All Questions

Filter by
Sorted by
Tagged with
23 votes
3 answers
4k views

Was Starship’s “launch window” administrative, rather than due to orbital mechanics?

According to Wikipedia, a launch window is the time period on a given day during which a particular rocket must be launched in order to reach its intended target. SpaceX’s internet launch coverage ...
Woody's user avatar
  • 18k
6 votes
1 answer
2k views

Did Starship Ship 25 burn up on re-entry?

SpaceX Starship Ship 25 launched and managed a successful separation from the booster and reportedly made it into space before the autonomous flight termination system activated, destroying the ...
Wiggo the Wookie's user avatar
2 votes
3 answers
191 views

Disposing of Obsolete Satellites by Propelling to the Sun

I'm not scientifically adept, so bear with me. Would it be feasible to retain enough fuel on new satellites/space stations, etc., that we could dispose of them when obsolete by sending them to the ...
user avatar
3 votes
0 answers
92 views

How much lead (kg) would you need to survive for an extended period of time in Jupiter’s radiation belts?

Imagine you have a 1 by 1 by 2 meter chamber that a human needs to survive in for one year, while orbiting in Jupiter’s radiation belts. How much lead, in weight, would have to surround the chamber to ...
ThatDemoGuy's user avatar
2 votes
3 answers
798 views

(How) would the water deluge system impact Starship superheavy captures?

(How) would the water deluge system impact Starship superheavy captures, when they eventually manage to return to starbase? Could it be turned on during landing attempts? Would that reduce lift (...
Daniël van den Berg's user avatar
4 votes
2 answers
231 views

Does swimming experience help to adapt to weightlessness?

In the story I currently write, I have a character who has been a passionate swimmer for decades. Now, she goes to space. I wonder how she would adapt to weightlessness, and would her swimming ...
Krišjānis Liepiņš's user avatar
2 votes
0 answers
36 views

Nozzle contour estimation (Merlin 1D Vacuum)

I would like to run a fluid simulation of the diverging section of a Merlin 1D Vacuum engine. While most relevant parameters (such as expansion ratio, flow rate, and nozzle area) are readily available,...
FTT's user avatar
  • 149
2 votes
1 answer
113 views

How does SpaceX get its boosters from the ASDS to SLC-40?

Getting a freshly-landed booster from a drone ship to pad 39A seems straightforward: there's a deepwater channel from Port Canaveral to a dock next to the VAB. Sail the ASDS up, lift the booster off ...
Mark's user avatar
  • 14.6k
4 votes
2 answers
460 views

Are rockets deliberately throttled back towards the end of the burn to spare crew and airframe g-forces?

Throughout its burn, a rocket gets lighter as propellant is consumed. As a result, acceleration (and g-force) increase. In the shuttle, the SSMEs were throttled back towards the end of the burn ...
Woody's user avatar
  • 18k
0 votes
0 answers
88 views

Can coking be avoided by pumping fuel after shutdown?

As I understand it, coking in kerolox engines occurs when the engine shuts down and fuel flow stops, causing fuel still in the coolant channels to overheat and decompose. Can this problem.be avoided ...
Abdullah's user avatar
  • 2,645
1 vote
0 answers
31 views

Definition of "elevation mask" when it comes to sensors and ground stations?

My understanding is that elevation mask is a term for purposely limiting sensor observations, usually on the ground, by intentionally blocking sky observations from the horizon to a specific elevation....
prepont's user avatar
  • 21
2 votes
1 answer
175 views

On space stations, what do they do with small solid particles which are free floating?

I heard a claim that a piece of graphite, of half a millimeter size which broke from a pencil can kill a person who inhales it. Is this a major problem or an exaggeration? In a gravitational ...
Anixx's user avatar
  • 3,117
4 votes
0 answers
87 views

Do ISS astronauts have a preference for when EVA tasks are scheduled with respect to lighting conditions?

Given the choice, do ISS astronauts prefer to schedule EVA tasks on the “day light” side of the ISS, the “shadow" side of the ISS or in the shadow of Earth’s night side? I suspect the intense, ...
Woody's user avatar
  • 18k
3 votes
0 answers
71 views

Have spherical dish antennae been used with Molniya satellites to avoid switch-over signal loss?

Molniya-orbit communication satellites work well for ground locations near the poles. These high eccentricity, highly inclined orbits, with a period of 12 hours, “loiter” for about 6 hours over the ...
Woody's user avatar
  • 18k
9 votes
2 answers
3k views

Term for deformation due to gravity

In this video, If you look closely, you can see the smaller planet deforming before the actual collision. I think I remember a term existed for this. I think it is ...
user22859957's user avatar
3 votes
1 answer
138 views

Could mirrors used in a Dyson Swarm be made from asteroids in the inner asteroid belt?

