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Questions tagged [max-q]

The point during the launch where the aero-dynamical stress on the launch vehicle is highest.

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3 answers
1k views

How is max Q for the shuttle actually defined?

In this article about max Q https://en.m.wikipedia.org/wiki/Max_Q the shuttle launch is discussed. Since there are four distinct large objects - two boosters, one shuttle and one giant tank - there ...
5 votes
1 answer
184 views

Would max-Q coincide with the loudest/roughest part of the flight?

Say you're an astronaut on a ride to the ISS, and you have with you a very accurate clock, an automatic pressure sensor, and a high quality microphone. If you synchronized the sensor and microphone ...
7 votes
2 answers
1k views

What was the actual Q-alpha limit for Saturn/Apollo launches, and what was the typical max Q-alpha?

Organic Marble's answer to a previous question about Apollo abort limits clarified that the figure of concern was the product of dynamic pressure (Q) and angle of attack (alpha), with the 100% level ...
11 votes
1 answer
451 views

Why making such a big deal with Max Q?

At each SpaceX launch, they always make some big deal of Max Q which most of the time comes at around 13Km and at a speed of 1700Km.h-1 But on the way back, stage 1 is at this same altitude of 13km at ...
15 votes
2 answers
3k views

Could one survive a ride into orbit outside a rocket?

Another question asked whether a Falcon 9 class rocket could reach orbit with a person (-like mass) duct-taped to the outside of it, in spite of the resulting mass asymmetry. The consensus of one ...
0 votes
1 answer
133 views

When did the Astra Space test flight 006 actually reach max-Q? There is substantial disagreement in the audio feed of the launch (Launch Vehicle 0006)

Watching the NASA Spaceflight video Astra Test Flight (Launch Vehicle 0006) linked below it seems the launch was terminated, but at least on the video there was no audible Earth-shattering kaboom. ...
2 votes
1 answer
570 views

Does MAX Q during rocket launch only say that rocket experiences max dynamic pressure? [duplicate]

I know that during rocket launch, one main event that occurs is MAX Q where the rocket experiences maximum dynamic pressure which is simply (1/2)ρv^2. I also know that drag coefficient of rocket ...
7 votes
0 answers
213 views

How is the Max-Q of a spacecraft determined?

Maximum aerodynamic pressure of a spacecraft is the maximum force it's hull can withstand during flight. How is the Max-Q of a spacecraft determined? Other related ( optional) queries are: If Max-Q ...
2 votes
1 answer
387 views

Why the max dynamic pressure might not happen at maximum drag instant?

I understand that is that when a rocket accelerates the drag force grows dramatically since the force is related to velocity squared. But, at the same time, the density is decreasing, so the force is ...
3 votes
2 answers
825 views

Falcon 9 Max Q on reentry?

Max Q for a Falcon 9 is on the order of 30-40 kPa during launch. What would the number be on descent? Do they allow for greater dynamic pressures in that portion of the flight? Or is the rocket still ...
2 votes
0 answers
193 views

How much lower is max q if launching from high altitude (i.e. mountain top)?

I looked at very simple max q formula: q=1/2 ρv^2 (https://en.wikipedia.org/wiki/Max_q). As air density is lower with altitude, the max q should be lower as well, and also should occur at higher ...
31 votes
4 answers
3k views

Has Max-Q historically been a common failure point in rocket launches?

I believe that it's common knowledge that Max-Q is the point in which a rocket is undergoing the maximum dynamic stress during a launch and ascent. But, how often have rockets actually been destroyed ...
26 votes
6 answers
10k views

Why aren't rockets built with truss structures inside their fuel & oxidizer tanks to increase structural strength?

I've been wondering how a rocket fuselage can support all the weight of the upper stages when it is only made of a cylinder of very thin sheet metal. (Especially considering acceleration, vibration ...
2 votes
0 answers
140 views

Max Q vs Prandtl-Meyer Fan

Does Max Q occur before or after the Prandtl–Meyer expansion fan? The shape, nature's way of avoiding a single shock wave (per Wikipedia) is visible on the Apollo launches for example. Apollo 11, ...
3 votes
0 answers
46 views

Proton K or M altitude at Max-Q

I'm trying to fill out a sketch table as part of a research project, and I've run into a bit of a snag. Hopefully someone here can help me out. I'd like to know the altitude of the Proton K or M ...
8 votes
1 answer
3k views

What percentage of overall fuel does a rocket burn up to get to max-q?

I know that max-q normally occurs around 11-15km (based on observations of watching falcon 9 launches and this). Furthermore, I know that the fuel usage for each rocket would vary a lot (which I ...
2 votes
1 answer
2k views

Is it possible to calculate Max-Q without having to input an altitude

Is it possible to calculate max-q based on just upwards velocity instead of specially inputting a given altitude/air density? Based on this graph of Falcon 9 launches till MECO below "Air Pressure vs. ...
9 votes
1 answer
1k views

Just how much can tall skinny rockets bend? (roughly, safely)

Below is a GIF I prepared and used in an earlier question, and the answer seems quite reasonable. With a height to diameter ratio of about 70 m to 3.7 m (nearly 20:1) a weight-conscious design, ...
7 votes
1 answer
769 views

What will Max Q for descent be? [duplicate]

I've seen lots of flight profiles that give Max Q during ascent. Around 33 to 35 kilopascals, if memory serves. But I have been having a hard time finding Max Q during descent. With the recent reuse ...