Not better for easy reusabillity or making fuel on Mars though.That's the neat thing with LOX, the O/F ratios in the 3 range. 1 hydrocarbon needs 3 LOX to burn. In the end the amount of fuel is small when the amount of oxidizer (LOX) is huge.
Of course kerosene / peroxide is even better: O/F ratio of 7 !
Surely you understand the difference between a publicly funded program (SLS) and a private company selling goods/services?Didn’t say it was a donation, and doesn’t change my point.
Of course it does. There isn't a company on the planet that doesn't depend on customers.
My point was that you appeared to be suggesting that Space X had got where it was now on just private money.
With respect, this is a little inaccurate. He said that the individual barrel-ring sections would be produced directly "off the spool" with each joined via a single continuous weld, not that the entire hull would be produced from one piece of steel.As an example of that optimisation though, quite soon they plan on producing Starship hulls via a continuous reel of steel (which is normally cut into plates at their supplier's factory) and use a single continuous weld, giving them more strength and therefore allowing thinner steel to be used.
That's the neat thing with LOX, the O/F ratios in the 3 range. 1 hydrocarbon needs 3 LOX to burn. In the end the amount of fuel is small when the amount of oxidizer (LOX) is huge.
Of course kerosene / peroxide is even better: O/F ratio of 7 !
With respect, this is a little inaccurate. He said that the individual barrel-ring sections would be produced directly "off the spool" with each joined via a single continuous weld, not that the entire hull would be produced from one piece of steel.As an example of that optimisation though, quite soon they plan on producing Starship hulls via a continuous reel of steel (which is normally cut into plates at their supplier's factory) and use a single continuous weld, giving them more strength and therefore allowing thinner steel to be used.
As an austenitic stainless steel, Core 301/4310 has good weldability and is suitable for the full range of conventional welding methods (like MMA, MIG, MAG, TIG, SAW, LBW, or RSW), except gas welding. Core 301/4310 has about 50% higher thermal expansion and lower heat conductivity compared to carbon steels. This means that larger deformation and higher shrinkage stresses may result from welding.
Surely you understand the difference between a publicly funded program (SLS) and a private company selling goods/services?Didn’t say it was a donation, and doesn’t change my point.
Of course it does. There isn't a company on the planet that doesn't depend on customers.
My point was that you appeared to be suggesting that Space X had got where it was now on just private money.
Can't help you. If you didn't understand it the first time, repeating myself won't help you.Surely you understand the difference between a publicly funded program (SLS) and a private company selling goods/services?Didn’t say it was a donation, and doesn’t change my point.
Of course it does. There isn't a company on the planet that doesn't depend on customers.
My point was that you appeared to be suggesting that Space X had got where it was now on just private money.
Yes. But then I regard your original post as unclear.
Gentlemen,Can't help you. If you didn't understand it the first time, repeating myself won't help you.Surely you understand the difference between a publicly funded program (SLS) and a private company selling goods/services?Didn’t say it was a donation, and doesn’t change my point.
Of course it does. There isn't a company on the planet that doesn't depend on customers.
My point was that you appeared to be suggesting that Space X had got where it was now on just private money.
Yes. But then I regard your original post as unclear.
As I noted before Elon has an agenda that pretty much requires this approach but that in no way makes it the BEST or even the smartest way to do things. If it works as planned and blows open space I will have no heartburn or complaints. If it doesn't there's going to be another 'space-crash' and I've been through enough of those already to want to see another one.
Spot on. Musk is trying to marry "Saturn V HLV" with "full-reusability" and the end result - a brute force approach - is so huge, so massive, it can only be justified by a grand scale onslaught on Mars. Although it could be very interesting for the Moon, too, admittedly.
But that's only the human exploration part of space.
Commercial space might think it is a little oversized.
I mean, the 747 is an outstanding aircraft, but for Ryanair or Easyjet low-cost short-haul airlines it would be completely overkill. Which mean: there is room for smaller RLVs just like there is is room for much smaller airliners bar 747 or A380 (fortunately enough).
Musk somewhat acknowledged this recently when he admitted that Falcon 9 and Heavy might not be replaced by Starship-Super-heavy.
Also for space tourism / passenger transportation (suborbital, orbital, cislunar, whatever) Starship is really huge. Finding enough people to fill all these seats won't be an easy task.
Whatever, if that works, Musk will have accomplished full-reusability the Bono / Truax way (king size) rather that "The Rocket Company DHC-1" style. Starting with an enormous vehicle with a huge payload.
