All Questions

4
votes
2answers
117 views

Have there been any orbital access provided by hybrid rockets?

As far as I know, Hybrid rocketry is limited to suborbital flights and amateur rocketry. I would like to know if there have been any rockets that made it into orbit, and what was the highest altitude ...
3
votes
1answer
81 views

Is the Standard Model of Atmosphere the same as NRLMSISE-00?

I keep reading about the standard atmosphere being a static model and related to the 1976 US standard model. The NRLMSISE seems like an atmospheric model, but I'm unsure if its an extension of the ...
3
votes
2answers
129 views

Sources of Xenon or other noble gases in space?

Xenon is a common choice for ion thrusters, though other heavy noble gases could work due to their low ionization potentials. I got thinking about building or refilling future space travel ion ...
5
votes
1answer
167 views

Could Mars ocean still be there?

So it’s pretty much agreed that Mars was once a wet planet, and most of the water was lost to space. However, I am unable to see why that is necessarily the case primarily for the same reason that ...
6
votes
3answers
216 views

How do orbital spacecraft calculate reentry?

For a given spacecraft, in a given LEO orbit, assuming you have all the required data, how do you choose the needed burnout speed and timing (or position in orbit), in order to reach a certain point ...
4
votes
1answer
127 views

Slide rope way from launch pad of space shuttle?

In the MIT OCW of Aerospace System Engineering lecture 14 at 37:40, Prof Jeffery Hoffman talks about ropeway from space shuttle that goes to a bunker and then they have to ride a military tank ! I ...
12
votes
1answer
1k views

Why does Starman/Roadster have radial acceleration?

Discussion in chat pointed out that the SpaceX Roadster or Starman has a Marsden A1 coefficient. From solution 10 in Horizons: ...
7
votes
0answers
191 views

Why ISS Astronauts have red stripes?

After seeing the interesting question How do ISS astronauts “get their stripes”?, I was wondering why the color red was chosen for the identifying stripe: I am assuming that red is the best color ...
5
votes
0answers
87 views

Probing gas giant planets by descending through a cyclones's “eye”?

On Earth cyclones have regions of calm weather commonly known as eyes. They appear to create tunnels spreading from the top of the atmosphere down to the sea level. Wikipedia article mentions their ...
2
votes
0answers
144 views

why do astronauts in the ISS still use wired microphones?

While I watched the DM-1 hatch opening, I noticed that astronauts use the wired microphone to talk to Huston. It was particularly strange seeing that even because during hatch opening, they were ...
33
votes
2answers
7k views

How do ISS astronauts “get their stripes”?

This answer shows two astronauts on a spacewalk outside the ISS. The caption reads: Rick Mastracchio as EV1 (red stripes) and Mike Hopkins as EV2 (no stripes) leaving the airlock during US EVA-24 (...
1
vote
0answers
48 views

How magnetorquers desaturate reaction wheel? [duplicate]

I am looking for a solution to solve problem of reaction wheel saturation. I am going to use magnetorquers as actuator for desaturation. Any one who can guide me in this respect?
21
votes
1answer
4k views

What are these green text/line displays shown during the livestream of Crew Dragon's approach to dock with the ISS?

During the livestream of Crew Dragon's approach to docking, at 6:24 a laptop display is shown with lots of green text and a camera view of the International Space Station. What's going on?
2
votes
1answer
73 views

How do you determine the orbit of a satellite around some planet of unknown mass?

I am working on project where I want to derive the orbital equation for a satellite of Mass M, orbiting around a planet of Mass P. I want to do this with these unknowns first to then apply the orbital ...
-1
votes
1answer
95 views

How are 9 Merlin 1D engines packed and able to fit in a Falcon 9 FT first stage?

It was proved by Pirl in 1969 the most optimal packing of 9 circles in a larger one https://en.wikipedia.org/wiki/Circle_packing_in_a_circle. The radius of the larger circle should be ≈ 3.613r (r is ...
11
votes
1answer
1k views

What is Crew Dragon approaching in this picture?

Crew Dragon (without a crew) just docked to the ISS for the first time last night. Most of the news reports on it are using the below photo. I thought it was supposed to dock to the Harmony module's ...
4
votes
2answers
73 views

Capture protons from solar wind

Could it be possible ( using a reasonable amount of energy and ressources ) to capture protons from solar wind on (ex. the moon) in order to produce water for a long term self-sufficient mission. The ...
2
votes
0answers
52 views

Among Quantitative Feedback Theory and H infinity, which one is preferred for robust control of satellites esp. small satellites? And why?

