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#1 2017-02-27 21:14:30

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,141

Space Acronyms

I think that this is one topic that we can all add to in order to help us all talking the same language....

The following acronyms for hardware elements are referred to in this architecture.
The use of MLLV (Medium Lift Launch Vehicle) or EELV (Evolved Expendable Launch Vehicle) to eliminate the significant investment required to develop a suitable HLLV (Heavy Lift Launch Vehicle)

The use of biconic spacecraft to improve EDL (Entry, Descent and Landing) performance and better optimise spacecraft.

H2M (Humans to Mars)
ISPP (In Situ Propellant Production)
LOX/LCH4 (liquid oxygen/liquid methane)
DRA (Design Reference Architecture)
COTS (Commercial Off-The-Shelf)
MTV (Mars Transfer Vehicle)
MAV (Mars Ascent Vehicle)
DAV (Descent/Ascent Vehicle)
MCM (Mars Cargo Module)
MSH (Mars Surface Habitat)
MTV (Mars Transfer Vehicle)
SOP (Standard Operating Procedure)
MSL (Mars Science Laboratory)
EOI (Earth Orbit Insertion) or (Earth Orbit Injection)
TMI (Trans Mars Injection)
MOI (Mars Orbit Injection)
LEO (Low Earth Orbit)

I hope this is a good start for others to join in and add to this list.

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#2 2017-02-28 09:24:29

louis
Member
From: UK
Registered: 2008-03-24
Posts: 4,896

Re: Space Acronyms

ISRU - In situ resource utilisation.
LMO - Low Mars Orbit
PV - Photovoltaic
MCT - Mars Colonial Transporter


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#3 2017-02-28 09:27:43

louis
Member
From: UK
Registered: 2008-03-24
Posts: 4,896

Re: Space Acronyms

Oh and -

RTG - Radioisotope Thermoelectric Generator

RPS - Radioisotope Power System


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#4 2017-02-28 11:12:42

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,643
Website

Re: Space Acronyms

Many thanks.  Now maybe I can sort through all the gibberish I run into. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#5 2017-02-28 23:01:39

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,141

Re: Space Acronyms

High Ballistic Co-effiecient (rigid) Aero-shell Technology (HBCAT)
Low Ballistic Coefficient Aeroshell Technology (LBCAT)
Adaptable, Deployable Entry and Placement Technology (ADEPT)
Nuclear Electric Propulsion (NEP)

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#6 2017-03-02 00:51:17

kbd512
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Registered: 2015-01-02
Posts: 2,957

Re: Space Acronyms

Here are a few more for the list (a couple aren't acronyms, but referred to often enough to warrant an explanation):

Rocketry
dV - Delta-V (Delta is a Greek language pictogram used to represent a difference between two numerical values in mathematics, and as it pertains to rocketry it refers to a change in velocity, relative to an initial or starting velocity, which is represented by the English language letter "V"; this concept is important in rocketry because a given velocity delta or change requirement is used to calculate how much fuel a rocket requires to produce the required change in velocity)
Isp - Specific Impulse (another important rocketry concept to understand that represents fuel economy in rockets; denotatively specific impulse is the total impulse or momentum delta produced by the rocket's propellant per unit of propellant consumed and is equal to thrust produced divided by propellant consumption rate, and since there is a time component involved specific impulse is measured in seconds)
Density Impulse - a derivative of specific impulse and propellant average specific gravity (a measurement of the total impulse or momentum delta that a unit volume of propellant can produce, denotatively density impulse is the specific impulse multiplied by the average specific gravity of the propellant, or propellants, when separate fuel and oxidizer are used; LOX/LH2 has the highest specific impulse of any common bi-propellant used in rocketry, but density impulse is the lowest of any common bi-propellant combination as a result of the low specific gravity of the hydrogen fuel)

NASA Administrative Reports and Executive Briefings
VSE - Vision for Space Exploration (a master plan for achieving NASA's space exploration objectives)
ESAS - Exploration Systems Architecture Study (mission planning and trade studies reports published by NASA)
TRL - Technology Readiness Level (ratings TRL1 through TRL9 are associated with maturity levels of technologies developed by or for NASA)

NASA Human Space Flight Related
STS - Space Transportation System (also known as the Space Shuttle Program)
SRM / SRB - Solid Rocket Motor / Solid Rocket Booster (refers to the large white solid rockets attached to the STS and SLS LOX/LH2 fuel tank)
SLS - Space Launch System (STS-derived rocket technology redesigned into a super heavy lift class rocket)
EUS - Exploration Upper Stage (upper stage for SLS, that sits atop the LOX/LH2 tank, designed for delivering payloads beyond Earth orbit)
EAM - Exploration Augmentation Module (a multipurpose pressurized storage spacecraft supporting human space exploration activities)