One thing Scott Manley pointed out in his review of the presentation is that it's not likely that Starship will be used to service the Moon for very long if it is used to land there. The math shows the raptors are going to throw some regolith pretty far, (possiblity of some of the debris almost making orbital velocity) with all that implies for 'sandblasting' any nearby structures
Re: a SpaceX lander. I'm think it would be relatively easy for them to adapt some of their existing hardware. Question is, how big can you realistically go without causing too much erosion at landing? And maybe they only need a temporary solution for that anyway. Once a hardened landing pad is operational that problem goes away.
Re: a SpaceX lander. I'm think it would be relatively easy for them to adapt some of their existing hardware. Question is, how big can you realistically go without causing too much erosion at landing? And maybe they only need a temporary solution for that anyway. Once a hardened landing pad is operational that problem goes away.
There is also ULA bold and clever "horizontal lander" concept. Make the descent from LLO to 2 miles over the lunar surface, on the huge engine; then flips to horizontal and land smoothly on banks of smaller thrusters.
RanulfC said:The question though is do we really NEED a Saturn V class rocket and payload capability or do we need regular and inexpensive access to orbit. The two while not mutually exclusive are also not automatically the same for a reason.
I think this is absolutely a point worth making. I also think it might be a tad short-sighted.
I am not Musk's biggest booster (bad pun had to be made), but if he delivers, you might see a paradigm shift of sorts: to this point, satellite design has been heavily dictated by weight because of the exorbitant costs. If you can bring costs down substantially, it might not matter that a future refined Falcon grants a lower $/lb rate: there may be a shift at some price point toward heavier satellites which trade weight gain for capability/longevity/survivability. And that might make heavy or super-heavy lift essential.
Actually satellite mass has apperently been going down for the last few decades rather than continuing to grow as was originally assumed would happen. Higher reliability parts, the ability to reconfigure the system on the 'fly' to bypass malfunctions and damage and other inovations have made modern satellites more capable at the same or lesser mass than pervious satellites.
There are a lot of things one might want in a spacecraft/satellite that are simply abandoned right now because of weight and the extremely high $/lb rates. Commercial space programs exist, so clearly the market can bear the current costs. If prices come down substantially, maybe adding more fuel for longer missions, physical shielding against collisions with space debris, perhaps shaping and even thick RAM for certain customers becomes much more attractive. You may start to see design compromises take advantage of the lower $/lb to achieve greater capability and cost to the extent we can drive down price -- and that will require higher payload to orbit capabilities than designs that are strictly weight-driven.
Does it really matter that I can get a microsat to orbit with a Pegasus launch for substantially lower-$/lb if Pegasus doesn't loft enough payload to carry the design/capabilities that I'm willing to pay for?
Re: a SpaceX lander. I'm think it would be relatively easy for them to adapt some of their existing hardware. Question is, how big can you realistically go without causing too much erosion at landing? And maybe they only need a temporary solution for that anyway. Once a hardened landing pad is operational that problem goes away.
One thing Scott Manley pointed out in his review of the presentation is that it's not likely that Starship will be used to service the Moon for very long if it is used to land there. The math shows the raptors are going to throw some regolith pretty far, (possiblity of some of the debris almost making orbital velocity) with all that implies for 'sandblasting' any nearby structures
Wow. Never, ever thought about this. You said orbital lunar velocity ? as in, what, 2.5 km/s ? no need for mass driver then
Which makes me wonder, might still be a problem on Mars. Stronger gravity plus atmosphere, ok, but still...
As for a lunar base, the more I learn about Oceanus Procellarum / Marius Hills, the more I like it. It has large underground lava tubes with a big skylight / opening; some interesting KREEP ore concentrations; and also some of Kagyua underground reflectors that might be underground water (if not false signal, admittedly).
Smooth the interior of the cave, crush the rocks removed into LUNOX, then inflate BA-330s or BA-2100s Bigelow modules. Chain them like sausages. Rinse, repeat. Could make one hell of a lunar base, even more since calculation shows that lunar weak gravity would allow 3-miles wide caves.
And being underground, it would not care about Starship sending regolith flying all over the place.
There is also ULA bold and clever "horizontal lander" concept. Make the descent from LLO to 2 miles over the lunar surface, on the huge engine; then flips to horizontal and land smoothly on banks of smaller thrusters.
