57
votes
Accepted
Why is Falcon 9's fairing so big?
One of the keys to SpaceX's cost advantage is standardization on common parts. One example is the Merlin engine, which is used on both the first and second stages of the Falcon 9 and Falcon Heavy (...
- 1,234
49
votes
Accepted
What are the pros and cons of Aerospike nosecones?
Aerospike nosecones have a couple of big benefits which, to fully appreciate, I'd need to give a little background on.
At the risk of dating myself, "Sherman, set the WABAC machine to the 1950s":
...
- 596
38
votes
Why are the bottom of most stages flat?
Surely, a passive trailing end of an aerodynamic body should optimally be more of a "tip". A classic example: space shuttle transported by airplane would get a "tail cone" over the engines to reduce ...
- 54.9k
36
votes
Could a helicopter fly on Mars?
There's nothing like seeing it flying in a Mars-density chamber to answer your question:
Crazy Engineering: Mars Helicopter
I have a really nice video of it in controlled flight in the chamber, but ...
- 58.5k
34
votes
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Could a helicopter fly on Mars?
Gravity is about a third of Earth's and competitive aerobation helicopter models have a truly excessive power surplus. Just look at this.
There won't be any manned helicopter flight. The helicopter ...
- 54.9k
31
votes
Accepted
Golfball Dimples on spaceships (and planes)?
The dimples on a golfball is structurally the simplest iteration of a vortex generator. Vortex generators are most definitely used in practice to improve aircraft performance. (for some usage examples,...
30
votes
Accepted
Soyuz Steering during Re-Entry
By itself the roll doesn't generate lift. But the Soyuz descent module (DM) enters with a non-axial center of mass that results in a non-zero angle of attack, and hence some lift. Several spacecraft, ...
- 18.2k
29
votes
Accepted
What is the most aerodynamic Satellite?
The only satellite I know of that was shaped to have low drag was GOCE, which orbited at 250 km.
Since it was vital to ensure that the measurements taken are of true gravity and not influenced by any ...
- 126k
25
votes
How would a long pole be transported to space?
The ISS solar array masts are launched collapsed in canisters, and run through a deployer mechanism to erect them as a long straight object. I see no technical reason why a much longer mast couldn't ...
- 178k
25
votes
Is this egg-shaped nose cone a good, aerodynamic design?
Rocket noses come in all sorts and sizes. The driving factor is more likely to be functional than purely aerodynamic.
For example, the shown Saturn V has a pointy nose, because that nose is wearing a ...
23
votes
How would a long pole be transported to space?
Long rigid structure can be transported as raw material for fabrication in space, in the same way that continuous rain gutters are made.
In the pictures below, you can see a machine that creates the ...
- 331
22
votes
What causes a rocket to be destroyed during launch other than leaking fuel?
I want to focus on aerodynamic stress however, like when a rocket deviates from its path or has a wrong angle of attack, what causes it to be destroyed?
In many cases, it's not aerodynamic stress. ...
- 73.2k
21
votes
What are the pros and cons of Aerospike nosecones?
You'll notice it is used on submarine launched ICBMs.
Blunt noses are very efficient for the missile to get out of water (and are shorter than long, profiled ones, which helps with submarine diameter),...
- 311
20
votes
Accepted
How long does Max-Q last?
"Maximum Q" is technically instantaneous, but less formally it can refer to a period of time where pressures are nearly at maximum.
Here's a graph of dynamic pressure for a simulation of the Saturn ...
- 167k
19
votes
Accepted
How high could Ingenuity fly?
While Ingenuity would theoretically eventually hit a "service ceiling" above which the atmosphere is no longer dense enough to provided a TWR (Thrust-Weight-Ratio) of above 1, I suspect the ...
- 18k
17
votes
What are these tiny triangular fins on the Soyuz launcher?
The Soyuz (booster) User's Manual from Arianespace calls them "aerofins" and says they are part of the attitude control system.
An additional image I ran across showing the aerofins and stating that ...
- 178k
17
votes
Would a dimpled heat shield reduce heat transfer during reentry?
The dimpled sphere may produce lower drag (though as Uwe points out I’m not sure if that is true in hypersonic flight). However, this does not mean that it will be better at surviving reentry.
Higher ...
- 2,267
17
votes
Accepted
Can a reentry be done slowly?
Not without propellant. Or at least not easily. However the "why" is a bit tricky.
This is far from the whole story but one of the problems is that generating enough lift to keep you from diving too ...
- 3,412
17
votes
Accepted
How would a long pole be transported to space?
Best way to do this could be to research, develop and send a "3D tube printer satellite" to low Earth orbit, and feed it with whatever material in liquid, powder or filament form, which will not ...
- 4,218
16
votes
How do we control a Reentering Capsule in the denser part of the atmosphere?
The entry vehicle for the Apollo missions is the command
module (CM), which has a symmetric body with an offset center of
gravity (c.g.). This offset c.g. causes the CM to trim
...
- 178k
15
votes
Accepted
Testing flight characteristics before actual flight in model rockets?
For simple stability, you need the center of gravity to be in front of the center of pressure.
You can find the center of gravity by hanging the rocket from a string with a loop that slips along ...
- 178k
14
votes
How long does Max-Q last?
As the other answers say, the actual peak of dynamic pressure is an instaneous point, but actions taken around this time are often described in terms of Max Q. For example, Space Shuttles would ...
- 178k
14
votes
Accepted
Why not jettison the nose-cone from Falcon Heavy side boosters for better control authority?
Getting rid of the nose cones would make things worse, not better. The reason the nose cones allow less control than the typical F9 (or FH center core) is because the cylinder of the rocket usually ...
- 1,542
14
votes
Could rockets launched from the ground use wings in the stages?
Could a slower or smaller rocket take advantage of lift if all the stages had wings?
Wings on the first stage can be useful; the Pegasus air-launched rocket has wings on its first stage that provide ...
- 167k
14
votes
How do we control a Reentering Capsule in the denser part of the atmosphere?
For Gemini, Apollo, and Soyuz capsules, lift is achieved by offsetting the center of gravity of the reentry module from the center line of the craft. This is represented in your diagram by the "...
- 167k
14
votes
Is there a mathematical formula to calculate drag force without empirical testing?
I am wondering whether there is a mathematical formula that we can use to calculate the drag force without empirical measurements.
Yes, much modern rocket design is done with Computational Fluid ...
- 167k
14
votes
Is this egg-shaped nose cone a good, aerodynamic design?
I'd always assumed that the more straight-edged cone-shaped nose had been found to have the most favourable aerodynamics for a rocket to take flight.
There's a key problem with sharp-nosed tips: They ...
- 73.2k
13
votes
Accepted
Purpose of hemisphere under shuttle nose cone (Enterprise)
That's an easy one.... S Band Antenna.....
This image comes from the document JSC-13864 SPACE SHUTTLE ORBITER
APPROACH AND LANDING TEST FINAL EVALUATION REPORT. It is on page 134 of the pdf.
Here ...
- 757
13
votes
Gliding into the atmosphere
It most certainly won't hurt anything. From FAA's document on returning from space, there is a very interesting chart, which I've included below.
So the maximum g load is almost always at around 4500 ...
- 121k
13
votes
Why not jettison the nose-cone from Falcon Heavy side boosters for better control authority?
They needed to upgrade the grid fins anyway, this is one of the modifications intended for Block 5. So the new grid fins were available.
This meant the choice is between:
switching to more ...
- 126k
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