# All Questions

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I am a beginner in the field of aerospace. Recently, I wanted to use the extended Kalman filter to improve the orbit. My idea is to use TLE data as observations values, the ...
2k views

### How can Artemis 1 take so much longer for Earth-Lunar transit than the Apollo missions did?

The Artemis I mission will take 8-14 days to get from Earth to the Moon. Apollo 11 only took 3 days. Similarly the return will be 9-19 days for Artemis I and just over 2 days for Apollo 11. Why is the ...
1 vote
749 views

### What is the best fuel for bottle rocket? [closed]

I want to modify my firework bottle rocket to fly a mile high. What will be the best fuel for this? Could fuel used in space rockets be scaled down to work in a large bottle rocket? I am specifying a ...
40 views

### How to find cost data for commercially available spacecraft components?

I'm trying to research how much it should cost to build a small spacecraft, but it's super hard to find good information on the cost of various components. Can anyone suggest any good resources? For ...
1 vote
76 views

### Satellite position using 2 station ranging

Two Station Ranging Given the position of 2 stations and the distance between both and the satellite (in km, say) and the fact that the orbit is geostationary and positioned at 45.1(degrees) west, ...
1k views

### How does Spinlaunch manage the counterweight right after launch?

Spinlaunch has successfully launched a suborbital test vehicle from a 1/3 scale demonstrator, see for instance aviationweek.com or space.com. While spinning up the arm, perfect balance is achieved ...
117 views

### Why will the next missions to Mars not search for past life where once deep-water hydrothermal vents were?

The iron-sulfur world theory and the deep sea vent hypothesis are among the most popular ones to explain the origin of life on Earth. This article (Michalski J et al. Ancient hydrothermal seafloor ...
246 views

### Images of the DART impact on Asteroid Dimorphos other then DART images

I am looking for DART impact images from others source. Images which came from some telescopes etc. Where I can find it? Sorry for My English.
29 views

### Dilution of precision in different coordinates

Given the ranges $\rho^{(s)}_{R_x}=\sqrt{(x_{R_x}-X^{(s)})^2+(y_{R_x}-Y^{(s)})^2+(z_{R_x}-Z^{(s)})^2}$ between a receiver $R_x$ and an $s$-th satellite, where $s=1, 2, ... n$, one can construct the ...
68 views

### How to calculate the ECEF coordinates of a satellite given its elevation and azimuth angle, plus the coordinates of a reference object on Earth

So I am looking for a way to 'reverse engineer' satellite ECEF coordinates given its angles of elevation and azimuth and given the coordinates of an object on Earth serving as a reference ground. The ...
44 views

### Could Bepi-Colombo image the Messenger impact site?

Is the location of the impact site of Messenger known with sufficient detail to image it from low orbit? Does Bepi-Colombo have a high enough camera resolution to image Mercury at whatever the ...
2k views

### When has hydrogen peroxide been used in rocketry?

Peroxide is apparently a very good propellant, but I can't seem to find any instance of it being used. Has it ever been used and if not, why hasn't it? What's its downsides?
401 views

### How (the heck) was coherent synthetic aperture radar (SAR) implemented using photographic emulsion aboard Apollo 17?

This answer to Is there really microfilm on the Moon? includes a block quote which includes the following subquote: The equipment was installed in the service module and consisted of a coherent ...
136 views

### Draper Semianalytical Satellite Theory (DSST) C/C++ version

Anyone knows where one could find the Draper Semianalytical Satellite Theory (DSST) semi-analytical propagator code in C/C++? I know Orekit includes the Java version inside its code. An in general if ...
65 views

### What would the TLE data (Mean Motion, Eccentricity, Inclination, RAAN, Argument of Pericenter) of GEO and PO be like?

