This is frankly mesmerizing. And there is a surprise guest:
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Video: “If rockets were transparent”
- Thread starter e-FTW
- Start date
Thanks, that was very interesting. It took me a bit to understand what I was looking at, and then I realized the animation was showing the fuel and oxidizer tank levels as the were depleted on the way to orbit.
I did not realize that the SLS abort tower was jettisoned so much later than the Apollo tower was.
I did not see a “surprise guest” during the animation. Or are you referring to the FH payload?
I did not realize that the SLS abort tower was jettisoned so much later than the Apollo tower was.
I did not see a “surprise guest” during the animation. Or are you referring to the FH payload?
Same here! I guess the Apollo upper stage had more abort delta-V than SLS’?
One thing that bugged me was how both the STS and SLS boosters were done and jettisoned at the same time. Pretty sure the SLS ones have more sections and are taller, which I thought meant a longer burn. Unless they burn differently/faster in the SLS application.
Stil,l pretty darn cool video!
I was. ;-)
I would not assume that video is completely accurate.
I just realized I used the wrong tense. Instead of “was” I should have written “will (assuming SLS ever flies”.
I would not assume that video is completely accurate.
I just realized I used the wrong tense. Instead of “was” I should have written “will (assuming SLS ever flies”.
The video is definitely off on timing. The Falcon 9 second stage only lasts until five minutes in the video where we know from a zillion launches that it shuts down at around eight minutes - a few seconds after the booster lands.
The shuttle SRBs carried solid fuel. See Space Shuttle Solid Rocket Booster - Wikipedia
Quote from Wikipedia: “The SRBs were the largest solid-propellant motors ever flown and the first of such large rockets designed for reuse.[citation needed] Each is 149.16 ft (45.46 m) long and 12.17 ft (3.71 m) in diameter. Each SRB weighed approximately 1,300,000 lb (590,000 kg) at launch. The two SRBs constituted about 69% of the total lift-off mass. The primary propellants were ammonium perchlorate (oxidizer) and atomized aluminum powder (fuel), and the total propellant for each solid rocket motor weighed approximately 1,100,000 lb (500,000 kg). (Further details can be found in the description of the SRB propellants below.) The inert weight of each SRB was approximately 200,000 pounds (91,000 kg).
Primary elements of each booster were the motor (including case, propellant, igniter, and nozzle), structure, separation systems, operational flight instrumentation, recovery avionics, pyrotechnics, deceleration system, thrust vector control system, and range safety destruct system.”
Quote from Wikipedia: “The SRBs were the largest solid-propellant motors ever flown and the first of such large rockets designed for reuse.[citation needed] Each is 149.16 ft (45.46 m) long and 12.17 ft (3.71 m) in diameter. Each SRB weighed approximately 1,300,000 lb (590,000 kg) at launch. The two SRBs constituted about 69% of the total lift-off mass. The primary propellants were ammonium perchlorate (oxidizer) and atomized aluminum powder (fuel), and the total propellant for each solid rocket motor weighed approximately 1,100,000 lb (500,000 kg). (Further details can be found in the description of the SRB propellants below.) The inert weight of each SRB was approximately 200,000 pounds (91,000 kg).
Primary elements of each booster were the motor (including case, propellant, igniter, and nozzle), structure, separation systems, operational flight instrumentation, recovery avionics, pyrotechnics, deceleration system, thrust vector control system, and range safety destruct system.”
As @ecarfan notes they carry solid fuel. There's a lot of value in solid fuel motors, primarily because they can provide huge thrust relative to similar size/cost liquid motors. A side benefit is that they're more or less shelf stable and pretty robust from a handling perspective--that's one of the reasons a lot of (if not almost all?) wartime missiles are solid fuel. Solids are also way cooler to watch/feel.
Flip side, solid fuel is mass inefficient, which is why you don't often see them used as the orbital stage for a payload launcher (the only ones that come to mind are the Minotaur family and they're basically repurposed ICBMs so they don't count). Where solids are most effective on an orbital launch system is the initial mission phase when the rocket is the heaviest and needs the most thrust. While solids are obviously not the only solution or even the best solution given current technology (Merlin/Raptor, BE4), solid motors typically augment--to a significant degree--a liquid first stage like we see on At5/Vulcan, Ar5/Ar6, D2, STS/SLS, etc. There are two major benefits:
1. For some launchers the ability to change the number of solid motors enables a tunable/flexible launcher capacity. For instance, Atlas 5 can use from 0 to 5 solid motors and Ariane 6 can use 2 or 4, and for both systems the high end configuration ~doubles (+) the mass lift of the low end config.
2. For all launchers, a huge benefit of solids is that their low altitude workload allows the liquid motors to be optimized for higher altitude. That makes operation at those higher altitudes--after the solids have flamed out--more efficient (obviously), which improves overall system capacity. For some maths, each A6 solid booster (which, BTW, is also the first Vega stage) is ~3x the thrust of the core stage. Even for the "small" 62 configuration the Vulcain motor on the core stage is only providing a max of ~15% of the total thrust during initial ascent. So...even if the liquid motor has crappy efficiency at high atmospheric pressures (because it was designed for better efficiency at low atmospheric pressures) it doesn't make much of a difference in total system capacity.
The solid boosters on the Space Shuttle burn for 127 seconds, on the SLS 126 seconds. The SLS has one more segment, but the burn is from the center of each section outward, not along the length, which all burns at the same time. I built a CubeSat at Vermont Tech that was launched on the all solid Minotaur 1. The first photo it took ($20 camera) of the North coast of Western Australia:
tsmithlxix
Member
So more thrust if more segments are burning at once?
Awesome pic, you must have that mounted on a wall somewhere!
Pretty much, at more or less a proportional increase in thrust (Thrust is ~proportional to mass flow). I'm sure there's also laundry list of small improvements here and there that have been lying around for years that will also improve performance and/or <cough> decrease cost...
For a little blast for the past, I just remembered that SLS is really just a more expensive derivative of Ares, the STS-derived super heavy from W's moon program. That one only used 4 segment STS SRBs and Delta 4's RS-68. Obviously 5 is better than 4 (not as good as 11, but I digress) so that math checks out on the solids in favor of SLS, and since SLS's RS-25's are apparently whittled out of a single ingot of gold (compared to the poor person RS-68's that are only Au dipped), they certainly get the current administration's seal of approval.
Yeah, but its a little complicated to visualize in an animation, which is why they probably didn't bother. A solid rocket is basically a tube like any other rocket with a bunch of fuel solidified on the inside--a reasonable visual but not quite accurate analogy is that a piece of wood is solid fuel. The twist is that there's a hole (or some more complicated cross sectional shape) that runs up through the middle of the solid fuel basically from the nozzle at the bottom to the nosecone at the top...kinda like if you bored a hole through the length of a log. The solid fuel then burns from the inside out and, kinda like that log with the hole burning from the inside out, its really hard to animate that from the outside looking in.
adiggs
Well-Known Member
It must be hard to get an ingot of gold at that size to whittle down.
On the plus side, I expect it's easy to get janitors to clean up after the sculptors.
