Russia's New Space Station Module Causes Alarm On ISS

hello it's scott manley here yesterday the russian multipurpose laboratory module also known as nauka finally reached the space station and docked after what cannot be described as a trouble-free journey and furthermore very soon after arriving resulted in a kind of emergency on board the space station but we're going to talk about that later but first of all i want to talk about the problems that nauka had immediately after launch and getting to the space station so the launch on the proton rocket went exactly as planned yes proton is ugly and i know many if you don't agree with me but it is a great launch vehicle and it put the spacecraft into its target orbit correctly but as soon as they started testing things out there were a number of problems most of them were not immediately problematic they had problems with docking antennas and docking targets there was a problem with one of the the infrared horizon trackers where they have a hardware that can look for where the horizon is the spacecraft can orient itself relative to the earth they were able to circumvent that problem or work around it by using star trackers and other navigation information but the biggest problem was they were getting some bad readings from the propulsion system which is pretty important because they needed that to raise their orbit and begin their rendezvous with the international space station they could only spend a few days in this low orbit before they would lose access to the space station so naoka comes with three different propulsion systems one is the dks right those are the main engines they are a turbo pump based engines that generate about 400 kilograms of thrust there's the dps which are the attitude control thrusters and there's also a third attitude control system that's only used when it's docked to the space station that's the mddk cluster those are provided those are there to provide extra roll control for the station because the module sits so far down from the station that it has really good lever arms so they decided that they wanted to put roll thrusters on there so to get up to the station it's supposed to use its primary thrusters the dks and since those are pump driven they are fed from the low pressure fuel system that's the main propellant tanks so there are four propellant tanks these are long thin cylindrical tanks are on the outside of the module they're also behind white panels that are radiators there's two oxidizer tanks containing nitrogen tetroxide and two containing fuel in udmh and but they're designed for zero gravity so inside the liquids are contained inside flexible bladders or bellows and when you want to take fuel out you inject gas in outside the bladder and it squeezes it and you only get liquid out this is great and there have been a few news reports expressing some concern about the state of these bladders there are some places that say that these have ruptured i don't believe that's what happened that's what the current information suggests but you know it's all rumors and leaks coming from people rather than official sources and i have to give a huge amount of credit to anatoly over at russian space web who seems to be the person that always has his finger on the pulse and all the best leaks so yeah check out russian space web if you want to get the the lowdown on any of this now there's also a series of high pressure spherical pre tanks that are designed to feed the reaction control thrusters those reaction control thrusters are smaller they're simpler they don't have pumps so they work best when they're fed much higher pressure uh propellant now both these propellant systems are interconnected it's possible to pump low pressure fuel to the high pressure system but it sounds like early on in orbit there was a software error which resulted in high pressure gas going into the low pressure system and that's problematic because those main engines are designed to have pumps that operate at certain pressures so if the pressure inmate said that the low pressure tanks got above seven atmospheres then those main engines couldn't operate so it took them a while to figure this out but they were in a position where they couldn't fire the main engines and so they had to start firing the dps the reaction control thrusters so that they could reduce the pressure on the main propulsion system and that's what they began to do early on the first maneuvers were all carried out by the pressure fed engines and once the pressure got low enough they began to be able to use the dks engines to maneuver them towards the space station but they got off to a late start and that caused problems because when you're trying to rendezvous with the space station you have to launch into the same orbital plane because it's very cheap in terms of propulsion to raise the orbit up in terms of its altitude it's much more expensive to change the plane of your orbit turn it if your orbits become misaligned and as you're orbiting the earth the earth actually continually changes the plane of everything in orbit that's close to the surface it's it's as a result of the earth having a larger equatorial radius than a polar radius and that means the earth is a bit fat around the middle and that pools on the orbits and causes their plane to process around by a few degrees every day i call this fat earth theory anyway the rate of this rotation depends upon your altitude and since naoka was at a lower altitude it was precessing around the earth slightly faster than the international space station it turned out to be going out of plane by about half a degree per day so the longer they waited the more propellant they would have to spend correcting this either that or they could boost themselves up to a higher orbit and then let the iss catch up but either way they would use more propellant the longer they waited so ultimately this delay and using the less efficient dps thrusters meant that they probably didn't have enough fuel margins to make more than one rendezvous and docking attempt but the good news is yeah they got the vehicle under control they managed to set up a rendezvous they were go for docking and that means the the space station had to prepare so the first thing they had to do was remove the old piers module it was attached to a progress spacecraft to undock they actually had to flip the space station into an unusual orientation where the bottom of the station was facing backwards along its orbit so that as the progress spacecraft pulled backwards it would have a direct exit out to lower orbits and ultimately to ditching it in the ocean there were a lot of concerns that having two spacecraft docked in space for 20 years could result in the docking system sticking so they actually had some extra hardware to push them apart turns out they didn't need that afterwards they needed to perform an inspection of the port and they did this using the remote manipulator arm the canid arm on the space station the way i actually got to do this is kind of interesting not a lot of people realize the arm on the space station is double ended both ends are the same and so they can take one end the normally free end of the arm move it across to a power and data port on the zarya module connect it there and then lift off the normal route node and then they use that end to go over and inspect the port and they found that there was no problem there there was concerns that they might need to perform an eva to go out and scrape off any deposits left behind but the