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Questions tagged [rockets]

Questions regarding the boosters or thrusters used to propel man-made objects.

93
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4answers
14k views

What is the purpose of having a countdown during a rocket launch?

Every rocket launch has a countdown. But what purpose does it serve?
68
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5answers
9k views

Difference between BlueOrigin and SpaceX rocket landings?

So, SpaceX has finally landed their booster back to the land. BlueOrigin has achieved the same thing in a recent past, but I have read so many people commenting and criticizing the comparison of ...
53
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6answers
8k views

Can a miniature Saturn V get to the moon and back?

If the Saturn V rocket along with its Apollo spacecraft was miniaturized, for example to 1/72 scale so it was five feet tall, could it still perform a moon landing like the Apollo missions and get ...
47
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4answers
5k views

How much bigger could Earth be, before rockets would't work?

hint: Apparently the Tsiolkovsky rocket equation does not actually say that you can launch a conventional rocket into orbit around an arbitrarily large and massive body. Question: "How much bigger ...
43
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6answers
5k views

What technological breakthroughs were required to land booster stages?

It is only recently that SpaceX developed first stages that can land again, and be reused. The (until recent) non-existent landing of re-useable rockets is presumably, partially, due to a lack of ...
38
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5answers
8k views

How do rocket scientists do iterative development?

In software, the general process for developing anything is code, test, fix, repeat. This is easy and cheap, because running a program typically costs an incalculably small amount of money. In rocket ...
38
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1answer
6k views

Do booster stages run out of fuel, or are they purposefully shut off?

When an expendable booster rocket stage nears the end of its burn, does the guidance computer shut the engine(s) off at a certain velocity/altitude for the mission, or does the stage completely ...
37
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5answers
20k views

Who coined the phrase 'Rapid Unscheduled Disassembly'?

Usually simply abbreviated as a RUD, and also sometimes expanded as Rapid Unplanned Disassembly, and being a way of understating that a rocket exploded. I saw it attributed recently to Elon Musk, ...
36
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2answers
6k views

Did the Saturn V rocket have any purely aesthetic features that didn't serve an actual function?

The rocket itself is magnificent, yes, but with so many ins and outs to it, curious if the entire design was solely purpose built, or if there were features specifically for aesthetic purposes.
35
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4answers
8k views

What “actually” happens at T-minus-0

In most American rocket launches, the "counter" will say: 3,2,1 [awkward pause], and liftoff.... So what truly happens at T-0? Is there any standardized event that this time indicates? Is the ...
35
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2answers
24k views

How realistic is Kerbal Space Program?

Kerbal Space Program is an independent spaceflight simulation game, which has become quickly popular due to being (kind of) precise at simulating actual spaceflights. But how precisely? How close is ...
35
votes
2answers
41k views

What is the vapour/smoke that comes from a rocket before launch?

While a rocket is waiting on the platform during the final countdown, it often seems to have clouds of steam or something similar escaping from it. Is this normal, and what are these clouds?
35
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1answer
5k views

Why does this rocket have a nose cone “cozy”?

A tea cozy keeps the tea in a teapot warmer longer by insulating it. Why does the nose of the rocket shown in Apollo-era file footage used in this video (lower your volume before watching) have a ...
33
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3answers
4k views

Do rockets, launch vehicles or spacecraft contain a black-box?

Like aeroplanes, do rockets also contains some black-box kind of thing to see what went wrong at the time of failure?
31
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4answers
9k views

Why is there a hole in solid rocket engines?

I would like to find out why there is a straight hole down the middle in all solid rocket engine motors. I thought it only makes sense in hybrid engines where pure oxygen needs to be blown down the ...
31
votes
6answers
9k views

Why do rocket nozzles open near the end?

Question: Why do rocket nozzles open wider at the end than, let's say, get narrower? Let me explain: I recently learned from random internet sources, that a jet engine works by having this amazing ...
31
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3answers
12k views

Why are hydrogen-fluorine fuels not used for rockets more frequently?

Many rockets use hydrogen- and oxygen-based propellants as fuel. Why are hydrogen-fluorine fuels not used? It has a specific impulse of 390 seconds, higher than hydrogen-oxygen combustion (360 ...
30
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4answers
6k views

Why was this Saturn rocket elevated for launch?

