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Questions tagged [engineering]

Questions regarding the design or process of design of a spacecraft.

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47 votes
8 answers
13k views

What would be the (most difficult) challenge to make a 10,000 year satellite?

Update: Bezos' recent Tweeted update on the 10,000 year clock. Also see The Verge's Construction begins on Jeff Bezos’ $42 million 10,000-year clock The discussions associated with the question Can ...
uhoh's user avatar
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34 votes
8 answers
13k views

What led NASA et al. to decide the ISS should be a zero-g station when the massive negative health and quality of life impacts of zero-g were known?

As the month of November 2020 has marked 2 decades of the ISS being operational as well as the first operational flight of a next-generation spacecraft to it, I felt it fit to ask this question today. ...
Grant Hartlage's user avatar
34 votes
1 answer
9k views

How do manned spacecraft achieve an airtight connection while docking?

By another question I was reminded how hard it is to build airtight equipment such as vacuum chambers from multiple pieces. Docking or berthing space ships / space station modules is a rather similar ...
s-m-e's user avatar
  • 6,461
33 votes
1 answer
4k views

Why do the Shuttle's external tanks appear to be rusted?

Wikipedia article states as STS-1 at liftoff. The External Tank was painted white for the first two Space Shuttle launches. From STS-3 on, it was left unpainted. I wonder why the ...
Hash's user avatar
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32 votes
8 answers
8k views

Apollo: what was the big deal?

I am curious what aspects of the Apollo program were impressive/advanced from an engineering perspective, in the 1960s and 1970s. That is, what would have made an educated engineer say, “Wow, they ...
adam.baker's user avatar
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28 votes
1 answer
4k views

How realistic would the Sea Dragon engine be to produce given today's technology?

Just learned of the Sea Dragon proposal from back in 1962. From the Wikipedia entry The first stage was to be powered by a single enormous 80,000,000 pounds-force (360 MN) thrust engine burning RP-...
Ezra Bailey's user avatar
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27 votes
4 answers
10k views

Why is SpaceX building the Big Falcon Ship before the Big Falcon Rocket?

I believe that SpaceX is planning on building the BFS (Big Falcon Spacecraft) before the BFR (Big Falcon Rocket), which serves as the first stage for the second-stage BFS. Does anyone know why they ...
Slarty's user avatar
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25 votes
3 answers
5k views

How realistic is the 1 kg/km² solar sail in "Death's End"?

(This question has been migrated from the SciFi StackExchange.) From Cixin Liu's 2010 sci-fi novel Death's End (pages 68–69): "A radiation sail can be made very thin and light. Based on the ...
Quuxplusone's user avatar
25 votes
2 answers
5k views

Why do pressure fed engines have combustion instabilities?

Reading about the Sea Dragon idea, I came upon this argument against it, which sounds compelling, but relies on more detailed knowledge than I have: Those are to be pressure-fed to avoid "...
AlanSE's user avatar
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22 votes
2 answers
11k views

What is the ideal shape for a rocket?

Obviously there are many factors that go into the design of a rocket. However, to me, many rockets seem very tall and skinny. What I mean is that an ideal rocket would have as little mass used for ...
DarcyThomas's user avatar
21 votes
3 answers
5k views

Why isn't there research to build a standard lunar, or Martian mobility platform?

While many terrestrial mobility platforms have been very successful, why are we spending millions to every rover device making it unique? Sure enough, different worlds offer different conditions, but ...
J. Doe's user avatar
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21 votes
3 answers
3k views

How does the Saturn V Dynamic Test Stand work?

This photo instantly provokes a ton of questions in me: It shows the Dynamic Test Stand at Marshall SFC with the Enterprise, which was a Space Shuttle test vehicle, suspended for vibration testing. ...
kim holder's user avatar
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21 votes
1 answer
8k views

How did they solve Saturn V pogo oscillation problems?

From what I understand, pogo oscillation was already a known problem for Saturn V rocket's first stage (and likely other stages, not sure) long before, say, Apollo 11, especially on its central out of ...
TildalWave's user avatar
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20 votes
3 answers
5k views

How are fuel tanks filled with cryogenic hydrogen?

Cryogenic hydrogen can react with the atmospheric Oxygen to produce an explosion: as well as being cold enough to liquefy (and possibly solidify) atmospheric oxygen, which can be an explosion ...
Hash's user avatar
  • 18k
19 votes
3 answers
5k views

Why are Curiosity's wheels aluminum rather than titanium?

I was just reading this article on how Curiosity's aluminum wheels are getting pretty dinged up. Usually titanium alloy is considered an upgrade from aluminum alloys in most applications, from ...
joseph_morris's user avatar
17 votes
1 answer
3k views

Why design new rocket engines instead of using the existing types?

Already in the 1960s rocket engines seem to have achieved near maximum chemical efficiency. What are the reasons for new designs being in demand? How much better could a new engine design be than the ...
LocalFluff's user avatar
17 votes
3 answers
2k views

Why do KSC crawler-transporters use caterpillar treads instead of rail tracks?