NASA Space Flight Activities
KSC - Kennedy Space Center (part of the Cape Canaveral Air Force Station)
NTD - NASA Test Director (the person responsible for a rocket launch activity)
MCC - Mission Control Center (the place where space flight activities are directed from)
LCC - Launch Commit Criteria (the specific circumstances under which a rocket launch activity will be permitted to proceed)
GLS - Ground Launch Sequencer (automated program that controls launch-related activities during the countdown to a rocket launch)
RSLS - Redundant Set Launch Sequencer (the computers aboard the rocket that the GLS eventually hands off partial launch sequence control to)
RSO - Range Safety Officer (the person who is responsible for activation of the self-destruct mechanisms attached to a rocket when the rocket malfunctions in a way likely to harm people on the ground if it is not destroyed)

NASA JPL (Jet Propulsion Laboratory) Related
MSL - Mars Science Lab; includes the RTG-powered Curiosity rover on Mars and the orbital satellite in Mars orbit
HIAD - Hypersonic Inflatable Aerodynamic Decelerator (a stack of inflated fabric donuts with a heat shielding fabric wrapped over the donuts; typically attached to something you don't want incinerated if it enters a planetary atmosphere at orbital velocity)
MOLA - Mars Orbital Laser Altimeter (a precise light beam measurement instrument used to determine height or altitude above the surface of Mars)

SpaceX
ITS - Interplanetary Transport System (interplanetary colonization class rocket)
FH/F9H - Falcon Heavy (heavy lift class rocket that uses 3 Falcon 9 first stage boosters and 1 Falcon 9 upper stage)
F9 - Falcon 9 (orbital class rocket)
OCISLY - Ocean going robotic landing platform for recovery of Falcon 9 first stage boosters christened Of Course I Still Love You
JRTI - Ocean going robotic landing platform for recovery of Falcon 9 first stage boosters christened Just Read The Instructions

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#7 2017-03-02 06:20:39

louis
Member
From: UK
Registered: 2008-03-24
Posts: 4,896

Re: Space Acronyms

Thanks kbd - very helpful.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#8 2017-03-04 10:07:17

Void
Member
Registered: 2011-12-29
Posts: 3,011

Re: Space Acronyms

Elon Musk created;

ASS

"Acronyms Seriously Suck"

smile

It is in the new book about him.
He demanded that his employees stop creating Acronyms.

https://plus.google.com/+TheSpaceXFanCl … KzSoTimHEH
Quote:

Acronyms Seriously Suck (ASS Rule)
May 2010 email from Elon Musk to All@spacex
"There is a creeping tendency to use made up acronyms at SpaceX. Excessive use of made up acronyms is a significant impediment to communication and keeping communication good as we grow is incredibly important. Individually, a few acronyms here and there may not seem so bad, but if a thousand people are making these up, over time the result will be a huge glossary that we have to issue to new employees. No one can actually remember all these acronyms and people don’t want to seem dumb in a meeting, so they just sit there in ignorance. This is particularly tough on new employees.

That needs to stop immediately or I will take drastic action—I have given enough warnings over the years. Unless an acronym is approved by me, it should not enter the SpaceX glossary. If there is an existing acronym that cannot reasonably be justified, it should be eliminated, as I have requested in the past.

For example, there should be no “HTS” [horizontal test stand] or “VTS” [vertical test stand] designations for test stands. Those are particularly dumb, as they contain unnecessary words. A “stand” at our test site is obviously a test stand. VTS-3 is four syllables compared with “Tripod,” which is two, so the bloody acronym version actually takes longer to say than the name!

The key test for an acronym is to ask whether it helps or hurts communication. An acronym that most engineers outside of SpaceX already know, such as GUI, is fine to use. It is also ok to make up a few acronyms/contractions every now and again, assuming I have approved them, eg MVac and M9 instead of Merlin 1C-Vacuum or Merlin 1C-Sea Level, but those need to be kept to a minimum."

I guess for me, I could vouch for "LEO" as something that people in general could learn here.
But creating a special vocabulary to exclude the unfamiliar will have a specific effect.  I guess it will be up to you guys what kind of a web site you want and for who.

