The parent wrote "returnshuttles", which I interpreted as meaning that they wanted to use Falcon-based hardware to return payload (humans, samples, whatever) from the moon.
Huh? Were you thinking of stowing away in the Falcon's first stage?
There are no plans by SpaceX to ever have people land in that manner. Dragon (the part humans actually ride in) has both parachutes both retrorockets, only one of which needs to work, and a degree of "crumple zone" (shock-absorbing legs plus the heat shield and service hardware) in case of partial failures of either of the two.
Perhaps you also missed the fifty or so times that the SpaceX newscasters added the word "experimental" before the word "landing". Would you prefer that like most companies they keep their development work in secret? Or should every company be like them, with, say, car manufacturers releasing footage every time, say, a new experimental safety-critical system ends up with a test car plowing into a fence?
The Shuttle SRBs were parachute landings. They landed at nearly highway speeds. It's hard to parachute land a gigantic, fragile object and have it be intact. And seriously, parachutes are way more likely to go offtrack than engine-guided landings.
SpaceX is nice enough to not hide their engineering development program from us, but you'll note that they keep driving the point home that these are experimental landings. Neither their core business, nor their customers, require them to work. They have dozens of boosters to try with every year, and they're unmanned - they don't have to get it right every time.
Unfortunately, the only way to truly try out rocket landing.... is to try out rocket landing. It's not like a computer programmer who can just run the program in his test environment numerous times before release, or a car manufacturer who can keep trying out their car systems on private test tracks until the bugs are ironed out. It's not even incremental improvements over earlier rockets in a family that already had most of its bugs worked out in the past. If SpaceX wants to get rocket landing right... they need to land rockets, and learn from that.
The whole point of what SpaceX is doing is to make the economics like those of airplanes. They want airplane-like economics. Arianespace is seeking economics that would never work out with airplanes.
And yes, the engines and electronic systems on an airplane are way more expensive than the fuselage.
Generally, having land downrange is considered a bug, not a feature. It makes permitting very hard because nobody likes the concept of half a million kilograms of explosive fuel and oxidizer along with tons of shrapnel-aluminum skin and big heavy engines landing in their town in the event of failure where the self-destruct mechanism doesn't do its job.
That said, yes, Florida is probably enough downrange so as not to be a major source of concern. Still, I'd think it would be too far for Falcon 9 boosters, at least on most missions. Maybe it would be suitable for Falcon Heavy's core stage, though.
The rocket launches upright. It's designed to bear loads vertically being imparted through its base. It's not designed to dangle from a cable from its nose. Plus, in terms of "things that can go wrong", grappling onto elevated cables sounds far worse than landing on legs.
From the look of it, the real culprit this time was ice, from all of the fog. That's the leading theory as to why the leg didn't latch. Unfortunately, icing on aerial vehicles in general has killed an awful lot of them over the course of modern history.
Unfortunately, LOX/RP-1 like SpaceX uses now isn't a great fuel for lunar operations. For a small lunar craft, you want something that has very small, light and simple engines, like a monoprop or hypergolic biprop; if your landing craft is bigger, you want something very high ISP. In both cases it's about keeping your mass down because you're so far down the chain on the rocket equation that any small change in mass (esp on the return stage) has a huge impact on the launch mass. Things that LOX/RP-1 excels at, such as thrust, aren't very important in lunar operations. And it would be extremely hard to make RP-1 there because of the shortage of carbon (even hydrogen is unavailable in most locations, but there are some isolated places where it appears to be present in good quantities).
In terms of lunar-manufactured propellants, obviously LOX/LH has gotten a lot of attention. But another interesting one is ALICE - aluminum-ice. Aluminum is an extremely energetic metal - we don't see this side of it often because its surface coating of aluminum oxide is so effective at shielding it. But aluminum can burn not only in oxygen but also carbon dioxide and water (which is why when you weld aluminum you can't use CO2 as a shielding gas). There's only a few other elements out there whose oxides aluminum won't gladly strip the oxygens from at high temperatures - which is why thermite works, and why it can explode fiercely in contact with water. Its affinity for oxygen is so much greater than water's that the two actually make a pretty strong propellant combination - the key is getting past that oxide layer (which has been achieved pretty well in lab scale propellant mixes). The main advantage of ALICE over LOX/LH in lunar operations is not having to deal with leaky, frigid, low density hydrogen.
Unfortunately, while aluminum oxides are incredibly abundant on the moon, ALICE doesn't work where you don't have water ice. You can't just burn a stoichometric ratio of aluminum and oxygen because the hydrogen is actually very important - burned aluminum (aluminum oxide) condenses out at very high temperatures. No gas = no expansion = no thrust**. You need another gas - the lighter the better, and nothing beats hot hydrogen - to take the heat from the aluminum oxide (not just the heat of combustion, but also the heat of condensation). So this rules out most of the moon, only water-rich areas (albeit, those are the places you'd want to set up a colony). Elsewhere, you could use excess oxygen as your heat transfer gas, but at 16 AMU, it's no lightweight. Another possibility would be to outgas helium from regolith, but you'd have to go through a lot of regolith for that much helium.
