83

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 speculate about how that shorthand evolved. Example: Assume the thrust of an engine according to its design and specification -- its nominal thrust -- is 45 kN, ...


80

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 contains a vast number of second order acronyms, but the example above is the only third order acronym I could find through initial analysis.


70

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 of semantics. The authors of this paper discuss "areostationary" for Mars orbits as opposed to "geostationary" for Earth, and Wikipedia uses the same convention,...


60

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. On this geographic feature Cape Canaveral is built Cape Canaveral Air Force Station. Today's Kennedy Space Center (KSC) is built on Merritt Island. Even ...


55

For a powered descent to the surface of a massive body like the Moon, it turns out to be most fuel efficient to do all your deceleration at the very end of the trajectory, right before impact. (This is because if you decelerate sooner than that, you will be in flight longer; the longer you're up, the more fuel you need to spend counteracting gravity ...


54

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 of the most versatile of the Greek gods. Dr. Silverstein recalls he chose the name after perusing a book of mythology at home one evening, early in 1960. He ...


51

So far as I can tell, it was first a saying used by military personnel as the phrase "Rapid Unintentional Disassembly", for a phrase when a gun broke apart if you misused it. This was used by a book for Navy Personel in 1970, so I suspect it was in use for a while before then. This seems to have evolved from that phrase somewhat over the years. The earliest ...


48

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.


47

It has many names, depends on who you ask. In English, one name for our moon is simply the Moon. Notice the article the and the capitalization making it a proper noun. This is similar in convention as the Galaxy for our own galaxy that is otherwise also known as the Milky Way. But the word galaxy actually already implies something related to milk in Greek ...


47

I gave an example of one a while back in this answer: Alternate version by Magic Octopus Urn Alternate version by Eric Duminil


46

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 mission that the rock/ice in the core account for 5–25 of these Earth masses. So the rest of about 300 Earth masses is gas. Thus Jupiter is a gas giant. It is ...


45

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, specific energy means the total amount of energy you can get from one unit mass of battery. As described in the Wikipedia article, *specific impulse" is the ...


45

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. Some companies specialize in mission design consulting, like Space Exploration Engineering, Advanced Space LLC, or the X Team from JPL (although the latter ...


35

"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 the word "engine" is to liquid rockets... Rocket Propulsion Elements, Sutton, 4th edition, p. 354 Anecdotally, at least on shuttle you could get away ...


34

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 rules are quite different for each. See this map from Wikipedia to show the different locations. Note that Kennedy (NASA) owns launch pad 39a and b, while the rest ...


30

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 propellant tank, it's important that the ullage volume be kept away from the inlet that leads to the engines, because you want the liquid going into the engines. ...


29

The basic difference between docking and berthing methods is as described by @OrganicMarble and the linked article, that berthing involves the robot arm and docking does not. The reasons why one is used rather than the other was discussed by the NASA PRO in a recent webcast. Obviously, if the vehicle is not capable of docking it must be berthed; however it ...


28

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. For Mars, the terms areostationary and areosynchronous are (sometimes) used. This follows the convention of how apsides are named, so it is likely that the ...


27

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, would be the green line in your image. Anything closer than the horizon will be visible to the spacecraft. area Note also that even though the area appears to have ...


26

We are "in space", in fact everything that exists and has a physical presence is. But what we usually mean by it is to describe "outer space" conditions of near (or hard) vacuum, where atmospheric pressure is already low enough to affect matter differently than under true atmospheric conditions, for example at atmospheric pressure below triple point of water....


26

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 engine is a device that burns or otherwise consumes fuel, changing its chemical composition, and a motor is a device driven by electricity, air, or hydraulic ...


24

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 appreciate updates).


23

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 they're held on. One of the straps, near the base of the booster, is shown highlighted in blue here: This RussianSpaceWeb page has a rendering of the boosters ...


23

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, like the Atlas V, the number of boosters can be customized per-mission. Also, in some cases the booster design is shared between launchers like the Shuttle and ...


23

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 hardly ever used in titles of scientific publications. From google scholar, there seems to be a few publications about LIBS that use the term. In conclusion, it ...


21

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 satellites and communications satellites. SE's answer about the horizon applies if the satellite is viewing the entire visible portion of the globe at once. As ...


20

The “Sailboat Island” gets its name from a Poincaré Surface-of-Section (SOS) plot of potentially stable S-type family of orbits in the Pluto-Charon system. From NASA Ames' blog post titled Playing Marbles at Pluto. Looking at the Dynamic Dust Environment. Generators, Sweepers, and Sweet-Spots by Kimberly Ennico: Othon Winter (UNESP Brazil) spoke about “On ...


20

The terms docking and berthing have a nautical origin. Smaller ships come into port under their own authority and dock. Large ships instead are berthed. They come to a stop outside of the port, relinquish control to the port authority, and are towed into port by tug boats. Docking with the International Space Station is essentially a controlled collision ...


19

Edit: Thinking about this some more, the answer is a result of physics: gases exert pressure (due to molecules bumping into each other). This is what causes a gas to expand to occupy all available volume. The only force at work is a repellent one, so the answer must be "blown out". In everyday language, there are some exceptions. We say a vacuum cleaner ...


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