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Questions tagged [mass]

Questions regarding the mass of spacecraft or other objects

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Has NASA published any information that better quantifies the mass budget requirements for "back to the moon ... this time to stay"?

I'm interested in those elements of their plans that will help me to estimate a yearly mass budget, such as how many crew at a time, how long will they stay each time, how often they will be rotated ...
5 votes
1 answer
147 views

square-cube law and thermal protection tiles (TPS)

Yesterday, I asked a question about the square-cube law and propellant tanks. Do larger rockets tend to have a better mass ratio due to the square cube law? I have a very similar question about ...
10 votes
3 answers
3k views

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.
4 votes
0 answers
123 views

Mass Breakdown of Apollo CSM by Subsystems? (also Cost Breakdown)

I am looking for a mass breakdown of the Apollo Command and Service Module by subsystems, like this Lunar Module's chart from the NASA publication After LM. I am particularly interested in how much of ...
3 votes
3 answers
1k views

Would orbital ring platforms affect the orbit of a planet?

If we built an orbiting platform of sufficient mass (let's say, made from harvested asteroids) that was anchored at both poles of the planet it surrounded, would such an addition to the planet's mass ...
0 votes
0 answers
51 views

Hypersonic dynamic shift in large vs. small lifting bodies

Background: Lifting bodies have been tested at small scales, though not during re-entry. For instance: the NASA HL10 Such Lifting-Body designs are seemingly here to stay with craft such as Dreamchaser ...
6 votes
2 answers
257 views

What is the largest possible rocky body? [closed]

Suppose you start with a rocky sphere about 12,742 kilometers in diameter and continuously add more rocky material such that you don't smash this sphere to bits. What is the upper limit for this? ...
3 votes
0 answers
119 views

How do ablatively cooled rocket engines compare to regeneratively cooled ones, in terms of mass?

Assuming equivalent thrust and single continuous burn duration, is there a figure that roughly tells the difference in mass between these two engines cooling methods? This question focuses on first ...
6 votes
1 answer
1k views

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 ...
5 votes
4 answers
3k views

With increased space exploration missions, are we affecting earth's mass?

This questions may seem naive, but, worth pondering: As humans keep sending more and more missions to space (outside earth's system), the earth is being affected in the following ways: Earth is ...
8 votes
3 answers
375 views

Do larger less dense objects heat less while entering the atmophere?

When a space craft enters the atmosphere, it gets hot and heat shielding is needed. Do objects with more surface area and less density heat up less then heavier, smaller objects? Could an object with ...
1 vote
0 answers
102 views

How heavy is an orbital pogo stick?

Moving people from a A to B in space often requires a significant change in velocity, requiring propellant eating into the mass budget. But most of this propellant is "wasted" in moving a ...
5 votes
3 answers
5k views

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-...
1 vote
0 answers
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Time a rocky satellite in lunar "frozen" orbit spends in Earth's umbra during total lunar eclipse

I am wondering how long a large satellite in a lunar frozen orbit would remain in the Earth's umbra during a total lunar eclipse. The satellite is spheroid with a diameter of 200 km. Let us say that ...
7 votes
1 answer
303 views

Why will Starlink Gen2 be so big and heavy?

Apparently, the mass of a Gen2 Starlink satellite will be around 1 metric ton. It will also be too large to fit into a Falcon 9 fairing. Given that it's basically still a "flying router", ...
15 votes
6 answers
707 views

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 ...
8 votes
3 answers
2k views

What determines the orbital speed around a Lagrange point?

What value of M should I use to calculate the speed of a satellite orbiting a Lagrange point where there exists no mass?
2 votes
1 answer
335 views

Problem in finding propellant mass using rocket equation, where total mass includes components dependent on propellant mass

Formulation: $$e^{\Delta v/v_{exhaust}} - 1=\frac{mass_{fuel}}{mass_{structure}}$$ $$\text{let } k=e^{\Delta v/v_{exhaust}} - 1 \implies mass_{fuel}= k \times mass_{structure} $$ According to SMAD (...
9 votes
1 answer
394 views

Does a persons weight affect 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 ...
7 votes
0 answers
544 views

How much does JWST actually weigh?

I recently had to delete my answer to Why doesn't James Webb have a larger supply of thruster propellant? because @NgPh noted: As the last update, JWST weights 6200 Kg. jwst.nasa.gov/content/about/...
1 vote
1 answer
2k views

What is Rocket Lab Electron's dry mass?

Does anyone know how heavy Rocket Lab's Electron rocket is without fuel? Or do you by chance have any information about the fuel capacity of the first and second stage? I'm trying to model its flight ...
19 votes
3 answers
6k views

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 ...
3 votes
1 answer
538 views

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 ...
26 votes
3 answers
6k views

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 ...
4 votes
0 answers
90 views

How to estimate total CO2 emission per year due to rocket manufacture?

I'm working on a study on greenhouse gas emissions related to rockets. While I have the post-launch (atmospheric) emissions, I need data for emissions related to production. For example, according to ...
15 votes
1 answer
3k 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 ...
14 votes
2 answers
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 ...
2 votes
1 answer
656 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 ...
3 votes
0 answers
324 views

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 votes
1 answer
247 views

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 ...
7 votes
1 answer
4k views

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 votes
2 answers
307 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 votes
1 answer
466 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 ...
1 vote
0 answers
122 views

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 ...
0 votes
1 answer
252 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 ...
8 votes
5 answers
2k views

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 votes
1 answer
227 views

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 ...
2 votes
0 answers
97 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 ...
4 votes
0 answers
229 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 ...
1 vote
0 answers
213 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 votes
1 answer
265 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 ...
6 votes
2 answers
411 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, ...
9 votes
3 answers
3k views

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 votes
1 answer
2k 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 votes
1 answer
206 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 ...
3 votes
0 answers
70 views

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 ...
11 votes
4 answers
4k views

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 ...
1 vote
2 answers
425 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 votes
4 answers
6k views

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 ...
2 votes
2 answers
324 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 ...