# All Questions

9,702 questions
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### What was the last message Opportunity sent?

Everybody seems to be abuzz with the idea that Opportunity's last transmission was "My battery is low and it's getting dark." Of course, that would be a human interpretation of some sort of ...
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### How to implement a relative motion STM without any numerical integration

I am trying to program the Gim-Alfriend state transition matrix. You can read all about it here. The GA STM is a complex analytical model that maps relative motion of a deputy satellite in a ...
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### What would the full hypothetical Mars terraforming roadmap look like?

Most of all the articles about Mars terraforming focuses on warming the atmosphere. 2nd most popular topic as far as I know is the magnetic field that Mars lacks. Some other sources speak about toxic ...
44 views

### Is any feature of the Moon protected?

Perhaps this seems trivial, since it may not directly affect our planet, but if we ever colonize the Moon and mine its resources, the trace of human devastation will change sooner or later the surface ...
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### Fate of human-made objects on mars

Now that Opportunity is dead, and since there are ideas for future human missions to Mars, I wonder if there is a project to collect all our rovers and landers or at least label as historical sites ...
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### Why is Angular Momentum of Satellite Rotating in ECI Frame?

Summary: The angular momentum per unit mass of satellite is rotating in ECI x-y plane and I can't understand why. I'm very new to orbital mechanics. What I'm doing: I'm taking the cross product of ...
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### What physical proof that astronauts can live on the space station [duplicate]

I have never seen more than 15 seconds of continuous video of somebody in a weightless state inside of the space station. The vomit comet, an airplane that can fly a hyperbolic dive to recreate ...
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### Looking for veterans of the Space Race [on hold]

Hi everyone. I am writing an oral history of the men and women who worked at Cape Canaveral and KSC during Mercury, Gemini and Apollo. If you know someone that fits the bill, or know how to find them, ...
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### smartphone-grade gnss antennas that makes for poor multipath supression [on hold]

what is it specifically about smartphone-grade gnss antennas that makes for poor multipath supression thus far i have found that it recives signlas differently but i do not understand the wording. ...
39 views

### Age of empires way to terraform a planet? [on hold]

What would it take to send a group of machines to a planet/natural satellite to terraform it, so that they build structures for humans which we can go and reside on ? The group would consist a '...
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### What will happen to space machines if Earth is destroyed?

What will happen to rovers, satellites, and probes if Earth is destroyed? What will their behaviour be like? How long will they keep functioning? Do they have any programmed actions to take in case of ...
19 views

### Can artificial gravity be created by spinning the hull of the space station? [duplicate]

Is it possible to create artificial gravity in space stations by spinning the hull of the same as shown in movies like interstellar and The martian? If yes, at what angular velocity should they be ...
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### What are NASA's dozen payloads for the Moon that will be ready for launch by the end this year? (2019)

Ars Technicha's NASA emphasizing “speed” in its return to the Moon says: The leader of NASA's scientific programs, Thomas Zurbuchen, said this program was designed with speed in mind, and it would ...
5k views

### Why do most space probes survive for far longer than they were designed for?

Looking back to Opportunity (Rest In Peace, little friend), it was apparently designed to operate for 90 days but it ended up going for 16 years which is approximately 64 times longer than the ...
101 views

### Why is NASA buying expensive rockets from ULA when SpaceX is offering the same thing for almost half the price?

Source: https://www.teslarati.com/spacex-ula-nasa-launch-contract-win-vastly-overpriced-official-protest/ SpaceX has filed an official protest with the US Government Accountability Office (GAO) ...
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### Where are all the space capsules? [duplicate]

My understanding is that space capsules, at least until recently with the private companies, have been single-use. Including the Soyuz capsules that Russia keeps using. Which means there could ...
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### Lunar ascent module: thrust and accuracy [duplicate]

I was wondering if there was an optimal law for the thrust (magnitude and direction) during the lunar ascent. From the videos I saw that for the first 10 seconds is vertical but the magnitude is ...
104 views

### When reading “the writing on the wall” in the ISS, which way is up?

This answer to the question Is there really no difference between up and down in ISS? says: ISS does have a sort of 'up and down', deliberately created as part of the design. All the modules ...
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### Relationship between propellant mass and thrust at relativistic speeds

When answering this question about relativity and delta-V I realized I don't know the relationship between the mass of propellants and how much delta-v they would produce in an engine at relativistic ...
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### Delta-V to accelerate to/decelerate from .5c

I have a reasonably good understanding of delta-V (from playing KSP). However, I don't have a great understanding of how it works once you start running into the limitations of physics. I know that ...
43 views

### Does NASA accepts and hire those who have the certification of attestation? [duplicate]

My teacher told me that if I get the certification of attestation, theb he can get hired freely as: Ecologist. environmental protection inspector. After you have studied in Analitic Chemistry. ...
121 views

### How would you eject an object from an airlock for maximum velocity? [on hold]

If a space explorer needed to eject an inert object from a cylindrical airlock that was roughly barrel shaped (length >> diameter) at maximum velocity, would they be better suited to position the ...
217 views

### Is there any chance that Opportunity might still recover from the dust storm?

So, with today's announcement, Opportunity was basically declared dead When the dust storm originally engulfed Opportunity last year, mission scientists were hopeful that they might yet recover the ...
94 views

### How many non-crewed deep-space destinations have had intentional broadcasts of music from Earth?

@Ingolifs's answer to the question What was the last message to Opportunity today (13 Feb '19)? quotes ArsTechnica's Opportunity did not answer NASA’s final call, and it’s now lost to us: Late ...
203 views