In this video from Kurzgesagt they said that one would need to disassemble a whole planet to build a Dyson swarm around the sun. The video went on about mining Mercury and using the materials ...
The Rocket fan's user avatar
10 votes
3 answers
3k views

What is the largest object/mass that can survive entry into the earth's atmosphere from space without heating to 40 degrees C, or above?

This question is of interest because there are terrestrial organisms, such as bacterial and fungal spores, and even complex multicellular organisms, such as tardigrades, which can survive deep space ...
Mike Darwin's user avatar
6 votes
1 answer
253 views

Why use plutonium when sunlight is everywhere? Any proposals to use concentrated solar power instead of Pu238 as a heat source for TGs?

Why use plutonium when sunlight is everywhere? The case for powering thermoelectric generators (TG) with concentrated solar rather than plutonium: Spacecraft operating in the inner Solar System ...
Woody's user avatar
  • 18k
-2 votes
0 answers
80 views

Why doesn't the starship superheavy booster need heat shielding [duplicate]

Why doesn't it need heat shield while the second stage does?
Rocketsss's user avatar
1 vote
0 answers
61 views

What is the feasibility of High Resolution (< 5m) Hyper spectral Imaging satellite?

Many companies are coming up with claim of less than 5m resolution of hyper spectral imagery, although the payloads of such caliber could be built, I have come to the understanding that SNR would be ...
Bharath Simha Reddy's user avatar
3 votes
1 answer
209 views

Who is manufacturing the solar panels for Starlink satellites?

I am trying to understand the supply chain behind the Starlink Satellite Constellation. I am wondering how SpaceX is able to source those many solar panels. If somebody could give a brief explanation, ...
Bharath Simha Reddy's user avatar
11 votes
5 answers
1k views

In circle orbit, give a delta V to a satellite, how to find final orbit altitude?

I think this is a very very simple question for me, but unfortunately I cant solve it... A satellite is orbiting in a circular path at an altitude of 600 kilometers. If the satellite is capable of ...
Achilles chan's user avatar
1 vote
0 answers
85 views

Aspiring to Build a Space Rover from Scratch – Where to Begin? [closed]

What fundamental concepts, beginner-friendly resources, or online courses would you recommend for someone starting with little to no background in robotics? At first, I want to build a an autonomous ...
Md Ghufran Fazal's user avatar
3 votes
2 answers
312 views

If a baby was born on the ISS, what would its nationality be?

If a baby was born on the ISS, what would its nationality be? Many countries grant citizenship to any baby born within their territory, but the ISS is not national territory ... or is it? If a ...
DuckyPolice alt's user avatar
5 votes
2 answers
469 views

What does a "handover" really mean in satellite communications?

I am working on simulating a satellite constellation and I keep coming across the term "handover". My general understanding is that a handover is when a ground station switches its connected ...
Luca Petrescu's user avatar
1 vote
0 answers
100 views

Are smaller rockets easier to land? [closed]

Is it easier to land a smaller rocket compared to bigger rockets?? Since they are lighter
Rocketsss's user avatar
10 votes
1 answer
2k views

How is hot staging of Starship expected to provide such a large (10%) increase in total mass to LEO?

there's a meaningful payload to orbit advantage with hot staging that is conservatively about a 10% increase (Elon Musk during Twitter Spaces interview on June 24th, 2023, timestamp 37:13) In a line ...
Ingolifs's user avatar
  • 6,418
1 vote
0 answers
72 views

Single shaft turbopump vs two turbopumps

What are the pros and cons of using same turbopump for fuel and oxidizer and using 2 different pumps for both?
Rocketsss's user avatar
2 votes
2 answers
1k views

Is there an anomalous variation of distance between Earth-Moon during a lunar eclipse?

Apart from normal (expected) variation of distance between Earth and Moon in any given time interval, what happens during a lunar eclipse by way of some unexpected (anomalous) deviation? Have lunar ...
gerryD's user avatar
  • 87
3 votes
0 answers
49 views

Why did the Apollo 16 crew wait until Station 8 to sample ray material from South Ray (instead of earlier during EVA 2)?

During EVA 2 on Apollo 16, the crew planned to sample material from an ejecta ray from South Ray crater at Station 8. Earlier during that EVA, the mission plan had them drive through a continuation of ...
olamarre's user avatar
  • 887
32 votes
1 answer
4k views

Apollo 13's plutonium RTG re-entry into the Tonga Trench: Good shootin' or good luck?

Plutonium powered RTGs are encased to survive re-entry. According to the Wikipedia article on Apollo 13 RTGs were used to power … the scientific experiments left on the Moon by the crews of Apollo …...
Woody's user avatar
  • 18k
8 votes
1 answer
127 views

Understanding and breaking down pointing requirements

“< 1 deg, 3σ total angle pointing stability” - What does the 3sigma indicate? Does this mean that 99.7% of the total pointing error (which I assume is computed via a sim), is within 1 deg? If it ...
NewEngineer839292's user avatar
14 votes
2 answers
1k views

Does the atmospheric pressure of Mars fluctuate because of the seasonal evaporation of the polar ice caps?

