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14 hours ago, kerbiloid said:

Currently the only lunar customer is NASA, and unlikely it will change in SpaceX lifetime.

So, it looks like a dedicated, budget-aimed activity.

USSR was building T-72 for its own needs, no matter if somebody else buys.
Does it mean that the Soviet tank building industry was commercial, if they sold some of them to random customers?

Will the SpaceX lunar things be ever sold if NASA won't buy them (paying from budget)?

Well dear moon is commercial. 

I say this is structural, first organisations like NASA or the military is not supposed to make profit, for the military its even restrictions on this to prevent the officers from using transport aircraft or engineering companies for commercial work. 

Even in an profit oriented company divisions like customer support are not designed to make an profit, even trough they make some money on stuff like premium support or consultant work their main purpose is customer satisfaction and have them stay with company. 

 

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The important distinction is the amount of entrepreneurship, speculation, whatever you want to call it.

Any business builds what they think there is a market for, and F9, Vulcan, NG all fit that bill. From a purely business POV, Starship dev started partially because of Mars, which is NOT a business POV (no plausible business case for Mars), and partially I think because they saw a combination of Starlink launches and future competition from NG as an issue to address. Cargo SS addresses both as reuse makes it cost effective, and it is capable of hauling any larger cargo designed to take advantage of NG's 7m fairing. Since new LV dev takes a number of years, they needed this to happen in advance of NG flying, so that even if NG flew first, they'd follow fast with a superior vehicle.

Getting a large bolus of money from NASA is gravy for SpaceX, but really does stop the others in their tracks. I assume BO goes forward with Blue Moon regardless, and perhaps they try and leverage that for a crew lander at some point.

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45 minutes ago, tater said:

Starship dev started partially because of Mars, which is NOT a business POV (no plausible business case for Mars)

Has tourism for ultra-rich been ruled out?

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16 hours ago, kerbiloid said:

USSR was building T-72 for its own needs, no matter if somebody else buys.

The USSR designed the very complex T-64 for its own needs.  It was only used by them and the best client forces in East Germany and Hungary.  To increase the number of more modern tanks, as well as form a basis for an export model, they also built the T-72.

Quote

The T-64 is a Soviet second-generation main battle tank introduced in the early 1960s. It was a more advanced counterpart to the T-62: the T-64 served in tank divisions, while the T-62 supported infantry in motorized rifle divisions. It introduced a number of advanced features including composite armor, a compact engine and transmission, and a smoothbore 125-mm gun equipped with an autoloader to allow the crew to be reduced to three so the tank could be smaller and lighter. In spite of being armed and armored like a heavy tank, the T-64 weighed only 38 tonnes (42 short tons; 37 long tons).

These features made the T-64 expensive to build, significantly more so than previous generations of Soviet tanks. This was especially true of the power pack, which was time-consuming to build and cost twice as much as more conventional designs. Several proposals were made to improve the T-64 with new engines, but chief designer Alexander Morozov's political power in Moscow kept the design in production in spite of any concerns about price. This led to the T-72 being designed as an emergency design, only to be produced in the case of a war, but its 40% lower price led to it entering production in spite of Morozov's objections.

At present the T-64 is in use in very few nations or regions, but is currently undergoing significant factory overhauls and modernization in Ukraine. The newest, vastly upgraded and improved model of this 50-year-old design, the T-64BM Bulat, has increased in weight to 45 tonnes and is seeing active service in the field.

https://en.wikipedia.org/wiki/T-64

The lessons from the past could also end up applying to current space industry.

Edited by Jacke
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3 hours ago, sh1pman said:

Has tourism for ultra-rich been ruled out?

To Mars?

Every single destination for humans in space needs to be constructed. There's no visiting Mars until someone builds something worth visiting on Mars. How much would you have to charge people to make that a worthwhile business model? Visiting Mars takes the "tourist" a min of what, 500-600 days (opposition). Not seeing much of a market. Hundreds of days in a tube for a month maybe on the surface, then back in the tube.

 

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The thumbnail isn't a great view, but I'm sure they've attached even more heat shield tiles. I think they must be aiming to complete the rectangle of tiles before flight.

Edited by RCgothic
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Cislunar tugs have been talked about for many decades. SpaceX might actually be able to do them, IMO. I know they have not talked about it, but it makes a lot of sense.

Imagine SS with the curved nose gone some number of rings above the dome. The fairing is attached using the same hardware used to to dock 2 SS together at the tail—resulting in a tug that can dock nose to tail with another SS.