### How did NASA's Deep Space Network encode and broadcast music to Opportunity?

@Ingolifs's answer to the question What was the last message to Opportunity today (13 Feb '19)? quotes ArsTechnica's Opportunity did not answer NASA’s final call, and it’s now lost to us: Late ...
4k views

### What was the last message to Opportunity today (13 Feb '19)?

Several articles have mentioned that the last ever commands were sent to the unresponsive Opportunity rover today by NASA. Now, I know that it wasn't a verbal message, but was there anything digital ...
4k views

### What happened to Apollo 13 LM descent stage?

I see in the accounts of the Apollo 13 mission that the descent stage engine of the LM were used to propel the joined spacecraft into a return trajectory to earth and that the crew remained in the LM ...
280 views

### Will SpaceX vehicles orbit Mars before they enter the atmosphere?

When SpaceX starts sending vehicles to Mars, how will they handle landing on Mars? Will the Starship (Upper Stage, transit vehicle) slow down enough to capture into orbit of Mars before entering the ...
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### How much is the difference of gravity attraction between the highest and lowest point on Mars?

Mars has a very high mountain, wich is the Olympus Mons measuring 25 km; while Hellas Planitia is a 9 km deep crater. How much the weight of a man that on Earth is 100kg, change between the highest ...
108 views

### How much does Six Sigma relate to space exploration?

Six Sigma allows industrial quality control at 99.99966% that is if you have some repeated processes you improve until you have a guarantee that only 0,00034% of all processes fail. A six sigma ...
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### Orion Exploration Mission-1; clarification and additional trajectory information?

This September 2017 video NASA | Exploration Mission-1 – Pushing Farther Into Deep Space is over a year old. I found some aspects interesting and wonder if more details about this trajectory are now ...
135 views

### What's the shiny triangular feature on this Progress vehicle?

Picture from here What's the shiny, slightly curved triangular plate with rails above it? A larger version, cropped from here, thanks to a comment by ohsin.
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### How do you calculate the lat and lon of a point on the earth using azimuth and elevation seen from a geostationary satellite?

I am given the longitude of a geostationary satellite and a pointing vector from the satellite in the form of azimuth and elevation angles looking from the satellite towards the earth (where zero ...
3k views

### Qualitative differences between gravity and a spinning habitat

I'm aware that living in a spinning habitat has a couple of noticeable differences from being on terra firma. For instance, running in the direction of the spin ought to make you feel heavier, while ...
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### What is the effect of a solar flare on electronics on the surface of Mars?

Mars has practically no magnetosphere. Where does the impact of a solar flare on the electronics of Mars landers and rovers fall along the scale of nothing to EMP?
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### Would be some sort of cloud software required in a space colony? [on hold]

This is very hypothetical but still hard and not vague theoretic question I think: would future space colonies use some sort of network and hardware virtualization?
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### Why latest Landsat satellites have solar panel on only one side?

It is normal for satellites to have solar panels on both sides of the body. But Landsat satellites, from Landsat 4, seems to have the solar panel on only one side. Are there any specific advantages ...
118 views

### What's the role of the chainmail and scale armor on InSight's WTS?

It's like taken directly from a medieval armor... The role of wind and thermal shield (WTS) deployed over the seismometer is in its name - protecting it from noise and thermal changes. This is fairly ...
191 views

### Why do the ISS' Thermal Rotary Radiators need to tilt?

This answer shows the first image below of a vintage view of the ISS. Only one of each triplet of thermal radiators is extended from each TRRJ. The ISS' solar panels articulate to modulate the ...
82 views

### What was the most recent launch of a nuclear reactor, and what are the current barriers to launching the next one?

This question about Kilopower nuclear reactors got me thinking. Answer(s) to How many nuclear fission reactors have been launched into space? How many are still there? suggest that most nuclear ...
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### What happened to Kilopower generators?

Why are we still using solar power for spacecraft? Would it be possible to replace the giant solar arrays and batteries on spacecraft with Kilopower generators?
2k views

### Travel Speed in Space

I have read several questions and answers here concerning achieving speeds beyond the typical deep-space exploration missions. While speed increases near the Sun for example, that can't be applied to ...
120 views

### What is crossrange and downrange for an entry vehicle?

I have been searching the terms online but still can't get a more intuitive understanding. If you could refer me to some website, book or if you could offer me an explanation I would really appreciate ...
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### Examples of both hardware and software GNSS recievers

I am writing an essay titled: Critically evaluate the positional fixing capabilities of current smartphone technologies for real world GIS data collection I am wanting examples of both hardware and ...
49 views

### Heat balance of the ISS: breakdown?

Is there available breakdown of the heat balance of the International Space Station? In particular: How much heat is produced? by direct warming by sun by warming of solar panels (heat for the ...
2k views

### What are these stacked panels on the ISS in this image?

I found this image of the ISS in a folder on my computer. I don't know the exact source but a reverse image search shows it in many different websites. Unfortunately I can't pin down a date. What are ...
35 views

### Can the term “space weather” refer to the environment in deep space, or is it only in reference to Earth's (or another planet's) upper atmosphere?

@OscarLanzi's interesting answer and my comment there led me to read Wikipedia's article Space weather. The article exclusively seems to only talk about effects in Earth's upper atmosphere; the only ...
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### Why did Deep Space 1 use solar concentrators?

@Hobbes' answer mentions that Deep Space 1 used special refractive solar concentrators attached to photovoltaic cells. According to SCARLET: The innovative array uses 720 lenses to focus sunlight ...
### Ratio of low-thrust slow spiral to Hohmann transfer $\Delta V$?
Going from one circular orbit to another, there are tables out there and equations that give the total $\Delta V$ needed for a two or three impulse maneuver scenario. For a very low thrust propulsion ...