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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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How do launches avoid leap seconds? Why?

A short comment in the BBC Crowd Science audio program Does Time really Exist?'s discussion of the slow divergence between UTC and TAI (IAT) (coordinated time and international atomic time) says that ...
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2answers
800 views

How great is the stress on a rocket at max-q [closed]

How much more stress does a rocket experience during max-q compared to other parts of the flight (such as when it is at rest on the pad)? Use data for any 'cylindrical' rocket if a specific example ...
2
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1answer
226 views

Why would there be a launch window for a Geosynchronous orbit? [duplicate]

The question is pretty much stated in the title. Is there anything other than "human caused" reasons for this (such as clearing airspaces, etc.)? I'm only looking for possible natural reasons (other ...
2
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1answer
472 views

Ejection charges on Dnepr Rocket tube?

The Dnepr rocket was initially developed for use as a ballistic missile. Therefore it was developed with an explosive charge that fired the rocket out of the ground and into the air, followed by the ...
2
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0answers
139 views

For a cubesat mission piggybacking on a Red Dragon, what are the tradeoffs for launch early and late in the launch window?

SpaceX will be launching two Red Dragons in 2020, one at the beginning of the launch window (July) and one at the end (September). For a CubeSat mission that would have to piggyback on one of the two ...
3
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1answer
136 views

What type of work goes into refurbishing a launch pad?

I read that launch pads need to be refurbished after every launch. What stuff on the pad takes damage? What is stopping them from covering the "stuff" in some sort of flame-retardant, explosion-proof ...
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1answer
1k views

Relation between launch window and RAAN and Argument Of Perigee

Dear Friends, Does any dependency exists for achieving particular combination of RAAN ( Right Ascension Of Ascending Node) and argument of perigee with respect to particular launch date ...
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0answers
174 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 ...
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0answers
158 views

Does a safety team get fined if a rocket launch fails due to the safety of the rocket?

I was writing a story and I wanted to write about this topic but I could not find a straight answer from any website. Please help
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 ...
1
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1answer
154 views

Is there a significant difference between launching a polar orbit mission south from New Zealand versus launching it north?

The Channel News Asia article New Zealand launches into space race with 3D-printed rocket says: Ships and planes need re-routing every time a rocket is launched, which limits opportunities in ...
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1answer
447 views

Why is Rocket Lab's New Zealand launch site good for polar orbits?

The Channel News Asia article New Zealand launches into space race with 3D-printed rocket says: Ships and planes need re-routing every time a rocket is launched, which limits opportunities in ...
7
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1answer
483 views

Green fire in Inmarsat-5 Launch [duplicate]

The Inmarsat-5 from SpaceX launched earlier today. I was watching the broadcast and noticed a brief green flame during ignition. What caused this?
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0answers
139 views

When have secondary payloads damaged the primary payload of a launcher?

Primary payload customers have traditionally been cautious when allowing secondary payloads on the same launcher. For example, a secondary payload is not trusted to have its own chemical propulsion ...
3
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1answer
157 views

What “regulatory purposes” would limit a launch test of a new vehicle to 50,000 feet?

The Art Technica article Vector has completed the first successful flight test of its new micro rocket says: Vector Space Systems successfully launched a full-scale model of its Vector-R rocket on ...
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0answers
84 views

What about recycling the helium used for sub-cooling the LOX in the tank of a rocket before launch?

Helium is a rare and expensive noble gas. When it is loaded into a rocket to be used after launch, it is not possible to recycle it. But the helium used for sub-cooling the LOX before launch (see ...
2
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1answer
544 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 ...
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2answers
1k views

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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3answers
3k views

Why does a spacecraft have angular velocity relative to Earth?

I am reading sci-history about first steps into space. Before landing cosmonauts had to choose at which loop around Earth they would start landing procedures. Why does spacecraft have angular ...
3
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1answer
267 views

Why Did Apollo Smoke Twist When Taking Off?

I've been looking at some references of rockets taking off. I came across the Apollo 14 Saturn V launch and noticed that when the rocket was taking off the smoke coming from around the rocket and from ...
8
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1answer
284 views

Puzzler: What acceleration are these astronauts experiencing?

From only the video footage within the capsule, please estimate the rocket's acceleration (gee's). http://www.bbc.com/news/science-environment-39658947 Show all work and assumptions. There is a ...
15
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3answers
1k 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 ...
6
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1answer
351 views

Upper stage structural loads on ascent?

In another question, this came up: For example, if a Falcon 9 launches 20 tons of fuel to dock in LEO, how can the same upper stage be used to launch 40 tons of fuel to the same orbit? Doesn't it ...
6
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1answer
594 views

What computer programs does ITAR say I can or can not write, or share, or use in the US?

After reading this answer by someone knowledgeable in the field, I realized that I still don't understand even a little bit what International Traffic in Arms Regulations (ITAR) (and its cousins) does ...
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0answers
63 views

Why do rockets sometimes climbs down before reaching orbital velocity? [duplicate]

Looking at this Ariane 5 launch, I notice that: the speed continously increase (as I expected) the altitude first increase as I expected, then decrease (I was not expecting that) and then increase ...
9
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1answer
699 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, ...
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1answer
2k views

Why does the CRS-8 Falcon 9 rocket appear to be swaying before launch?

I just saw the video from the YouTube channel SpaceX Edits titled SpaceX B1021: The First Rocket to Fly Twice (a supercut of highlights mentioned in the Pod Bay, and noticed the Falcon 9 for the CRS-8 ...
16
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1answer
710 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 ...
6
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5answers
23k views

How far south can one see a rocket launch from Cape Canaveral, Florida?

