35
votes
Accepted
Why does the Indian PSLV rocket have tiny boosters?
Why would these be used instead of just using a larger first stage?
Strapping on differently-sized boosters allows variance in payload mass without redesign of the first stage. The PSLV has flown with ...
- 174k
34
votes
Accepted
Why do the walls of a solid rocket booster not glow red hot?
Solid fuel does not burn unless it has been vaporized by heat from combustion. The boundary between solid and gaseous fuel is located at the point where the temperature equals the fuel vaporization ...
- 15.3k
33
votes
Accepted
How is thrust transmitted from strap on boosters to the central core?
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 ...
- 2,257
33
votes
Accepted
Why are Starship landings so difficult when SpaceX has landed so many boosters?
There are a few reasons:
The most obvious but easier to overcome is that the Starship is new. They haven't had the time to perfect everything. For example, the Raptor engines use two separate ...
- 446
30
votes
Have there been any rockets that run seven engines at the same time?
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 ...
- 174k
26
votes
Why do the walls of a solid rocket booster not glow red hot?
Simply - even a very thin layer of fuel is enough to isolate the heat. So only in the very last seconds will there be not enough fuel to isolate the heat flux.
Then there is a liner between the fuel ...
- 1,003
24
votes
Accepted
Are any "strap-on" boosters held in place by actual straps?
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 ...
- 165k
23
votes
Why "strap-on" boosters, and how do other people say it?
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, ...
- 2,917
22
votes
How is thrust transmitted from strap on boosters to the central core?
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 ...
- 165k
21
votes
Accepted
What is the difference between the solid fuel Boosters of the Shuttle and Artemis?
(This answer assumes the the SLS SRBs are the same as the Five-Segment Boosters (FSBs) studied for a shuttle upgrade...I believe they are, but have not seen this explicitly stated).
The thrust time ...
- 174k
20
votes
For a typical Shuttle mission, how much solid fuel is leftover at SRB separation?
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 ...
- 123k
18
votes
For a typical Shuttle mission, how much solid fuel is leftover at SRB separation?
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 ...
- 2,040
15
votes
Accepted
Features seen on the Space Shuttle's solid booster; what does "LOADED" mean exactly?
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,...
- 174k
13
votes
Accepted
How does Atlas V maintain stable flight with asymmetric solid rocket boosters?
The nozzles of the SRBs are canted outward, so the line of thrust from each SRB passes close to the center of mass of the rocket, so that the net torque from asymmetrical booster arrangements is ...
- 165k
13
votes
Why do some rockets jettison their boosters much after they are burned out?
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 (...
- 1,560
13
votes
Features seen on the Space Shuttle's solid booster; what does "LOADED" mean exactly?
'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 ...
- 123k
13
votes
How is solid rocket fuel sourced?
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, ...
- 174k
13
votes
Why are Starship landings so difficult when SpaceX has landed so many boosters?
The experience of landing a booster for SpaceX is actually more relevant directly to the Super Heavy booster, which has yet to fly. (BN1 was built as a pathfinder, then disassembled. BN2 is under ...
- 78.9k
13
votes
Accepted
What are the advantages of air lit solid boosters in PSLV XL?
This probably has to do with optimizing the launch efficiency of the rocket.
More specifically, a rocket has two goals:
Get out of the atmosphere
Reach orbital velocity
The second step can't really ...
- 16.7k
12
votes
Are any "strap-on" boosters held in place by actual straps?
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 ...
- 174k
12
votes
Have there been any rockets that run seven engines at the same time?
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 ...
- 165k
11
votes
For a typical Shuttle mission, how much solid fuel is leftover at SRB separation?
This is the tail end of the thrust graph given in Hobbes' answer:
I've added guidelines showing the point where thrust falls below the 60,000 lbf point, about 2.7 seconds before it hits zero.
The ...
- 165k
11
votes
Could the solid boosters of SLS be replaced by reusable Falcon 9 first stages?
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 ...
- 78.9k
11
votes
Would a hex-cluster of SpaceX boosters around a central booster lift a large payload into space?
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,...
- 78.9k
11
votes
Accepted
SpaxeX employees on the droneship when the booster lands?
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 ...
- 123k
11
votes
Why "strap-on" boosters, and how do other people say it?
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 ...
- 12.5k
10
votes
Accepted
What is used to connect the side boosters to the first stage?
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 ...
- 165k
10
votes
Accepted
When was the first strap-on booster used in spaceflight?
Boosters were in use by 21 August 1957, the first successful suborbital launch of the R-7.
Definition of 'booster':
A booster rocket (or engine) is either the first stage of a multistage launch ...
- 123k
Only top scored, non community-wiki answers of a minimum length are eligible