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Questions tagged [mass]

Questions regarding the mass of spacecraft or other objects

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Falcon 9: how much fuel is left on a booster after stage separation?

If the booster attempts either land or sea landing, how much fuel (RP-1 and LOX) is left in its tanks right after stage separation? Recently, I have heard numbers as high as 30% of its total tank ...
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Are there any advantages to being a smaller spacecraft for reentry?

Could a ship drop its cargo or shed weight before reentry to lessen the strain on the ship during reentry? Would a ship breaking down to smaller parts before reentry have any advantages over being one ...
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2answers
456 views

What is a typical satellite solar panel mass?

Does anyone know a reliable source to find the mass of solar panels on satellites (in particular GEO satellites)? I know they will vary but I am struggling to even find one data point let alone a ...
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What is the largest and/or heaviest object that could be sent to space?

What is the largest and/or heaviest object that could be sent to space? I know the space station is sent in pieces but I am looking with one launch.
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307 views

How precisely do we know mass of the ISS?

Everyone knows that in space, every gram counts. Knowing how much mass an orbital object has is necessary for precise motion calculations. So how precisely do we know the mass of ISS? I'm sure we can ...
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1answer
521 views

Does the size of a satellite have an effect on orbit?

I understand that lighter satellites orbits decay faster. There is 2 satellites that weigh the same but 1 is huge and the other tiny in comparison. Would the size of the satellite make a difference on ...
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2answers
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What size payloads could we feasibly launch from the moon with a mass driver?

I've been wondering how large a payload could be launched & if it's viable to launch those payloads directly to the earth for splashdown & collection. Obviously the payload would need to be ...
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1answer
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Problem in finding Propellant Mass using Rocket equation where total mass includes components dependant on Propellant Mass

Formulation - $$e^{\Delta v/v_{exhaust}} - 1=mass_{fuel}/mass_{structure}$$ $\text{let } k=e^{\Delta v/v_{exhaust}} - 1 $ $$\implies mass_{fuel}= k \times mass_{structure} $$ According to SMAD (...
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How much will Europa Clipper weigh?

I realize that NASA will have to change Europa Clipper's loadout based on whether they are launching on the SLS 1b or the Atlas 5 backup, but does anyone know what those two mission masses will be, ...
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2answers
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Is centre of mass a factor in space without gravity?

Quick disclaimer; I'm not that well informed on many of the mechanics on space in general so sorry if this question is rather easy/basic. Is the center of mass in a object a factor in space when ...
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1answer
307 views

How can I obtain the necessary thrusts / mass flow rates to achieve a given burnout velocity for an optimally staged rocket?

I understand how to use lagrange multipliers to obtain the optimal stage masses given the payload mass, the burnout velocity, the structural ratios of each stage and the specific impulses of each ...
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3answers
349 views

Could daily variations of weight on Earth really be 0.003%?

I've been reading about accelerometers. On earth, in a lecture demonstration, in a table-top experiment, they will generate a signal equal to the sum of the acceleration you'd like to measure plus the ...
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1answer
769 views

Where to find the best values for standard gravitational parameters of solar system bodies?

Where can I find the best values to use for standard gravitational parameters of solar system bodies for numerical simulation experiments? Here are two sets I've put together. The first set is from ...
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2answers
592 views

What happens to materials which burn up during reentry?

The common conception of satellite reentry is that they just burn up and are "gone". But the total mass must still be somewhere, right? What forms does it all end up as, and where?
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What determines the orbital speed around a massless Lagrangian point?

What value of M should I use to calculate the speed of a satellite orbiting a Lagrangian point where there exists no mass?
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1answer
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Why vent $CO_2$ and $H_2$ waste products to space on ISS?

In this answer, it's mentioned that waste $CO_2$ and $H_2$ from the Environmental Control and Life Support Systems (ECLSS) are vented into space from ISS. Are there no other uses for this material ...
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2answers
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Common usage of “dry-mass”

Usually, I would consider the dry-mass the mass of a vehicle without any consumables, passengers, or cargo. This NASA article however describes the Apollo 11 Eagle as: The lunar module was a two-...
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1answer
643 views

What is the minimum rocket mass that can achieve GEO

A tiny model rocket can't get up very high. Massive rockets can make it to GEO. There must be some theoretical mass threshold where the rocket is "big enough" to make it to GEO - what is that mass? ...
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4answers
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What limits miniaturization of space probes?

Another run of kerbal got me thinking about what, in reality, makes up the limit for small, but still useful space probes. The rationale should be obvious: The rocket equation does not hurt that ...
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2answers
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What savings allowed James Webb telescope to be lighter than Hubble?

Wikipedia states: The telescope has an expected mass about half of Hubble Space Telescope's, but its primary mirror (a 6.5 meter diameter gold-coated beryllium reflector) will have a collecting ...
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1answer
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Why is Curiosity so light compared to Opportunity?

Look at that: ...and now tell me how comes Opportunity weighs 530kg and Curiosity 900kg. It looks, like by volume, Curiosity is good 4x larger, if not more. Plus it contains heavyweight RTGs, its ...
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550 views

Data for Moons in the Solar System with Masses

I'm looking for a simple machine-readable table with basic parameters for all the known moons of the planets in the solar system. Stumbling around the internet, I can find plenty of sources like this ...
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Did the Mars rovers actually confirm the gravity of Mars?