Spacenut.  Feel free to delete this post when you are done with it.  I don't need to have it here, I really don't care.

Last edited by Void (2017-03-04 10:14:01)


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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#9 2017-03-04 15:16:37

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,790
Website

Re: Space Acronyms

kbd512 wrote:

dV - Delta-V (Delta is a Greek language pictogram used to represent a difference between two numerical values in mathematics, and as it pertains to rocketry it refers to a change in velocity, relative to an initial or starting velocity, which is represented by the English language letter "V"; this concept is important in rocketry because a given velocity delta or change requirement is used to calculate how much fuel a rocket requires to produce the required change in velocity)

All true. The Greek letter delta has changed over time. The capital letter is drawn as a triangle, lower case has changed more significantly. One drawing of lower case delta looks vaguely like the English lower case "d", and since it has the same sound is sometimes used.
Δ - capital Delta, δ - lower case delta. These are fonts that show in your browser. An image with larger view that explains why lower case is thought to look like "d".
100px-Delta_uc_lc.svg.png

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#10 2017-03-05 20:40:04

kbd512
Moderator
Registered: 2015-01-02
Posts: 2,957

Re: Space Acronyms

Rob,

Thank you for providing a visual of the "delta" pictogram.

I feel I should add a few more definitions to more fully explain what affects these rockets that we're so interested in here.

Speed - a scalar value, a measure of how far an object travels for a given unit of time, independent of direction
Velocity - a vector value, a measure of how far an object travels in a given direction for a given unit of time, with respect to an initial or starting position; frequently incorrectly used interchangeably with speed (I've probably done it somewhere in this post, even though I understand the difference)
Acceleration - a vector value, a measure of the rate of change in velocity change or velocity delta; in or near Earth's gravity well, this is understood to be approximately 9.8m/s^2; constant acceleration from gravity is a concept famously illustrated by one of our moon walkers when he dropped a feather and a hammer on the moon, whereupon both objects were equally accelerated by gravity and hit the surface of the moon at the exact same time

In rocketry, velocity measures the rate of change of the position of a rocket traveling in a given direction, relative to its initial position and initial velocity.  Anyone merely sitting on the surface of the Earth, staring up at the sky and wondering about the mysteries of the universe, is already moving through space at fantastic velocity, relative to our Sun.  Relative to a given point on the surface of the Earth, your velocity delta is zero.  Even so, you're moving through space around our Sun many times "faster than a speeding bullet", at approximately 108,000km/hr or 30km/s.  Try not to let all this speed go to your head, though, Superman.  A bullet fired from a M16 rifle, with its comparatively paltry muzzle velocity of 1km/s is still traveling at approximately 31km/s.  Therefore, intercepting the flight path of that bullet when its velocity vector, or velocity delta, is substantially variant from your own, is still a very bad idea.

In an attempt to illustrate a common use of these speed, velocity, and acceleration concepts in rocketry, consider the rotational velocity of the Earth at varying points on the Earth.  That is how fast you're spinning around Earth's own axis of rotation, as opposed to the speed at which we orbit our Sun.  At the equator, this is approximately 1670km/hr at the equator and approximately 1180km/hr at 45 degrees latitude (north or south), counter-clockwise, as viewed from the North Star.  If you're at the equator, you're already moving 490km/hr faster than you are if you were at 45 degrees north or south latitude.  Assuming you launch in the same direction of rotation as the Earth, this higher initial starting velocity provides a very real assistance to achieving orbital velocity since less acceleration is required to achieve orbital velocity, nominally 7.726km/s.  That 7.726km/s orbital velocity value (here's an example here where I used the word "velocity" incorrectly since I failed to provide a direction- 7.726km/s counter-clockwise around the Earth, for example) is the velocity at which you're traveling radially outward as fast as gravity is pulling you back inward towards the surface of the Earth.  The end result of equatorial launches into the direction of the Earth's rotation is that your rocket either requires less fuel to achieve orbital velocity, which means the rocket can be slightly smaller and therefore less expensive to manufacture, or it can carry more payload, which is the most common way in which launching rockets from pads nearer to the equator is used to our advantage.

