Main Engine Cut Off - T+204: ISS Port Management (with Bill Spetch of NASA)

Episode Date: December 14, 2021

Bill Spetch, Manager of the ISS Vehicle Office at NASA, joins me to discuss the operational considerations of docking and berthing ports on the International Space Station, the recent traffic jams we���ve seen on station, why certain vehicles and systems use one port over the other, how to fit large cargo through docking ports, and what the future of ISS port operations look like in the era of commercial space station expansion.This episode of Main Engine Cut Off is brought to you by 40 executive producers—Brandon, Simon, Lauren, Kris, Pat, Matt, Jorge, Ryan, Donald, Lee, Chris, Warren, Bob, Russell, Moritz, Joel, Jan, David, Joonas, Robb, Tim Dodd (the Everyday Astronaut!), Frank, Julian and Lars from Agile Space, Tommy, Matt, The Astrogators at SEE, Chris, Aegis Trade Law, Fred, Hemant, Dawn Aerospace, and seven anonymous—and 712 other supporters.TopicsNASA OIG, AUDIT OF COMMERCIAL RESUPPLY SERVICES TO THE INTERNATIONAL SPACE STATION, April 26, 2018It now seems likely that Starliner will not launch crew until early 2022 | Ars TechnicaSpaceX crew capsule relocated outside space station before Boeing mission – Spaceflight NowThe ShowLike the show? Support the show!Email your thoughts, comments, and questions to [e-mail] @WeHaveMECOListen to MECO HeadlinesJoin the Off-Nominal DiscordSubscribe on Apple Podcasts, Overcast, Pocket Casts, Spotify, Google Play, Stitcher, TuneIn or elsewhereSubscribe to the Main Engine Cut Off NewsletterBuy shirts and Rocket Socks from the Main Engine Cut Off ShopMusic by Max JustusArtwork photo by NASA

Hello and welcome to Main Engine Cutoff. I am Anthony Colangelo and today I have Bill Spech of NASA with me to talk about some ISS related topics. Bill is leading the ISS vehicle office right now at NASA. He previously spent time at the Transportation Integration Office, time on the Commercial Cargo Program, and time on the Commercial Crew Program as well. All different aspects of the ISS. But I've got Bill on the show because I've got some things to hash out about the docking and berthing port situation on the ISS, some of the traffic management around those decisions. We've seen some traffic jams on the ISS lately and kind of wanted to get a sense for some of

the technical questions that are out there about which ports can be used for which vehicles and what things can fit through which ports, stuff that we've heard in the past, but I just got some stuff that I want to hash out after seeing some recent traffic jams. So it's going to be an awesome time to get some questions answered, see if some of the concerns that are out there are valid, see which ones are not, and generally just hope to relax a little more about the state of traffic up at the ISS. So without further ado, let's give Bill a call. All right, Bill Spetch is here with me from NASA. And if I have my notes right, you are the manager of the Transportation Integration Office. Is that correct?

Actually, I used to be. Uh-oh. I had a recent change here where I'm now the manager of the ISS Vehicle Office. And can you give us some background? You had a lot of different roles with the ISS program over the past several years, it looks like. You were involved with the Commercial Cargo Program, the Commercial Crew Program, and now it sounds like vehicles generally. So can you give us an idea of what those different teams are doing on any given day? Yeah, sure. So I started off actually doing systems engineering and integration, doing integrated performance for the space station

itself, mainly working on the electrical power system and a lot of the positioning for the solar arrays and things of that nature when we had vehicles coming in. Back in 2013, I transitioned over to the Transportation Integration Office where we, and then the commercial providers, SpaceX and what's now Northrop Grumman. And then we also worked as the key integration focal for the ISS program with the commercial crew program and making sure that we got all of our requirements straight between the two programs for those vehicles to come and visit the ISS. So it's perfect. I'm lucky that they picked you to talk to me because when I contacted the ISS PR department, basically, and was asking some weird questions about berthing and docking ports and some traffic management, and they found their way to you, which sounds ideal. And the reason that's been on my mind lately is the past several months, as we've seen the initial CRS-2 flights from SpaceX that use the newer version of Dragon that docks to the space station rather than the old Dragon which birthed. There was a couple of moments of a little bit of a traffic jam where we had a couple of crew vehicles going up, then you had a cargo Dragon, Starliner was on the manifest for a