The carbon dioxide ice on the Martian poles are known to evaporate every summer and re-deposit every winter. Where does this carbon dioxide 'go' and does it mean there is a seasonal variation in the ...
Duke O's user avatar
  • 341
3 votes
1 answer
96 views

Which SPICE kernels I have to load to calculate state vector of the outer planets

I'm developing a software to show the planets in the sky. I have loaded the following kernels: ...
VansFannel's user avatar
20 votes
3 answers
5k views

Why do the boot prints on the moon appear bright in some photographs or film?

I've seen that in some videos or photos of the moon mission, the boot prints appear brighter relative to the untouched ground: But in some other cases, they are the same brightness as the ground: Is ...
spaceamoeba1010's user avatar
20 votes
1 answer
3k views

Why are the Martian poles not covered by dust?

The Martian surface is known to have periodic 'dust storms'. Depictions of Mars typically show poles with ice at the surface. If that is the case why are the Martian poles not blanketed with a thick ...
Duke O's user avatar
  • 341
1 vote
0 answers
108 views

Does an overexpanded nozzle behave like a suction cup?

It is generally said that, to obtain optimal specific impulse, a nozzle should be just the right size that the exhaust pressure is equal to the ambient pressure. Quoting this answer, a relevant ...
Charles Staats's user avatar
0 votes
2 answers
160 views

Which satellite is this very bright object? - part 2

A few weeks ago, I asked the same question about a bright object that I observed, initially thinking it wasn't Venus, but was told that it actually was Venus. Oops, fair enough. Here's another bright ...
Bigbio2002's user avatar
1 vote
0 answers
69 views

How to maintain minimum distance between satellites for duration of their orbits

I am working on a simulation in python that involves propagating hundreds of satellites over time. For simplicity, let's assume I have satellites at only a single inclination separated into multiple ...
Luca Petrescu's user avatar
2 votes
2 answers
114 views

What is the prevalence of nitrogen, phosphorus, and potassium in the asteroid belt and in comets?

As someone with a light background in controlled-environment agriculture, I'm familiar with the importance and use of N/P/K in growing useful plants. This got me thinking about how common these ...
Michael Bonnet's user avatar
12 votes
3 answers
5k views

Why does the Curiosity rover camera image resolution have "milliradians" as a unit?

NASA's published specs for the Curiosity rover cameras says that the image resolution is in milliradians per pixel. Which is odd because image resolution is measured in physical size units, i.e. ...
spaceamoeba1010's user avatar
4 votes
0 answers
57 views

What document describes the scientific benefits of the LRV through an increase in the diversity of rocks returned by Apollo 15-17?

Logically, it makes sense that the rock samples returned by the Apollo 15-17 missions tend to be more diverse than the ones returned by previous missions. The astronauts could reach regions of ...
olamarre's user avatar
  • 887
6 votes
0 answers
149 views

Why did Voyager not use error correction coding for uplink?

Error correction coding was used for downlinked Voyager data, but why not for the uplink direction (if I'm correct in thinking it wasn't)? According to Edelson et al. 1979 "Voyager ...
Larry Gilman's user avatar
2 votes
0 answers
96 views

Is there any data for space debris that I can use to develop an AI model to predict the orbital decay time?

I need to develop a model to predict the orbital decay time for my graduation project but I searched for data that can help in that project and I failed to obtain such data. Can any one suggest a ...
amr ehab abdelhamed's user avatar
4 votes
0 answers
102 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 ...
mini earth's user avatar
3 votes
0 answers
54 views

Modeling Spacecraft Jitter from Reaction Wheel Imbalances

I am working on a project trying to model a satellite's pointing error caused by jitter from the reaction wheels. I have found a couple of papers (Paper 1 and Paper 2) which implement the simple model ...
Sam's user avatar
  • 73
3 votes
3 answers
529 views

How do you design a spacecraft with a spinning section for "artificial gravity"?

Science fiction spacecraft sometimes have a section that spins to provide "artificial gravity" through centrifugal forces. I'm thinking in particular of the Discovery spacecraft from the ...
John McCarthy's user avatar
0 votes
0 answers
45 views

Methane vs propane as rocket fuel [duplicate]

How would propane compare with methane as rocket fuel? Propane can also be stored as liquid under pressure.
Rocketsss's user avatar
-4 votes
2 answers
201 views

Why does centrifugal force cause gravity?

I have read several space books on processing resources in space. They talk about using distillation by rotating a section. WOuldn’t the centrifugal force cause the mixture to separate by its self? ...
11111's user avatar
  • 81
0 votes
0 answers
45 views

How can I get the CAD model and dimensions for the connector support of a space launcher?

I am a university student and want to do topology optimisation and additive manufacturing research for this component but cannot seem to find the accurate dimensions for it. I would be glad if anyone ...
sharps's user avatar
  • 1

15 30 50 per page