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SpaceX Dragon Returns Home From ISS (floridatoday.com)
An anonymous reader quotes a report from Florida Today: A SpaceX Dragon capsule that helped prepare the International Space Station for future commercial astronaut flights has returned to Earth after a stay of more than month-long mission. A robotic arm released the unmanned capsule packed with 3,000 pounds of cargo at 6:11 a.m. EDT, then fired thrusters several times to move a safe distance away from the station orbiting about 250 miles up. The departure began a less than six-hour journey that culminated in a Pacific Ocean splashdown at 11:47 a.m. EDT, about 300 miles southwest of Baja, California. The Dragon launched from Cape Canaveral early July 18 on a Falcon 9 rocket and berthed at the station two days later. Among the cargo brought back from space Friday were a dozen mice from a Japanese science experiment -- the first brought home alive in a Dragon. Samples from mice euthanized as part of an experiment by pharmaceutical company Eli Lilly also were on board. Results were returned from an experiment that studied the behavior of heart cells in microgravity, and from research into the composition of microbes in the human digestive system, NASA said. Findings from both could help keep astronauts healthy during deep space exploration missions. SpaceX plans to launch a Falcon 9 rocket from Cape Canaveral Air Force Station next Saturday, Sept. 3.
You know you didn't HAVE to read every article, right? Or do you just like to hear yourself bitch?
"Among the cargo brought back from space Friday were a dozen mice from a Japanese science experiment -- the first brought home alive in a Dragon. "
Okay... but what is the significance of this? The article itself doesn't really flesh this out either.
- Have they unsuccessfully tried to bring home live mice before, but they've always ended up dead?
- Have they successfully brought live mice back to earth, but in some other spacecraft?
- Are Dragon flights to the ISS frequent and routine to the point where we're left searching for a bunch of trivial "firsts" so we can write filler? E.g. First left-handed female crew member to ride a Dragon to/from the ISS...
#DeleteChrome
This is so much more important because instead of the usual military contractors building the capsule, an internet sensation military contractor is building the capsule, and it only took him 60 years to catch up.
You are welcome on my lawn.
So, how much did the shuttle cost per launch?
not quite the same - it's at a miniscule portion of what the costs were 60 years ago - not to speak of the increased reliability of the new hardware and launch ops.
Well, it beats making them into the world's most complicated airplanes as with the space shuttle. SpaceX has proven that they can do vertical landings of the first stage intact onto both land and a seagoing barge; after a trip out of the atmosphere and to about 1/5 of orbital velocity but not into orbit. They plan to do a parachute-less vertical landing of the Dragon capsule after a heat-shield re-entry. That turns out to be far less expensive and complicated than a space plane. It does turn out we need a lifting body for much larger vehicles. It still doesn't have to be a plane, though.
We don't need wings.
Bruce Perens.
It does turn out we need a lifting body for much larger vehicles.
Not if they're equipped with powerful-enough retros... ;)
Well, SpaceX just demonstrated supersonic retropropulsion over the past two years for vehicles that are 12 feet in diameter and start out at 1/5 orbital velocity. We have a lot of uncharted territory ahead.
Bruce Perens.
Not Slashdot's fault but still, where do they get these reporters?... "about 300 miles southwest of Baja, California".
SpaceX Dragon ...
I keep reading that as 'Spa sex dragon': Talk about click-bait.
We all know it. Most of that 3000lbs was waste disposal--IOW emptying their septic.
Hate to be the ground crew receiving it. LOL.
NASA announced it as Baja California without the comma. Mr. Dean doesn't usually get stuff wrong that way, he's a credible reporter on space missions. Maybe an editor or proofreader got it wrong. I sent him an email.
Bruce Perens.
Just a notice that Pinky and the Brain are back.
https://www.youtube.com/watch?...
errr....umm...*whooosh* *whoosh* Is this thing on ?
Just because you're a nobody doesn't mean nobody's life is affected by this.
Slashdot tagline: News for Nerds, Stuff that Matters
"and it only took him 60 years to catch up"
Given that he's only 45 and SpaceX is only 14, that's some kind of magic
Pain is merely failure leaving the body
Well, it beats making them into the world's most complicated air planes as with the space shuttle. SpaceX has proven that they can do vertical landings of the first stage intact onto both land and a seagoing barge; after a trip out of the atmosphere and to about 1/5 of orbital velocity but not into orbit.
It's great to see the myths of non-reusable first stage technology being dispelled.
That turns out to be far less expensive and complicated than a space plane. It does turn out we need a lifting body for much larger vehicles. It still doesn't have to be a plane, though.
