# All Questions

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### Why ECEF does not coincide with ECI on January 1, 2000 at 12.00?

I assumed that ECEF frame coincides with ECI frame on January 1, 2000 at 12.00. To see that, on MATLAB, I used the dcmeci2ecef() function as: ...
71 views

### Where and how many RCS thrusters are installed on Starship?

Starship from SpaceX will soon launch. During the 10 km test it used RCS thrusters to flip itself in the right position. On the website it mentions how important it is to use air friction to slow down ...
• 3,765
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### Have any bits of a space mission ever collided with a planet or large moon (not Earth) that was not a target of the mission?

For example, a mission to Mars for which some bit of hardware ended up entering Venus's atmosphere. Has this ever happened, or at least are there projections that it may happen?
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### Approach to Interplanetary Transfers in GMAT

I hope to find a straightforward process for designing interplanetary missions using the General Mission Analysis Tool (GMAT). This would involve calculating the required initial state, timing, and ...
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### How close was the ISS to running out of supplies after the failure of CRS-7?

2014-2015 probably was a scary time to be aboard the ISS, though not for the usual reasons. They were worried about supplies running low, at least somewhat. There was quite the string of bad luck. ...
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### What is the capacity of the various Falcon Heavy configurations to LEO?

As you probably already know, Falcon Heavy has many configurations, going from all boosters and core expended to all boosters and core landing on land. I am wondering what the payload capacity of each ...
59 views

### When chopsticks catch the booster by the grid fins, what is the maximum vertical speed?

How much vertical speed can the grid fins handle before breaking off?
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1 vote
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### Were Rocket Lab’s Electron rocket engines damaged on impact?

Were Rocket Lab’s Electron mission 26 rocket engines damaged on impact? The photo of the recovered Electron Rocket https://arstechnica.com/science/2022/05/rocket-lab-catches-a-1-ton-booster-falling-...
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1 vote
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### Why didn't Electron's first stage go "There and Back Again"?

During the "There and Back Again" mission, it seems to have been caught around the 52:45 mark. Then it also seems like the helicopter dropped it. Was this intentional? If so, why? It seems ...
42 views

### What are the technical differences between AxEMU and xEMU?

On March 15, 2023, Axiom Space sort-of unveiled their lunar spacesuit, based on the NASA xEMU. I say sort-of because apparently, though the Axiom suit is selected for Artemis III, missions following ...
• 6,631
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### How does SpaceX get through regulatory issues so quickly?

"Regulatory" isn't the right word, but I don't know what is. For example, SpaceX seemed to be able to prove to NASA's satisfaction that they were sufficiently safe to use for crewed launches ...
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### What caused the falcon booster landing failure during the CRS-16 mission?

On December 5, 2018 the Falcon 9 booster started spinning during the landing burn, and promptly appears to have soft landed on the ocean. While SpaceX stated that the booster could be reused it never ...
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### Are Falcon Heavy fairings reused?

I heard a lot about SpaceX reusing the fairings from the Falcon 9. Do they/ are they planning to do the same for Falcon Heavy?
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### Why did the June 2016 SpaceX launch run out of propellant?

In other words, why did SpaceX miscalculate how much propellant the booster needed. They have landed successfully in April. So what went wrong here?
64 views

### How do I make HiPEP [closed]

I'm working on a rocket that uses ESP (electric solid propellant) and I found a propellant called HiPEP which is a mixture of HAN (hydroxylamine nitrate) and Polyvinyl Alcohol. My problem is that I ...
53 views

### An expanding rocket engine nozzle [duplicate]

I know that the efficiency of a rocket engine depends on ambient pressure and nozzle exit pressure. What if there was an engine that had a contracting nozzle? Is that issue such a big problem that it ...
1 vote
59 views

### What is the relationship between the power supply system and the thermal control system?

According to Wikipedia, the solar panels of the ISS produce an average of about 120 kW of electrical energy, which is then used by the station's systems. Can it be converted into something other than ...
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134 views

### Could an ICBM self-destruct? [closed]

A nuclear country's leadership sends a command to launch an ICBM. It launches. Is it ever possible to abort attack on designated target if they change their mind? If yes, for how long? Is it only ...
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### Would it make sense to compress air around a bell nozzle during booster ascent?

