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Questions tagged [launch]

Questions regarding the takeoff or the liftoff phase of the flight of a rocket and the set of activities required for preparation of the launch vehicle leading to it.

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3answers
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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 ...
55
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5answers
6k 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 ...
27
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6answers
3k views

What technological hurdles prevent the development of a space gun?

Ever since Jules Verne wrote "From the Earth to the Moon" space guns have long been proposed as a method of launching objects into space. And for non-human, non-fragile payloads they make sense as the ...
28
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1answer
56k views

What is the current cost-per-pound to send something into LEO?

As a student of economics and finance I would love to learn more about the cost structures of sending a payload into orbit. More specifically - What is the cost-per-pound to send something into LEO ...
41
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11answers
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Could it be possible to launch a rocket from a balloon?

There are several (commercial) organisations looking into alternative means to launch space-bound rockets. One commonly proposed method is to use a large airplane as the launch platform. This method ...
36
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5answers
11k views

Why aren't all satellite-carrying rockets launched from airplanes?

There are several significant advantages to air launching a satellite-carrying rocket: save fuel/propellant as a horizontal take-off is more energy efficient fully mobile platform allowing the launch ...
42
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2answers
35k views

What is the purpose of the jets of water often under rocket engines during launch?

I have watched several STS launches, and noticed that there were always huge jets of water that would begin right before the rocket engines lit. They were right under the rocket, mounted to the pad. ...
16
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5answers
17k views

Can magnets be used to launch spacecraft?

I assume there is some reason we don't use magnets to launch off Earth. Are they not strong enough? Isn't magnetic force technically stronger than gravity?? Would either of these work: A tube tunnel ...
16
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2answers
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Launch Accelerations: Values, history

This topic: What G-forces do different launchers cause? indicates that current satellite launchers are limiting peak acceleration to about 4g. I'm pretty sure the STS (Shuttle) did the same. My ...
4
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2answers
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How does one dogleg from Florida to a sun-synchronous orbit?

From NASA Spaceflight's article SpaceX Falcon 9 launches first NRO mission with NROL-76: The NROL-76 launch was not to be targeting a sun-synchronous orbit, typically used by the NRO’s optical ...
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2answers
594 views

What regulations, agreements, or other forces can help mitigate “PrankSats”? [closed]

comment: I've used a somewhat innocuous abstraction of 'pranks in space' below, but there's no end to the trouble that could be caused and the increasing ease with which a state (nation or otherwise) ...
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4answers
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What is the purpose of having a countdown during a rocket launch?

Every rocket launch has a countdown. But what purpose does it serve?
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4answers
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What are the towers around the SpaceX launch pad used for?

I noticed four(?) towers around the SpaceX launch pad during yesterday's aborted launch Image credit NBC News What are the towers used for? Tracking? Radio communications?
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3answers
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How long does Max-Q last?

When watching rocket launches, the commentary or status reports often mention that the vehicle is "passing through Max-Q" - how long does the "passing" take? Is the event instantaneous or is there ...
11
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3answers
4k views

Will the Tesla Roadster return any telemetry?

Is there any equipment fitted to the Tesla Roadster to send signals back to Earth, even for a short time after launch?
16
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1answer
730 views

Cause of apparent plume deflection on SES-10?

While watching the SES-10 flight, starting a little after T+1:30, I noticed that the direction of the first-stage exhaust plume started to diverge from the alignment of the rocket body. The ...
9
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3answers
2k views

On a Super-Earth 1.5x the volume and mass of Earth, would our rocket technology allow us to reach orbit? [duplicate]

To try and make parameters clear, can we say we are talking about 50% 'more Earth'? As in, Earth, but 1.5 times as big and heavy? And let us include the atmosphere. If there is 50% more of it by ...
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10answers
12k views

Why don't we use catapults to get to space?

