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56 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 (...
SafeFastExpressive's user avatar
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": ...
Steve's user avatar
  • 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 ...
SF.'s user avatar
  • 55k
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 ...
Mark Adler's user avatar
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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 ...
SF.'s user avatar
  • 55k
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,...
SE - stop firing the good guys's user avatar
30 votes
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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, ...
Tom Spilker's user avatar
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29 votes
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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 ...
Hobbes's user avatar
  • 128k
26 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 ...
CuteKItty_pleaseStopBArking's user avatar
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 ...
Organic Marble's user avatar
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 ...
Jim's user avatar
  • 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. ...
David Hammen's user avatar
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),...
Khay's user avatar
  • 311
20 votes
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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 ...
Russell Borogove's user avatar
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 ...
Dragongeek's user avatar
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18 votes
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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 ...
ANone's user avatar
  • 3,442
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 ...
Quentin Clarkson's user avatar
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 ...
Organic Marble's user avatar
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 ...
Organic Marble's user avatar
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 ...
Organic Marble's user avatar
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 ...
Organic Marble's user avatar
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 ...
CBHacking's user avatar
  • 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 ...
Russell Borogove's user avatar
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 "...
Russell Borogove's user avatar
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 ...
Russell Borogove's user avatar
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 ...
David Hammen's user avatar
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 ...
Challenger Truth's user avatar
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 ...
Hobbes's user avatar
  • 128k
13 votes

Merging Shuttle and External Tank to reduce reentry heating

It would make reentry heating much less stressful, but would make landing the 7-times-larger-volume vehicle a royal pain, and would greatly increase the surface area that needs to be insulated. And to ...
CuteKItty_pleaseStopBArking's user avatar

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