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50

The rocket is autonomous, it flies itself. The navigational math, engine, and flight dynamics of a Earth-based orbital class rocket in operation are far too complex for manual operation, especially remote manual operation. Even simpler rockets (like Apollo LEM) that could be flown manually have still attempted to offer automatic operation in the interests ...


39

Elon Musk made reference to the "Holy Mouse Click" that happens right before they start loading fuel. From that point forward, the rocket will launch itself at the planned time, about 2 hours in the future, unless something happens that stops it prematurely. I'm not sure if there are other prompts that are required, but things are pretty automatic. In ...


36

As with most things space, it all comes down to tradeoffs. The most efficient rocket is one that is purely expendable and has no mass that does not contribute to getting the payload towards orbit. If the aim is to reuse the rocket, you need a mechanism to achieve control in the upper atmosphere, a method to control descent rate and a method to achieve a ...


16

I think this is pretty self-explanatory: (Thanks to @TildalWave for finding an updated graphic) It's important to note that the landing pad was a different site to the launch pad (6 miles away), so it didn't return *exactly* to its' original point of take-off, as can be seen here:


16

Wings are heavy. They also add mass to the rocket's structure, because it is loaded horizontally when flying with wings rather than vertically as it is at launch. At the time Energia was developed, control systems were not developed enough for a vertically landing rocket. However, now that we have that ability (as Blue Origin and SpaceX have demonstrated), ...


13

The "return to launch site" flight profile flown on December 21, 2015, requires that the first stage re-light three of its engines after separation, turn around, cancel out all its speed, and accelerate back towards the launch site. To do this, it has to keep a lot of fuel in reserve after the separation -- less than you might think, though, because the ...


13

Landing legs catching fire as they extend in the final second prior to landing isn't really unexpected, so they would be designed to withstand that. And this being potentially a problem unless engineered around it has already been made more than apparent during Grasshopper and F9R Dev test flights. Adiabatic flame temperature of RP-1 (rocket grade kerosene) ...


12

They have said that they will reserve around 15% of the fuel capacity of a first stage for reusability operations. At the point they need to impart the Delta-V to return to base, they will thus be 85% empty. Thus the need for only 3 engines instead of the 9 main engines for the retro propulsion burn. I won't try to do the math, but they claim they have, ...


10

The SRBs for the Shuttle and SLS are used to get the stack moving and off the pad, so that the more efficient LOX/LH2 engines can do the hard work. In the case of the Space Shuttle, an amazing amount of thrust is needed. I like using lbs of thrust because it is more inspiring. The SRBs produced 2.8 million lbs of thrust. That is just awe inspiring huge. ...


10

With the release of fairly detailed landing video for the CRS-6 landing attempt it is very clear that the legs do not deploy until 20 seconds at most before landing, so they are clearly not used as aero control surfaces. In fact it can be seen in the video that the legs deploy half way, then only in the last few seconds deploy all the way down. Elon Musk ...


8

Elon Musk said during the recent MIT AeroAstro Centennial Symposium (link to the video) that for the upcoming launch (CRS 5) he gives it about 50% or less chance of landing the first stage successfully on also recently announced floating platform, but if they do that he figures they'd be able to refly it. So the answer to your first question seems to be: no....


8

As of yet (December 17, 2014), there was no official announcement of live webcast of the Falcon 9 booster landing on the barge (aka autonomous spaceport drone ship). Here's SpaceX' latest update on this, stating: The odds of success are not great—perhaps 50% at best. However this test represents the first in a series of similar tests that will ultimately ...


8

The whole process is probably very human-survivable. The very end of the hover-slam is about 2g acceleration (dry mass of stage ~23 tons, single Merlin 1D rated at 723kN, throttled down to 70%, so 723 x 0.7 / 23 = 22m/s2 assuming it lands bone-dry). The boost-back is done on three engines but with some fuel remaining in the tanks. Our user Hobbes ...


7

Based upon the statement of 15% of fuel being reserved, and three engines used for the landing phase... and doing a simple "back of the envelope" kind of calculation... **Stock Data** 28.0 T Falcon 9 v1.1 dry mass (est) 5.0 T this author's wing-it for the landing legs on the v1.2 411.0 T Fuel Mass (est) 598.7 TT Full thrust (at MSL) 9 engine ...


6

The barge itself has an FCC license for its systems and antennae that do not seem to include anything powerful enough to send video live. However SpaceX has access to a jet (Elon Musks N900SX) and they know where the booster will be landing with greater accuracy this time, so it is within the realm of possibility. The support ship will be nearby and may ...


6

They are not used as aerodynamic surfaces during launch, but they are used to help balance the spacecraft and provide some control during the landing sequence. As to what level they will be used, only someone who works for SpaceX could tell you and they won't, but the Falcon 9 has full thrust vector control, not requiring external fins or other such items ...


6

Horizontal component of first stage velocity will be under Mach 6 or under 2,000 meters/sec as Elon Musk stated previously (in a Popular Mechanics magazine article from 2012) for recovery of his 1st stage. Remember that SpaceX announced F9R wind tunnel tests at NASA-Marshall up through Mach 5. Remember that overcoming gravity losses is ~ 1,500 meters/sec of ...


6

Wings won't work on the moon, and won't work nearly as well on mars. SpaceX is getting some practice in with the landings (note that recovering boosters is still in beta according to SpaceX) on the Falcon 9 before they build the Starship (Formerly known as the BFR) that will need to be able to land with no atmosphere.


6

There are several levels of automation on a SpaceX launch. Strictly speaking, full control to the rocket is only given 60 seconds before launch (start up sequence, look at any SpaceX launch webcast). Without, the rocket won't launch even if T-0 is reached without a single warning. With it, the rocket will launch on its own at T-0 unless the rocket itself ...


5

Pad infrastructure seems simple enough: just add plumbing for kerosene. You'd go from 2 to 5 boosters (with more thrust, so higher loads), attachment points won't match and you'd need to qualify the new combination of stages.


4

You're missing something obvious: Air friction. The terminal velocity, that is the speed, the rocket would have when air friction and gravity are in balance, is a small fraction of orbital velocities in a few kilometers altitude. So just by reentering the atmosphere, they kill almost all of their momentum. After reentry, they may also use aerodynamic ...


4

A suggestion (unsourced, floating around the NSF forums) is that they most likely will NOT refly the first recovered stage. But will rather take it apart to examine it in great detail. However, they may take parts that are otherwise redundant (Flight computers, electrical components, single engines) and reuse them on other flights. That is, use parts ...


3

The last water landing was about six miles down range from the launch site. About as close as they wanted to get. The goal is to come back to the same launch site, and have the mobile launch tower go and get it very soon after landing. This might be a few hundred feet from the assembly and launch site. I did see where the planned landing sight is at the ...


3

Live, no. But they did release the video today, only a few days after the launch. See this link, from SpaceFlightNow.


2

Remember on the way up those engine bells are taking an amazing amount of heat from burning LOX and RP1. They can handle a LOT of heat. On the way down, they take most of the heat on the engine bells, designed to take it, and then the components above it, are the ones with protection. SpaceX has been iterating and evolving the materials and equipment to ...


2

Your question "But could those creatures get married rationally?" is a good one. Rationally - sort of. The answers here that refer to thrust forget the solid rocket boosters have to lift themselves. If you run the numbers (try the "Silverbird" tool on the web for ROM purposes) you will get the 70t payload to LEO for an approximate description of the SLS (...


1

I do not have a quote to source it, but recall Elon Musk saying it was on the order of a 100 lbs of fuel and oxidizer left. Almost dry, but clearly enough to burn.


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