Stupid question obviously. But did you ever had an idea which sounded so brilliant, but you know it is totally stupid? So, lets hear my idea: Do you know how we launch jet fighters from navy ships? ...
28
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2answers
3k views

SpaceX CRS-5 Launch: What is the footage that appears to contain bubbles?

I'm currently watching the live stream of the CRS-5 launch. They've been cycling through several different camera angles including one which looks a lot like bubbles in water, or perhaps blobs of ...
29
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5answers
9k views

Why didn't NASA use the shuttle to make a profit?

My understanding is the shuttle was designed as cost-effective workhorse, a space-van to ferry cargo up to the ISS, conduct zero-G experiments and put satellites into orbit. So why didn't NASA take ...
31
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3answers
13k 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 ...
35
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2answers
45k 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?
5
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0answers
175 views

Was it another Fishing Tournament?

@KimHolder's thorough answer to the question What are the consequences for a person who violates a launch exclusion zone? mentioned a fishing tournament. @PearsonArtPhoto's comment about scheduling ...
18
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4answers
5k views

What is the largest hurdle of the mission to Mars?

I was shocked when I recently found out just how long it takes to get to Mars. I've been conducting a very informal survey amongst peers of how just how long people think it takes us to travel to Mars....
28
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4answers
4k views

Do any launches bypass LEO?

If sending a payload to GEO (geosynchronous orbit) or any other high orbit, you could start off launching to LEO (low Earth orbit), and then use a Hohmann transfer to raise the height of the orbit. I ...
25
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1answer
18k views

What are the droplets/particles falling off rockets at launch?

In this picture from the AsiaSat 6 launch by Falcon 9 on 8th September 2014, the part of the rocket between the fairing and the engine appears to be surrounded by dust, water droplets or debris: And ...
22
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6answers
13k views

Could a Human reach escape velocity by jumping from the surface of Ceres (a dwarf planet)?

According to this answer the surface gravity of Ceres is estimated to be only $0.27 m/s^2$. With a rotation period of 9 hours. The gravity seems light enough to overcome by leg muscle alone, and if ...
14
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4answers
16k views

How close can I get to a rocket launch and not get killed?

There was a question regarding the closest distance regular people are allowed to be near a rocket. At that distance (Baikonur I, 1.1 miles), even if a rocket explodes, there is a small chance someone ...
39
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3answers
8k views

How is a rocket stabilized during the initial, slow speed, portion of launch?

Let's say we're at T+0, just as the rocket starts to move, what keeps it upright as it clears the tower and gains speed?
18
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3answers
3k views

Why is Falcon 9's shape so tall and skinny?

Compared to most rockets I know of, Space X's Falcon 9 seems unusually tall and skinny. The v1.1 version is nearly 70m tall, yet only 3.6m thick. For comparison, Atlas V is 58m tall and 3.8m thick, ...
15
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2answers
1k views

Why would a mission to Sun-Earth L1 have an instantaneous launch window?

I was watching the webcast for Falcon 9 Flight 15 (launching DSCOVR) when they scrubbed their first launch attempt due to some issues during the terminal countdown. Before the scrub, the narrator ...
7
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2answers
2k views

What is the problem with aborting a Space Shuttle launch?

In the question Why didn't the Space Shuttle have a launch escape system? there was discussion in the commentary about why the Space Shuttle could not safely abort through much of its envelope. ...
7
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6answers
2k views

What benefits can be gained from launching below ground?

ICBMs are commonly launched from below ground. How much fuel could be saved if a missile is launched below ground instead of above? If the tube was deeper with modified launch by a separate chemical ...
3
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1answer
11k views

How far away can one see a NASA rocket launch?

I live in a Maryland suburb of Washington, D.C., and the weatherman thought we'd be able to see a rocket launched from Wallops Island (alas, it blew up instead) which by car is 166 miles away. ...
13
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4answers
2k views

What is a “space elevator”?

