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85 votes
Accepted

Why do space operations use "nominal" to mean "working correctly"?

As explained in the answer that Organic Marble dug up, aerospatial "nominal" is really a shorthand for something like within the allowed tolerances around the nominal (i.e. specified) value. We can ...
Russell Borogove's user avatar
80 votes

Are there any “Third Order” acronyms used in space exploration?

Yes. NUTI => NASCOM User Traffic Interface NASCOM => NASA Communications NASA => National Aeronautics and Space Administration Found by parsing this list of over 14,000 NASA acronyms It also ...
SE - stop firing the good guys's user avatar
71 votes
Accepted

Name for geostationary orbit around another planet

I'll go with Emily Lakdawalla who in her blog post about stationkeeping in Mars orbit wrote (emphasis mine), What is a geostationary orbit like at Mars? I have to pause here for a brief discussion ...
David Hammen's user avatar
60 votes
Accepted

What is the difference between Cape Canaveral and Kennedy Space Center?

Supplementary answer: Some of the confusion arises because there is also a geographic feature named Cape Canaveral. It's pretty much the green area shown in the other answer, east of the Banana River....
Organic Marble's user avatar
55 votes
Accepted

Was "Apollo" an acronym for "America’s Program for Orbiting Lunar and Landing Operations"?

From a pre-launch press release for Apollo 11: Among the many missions conceived at that time was a manned journey to the Moon and back. Dr. Silverstein himself named it "Apollo" after one ...
PearsonArtPhoto's user avatar
  • 121k
50 votes

What is "mission design"? What do mission designers do (if such a designation exists)?

Yes, there are people whose sole job is "mission design." They design the trajectory that a spacecraft should follow to fulfill its mission and all of the maneuvers needed for that to happen....
ChrisR's user avatar
  • 6,180
49 votes

What is an "octet" in the context of NASA's LunaNET Interoperability Standard? ("internet on the Moon")

An octet is an 8-bit byte. Historically, "byte" wasn't always 8 bits (and still isn't, with some architectures having different byte sizes today); "octet" is unambiguous and widely ...
Russell Borogove's user avatar
48 votes
Accepted

Why is Jupiter called a "Gas Giant"?

Jupiter being a gas giant is not about its appearance, as another answer stated. It's only about the mass distribution of a planet. Jupiter's mass is 320 Earth masses, while we know from the Juno ...
AtmosphericPrisonEscape's user avatar
48 votes

Do scientist who study martian geology typically use the term areology?

Good question. I work on the Curiosity team, and I hear "geology" all the time, but never "areology." Too bad, really, since it's a great word, and I love the R/G/B Mars series.
foobarbecue's user avatar
  • 1,405
47 votes

Are there any “Third Order” acronyms used in space exploration?

I gave an example of one a while back in this answer: Alternate version by Magic Octopus Urn Alternate version by Eric Duminil
Organic Marble's user avatar
46 votes
Accepted

What is the story behind specific impulse being expressed in seconds?

It's even simpler than a German-American disagreement. It's use of ambiguous units. The term "specific X" means the amount of X you can get from a unit mass of something. For instance, in batteries, ...
Tom Spilker's user avatar
  • 18.3k
37 votes

Who coined the phrase 'Rapid Unscheduled Disassembly'?

Here's a reference from 1967 in "The MAC Flyer", Volume 14, Issue 5. This appears to be a periodical of the US Military Airlift Command. I have not been able to locate full text (but would certainly ...
Resuna's user avatar
  • 471
36 votes
Accepted

What is an "octet" in the context of NASA's LunaNET Interoperability Standard? ("internet on the Moon")

Is "octet" just a fancy word for "byte" No, they mean very different things. A "byte" is the smallest unit of addressable memory of a specific CPU architecture. That ...
Jörg W Mittag's user avatar
35 votes

Can "engine" and "motor" be used interchangeably in spaceflight? Are there any cases where they can't be?

"Motor" by convention refers to a solid rocket, "engine" by convention to a liquid rocket. There can be exceptions. ...the word "motor" is as common to solid rockets as ...
Organic Marble's user avatar
34 votes
Accepted

What is and what isn't ullage in rocket science?

