# All Questions

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26 views

### What is the longest string of code ever executed over the earth? [on hold]

Omitting navigation and other craft operations, what is the longest string of code that has been executed over the earth?
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### Can effective thrust in the more dense layers of the atmosphere be considered constant (as approximation)?

I am reading some course material about the 'Thrust load ratio'. It states the following: The thrust load ratio is: $Psi = {T \over Mg}$ $T$ being the effective thrust, equal to the actual (...
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### Why was ramjet fuel used as hydraulic fluid during Saturn V checkout?

Fuel is also used within the engine as a lubricant and as a hydraulic working fluid, though before launch, RJ-1 ramjet fuel is supplied from the ground, it being more suited for this purpose. ...
16 views

### Identify these astronauts

In December 2017 former astronaut Janet Kavandi tweeted a picture of a group of women astronauts taken at an astronaut reunion. There are nine of them I can't identify, can anyone name them? I've ...
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### Could the sulfuric acid in the atmosphere of Venus be heated enough by concentrated sunlight to create water and oxygen?

The atmospheric pressure and temperature at about 50 to 60 km above the surface of Venus is nearly the same as that of the Earth, making its upper atmosphere the most Earth-like area in the Solar ...
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### Launch vehicle trajectory tool for ascent phase to orbit using PYTHON

Currently, I am developing a trajectory optimization tool for launch vehicle from lift-off to orbit using python for my project. Since I'm new to optimization problem, I am finding it hard to ...
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### Colonisation of Titan

Titan has an abundance of hydrocarbons. Earthbound animals live on carbohydrates that are metabolised by elements like Oxygen that is found on Earth. Is there a possibility of different metabolism ...
31 views

### When does the space shuttle stop its gravity turn?

I am trying to model the launch of the space shuttle (up to 120km of altitude) from Cape Canaveral, Florida. In order to do so I would need to know when the gravity turn part of the flight starts and ...
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### Where can I find launch trajectory data of the space shuttle?

I am trying to mathematically model the launch of the space shuttle (up to 120km altitude) from Cape Canaveral Florida. It would be really handy if I could check my calculations with some real launch ...
54 views

### Saturn I's four outer engines' gas generator exhaust, why not vent to the side like the four inner engines?

At about 04:58 in Scott Manley's new video NASA Might Be Giving Away A Saturn I Rocket - Here's Why I Love This Vintage Booster he says: So the four engines in ...
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### Did von Braun have “a thing” for fins? Why did Saturn I block 2 get fins because it's a “von Braun” rocket?

At about 05:55 in Scott Manley's new video NASA Might Be Giving Away A Saturn I Rocket - Here's Why I Love This Vintage Booster he says: So the Saturn; the first ...
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### What was the quickest launch-to-complex-milestone time achieved by a shuttle mission?

The baseline reference mission "3B" had the shuttle launching from Vandenburg, rendezvousing with and retrieving a satellite, and returning it to Earth all within a single orbit: http://www....
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### What is the closest distance SpaceX's Tesla Roadster (Starman) will ever be to Mars?

Elon Musk's own personal Tesla Roadster launched on the Falcon Heavy in November 2018 and unfortunately overshot the orbit of Mars. This short animation shows the trajectory of SpaceX's Roadster. It ...
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### Why did Orbex choose propane as its fuel?

As a follow up to Are there liquid fueled rocket boosters having coaxial fuel/oxidizer tanks? and thinking about JCRM's answer pointing the issue of having a huge contact surface between inner and ...
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### 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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### Will the Artemis lunar landers provide some privacy?

As we learned in Did astronauts on the moon poop in front of each other the Apollo lunar landers provided no privacy. The Artemis missions will have members of both sexes, so privacy becomes a bit ...
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### Will the Mars helicopter be able to remove the dust from solar panels?

Athough i'm not that worried about Insight's solar panels that i didn't sleep well because of that, this question got me thinking ! The Mars Helicopter Scout is a planned robotic helicopter that ...
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### How does one calculate the argument of periapsis of an orbit after an arbitrary maneuver?

Given a satellite in an equatorial orbit, a specific prograde or retrograde burn is executed at an arbitrary point within the orbit, and I need to calculate the resulting orbital ellipse. The ...
289 views

### How do ultra-stable oscillators for spacecraft work?

Many spacecraft carry "ultra-stable oscillators" for ranging and related measurements, but I can't quickly find any info on how these actually work. Are they just very pure quartz crystals, or do they ...
47 views

### Why did no astronaut land on the moon more than once? [duplicate]

Wouldn't it be better to send people to the moon that already have experience? Or was the time between the starts so short that it was not possible to reuse the crew of Apollo 11 for (say) Apollo 17?
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### What are the key dimensions of the new IDA docking ports on the ISS?

I'm building a 3D model of the power and propulsion module of the Lunar Gateway, and I'm trying to establish a few dimensions so it's easier to make it accurate. It seems from the artwork that it uses ...
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### Why were some early interplanetary probes pressurized?

Mariners 2 through 9, and the Soviet spacecraft of that era, sometimes suffered from leaks that impaired or disabled parts of their scientific payloads. What kinds of sensors couldn't work in vacuum? ...
3k views

### Will some rockets really collapse under their own weight?

There are a couple of answer here talking about, rockets collapsing under their own weight. One claims it actually happened another says it is possible. I once saw a pic of a retired Atlas on ...
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### What is the optimal inclination change strategy?

