that is before even getting into how Elon's new committee position arguably gives him a knife at the throat of the regulatory agencies that have impeded, justly or not, SpaceX and his other companies. It does not sit right for me for one company to possibly have so much control over the government agencies that fund and regulate it. There are also a lot of green flags. He isn't just a guy who paid to go to space. He has emphasized the scientific, exploratory, developmental, and humanity centric aspects of what he is doing at every step. He very much appears to be a "going to space for the benefit of Earth" person. From his recent tweets he appears solidly in the middle politically, has a really strong passion for space and spaceflight, and has urged the government to not cut funding for the Chandra telescope in the past. He had a really old (2022) tweet saying he did not agree with the decision to fund two landers. I disagree with this for the time being. I don't think it is wise for the government to go all in on Starship just yet, though if they keep improving at the rate they are, my opinion will likely change in the next year or two. Granted his opinions may have changed since then. I would say I am cautiously optimistic. There is a lot of potential for him to do a good job, but there is also some potential for conflicts of interest, up to and including some level of "cancel everything and give it to SpaceX." Which is weird because that is arguably the correct thing to do in many cases and it may be difficult to distinguish motivations. We may very well end up in a situation where a lot of cool stuff gets done, but I may not approve of how it is being done. He at least in passing has acknowledged climate change as a problem in a 2022 tweet (google being dumb and I am having trouble finding anything more if it exists) so we are already one step better than Bridenstine, and he turned out to do a pretty good job.

Oddly enough it came out to 50/50 exactly the last time I ran the numbers, but I had done a large burst of applications in the preceding few days so turning back the clock a little to allow for response time, it is more like 55-60% rejection and 40-45% no-response. If I separate out the interview -> rejections from the rest of the rejections it is still pretty close to 50/50. Thank you for the reassurance, it really helps a lot. I've been working on a simple multiplayer N-body space combat game recently, not pretty at all, mostly a tech demo for internet communication, I think I can make space for it on my resume. I have also scheduled a meeting with my university's career advisors.

Ah, let's go read the SpaceX thread for today, looks like a rousing discussion on the economics of Starlink and - Oh. And that's after moderator editing.

Job hunt update! Back in September I got four interview offers in rapid succession and I slowed down my pace of applications, both to focus on the interviews and also because "There's no way I mess up all four of these right? And there's a fifth one I'm already done with waiting on the answer." Company 0: Interviewed months ago, they finally got back to me with "no" for a position 2 levels higher than the one I interviewed for. Company 1: Upon learning more about the job I decided I didn't really want it and decided to push the envelope a little with interview style. Did not go well but now I know. Company 2: Made it to the second phone interview, not exactly sure what in specific went wrong but it was kind of Meh all around and this is a competitive place to get into so there were doubtless far better suited people. Company 3: Did 3 rounds of phone+online interviews, they said that I would be better in a hardware focused role on an adjacent team and had me restart the process for that position instead. I made it through 2 rounds and then they rejected me (apparently none of the candidates they interviewed were to their tastes so they opened up applications again). Company 4: Things went really well. They flew me out for an interview. The in person interview went well and somehow nothing went wrong with the travel. They say I'll know within a week. Recruiter contacts me and says that there's been a delay and that I'll know in another week. Today I finally hear back and - The team thought I did really well, but the position has been cancelled and the needs of the team have been re-evaluated so they will be looking for a level 3 person instead, and also the company is dramatically refocusing hiring on one of their other projects at the expense of everything else. Six months after graduation, no more active leads, 119 job applications and counting, I'm now competing with the 2025 graduates, here we go again. I'm starting to doubt my competence at this point. At what point does the employment gap get so large that I'm unemployable? At what point do I give up and just be a bus driver my whole life? Could I handle a part time job and graduate school at the same time, as there's no way I'll be able to pay for it otherwise?

In a recent talk Gwynne said that this is projected to be Starlink's first profitable year, so there's that.

Successful landing! The results of the past three flights have been very good omens for the survivability of the ship once they put people on board. Not so good omens for the goal of a rapidly reusable heat shield, but hopefully that's something V2 will address. They put this ship through a very aggressive re-entry, with a decent chunk of the tiles missing, and other tiles testing various other things, and she made it through with less visible damage than the previous two flights. Lots of wonderful camera views!

Good relight it looks like.

Possible reason for catch abort:

Stream live and forum back up! T-9 minutes, showing off some new HLS renders and some windows. Pushing ship beyond limits in many respects to find exactly where the limits are, unlikely it will survive.

Oh, you know me, short bursts of intense writing and months long gaps of nothing.

I don't think that multiple passes would significantly reduce fuel usage unless I'm missing something. It depends on if you would ever hit terminal velocity during Mars descent. If no, then coming in from a lower trajectory would allow you to slightly reduce Mars landing burn fuel requirements. If yes then there is no difference unless for some reason you can't brake into Mars orbit via aero alone, which, should be possible unless you're absolutely screaming into the system on an accelerated transfer.

I could see it for bulk refueling. If they actually do get to the point of doing a Mars flotilla, they only get 1, maybe 2 shots at each orbital plane per day per launch site. If all of the Mars ships are in the same orbital plane for transfer and convenience reasons, doing only 1 launch per day would be effectively wasting half of their propellant throughput.