I'll be in Miami this Thursday 30th of March and there is a SpaceX Falcon 9 rocket launch from LC-39A, Kennedy Space Center, Florida (if it's not delayed). I won't be able to drive north to be on ...
6
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1answer
908 views

How to determine $\Delta v$ loss due to gravitational pull from earth

How do I find the delta-v loss of a rocket while ascending to its apogee? Specification of Atlas V 541 rocket: Specification for Atlas V first stage: Dry Mass: 21054 kg Fuel and Oxidizer(RP1/LOX) ...
14
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1answer
485 views

How often are space launches substantially delayed by protests physically at the launch site?

Update: Following a one month loss of launch capability, from Spaceflight Now, April 25, 2017; Operations resume at European-run launch base in French Guiana: Protest leaders demanded more 3 ...
10
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1answer
245 views

How much water to the east is needed?

The ESA has its launchpad in French Guiana. It's not only close to the equator but also has a lot of water to the east, meaning that boosters can fall down without hurting people (probably). But in ...
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2answers
83 views

Websites about past and future missions

What are some good space related websites (or other resources) that have information about past and future missions? I'm looking for data such as mission launch date, type of rocket, launch site, ...
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4answers
7k 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 ...
7
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2answers
810 views

Why is OA-7 launching atop an Atlas V?

After replacing the old refurbished NK33 engines with newer RD-181 engines on Antares, and the successful OA-5 launch with Cygnus to the ISS, why is the next launch of Cygnus occurring on an Atlas V? ...
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0answers
94 views

What is the maximal distance to see a rocket's flare in the sky? [duplicate]

We get onboard a cruise ship 5 to 6 hours prior to the launch, in direction of Nassau, Bahamas. Cruising at about 25 km/hr, we should be about 150 km away from the pad.Do you think that we still have ...
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7answers
546 views

Vacuum launch, essentially free after system built

Outside Earths atmosphere is the vacuum of space and its immense power. If a cylindrical tube of sufficient strength and size were built tall enough to reach the edge of atmosphere would it not be ...
4
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2answers
251 views

How to transport gigawatt-level power across a 100km distance?

I'm investigating the idea of transporting gigawatts of electrical power to the first stage booster of an electrical rocket. The first stage booster, like Falcon 9's recoverable first stage, stages ...
7
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1answer
380 views

Preflighting TVC actuators on Falcon 9

It is my understanding that the Falcon 9 thrust vector control (TVC) actuators use RP-1 as hydraulic fluid and use the fuel turbopump energy to drive the hydraulic pump for the TVC. How do you do a ...
16
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3answers
4k views

Were the Space Shuttle's Main Engines ever off while the Solid Rocket Boosters were firing?

I always though the Space Shuttle needed a combination of its solid rocket boosters and its main engines to remain stable while launching. The following diagram found on Wikipedia seems to agree: ...
0
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1answer
251 views

Could maglev + scramjet be used to launch rockets to space? [duplicate]

Scramjet technology allows for propulsion once Mach4 is reached, without needing oxidizer thus reducing the weight up to 80% (as read in https://medium.com/@rsn/spacex-falcon-9-vs-isros-reusable-...
4
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0answers
284 views

Launch windows for on-orbit rendezvous

Suppose you've got a spacecraft in an orbit similar to that of ISS (let's say 51.6 degrees, but about 19 km lower). Suppose also you want to launch a second spacecraft to rendezvous with the first, ...
3
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5answers
848 views

Are there any downsides to high TWR rockets?

High Thrust to Weight Ratio (TWR) rockets means get into fairly quickly and constantly experiencing G-Force, are there any downsides to high TWR rockets other than engineering? Seems like there are no ...
9
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5answers
6k views

Cubesat Launch Costs

What are tentative launch costs for 1U/3U cubesat on popular launchers? I checked up ISRO, SpaceX and others. Only RocketLab provides exact cost for cubesat as a piggy-back launch: \$77k / \$240k for ...
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2answers
2k views

What are the two bright objects separating from the Falcon 9?

On the recent Iridium 1 launch the separation of the first and second stages can be seen at T+3:50. In the following screenshot we see the second stage burning at the lower left of the frame and the ...
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1answer
648 views

Odor of a rocket launch?

Thinking of the primary propellants used for typical rocket launches (such as Hydrogen, RP-1, solid fuel), what are the odors of the exhaust and burned fuel components? I'd think that the Hydrogen ...
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1answer
730 views

How large a percentage of its fuel did the Space Shuttle use to get to orbit?

What percent of the total available fuel onboard the space shuttle, external tank, and rocket boosters was required to launch and get the space shuttle into orbit? Or phrased another way, what percent ...
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1answer
229 views

Can a laser be used to clear the launch path of a rocket?

Military grade lasers shooting down incoming missiles have been in the news since Ronald Reagan was the US president. The problems, as I recall are mostly about diffusion in atmosphere. The Kessler ...
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3answers
2k views

Is getting IN or OUT of orbit easier for the Space Shuttle? [closed]

Here is a brief dramatic of the Space Shuttle launch and reentry: Launch : You get on this plane like thing that is strapped to an orange fuel tank that looks more like a huge bomb. The fuel tank is ...
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3answers
805 views

How far in advance are launch dates set?

We are going to visit Florida in early-mid February and were wondering if we could watch a launch. The schedule, however, does not seem to include February yet. For the purposes of planning our trip -...