Layman's Takeaway:
1. If you have to accelerate less to achieve sufficient velocity to get to where you want to go, then a rocket with invariant Isp (gas mileage for rockets) requires less fuel or can carry more payload.
2. If you have to accelerate more to achieve sufficient velocity to get to where you want to go, then a rocket with invariant Isp (gas mileage for rockets) requires more fuel or can carry less payload.
3. Rockets are designed to deliver a given mass of payload with a given mass of fuel.  Within certain limitations, the mass of the fuel and payload can be altered to deliver the payload.  However, those limitations are very restrictive and any substantial variance in the mass of the fuel, payload, or the rocket itself typically requires designing and building a new rocket to achieve the performance desired.
4. The extreme performance requirements of rockets make them incredibly expensive.  To understand just how extreme the performance requirements are, consider that internal combustion engines in typical passenger vehicles deliver .5hp to 1hp per pound.  F1 cars make more horsepower than typical passenger cars, between 3hp and 4hp per pound, but those engines are completely rebuilt after individual races.  The Space Shuttle Main Engine (SSME) are required to deliver 1,543.4hp per pound.  Imagine how much more difficult it would be to design an engine capable of producing roughly 440 times as much power as F1 cars make.  Jet engines don't come close to the level of power output that rocket engines are routinely expected to achieve, as demonstrated by the remarkable Pratt & Whitney F135 afterburning turbofan that powers the F-35 "only" produces 29,000 shaft horsepower at maximum rated power and has a power-to-weight ration of 7.73hp per pound.  Rocketry isn't just a different ball game, it's not even the same sport.
5. Weight is the mortal enemy of the rocket and therefore, the rocket scientist.  We have examples of other engines that produce 12,000,000 horsepower, but they're the size of small buildings and weigh nearly as much as small buildings.  The SSME weighs as much as a fully loaded Ford F-350, but you would need 27,273 6.7L Power Stroke Turbo Diesels from the 2017 F-350's to produce equivalent horsepower to the SSME and those engines would weigh 30,000,300 pounds (including engine oil), which is a little more than what 4.5 fully fueled Saturn V rockets weigh.  If we opted for the high performance Pratt & Whitney F-135's, instead, then we'd need 414 and they'd weigh 1,552,500 pounds.
6. The $72,000,000 purchase price paid for each SSME (Aerojet-Rocketdyne model RS-25) is pretty reasonable when you consider that 414 F-135's cost $5,382,000,000 and 27,273 6.7L Power Stroke Turbo Diesels cost $272,730,000.  However, cost is relative to performance.  When you want something that has the level of of performance of the SSME, you're gonna pay dearly for it.  Nearly every aspect of space flight demands "in extremis" performance from every component of every system making it possible.  The method of transportation used to get to space, the rocket, is no exception.  Speed costs money.  How fast do you wanna go?
7. Rockets are fun to watch when they work properly, but it takes a lot of hard work and dedication to make them work.  No matter how "easy" it looks on TV, rest assured that it is not.  There's nothing else that we do that's quite like space travel.

Anyway, I hope this helps someone out there understand a little more about this rocketry business that we're all so fascinated with here.

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#11 2017-05-19 19:52:52

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,141

Re: Space Acronyms

From kbd512:

BNNT = Boron-Nitride NanoTube

NASA is adding extra Hydrogen to BNNT's for GCR protection.  It's the lightest and best performing GCR blocker known to science, thus far.  It's good at stopping Solar Particle Events (SPE's), too.

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#12 2017-06-25 18:54:18

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 16,141

Re: Space Acronyms

ΔV                   delta-velocity                   
CARD          Constellation Architecture Requirements Document
CEV            Crew Exploration Vehicle
CLV            Crew Launch Vehicle
EDS            Earth Departure Stage
EG              Aeroscience and Flight Mechanics Division (organization code)
EI                    Earth  Interface                   
EOLO              Earth Orbit to Lunar Orbit
ESAS              Exploration  Systems Architecture Study
FAM               Functional  Area Manager               
IAU               International Astronomical Union
JSC               Johnson Space Center
LAN               Longitude of the Ascending Node
Lat               Latitude                   
LDO                Lunar Destination Orbit
LEO                Low Earth Orbit
LLO                Low Lunar Orbit
LOEE              Lunar Orbit to Earth Entry
LOI                 Lunar  Orbit  Insertion                 
Lon                  Longitude                 
LS                   Landing  Site                   
LSAM               Lunar Surface Access Module
NASA              National Aeronautics and Space Administration
SBU               Sensitive But Unclassified
TCM               Trajectory Correction Maneuver
TDS                Task Description Sheet
TEI                  Trans-Earth  Injection                 
TLI                  Trans-Lunar  Injection