But I still don't completely understand what is or isn't ullage in rocket science context. Ullage technically is the space in a tank of liquid which is gas-filled instead of liquid-filled. For a ...
Russell Borogove's user avatar
33 votes

What is the difference between Cape Canaveral and Kennedy Space Center?

Cape Canaveral is composed of two items, the Kennedy Space Center, run by NASA, and the Cape Canaveral Air Force Base, run by the Air Force. Because they are two very different organizations, the ...
PearsonArtPhoto's user avatar
  • 121k
32 votes
Accepted

What is "anti-geysering" and why would you turn it off 70 seconds before launch?

Partial answer to What is "anti-geysering"... tl;dr Anti-geysering systems are intended to stop geysering, which is a phenomenon that can occur in long vertical pipes of cryogenic fluid ...
Organic Marble's user avatar
29 votes
Accepted

What is the name of the area on Earth which can be observed from a satellite?

What is the name of this line or this area? line A term for the line that's perfectly usable for this purpose is "horizon". The horizon, the line line separating the land from the sky, ...
SE - stop firing the good guys's user avatar
28 votes

Name for geostationary orbit around another planet

Geostationary orbits are synchronous orbits, which are also circular and equatorial. You could describe orbits around other planets in the same way, as circular, equatorial & synchronous orbits. ...
Polygnome's user avatar
  • 6,956
26 votes

Can "engine" and "motor" be used interchangeably in spaceflight? Are there any cases where they can't be?

According to Wikipedia, they are effectively interchangable: Motor and engine are interchangeable in standard English. In some engineering jargons, the two words have different meanings, in which ...
Russell Borogove's user avatar
24 votes
Accepted

Are any "strap-on" boosters held in place by actual straps?

The Soyuz line all the way back to the R-7 has straps or cables connecting the boosters to the core. The straps, plus a "socket" on the core catching the front tip of the booster, are apparently how ...
Russell Borogove's user avatar
23 votes

Why "strap-on" boosters, and how do other people say it?

These boosters are called “strap-on” because there is little structure besides the separation mechanism holding them on, and the rocket is still a viable launch vehicle without them. In a few designs, ...
CourageousPotato's user avatar
23 votes
Accepted

Do scientist who study martian geology typically use the term areology?

A search on arXiv for "areology" produces no results. A search on ADS produces two results (one of which has the subtitle "The Geological Environment of Mars"). So the term is ...
usernumber's user avatar
  • 5,068
23 votes

What is the name of the area on Earth which can be observed from a satellite?

What is the name of this line or this area? Typically, the part of the earth's surface that a satellite can view at any moment is known as its footprint, a term frequently used for remote sensing ...
Duncan C's user avatar
  • 347
23 votes

Term for deformation due to gravity

The generic term is tidal deformation. At a distance of ~385000 km, the Moon subtly distorts the shape of the Earth. Those distortions are readily visible in the Earth's oceanic tides, and not quite ...
David Hammen's user avatar
20 votes
Accepted

Nuances of the terms (mean / osculating / Keplerian / orbital) elements

Your assumption is a good starting place and its good to be cautious about it. Many of us are guilty of abbreviation or outright misuse of the terms for convenience. Here's my rough guide, not meant ...
Puffin's user avatar
  • 9,684
20 votes

What is the difference between a space plane and a space shuttle?

A plane, or airplane, aeroplane, is: An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. All ...
user3528438's user avatar
  • 1,641
19 votes

Is the air "sucked out" or "blown out" into space when the hatch opens?

Both are correct, it just depends on who/what is doing the verb (sucking/blowing). In english we would call this the subject of the sentence. Consider the following scenario. You have two large tanks, ...
Jeffrey Phillips Freeman's user avatar
19 votes
Accepted

What does "in the bucket" mean?

The space shuttle throttled down its main engines from the normal setting of approximately 104% to around 67% as it was passing through the region of max dynamic pressure ("max q"), to make sure that ...
Organic Marble's user avatar

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