Musk’s Amped-Up Timetable for Mars Spaceship Contrasts With Delays for NASA Capsules
Elon Musk has stoked excitement about accelerated development of private deep-space vehicles by projecting his proposed megarocket targeting Mars could take humans on an orbital test flight around Earth as soon as next year.www.wsj.com
Do you have a link to an article, etc where he says Falcon 9 / Heavy might not be replaced by Starship? If he did say that, I imagine that would just be in the event that Starship turns out to be significantly more expensive to operate than expected.I mean, the 747 is an outstanding aircraft, but for Ryanair or Easyjet low-cost short-haul airlines it would be completely overkill. Which mean: there is room for smaller RLVs just like there is is room for much smaller airliners bar 747 or A380 (fortunately enough).
Musk somewhat acknowledged this recently when he admitted that Falcon 9 and Heavy might not be replaced by Starship-Super-heavy.
The article might have been in error and been edited since your post, but they expect to begin flight tests in one to two months rather than weeks.Elon Musk is upbeat about Starship 1 flight tests, he said that they would begin in one to two week’s.
https://www.bbc.co.uk/news/science-environment-49870154
Perhaps they could do something with those methalox RCS thrusters that they want to replace the Starship's cold gas thrusters with on Mk5+. They're already going to be doing a suicide burn with Raptor to land on the Moon (3x Raptors for symmetry at minimum throttle still have a T:W of 1.05 with Starship 100% fueled and with 150t of payload), so maybe they could kill their speed with the Raptors, then cut them and descend under the power of something kind of arrangement of methalox UltraDraco engines; perhaps mounted along the raceway between the fins, angled diagonally downward or something.Well the main thing is as long as your engines are on the bottom of your lander they are going to throw up debris. (Less with a hardened pad but there will still be some, and they you have to worry about exhaust reflection onto the bottom of the vehicle) One way to mitigate this of course is to move your landing engines upwards such as in the Hercules lander, (https://www.secretprojects.co.uk/threads/nasa-hercules-landing-vehicle.32337/#post-362255) and some other VTVL lander concepts. You lose some efficiency of course but it may be worth it since you can also put your cargo/passenger bay lower down and therefore have easier off/on-loading of both.
Re: a SpaceX lander. I'm think it would be relatively easy for them to adapt some of their existing hardware. Question is, how big can you realistically go without causing too much erosion at landing?
Do you have a link to an article, etc where he says Falcon 9 / Heavy might not be replaced by Starship? If he did say that, I imagine that would just be in the event that Starship turns out to be significantly more expensive to operate than expected.
As it is today, Falcon 9 is like a 737 (vs Starship being an A380), but a 737 that has to jettison an entire engine nacelle before landing. They were and might still be looking at cost effective methods of returning F9 second stages, but unless that happens there is a decent chance that Starship could turn out to be cheaper to launch (with a number of reuses of course) than Falcon 9, let alone Falcon Heavy.
Perhaps they could do something with those methalox RCS thrusters that they want to replace the Starship's cold gas thrusters with on Mk5+. They're already going to be doing a suicide burn with Raptor to land on the Moon (3x Raptors for symmetry at minimum throttle still have a T:W of 1.05 with Starship 100% fueled and with 150t of payload), so maybe they could kill their speed with the Raptors, then cut them and descend under the power of something kind of arrangement of methalox UltraDraco engines; perhaps mounted along the raceway between the fins, angled diagonally downward or something.
Obvious solution: landing "tractor" engines at the nose. These would necessary have some losses since you'd have to angle them off to the side to keep from tearing up the sides of the vehicle, but it shouldn't be too bad.
And if the weight hit of added engines in the nose is problematic, you could mount the engines to a ring... and leave them in lunar orbit. Starship comes from Earth, enters lunar orbit, docks with the engines, lands, lifts off, leaves engines in lunar orbit.
At which point you'd need to ask if you really want to try and use Starship for everything? It might be just better to add a cargo section to the 'ring' and ferry the payload down to the surface and back rather than bring Starship down and up again.
I'd say have the ring include *just* the engines and attachments, never mind propellant and tankage. That would remain in the Starship. The engines would be to Starship what a tug is to a ship... or a jetliner.
Sure, which requires new feed lines and attachment point on Starship to support using a single system it uses only during one route,
Which still avoids the actual question which is does taking Starship down to the Lunar surface and back to orbit make enough sense to justify not using a seperate more effiecent vehicle to do it with?
Maybe early on and for a short time ...
And if the weight hit of added engines in the nose is problematic, you could mount the engines to a ring... and leave them in lunar orbit. Starship comes from Earth, enters lunar orbit, docks with the engines, lands, lifts off, leaves engines in lunar orbit.
Just imagine the same interview with the head of ULA. It could only be far less inspiring and cool; A non happening.