Consider a transfer between two circular orbits of similar radius, the only difference being the inclination difference, $\alpha$. What's the minimal $\Delta v$ required to perform this transfer? ...
1k views

### Are there liquid fueled rocket boosters having coaxial fuel/oxidizer tanks?

Reading this question, instead of stacking two tanks, are there boosters where tanks are coaxial, (like a thermos bottle) having a trussed or tridimensional structure between inner and outer tank? ...
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### What materials should I use to make a suborbital amateur rocket and where can I buy them? [on hold]

I’m trying to make a suborbital rocket to get some pictures of the Earth but I’m not sure what material’s to use and where to get them. I’ve been thinking of titanium for the shell but I’m not sure ...
72 views

### Where on Mars will China's rover land?

Inspired by this question about all the missions to Mars in 2020, where on this planet will the rover of the mission that China has planned, land and operate ?
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### What are/have been some dedicated launchers for the 100-1000 kg to LEO(sub 1000 km)payload market?

Today's satellites are between 50-500 kg mostly apart form cubesats and their larger versions(3U-16U), which have brought the demand for microlaunchers. Rocket Lab's Electron, is one great example. I ...
79 views

### Whats the difference between cryogenic and cryo storable rocket engines

I've read about cryogenic storable liquid rocket engine but since it doesn't refer to its fuel, I want to understand the difference between a cryogenic and a cryo-storable engine. The term cryo-...
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### Is the amount of accurate information in a TLE equal to that of a single state vector?

My question is basically regarding whether there is orbital information "lost" when converting from a Two Line Element set (TLE) to a state vector. Given that the following are true: I have a TLE, ...
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### Why did Mercury use multiple CAPCOMs while Apollo did not?

A spacecraft needs multiple receiving stations to prevent its radio signals from being blocked by Earth. Wikipedia has a map of the ground stations used for the Mercury missions. The Right Stuff ...
5k views

### What would it take to get a message to another star?

Let's assume that we've somehow detected the existence of an extraterrestrial civilization through "passive" means, such as detecting a suspicious exoplanetary atmospheric signature. We're now hoping ...
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### Where are the 6 22-N OSIRIS-REx engines?

Does anyone could link an image/3D model/photo that shows the 6 22-N engines? Related question: OSIRIS-REx engines location.
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### How did astronauts get from the command module into the LEM, and vice versa?

After seeing many simulations of the command/service module doing a 180 and docking with the LEM, it occured to me that something didn't look right. At the nose of the command module there appears to ...
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### ESA/Roscosmos, China, UAE and US all sending missions to Mars in 2020 (Summer of L̶o̶v̶e Mars); how far apart are the frequencies?

Gizmodo's Second failure of ExoMars parachute test throws schedule in jeopardy says: ExoMars 2020 is due to launch during a narrow window open between July 25th to August 13th 2020, during which ...
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### Why aren't rockets built with truss structures inside their fuel & oxidizer tanks to increase structural strength?

I've been wondering how a rocket fuselage can support all the weight of the upper stages when it is only made of a cylinder of very thin sheet metal. (Especially considering acceleration, vibration ...
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### Are there both “lake” and “sea” designations on Titan? Officially or otherwise?

@TomSpilker's excellent answer to How (the heck) do they know some lakes on Titan are 100 meters deep? says at the very end: As far as the lakes (smaller than the seas) go, as the sources you cite ...
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### Puzzler: which Apollo 8 astronaut would have been positioned furthest sunwards 20 minutes after lunar insertion?

This Classic @DavidHammen answer to the question Who has been the closest to/furthest from the Sun? says: This bodes well for an Apollo astronaut being the person closest to the Sun, but bodes ill ...
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### OSIRIS-REx engines location

I'm trying to locate all the OSIRIS-REx engines. Here: http://spaceflight101.com/osiris-rex/osiris-rex-spacecraft-overview/ (Propulsion System) I read that there are: 4 x 275 N, 6 x 22 N, 16 x 4.5 N ...
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### Is the BEAM module as good as a rigid module in terms of radiation/thermal properties?

It seems that NASA is going to stick with the BEAM module on the ISS for quite some time, and is currently using it for storage. That's pretty cool. However, I was wondering if the BEAM module could,...
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### How much is horizontal splashdown to land reusable vehicles useful / feasible? [closed]

To use a pool as landing field with non-flammable oil/lubricant. A pool has different depth to achieve minimal volume. So, lifting-body reusable vehicle/booster can have belly(horizontal) landing on ...
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### Is it possible to use hybrid propulsion to drive the turbopump?

Turbopump are driven either by a preburner or by an electrical engine (OK this technology is quite new and currently in 2019 only used on the Rutherford engine). If I understand correctly, using ...
2k views

### Double redundancy for the Saturn V LVDC computer memory, how were disagreements resolved?

In the Smarter Every Day video How did NASA Steer the Saturn V?- Smarter Every Day 223 Destin is talking with Luke Talley about the memory modules used in the Saturn V LVDC computer. This computer ...
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### What is the basis of the new Russian nuclear rocket propulsion?

The New York Times' Russia Confirms Radioactive Materials Were Involved in Deadly Blast discusses the potential nuclear aspects of the recent missile test and references several time the possibility ...
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### What is/were the Soviet/Russian qualifications for a capsule communicator?

The person in mission control responsible for speaking to American crews is called the capsule communicator or CAPCOM. Historically this person has been another astronaut -- as they would have the ...
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### What radio frequencies were used by the Soviet space program circa 1961? (“Lost Cosmonaut” recording)

The recent Joe Scott video The Mysterious "Lost Cosmonaut" Recording | Random Thursday describes radio recording said to have been made by the Judica Cordiglia brothers from Italy in the early 1960's. ...
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### Why were blood and hair follicles from 25 people put on the Moon?

The Wired.com article A Crashed Israeli Lunar Lander Spilled Tardigrades on the Moon says: Spivack had planned to send DNA samples to the moon in future versions of the lunar library, not on this ...