This allows a 2-stage SS in orbit. I'm unsure about the ability of such a tug to aerobrake, but it seems like it should potentially be possible, otherwise it has to re-circularize in LEO after putting the other SS into an eccentric HEO (shy of TLI) propulsively—luckily for an empty vehicle this is surprisingly cheap in props.

Such a vehicle could give a full SS with 100t cargo 2300 m/s and leave props for 100% propulsive recircularization. Now we have a SS headed for the Moon fully tanked, and it needs to provide only 900m/s for TLI (305t props) itself. That gives us a lunar SS with 895t of props remaining otw to the Moon (I'm using 100t for the dry mass, so if SS is less, then more props or more cargo).

Assume its a normal SS that can aerobrake or aerocaptuure. If the cargo was propellants, and this was a ballistic trajectory to NRHO, we can in fact deliver 995t to NRHO. Some is needed for the 450 ms burn—less than 15t from NRHO. So we have a tanker at the Moon with980t of propellants. If LSS is 85t, then that's ~9.4km/s dv. ~5.5km/s is needed for the RT to the surface from there. Returning LSS has residuals, so future resupply can sacrifice propellant for cargo, and none the less slowly build up the props in LSS to being filled.

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8 hours ago, CatastrophicFailure said:

Gateway starts to look reeeeealy silly tho, stuck there as a little dot amongst assorted docked Starships, each several times its mass... :confused:

At that point use another bespoke SS as gateway.

BTW, the tug can have a crew compartment.

The top dome is sleeved with a single ring. There are then 4 ~1.8m rings before the nose cone—7.2m. My suggestion would be a 2 ring tall crew compartment (3.6m), giving a habitable volume of 229m3 (~3X Shuttle crew volume). That leaves the "trunk" at the nose. That section mimics the engine skirt area, including all SS docking hardware (including prop transfer?). In the center is an IDA, so crew or cargo vehicles can also dock to it along the center line. Tucked along the sides? Possibly a robot arm—we're building a tug here:

NASA9902057-x640.jpg\

U4dX8oN.png

EDIT: KSP quick versionThe top has a landercan stuck inside wirth a docking port on top to give an idea—yes, that's 9m in diameter. Engines in the skirt at the bottom.

This is a lower mass vehicle than LSS or SS, and can comfortably take crew on the 3 day trip to the Moon. You can use a frozen LLO, and take the propellant hit as well. The use of the Lagrange point family of orbits is not always a bad idea. Not sure on Earth-Moon phasing for something like NRHO vs a frozen, polar LLO.

Such a transfer vehicle could refill LSS, and deliver crew to it—crew put in LEO by existing crew vehicles at vastly lower cost than SLS/Orion. Both CC capsules were designed for 7 crew, and given that the tug will be in an ideal orbit for TX/FL launch, CCVs can do a rapid rendezvous in a few hours, so 7 crew is not a problem. We'd nearly double the Artemis astronaut count per mission.

Edited by tater
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19 hours ago, tater said:

From a purely business POV, Starship dev started partially because of Mars, which is NOT a business POV (no plausible business case for Mars)

I think that nearly all human interplanetary mission (including the Moon and the asteroids here as well) isn't that economical if we're excluding surface extraction. If surface extraction are possible (or at least pursued), then this means a self-sustaining outpost where time is  the only extra resource needed to keep beyond what was initially sunk in really. I know that's only break-even - only in the best scenario that (given that we mostly won't be able to get all the resources like we do on Earth) - but given the large effort needed that's a business case of it's own if there's enough interest.

While F9 and FH, along with Dragon, was merely a "solving business case" situation and is a very good stepping stone, SS and SH, if it works beyond what HLS wants, is a business scope expansion endeavor. Benefits of it's gigantic nature in other operating areas (LEO-MEO-HEO, Moon) is only second to what they're pursuing.

I guess the next question after HLS and Artemis (with the support of SS and SH) is whether we're greenlighting surface extraction on the Moon or other bodies, and how we will achieve that. Without it we're just getting ISS but at further distances away.

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1 hour ago, tater said:

Cislunar tugs have been talked about for many decades. SpaceX might actually be able to do them, IMO. I know they have not talked about it, but it makes a lot of sense.

Imagine SS with the curved nose gone some number of rings above the dome. The fairing is attached using the same hardware used to to dock 2 SS together at the tail—resulting in a tug that can dock nose to tail with another SS.

This allows a 2-stage SS in orbit. I'm unsure about the ability of such a tug to aerobrake, but it seems like it should potentially be possible, otherwise it has to re-circularize in LEO after putting the other SS into an eccentric HEO (shy of TLI) propulsively—luckily for an empty vehicle this is surprisingly cheap in props.

