82

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, ...


77

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.


68

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,...


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 ...


39

I gave an example of one a while back in this answer:


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 ...


26

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. ...


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 ...


16

While not exactly space exploration there is at least one fourth order acronym for NASA earth observation systems (mostly earth sensing satellites). EPR - EED2 Program Roadmap EED - EOSDIS Evolution and Development EOSDIS - Earth Observation System(EOS) Data and Information System EOS - Earth Observing System NASA - EOSDIS Acronym List


12

In shuttle parlance the "flight deck" was the upper floor of the three-story crew module, the middeck was, erm, the middle floor, and the ECLSS (or Lower Equipment) bay was the lower floor. The flight deck included both the forward facing airplane mode controls and the aft facing robot arm and rendezvous controls. If the term cockpit was used - and in my ...


11

Perhaps "Clarke orbit"? The definitions always talk about Earth but at least it's not in the term. https://en.m.wiktionary.org/wiki/Clarke_orbit


10

For French and Ariane 5 Several names are used. EAP is the most common one « Étage d'Acceleration à Poudre » which could be roughly translated to « acceleration powder stage» An other more generic term used is « propulseur d’appoint » which translate to « complementary propulsion device » For Japanese and H-IIA Take this with a grain of salt my ...


9

Boosters were in use by 21 August 1957, the first successful suborbital launch of the R-7. Definition of 'booster': A booster rocket (or engine) is either the first stage of a multistage launch vehicle, or else a shorter-burning rocket used in parallel with longer-burning sustainer rockets to augment the space vehicle's takeoff thrust and payload ...


9

The problem with the word "rocket" is that it is a colloquialism, subject to use by non-experts and not an exactly-defined term. The term "Rocket" is used for any vehicle that's propelled by one or more rocket engines. The Cambridge Dictionary is wrong. Rockets are typically cylindrical, but not universally. Famous counterexamples: N-1, V-2. Merriam-...


8

Partial answer - don't know how to answer the "how often" part. It's a historical artifact - they had years of Titan documents, procedures, display and controls, etc referring to the "first stage" and the "second stage." They're not going to go back and change all that because somebody had the bright idea of airstarting it. Nope, we'll just call the ...


7

In his memoir "Liftoff", Michael Collins (Command Module pilot on Apollo 11) called it the sky. It is a quiet interval and we get a chance to examine our surroundings, this strange region called cislunar space. Is it daylight? Yes, the sun is definitely shining on us. Is it dark? Yes, if we shielded our eyes from the sun, the sky is flat black ...


7

The terminology is even less rigorous than that! Skirt, nozzle, and bell can informally refer to the same thing. Bell seems to be shorthand for bell nozzle, a common shape for a nozzle. One chapter in a book (preview) confusingly does not distinguish between skirt, skirts, and skirt structures. "Skirts" suggests Victorian hoop skirts, which indeed look ...


7

If "tangential velocity" is not tangental to the orbit, what else can it be tangential to? I studied orbital mechanics in Howard Curtis' Orbital Mechanics for Engineering Students, and while I don't claim that it holds absolute truth, it uses the same definition as the diagram you posted (but less clutter): (Figure 2.8 from H. Curtis, Orbital Mechanics for ...


6

No, it's not redundant. The abbreviation GEO expands to Geosynchronous Equatorial Orbit. A geosynchronous orbit that coincided with the Earth's equatorial plane would then also be geostationary.


6

When I started at McDonnell Douglas in 1977, the term was RUDE, as in a "RUDE rocket". Rapid, Unplanned Disassembly Event. It was listed in a book full of industry acronyms I was required to read during my first two weeks. Bit was another term defined therein: Binary digIT.


6

It is a “Fast Mission” opportunity. These are missions that address an opportunity in the near future that would possibly be missed with the normal mission development timeline. Historically, ESA missions are classified as Large (L), Medium (M) or Small (S). The distinction is not on size of the payload, but on the technology development required for the ...


6

What the heck are "space-fixed coordinates"? To what in space can a coordinate system be fixed? That's two questions. The answer to the first is that those are Earth-centered inertial or Moon-centered inertial coordinates as indicated by the "Ref. body" column. Look at the velocities. 25600 ft/sec is orbital velocity for a vehicle in low Earth orbit while ...


5

Terms like "correct" and "right" might imply the condition might be checked further beside the value being inside the acceptable parameters, so it’s good to stay away from that. Terms like "normal" might imply not the specific condition or even worse a comparison with some historic averages. For that reason having a less loaded term (implying you are only ...


5

Long time, no answer, so I'll take a stab at it...please be aware that all of my "evidence," while purely anecdotal, is first hand. I never heard the subject term, "lead head" used in this context (I was in The Office from 1996-2004, inclusive). It was frequently said, however, that, "You pay going up, or you pay coming back, nobody flies in Space for free."...


5

During his tenures as Chief of the Astronaut Office and Director of Flight Crew Operations, Deke Slayton had the greatest influence over the titles of astronauts. NASA's predecessor agency -- the National Advisory Committee for Aeronautics (NACA) -- was more involved in aircraft than spacecraft. Their research resulted in the Bell X-1 supersonic aircraft ...


5

The technical term for them is "handrail". Image source: http://www.hunchdesign.com/uploads/2/2/0/9/22093000/restraint_and_mobility_aids.pdf IVA (IntraVehicular Activity) Handrail if you want to be formal. Table source: https://snebulos.mit.edu/projects/reference/International-Space-Station/SSP50008RC.pdf


4

According to the Wikipedia article on the Titan IIIC the first flight of that vehicle was on 1965 June 18. Prior to that, on 1964 August 19 a successful flight of a rocket variously known as the "Thrust Augmented Delta" (TAD) or "Delta D" or "Thor-Delta D" ushered in operational use of strap-ons for US launch systems. The TAD flew again successfully on 1965 ...


4

The other answerer is on the right track. I believe the description of a "high energy geostationary orbit" is a mistake on the part of the author: it should be called a "high energy geostationary transfer orbit" (hereafter GTO). First, let me detail how a traditional GTO is used from an inclined launch site. The launcher will throw the satellite into a ...


4

The transfer orbit for Arabsat 6a went to an apogee of 90,000km. At that height it's travelling very slowly, so adding delta-V needs less energy. The sat needs both to remove the launch inclination (i.e. 28.5 -> 0) and at the same time raise the perigee to geostationary altitude. Then, when the sat reaches perigee the engine is fired again to circularise the ...


4

The term you are looking for is most likely Lagrangian point. Often synonymous, but sometimes used less strictly is Libration point. It's important to be careful about exactly what we mean when we say "cancels out", "equilibrium" or "static". When we have more than one body, they can't all be static. If they didn't move relatively to each other, their ...


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