On Mars it's much easier, as both carbon and hydrogen are abundant. SpaceX rightfully realized that for Mars you either need a very high ISP or a local propellant supply in order to have reasonable launch masses, and have opted for the latter with the Raptor LOX/Methane engine that they're working on. But that's just one of numerous possibilities on the red planet. A more unusual possibility involves the use of the abundant soil perchlorates as an oxidizer with any number of potential fuel species - they're easier to store than LOX and lower energy to produce (albeit lower performance).
** Likewise, when aluminum is added to a hydrocarbon mixture, the optimum ratio of oxygen, hydrocarbon and aluminum is one where the carbon only burns to CO, not CO2 - you want your carbon exhausts in a gaseous form, but your main goal as far as energy release goes is to burn the aluminum; the extra energy you get from carrying additional oxygen to fully burn the carbon is more efficiently spent carrying more stoichiometric mix of aluminum and oxygen for them to burn together.
To be fair to the submitter, I think they just misinterpreted the news as meaning that the rocket didn't tip over and merely damaged a leg. That misinterpretation may be due to overoptimism on their part, but I'm not going to psychoanalyze them.
Regardless, we now know that this incident was due to "Touchdown speed was ok, but a leg lockout didn't latch, so it tipped over after landing." The question is why the leg didn't latch.
However, that was not what prevented it being good. Touchdown speed was ok, but a leg lockout didn't latch, so it tipped over after landing.
Great to have the update. Not so great for whatever people were in charge with making, prepping, and inspecting the legs;) Unless it was a design flaw.
I guess we have a new question now - why it didn't lock.
Even if we assume a perfectly stable platform, the fact that the drone ships are so much smaller than the ground landing pad means that the rocket has to do much more precise corrections to ensure that they land on it.
Slashdot Mirror
The parent wrote "returnshuttles", which I interpreted as meaning that they wanted to use Falcon-based hardware to return payload (humans, samples, whatever) from the moon.
Huh? Were you thinking of stowing away in the Falcon's first stage?
There are no plans by SpaceX to ever have people land in that manner. Dragon (the part humans actually ride in) has both parachutes both retrorockets, only one of which needs to work, and a degree of "crumple zone" (shock-absorbing legs plus the heat shield and service hardware) in case of partial failures of either of the two.
Perhaps you also missed the fifty or so times that the SpaceX newscasters added the word "experimental" before the word "landing". Would you prefer that like most companies they keep their development work in secret? Or should every company be like them, with, say, car manufacturers releasing footage every time, say, a new experimental safety-critical system ends up with a test car plowing into a fence?
You mean the stuff that regularly takes down airplanes, despite over a century of experience?
Indeed. Don't like the result of this launch? Just wait a couple weeks. ;)
Seriously, that was a beautiful landing. If that leg had latched that rocket would be being offloaded right now.
The Shuttle SRBs were parachute landings. They landed at nearly highway speeds. It's hard to parachute land a gigantic, fragile object and have it be intact. And seriously, parachutes are way more likely to go offtrack than engine-guided landings.
SpaceX is nice enough to not hide their engineering development program from us, but you'll note that they keep driving the point home that these are experimental landings. Neither their core business, nor their customers, require them to work. They have dozens of boosters to try with every year, and they're unmanned - they don't have to get it right every time.
Unfortunately, the only way to truly try out rocket landing.... is to try out rocket landing. It's not like a computer programmer who can just run the program in his test environment numerous times before release, or a car manufacturer who can keep trying out their car systems on private test tracks until the bugs are ironed out. It's not even incremental improvements over earlier rockets in a family that already had most of its bugs worked out in the past. If SpaceX wants to get rocket landing right... they need to land rockets, and learn from that.
The whole point of what SpaceX is doing is to make the economics like those of airplanes. They want airplane-like economics. Arianespace is seeking economics that would never work out with airplanes.
And yes, the engines and electronic systems on an airplane are way more expensive than the fuselage.
Please learn the meaning of the word "yet". There was no video of the event at the time, nor anyone on the barge who could have seen it.
You can learn new words in the teacher's lounge.
Generally, having land downrange is considered a bug, not a feature. It makes permitting very hard because nobody likes the concept of half a million kilograms of explosive fuel and oxidizer along with tons of shrapnel-aluminum skin and big heavy engines landing in their town in the event of failure where the self-destruct mechanism doesn't do its job.
That said, yes, Florida is probably enough downrange so as not to be a major source of concern. Still, I'd think it would be too far for Falcon 9 boosters, at least on most missions. Maybe it would be suitable for Falcon Heavy's core stage, though.
The rocket launches upright. It's designed to bear loads vertically being imparted through its base. It's not designed to dangle from a cable from its nose. Plus, in terms of "things that can go wrong", grappling onto elevated cables sounds far worse than landing on legs.