bit there, and it just seemed like there was a lot of management on what is in what port, when, and when can they be up there, and how long can they be up there. So it got me thinking about, we basically have two docking ports and two berthing ports on the station right now. And it was a lot simpler when it was just cargo vehicles to the berthing ports, and then crewed vehicles to the docking ports. Things have gotten a little bit different since then. So to start, maybe, can we just talk on a technical level about the differences between the docking and berthing ports, the sizing concerns there, and some of the functionality that we get out of each? Yeah, sure. So the docking ports, when compared to the berthing ports, you're right in the differences.

The docking ports in general are smaller. So there's a smaller diameter hatch for us to get items through. diameter hatch for us to get items through. But it allows us to get those vehicles attached without having to use the robotic arm. So the big thing with the birthing ports, while we get a larger hatch that we can go fit bigger things through, it does require the arm to be available to us. And that then also creates additional time that has to happen within those operations before you're fully mated. And so when we, the, one of the key differences between the docking and the birthing is our ability to get off the station faster and how quickly we can close the hatch.

And then how long does it take to get released and get whatever vehicle home? Um, and then how many constraints do we have? How many different launch commit criteria do we have to be able to do that? And so the arm is a big piece of that. It's been very reliable. It's a great system provided, but it is another mechanism that you have in the path of getting a vehicle attached or detached. And so, yeah, you're talking about the, in terms of the constraints on timing, would be not only what is the arm doing

at any given moment on the station, but also the crew time involved, because there's at least one or two crew members that would be actively working with the arm, monitoring stuff. So are those constraints from a planning perspective? Was this more of one of those cases where it's easier to have

something dock because that is really up to the vehicle itself at that moment to run through its whole workflow? Or what is the real crunch there? So the biggest thing is you want the crude vehicles to dock, right? Because we want them to be able to get off and get on without being reliant on those other systems necessarily, especially for emergency cases, right? Just to name something that we haven't had to worry about in recent weeks on the ISS. Exactly. But we set it up that way so that it's really focused on the crew vehicles. Now, the interesting thing with Cargo Dragon 2 is because it has a lot of similarities to the Crew Dragon,

so that allows us to actually test things out on a cargo vehicle before it gets implemented on a crew vehicle. So that was one of the advantages that we had and that we looked at when we selected the Cargo Dragon 2 in terms of CRS-2 contracts. So that kind of, while it drives a traffic jam, as you've seen in some of these things, there's a lot of advantages that we can go test out. We can learn more. We have more launches. We have more landings all on the same re-entry system, the propulsion system, everything else on that vehicle is the same other than basically the guts of the cargo system. We can test things out. It gives us more experience. It gives us other chances to learn without us having to put those changes on a crew vehicle for the first time.

Now, going back to the original CRS contracts with both Northrop Grumman, we'll just skip all the mergers and everything that led us to Northrop Grumman, we'll just skip all of the mergers and everything that led us to Northrop Grumman, and SpaceX. Both Cygnus and Original Dragon chose berthing ports at that time. Was that something, obviously we didn't have the adapters that we needed up on station yet to actually be able to dock these new vehicles, but was there another reason that berthing was chosen at that time, or was it because that's what most of the station was using for expansion? Certainly the CBM, the common birthing mechanism, is between different models on stations, so you have a lot of time and space with those systems.

