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Questions tagged [mass]

Questions regarding the mass of spacecraft or other objects

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13
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2answers
2k views

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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3answers
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What is the "mass" of a Lagrange point?

Of the five Lagrange points, L4 and L5, as stable points, can be orbited by asteroids, satellites, and any other useful or interesting object. Assuming two-body motion however, calculating orbits with ...
2
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1answer
137 views

Calculating total burn time for a rocket under constant acceleration with two propellant consumption rates

I tried posting this question on the Physics side of StackExchange but didn't get any response after a week, presumably because it was lost within the broadness of physics in general, so I'm hoping ...
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0answers
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Is there an estimate for the average mass of all meteoroids and asteroids hitting Earth's atmosphere in one year?

I wonder how much mass is entering Earth's atmosphere every year in the form of meteoroids and asteroids. This excludes micro-meteoroids, dust particles, molecules etc. Quick search result talks only ...
5
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1answer
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How long would it take for air to completely leak from a spacecraft?

If a spacecraft of volume V was leaking air of density rho as a mass flow rate of m-dot can you calculate the time for all the air to leak out using (rho x V)/m-dot? rho would decrease and m-dot ...
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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 ...
2
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2answers
272 views

What is inside Perseverance? Is the only scientific payload the bunch of instruments hanging from the arm?

Perseverance weighs about one ton, it is as big as a car. But what is inside the vehicle that weighs so much? Is the payload only the instruments hanging from the arm? Is all the remaining hardware (...
5
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1answer
300 views

How much mass does a gimbal mechanism add to a rocket?

After reading the question Did any rockets use differential throttling instead of gimbal? I wonder what the additional mass of a gimbal system is. How would the mass of a launch vehicle change if the ...
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How much of a deep space spacecraft's structural mass is useless dead weight after launch? Any plans to shed it in the future?

After seeing this in Security SE Magnetic core memory isn't quite extinct yet. The two Voyager spacecraft used it and are still functional. Core was/is certainly non-volatile. I did some ...
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1answer
134 views

What if we have a DC nozzle instead of a CD nozzle?

My understanding is that the exhaust gas gains velocity as its heat converts to kinetic energy, regardless of the geometry of the nozzle, and the reason we have a convergent-divergent (CD) nozzle is ...
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5answers
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Does trajectory of an object orbiting a planet depend on the object's mass? (With hypothetical Apollo example)

For example (hypothetically), if an Apollo crew of one of the lunar missions went on EVA just after Trans Earth Injection burn and carefully released a small bolt, or a plastic package from their food,...
2
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1answer
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IMLEO orbit height

Initial Mass in Low Earth Orbit is a well defined cost metric for space missions [1]. However, this is somewhat subjective since it depends on the orbit height. My guess is that there is a ...
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0answers
91 views

mass of the decks in the crewed SpaceX Starship [closed]

I want to work out the approximate mass of a Starship (crewed version) deck. We can assume an internal diameter of 8 meters with a 1.5 meter diameter central support tube. The loading is uncertain but ...
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76 views

Is Earth's Moon gaining or losing mass?

The Earth gains mass from dust/meteors (and a tiny, tiny bit to increasing temperatures/energy), but loses mass from hydrogen/helium escaping and nuclear reactions. It's estimated to have a net loss ...
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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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0answers
36 views

How much did each MarCO 6U cubesat weigh?

Yes the answer is zero now because they are weightless, but I used past tense. In any event, let's try to find a good, reliable source for each spacecraft's mass and whether that number is dry or ...
5
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1answer
218 views

Why are all possibly habitable exoplanets higher mass than Earth?

I have been writing a scifi book in which I wanted to include real stars and planets as locations. It was simple enough to find a chart on Wikipedia that lists possibly habitable exoplanets, but I ...
5
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2answers
353 views

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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3answers
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How close would the Tesla Roadster with Starman have to get to Earth in order to become attracted and fall on Earth?

In 2091 the Tesla Roadster is said to maybe get closer to Earth than the Moon is. At Starman's current speed, would its location in 2091 be sufficient for the Earth to re-attract the Starman to let it ...
6
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1answer
504 views

What is the thickness of a rocket nozzle?

For a university project, I'm working on optimisation of a Falcon-9-like launch vehicle, and one element of that is varying expansion ratios of the engines. This will impact on the engine mass, but to ...
2
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1answer
167 views

Is "liftoff mass" = "ignition mass"?

The answer to How much propellant is used up until liftoff? makes me wonder whether the terms "ignition mass" and "liftoff mass" have widely accepted precise meanings. Does anybody have an ...
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ISS Mass breakdown [duplicate]

I'm looking for some solid numbers that break down the mass of the ISS into functional categories (with the goal of making a neat pie chart). Such categories might include the mass of... Docked ...
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4answers
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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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2answers
235 views

Acceleration and reaction mass?

somewhere in a galaxy a long time ago I was informed that accelerating a spaceship at one gravity (Earth value) would result in near relativistic velocity after only one day (Earth value) - I was ...
19
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4answers
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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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2answers
130 views

How to use specific impulse for multiple stages

I am given a scenario where I need to create a program to give the initial launch mass of a spacecraft that can vary between 4 and 20 stages. I am given that the "specific impulse for all stages is ...
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2answers
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Is the mass of paint relevant in rocket design?

(Prompted by this answer): Do the designers of large rockets* (have to) take the mass of the exterior paint into account? If so, do we have examples of actual design changes/decisions based on this (...
3
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1answer
99 views

How is imbalance handled in the Delta IV heavy?

All the engines of the Delta IV are not ignited at the same time: One of the lateral engine is started few seconds before the other. I imagine there is a good reason for not starting all engines at ...
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0answers
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Mass/weight information about stage separation mechanism

How can I get mass/weight information about rocket stage separation mechanisms that are used in multi-stage rockets? I plan to create an excel table to compare stage separation mechanisms by weight ...
15
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1answer
526 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
99 views

Long, low mass data transfer wire options

does anyone have any suggestions for wired communications over long distances on the Lunar surface? The maximum length would need to be around 1km. Distributors like Gore and Axon make great ...
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2answers
2k 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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3answers
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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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0answers
67 views

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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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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2answers
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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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1answer
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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 ...
8
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3answers
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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.
2
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1answer
243 views

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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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 ...
3
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1answer
622 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 ...
10
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2answers
531 views

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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2answers
645 views

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
518 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 ...
6
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3answers
728 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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2answers
732 views

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 ...
4
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3answers
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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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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-...
3
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1answer
898 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? ...