This is an image of a Saturn on the launch pad on July 20th 1973 It appears to be resting on an elevated platform that raises it significantly off the ground. Why was this done? It seems like a lot ...
30
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3answers
4k views

Why do the exhaust flames from cryogenic stage engines appear to be separated from the nozzle?

Why do the exhaust flames from cryogenic stage engines appear to be separated from the nozzle?
30
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4answers
12k views

Effect of atmospheric drag on rocket launches and benefits of high altitude launch sites

What is the approximate influence of atmospheric drag on the cost of rocket launches? Is it beneficial to have launch sites located at higher altitudes? Cape Canaveral is at sea level, but I've ...
29
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5answers
15k views

Why does a rocket engine provide more thrust in a vacuum than in atmosphere?

According to NASA Each Space Shuttle Main Engine operates at a liquid oxygen/liquid hydrogen mixture ratio of 6 to 1 to produce a sea level thrust of 179,097 kilograms (375,000 pounds) and ...
28
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3answers
4k views

Did the Challenger SRBs fail due to design for reuse?

All that I know about the Challenger tragedy was that some o-rings failed in the reusable solid rocket boosters (SRBs) due to the low temperatures that day. I'm curious if such an accident would have ...
28
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6answers
5k views

Why did it take so long for methane to be used as a rocket propellant?

SpaceX have put methane on the map as a rocket fuel, but they weren't the first to consider its use. The first experiments in building a rocket engine that uses methane date back to 2007. Now methane ...
28
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4answers
3k views

What will be NASA's successor to the Saturn V rocket?

The Saturn V rockets were the "tallest, heaviest, and most powerful rocket ever brought to operational status and still holds the record for heaviest payload launched and heaviest payload capacity to ...
28
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1answer
2k views

Why do the Shuttle's external tanks appear to be rusted?

Wikipedia article states as STS-1 at liftoff. The External Tank was painted white for the first two Space Shuttle launches. From STS-3 on, it was left unpainted. I wonder why the ...
28
votes
1answer
2k views

Why do the Russians use these fence-like interstage fairings?

When we look at various Russian rockets we often see a metal structure looking like a kind of garden fence separating some stages. To my knowledge, only the R7 family (Vostok, Voshkod, Soyuz) and N1 ...
27
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3answers
8k views

What is the purpose of the black-and-white patterns on some rockets?

Some rockets have black-and-white patterns painted on them. For example, the Saturn V has them at the bottom of the upper stages and the SLS block 2 is supposed to have them below the payload. In ...
26
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4answers
4k views

Why aren't payloads their own fairings?

...or if they can, why so rarely? I mean: instead of placing a satellite of nondescript shape inside a fairing which is discarded somewhere above the atmosphere, build it in such a way that its ...
26
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2answers
5k views

Why did SpaceX retire Falcon 1?

Why did SpaceX retire Falcon 1? Wouldn't it have been more cost effective then Falcon 9 for lighter missions?
26
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1answer
4k views

Why are spaceship capsules frustum shaped?

Why do spaceships have a frustum (portion of a cone) shape like e.g. the pressure capsule of the SpaceX Dragon on the image below?     I think there is some engineering stuff behind ...
25
votes
3answers
7k views

Why doesn't the US use European rocket engines?

US Companies have been using Russian rocket engines for their rockets for a long time, even during sanctions. But as I was going through the European rocket launches, I felt European rocket engines ...
24
votes
1answer
1k views

For a 3 booster rocket, why do they start with igniting the starboard booster, followed by the center and port?

In today's launch of the Delta IV heavy, it was stated that the starboard booster rocket would be ignited first, followed by the port and centre boosters. I would have thought this would give some ...
24
votes
1answer
3k views

Do all launches include self-destruct mechanisms?

Do all launches involve self-destruct mechanisms? How do they usually work? Is it just the boosters that are required to self-destruct? In the case of the space shuttle, how about the external tank? ...
23
votes
5answers
8k views

What is the feasibility of a rocket hobbyist achieving a LEO orbit with a microsat?

