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We have one. Not, however, one in a good orbit. Or one that can be used as a fuel depot.
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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We have one. Not, however, one in a good orbit. Or one that can be used as a fuel depot.
That statement is incorrect. As pointed out by others, the ISS is below the Van Allen belt radiation, and sufficiently close to Earth to receive some shielding from GCR; the GCR exposure is ~ 50% attenuated. It's located at a point where a delta V of 3.4 kps will get a Hohmann transfer to Mars. That's good enough for present technology to enable deep space missions.
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ISS has adequate altitude, but an unfavorable inclination. Something just a smidge higher for nearer 23 degrees inclination would be better. The old 1940's proposals for 1000 miles altitude predated our knowledge of the Van Allen Belts. Anything under about 800-900 miles would be OK. Space debris pretty well restricts us away from 600 miles.
ISS will be worn out and increasingly dangerous for its crews after about 2025-ish. The time is now to think about how to replace it, and by whom.
Folks like Bigelow are hoping to replace its function before it gets abandoned and deorbited. Even if our idiotic Congress mandates that destruction prematurely for budget-cutting "logic".
They very well might. Ideology sucks.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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GW-
Do you have any idea as to how much $$$ has gone into the ISS? Construction? Maintenance? Rides to and from? I can't seem to get a handle on it, but when the ongoing Space Shuttle trips to orbit were ~ $500-600 Million each, this "investment" has been excessive. It's certainly still eating a substantial portion of the NASA budget annually.
Maybe we can get an original von Braun "bicycle wheel" to replace it? We need to really consider the next SS as an orbital refueling point, and not just a "place to go."
Onward and outward! To Mars and beyond!
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The ISS is aging but its not a dump heap its a highway to the rest of the stars that much like the roads on earth need maintanance replacements of the oldest of modules to keep it in use. To which the direction needs to incorporate more than just science work as we need to begin bilding the path outward from it.
The use of a lunar lander with a ascent stage that has hydrogels for fuels and a descent stage that is mathane insitu refilled is ideal for mars but it may not be possible for the moon. To which we would dispose of the descent stage and only reuse the ascent stage if brought back to the iss.
We should use the moon as a design lab for a mars process and for its conditions let alone the durations.
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In 1968 NASA wrote a document outlining their vision of the future. It included a space shuttle, and space station at 400km altitude @ 50° inclination. ISS today is at 400±10km @ 51.6°. That's so close to where NASA wanted to put it that the difference is not worth mentioning. The difference was for the Russians. The Baikonur Cosmodrome is at 51.6° latitude, and you can only launch to an inclination the same or higher. So the Russians can barely reach ISS. This also means the lowest inclination you can reach from KSC is 27.5°. To reach an orbit lower you must first launch to an inclination that equals your latitude, then make an on-orbit inclination change. An inclination change takes a hell of a lot of propellant; you really don't want to do that.
ISS has cost a hell of a lot of money. Including research, development, construction, upgrades and operation, it's cost $100 billion! There's no way you could justify another station. There's no way you could justify decommissioning it.
Yes, we could have built a better station. In the 1970s NASA proposed an international space station built in exactly the same location as NASA's 1968 proposal, which is practically the same as it is now. That station would consist of 2 Skylab workshops launched wet, an airlock, and a multiple docking adapter. 4 launches of Saturn 1B, from start of construction until US core complete: 6 months. And it would have had more interior volume than ISS today. And each Saturn 1B cost less than a single Shuttle launch. It didn't happen. Would-a Could-a Should-a. And we can't do that now because we don't have Saturn 1B. Today's launch vehicles don't have a large upper stage that could be made into a Skylab workshop. Besides, engineers today don't want to even consider station module that launches wet. That's far too advanced. That's a skill from the age of Apollo that today's generation just simply doesn't have, can't do, and just doesn't want to learn. Try talking to a current engineer, describe a self-launching space station that launches wet, but don't use the name Skylab. He'll tell you it can't be done, would never work. But Skylab did work. No excuses, it did work. NASA has lost a lot of capabilities, this is just one. One reason engineers are so timid is their managers.
If we don't have a 6.6 meter diameter stage that launches wet, or something even larger, then forget any new station. There was one proposal to do it with the upper stage of SLS block 1B. That could deliver 105 tonnes to LEO. Saturn 1B could deliver 20 tonnes to LEO. There is no comparison, SLS is not even close to cost effective. Current mid-size launch vehicles are Falcon 9 (not Heavy) and Atlas V. They have 3.7m and 3.05m diameter respectively.
