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6 views

Did the ISS CREAM experiment actually get relocated?

A recent update (May 22) to the database for the NASA visualization tool DOUG shows that the CREAM payload has been relocated to the top of the Japanese Experiment Logistics Module - Pressurized ...
7 votes
4 answers
2k views

Power to grow food per person

Can I get a rough estimate of the power (in watts) needed to produce light to grow enough food for one person, using vertical farming of the kind proposed for space habitats? Any reasonable outpost/...
0 votes
1 answer
64 views

Example using NASA GMAT to model a sounding rocket launch

I'm wondering if anyone has an example GMAT script that describes a sounding rocket launch and return. Not necessarily looking for high fidelity but just something that shows the parameters for a ...
5 votes
2 answers
566 views

Rocket engine with lowest Isp to reach orbit

Which engine with the lowest possible specific impulse has reached orbit propelling a given rocket? There is a page at Wikipedia that compares orbital engines but some engines are missing Isp value ...
3 votes
1 answer
90 views

Where does this formula for the argument of periapsis come from?

I was looking at Poliastro/Hapsira python code determining orbital elements from the position and velocity vector. On this line, argp or $\omega$ is determined as (...
18 votes
1 answer
6k views

Person falling from space

A person at rest 500 km above the Earth falls straight downwards. She has a snug magical force field around her that is totally rigid and completely protects her from outside heat. The force field ...
1 vote
1 answer
181 views

How have rocket propulsion system designs developed over the years in terms of effectiveness?

I am working on a research project about developing rocket propulsion designs for school. More specifically, I am researching how rocket propulsion designs have changed over the last century, in terms ...
1 vote
0 answers
37 views

Testing astrodynamics software

As I’ve been developing my own solutions (and implementing existing ones) to problems in astrodynamics to solve textbook questions and to build applications, I’m becoming increasingly interested in ...
0 votes
0 answers
14 views

Issue in orbit propagator with wmm2020 output

I am trying to build an orbit propagator with input of latitude and longitude in wmm2020 to plot the magnitude of the geomagnetic field. The orbit seems good but the field plot is completely wrong. ...
3 votes
1 answer
224 views

Did New Horizons look for "sailboats" in the Pluto-Charon system's sailboat region? Did it pass through it or avoid it?

In this answer to If we could send an orbiter to the Pluto-Charon system, could we put it in a stable orbit? I wrote: Totally by accident I've just happened to run across the 2014 open access paper A ...
11 votes
1 answer
327 views

Why is the water pumped out of the holding tank a minute before Falcon 9 liftoff?

SpaceX Falcon 9 - starlink mission on October 5. Video : Why is the water discharged at T- 01m:30s from the holding tank far away from the launch pad? This was also ...
5 votes
1 answer
288 views

After a spacecraft departing from the ISS has performed its deorbit burn, what is the altitude at the perigee of its elliptical orbit typically?

I am attempting to quantify how aggressively returning spacecraft reenter the atmosphere. There is likely a trade-off between aerobraking more gradually and splashing down accurately. I'm hoping that ...
11 votes
4 answers
23k views

Transform ECI to ECEF

I need to transform ECI to ECEF coordinate. Here, I need the formula in math and algorithm. I have looking for the formula in the internet, but I can find one. I have x, y, z cartesian coord in ECI. ...
0 votes
1 answer
156 views

Why should nozzles be perfectly expanded?

If I understand it correctly, the only problem with an overexpanded nozzle is (aside from technical difficulties) that the surrounding atmosphere puts pressure on the exhaust gases and reduces engine ...
9 votes
2 answers
497 views

In Apollo hardware, why were sump tanks needed?

I'm looking at the Apollo CSM Propulsion Systems. These were bi-propellant hypergolic systems. However, for some reason each type of propellant was divided into a storage and sump tank. For example, ...
8 votes
1 answer
617 views

Apollo-SLA & LM air pressures at launch

At the time of launch what was the air pressure in the Apollo LM, and the spacecraft-LEM adapter section (SLA)? Was the air vented from the SLA as the vehicle entered orbit?
3 votes
0 answers
43 views

Pressurisation in the Apollo Lunar Module? [duplicate]

After the Apollo 1 fire, the Command Module atmosphere at launch was 15psi of 60:40 nitrogen:oxygen, which was allowed to vent down to 5psi during the ascent, and then slowly changed over to 5psi ...
-2 votes
0 answers
53 views

Could someone please explain to me how is du/dt = omega x u [closed]

hope you can help me out here. Basically, I know that du/dt = dtheta/dt*u_N (I'm sorry but I don't know latex) but how can I say that du/dt is equal to omega vectorial u where u is the unit versor ...
8 votes
1 answer
8k views

How far does the sound of a rocket launch carry?

