Questions tagged [design]

Questions about how space vehicles and related hardware are designed. See also [structural-design] and [engine-design].

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Why is there a need for a "forward skirt" segment on SLS solid rockets?

The SLS solid rockets have a "forward skirt segment" above the five true rocket propellent segments. What is the purpose of this segment? I believe that it contains the avionics for the ...
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7 votes
1 answer
288 views

In Apollo hardware, why were sump tanks needed?

I'm looking at the Apollo CSM Propulsion Systems. These were bi-propellant hypergolic systems. However, for some reason each type of propellant was divided into a storage and sump tank. For example, ...
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1 vote
4 answers
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Selecting an optimal Isp / what makes an Isp too high (mostly for high Isp)

When, and why, is it possible to have an Isp (usually of an ion or nuclear engine with Isp far beyond the limits of chemical fuel) that's too high? What makes the Isp too high, and (other things being ...
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18 votes
1 answer
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What are the "disks" seen on the walls of some NASA space shuttles?

I'm deep-dive researching older NASA shuttles, and a few elements in this image of a toilet (which could be found on display at JSC in the early aughts) stood out to me. See the red circles I added to ...
1 vote
0 answers
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Material defects and its testing for manufacturing of parts

Is there any literature report on what is the level of testing at NASA on the defect sizes in raw material for manufacturing of parts for space shuttle and other space vehicles? For example, what is ...
3 votes
2 answers
161 views

How would building rockets on other planets and moons influence their design?

John D. Clark's Ignition! says that a frequent problem with choosing propellants has been that they can be very challenging or dangerous to handle, or that they have a high melting point or a low ...
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2 votes
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Earth to Mars Transfer using GMAT

I saw a couple of people mention here that in order to change the epoch date from the given Mars transfer example on GMAT I would need to change and re-optimize initial conditions. How would I do that?...
5 votes
1 answer
188 views

Why wasn't the wind and thermal shield of Insight's deployable seismometer integrated into the instrument before deployment?

This fascinating question and answer covers how Insight's seismometer was deployed by its robot arm, and how a subsequent robot arm maneuver covered it with a wind and thermal shield. What parts of ...
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Alodine on Spacecraft External Surfaces?

What type of alodine is used for external coatings on satellites, if necessary? Is it type 1 (hex chromate) or type 2? Is there a disadvantage using type 1?
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5 votes
1 answer
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Spinlaunch Safety

How could the Spinlaunch concept ever be made so that, in the event of an anomaly where it is released at the wrong angle, it wouldn't obliterate a small town or city center? Launch sites at Cape ...
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2 answers
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Specifications for Spacecraft interior and exterior paint colours

Are there specifications for Crewed mission spacecrafts in terms of interior and exterior paint colours? I.e. Only specific paint colours are required internally and externally. Can these paint ...
15 votes
1 answer
1k views

Black/White patterns on SLS boosters, fairings - Are these still roll patterns

The main purpose of the large black/white patterns on many of the early rockets was to make it easier to spot whether the rocket is rolling. The pattern on the Saturn V was changed to avoid picking up ...
9 votes
1 answer
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Two-Stage Fully-Reusable Shuttle

In chapter 6 of SP-4221 "The Space Shuttle Decision" they are talking about the fall of the "Two-Stage Fully Reusable Shuttle". In one paragraph they talk about how this Two-Stage ...
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2 votes
0 answers
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Using belt drive in LEO spacecraft?

I am designing a concept for a LEO spacecraft and need to transmit mechanical power (0.5Nm @200rpm rotation) over a distance (1-2ft). Chains or belts would be a natural choice for terrestrial ...
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3 votes
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JWST - coordinates of each of the 18 mirror segments?

I am curious about the relative orientations and locations of each of the JWST’s 18 hexagonal mirrors, when they are in place. The unfortunate (and subsequently corrected) problem with Hubble’s ...
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11 votes
2 answers
338 views

Mystery balls! Gemini apparently had "thousands of hollow ping-pong-sized balls made of extremely thin aluminum embedded within its walls". What?

This fascinating answer says that "The Gemini capsule floated because it had thousands of hollow balls made of extremely thin aluminum, each composed of two half-spheres welded together, the size ...
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8 votes
1 answer
380 views

Why aren't off-axis reflector telescopes more popular for space telescopes? Have there ever been any?

It seems that: The light gathering capabilities would be slightly better without the blocked aperture (clear aperture is a premium for fairing-limited space telescopes) The diffraction patterns from ...
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5 votes
1 answer
149 views

Has Falcon 9 block 5's design stopped evolving?