Last edited by RobertDyck (2017-06-30 22:53:36)
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I never said I wanted to see the ISS decommissioned, I said (in so many words) that Congress or the administration might force its decommissioning.
What I said was that it will eventually wear out to the point of endangering crews, like Mir and Salyut before it. That cannot be avoided.
Either way, it will eventually need replacement. And as I have often pointed out, one of the two drivers for its $100 B+ cost was the expensive space shuttle at $1.5 B per launch, at end-of-program inflated dollars. The other driver was first-time-up learning curve effects.
ISS is a bunch of modules docked together at 15 tons or less apiece. There is no way in hell you could not launch 500 tons of space station today with Atlas-5 or Falcon-9 in 15 ton chunks, and dock it all together for a price closer to $10 B than ISS's $100+ B. That is because those launchers are more than 10 times cheaper than shuttle, even if you launch the very same modules.
You need not launch the same modules. You could send up far fewer Bigelow B-330 (not BEAM) inflatables and get even more internal volume than with ISS. Customize them with fold-out internal decks, and you could dock them together into a baton and spin it for artificial gravity. I saw enough on Bigelow's site to indicate they could easily do that.
And don't complain to me about radiation in an inflatable, based on what they are seeing with BEAM. Beam has half the hull thickness of B-330. BEAM was designed to have similar protection to an ISS module. B-330 should be about twice as good, good enough for ISS-like exposures at the moon or Mars.
And don't complain about BEAM being the first-ever test of an inflatable. No it is not; there are two Bigelow test prototypes still up there right now. B-330 was based on those results, a project NASA did not participate in, and knows nothing substantive about.
BEAM's real purpose was to bring NASA up to speed with something simple, so that they would overcome their NIH attitude and buy something much more sophisticated from Bigelow in the near future.
NIH = "not invented here". Bigelow's inflatables are way beyond the NASA trans hab they derive from. Pure and simple.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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For anyone who wants to build a new space station, I have the ideal location. The surface of Mars!
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I agree no fancy inflateables no 40 mt vehicles to land ect... we have the technology to go but its not going to be done without preload of supplies and more at the landing site, its going to be with orbital sub assembly of parts but its going to be with investors wanting to pay from there own funds for R&D and for vehicles to make it happen. There will be no gravy train of contract plus for failure to provide at a reasonable cost.
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SpaceNut,
It's not about the tonnage of the vehicles at this point, it's about how much money we want to devote to the tonnage of the vehicles to accomplish the mission. Rockets like Falcon Heavy, Vulcan Heavy, and New Glenn can affordably deliver whatever tonnage is required to ISS, which is the real jumping off point for interplanetary exploration. The L1 gateway can be a usable jumping off point if robotically operated SEP tugs drag the spacecraft out that far to reduce the dV requirements of the kick stages. One way or another, the dV requirement has to be satisfied. If you want a half dozen to a dozen astronauts to go to Mars per mission opportunity, then you can split them into pairs so that a single rocket can deliver them and everything else required to support them to Mars orbit aboard a single spacecraft. Whatever is required for survival on the surface of Mars must have been pre-landed in the previous cycle or at least delivered to Mars orbit.
If NASA wants to use SpaceX's ITS, then they can safely deliver a dozen people to the surface of Mars without pre-landing anything because ITS can go from the surface of the Earth to the surface of Mars and then back to the surface of the Earth using the same vehicle. Using LOX/LH2 instead of LOX/LCH4, it must refuel twice in LEO and once on the surface of Mars per mission. My conjecture from another thread is that using 7 RS-25's in the upper stage of the vehicle reduces the mass of the spaceship to 1,000t from 2,500t and the size of the vehicle is about the same as the original concept from SpaceX to provide equivalent performance using substantially less fuel mass.
If the Sabatier reaction is well proven technology for providing LOX/LCH4, then water electrolysis is equally well proven for providing LOX/LH2 and requires simpler, lower-cost, and lower-mass technology. There's enough of a fuel mass and engine performance advantage to warrant a detailed design analysis. I think it's the best fit for this mission class, but I could be wrong. Land on your water source, drill into the iceberg, pump the water into tanks aboard ITS, distill the water, electrolyze the water, and then pump the O2 and H2 into the fuel tanks after it's run through a cryocooler.
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kbd512-
I respectfully disagree with you re: using the L1 point as the departure point. I'm fully in agreement with GW that LEO makes most sense. It avoids unnecessary complications of additional orbital transfers, is below the Van Allen belts, and is close enough to the Earth and within the magnetosphere to give attenuation to GCR background exposure.