I think you have to separate the concept from the implementation of a space plane design. SpaceX's launcher effort is less expensive and complicated than the space planes implemented so far. However both Buran and the Space Shuttle had the orbiter on the side of the stack where their heat shield was exposed to debris from the launch vehicle. So much so it was considered to be 'In-Family' because it would occur every launch to some degree.
The Space Shuttle also had all of the complexity related to the main engines which had no business being in orbit. Having the mass of those engines also complicates the infrastructure of landing. Considering also many of the political issues that interfered with the implementation of the Shuttle it wasn't the best design for a space plane.
We don't need wings.
They are useful though. The contrast is having the space plane at the top of the launcher stack, which removes the 'in-family' debris, main engine mass and, complexity issues for operating a space plane, as the X-37 demonstrates. The X-37 is covered by a shroud, however having some control surfaces at the top of a launch stack for a larger vehicle could be useful considering launchers have control surfaces near the base to balance it. A less massive orbiter means more for vehicle and payload reaching orbit and returning.
Musk has taken the pork barrelling out of launcher design and shown that it is possible to recover launcher assets. That knowledge maybe the foundation of opening up commercial space ventures paving the way for more commercial launcher platforms to become available.
The good thing about commercialization could mean someone implementing a space plane with a better design or more specific role. With those things in mind maybe we haven't seen the most optimal design for a space plane yet.
My ism, it's full of beliefs.
"A robotic arm released the unmanned capsule packed with 3,000 pounds of cargo at 6:11 a.m. EDT, then fired thrusters several times to move a safe distance away from the station orbiting about 250 miles up." Incredible! I thought they were attached to the space station.
It's great to see the myths of non-reusable first stage technology being dispelled.
Indeed, SpaceX has thoroughly demolished the claims of SSTO fans that reuse and low cost are somehow incompatible with staging. With an aluminum-bodied, pure-rocket launch system using simple kerosene-burning rocket engines, SpaceX has accomplished the bulk of what Skylon promises to one day achieve with its supertech air-breathing engines, liquid hydrogen fuel, eggshell-thin ceramic heat shielding, etc.
We don't need wings.
They are useful though.
For what? Air breathing launchers need them because of their weaker engines, but staged launchers don't need air breathing. For spacecraft, wings are just dead weight you wish was useful payload while operating in their primary environment, and highly stressed structures subject to catastrophic failure during atmospheric entry. Making spacecraft into poor imitations of aircraft for a brief portion of their flight will not make them as cheap to operate as aircraft.
Spaceplanes are dead. Take Skylon as a representative example: assuming it lived up to expectations, Skylon would have double the dry mass of the Falcon 9, about 10 times the unit cost, its complex engines and other systems would have operating costs that are higher by a similar factor, it'd have the additional headaches of operating with liquid hydrogen (largely unavoidable with spaceplanes), and all for somewhat lower payload than today's mostly-reusable Falcon 9, while competing with the fully reusable successor to the Falcon 9.
Even worse, Skylon would require an expendable upper stage for launches to geostationary orbit, which would likely make it less reusable than whatever SpaceX is operating by the time Skylon can fly. Not to mention that Blue Origin will likely have their orbital launcher up and running and the kinks of reuse worked out by that time as well...
Anyone who wants wings would have to prove that the vehicle weight would be lower with the wings than the engines and fuel for a precision vertical landing. There is no advantage to landing at a runway when you can land on what is effectively a helipad.
Bruce Perens.
I'd argue they need to prove that the vehicle weight is lower completely dry (and even that's biased in favor of airbreathing winged vehicles because it ignores the extra complexity and higher cost materials). It's the dry structure that's the expensive part to build and operate, you need the reduction in LOX tank size to make the vehicle smaller and cheaper after adding the wings, air breathing engines, landing gear, etc. If you can make the vehicle cheaper at the cost of pouring in a bit more propellant before launch, it's a win.
As it turns out, LOX is pretty compact and reducing the LOX tank size by airbreathing (again, the only real reason to carry wings) doesn't save much. The trade makes Skylon twice as heavy as the Falcon 9 despite using a super-advanced (and far more expensive per kg) carbon fiber frame instead of the Falcon 9's aluminum.
We could also use risk management metrics to make the case against spaceplanes. The shuttle had too many criticality 1 components, etc.
Bruce Perens.
It's great to see the myths of non-reusable first stage technology being dispelled.
Indeed, SpaceX has thoroughly demolished the claims of SSTO fans that reuse and low cost are somehow incompatible with staging.
We agree that this is a step forwards in getting to orbit.
We don't need wings.
They are useful though.
For what?
For operating a vehicle in atmosphere, which occurs at two critical stages of a spacecraft's mission.
Spaceplanes are dead.
Does a spaceplane have to include engines?
Take Skylon as a representative example:
No. That is specifically the design I am arguing against. Please check my post again and you will see I deliberately *exclude* the mass of the engines.