Spacex famously iteratively improves the design when developing rockets, with each unit being slightly (or not-so-slightly) better than the previous. These days Spacex seems to be focusing most of ...
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1 answer
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Why does Q-SAT look like a buckyball?

Tech.China.Com.cn's August 7, 2020 article Tsinghua University Successfully Launched Gravity and Atmospheric Science Satellite (Chinese, title translated to English) includes the image above of what I ...
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1 vote
0 answers
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What fraction of the Kapton thickness on the ISS' solar panels was likely eroded throughout their lifetime? Predictions? Measurements?

Background @Tristan's answer to How are the silicon PV cells constructed in the ISS's solar panels? Are they as flexible as they appear here? informs us that Kapton is part of the "blanket" ...
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4 votes
1 answer
212 views

How is a desired chamber pressure achieved in a liquid rocket engine

Before everyone responds that this has been asked before, I have read through every relevant post I could find here and believe my question has not been clearly covered. I also understand that "...
5 votes
2 answers
87 views

What is this term in the link budget equation from Space Mission Analysis and Design (SMAD)?

Looking at the 3rd edition of Space Mission Analysis and Design by Wertz and Larson, their equation (13-4) presents the link equation, $\frac{E_b}{N_0} = \frac{PL_\ell G_t L_s L_a G_r}{k T_s R}$, with ...
3 votes
0 answers
55 views

How the number of Sun sensors is chosen for a given spacecraft and mission?

I have to study an ADCS sensors suite and I am struggling to find a criteria to decide how many and in which directions the sun sensors shall be mounted, considering that they are coupled with star ...
2 votes
2 answers
278 views

How can the proposed LUVOIR space telescope slew to different directions while keeping the sunshade in a fixed orientation? What compensates?

In this answer to Why does JWST have such a big Blind Spot? I mention that it moves as a rigid body; in order to change the direction the telescope is pointing the whole spacecraft slews, including ...
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2 votes
0 answers
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General range of maximum RPMs used in reaction wheels in spacecraft?

I was wondering what would be the general range of RPMs used in Reaction Wheels (RW) on a satellite, and I have several closely related questions on this topic: It would definitely depend on the max ...
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1 answer
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Are any space agencies working on an (essentially) 100% reliable sterilization technique for spacecraft bound for subsurface ocean worlds?

One answer to my previous question Is there any demonstrated or even proposed technology that can sterilize a spacecraft with 100% certainty and yet leave it electronically functional? asserts: ...
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13 votes
3 answers
3k views

Has SpaceX chosen to drop the Transpiration cooling of Starship? If so, why?

Earlier, there was news about a proposed concept for Starship to include "transpirational cooling" in its reentry heat shield design. These days there is less news about this and tests so ...
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2 votes
0 answers
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Biggest periscope camera that could fit inside a Starlink satellite; how thick are they?

If all Starlink satellites had phone tier cameras & simple scopes, could images processed by their super-resolution imaging network be competitive? is a cool question and to integrate a reasonable ...
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3 votes
2 answers
268 views

Why haven't we seen more origami in spacecraft?

I remember watching a few videos awhile back talking about origami designs in spacecraft: Origami in Space: BYU-designed solar arrays inspired by origami Engineering with Origami I've only done a ...
12 votes
1 answer
3k views

Why do Teledesic satellites look so weird? What are these structures and where's the satellite bus?

source enlarged and sharpened To my untrained eye I see a weird claw or flower-like antenna array with eight petals in the shape reminiscent of concave dish but not really, that look like they might ...
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4 votes
1 answer
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How did Sputnik 1's antennas couple to its body, electrically and mechanically?

Looking at https://www.britannica.com/technology/satellite-communication/Development-of-satellite-communication I found the image of a model of Sputnik 1 below. It shows details of its four rod ...
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0 votes
2 answers
71 views

First cylindrical Earth satellite? Last?

Sputnik 1 was a shiny metal sphere, as were it's immediate followers. These days Earth satellites are generally rectangular prisms, either one or a few stuck together. Basically big metal chassis ...
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2 votes
0 answers
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what kind of valves are used in payload fairing for venting?

I wanted to know that there have been a handful of literature that mentions vent openings in the rocket payload fairings. However, none specify the kind of valves used in those fairings? does anyone ...
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44 votes
1 answer
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How (the heck) did Lunokhod 2 drive, navigate and survive a ~40 kilometer drive over four months on the Moon using 1970's technology?