Was it just purely a heritage play, or was there another factor there? I think a lot of it was the docking adapter piece. When shuttle docked to station, it was using that Russian docking adapter piece, right? The, the original, when shuttle docked to station, it was using that Russian docking adapter. And we had to convert that then to a more standard one to meet our, our needs on the U S side. And so that was one of the key drivers. We directed them to go that way so we could capture them and birth them there. You know, when we started off CRS one, we had no idea what we were going to get because this was, you know, post-shuttle retirement. Nobody had ever done this kind of thing before from a commercial entity.

So we wanted to make sure that we erred on the safest side possible. When a vehicle is coming up to get captured by the arm, it stays farther away from the ISS and has to hold at a point away from ISS versus coming in and making contact on its own. So it was much, it was a much safer approach from our standpoint for new cargo vehicles coming up. And then as we learned, right, as we went forward, we knew we had to dock crew vehicles. So we developed the docking adapters to go on station and then really set the stage for crew. So we have Dream Chaser coming online within the next couple of years that originally is going to be using the berthing ports as well.

Though I've seen some photos of the module that actually docks to the space station and it looks like that's the hatch inside or the tunnel inside, if you will, is actually much smaller diameter and it looks similar diameter to a docking port itself, less so the berthing port.

Is that kind of, I guess I'm concerned here about the sizing of these things, because I remember in particular, I have one of these Office of Inspector General reports from 2018 that was talking about commercial cargo, commercial resupply. And in there was alluding to a thing that you just said a second ago that NASA selected Dragon 2 for SpaceX's CRS-2 contracts to actually dock cargo vehicles rather than berth. But that limited some of the things that could fit through the hatch. Notably, spacesuits and large cargo bags can't fit through that hatch anymore. And Dream Chasers tunnel looks like it's of a similar diameter. So I'm wondering about that cargo management side, given that Cygnus is the only thing that can fit

those larger items. Is that something that we're concerned about long term? Is it not really an issue because we can still get those items up to station, but we can't necessarily get them back down to ground? So from the Sierra Nevada, the Dream Chaser side, they actually can fit those big bags through both hatches. So as they go through both sides, we can fit those things into the vehicle for return. So from a large item return standpoint, that capability exists. We've actually identified most of the issues we run into on large things returning is how they're packed. And so we've identified the vast majority of items that we were worried about. We're actually able to fit those through the docking hatch, the item itself,

but we can't fit all of the support hardware that goes around it to support landing loads and things of that nature through the hatch. So we developed techniques to actually pack those things in the Dragon vehicle and actually bring them home. So we fly, actually on this next flight, we'll have a spacesuit flying up on the SpaceX 24 mission and returning an old one. So we've actually worked out a lot of cases where we can bring home those large items that we were most worried about in the Cargo Dragon. But then we have to go through a lot of gymnastics with it, and there's limited space within there for those large items. So when Dream Chaser comes online, that opens the door for a lot more of those things coming home. Like you said, we do have the ability to get them up there with Cygnus, and that's a big help. We want to be able to get these large items home to the ground in cases to refurbish them and get them ready to go to launch again.

But if we had to, we can build some of them again ready to go to launch again. But if we had to, we can build some of them again and just launch them and dispose of them if we had to. But right now we've got a really good plan. We've got a good setup with the vehicles that we've got and getting those things through. We're just working through the traffic of making sure we have enough of those large spaces to return them. That's good to hear because I feel like that tidbit was out there that, oh, we can't fit spaces through the docking hatches anymore. And we all were very concerned about it from the outside, not knowing all the details. So it's interesting to hear, you know, where things are at now on that front. Now, you mentioned the traffic management aspect. I'd love

to talk a little bit about the decisions on where vehicles go when they get there and what that planning looks like here on the ground to decide what should fly when. There's certain overlaps between crew vehicles that happen where we're doing direct handovers between expedition crew. And there's certain times when cargo vehicles are on station for several months at a time. I'm just curious what the planning looks like there in terms of, you know, the crew overlaps the easy part, but the cargo overlap is what I'm curious about. Yeah, it's, it's definitely a complicated problem to work through. Of course we had those complications when they were all birthing because you can only have, we can't have a vehicle approach while there's to be captured

