# All Questions

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### Mercury reentry heat shields; material composition, manufacturing process and explanation of all those concentric ridges?

A collection of photos in posts by Miles Lumbard there is a page titled Mercury Retro Pack Walk Around Page 1 (spotted here in reference to the thermal zebra stripes) can be found nine images with the ...
30 views

### Orbital Insertion Altitude for Rendevous with ISS

When SpaceX launches a CRS mission to the ISS, what altitude do they target at orbital insertion? If the ISS is 400 km above ground, do they target 400 km at SECO? Or do they target a lower number---...
22 views

### How does one go about naming a lunar crater? [migrated]

Suppose I discover an uncatalogued crater on the lunar surface, and decide to name it. How would I submit my proposed name to the IAU?
32 views

### Avoiding Martian contamination with Earth microbes

Unmanned probes can be sterilized, but when humans begin occupying Mars in large quantities, how can contamination of possible Martian microbes with Earth microbes be avoided?
96 views

### Cryogenic storage in Starship header tanks

Since Starship uses cold liquid oxygen and methane fuel in its header tanks, how will these cryogenic tanks been kept full and cold on long missions in space?
182 views

### How to make a model rocket that doesn't spin?

I'm attempting to build a rocket with 8 fins (four on bottom and four smaller ones towards the top). The four fins near to the top will be attached to servo motors and programmed to stabilize or guide ...
216 views

### Can the Space Shuttle land on Mars assuming there is a paved surface for landing?

Can the Space Shuttle land on Mars if it had a paved runway? Can the Space Shuttle use aerobraking and will its control surfaces provide attitude control? Can the parachute and braking systems stop ...
118 views

### Soviet Luna 16 Spacecraft

Is the Soviet spacecraft Luna 16 still working and transmitting temperature & radiation levels? Attempts to Google the results of Luna 16 have failed, possibly because the results are in Russian.
102 views

### Rocket dashboard: separation/pyro indicators

I'm curious about rocket dashboards. Separation events are big things and they depend on pyro bolts detonating and linear charges or pneumatic pushers firing immediately afterward. There must be ...
62 views

### Has Made in Space any track record growing specialty crystals in microgravity before? (“Industrial Crystal Facility” to fly this year)

Ars Technica's There are an insane amount of cool space things happening in 2021 mentions: This year, Made in Space's "Industrial Crystal Facility" should also fly to space. This will serve ...
96 views

### How can you calculate a course based on constant acceleration burn and deceleration burn?

In the TV series The Expanse, a sci-fi space-engine called the "Epstein Fusion Drive" is a thruster capable of performing constant acceleration (up to and beyond "20g" (about \$200 ...
46 views

### How important is the convergence angle of a liquid bipropellant rocket engine

So I can't exactly find out what angle should the converging part of the rocket chamber be or why different angles are chosen for engines (varies by about 15°). Are there any guidlines on the angle or ...
54 views

### What is more promising: the development of nuclear space tugs (Roskosmos, etc.) or the improvement of existing ones? [closed]

There are a lot of things in space now that require the use of space tugs. Many companies are developing their space tugs. For several years there has been talk of a nuclear space tug. Are all these ...
88 views

### What ever happened to 6Q0B44E - potentially the “artificial satellite (with) the farthest orbit around the Earth”?

I just started flipping through Handbook of Space Engineering Archaeology, and Heritage Space Hardware Ann Darrin & Beth L. O'Leary, Eds. 2009, CRC Press, Boca Raton, 1035 pages It looks as though ...
88 views

### Is there a widespread popular misconception of how expensive it is to launch a cubesat? [closed]

Sometimes one sees discussions about hypothetical CubeSats with impressive abilities that seem to be assume that CubeSats are cheaper to launch (not merely individually, but by mass) than larger ...
76 views

### What are the Basics of CubeSat Power Supplies and Systems?

I am going to go ahead and apologize for my ignorance surrounding this topic, as my background is Aerodynamics, and not Electrical Engineering. From what I understand, CubeSats typically generate ...
68 views

### Surface processes of the valleys on Mars

I have two related questions about geophysical processes related to talus* fans on Mars: How were talus fans on Mars formed? (like Valles Marineris or Kasei Valles) What is the role of these fans or ...
88 views

### Pee processing in space

Do astronauts drink each their own pee or is there a common pee container where all pee get collected and processed? It's clear to me that the obtained water must be sterile, but even then, I imagine ...
129 views

### Gimbal Check: Before or After Engine Ignition?

Is the engine gimbal check done before or after ignition? Also curious: How many seconds does the check take? What does it consist of? Do they gimbal each engine separately, or do they gimbal all ...
6k views

### What was the “5 minute EVA”? What was the shortest-duration EVA ever?

A comment to this answer makes the claim humans are so impaired in space that their ability to repair anything is ridiculously low (hours of preparation and debriefing even for a five-minute EVA, and ...
124 views

### Is space habitation a technology problem or is it really just a mass (cost) problem?

There are a lot of challenges with space habitation. Gravity, radiation, fuel for reactions to maneuver, water, atmosphere, food, etc. etc. NASA and many others are working on all kinds of solutions ...
117 views

### How many sun sensors are required to find a cubesat's orientation

I have read how a sun sensor can help find the orientation of a spacecraft, but I wasn’t sure how many are required, e.g. if one is needed on each face of the Cubesat. (Any additional information is ...
30 views

### If I know the masses, positions, and velocities of two objects, how do I calculate their trajectories under gravity?

I was thinking about the effect of a near-miss with an asteroid upon the orbit of the earth around the Sun. My goal is to figure out a formula I could use for a visualization I'd like to build to get ...
44 views