During the time the forum was dead, I watched a wonderful YouTube video about the rarest moves in Chess notation. That got me wondering what the rarest parts in KSP were, and I got the idea of making a Python script that would download every craft from KerbalX and add up all of the parts. Unfortunately, interfacing with another site and trying to not spam KerbalX scared me a little, so I scaled it back to just something that would look through craft files and tally up the stock parts. The hard parts involved figuring out which parts were stock, filtering out any craft included in the game, and the game using like 3 separate naming schemes and using underscores in some places and periods in other places. Eventually I found (hopefully) most of the bugs, and set it loose on my large collection of KSP save files spanning probably nearly 10 years of gameplay. The current implementation does not count DLC parts and it does not deal with repeats caused by copying over saves when copying over installations, so the methodology isn't perfect, but here are the results: Barring methodology errors and saves on other computers, the craft I have built in KSP total 996,968 parts, or very nearly a million! As for my most used parts: Unsurprisingly, the strut is the most common part with 73k uses, especially as many of these craft predate autostrut, and there are still some things autostrut can't do or can't do very well. The sepratron is in second with 42k uses. For an average player this seems very high, but this is likely because I do a lot of things with stock part combat. Each missile typically uses 2-8 sepratrons, each craft carries a LOT of missiles, and I built a lot of these craft, some of which got copied over through multiple installs and some of which had several revisions saved under different files. Add this on top of normal sepratron usage and sprinkle in a few meme craft with a few hundred sepratrons each, and you get a lot of them. The 2x2 structural panel occurred 20k times. This number is likely inflated by 2 atypical use cases. Firstly, it is armor for the stock combat ships. Secondly, I (used to) do a lot of mission reports involving building sets and taking screenshots of them, the 2x2 panel was a good part for that, in addition to the wing parts. Launch clamps have 19k uses. Not surprising, though also inflated by sets. Cubic octagonal struts have 17k uses. Not surprising, those things are handy. Small static solar panel 16k uses, also not surprising. Interestingly my most commonly used SRB besides the sepratron is the Thumper at 16k uses. It is a convenient form factor I guess. IDK what I expected but this tracks. The Vector engine I'm not surprised by with 15k uses, it is probably my favorite engine and I build a lot of very big ships that make use of clustered Vectors. To go along with it, the large 3.75m fuel tank has 14k uses. The fuel line is at 12k, unsurprising, especially as many of these craft predate the new fuel flow control system, and that can often be more clunky to use than the fuel lines so I still use them often. I'll stop listing every single one here, but some interesting ones: Most used aero piece: AV-R8 Winglet at almost 12k, just barely eclipsing one of the rectangular wing pieces Ion and Nuclear engine have 9k and 8k uses respectively Somehow I've used over 1000 fuel cells. Likely only for memes or as aesthetic parts, or from my experiments into ion planes back in like 1.1 or 1.2. Now for the least used parts: Four parts I've never used at all! Those are the ESA BepiColumbo probe parts and the 1x5 solar panel parts. I'm very surprised that I haven't used the probe parts as greebles at all, but I'm not surprised I never used them on a mission. And I'm very surprised I haven't used the 1x5 solar panels at all. I didn't think I'd use them often, but never once? The small fireworks launcher and one of the navigation lights have each been used once. Fireworks makes sense, if I'm gonna do them I'm gonna use the big ones. Nav light, generally when I use the lights it is so that I can see, and I gravitate overwhelmingly towards the original 2 lights in that case. The stack tri coupler I've only used 3 times. I'm very confused at this. That's a part that has been in the game since 0.7.3. It is the most classic "feels like KSP" part from that era. And I've only used it 3 times??? Granted it isn't a very convenient part to use for modern designs, as it was built for a time when you couldn't attach fuel tanks radially and long before 2.5m parts. But only 3 times???????? One of the EVA storage containers has only been used 5 times, unsurprising, I only ever use those to store tire repair kits and 90% of the time I just repair wheels with the debug menu anyway. Another new light at 9 uses, and the large fireworks at 9 uses - I haven't played around with the fireworks nearly enough. The reliant engine has only been used 13 times according to this list. This isn't that surprising as I just straight up use a swivel if I need an engine in that class. But it might be misleading as the engine did get redone in like 1.11 or something, I forget. The internal name may have changed, so this may not be counting it properly. There's other interesting stuff too, like how the Infrared Telescope has been used 19 times, but I can tell you that I've only actually used it for its intended purpose once if I remember right, the rest are because it looks cool. Or how I just don't use stack separators or n-couplers/n-stack adapters very often. Or how like somehow I've used the utterly useless avionics nose cone 79 times, more than several dozen other parts including the magnetometer. But you're welcome to go through the list and make some conclusions yourself! Just be aware that several parts have had new versions made, their internal IDs may have changed so this may not be a perfect list. I might also clean up the code and release it so you can run this on your own saves, or maybe you can send me your saves folder and I can run the analysis for you. Or maybe I'll get around to making the full version that can scrape every craft on KerbalX.

Crew-10 in February is using a brand new Dragon, likely the last one they will build unless Starship encounters insurmountable problems, so we will get a new spacecraft name in a few months.

I guess being unemployed and not in education has its benefits. Watch party it is.