by the arm while there's another vehicle on the bottom of the node two module. Even though we could place it on node one there, if there was something there, it gets in the way of capturing that vehicle. So we had those traffic issues even with the two berthing ports that we had. There are a lot of factors that go into it. Obviously, we give the crew vehicles priority. So first priority is we got to make sure we maintain ISS crewed on board. There are other factors that play into it in terms of reach into like the cargo drag and trunk. And, you know, we have certain items that are big enough that they can only go on the top of the Node 2 for

the arm to reach into them. We have items that are smaller that we can actually reach in while that vehicle is on the forward of Node 2. It's happened recently with one of the new solar arrays, right? The vehicle had to move to a certain position to actually have that solar array extracted before spacewalk. I remember that being something that happened within the last couple of months. Yeah, we had to make sure we aligned that cargo vehicle on the top of Node 2, or as we call it, the zenith of Node 2, to be able to reach in there and grab that really large set of solar arrays plus the carrier that it was on and pull it out and make sure we didn't bang into anything. I mean, you're basically describing how docking is superior to berthing in a lot of concerns of the ISS program, where it's less of a constraint on operations of the crew time and of the actual vehicle hardware. So I'm curious what the future looks like.

Do you foresee that we would push for more docking port adapters on the station? We have this whole expansion to the ISS coming up with Axiom that's in the near future that will be adding additional ports. How do you see all that shaking out? So it's going to be interesting. I don't see us adding another docking adapter. We only have the four ports that are basically available to us, two docking, two berthing right now. You know, when we add in the Axiom modules, we're actually going to go down to one birthing port and have two docking ports just based on the traffic management that we're going to go do. And we'll see kind of how the additional ports play out on that in terms of how they get used. Obviously, those will be owned by Axiom, not the ISS program. So we have a plan to manage it. It's complicated to go relocate and change everything

around on the station as much as we'd like to make it look easy. There's a lot of work that goes into that change of docking ports and a lot of things that have to happen. But in the end, that's our best plan forward to make sure that we can keep the vehicles coming up and down. We need the overlap. We want the overlap on the crewed vehicles. And we need that overlap between having a crewed vehicle there and a cargo vehicle there. So that was the best balance that we found within that overall traffic constraint going forward. We do have to do planning. And, you know, when everybody flies on time, it works really easy, right? But like at the airport, right? When flights get delayed,

that's when it starts to get messy and you end up starting to wait for a gate or whatever you're doing. We have the same kind of problems on ISS. We'll continue to manage them just like we do. When things delay, we have a bad thunderstorm in an area and well, shoot, now we have to delay and go figure out what we're going to go do. We'll go replant around those things. We have teams of folks that go do that. Although hanging out at Kennedy Space Center is a lot better than sitting on the tarmac at, you know, Philly International or something like that. So it's not all bad.

I would agree with that. Definitely agree with that. Yeah. So there, you know, there's, there's a lot that goes into it, but, uh, we maintain reserves of all of our supplies to, to handle those kinds of delays. And, and so we keep ourselves covered to, to support all of those things. Now the, uh, I should leave like a pregnant pause in this part in case we want to clip this out, depending on, on how this shakes out. But the, the uh acronym for the new docking adapter on the iss includes the word international uh and i'm curious if that standard is something that i i don't know the full details is already being used on the russian segment of the space station is planned in the future um particularly

i'm asking because nauka that just went up and and now Pritchell that has a whole bunch of new docking ports available on the Russian side. That's a lot of docking ports available. It'd be super cool if one of those had the international system on there that we could send some American vehicles over there and generally have more flexibility between the segments. Is that something that's in the cards? Obviously, there's a lot of political concerns around this and negotiations that have to happen. But just purely from a systems perspective, is there a reason that that wouldn't work in the future? There's a lot of work that would have to go into it, obviously. So those mechanisms are different. They are not set up with the international docking standard