The two Kennedy Space Center crawler-transporters, used to transport Saturn V, Shuttle and SLS rockets to the launchpad, move on caterpillar treads: Here's a SpaceFlight Insider video clip about ...
LocalFluff's user avatar
16 votes
2 answers
4k views

How hot do rocket engine nozzles get?

What temperatures are encountered by the nozzles of rocket engines like those in SpaceX's Merlin series? Radiative or regenerative cooling, atmosphere or vacuum. There's plenty of info about exhaust ...
Camille Goudeseune's user avatar
15 votes
4 answers
2k views

What is the intent of attaching legs to the rocket?

SpaceX Adds Landing Legs to Falcon 9 Rocket for Next Launch Still thinking why they added legs to the rocket's first stage? What are the advantages of attaching the legs to the rocket? Does that ...
Hash's user avatar
  • 18k
15 votes
4 answers
6k views

How feasible is it to harvest isotopes of Helium or Hydrogen from the gas giants?

The gas giants in our solar system have abundant quantities of Helium and Hydrogen. Is it possible to harvest these resources there? Does NASA have any plans to build some permanent base in space for ...
Shuhao Cao's user avatar
15 votes
1 answer
684 views

How much energy is lost by damping yaw from a SpinLaunch?

SpinLaunch hopes to launch a 200 kg satellite from a ground-based centrifuge, at 5000 mph, and more troublingly, at 450 rpm aka 7 tumbles per second. (The 3000 rpm figure mentioned in its tech sheets ...
Camille Goudeseune's user avatar
13 votes
5 answers
3k views

Which US Air Force career should I be in for the best chances at becoming some sort of electrical engineer at SpaceX? [closed]

I flunked in high school and early college because I wasn't in the right mindset. No drive or motivation to do my best. I now want to pursue SpaceX's vision because it's similar to my vision, and I ...
SHOCK's user avatar
  • 131
13 votes
2 answers
5k views

Transitioning into space software engineering

I have been a Web Developer in London since I graduated in 2012. My skills reside mainly in the Microsoft stack (MSSQL, .NET, C#, MVC and all the front-end stuff). I have always been very interested ...
Andy Furniss's user avatar
13 votes
1 answer
6k views

How does a space probe differ from a satellite in terms of materials used and size?

Both of those space vehicles are meant to carry out different tasks. How are materials selected for both of them such that it benefits their task? And is size a debatable factor while building these ...
Paran's user avatar
  • 965
13 votes
4 answers
8k views

How big would a manned ascent stage for Mars need to be?

For a manned mission to Mars that isn't a one-way trip, we'll need an ascent stage that can reach orbit from Mars' surface. How big would this need to be to transport e.g. 3 astronauts to orbit? We've ...
Hobbes's user avatar
  • 128k
13 votes
1 answer
1k views

Purpose of hemisphere under shuttle nose cone (Enterprise)

I noticed a small hemisphere protruding from the dorsal side of the Enterprise space shuttle's nose cone, forward of the front landing gear. I have no clue what its purpose is but am far from an ...
user3769181's user avatar
13 votes
1 answer
11k views

What material properties would be necessary to shield a lander from the environment of the Venusian surface?

On March 1, 1982, the Venera 13 lander survived for 127 minutes in an environment with a temperature of 457 °C (855 °F) and a pressure of 89 Earth atmospheres (9.0 MPa). This says nothing of the ...
Anthony Neace's user avatar
13 votes
1 answer
1k views

Why does the YF-75D nozzle have such a strong spiral pattern?

Why does the YF-75D nozzle material have such a strong spiral pattern? Is it a result/biproduct of a manufacturing process only, or does it have some specific function? edit: The last, cropped ...
uhoh's user avatar
  • 149k
12 votes
2 answers
421 views

What mitigation procedures are in place in space systems to prevent whisker growth?

It has been found (from missions like the Long Duration Exposure Facility, LDEF) that some metals, especially tin and cadmium in solders, used in space-electronics assemblies, form crystal whiskers ...
My Other Head's user avatar
12 votes
1 answer
2k views

Why was the Hubble Space Telescope purged with nitrogen gas?

Wikipedia states that The telescope had to be kept in a clean room, powered up and purged with nitrogen, until a launch could be rescheduled. Spacecraft are always kept in a clean room ...
Hash's user avatar
  • 18k
12 votes
3 answers
1k views

Strategies for combating ESD and ground plane potential shifts on spacecraft charging?

What are some common design guidelines/practices to combat the electrical effects of spacecraft charging(e.g. ESD, ground plane shift). Is it to focus on more resilient parts, and reduce resistance/...
user5826's user avatar
  • 121
11 votes
4 answers
42k views

Becoming an astronaut with engineering background

Which engineering branch will be most suitable for becoming an astronaut, and what other options do I have if I want to become an astronaut with an engineering background?
D.S. Maura's user avatar
11 votes
2 answers
511 views

What happens next if the root cause of one rocket failure won't be identified?