I've seen an hypothetical "Space elevator" referenced in various media the last couple of years. Is this something thats really planned in the making, or just a hypothetical scenario? How will a space ...
12
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1answer
1k views

What is it that SpaceX is editing out of their videos after posting them on YouTube?

Here are two cases where links to a specific time code in SpaceX YouTube videos stop showing the intended moment because apparently SpaceX has gone in within hours or perhaps a day and shortened the ...
12
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1answer
1k views

Are there international regulations for launching objects into space?

In the United States access to space is restricted by the FCC / FAA, which licenses private, commercial, and government entities for potential launches into space. Is there any international ...
11
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3answers
2k views

What would make a rocket sled launch feasible?

Wikipedia introduces the idea of a Rocket Sled Launch (also catapult launch, ramped launch, etc) as follows: With this concept the launch vehicle is supported by an eastward pointing rail or maglev ...
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2answers
904 views

Which STS mission raised the normal engine throttle above 100%, and what change to the SSME made that possible?

As indirectly stated in an answer to How long does Max-Q last?, during later Space Shuttle launches the main engines were operating at above 100% of their nominal maximum thrust. Specifically from ...
2
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1answer
603 views

Why would sub-cooled LOX tanks need to “topped-off” until the last minute or so?

Here is my understanding, let me know if I've got it right or wrong: Until recently, most cryogenic propellants were at or close to their boiling points. Each unit of heat leaking into the tank would ...
56
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3answers
49k views

What happens to the Falcon 9 second stage after payload separation?

In a Falcon 9 launch, the second stage looks like it achieves orbit along with the payload. But is that impression accurate? Does SpaceX need to do anything to deorbit the stage? I can see a few ...
26
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7answers
61k views

Does the space shuttle fly straight “up” when leaving Earth?

I was watching space shuttle launch recently, and at 2:53 you can see the space shuttle from an angle, even though it's high above the earth and you should see only the bottom. Does the space shuttle ...
31
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6answers
6k views

Why is there a “coasting” phase in some space launches?

During the PSLV (India's Polar Satellite Launch Vehicle) C24 launch on 4 April 2014, once stage 3 (PS3) had burned out, it wasn't immediately jettisoned, but instead there was a coasting phase for ...
17
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3answers
12k views

How much of an advantage do equator-proximal launch sites provide?

Comparing ESA's Kourou (5° off) with NASA's Cape Canaveral (28°) and JAXA's Tanegashima (30°) launch sites, how advantageous is proximity to the equator? Considering the fact that the ESA and all of ...
36
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3answers
4k views

Why was AMOS-6 mounted on the rocket for a test fire?

I understand that the static test is a general test of pre-launch procedures, but risking a multi-million dollar payload for a test seems remarkable. Couldn't they use a mass simulator or something? ...
17
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1answer
1k views

What was the distant bright light in the SpaceX webcast of Orbcomm OG2 deployment?

As I was watching the SpaceX launch today on YouTube, I have noticed a bright distant light as the satellites were being deployed. What was that light? Also, after each deployment there was something ...
14
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1answer
2k views

Why did the recent Sirius FM6 launch use such a high inclination?

Earlier today a Proton-M rocket took off, carrying a Sirius FM6 satellite radio payload destined for geosynchronous orbit. Nothing super exciting, Briz-M upper stage for transfer burns and then the ...
27
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3answers
9k 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 ...
20
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3answers
6k views

Is there any advantage in launching spacecraft from a high latitude, or why was Plesetsk built so far north?

For launching satellites or other spacecraft, there is a significant advantage in being close to the equator: angular momentum helps in gaining initial speed and one can launch into any inclination. ...
15
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1answer
6k views

Why did Apollo use roll and pitch maneuvers similar to Space Shuttle to establish ascent trajectory?

When the Space Shuttle launched, it would perform a roll and then pitch to establish its ascent trajectory. There is fairly straightforward rationale for this. The vehicle's aerodynamic shape, the ...