Along with being a rocket hobbyist, I'm also an Amateur Radio Operator. I would like to determine the possibility of placing a "microsat" a miniature packet radio satellite, into a low earth orbit.
23
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2answers
7k views

Does launching a device into orbit change earth's orbit?

Does launching a space shuttle or rocket change the earth's orbit? After all, to get momentum in space you need to throw something out.
23
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3answers
61k views

What is meaning of T in rocket launch countdown?

In Rocket Launch countdowns I noticed That they count with respect to some parameter T as: T-10 seconds T-9 seconds . . . T-0 seconds Why not simply count as 10 9 8 . . 0 ? http://www.nasa.gov/...
23
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2answers
3k views

Saturn V Exhaust Plume

When the Saturn V launch vehicles reached high altitudes and speeds, the exhaust plume looks drastically different compared to how it did at launch (it is much larger, and has a cone about halfway ...
22
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3answers
3k views

Why do some rockets not ignite all their engines during liftoff? (GSLV MK3 LV)

As I understand it, a rocket should produce its maximum thrust on liftoff. As time progresses, the mass of the rocket will decrease, but since the engines produce the same thrust, the rocket will ...
22
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4answers
17k views

Is the SLS irrelevant if the Falcon Heavy launch is successful this year?

My take is that, like so many bad, and good, NASA ideas, the SLS will get the axe after spending billions on the NASA subcontractor(s). Regardless if the SLS comes to full life cycle, NASA will not ...
21
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4answers
4k views

Why does the Falcon 9 use RP-1/LOx and not LH2/LOx?

Why does SpaceX use RP-1 in the first and second stages of their rockets? In my view at least the second stage could use hydrogen as it currently is not being reused. I am aware that you have higher ...
21
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4answers
5k views

Why 31 engines for the BFR?

I understand the philosophy of using relatively many smaller engines so that a single engine failure has minimal impact on the mission (provided you can keep the shrapnel from shredding the others) ...
21
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2answers
3k views

Does SpaceX use any of Falcon-9's camera data for engineering or status information, or are they “just for PR”?

I've previously asked Roughly how many self-viewing cameras are present in a Falcon 9 LEO mission? asking if it's closer to a dozen or a hundred on a log scale, because I have a hunch there's probably ...
21
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3answers
2k views

Were decommissioned Cold War missiles repurposed for peaceful spaceflight?

Those formerly on either side of the Iron Curtain can now admit that the Cold War had its plusses and minuses. The key minus, of course, is that the United States and the Soviet Union constructed ...
21
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3answers
9k views

What's the largest single object payload ever lifted into space?

I am aware that the Saturn V is the largest rocket ever built and was capable of lifting more weight into space than anything that exists today. Modern rockets often carry several satellites up at ...
21
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2answers
3k views

Am I allowed to send a rocket to LEO?

I am not affiliated with any space agency. I do not have the resources to do so, but am I allowed to send a rocket to LEO without talking to any federal agency? Obviously that could be a danger to ...
20
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3answers
6k views

Why are the Falcon Heavy boosters stacked in a row instead of a triangle?

I wonder if triangle stack would be a better design to handle thrust and stability of the flight. Photo source (public domain).
20
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5answers
33k views

Is it possible to reach space using home-made rocket?

The first stage would be a high altitude balloon, which could reach 30km. Then start a rocket-candy from that high. Without cargo, is it possible to reach the edge of space (Kármán line - 100km), or ...
20
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2answers
6k views

Can a rocket be launched while it rains?

All videos of rocket launches I ever saw were performed in clear weather conditions. I also read many reports about launches which were delayed because of bad weather conditions. What are the ...
20
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3answers
7k views

Why are rocket launches so sensitive to weather?

I've been following the upcoming launch of the Antares rocket to resupply the ISS (scheduled for today, July 13, 2014). This launch was originally scheduled for May, and has been rescheduled multiple ...
20
votes
1answer
5k views

Why is the SABRE engine curved?

Why is the Reaction Engines Limited SABRE (Synergistic Air-Breathing Rocket Engine) curved along it's length?     Illustration of the SABRE engine with the pre-cooler heat ...