Hot answers tagged

38

Keeping a burnt-out stage attached doesn't hurt until it's time to start the next stage. In fact, keeping it attached until shortly before it's time to ignite the next stage can improve the total launch delta V. Stage three separation occurred at an altitude of 184 km. There's still air up there. It's not very dense air, but for a vehicle going at close to ...


33

It’s a sense of scale issue. As much as the struts might look like flimsy bits of drainpipe, those rockets are around 15 meters wide, and the struts are more like the heavy steel beams used to hold up entire buildings. So yes, they’re just really strong.


29

Yes. (Image source) Some configurations of the Delta II used nine solid boosters. In launches from both the ER and WR, the first-stage RS-27A main engine and six of the nine strap-on solid-rocket motors are ignited on the ground at liftoff. Following burnout of these six SRMs, the remaining three are ignited. Delta II ...


26

The starboard booster was ignited two seconds earlier as an attempt to diminish the fireball effect noticed in earlier launches. William Graham of NASASpaceflight.com says: The effect – caused by the rocket’s exhaust igniting hydrogen vented near the rocket – has scorched or even set fire to the first stage insulation on previous flights. While it has ...


23

The Soyuz line all the way back to the R-7 has straps or cables connecting the boosters to the core. The straps, plus a "socket" on the core catching the front tip of the booster, are apparently how they're held on. One of the straps, near the base of the booster, is shown highlighted in blue here: This RussianSpaceWeb page has a rendering of the boosters ...


23

These boosters are called “strap-on” because there is little structure besides the separation mechanism holding them on, and the rocket is still a viable launch vehicle without them. In a few designs, like the Atlas V, the number of boosters can be customized per-mission. Also, in some cases the booster design is shared between launchers like the Shuttle and ...


22

For Delta IV Heavy, according to Spaceflight101: The CBCs functioning as boosters are attached to the central core using thrust struts that interface with the interstage section of the launcher to transfer loads from the boosters to the rest of the vehicle. Additional attachment points reside in the base of the vehicle right above the engine heat shields. ...


18

The Soyuz uses conical boosters because there's an aerodynamic advantage. According to The Red Rockets' Glare: Engineers gravitated to a conical shape primarily because of the aerodynamic advantages ...but also for 3 other reasons: the large size of the engines at the tail end, the possibility of imparting additional thrust to the central sustainer ...


17

Offered as a supplement to the other answers, here are some data about SRBs thrust profiles and operation. Thrust of a SRB is function of the area of the solid fuel burning, as shown below: You can find here how the space shuttle SRBs are filled: The propellant had an 11-point star-shaped perforation in the forward motor segment and a double-truncated-...


16

The SRBs are pretty close to burnout when they separate: SRB separation is initiated when the three solid rocket motor chamber pressure transducers are processed in the redundancy management middle value select and the head- end chamber pressure of both SRBs is less than or equal to 50 psi. A backup cue is the time elapsed from booster ignition. ...


16

The claim may be based on a misunderstanding. The solid rocket boosters are made in Utah and transported to the launch site in 4 segments by rail, which does limit their size. But it's not the track gauge that determines this limit, but the the loading gauge, which is only very indirectly related to the track gauge. However, the diameter of the shuttle ...


16

The coasting period is certainly to perform a Gravity Turn. It is a trajectory optimization that uses gravity to steer the vehicle onto its desired trajectory. ... the thrust is not used to change the ship's direction, so more of it is used to accelerate the vehicle into orbit. Once the vehicle has coasted into the right angle, P4 ignition takes ...


16

Solid fuel ramjets exist The problem for a launch system is you would need a lot of oxidiser anyway — ramjets only start to produce thrust from Mach 1.5–2. They also start to lose thrust above Mach 4–5. Add onto this the huge amount of intake air that would be needed for a system with a high thrust/weight ratio and the complexity of ...


16

An advantage to using a coaxial tank is you don't need to arrange plumbing to get the upper tanks contents to the engine. A big problem with a coaxial tank is the large surface area between the two tanks, which means your propellants have to have compatible operational temperatures, or you need a lot of insulation. In practice most rockets use cryogenic ...