Having never been to a rocket launch, can you tell me how far the sound carries? I can hear the rumble of F-15 Eagles take off from inside my office building five miles from the airport. An F-15C is ...
11 votes
2 answers
2k views

Why do cryogenic fuels want an extra pressure tank?

I do see the need to provide pressurizing gas with non cryogenic fuels (like RP-1) but if you require to have it at very low temperatures anyway to keep it liquid and the pressure in the tank drops, ...
1 vote
1 answer
158 views

What does w.r.t. mean? I've found it in the summary of jup365.bsp [closed]

Inside summary of the file jup365.bsp I have found this: ...
3 votes
2 answers
290 views

What is the oxygen filter on Super Heavy, and how could it get blocked on IFT-3?

https://en.wikipedia.org/wiki/SpaceX_Starship_integrated_flight_test_2 On February 26, 2024, SpaceX stated that the most likely root cause was filter blockage where liquid oxygen is supplied to the ...
1 vote
2 answers
191 views

Could Superheavy land downrange and return if Starship were launched from Boca Chica?

While answering a question about Starship versus skyhooks, I discovered that there is a big difference in payload between a Falcon 9 launch where the booster lands downrange on a drone ship and one ...
3 votes
0 answers
193 views

Cost breakdown of launch companies

One thing which I recently heard Peter Beck say in an interview with Tim Dodd was that the cost of running a launch company isn't primarily driven by the rocket itself, but the operations required to ...
5 votes
5 answers
3k views

Is a dome really the most efficient way to contain gas in a vacuum?

It's pretty common to see some artist or even engineer come up with an idea of a lunar or Martian colony with a big ol' glass dome up top. And we seem to have been doing this since the 60's. But ...
2 votes
1 answer
113 views

How much more stressful would the Indian Ocean reentry have been for Starship IFT-3?

The flight tests were originally supposed to end in the Pacific, but was switched to a steeper trajectory that ended in the Indian Ocean for IFT-3. Assuming all had gone perfectly, how much harder ...
3 votes
0 answers
45 views

Why my calculations for the eccentric anomalies at the start and end of an interplanetery transfer seem to be off?

For a game, to determine an interplanetary transfer I have implemented the method from here. Using the data for their example problem, I get the result with the lowest $\Delta v$ which appears ...
1 vote
0 answers
112 views

Any ideas?: Calculating wet-mass and burn altitude for a Mars landing, using a Python simulation

In this post, I will explain the problem, provide some detailed context, and finally explain what I am searching for (what my question is basically). First of all, this should be quite a fun but ...
11 votes
2 answers
1k views

Aborting a de-orbit maneuver

I was contemplating on how a de-orbit may be abandoned post completion of the orbit burn, say, from LEO. A situation in which this might be necessary would be detecting a breach in the heat shield ...
6 votes
2 answers
491 views

Can Starship land on the moon horizontally?

Since the landing engines will be halfway up the body anyways, how about putting the landing legs to extend perpendicular and land with nose and main engine bay pointing towards their respective ...
35 votes
7 answers
15k views

How could a 90 m/s delta-v be enough to commit the space shuttle to landing?

Wikipedia claims (although with no citation) that in order to make the space shuttle land, an initial powered delta-v of 322 km/h was applied in orbit, retrograde to the shuttle's orbit. 322 km/h is ...
4 votes
1 answer
199 views

Would that asteroid transport be possible?

I did the mistake of watching an episode of the Science Fiction series "For All Mankind". There they are trying to catch an asteroid in order to bring it back to Mars. I know this series is ...
3 votes
1 answer
145 views

Could asteroid mining benefit human kind?

If we ever set out into space to mine stuff like asteroids, and utilized the resources from said asteroid, would we be a more advanced civilization (when I mean advanced I mean like building stuff ...
4 votes
0 answers
85 views

Which LEO satellites have publicly available accurate position information?

I am working on a orbit propagation project and need accurate position information of LEO satellites. I have until now used Sentinel 3A/3B (~800 km altitude), whose ECEF coordinates I can get with a 1 ...
0 votes
2 answers
89 views

If we could mine asteroids, how would we get the stuff mined from said asteroid back to earth?