From the look of it, the real culprit this time was ice, from all of the fog. That's the leading theory as to why the leg didn't latch. Unfortunately, icing on aerial vehicles in general has killed an awful lot of them over the course of modern history.
I have it on good word that there's whales there. Me and some of the boys from Nantucket are looking into what it'd cost to get up there.
Unfortunately, LOX/RP-1 like SpaceX uses now isn't a great fuel for lunar operations. For a small lunar craft, you want something that has very small, light and simple engines, like a monoprop or hypergolic biprop; if your landing craft is bigger, you want something very high ISP. In both cases it's about keeping your mass down because you're so far down the chain on the rocket equation that any small change in mass (esp on the return stage) has a huge impact on the launch mass. Things that LOX/RP-1 excels at, such as thrust, aren't very important in lunar operations. And it would be extremely hard to make RP-1 there because of the shortage of carbon (even hydrogen is unavailable in most locations, but there are some isolated places where it appears to be present in good quantities).
In terms of lunar-manufactured propellants, obviously LOX/LH has gotten a lot of attention. But another interesting one is ALICE - aluminum-ice. Aluminum is an extremely energetic metal - we don't see this side of it often because its surface coating of aluminum oxide is so effective at shielding it. But aluminum can burn not only in oxygen but also carbon dioxide and water (which is why when you weld aluminum you can't use CO2 as a shielding gas). There's only a few other elements out there whose oxides aluminum won't gladly strip the oxygens from at high temperatures - which is why thermite works, and why it can explode fiercely in contact with water. Its affinity for oxygen is so much greater than water's that the two actually make a pretty strong propellant combination - the key is getting past that oxide layer (which has been achieved pretty well in lab scale propellant mixes). The main advantage of ALICE over LOX/LH in lunar operations is not having to deal with leaky, frigid, low density hydrogen.
Unfortunately, while aluminum oxides are incredibly abundant on the moon, ALICE doesn't work where you don't have water ice. You can't just burn a stoichometric ratio of aluminum and oxygen because the hydrogen is actually very important - burned aluminum (aluminum oxide) condenses out at very high temperatures. No gas = no expansion = no thrust**. You need another gas - the lighter the better, and nothing beats hot hydrogen - to take the heat from the aluminum oxide (not just the heat of combustion, but also the heat of condensation). So this rules out most of the moon, only water-rich areas (albeit, those are the places you'd want to set up a colony). Elsewhere, you could use excess oxygen as your heat transfer gas, but at 16 AMU, it's no lightweight. Another possibility would be to outgas helium from regolith, but you'd have to go through a lot of regolith for that much helium.
On Mars it's much easier, as both carbon and hydrogen are abundant. SpaceX rightfully realized that for Mars you either need a very high ISP or a local propellant supply in order to have reasonable launch masses, and have opted for the latter with the Raptor LOX/Methane engine that they're working on. But that's just one of numerous possibilities on the red planet. A more unusual possibility involves the use of the abundant soil perchlorates as an oxidizer with any number of potential fuel species - they're easier to store than LOX and lower energy to produce (albeit lower performance).
** Likewise, when aluminum is added to a hydrocarbon mixture, the optimum ratio of oxygen, hydrocarbon and aluminum is one where the carbon only burns to CO, not CO2 - you want your carbon exhausts in a gaseous form, but your main goal as far as energy release goes is to burn the aluminum; the extra energy you get from carrying additional oxygen to fully burn the carbon is more efficiently spent carrying more stoichiometric mix of aluminum and oxygen for them to burn together.
Which is why we do that with airplanes, right? ;)
Musk provides the first pic. Actually, I expected worse. They can probably scrap this one for parts and send them off to destructive testing.
úff....
To be fair to the submitter, I think they just misinterpreted the news as meaning that the rocket didn't tip over and merely damaged a leg. That misinterpretation may be due to overoptimism on their part, but I'm not going to psychoanalyze them.
It did hit the bullseye, but it didn't have to.
Regardless, we now know that this incident was due to "Touchdown speed was ok, but a leg lockout didn't latch, so it tipped over after landing." The question is why the leg didn't latch.
Oooh, actual news:
Great to have the update. Not so great for whatever people were in charge with making, prepping, and inspecting the legs ;) Unless it was a design flaw.
I guess we have a new question now - why it didn't lock.
Because it has no crew and is remote controlled, with various automated features such as locking to specified GPS coordinates..
I'm not sure why you're confused about this.
New tweet from Musk, but no new news:
Even if we assume a perfectly stable platform, the fact that the drone ships are so much smaller than the ground landing pad means that the rocket has to do much more precise corrections to ensure that they land on it.
We'll find out soon enough what happened here.
No confirmation yet on explosion, though that sounds probable.
Indeed, I have trouble picturing it being intact and upright after a (quote) "hard landing" and with a broken leg.
Confirmation of Jason-3 separation. *Now* we can say that "SpaceX Sucessfully Launches Jason-3 Satellite".
Now let's wait for news on the landing...
Second burn completed successfully. Awaiting news of separation.