port looked clean so they were go ahead for docking and again it had to assume an unusual attitude for this maneuver they had to yaw the station 180 degrees so the international section was at the back and then pitch the whole vehicle around so that the bot the traditional bottom of the station with the port that nauka was going to dock at was pointing backwards along the orbit zarya or and zvezda or the russian segment were on the zenith pointing towards the earth and the international section was towards space and that was because the crews automatic docking system expected this attitude or worked best in this attitude and yeah you know the docking was slow considered at the last few minutes there are last few moments there was some concern they might have to switch over to the toru um you know manual control system like 40 meters of mission control in russia were telling them to switch over but then the system quickly corrected its misalignment and the docking finally completed and hard capture happened i think it was around 6 15 moscow time and so we expect that was the end of the real excitement for the day they were going to go in and open up the hatch and get into the module and integrate now into the space station control systems and it was while they were integrating this into the system that something went wrong and the astronauts and cosmonauts got a loac alert a loss of attitude control this was just after space station sunset as it was passing over west asia in range of many other of russia's control systems and again according to people in the know uh it sounds like the spacecraft had somehow had a software issue and had decided to start backing away from the space station so it was flying as if it was on its own but it was pulling the whole space station around with it so instead it was resulting in a rotation the space station's control systems began to try to counteract this initially it would have used control moment gyros probably but the next thing would be the reaction control thrusters on board this vista module at the back those turned out to be inadequate and so the russian controllers in russia started up the progress spacecraft ms-17 which was docked to the nadir port and its thrusters were able to stop the rotation and bring everything back under control now the official nasa word on this is that they moved 45 degrees out of attitude and that's what's being repeated i think that's wrong i think that's a definite underestimate that is what i heard over uh you know station to ground communications but they also said straight after that the rates had stopped increasing and but they were still moving so they were rotating at about half a degree per second for a lot longer than the 90 seconds it would take to move 45 degrees this is a video captured from um a youtuber who does live streams showing space station status and looks at the earth from space and in the bottom right corner they actually have like telemetry or data that they can get from the space station it's publicly available and if you look very carefully at those numbers in the bottom right that are flashing yellow you'll see that the pitch rate is about half a degree per second and that persists through the entire duration of this video and indeed the emergency continues after the video feed gets cut but what you can see here is the illuminated horizon of earth from two different cameras and you can see it moving across sweeping across as the station rotates these are fixed cameras now the communications described this as a tug of war between the reaction control thrusters and a lot of people asked well was the station in danger of being torn apart by these rocket thrusters fighting each other and the answer is no the thrust from these thrusters is like hundreds of kilograms at most the pressure across each of those your station boundaries you know the docking modules are like you know tons because the air pressure is high the structural integrity of the station is way higher than these tiny thrusters can overcome but there is a danger when you have multiple thrusters working and a set of thrusters which are not integrated into the station's control system they could they pulse and if they pulse at the wrong frequency they can set up resonances they can make this station wobble and those wobbles can introduce like transient loads which are beyond what the station could handle this has happened in the past and it's something you definitely don't want to have happen fortunately it didn't happen in this case if there was an emergency the dragon spacecraft which brought four of the crew up was powered up prior to the docking because the docking's considered a safety critical situation the shutters were already closed prior to this but they opened them up to look at now can then close them when the emergency started progress sorry m soyuz would probably also be powered up as well in anticipation of it if it possibly being needed as a lifeboat thankfully that wasn't necessary everything was brought under control and it looks like the space station has returned to normal attitude after uh this whole operation there were some reports that said the nyoka only stopped firing its engines because it ran out of propellant that may or may not be true but they certainly have very low propellant uh loads left and it sounds like they're not sure whether they want to actually try to purge the system and clean out all the toxic corrosive propellant or just fire the pyrotechnic valves to close off all the propulsion systems so they can't be used so as i said nauka has three different sets of propulsion systems and the the dps and the dks which were used for orbit maneuvering those are going to get isolated from the propulsion system permanently and irreversibly and all that will be left is the roll control thrusters which will be used for the iss and those will draw fuel directly from the rest of the russian section the fuel system isn't going to be entirely isolated because when progress docks to nauka they have to be able to take propellant from the progress and feed that into the main uh tanks on the space station for refueling another consequence of all this excitement is that boeing has had to cancel their starliner launch which was planned for today uh it's probably going to get out on the next launch but yesterday there was a lot of uncertainty about what state the space station would be in today turns out that uh yeah i think everything's going to be fine and starliner will probably get away for its launch and demonstration so that we can actually have you know some sort of redundancy in u.s space launch capability and by the way starliner lot not launching that means that this is the first month in a very long time that us has had no orbital launches um although i guess rocket labs sort of as a us company but it launched from new zealand and yeah i guess virgin galactic and blue origin both doing sub-orbital flights with humans got plenty of space activity in the news in the us so yeah uh everything looking fine on the space station it was a little hairy it will be something i really want to read the the actual reports on later i'm scott manley fly safe [Music] you

Channel: Scott Manley

Views: 574,036

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Id: jTR5evpFLb4

Length: 15min 57sec (957 seconds)

Published: Fri Jul 30 2021

Reddit Comments

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This is a fellow kids moment ngl

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Kind sus ඞ ngl