I was thinking of some contraption that would suck up the material from said asteroid and put it in some type of container thingy that would then be transported to a shuttle that would then get sent ...
4 votes
1 answer
491 views

Does earth's revolving around sun affect polar orbit ground track?

As the earth revolves around the sun, does the ground track of a polar orbit change? I realize the oblateness of the earth causes precession of the nodes, I want to know if there's another effect. As ...
16 votes
3 answers
4k views

Has any piston machine been used on a space mission?

Inspired by question about engine lubrication in space. Piston engines are not used for propelling spacecraft, but there are some possible uses for especially Stirling engines and compressors: ...
3 votes
1 answer
149 views

Other than rockets, have internal combustion engines run in space?

According to https://en.wikipedia.org/wiki/Advanced_Cryogenic_Evolved_Stage The Advanced Cryogenic Evolved Stage (ACES) .. proposed (using) a lightweight internal combustion engine to use hydrogen ...
3 votes
0 answers
141 views

Does Starship run on Slushies?

Cryogenic slush (a mixture of liquid and solid) can potentially store propellants at higher density than cryogenic liquid. For instance, hydrogen slush is 16-20% denser than liquid hydrogen. https://...
8 votes
1 answer
1k views

At what altitude do the effects of atmospheric drag completely disappear?

The spate of K-questions got me thinking: At what point does atmospheric drag disappear1 with the pressure from sunlight, solar wind, or other forces becoming overwhelmingly dominant? I'm guessing it'...
8 votes
1 answer
2k views

How does flying a steeper entry trajectory make the exclusion zone smaller?

This interesting answer Why did SpaceX change the landing site from the Pacific (ITF-1, ITF-2) to the Indian Ocean (ITF-3 and subsequent flights)? contains the following paragraph: However this type ...
8 votes
3 answers
1k views

Why does Earth's atmospheric density have a big "knee" around 100 km? Is there a good analytical approximation?

I've used a quick very rough approximation of the drop of atmospheric density with altitude in this answer and in this answer by using a single exponential and scale height parameter, but that's not ...
6 votes
0 answers
80 views

What is the lowest viable circular orbit around Mars that can last at least one week?

Supposing you wanted to launch a spaceship from the surface of Mars into orbit around Mars. It would stay in orbit for up to one week while you prepared a second rocket that would dock with it to ...
5 votes
2 answers
484 views

Crew Dragon: Could launch escape thrust determine payload capacity?

The superdracos in Dragon's launch escape system each produce $\color{black}{\texttt{71.2 kN}}$ (16,000 lbf) of thrust. There are eight superdracos, giving a combined thrust of $\color{black}{\texttt{...
3 votes
0 answers
76 views

Exploration EVA by donning a dust protection suit over a pressure suit

It seems to me that a pressure suit for the Moon or Mars would be a lot easier to design if astronauts were simply required to don a dust protection suit over the pressure suit before going outside. ...
7 votes
3 answers
300 views

Overcoming the Moon Dust Problem: Are We There Yet with Spacesuit Technology?

I've been mulling over a thought for quite some time now. As we gear up for a return to the Moon and possibly Mars, I can't help but think about one of the major issues from the Apollo missions: the ...
9 votes
4 answers
4k views

Will there be another joint International Space Station (ISS) after the current is retired?

Currently, as far as I know, the Chinese are building their own "ISS". I heard that they are open to welcoming most EU countries. Does anyone have heard any news on building a newer "...
5 votes
2 answers
695 views

Why did SpaceX change the landing site from the Pacific (ITF-1, ITF-2) to the Indian Ocean (ITF-3 and subsequent flights)?

This statement from the FAA is quoted on https://wccftech.com/spacex-receives-faa-clearance-for-starships-third-test-5-indian-ocean-landings-planned The need for (switching landing to the) Indian ...
1 vote
0 answers
65 views

Exploring DNA-Based Hard Structures for Space Applications—Looking to learn more

I recently had a fascinating conversation with a student about to graduate with a master's in microbiology. He shared that he’s lined up a job where he'll work on developing "hard structures"...
3 votes
0 answers
57 views

What online courses teach you hands on AOCS GNC?

I am looking for online courses that teach you "attitude and orbit determination and control systems" and "guidance navigation and control" with a focus on satellites or space ...

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