that we based our NASA docking system off and what SpaceX's system is based off of and really what is being tested out for Gateway and use around the moon, which is really the heritage of that system. There are some ads that go in. There are some differences, obviously, with the mechanisms used on Gateway. They have some different needs. But in general, it's meant to be, this is a standard that another vehicle could design to, to come,

come to station. The Russian side, not so much. They have a very strong heritage in their, in their docking mechanisms. They work really well. They're very highly reliable. And I don't see us modifying one of the Russian segment ones because there's there are so many other pieces that then go into play that we would have to modify on the Russian side. And in terms of targets and all the different things that we need from a sensor standpoint to support a different vehicle docking to their their system is set up very much for their vehicles. And, you know, they have the same kind of things that we have to do on the U.S. side. They have to change out crews on their side, so they need a number of ports for that. They have their cargo vehicles that they send up, same kind of traffic model that we have to go deal with on the U.S. side.

So I don't see them changing those things out. That would be a significant cost impact to them. And given where we are in station and station life, I don't see that happening. Yeah, that makes sense. So we'll just keep leaning on Axiom to add tons of docking ports and then hope that they share their space with us. That's what I'll do. I'll call the friends at Axiom and tell them that. We've got a good plan. We've got a good plan with our docking ports. I don't know that we need any additional at this point in time. We've sized the vehicles to get the right traffic flow such that we have timing

worked out. And so I feel pretty comfortable with everything that we've got set up on that. Obviously, more flexibility is always useful, especially in case if something unexpected happens. So we'll look forward to having those conversations with our friends at Axiom as well. Well, you've definitely helped me with some of my concerns and made me feel a little better about the traffic jam. So I'll just enjoy the delays to spend an extra day at the beach, I guess, at Kennedy next time I'm down there. So thank you so much, Bill, for spending a couple of minutes with us. It's been a real pleasure. And like I said, really good conversation with a lot of insight. So thanks again. No problem. Happy to talk. Thank you. Thanks again to Bill for coming on the show. That was an amazing conversation that helped me relax

a little bit more about some things that I was concerned about previously. So that was definitely exactly what I was hoping to get out of the conversation with him. So thanks again for coming on and for everyone at NASA setting this up. It's always special to have people from the ISS program on the show to talk about this stuff directly. But before we get out of here for the day, I want to say thank you to all of you who make this kind of thing possible. There are 752 supporters of Main Engine Cutoff over at mainenginecutoff.com support. And I could not do it without each and every one of you. And this episode was produced by 40 executive producers. do it without each and every one of you. And this episode was produced by 40 executive producers.

Thanks to Brandon, Simon, Lauren, Chris, Pat, Matt, George, Ryan, Donald, Lee, Chris, Warren, Bob, Russell, Moritz, Joel, Jan, David, Eunice, Rob, Tim Dodd, the Everyday Astronaut, Frank, Julian and Lars from Agile Space, Tommy, Matt, the Astrogators at SCE, Chris, Aegis Trade Law, Fred, Haymonth, Don Aerospace, and seven anonymous executive producers. Thank you all so much for making this episode possible. And thank you to all the supporters out there. And I'm going to talk about this more in a special episode on the podcast at some point this week. But this week is my last week at my full time job. For those who don't know, I've been working at a full time job for all these years. But starting in on Friday, I will be totally independent to be able to spend more time doing Nico more time doing off nominal, the other show that I do with Jake Robbins. And it's going to be an

awesome time. I think it's really going to help the show grow into new areas and to do a lot more with a lot more energy on this stuff. And I could not do that sort of thing without all of your support. So again, I'm going to go deeper in this on a special segment of the show and not just put it in the outro of a show. But I just wanted to say thank you to all of you. You're making this kind of thing possible. I can't wait to tell you all about it. And I will do that next time on the show.

So until then, thank you all so much for listening, for your support. And I'll talk to you soon. Bye.