I am currently making a satellite tracker app for android. I want to test my orbit propagation algorithm and I want to make some made-up basic orbits, so I need to know how their TLE would be. I want ...
26 views

### Which were the more than 60 (!) candidate locations for the Mars 2020 rover?

Four years ago I asked for the 21 potential landing sites for the Mars 2020 mission in this question, but now I've learned that there were more than 60 candidate locations ! From NASA Announces ...
218 views

### Tory Bruno mentioned "unsolvable combustion instability" of "large methane engines". What, why, how?

Relevant tweet, an hour ago: https://twitter.com/torybruno/status/1405210138189864960?s=19 a Tweeted Question: Why wasn't methane used in the 2000s, when it was readily available unlike the time ...
173 views

### What are the negatives associated with Thrust-augmented Nozzles aka Afterburning Rocket Engines?

An interesting comment here introduced me to the concept of Thrust-augmented Nozzles aka Afterburning Rocket Engines. The pubs I've read on it so far introduce the concept as a way to provide good ...
98 views

### What would have happened if DART failed to hit Didymoon?

So I remember reading that there was a 10% chance DART will not hit Didymoon. It was on the German Wikipedia, but without a source. Now, I'm wondering if there would have been any plans if DART failed ...
290 views

### long sequence of satellites moving west to east?

yesterday (27/3/2020), 20:00, I was on high ground in central switzerland and looked south. in the clear night sky, I saw what I think could have been satellites: linear trajectory, high speed, ...
2k views

### What caused the jitter in the DART video as it approached Dimorphos?

If you look at the series of images DART took as it approached Dimorphos, the asteroid jumps around a bit as you approach. Does this mean small corrections were being made right up till near the end? ...
6k views

### What technological breakthroughs were required to land booster stages?

It is only recently that SpaceX developed first stages that can land again, and be reused. The (until recent) non-existent landing of re-useable rockets is presumably, partially, due to a lack of ...
1 vote
92 views

### What is the propellant consumption rate for Soyuz?

At what rate does a Soyuz propulsion system (KDTU-80) consume it's propellants? I am interested in the mass consumption rate of both the main engine (e.g. an s5.80) and a single DPO thruster. Please ...
524 views

### Could an Apollo Lunar Module have landed and returned without Earth assistance?

From the Apollo 12 flight journal: 087:31:29 Conrad (onboard): [Laughter] Yes. Let's take the LM down and land on the back side. Wouldn't that shake them up? [Laughter]. 087:31:36 Bean (onboard): We ...
148 views

### Orbital Chinese firework-cluster

I remember when I was younger I had heard this story about the Chinese using primitive fireworks, and even strapping them to a bamboo glider in an attempt to reach the moon. This story probably isn't ...
1k views

### Why NASA's sudden renewed (apparently) interest in Wax hybrid engines? Which property is so attractive now?

update: This answer links to Larry Russell Kellogg which links to NASA Tests Environmentally Friendly Rocket Fuel where images of Test firing of new Paraffin-Based Fuel at NASA Ames Research Center 1/...
308 views

### Why was Apollo 17 considered to have "achieved a very successful geological survey"?

They listed out all the apollo missions, with blurbs about what the outcomes were, for example here's 15, 16 and 17: 15 - Landed on moon and deployed lunar rover. 16 - Landed on moon and deployed ...
1 vote
258 views

### Looking for figures for contemporary interstellar engine options

So I have already done... a lot of reading on this subject lately. A lot. You wouldn't believe. My maths is... functional, probably far above 'average', but when it gets into the realms of the 'rocket ...
203 views

### Was it possible for the Chinese to send a rocket using gunpower past the Karman line?

The Chinese invented the first rocket. Their rockets were fireworks using gunpower to fly which usually only flew a few hundred meters. I was wondering if it were possible with the technology of ...
495 views

### Why would a significant non-zero angle of attack be an advantage during 1st stage burn?

From videos of both the SES-10 launch shown in @RussellBorogove's question, Cause of apparent plume deflection on SES-10?" and the Block 5 launch Bangabandhu Satellite-1 Mission at ...
1 vote
39 views

### What will be more important for the first NASA led human mission to Mars, the exploration of important science targets or the mining of water ice?

