Terminology, Definitions and Acronyms


Graphics from NASA website

[[  Most recent Update: 29 October 2015, Inserted a missing graphic and corrected a couple of grammatical errors.  ]]

As promised in my previous post, here is a list of  Terminology, Definitions, and Acronyms I have accumulated during my research into space travel in general and NASA jargon in particular.

I hope you will find the list to be useful and interesting.  The list will grow as I do more research into this fascinating subject.

Asteroid Redirect Mission (ARM): This mission (or missions) will place an asteroid into cislunar space as well as return samples to the ISS and/or Earth for further study.

Asteroid Redirect Robotic Vehicle (ARRV): The Asteroid Redirect Mission (ARM), also known as the Asteroid Retrieval and Utilization (ARU) mission and the Asteroid Initiative, is a potential future space mission proposed by NASA. Still in the early stages of planning and development, the spacecraft would rendezvous with a large near-Earth asteroid and use robotic arms with anchoring grippers to retrieve a 6-meter boulder from the asteroid.

Cislunar: The spherical space surrounding the earth with a radius of the distance from the center of the earth to the center of the moon.

European Space Agency (ESA): The European version of NASA.

Exploration Upper Stage (EUS): A rocket stage that sits atop the Core (main) stage of the SLS rocket, Block 1B and Block 2 assemblies. There are three versions of the SLS rocket: Block 1, Block 1B, and Block 2 (see SLS, below, for details).

A drawing of the various parts of Core section of the Block 1 SLS Rocket follows:

Block 1 Core Components

The Core stage of the SLS rocket is 212 feet tall ( 64.6 meters) and 27.6 feet diameter (8.4 meters) includes (bottom to top):

[] The four RS-25 main engines.
[] Liquid Hydrogen fuel tank.
[] Intertank Connector.
[] Liquid Oxygen fuel tank
[] Forward Skirt

To illustrate and emphasize the scale of this Core section, a photo of a technician inspecting welds on the top of the Liquid Hydrogen fuel tank is shown below:
Hydrogen TankDome
Commercial Crew Transportation Capability (CCtCap): A program in progress to use COTS to carry supplies to the ISS with vehicles supplied by Boeing, Space X, etc.

Commercial Orbital Transportation Services (COTS): A NASA sponsored program to encourage companies to develop systems to provide supply services to cislunar space. Companies such as Boeing and Orbital ATK have already begun to deliver cargo to the ISS.

Commercial Resupply Services (CRS): Part of COTS

Entry, Descent, and Landing (EDL): Stages of taking things from orbit and placing them on the surface of a planet, moon, asteroid, or comet.

Indian Space Research Organization (ISRO): The Indian version of NASA.

In Situ Resource Utilization (ISRU):  A type of device that will produce essential resources, such as Oxygen on the ISS and eventually on Mars. Also, see MOXIE, below.

International Space Station (ISS): One of America’s National Laboratories where LEO research and training is done. As of October 2015 astronauts from 17 countries have lived and worked on the ISS for various periods of times during the past 15 years or so. Currently (October 2015) two astronauts (one Russian and one American) are about half way through a 1-year assignment aboard the ISS. The “normal” assignment for each of the 6-person crew is six months, or less.

Best ISS photo

Photo (and added flags) by NASA
Interior Exploration Using Seismic Investigations, Geodesy, and Heat Transport (InSight): A robotic MARS lander scheduled for launch in 2016 that will investigate the interior (geophysical) processes that formed Mars’s core, mantle, and crust, comparing these processes to the Earth. In addition, InSight will also investigate seismic and meteorite impact rates on Mars.

Low Earth Orbit (LEO): An orbit around Earth with an altitude between 160 kilometers (99 mi) (orbital period of about 88 minutes), and 2,000 kilometers (1,200 mi) (with an orbital period of about 127 minutes).

Lunar Reconnaissance Orbiter (LRO): A Moon orbiter currently in operation at Earth’s Moon.

MOXIE: A small experimental ISRU device that extracts Oxygen from carbon dioxide (CO2 in a process called “solid oxide electrolysis”. MOXIE will be tested on the ISS and will be a part of the 2020 rover. Full size versions of MOXIE will be sent to Mars ahead of manned flights to produce and store oxygen to be used by the astronauts when they arrive, and during their stay on the surface of Mars as well as on the Mars Return Vehicle (MRV).


(Graphic from NASA via Wikipedia)

National Aeronautics and Space Administration (NASA)

Solar Electric Propulsion (SEP): A type of rocket engine that uses solar power from solar panels to accelerate ionized propellant (plasma) for thrust. These engines do not produce as much thrust as chemical engines, but they are much more efficient, allowing much more mass to be transported with far less fuel. This type of engine was used for NASA’s Dawn Mission which sent an orbiting robot to asteroids Vesta and Seres (This was the first ever mission that visited and orbited two different asteroids).

The drawing, below, shows an unmanned cargo carrying SEP vehicle on its way to Mars

Solar Electric Propulsion
Space Launch System (SLS): NASA defines the SLS as “Orion’s ride to deep space”.