Mashable.com's Every rover, ranked by distance traveled on the moon and Mars; The 13 rovers, ranked. calls attention to this amazing feat, and a review of basic statistics and discussions on odometry ...
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9 votes
1 answer
254 views

How do they know that the Dragonfly helicopter won't get quickly coated in tholin muck? Any desliming technology for camera lenses or propellors?

From Air and Space's Dragonfly Is the First Aircraft Built for the Outer Solar System; NASA returns to Saturn’s largest moon with a rover that can fly. which I just found in this heavily-sourced ...
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7 votes
1 answer
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How does the Dragonfly helicopter for Titan compare to Perseverance, Ingenuity and a human in terms of size, mass, weight and daily range?

It wasn't until Are Perseverance's wheels really this big? that I realized just how big Curiosity and Perseverance probably are. Writing What is the pop-up circular disk with spiral pattern in ...
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9 votes
2 answers
790 views

What is the pop-up circular disk with spiral pattern in this NASA animation of the Dragonfly helicopter for Titan? Antenna? Kind, band, target?

At 00:36 in the June 2019 NASA video Dragonfly: NASA's New Mission to Explore Saturn's Moon Titan the animation shows it landing then deploying a circular disk with ...
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20 votes
4 answers
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How well would Max Faget's April 1, 1969 design for the Space Shuttle have actually worked? What would have been the major problems?

This answer to Who are the actual lead designers of manned spacecraft? says (in its entirety): Max Faget was involved in the design of every US manned spacecraft flown to date. Mercury, Gemini, ...
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8 votes
1 answer
513 views

Use of high energy propellants on an engine designed for low energy propellants

This question is about use of high energy propellants on a rocket engine designed for low energy propellants. In any engine, which is currently working on RP1+LOX, if we change the fuel from RP1 to ...
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14 votes
1 answer
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Why did each F-1 engine have dual fuel feedlines?

Each F-1 engine had two fuel feedlines connecting it to the fuel tank as shown in these contemporary photographs and drawings. The corresponding LOX system only had one feedline. The engine had a ...
9 votes
1 answer
186 views

Why are DART's solar panels aligned like this?

I've never noticed this before, but the two solar arrays of NASA and APL's DART spacecraft are at different "levels". In this image, the solar panel on the left extends out from the "...
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1 vote
0 answers
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Articulable/tilt-able solar panels planned for, or already tried on Mars or the Moon to get rid of deadly dust accumulation on solar panels?

From Forbes.com's Mars Opportunity And Spirit Rovers Could Have Lived Practically Forever With One Tiny Change: One option would be to install some mechanism such as wiper blades to remove any ...
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16 votes
1 answer
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Why was the Space Shuttle Orbiter's in-orbit time limited?

I remember reading/watching that the Shuttle had a limited time to stay in orbit. And that's why Soyuzes were the only Assured Crew Return Vehicles (ACRV) for the International Space Station until ...
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4 votes
1 answer
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How did Gagarin's flight affect improvements to the Vostok capsule?

Every spaceflight is an opportunity to learn what does not work well and to improve the vehicle for the next flight. Did Yuri Gagarin's first human spaceflight yield any changes to the capsules or ...
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Pressurant gas line design considerations

I am trying to understand the constraints on pressurant gas line sizes and lengths. For a static volume, the lines can be small in diameter because there is no significant flow velocity and therefore ...
1 vote
1 answer
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Could an orbital launcher look like a scaled up Nike Hercules?

We now have flyable, recoverable suborbital boosters, which would be the first stage. The second stage of the Saturn V rocket was able to hurl the 100 ton Skylab into an orbit over 250 miles high. ...
3 votes
0 answers
99 views

Why are strap-on boosters more often attached radially in Eastern-European/Asian rockets, and bilaterally in Western-European/American rockets?

While comparing launch vehicles with strap on boosters, it appears to me that the majority of Eastern-European/Asian vehicles arrange the boosters radially, but the Western-European/American vehicles ...
9 votes
1 answer
303 views

What do large, modern communications satellites look like inside (roughly at least)?

Modern communications satellite in GEO are big, majestic beasts. They are quite large and voluminous. They can sport quite an array of antennas and handle huge bandwidths and multiple communications ...
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4 votes
0 answers
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How efficient was Telstar's solar cell configuration, compared to a flat panel?

Telstar was a series of communication satellites first launched in 1962. The body of the satellite is roughly spherical, with much of the outer surface covered in solar cells. This gives the ...
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7 votes
2 answers
380 views

Which explode in spaceflight more often, nuts or bolts?

The history of spaceflight is littered with exists because of exploded nuts and bolts (and upon further reflection, a whole lot of other items!) "Exploding bolts" is really a generic term. ...
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