For years the theoretical calculated gravity of Mars has proliferated science texts and Internet documentation - but did the rover actually do a test to confirm the theoretical gravity is truly equal ...
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366 views

Why is the Dragon small compared with the Falcon 9 LEO payload

According to wikipedia, the Falcon 9 1.0 had ca. 10t payload capacity to LEO. The Dragon has a 3.3t payload capacity to the ISS with a dry mass of 4.2t that leaves 2.5t unused lift capacity. Is this ...
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183 views

Is buoyancy of rockets a factor taken into account?

A twist on the Archimedes law. Any object in Earth's atmosphere should weigh less than in vacuum, by amount of mass of air it displaces. At 1.2 kg/m³ of air at sea level, that is a bit of a difference,...
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1answer
2k views

How did the Space Shuttle maintain thrust/weight balance

As a seasoned KSP player, I am aware of how important it is during ascent to have center of thrust and center of mass perfectly aligned. If you don't, your rocket will deviate from its course and ...
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1answer
436 views

Is there a non brute-force algorithm for finding the combination of rocket components to maximize delta-v for a certain launch mass?

Let's say we want to build a rocket that has the maximum amount of delta-v in deep space, but its launch mass has to be less than some number. We have a finite list of rocket components that can be ...
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342 views

Why have space stations become less volume-efficient despite technological progression?

If you compare the pressurized volume of all the space stations launched to their mass, their volume-efficiency (in this context volume divided by mass) seem to decrease over time. In chronological ...
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What is the total mass of everything launched that are still in space?

Inspired by this question, total mass ever launched to orbit (this is a different question, as many of the things launched have decayed by now.) How much of it is still up there? Out of that again, ...
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3answers
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How does the roll maneuver allow more mass to be lifted into orbit?

I read recently that the roll maneuver that rockets perform shortly after clearing the tower to become tilted serves a few purposes (Shuttle and Apollo Saturn V alike). I understand most of these ...
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1answer
403 views

wouldn't adding mass to Mars be problematic for its rotation as well as other planets? [closed]

Was reading Which planet or moon would be most feasible to terraform? and specially https://space.stackexchange.com/a/206/12379 . I am not really good at science or maths so please excuse below and ...
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Are there interstellar Lagrange points?

Is there for example some L1 like libration point where the Hill spheres of the Sun and of the Alpha+Beta Centauri meet? And are Lagrange points between stars inside of a binary system, like Alpha and ...
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4answers
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Why are rocket mass on the launch pad and payload mass to LEO not strongly correlated?

What explains the relation between how much a launcher weights on the launch pad, and how much mass it can lift to orbit? I had expected that more payload requires more fuel to be launched and that a ...
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1answer
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Total Mass of the ISS Solar Array

This document does a pretty decent job of detailing the ISS solar array. There's one part, however, that is sort of ambiguous and critical to an analysis I'm performing, and so I thought I might ask ...
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Why can't we launch from space?

So this may be a stupid question but I was wondering why we couldn't launch from space. I know that most of the fuel that we spend is for escaping Earth gravity. Yet, if we have already done this with ...
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1answer
462 views

Considering the relativity of time, how is time experienced in deep space? [closed]

To be more specific, if the relativity of time is governed by the mass and gravity of objects (I.E the satellites orbiting earth experience minor time dilation compared to us on the ground), how is it ...
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1answer
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How much extraneous mass did each of the Apollo missions carry?

By "extraneous mass" I am referring to any mass which had not as its primary purpose onboard or attached to the launch vehicle to contribute to the technical or scientific goals of each mission. For ...
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What are the masses of the docking / berthing mechanisms used by the ISS?

I have been unable to find any information on the masses of the docking / berthing mechanisms used by the ISS. What are the masses of the APAS-95, Active / Passive Common Berthing Mechanism, and ...
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1answer
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What was known about 67P/C-G's mass before the arrival of Rosetta?

The determination of the mass of a celestial object is usually between hard and impossible unless one can observe something that orbits it. In the case of comet 67P/Churyumov–Gerasimenko, one of ...
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What fraction of a liquid rocket launching from Mars to return to Earth would be fuel?

I've tried to get my head around this and have decided that, for the moment, I don't want to learn to solve logarithmic equations. Too much else going on. I was reading Mars Direct and got the ...
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1answer
275 views

Does a persons weight effect their potential selection to be an astronaut?

Every extra bit of weight cost extra to send to orbit. Presumably it also impacts the possible payload. Assuming a generally healthy build, and otherwise physically able and fit person. In ...
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611 views

Proportions of a reentering spacecraft as compared to fuel mass

Call this a thought experiment. Spacecraft to Earth orbit and beyond are traditionally launched by means of one or more rocket engines. The fundamental principle is that a rocket moves by expelling ...
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How do you weigh things in a micro-gravity environment?

Obviously a balance scale is not going to add value to the task in free-fall. Weight in space is more accurately described as mass, but the need to define it still exists. Regardless of if you're ...