A few months after NASA's decision in November 2018 that Jezero Crater would be the landing site for the Mars 2020 rover mission, the research article The Geology and Astrobiology of McLaughlin Crater,...
788 views

### Why do the shapes of these two exhaust plumes from an Atlas V 411 look different?

The Atlas V 411 configuration is interesting because there is a single SRB on one side of the first stage, requiring the main engines to vector substantially to keep the thrust mostly axial. The ...
2k views

### How are cryogenic rocket propellants delivered to the launch pad?

I work at a university that gets LN2/LHe (liquid nitrogen and helium) delivered a couple times a week by a large tanker truck outside my office. It seems to work well enough to deliver a couple tons ...
293 views

### How do you mine water on Mars?

Water is required for human explorers of Mars and it is also widely expected to be used to synthesize methane rocket fuel for the return trip (by combining the water with CO2 and energy to create ...
121 views

### Depth to diameter ratio of impact craters

Two questions on this site concern themselves with the depth to diameter ratios of craters: Catalog of lunar crater depths and diameters Where on Mars are there possible other collapse features with ...
38 views

### Pre burner design for cryogenic propellants [closed]

I have to design a preburner to change the phase of my propellants from liquid to gas and they are stored as cryogenics. I have tried to find resources on preburners but none of them specify how to ...
1 vote
71 views

### What are better ways to deliver heat directly to propellant in a Thermal Rocket design for use in launch than UV such as in the Nuclear Lightbulb?

Most advanced, high-power engine concepts that I came across aren’t suited for atmospheric launch, so I got curious about what kinds of engines could launch a very heavy craft from the surface of a ...
33 views

### Would planetary quarantine have to be used for asteroid mining missions?

Currently, sample return missions have to follow very delicate procedures to move the sample to the return vehicle. This is incredibly complicated and may explain why so few missions have launched. ...
150 views
+50

### How to protect Mars/Moon mission crews against meteors?

Humans are expected to return to the Moon (see Artemis) and maybe go to Mars (see this and this) within a decade or two. Meteors frequently strike the surface of both the Moon and Mars (one can't ...
115 views

### Have there been any rockets whose payload fairings consisted of more than two parts?

Most cargo rockets, such as Falcon 9, Delta IV, and many others, incorporate payload fairings to protect payloads from aero forces and heating during ascent. All of these rockets' fairings split in ...
119 views

### Were there backup routes planned for the Apollo LRV?

I just finished reading "A Man on the Moon" by Andrew Chaikin, an amazing read. For the missions involving the Lunar Roving Vehicle (LRV, Apollo 15-17), there are some mentions of astronauts ...
445 views

### What went wrong with Apollo 15 astronaut Al Worden's seat when he was all alone, circularizing?

The X article NASA shock: Apollo 15 astronaut's Moon landing confession - 'Can't do anything to me now' says "NASA astronaut Alfred "Al" Worden dropped an astonishing Apollo 15 ...
84 views

### How do different stages attach to each other?

I started learning about rockets recently, and while searching for information, I found some ways that different stages separate, but I wandered if it was possible that they could reattach to a ...
96 views

### Dimorphos natural orbit variability vs DART impact

As we know, DART spacecraft have impacted Dimorphos, a satellite of Didymos. The impact will change the orbital period. Depending on the properties of Dimorphos (mass, porosity, cohesion), the period ...
37 views

### A hybrid micropropulsion system for CubeSats

I am curious about how much potential would a hybrid (electric & chemical) micropropulsion system have for CubeSats. The chosen propellant is water due to its non toxic nature, cheap cost and high ...
36 views

### How to convert TLE data into state vectors in ITRF?

As shown in the question, Now I have a TLE observation data and CPF(Consolidated Prediction Format) data. According to CPF's documentation, CPF predictions are tabulated satellite state vectors ...
298 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.
87 views

### If the pseudorange is not fixed, how does a receiver lock/fix onto a satellite signal?

If the satellite moves around the orbit at a velocity, the pseudorange between the receiver and the satellite should be changing right? If so, how does a receiver lock onto a satellite signal if the ...
165 views

### Was DART meant to impact dead center?

According to eyes on the solar system, Dimorphos is tidally locked to Didymos. If DART impact direction is perfectly aligned with Dimorphos center of mass, all of the momentum transfers into orbital ...