Arguably, the most interesting and exciting item for the Journey to Mars is the SLS rocket, which will be the largest and most powerful rocket ever built.

SLS is actually three different versions of the rocket that will eventually take the Orion spacecraft and 4 astronauts to MARS. The third and final version of SLS will be capable of launching 130 metric tons into space. Nasa has it’s own way of naming things, so these three versions of the SLS are called Block 1, Block 1B, and Block 2.

[] SLS Block 1 will support the first exploration mission into circumlunar space. This unmanned test flight, planned for 2018, will be the first integrated test of SLS and the Orion spacecraft. This mission is called Exploration Mission 1 ( EM-1 )

[] SLS Block 1B will add an expanded upper stage. Exploration Mission 2 (EM-2) will be manned and will test and validate key operational capabilities that are required to become Earth Independent.

[] SLS Block 2 will add advanced boosters (the largest and most powerful solid fuel rockets ever built) to replace the original boosters used versions 1 and 1B. This third and final version of the SLS rocket will be used for testing deep space habitats, an Asteroid Return Mission (ARM) and eventually manned missions to Mars.

Shown, below, is a part of the SLS where the four RS25 main engines attach to the rocket on the adapter to the left (white) and the bottom section of the Core Stage on the right (yellowish). This structure has passed all preliminary tests and is ready to be assembled to the rest of the rocket.

SLS Core Structure Lower Section

Below is a photo of SLS Block 1 on its way to the launch pad for initial integration testing. This test will NOT actually launch the rocket. That tiny little cone shaped thing on top is an Orion Space Craft where astronauts can ride, but not for this unmanned, no launch test . . .

SLS for TDandA post. . . and here is an alternate view looking down from the top showing the Orion spacecraft.

ORION atop Block 1
And, that’s all I have ready for prime time right now.

Not sure what will be next, but I have a couple of things in the works.

Take care, and visit the NASA website often – – they have TONS of wonderful stuff there, including NASA TV from the ISS.  No – – its not all “live” – – lots of reruns because there is simply not that much visually exciting stuff happening on the ISS – unless you like watching astronauts do household chores, ISS maintenance chores, and scientific research. Scientific research and maintenance chores are very important, but they don’t make “good TV”.


About w6bky

Retired 29 May 1987. Now do hobbies: blogging, ham radio, gardening, etc.
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2 Responses to Terminology, Definitions and Acronyms

  1. john zande says:

    That’s a big rocket, would love to see it lit 🙂


  2. w6bky says:

    Another JTM comment from John.

    Yes, John, it is a r-e-a-l-l-y B-I-G rocket !

    In fact, the SLS Block 2 (the third version of the STS) may well be the largest chemical rocket that will ever be built.


    Because there is a point where chemical rockets no longer make much sense. The larger the rocket, the more fuel you must burn in order to get the thing off the launch pad = diminishing return for the cost of building and FUELING the rocket. Looking at the Core section of the SLS rocket, almost all the fuel from those two huge fuel tanks is spent in the first two minutes to simply get the structure and the unused fuel off the pad and on its way to orbit. . . . and so it goes until all the fuel is gone and the boosters detaches, then the core section is ejected, and then second stage rocket engine takes over to power the “payload” into orbit.

    As you probably already know, the Indian Space Research Organization (ISRO) have a satellite orbiting Mars. What you may not know is, that the rocket they used to get satellite there was small compared to the rockets we have used to get our orbiters, landers, and rovers to Mars. I found some information about the ISRO Mars Orbiter on – a summary is shown below:

    [] Mass: The total lift-off mass was 1,350 kg (2,980 lb), including 852 kg (1,878 lb) of chemical propellant.

    [] Bus: The spacecraft’s bus is a modified structure and propulsion hardware configuration, similar to India’s lunar orbiter that operated from 2008 to 2009, with specific improvements and upgrades needed for a Mars mission.
    [] Power: Solar panels can generate a maximum of 840 watts of power in Mars orbit.
    [] Orbiter Propulsion: A liquid fuel engine with a thrust of 440 newtons is used for insertion into Mars orbit. The orbiter also has eight 22-newton thrusters for attitude control. Its propellant mass is 852 kg.

    How did they do it?

    They used GRAVITY power ! . . .

    The rocket was put into an elongated orbit around the Earth and with each of 5 orbits the rocket was guided into an even more elongated orbit, and on each orbit the gravitational “slingshot” effect added more speed. At the end of the fifth orbit the rocked was guided to the point where Mars would be months later at which time instructions would be sent to guide the satellite into orbit around Mars. There is, of course, lots of complicated math and timing in order to make all this happen, but that’s the general outline of how it was done.

    NASA used “slingshot” gravity assist to help get the New Horizons probe to Pluto using a close encounter with Jupiter to pickup the “free” speed boost. The Jupiter boost also cut about 6 months off the travel time.

    I’m sure that’s more that enough for now !

    Take care.


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