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SpaceX's Latest Launch Successful, But Ends With a "Hard Landing" (theverge.com)
Eloking writes with this news from The Verge: SpaceX successfully launched its Falcon 9 rocket into space this afternoon, but — as expected — failed to land the vehicle on a drone ship at sea afterward. CEO Elon Musk said the rocket 'landed hard' on the drone ship. The mission requirements made a successful landing unlikely. This was SpaceX's fourth attempt to land the Falcon 9 post-launch on an autonomous drone ship floating in the ocean. All of the previous sea landings failed too, though the third attempt came very close. The company had low hopes of a successful landing from the start of this mission, since the rocket had to send a heavy satellite into a high orbit. That requires a lot of fuel for the launch itself, so there wasn't much fuel left for the rocket's return to Earth and powered landing.
SpaceX and Marco Rubio are duking it out to see who wins "best management of the expectations game." Personally, I'm gonna give "third place win" the edge over "successful failure," but that's just me. Good hustle all around guys!
Just because you sold your soul to the devil that needn't make you a teetotaler. --The Devil and Daniel Webster
Boom!
Don't waste your vote! Vote for whoever you want, unless you live in a swing state it won't matter anyways
Right now, both of the barges have horizontal thrusters that will keep the barges in 1 place. In that regard, it makes much easier for the craft to come down. However, the barges do not have vertical thrusters, so, they will pitch and roll in the same location. Without these, it is going to be impossible for these to land on the barge during heavy seas such as what was seen. On a calmer day, with say 1 m waves and under, the stages will do just fine.
I prefer the "u" in honour as it seems to be missing these days.
They can do a landing on solid ground (or at least they have done it once). Unfortunately, there is no solid ground in the right place for most flights
The rocket is not designed to handle stress from all angles. Flopping into a net would entail coming down hard in a direction that it is not designed to handle stress. The primary advantage of a vertical landing is that most of the stress remains vertical just like when the rocket is being launched. Building it to handle other directions would require much more mass. They'll get this to work eventually, and this was a very difficult run anyways because the orbital profile required the rocket coming down from higher up, at a higher velocity and with less fuel to work with. Please be patient.
It's all about the fuel. On launches that leave enough spare fuel, they actually return the rocket all the way back to a landing pad at the launch site in Florida. They successfully landed the rocket once in that manner. But on launches that require more fuel (to put a heavier payload into a faster orbit), there isn't enough fuel leftover for the burn that would send the rocket back towards the launch site. As a result, they are limited to a relatively ballistic trajectory from the launch site, which means landing somewhere out to sea. The landing destination is actually pretty precise (the drone ship is trying its best to stay stationary, not move to meet the rocket), it's just that it's the only place they have enough fuel to get to.
The first stage of the rocket never reaches orbit: it's still going really really fast, but not orbital velocity. So after the second stage separates, left alone, the first stage would start falling down again downrange and crash into the ocean.
Normally, after separation, the first stage flips itself over and then does a boostback burn to kill the forward momentum, and give it enough momentium backwards to line up its trajectory back towards the launch site. Then later it does a deceleration burn to slow itself down to keep the atmosphere from ripping it apart. And then finally, it does a landing burn for the last segment to slow it to a stop.
On some missions, they don't have the fuel to do that full boostback burn, so they kill some of the forward momentum, but that's it.
Actually their one successful landing was from a launch in Florida, but they had enough fuel to return to the launch site.
I think SpaceX will sell a lot more geostationary transfer orbit missions now. They've shown that they can do it with a pretty heavy payload: 5300 kg, and they delivered 1300 km greater apogee than promised.
Your cost figure for building a recovery platform is for one of them. So, suppose that one would work for GTO on F9. To limit the delta-V needed for recovery, you'd probably need another for GTO on F9H center stage, because it gets a lot higher and further downrange, one for LEO insertions that can't return to landing site, one for polar orbits from Vandenberg, one for the 51.6 degree inclination of ISS. You'd also need to permanently man them and sustain the expense of offshore maintenance. And you'd continue to need barges and ships to transfer rockets from them. So, this probably increases the per-launch staff and infrastructure expense significantly when SpaceX is trying to reduce that.
The rocket is a big narrow tube, yes, but it's quite bottom-heavy at landing. LOX is in the upper tank, and you can see from the Orbcom recovery video that they vent the LOX the instant the rocket sets down, so that tank is empty. RP-1 is at the bottom of the lower tank, and then engines are under that. The engines are the heaviest part. The rest of the rocket is equivalent in thickness and weight to a soda can scaled up to that size. Pressurization is used to keep it rigid during flight. So, I think the chance of tipping over, if the legs actually work correctly, is lower than many folks estimate.
Bruce Perens.