Yes, (l) H2 and LOX are seductive, w/r the Isp; unfortunately the deep cryogenic nature of H2, which is also very low density, and thus requiring heavier insulated tanks which are much larger than those required for CH4. As reactions go, the Sabatier reaction is elegant, and once started, is self sustaining s long as feedstock is available (it's significantly exothermic).
I'm convinced that SpaceX will ultimately reach the same conclusion as I have, and an intermediate launch vehicle for early exploration is needed--between the Falcon Heavy and the ITS. Something they published earlier about the Falcon X and Falcon XX.
Last edited by Oldfart1939 (2017-07-03 08:14:52)
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Which sort of brings me back to a safety net of the hydrogel fuels to which can the same engines be used or are there a batch of modifications needed to make use of it should we have issues with insitu methane creation on mars. Would man be able to deal with the switch over once on mars.
There seems to be methane vents but until we explore them we will not know if we can get enough fuel from them.
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Ultimately, radiationally speaking, GCR isn't the lethal threat, solar flares are. Having the ISS below the van Allen belts helps protect it from solar flare radiation without having a specifically-designed shelter. If you put a thing like that outside the Earth's magnetosphere, then you must provide a flare shelter. 20 cm of water works. But it's heavy, unless it's made of stuff you have to have with you anyway (like water, wastewater, and frozen food, even propellants).
Any stations we put into orbit about the moon and Mars (and any orbit-to-orbit human transports) will have to have such a flare shelter. There is no way around that: for voyages measured in months and years, the odds are in favor of getting hit by such a thing, not against it.
GCR is really just a long-term health risk (and anything that attenuates it is good, of course), but the immediately-lethal event is the unpredictable flare. Not enough attention has gone to that distinction. Certainly not in most of the vehicle and habitat designs I have seen proposed.
This is a thinking box left over from Apollo. Because those missions were under 2 weeks long, the odds favored not getting hit by a flare while out in space or on the moon. We got away with it. But there was a 1972 flare event between two missions that would have killed an Apollo crew in a matter of a very few hours. And it's an ugly death.
If we go anywhere out there for long trips or visits, even returning to the moon to stay, then the lethal flare event must be planned for and addressed properly. I'm sorry, there is simply no way around that ugly little fact of life.
The time to plan for it is when your mission architecture is first formulated, not as a band-aid after-the-fact. After the fact is always heavier, costlier, and completely inconvenient in just about every way.
GW
Last edited by GW Johnson (2017-07-03 09:17:06)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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If everyone recalls--Robert Zubrin addressed the Solar Flare possibilities in Case for Mars, and also in Mars Direct. This was one of the reasons he encouraged the use of whole foods and not dehydrated foods--use of the onboard food supply was to assist in building protection from Solar Flare radiation. The inherent H20 content provided a lot of the required shielding.
As GW has repeatedly pointed out. there must be a flare shelter incorporated into any structures outside the VABs and magnetosphere. This makes the recently NASA proposed "Deep Space Gateway" appear incredibly stupid, as are proposals at various Lagrange points.
It seems that the once Bright Lights at NASA have all departed to private industry, leaving the old dimbulbs behind?
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The whole food for return trip then is problematic n that we will need to bring them back up from the mars surface that we have grown....Which means cargo landers will need to become refuelable to be able to launch back to orbit with that commodity....
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I was able to size and show feasibility for a 1-stage chemical landing boat for Mars that used somewhat-conservative structural mass fractions, and even MMH-NTO storable propellants. Its only "problem" was a 3% dead-head payload fraction. If you deliver 2 tons, your ignition weight is around 65 tons. Even that's no problem for a retropropulsive final landing under automatic control.
Other propellant combinations with higher performance lead to larger payload fractions. But the point is, one-stage round-trip chemical landing boats are indeed feasible with rocket technology we have had since 1960's and heat shield technology we have had since the 1980's. I did my calculations carrying that payload both ways!
As to whole foods as a shield, you need it on the outbound voyage. You also need it on the return. If you do an orbit-to-orbit transport, then just put enough aboard for the round trip. Leave that in orbit! You should not count on an excess of food grown on the surface for your return, not on an initial exploration mission! If your greenhouses do not work, the crew starves on the way home.