15

Your assumption that rotating the rocket removes asymmetry is incorrect. The total thrust of the rocket can be visualized as a vector. This vector should point at the center of gravity of the rocket. If it doesn't, the thrust will change the direction of the rocket. It's easy to see that a rocket with 1 booster will not have its thrust vector pointing at its ...


13

The jettison of spent boosters depends on a number of factors like the design, safety etc. The Japanese H-IIA has a rather unique design, where the thrust developed by the solid fuel rocket motor (SRB-A) passes through the thrust struts and is received by the lug which forms an integral part of the cross beam fixed on the LE-7A engine. Image from ...


13

Local scrap metal dealers collect and recycle them. See this link for some more information.


13

Image source The booster has two kinds of joints between its segments, field joints and factory joints. The booster parts shipped to KSC were made up of two segments joined by factory joints. At KSC, these parts were put together using the field joints. There are three field joints and seven factory joints in a Shuttle SRB. Image Source Both kinds of ...


12

Partial answer: the ammonium perchlorate is manufactured in the western United States. The two perchlorate manufacturing facilities located in Henderson, the Kerr-McGee and the PEPCON plants, supplied the entire perchlorate demand for the United States until 1988, when the PEPCON plant was destroyed by an explosion. (note: Henderson is in Nevada) ...


11

Any rocket flight will involve a burn in it's final orbital position. If you want to enter a 500km orbit your engine will shut down at 500km up. The profile shows it needs nearly 19 minutes to reach altitude but the rocket burn times only add up to 15 minutes. You can't magically make it get there in 15 minutes because you don't have extra fuel. Thus the ...


11

The main engine on the Atlas, as with most orbital launchers, is gimballed such that it can direct thrust to offset the imbalanced thrust from the boosters (or any other disturbance). Atlas uses only as many boosters as it needs for a given payload -- from zero to 5 -- and some of those configurations are asymmetrical. It looks especially odd using only a ...


11

First issue is that even though Falcon Heavy is claimed to have a max payload of 50,000+ lbs to LEO, it turns out the payload adapter is much more limited, with two models, the bigger limited to 24,000 lbs range. Second issue is that the fairing is volume limited, today, and increasing the payload would not help, since the density is usually not high ...


11

Titan 34D boosters had thin, strappy looking attachments (but they were probably actually struts vs. straps). I always thought the upper attachments looked odd. They must have only been to resist lateral forces, with all the thrust force being transmitted through the aft ones.


11

'Loaded' means it's loaded with propellant (as opposed to something like 'inert' or no marking at all, for casings that have not been loaded). It's used to make it easy to distinguish which casing segments have been loaded with propellant and which ones haven't. Loaded segments require different handling procedures than non-loaded segments. In the military,...


11

Besides the Delta II and PSLV-G/PSLV-XL, there are a few proposed/in-development stages that would fire 7 engines at once. Blue Origin’s New Glenn booster is designed with 7 BE-4 engines powering its first stage. ULA has put forth a paper design for a “Delta Super Heavy”, 6 boosters surrounding the central first stage core of the Delta IV. I don’t know if ...


10

Kerbal Space Program, the video game, teaches us that it is most effective to thrust at apoapsis (highest point of orbit) to increase our periapsis (lowest point of orbit). Waiting to fire the next stage there will make better use of fuel. Note that you want all the force applied at apoapsis, so you want to burn a little before and after it, since it is a ...


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

Pneumatic "pushers" (rather than traditional explosive pyrotechnics used by most rockets) are used to separate the boosters on the Falcon Heavy. There's probably some electrically operated, large mechanical latches holding them together beforehand. By activating the pushers at the top of the booster before the bottom, the booster is tilted away from the ...


10

No, they're on a separate ship (a tug boat) nearby. This tug tows the barge into position, then detaches so the barge can use its own motors for positioning and retreats to a safe distance for the landing.


10

For French and Ariane 5 Several names are used. EAP is the most common one « Étage d'Acceleration à Poudre » which could be roughly translated to « acceleration powder stage» An other more generic term used is « propulseur d’appoint » which translate to « complementary propulsion device » For Japanese and H-IIA Take this with a grain of salt my ...


Only top voted, non community-wiki answers of a minimum length are eligible