### Calculating the length of a launch window?

May somebody guide me what exactly determines the length of a launch window? When doing the (basic) celestrial mechanics caclulations for e.g. a transit from Earth to Venus, one usually assumes point-...
28 views

### Does the displacement angle change after burnout?

I came across the above image on Nakka's page about fins and what I understood is that rockets will turn into the wind during the thrust phase, and will drift slightly with the wind after burnout. But ...
65 views

### Satellites Orbital Parameters

I want to access satellites' orbital parameters like inclination, right ascension of ascending node and argument of perigee. Unfortunately, I haven't been able to find this information. Is there a ...
165 views

### Bucket loop between Earth and Moon?

Please don't bite my head off. If this is so stupid that it deserves to be squashed, I'm quite happy to delete the question. I mainly would like to know whether anyone's ever suggested this (I ...
18 views

### How many cubesat U's is CAPSTONE really?

Wikipedia sez: The orbiter is a 12-unit CubeSat but looking at the images in the new NASA video NASA 2021: Let's Go to the Moon I see artwork that shows Capstone as a square-based prism with the ...
84 views

### Besides landing several folks on the Moon and returning them safely to the Earth what criteria did Human Landing System proposals to NASA meet?

The new NASA video NASA 2021: Let's Go to the Moon shows artwork for three very different spacecraft sitting on the lunar surface with the overlain caption Selecting A Human Landing System "...
64 views

### Technological challenges to sending a high altitude balloon to space and orbit from 50 km?

Below At what altitude would I have to go in a lighter than air balloon to be above all wind and just have the earth rotate underneath me? there is a comment: If you want to be above all winds, you ...
112 views

### Was the nature of Explorer 3's orbit intentional?

A number of early spacecraft launched into orbits other than the intended one. For example, Explorer 1's apogee of 2550 km was much higher than intended, and Vostok 1's was too high to decay in the ...
97 views

### Why are some rockets painted black? [duplicate]

Why are Rocket Lab's and other rockets painted Black? Shouldn't they be painted white to reflect most light and therefore absorb less heat from sunlight?
60 views

### How does one determine the optimal CH4:O2 ratio in a methane-LOX rocket engine?

The SpaceX Raptor uses a 78:22 O2:CH4 ratio. It also has combustion chamber pressures higher than any other rocket engine ever built. My questions are: What's the math / chemistry that determines ...
2k views

### Using a fidget spinner to rotate in outer space

There is a question How do astronauts turn in space?, and related questions here and on physics.stackexchange, that detail how astronauts might maneuver by spinning their upper and lower body ...
134 views

### Is it really possible to catch the Super heavy booster by using the launch tower ? How Challenging will it be?

Reports say that SpaceX now aims to recover the Super heavy booster by catching it with the help of the launch tower. What are the engineering challenges for this and how will it benefit ? News ...
81 views

### Average acceleration of a rocket given average mass and thrust

If we assume that a small scale rocket is launched perpendicularly to the ground and ignore the drag, how can I calculate the average acceleration given that I know the burn time, the average thrust, ...
26 views

### Direction of heliocentric entry velocity for fly-by coming from interplanetary Hohmann transfer?

I'm following Curtis's equation on interplanetary transfers. I'm confused by the direction of the entry Heliocentric velocity for a fly-by. If the assumptions is that orbits are: Coplanar, cofocal ...
140 views

### Is the SETI's needle-sharp at 982.002 megahertz signal accessible? [migrated]

In April-May 2019, the Parkes radio telescope, in Australia, received a weird signal while surveying Proxima Centauri. Is this signal available, ideally in some digitalized form? Where could I ...
3k views

### Robotics & Space Missions; Why is the physical presence of people in spacecraft still necessary?

Robotics is now well developed. Many programming languages allow you to work in real-time. Also, a new era of space missions and research is in full swing. So here's the question: Why is the physical ...
96 views

### How many Soviet space missions have had at least one tortoise?

Science Alert's These Are 7 of The Strangest Experiments Humans Have Ever Done in Space talks about two tortoises that flew aboard Zond-5 spacecraft on 2 September 1968, then later goes on to say: We'...
44 views

Does the payload capacity of a rocket include the satellite and the adaptator or is it just the satellite ?
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### Number of nonhuman primates dead in space exploration

This statue, "Sam", in Riga, Latvia, is dedicated to the animal cosmonauts who perished during space flight experiments. As far as I know, there were a lot of dead dogs on space flights, ...
82 views

### JAXA/NASA astronauts on a Shuttle mission; was it like dual citizenship/joint appointment or did one agency take precedent?

Professor and former astronaut Takao Doi does many things, including being a Space Shuttle mission specialist, an amateur astronomer and discoverer of two supernovae 2002gw IN NGC 922 and Supernova ...
42 views

### Do black holes emit enough heat to heat a planet? [closed]

Under what circumstances can a blackhole emit enough heat to allow life on an orbiting planet?
62 views

### Can Starship use dedicated smaller auxiliary landing fuel tanks?

Would it be better for Starship to have a separate set of small fuel tanks dedicated to landing the ship, maybe controlled separately or plumbed differently.
78 views

### How many times is a single rocket engine tested?

When a rocket engine is loaded into a test stand is it tested once before removal or is it allowed to cool and then tested again. Is every liquid-fueled rocket motor that flies to space first tested ...
21 views

### Did Starlink's experimental Darksat help reduce brightness? [duplicate]

Did Darksat's visor like coverings to its parabolic antennas reduce the brightness or was it a failure. Or is SpaceX devoleping any other mechanisms or manuveres to counter this problem?
167 views

### How many time-zone does the ISS cross through during one orbit?

A recent non-answer to an unrelated question stated that the ISS crosses 16 time zones during New Year's Eve, which is obviously incorrect, the actual answer being "around 200". But this ...