Remember, as it says under my signature line, there is nothing as expensive as a dead crew, especially one dead from a bad management decision.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Robert Zubrin's primary reason for advocating whole food was life support technology in 1989/1990. Remember engineers at Martin-Marietta started work on Mars plans immediately after Congress rejected the 90-Day Report. So Robert Zubrin and his partner David Baker, with some support from the other engineers at Martin-Marietta, developed Mars Direct in the last quarter of 1989 and first half of 1990. They gave their first presentation to NASA in June 1990. At that time life support technology could only recycle 80% of water and oxygen, and electrolysis of water is used to replenish O2 losses. I have the first edition of "The Case for Mars", published 1997, I bought it in the spring of 1998. In that book he stated NASA wanted life support recycling efficiency of 95%. Dr. Zubrin argued to go now, just use whole food to replenish water losses.
By the way, current technology on ISS has recycling efficiency of 93%. I have argued to improve that with a toilet that recovers moisture from feces. Russia built a vacuum desiccator toilet before the first module was launched, but NASA was afraid the plumbing was too complicated. I bet they wished they had it after the Columbia accident. And NASA's JSC built an advanced life support project on the ground, which included an incinerator toilet. I have also called for a direct CO2 electrolysis unit to recover O2 from CO2 currently dumped in space. And the water processing assembly can already handle wash water, so I argued to launch the sink and shower that were designed for the US habitation module. And the urine processing assembly got clogged with calcium deposits; NASA is currently working on a fix for that. My argument is launch all that. It should improve efficiency of life support on ISS to equal what NASA said they wanted before going to Mars. Demonstrated it on ISS for the full duration of a Mars mission.
His idea for the radiation shelter was to take everything they would need anyway, everything that had radiation shielding properties, and arrange it around a central radiation shelter. The shelter was located at the centre of the habitat so the mass of the habitat would add to radiation shielding. Great idea.
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quote: His idea for the radiation shelter was to take everything they would need anyway, everything that had radiation shielding properties, and arrange it around a central radiation shelter. The shelter was located at the centre of the habitat so the mass of the habitat would add to radiation shielding. Great idea.
I've met Bob Zubrin myself. Nice to know more than one of us is advocating for "using what you already have as a radiation shelter for flares". Shame that few-to-none at NASA have been thinking that way.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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Still digging for documents to aid in design of mission to land on the moon...
The European Lunar Lander Mission
pg 8 depicts the landing profile which should be quite typical
EDIT:
FLASH-LIDAR BASED TERRAIN RELATIVE NAVIGATION FOR AUTONUMOUS PRECISION LUNAR LANDING
This next one is so space 1999 style of lander
http://images.spaceref.com/news/2009/Re … Lander.pdf
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kbd512-
I respectfully disagree with you re: using the L1 point as the departure point. I'm fully in agreement with GW that LEO makes most sense. It avoids unnecessary complications of additional orbital transfers, is below the Van Allen belts, and is close enough to the Earth and within the magnetosphere to give attenuation to GCR background exposure.
I said that ISS (LEO) is the real jumping off point for astronauts bound for interplanetary destinations, but the L1 destination is just as usable for additional cost. I don't favor this approach, but NASA seems to.
Yes, (l) H2 and LOX are seductive, w/r the Isp; unfortunately the deep cryogenic nature of H2, which is also very low density, and thus requiring heavier insulated tanks which are much larger than those required for CH4. As reactions go, the Sabatier reaction is elegant, and once started, is self sustaining s long as feedstock is available (it's significantly exothermic).
I calculated that the tankage volume for equivalent performance would be equivalent in dimensions to the LOX/LCH4 tankage. The physical dimensions of the oxidizer and fuel tanks would obviously be different, but performance should be very similar. It's a 1,500t difference. That's pretty significant.
I'm convinced that SpaceX will ultimately reach the same conclusion as I have, and an intermediate launch vehicle for early exploration is needed--between the Falcon Heavy and the ITS. Something they published earlier about the Falcon X and Falcon XX.
Perhaps. Time will tell.
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I wonder. Could you replace the upper stage of Atlas V with S-IVB? Saturn 1B was developed by replacing the upper stage of Saturn 1 with the 3rd stage of Saturn V. Saturn 1 could lift 20,000 lb (9,070 kg) to LEO. Saturn 1B could lift 46,000 lb (21,000 kg) to LEO. Atlas V 552 consists of the Atlas V CCB (Common Core Booster), 5 AJ-60A solid rocket boosters, and a Centaur upper stage. The number 552 means 5 metre diameter fairing, the second digit means 5 SRBs, the last means the upper stage has 2 RL-10A engines. That configuration can lift 20,520 kg to LEO. Atlas V 501 can lift 8,123 kg to LEO, and 511 can lift 10,986 kg to LEO. So could you replace the Centaur upper stage with a 6.6 metre diameter S-IVB stage? The purpose is to launch a Skylab workshop wet. Of course that would use modern solar arrays, and modern electronics would have to be installed later. I doubt modern electronics could survive immersion in liquid hydrogen. And parts of the life support system with delicate membranes would also have to be installed later. But walls and floor could be installed when launched wet. And you would use modern multi-layer insulation and thin aluminum alloy bumper shield instead of Skylab's "spring out" micrometeoroid shield / sun shade.