Perhaps it would make more sense if I introduced the term "Space Glider" to describe what I am talking about.
assuming it lived up to expectations, Skylon
I agree, I doubt this design would have lived up to expectations and what we have seen is failed designs for a sort of spaceplane with engines. What my OP was suggesting was that we have not seen the most optimized design for a space plane, or more specifically, a space glider.
My ism, it's full of beliefs.
Falcon 9 isn't Al. It's Al-Li with a composite interstage. It also has a lower dry mass than iso-grid designs like the EELVs.
Al-Li is ~95% Al. Nobody lists all the components of an alloy every time they refer to the primary material. And the interstage is a tiny fraction of the structure, which originally only served to connect the stages and house separation hardware. It's not at all comparable to Skylon's composite LH2 tanks and airframe.
They've done a good job of optimizing it, but that doesn't change the fact that they chose stir-welded aluminum because it was relatively cheap and easy compared to higher performing alternatives such as carbon fiber. Recent rumors hint that their future projects will make heavy use of carbon fiber, but for staged vehicles it's an optimization for improving performance and SpaceX was able to avoid it for most things until they got established and worked out reuse, while it's virtually a requirement for SSTO craft and spaceplanes just to reach orbit.
For what?
For operating a vehicle in atmosphere, which occurs at two critical stages of a spacecraft's mission.
That doesn't answer the question. Spacecraft spend only a tiny fraction of their lives in the atmosphere, and sustained aerodynamic flight is not a requirement during their short passages through it during launch and landing. So what do they need wings for?
No. That is specifically the design I am arguing against. Please check my post again and you will see I deliberately *exclude* the mass of the engines.
Engines using diluted low-pressure gaseous ambient oxygen as an oxidizer have poor thrust to weight ratios, and wings are generally used to make up for that, making it possible for a craft with underpowered engines to accelerate early on, though at a cost in aerodynamic drag and sustained heating. If you're *not* using air-breathing engines, you can just fly a near-vertical trajectory that quickly exits the bulk of the atmosphere, without having to deal with aerodynamic drag and heating. As for the return, where are you trying to go between reentry and landing? What do you need wings for?
(Note: "to operate from an airport" is not an answer. Needing a reinforced extra-long runway in addition to all the usual pad infrastructure is a cost, not a benefit.)
That said, the point of a SSTO with airbreathing is not the *cost* of the fuel, but the weight-reduction itself, since the added weight that has been avoided in this way can be used for payload.
Even Elon Musk said it's not about the cost of the fuel, but the fact it impacts the useful weight of the payload. ;-)
It's possible, thus, that for LEO an airbreathing spaceplane is more suited than a rocket, especially if that rocket isn't fully SSTO. You say it doesn't save 'much', but the oxidiser on a typical rocket makes out about a third of the total mass... I would call that pretty much.
--- "To pee or not to pee, that is the question." ---
Did you miss the part about Skylon having double the dry mass of the Falcon 9?
Is Skylon the only possible system using atmospheric air?
People seem to be a bit too much focussed on Skylon, although I admit I'm interested in it too, from a technical/technological standpoint.
The *principle* of the matter I just explained stands, though: that which you avoid taking with you as weight (the oxidiser) means you do not have to carry that weight, plus, you don't need to carry the weight of the fuel needed to carry the weight of the oxidiser, plus you do not need the weight of the fuel to lift the weight of the fuel that is needed to lift of the oxidiser, etc. There is a considerable reduction in weight, thus, and - as said - that matters for the useful payload, not for the reduction of *cost of the fuel* as some posts imply.
Whether or not the reduction of weight is always offset by the additional complexity and added weight (of the wings and engines, for instance), remains to be seen, but I would wager that totally depends on what system you use. Especially with non-SSTO systems (the Falcon is non SSTO too, after all) there are myriads of options one could use, and I doubt they'll all be 'worse' than the current Falcon-oxidiser-carying-system in regard of dry mass.
That said, if you're talking economically, and especially if you're talking specifically of Skylon, I think the reusable Falcon is far more viable. But just like all his competitors thought re-usability of a rocket was not (cost/benefit) worthwhile, and Elon Musk is (going to) proving them wrong, it might be that someone smart comes along, also with new ideas how to tackle things, and get affordable air-using systems going, which would be a new 'disruptive technology'. After all, the advantages - at least in principle - I explained in my former post remain valid and are physical sound. It's just a matter of finding a good approach that outpaces current systems.