Such a vehicle could give a full SS with 100t cargo 2300 m/s and leave props for 100% propulsive recircularization. Now we have a SS headed for the Moon fully tanked, and it needs to provide only 900m/s for TLI (305t props) itself. That gives us a lunar SS with 895t of props remaining otw to the Moon (I'm using 100t for the dry mass, so if SS is less, then more props or more cargo).

Assume its a normal SS that can aerobrake or aerocaptuure. If the cargo was propellants, and this was a ballistic trajectory to NRHO, we can in fact deliver 995t to NRHO. Some is needed for the 450 ms burn—less than 15t from NRHO. So we have a tanker at the Moon with980t of propellants. If LSS is 85t, then that's ~9.4km/s dv. ~5.5km/s is needed for the RT to the surface from there. Returning LSS has residuals, so future resupply can sacrifice propellant for cargo, and none the less slowly build up the props in LSS to being filled.

Ooh! I really like this idea! And it gets even better with a 22m variant fairing Starship-tug filled to the cylindrical extent. ~2400m3 or ~2150t of propellant.

I'd probably keep some manner of fins and aerobrake back into LEO without landing. It could even go up with all RVacs as the intent is for it to never land.

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SS manufacturing is pretty inexpensive, and "space only" variants are lower in mass, and lower in complexity—all SS variants need solar, RCS, etc, but the atmospheric ones also need tiles, flaps, legs, etc).

It really does allow for some novel mission architectures.

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A 2-stage starship fully fuelled could weigh more than a Saturn V on the pad. Imagine a Saturn *starting* from LEO. Starship can do that. Tanker flights are inexpensive.

And then they could be daisy chained. Stick a third on the back. 3 stages can send a fully fuelled starship over a km/s past earth's escape velocity and still recover both tugs to LEO propulsively.

Four stages? That's a thousand tons to Trans Jupiter Injection.

 

If they can sort out trans-shipping of cargo, there's really no limit to the payload a starship can take along (as long as it doesn't all have to land).

 

Edited by RCgothic
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BTW, it looks like a "noseless" Starship acting as a tug could give a full SS ~2.3km/s and still put itself back in LEO.

Now we have a SS that has to do an additional ~2km/s for the Mars transfer orbit (total dv varies, lowest maybe ~3.5km/s). Our SS with the crew section and 10 tons of cargo (experiments and a rover?) masses 110t dry including that cargo. It has a dv of ~9.2km/s. We use 2 km/s to finish the MTO burn. SS now has 7.2 km/s. Landing and course corrections? A few hundred m/s? EDL is mostly aero, with propulsion at the end. Looks like ~6.8km/s is required for leaving the surface to an Earth transfer orbit. It's tight, but that seems to leave about 400 m/s to spare. Maybe stacked tankers as stages for more margin? The goal here is a Mars sortie... flags and footprints, plus proof of concept. Unlike direct it requires no ISRU, and could be done as an opposition class mission (much sorter mission duration)

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Next step back to classics, after the wings bended up, the aluminium instead of steel, and the heatshield tiles, will be the understanding of the fact that a cylinder is a bad, bad shape for reentry, and developing a BOR/Spiral/Dreamchaser shape, or so.

They have been experimenting with cylinders, cones, partially cut cones in 1960s.
Didn't work for them, won't work for them.

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20 minutes ago, JoeSchmuckatelli said:

Dumb jarhead asks 'why?' 

They have tried all simple shapes in the past and weren't happy with them.
Original hopes were that a simple cone can glide and fly like a plane at high speed, so finally they came to the specific shape.

They tried the cylinder even with race cars. With same result. 

Spoiler

images?q=tbn:ANd9GcTTCgDA55uPPYrVg3hcOCJimages?q=tbn:ANd9GcT8gfbqpid0fDlYpHM_Abo

 

bor-4-image04-s.jpg

Because air drag doesn't like such shapes, a lot of turbulences appear.
For a glider that's also low L/D which means high accelerations and narrow bottom with concentrated heating.
Flat bottoms have high L/D and dissipate the heat more effectively.

Bad, bad is the cylinder.

Edited by kerbiloid
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A cylinder is very good for designing propellant tanks. Which starship (and any ordinary rocket) is mostly, so it dictates the shape. As long as it survives reentry, its better this way at its main task.

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I am sure they have simulated whole reentry thoroughly. Empty Starship has relatively low mass/area -ratio, which probably gives more possibilities than compact capsule with high mass per area.

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Turbulence is irrelevant at hypersonic speeds. Basically punches a hole through the atmosphere with vacuum behind. If all you intend to do is aerobrake at high altitude and thrusters have enough control authority, it's no big deal.

It would be a problem for landing, but that's why all the variants that land have fins.

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