As I posted elsewhere, I found another forum where they discussed a payload this large for Falcon 9. Their conclusion was the core stage gimbals would have to be modified for greater range of movement. Would probably have to do the same for Atlas V. The advantage of Atlas V is that it already uses a LOX/LH2 upper stage. This would just be a bigger one. And it uses LOX/RP1 for its first stage, just like Saturn 1B.
However, I still argue against any new space station. We have one now: ISS. Use that. I argue to add the centrifuge module, and add previously mentioned life support equipment. Other than that, we don't need anything more. The module could be delivered via Atlas V with a Cygnus service module. Equipment could be delivered via any of the cargo ships.
Last edited by RobertDyck (2017-07-04 00:34:36)
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Here is another Lunar Lander Designs for Crewed Surface Sortie Missions in a Cost-Constrained Environment
True kbd512 it is "it's about how much money we want to devote to the tonnage of the vehicles to accomplish the mission." but only when we get all the numbers for all that is happen as all operations costs for this to happen and not what you are charged for that single launch. This is where the standing army of Nasa and contractors come in as to what they can charge.
This is where we get into what is called payload for the launch equation.
Tonnage does matter if you need to cut it up into pieces to bring it to orbit as then we are adding docking and complexity to it....
ISS does correct to tonnage issue but only that we are going with what we can deliver for pieces and are not compromising because we can not launch it as a complete unit requiring it to be broken up into pieces that we can manage.
L1 is not any more of a gateway to space than to being at L2 or any of the other locates where you are getting a free soar orbit being dragged along by the spheres of magnetics. You might as well be in direct orbit around the sun at what ever distance that you want the station at for being a gateway....
Now fuel depots of any of the fuel oxidizer combinations only makes sense when you consider insitu manufacturing of the fuel at the coresponding landing location to which a simular depot is created to sustain flights.
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I would agree with Robert about no new space station--as long as the ISS is safely functional. Considering the $100 Billion investment, it would make financial sense to use it as long as possible.
One of my earlier Mars mission architectures made considerable use of ISS as a staging point for orbital integration of several separately flown modules, with the ISS as a crew preparation area.
Last edited by Oldfart1939 (2017-07-04 08:33:18)
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Yes keep what we have going past the current extension via planned replacement of dated modules with up grades.
Space Station 2024 Extension Expands Economic and Research Horizons
International Space Station gets warranty extension to 2024
The International Space Station’s warranty has been extended to 2024. The announcement, made Wednesday by NASA and the White House, spares the station from being deorbited in 2020 and leaves the door open to keeping it in business through 2028.
Service Life Extension of the ISS Propulsion System Elements
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First Pass Analysis of a White Dragon/Xeus Lunar Sortie Mission using Falcon Heavy and Dragon V2 for an Apollo 8 mission to which Spaxe X has booked.
The flight is short enough relative to a worst-case ISS delivery that with 2 passengers instead of 7, the ECLSS is probably already adequate.
The heat shield, due to minimum gauge issues with PICA-X, is way overbuilt for LEO return, and thus is likely more than adequate for lunar return.
Here’s what the SpaceX stack would look like:
Falcon Heavy
Large LOX/LH2 tanker (~39.4mT of prop, ~7.2mT dry)
Dragon V2 on top
Now for a lunar lander
Falcon Heavy would launch first, placing the crew and tanker in orbit.
Vulcan/ACES would then launch shortly thereafter, with ACES performing a rendezvous with the SpaceX stack, transferring ~39.4mT of prop over (basically filling the ~70mT ACES stage).
The Dragon would then separate from the tanker, and connect to the ACES/Xeus stage. The ACES Xeus stage would do a TLI burn for the stack, followed by an insertion into LLO. Dragon would then be left in orbit while the astronauts are flown down to the lunar surface by the Xeus stage, hang out for a while, and then they get flown back up to LLO by the same Xeus stage. The Xeus stage would then dock with Dragon and perform the LOI burn, sending the whole stack back to earth.
The ULA stack would look like:
Vulcan/ACES 546, with the ACES having a Xeus landing kit (~1mT)
Small short-duration two-person crew cabin (estimated ~2mT)
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