Regarding boosters having one single liquid fuel engine, such as Delta 4 for example. Would some sort of annular aerodynamic device, attached to the skirt and placed around the bell nozzle, help ...
• 3,896
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### How many printed novels have been in space to date?

I am talking about actual novels brought for recreational purposes. As in manuals don't count. Also, I would like to know who and on what mission these were brought.
162 views

### Does a RTLS (Return to Launch Site) landing deposit more soot on the booster than a landing on a drone ship?

First, it performs an extra burn (the boostback burn). Does this burn make a credible source of extra soot? Second, sometimes it appears to have flown through the second stage's exhaust plume. Does ...
115 views

### Has Spacex released any reports describing how they are going to secure the payload on Starship?

SpaceX has announced that Starship will be able to lift around 100 to 150 tons of cargo into Leo. When the spacecraft is landing or taking off you don’t want the payload just floating insecurely in a ...
• 3,765
71 views

### Is the net electric charge of Venus about 0.01 Coulombs?

A few years ago Venus was measured to be at a surprisingly large electric potential of $\Phi_{Venus}=+10.6$ volts, which may be one of the reasons Venus lost its water. Does this mean that Venus has a ...
• 197
705 views

### How close do gravitational 2-body hierarchy levels get?

Due to very few 3-body arrangements being stable (this question thus excluding co-orbital objects like trojans), objects in space usually arrange themselves in a hierarchy of 2-body systems. When the ...
93 views

### Establish if Payload is Still Operational - Space Track

The Space Track APIs give great information about satellites that are currently in orbit. However, I'd like to be able to distinguish between payloads that are still in orbit, but dead, and payloads ...
219 views

### Is it possible to create an analytical ephemeris from raw position and velocity of a Body?

I would like to have an analytical ephemeris for various bodies of the solar system (planets, natural satellites and asteroid). I have at my disposition spice kernels from which i can extract position ...
114 views

### Why did the maiden flight of H3 fail?

Recently, JAXA (Japan Aerospace Exploration Agency) finally launched the ALOS-3 (Advanced Land Observing Satellite-3) after more than 2 years of delay. On then all seemed to be going well on the first ...
37 views

### STK: How to create an access report between an antenna and moon? [closed]

I am looking at how to go about designing an access/visibility report between a ground stations on Earth and the moon. I would like to have the coverage run for a couple of years and outline on the ...
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182 views

### Papers/studies about shedding aerodynamic lifting surfaces with booster

(This post has been updated to fulfil community guidelines on specificity) Here's my relevant scenario: A lifting-body Orbital Vehicle, and a turboramjet booster that (the most important part) ...
144 views

### Why was the LES on Apollo white?

In below images they’re red for Mercury (both on the Redstone and Atlas boosters). But the Apollo ones are white. Why were the Launch Escape Systems of Apollo white?
125 views

### Why "The Gateway" could not use Circumlunar trajectory? [duplicate]

My question should have being: "Is it possible to have a stable (minimal Delta-V) Circumlunar trajectory that goes around Earth and the Moon? " Circumlunar free return trajectory Lunar ...
55 views

### How does one use the SEAESRT charging hazard graphic that NOAA provides?

NOAA provides a dashboard for satellite operators. One of the tiles provided is the Charging Hazard graphic included below: I'm not quite sure how is this infographic used? How do satellite operators ...
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### How did theorists determine that the atmosphere attenuates enough to support unpowered orbits?

Before getting rockets into space were scientists certain that the density of the earth's atmosphere would decrease with height enough to permit low earth orbits? If so how was that determined? (If ...
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### Are there any sources with high-confidence state vectors for GRAIL-A?