--- "To pee or not to pee, that is the question." ---
Well if you remember the X-33 debacle, or the Boeing 787 debacle, composites aren't always the best idea. It's a lot easier to repair Al-Li than composites which is important for a reusable vehicle. Also AFAIK you need a large oven to cure the composites or an autoclave. I wouldn't be surprised if it took a lot longer to manufacture a composite structure which has an impact on production capacity and cost per unit. Al-Li might seem trivial now but a couple of decades back when NASA was doing the DC-XA they had to source a Al-Li propellant tank from Russia. Fact is Al-Li did not enter common usage in aerospace that long ago.
Composites are not a requirement for an SSTO. You need lightweight structures but composites are not necessarily the best way to do it. I have seen all sorts of proposals on how to get to the required weight fractions but without actual hardware flying its hard to be sure what's better. I am not even sure an SSTO is that necessary to begin with as long as the second stage is simple and cheap enough to be discarded.
Skylon has too many unknown factors in it. I think the engine itself has interesting ideas but that it's a bad match for an SSTO. The LAPCAT proposal they made for an HST with the SCIMITAR engine makes more sense.
What do you need wings for?
As I said. What my OP was suggesting was that we have not seen the most optimized design for a space plane, or more specifically, a space glider. We have never implemented a low mass glider from space.
Note: "to operate from an airport" is not an answer.
To reduce ballistic forces on re-entry, to not carry volatiles for landing, to carry more than three tons of payload back to earth, to build a simpler vehicle. Perhaps to use some of the launch energy on delivering a product produced in orbit to a specific place on earth. I don't know what possible future requirements there are. Any improvement to ablative heat shield technology, as the Dragon V2 will produce, can also be applied to a space glider.
You might be right or wrong. I'm not religiously connected to the idea of having wings in space enough to care. I accept all of the reasons you point out as pretty good reasons for not having winged space vehicles, however it still doesn't change what I saying: we have not seen the most optimized design for a space vehicle of this kind, specifically a space glider. That has nothing to do with the obsolescence of a design, idea or concept, simply a statement of fact.
My other suggestion was if there is a reason to have a space glider then the emerging market economy for space products will produce one.
Thanks for the conversation, I'll be in surgery and out of action for a while.
My ism, it's full of beliefs.
We could also use risk management metrics to make the case against spaceplanes. The shuttle had too many criticality 1 components, etc.
The Shuttle had those critical components because it was a complex vehicle with launch components on it. If you are using the risk management metrics of a side by side launch configuration with engines in it, then we are not talking about the same thing.
The CAIB report pointed out that it's risk analysis of the shuttle launch configuration produced approximately 130 impacts to the heat shield per launch. That would be eliminated in a top of stack configuration. So too would the main engines making for a less complex, less massive vehicle. A space glider.
Whether you need wings is not what I am saying, I am making the observation that none of the designs we have seen implemented produced an optimal vehicle.
Perhaps Boeing knows something we don't.
My ism, it's full of beliefs.
There's no denying that the x-37b is impressive. Sierra Nevada might have a good idea, but I'm dubious about the progress and readiness of Dream Chaser. Boeing? I don't understand your point about Boeing.
Bruce Perens.
Boeing? I don't understand your point about Boeing.
That they would have considerable experience to bring to optimizing such a space glider (x-37b) and that they selected that design to demonstrate the technology.
My ism, it's full of beliefs.
Yes, but their candidate for Commercial Crew is the CST-100. Which looks like a modernization and upscaling of the Apollo CM. And they left it to Sierra Nevada to propose a space plane.
Bruce Perens.
And they left it to Sierra Nevada to propose a space plane.
Indeed and you have supplied good examples of the craft with Dream Chaser, which is a more optimized design - thanks. I accept your's and cjameshuff's points about a space plane. I'm not arguing a capsule vs plane approach, simply commenting on the state of art in that technology. If a market emerges perhaps we will see more of them.
Yes, but their candidate for Commercial Crew is the CST-100. Which looks like a modernization and upscaling of the Apollo CM.
I have nothing against the capsule approach and have often lamented on how progressed space travel might have been had the Apollo platform been developed more. Far from arguing against the development of this type of vehicle, I'm excited that we are able to have a conversation like this and that there are three 7 crew member options available all vying for a role taking people to space.
The commercialization of space is one of the most exciting things I have seen for a while, I'm grateful for Elon Musk's efforts.
I won't be able to respond to further posts for a while as I am of to get some surgery on my spine today. Thanks for the conversation.
My ism, it's full of beliefs.
SpaceX has thoroughly demolished the claims of SSTO fans that reuse and low cost are somehow incompatible with staging. With an aluminum-bodied, pure-rocket launch system using simple kerosene-burning rocket engines, SpaceX has accomplished the bulk of what Skylon promises to one day achieve with its supertech air-breathing engines, liquid hydrogen fuel, eggshell-thin ceramic heat shielding, etc.
Let NASA manage this and I bet they can prove the opposite after a few test flights.