I am interested in designing a robust controller for a small satellite with antenna, sloshing propellant and flexible panels on board. I am mostly interested in achieving arcsec precision pointing ...
4
votes
3answers
345 views

Walking in a rotating spacecraft and Newton's 3rd Law of Motion

I am wondering how Newton's 3rd Law of Motion would apply in the case of a man walking the length of a rotating spacecraft. Please reference the drawing below. Say that there was a spacecraft ...
10
votes
3answers
1k views

Can the SpaceX Dragon 2 crew vehicle still use the draco and super draco thrusters to slow down when landing?

In an emergency, is it possible to use the draco and super draco thrusters alone to slow down the vehicle after re-entry? Right from the point parachutes are supposed to be released right upto touch ...
2
votes
1answer
20 views

What are the trade-offs to use a radio relay orbiter also as a radar science instrument?

Any landed mission could benefit from having an orbiting radio relay satellite to help enhance its data rate to Earth. For polar landers on for example the Moon or Mercury it would be a necessity. For ...
5
votes
3answers
197 views

What propulsion system would not pollute the surface when landing on a pristine celestial body?

A robotic lander on a science mission, especially to an airless body, would like to avoid disturbing the surface it is landing on with rocket exhausts. MSL Curiosity used a Sky Crane to somewhat ...
0
votes
1answer
40 views

Weight Flow Rate

I read in the book INTRODUCTION TO ROCKET SCIENCE AND ENGINEERING by T.S.T that Rocket Engineers design how big the throat of the nozzle should be based on the Weight Flow Rate. So my question is HOW?
1
vote
0answers
25 views

Orbit class or library or functions [closed]

I am (like a hundred other people, like a thousand other people) trying to make a space flight simulator. I'm not a student. (That said, I found Orbit – space flight sim. It’s excellent.* You ...
8
votes
0answers
231 views

Purpose of side holes on SuperDraco pods of DM-1 flight Dragon 2 capsule

I've watched the launch video for DM-1 today, and one thing caught my attention. On SuperDraco pods, below the plugged SuperDraco engine openings, there are two more plugged holes. I've marked them on ...
3
votes
0answers
84 views

Why did Skylab have a thick blue flexible cord running down its central axis?

After watching the video below (found here and here and here) I am reminded of the series of possibly less than 100% serious questions here about being weightless in the middle of a large volume and ...
2
votes
0answers
55 views

What's the longest time that an astronaut remained in free fall?

After watching the video below (found here and here) I am reminded of the series of possibly less than 100% serious questions here about being weightless in the middle of a large volume and ...
5
votes
0answers
133 views

Did NASA tell the Skylab astronauts to “Stop running around!”?

This answer to the question starts with: This video may help to answer your question. Starting at about 00:24, you can see an astronaut running around the "exercise wheel" of Skylab (an early NASA ...
0
votes
1answer
51 views

Who released pre-launch TLE data for the Space Shuttle?

The question Pre-launch TLEs for NASA launches asks: I was curious if the United States is on the verge of launching maned flights to the ISS, will anyone release Pre-Launch TLE data like was done ...
1
vote
1answer
51 views

How are airborne particulates monitored on the ISS? Are they distinguished at all by size and/or type?

The question What kinds of activities, experiment and, procedures done on the ISS must be done in chambers vented to space? links to and quotes from this answer to the 3D Printing SE question How is ...
0
votes
0answers
21 views

What kinds of activities, experiment and, procedures done on the ISS must be done in chambers vented to space?

This answer to the question in 3D Printing SE How is 3D printing done in space? says The first big space-specific issue is actually air quality. You can't just open a window to air out the molten-...
1
vote
0answers
51 views

Was there a thunderstorm in Florida during the Crew Dragon Demo 1 launch?

The video from SpaceX this morning shows a number of red flashes in the sky at T-00:20:34, T-00:09:36, T-00:04:50 and T-00:02:15. The most noticeable was at T-00:04:50. These flashes look like ...
5
votes
1answer
90 views

Does exploration of Venus' atmosphere now require any planetary protection protocols?