I have been experimenting with propagation of Moon-orbiting satellites. In particular, of GRAIL-A. In order to obtain state vectors to use as starting points for my propagation, and to compare the ...
• 1,576
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### Could a “solar gravitational synchrotron ” use solar thermal rockets to "powerslide" spacecraft out of the solar system?

Could a “solar gravitational synchrotron ” use solar thermal steam rockets to launch spacecraft out of the solar system? Solar thermal steam rockets https://en.wikipedia.org/wiki/Steam_rocket have ...
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### Sending a Soyuz ship interplanetary - a plausible option?

This is my first time on Space Exploration SE, although I have participated quite a bit over on Worldbuilding. Anyway, as an avid sci-fi reader, I have been wondering if sending a Soyuz interplanetary ...
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### How is this estimation so off?

Based on the recent NASA's DART mission, I wrote some code to calculate the satellite's distance and relative velocity based on the the size of Dismorphos (the target asteroid) on the camera frame. ...
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3k views

### Google maps for Space exploration

Google Maps Can Google Maps for Space Exploration be defined similar to our planet Earth? I.e Planet Mars exploration, Moon exploration, International Space Station (ISS) journey and other planets of ...
1 vote
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### Were the distances traversed by Perseverance on Sol 718 and 719 each exactly 415.27 m or were they added together 415.27 m and if so, why?

The image above is an annotated screenshot of a part of the Perseverance location map. On the location map the white line represents the trajectory that Perseverance has traveled in Jezero crater. ...
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### Negative elevation angle

What does it mean to have negative values of elevation angle from the low-Earth orbiting (LEO) satellite? Can the negative values of elevation angle be useful?
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### Can Martian regolith be easily melted with microwaves?

Apparently, Lunar regolith will melt if you expose it to moderate power microwave energy. Based on the accepted answer to the referenced question, it has to do with the presence of iron in the ...
• 1,053
243 views

### Can Solid Rockets (Aluminum-Ice) have an advantage when designing light space-tug for LEO?

This is a new subject for Space Industry – heavy spacecraft (1200-ton) in LEO that have to burn hundreds of tons of propellant to get going to their destination. It looks inefficient to launch 7+ fuel ...
136 views

### How can you find out how many times a SpaceX fairing has been reused?

For the past few years, SpaceX has been reusing there fairings. While on some SpaceX webcasts they tell you, others they dont. Is there a way to find out how many times judging from how they appear? ...
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### What is pictured in this SHERLOC camera?

This picture was taken by one of the cameras on the Perseverance rover. What is pictured here ? And what is the purpose of this image?
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### Why will Artemis II not orbit the Moon?

The Artemis II mission will loiter in an elliptical, high-Earth orbit before the Orion uses its own propulsion to complete the trans lunar injection (tli), thus using the fuel it might’ve otherwise ...
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### Why does the ICPS carry extra hydrogen?

The Interim Cryogenic Propulsion Stage (ICPS) of the Space Launch System is essentially the Delta Cryogenic Second Stage (DCSS) lifted from the Delta IV rocket. However, among other minor changes, the ...
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### Why do the Falcon 9 fairings have soot on them?

On nearly every SpaceX webcast since 2020 they explain that the Falcon 9 booster has soot on it because, during the entry burn, it flies through its own exhaust plume very quickly depositing the ...
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### SpaceX Super Heavy booster: Is it publicly known whether the failure of one engine to start prior to liftoff will result in a pad abort?

Elon Musk, SpaceX’s founder and CEO, tweeted minutes later that engineers turned off one of the booster’s 33 engines just before ignition, and another engine “stopped itself.” “So 31 engines fired ...
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### Would the reflected sun's radiation melt ice in LEO?

If they tow a big chunk of ice to LEO, shielding from the Sun will be required. My question is, would they have to shield from Earth as well?
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