Supposing that in a rocket failure engineers don't find what the root cause was, what will happen next? In general if the root cause will never be fully understood is there a law, rule, or standard ...
J. Young's user avatar
  • 255
11 votes
1 answer
1k views

Function of the RL10 Oxygen Turbopump's Splined Shaft End

The oxygen turbopump in the RL10 upper stage engine has been openly discussed by NASA for some decades now, in publications like SP-8107. On page 8 of this document is a drawing of this turbopump. The ...
Rikki-Tikki-Tavi's user avatar
10 votes
4 answers
697 views

Who are the actual lead designers of manned spacecraft?

By "lead designer" I mean a person who oversaw the preliminary design phase for a manned spacecraft, being intimately involved in and ultimately responsible for crucial design choices and compromises. ...
Deer Hunter's user avatar
  • 11.4k
10 votes
1 answer
527 views

What improvements does SpaceX Falcon 9 Block 5 have over prior version?

Does SpaceX disclose what improvements their Falcon 9 Block 5 will have over the Block 4 model? If so, what improved features will it have? I have heard general comments about it in the news, but I ...
Dan Sorensen's user avatar
  • 3,571
10 votes
3 answers
3k views

Troubleshooting a DIY Ion Thruster

Been following a Make-Magazine article on how to make your own ion thruster: https://makezine.com/projects/ionic-thruster/ Went through the tutorial step by step, not seeming to get any thrust out of ...
Colin Warn's user avatar
10 votes
2 answers
452 views

Which are the benefits and challenges for a new SLS rocket version with four SRB? [closed]

Which are the benefits and the challenges for a new Space Launch System (SLS) version with four Solid Rocket Boosters (SRB)? Benefits i mean what would gain in payload capabilities, how much more ...
J. Young's user avatar
  • 255
10 votes
1 answer
832 views

Has any work been done on alternatives to rolling element bearings in rocket turbopumps?

Specifically: Using some high pressure gas (before or after combustion) as a fluid bearing. A superconducting maglev bearing, possibly using fuel as coolant. Any related work is also welcome.
Mercury's user avatar
  • 103
10 votes
2 answers
287 views

What is it about parachutes that makes people always want to "re-invent the wheel"?

For technology that involves complex engineering issues, standardization and specialization is extremely helpful. If I want to design a complex ASIC IC I don't design it from scratch, I just drag-and-...
uhoh's user avatar
  • 149k
9 votes
1 answer
739 views

Sea level static test of an upper stage possible?

As we know that for the upper stages of the rocket, we need high propulsion efficiency thereby high specific impulse. For that we employ a nozzle with higher expansion ratios. Now, if we conduct the ...
cosmic_tintin's user avatar
9 votes
2 answers
2k views

How are spacecraft engineered to prevent overheating?

Been reading about early space exploration again, especially Sputnik 2 (1957) and Venera 1 (1961). Both of these suffered from overheating. It strikes me that a metal object will easily "absorb" the ...
DrZ214's user avatar
  • 4,596
9 votes
1 answer
3k views

Why is a purging process necessary for static firing test of liquid rocket engines?

In Chapter 7 of Modern Engineering for Design of Liquid propellant Rocket Engines by Huzel and Huang, mentions the following engine cut off procedure. The cutoff sequence usually consists of ...
karthikeyan's user avatar
  • 4,479
9 votes
4 answers
323 views

What engineering processes (satellite/space vehicle related) require an atmosphere

So we all know that there are lots of engineering processes that are made 100 times better by negligible gravity, and that certain engineering process need to be performed in a vacuum (electron beam ...
ThePlanMan's user avatar
  • 4,431
9 votes
1 answer
411 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 ...
uhoh's user avatar
  • 149k
9 votes
1 answer
748 views

Why were individual shuttle tiles changed from white to black or black to white?

The Paper Space Scale Models website has a PDF which details changes to the STS Orbiter Markings on a per-mission basis. Most of the changes are in the tiles. It can be seen that often a single black ...
dotancohen's user avatar
  • 6,784
9 votes
1 answer
2k views

What are/were the rails leading into the flame trench of pad 39A used for?

In this Google Street View you can see what appear to be rails leading down into the flame trench under launch pad 39A. What was/is the purpose of those rails?
ForgeMonkey's user avatar
  • 7,119
9 votes
1 answer
290 views

How far did the MUSTARD project get?

http://www.astronautix.com/m/mustard.html As described above, MUSTARD was a BAC project to develop a fully reusable VTO/HL shuttle to transport crew and payload to earth orbit. There were many ...
AnarchoEngineer's user avatar
9 votes
1 answer
193 views

Do modern CFD codes reduce the number of test firings in an engine program?

Given the complexity of liquid propellant rocket engine development, I wonder if (and how much) modern Computational Fluid Dynamics (CFD) codes help to reduce overall development costs. Do they ...
Deer Hunter's user avatar
  • 11.4k
9 votes
1 answer
242 views

How heavy were Perseverance's balance masses?

Perseverance ejected two 70 kg "cruise balance masses" just before it became an airplane, to move its center of mass off axis and increase its angle of attack from 0° to about 16° to make it ...
Camille Goudeseune's user avatar