This answer quotes Marc Rayman's August 21, 2018 Dawn Journal entry: Not all solar system bodies need such protection. The Moon, Mercury and Venus, for example, have not been of interest for ...
4
votes
1answer
42 views

Mechanics of Sun-Synchronous Orbit & North Korea's KMS-4

QUICK QUESTION: Is North Korea's KMS-4 in a proper Sun-synchronous orbit? https://www.n2yo.com/?s=41332 2016-009A FOLLOW-UP QUESTION: How do I tell? I want to understand the mechanics. RESEARCH:...
6
votes
1answer
128 views

Have the rovers on Mars encountered anything unrecognizable to geologists?

We have quite a few rovers trundling around Mars. Just from reading the popular news, I get the impression that everything encountered so far (minerals, rocks, strata, formations, structures, etc.) ...
3
votes
0answers
40 views

Pre-launch TLEs for NASA launches

I was curious if the United States is on the verge of launching maned flights to the ISS, will anyone release Pre-Launch TLE data like was done back when the shuttle was flying.
2
votes
1answer
110 views

Why don't SpaceIL's Beresheet spacecraft and Moon orbits line up?

The question Tracking SpaceIL Beresheet Moon lander links to some data files that are from the site: http://live.spaceil.com Raw data: http://live.spaceil.com/data/data_s1.txt (22/2 - 12/4) ...
1
vote
1answer
38 views

Pressure effect during atmospheric entry

Maybe this question has a very obvious answer (I'm no aero engineer though), but I'll appreciate the clarification! So, I was reading an old nasa paper that indicates that the dynamic pressure for ...
2
votes
2answers
200 views

Tracking SpaceIL Beresheet Moon lander

Does anybody know if Beresheet orbital data are available on NASA Horizons? Some bodies are listed by reference number, with no name: https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&...
1
vote
1answer
26 views

What is VBB recentering (InSight lander's Very Broad Band seismic pendulums)?

From the Planetary Society Blogpost InSight Update, sols 25-42: Seismometer sensors working! Tricky setup and cable management on Mars This is an animated GIF: It's fairly subtle, you may not notice ...
1
vote
1answer
86 views

Conditions on Titan under which human breath can be set to fire

Motivated by the question Titan vs Mars for colonization, I wonder what exactly happens if human exhalation products are released into Titanian atmosphere and, say, a spark igniter happens to be ...
0
votes
1answer
74 views

How is the atmosphere in the pressurized housing of ISS' HDEV cameras managed? Outgassing addressed?

This answer says: The ISS live feed uses the cameras of the HDEV experiment. This is a group of four cameras in a pressurized housing attached to the outside of the ISS. A hermetically sealed ...
3
votes
3answers
110 views

“Hybrid” ion engines?

If it's possible, could you use "hybrid" ion engines, maybe VASIMR, running on a mix of hydrogen, argon, and oxygen to exceed the velocities produced by any other ion engine? Could buckyballs also be ...
5
votes
3answers
117 views

Are sun-synchronous orbits always North to South?

So someone told me that weather satellites orbit from north to south generally because that helps them to obtain a sun-synchronous orbit (his explanation for why this was true was too complicated for ...
1
vote
2answers
135 views

Titan vs Mars for colonization

This question is along the same vein as Venus vs Mars for colonization but without the person at the table. Is Mars better than Titan which to me seems a more realistic option for colonization? With ...
2
votes
1answer
42 views

Molecular propellant in ion engines

This question was prompted by discussions on this question. Can there be an advantage to using a molecular propellant in an ion engine, as opposed to noble gasses or iodine? (Although iodine actually ...
1
vote
1answer
71 views

Identifying some sort of flare near Earth

Anyone know what this flare is in the top lefthand corner of the picture? The image was captured from the ISS live feed app for android 28/02/2019 at 18:38 BST
2
votes
1answer
54 views

Stabilization of Lagrange point asteroids

There are a couple discovered asteroids that orbit around L4 or L5 Sun-Earth Lagrange points https://en.wikipedia.org/wiki/(419624)_2010_SO16 https://en.wikipedia.org/wiki/2010_TK7 From what I read ...
2
votes
0answers
56 views

What are the questions and issues related to Kosmos 482's configuration and eventual reentry?

The Space.com article Failed 1970s Venus Probe Could Crash to Earth This Year describes Kosmos 482 (1972-023A, 5919), a 1972 Soviet Venus lander spacecraft that got stuck in LEO instead. Since the ...
1
vote
0answers
54 views

Are SpaceX subject to “Common Carrier” provisions from the FAA, NASA or others? [duplicate]

For instance, could SpaceX refuse to carry OneWeb satellites because it is a competitor to StarLink. Obviously SpaceX shouild be able refuse payloads as incompatible with their vehicle. The obvious ...

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