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#13 2017-07-08 15:30:22

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 16,141

Re: Space Acronyms

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#14 2017-07-28 19:41:31

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,141

Re: Space Acronyms

  • delta-v     change in velocity
    g             gravity, 1g corresponds to gravity at the surface of the Earth
    ELEO        Equatorial Low Earth Orbit
    GCR         Galactic Cosmic Rays
    HEO         High Earth Orbit
    ICRP         International Commission on Radiological Protection
    ITS           Interplanetary Transportation System
    kg             kilogram
    L2             Lagrange Point Two
    L5             Lagrange Point Five
    LEO           Low Earth Orbit
    m              meter
    mGy           milli-Gray
    MPA           megaPascal
    mSv           milli-Sievert
    NEO           Near Earth Object
    rpm            rotations per minute
    SSP            Space Solar Power
    T               metric ton

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#15 2018-07-10 00:48:06

kbd512
Moderator
Registered: 2015-01-02
Posts: 2,957

Re: Space Acronyms

IVF - Integrated Vehicle Fluids

IVF was created by United Launch Alliance (ULA) as an integrated power and propulsion system for the upper stages of rockets.  The system uses a small piston driven internal combustion engine that consumes minor quantities of propellants from the main propellant tanks of the rocket stage to provide pressurization control for propellant tanks to eliminate the requirement for separate high pressure inert gas tanks to re-pressurize the main propellant tanks, electrical power for communications and navigation avionics, thermal stabilization of cryogenic propellants, and attitude control using gaseous boil-off or siphon-off of the cryogenic propellants.

The APU (Auxiliary Power Unit) in the Space Shuttle orbiter burned NTO/MMH from the reaction control system tanks to provide electrical power to the avionics and life support systems during the atmospheric phases of ascent and descent.  IVF is the same concept, but using inherently higher Isp cryogenic propellants.  It would be like a Space Shuttle APU that burned LOX/LH2 from the external tank.  It's a form of universal APU for rocket stages that requires a lot less plumbing and wiring than entirely separate systems that provide electrical power for avionics, propellant tank pressurization, and reaction control systems.

ULA has designed the piston combustion engine part of the IVF system specifically to use the LOX/LH2 that feeds their Aerojet-Rocketdyne RL-10 powered upper stages, but it works equally well with LOX/LCH4 (also tested) or LOX/RP-1 (not tested, since we can very confidently say that combustion engines can burn oxygen and high quality kerosene).  The implementation details specify a small and lightweight 6 cylinder aluminum engine adapted from a race car engine that's connected to an electric generator and pump accessories to recirculate and pressurize / de-pressurize the propellant tanks, gaseous O2/H2 accumulation tanks that feed the piston engine and the O2/H2 reaction control system.

The principle advantages of IVF are as follows:

1. short to medium duration (days to a few months) storage of cryogenic propellants through tank depressurization and active cooling by powering a cryocooler
2. no highly pressurized inert gas (Helium or Nitrogen) tanks required to re-pressurize the main propellant tanks prior to subsequent burns or thrusting periods using the stage's main engine (typically done for orbital injection or orbital plane changes)
3. no separate reaction control systems using toxic and hypergolic (oxidizer and fuel explode on contact with each other) storable chemical propellants (NTO oxidizer and MMH or other Hydrazine fuel blends, or more recently the less toxic but still corrosive "green" AF-M315E storable Hydrazine monopropellant substitute) and their associated ground handling hazard issues and costs associated with loading the propellants into the rocket)*
4. for mission planners, a simple mathematical equation dictates the vehicle's remaining delta-V performance capabilities based upon it's current propellant load
5. greatly reduced overall system mass and complexity

* Notes:
It's extraordinarily expensive to load Hydrazine fuels since propellant loading is a very intricate operation that mandates special storage and handling procedures for such highly reactive and lethal chemicals.  We've mastered Hydrazine storage and handling procedures over many decades of use, but mistakes still happen whenever humans are involved.  The results typically range from very expensive to serious injury and death from chemical or thermal burns.  This is always possible with any rocket propellant combinations, as all rocket propellants are extremely powerful explosives.  However, hypergolic propellants represent a particularly severe hazard to contend with since they were engineered to explode on contact with each other.  Unfortunately, they can also react violently with other substances present in rocketry facilities.

The advantage provided by #5 is huge in the world of low-Isp chemical rockets and #4 is a close second.  The simplified systems design requirements, lower subsystem masses, and less onerous propellant handling procedures are just added bonuses.  The confluence of advantages are what drove the creation of IVF.  When a computer with less processing power than a cell phone can tell you exactly what maneuvers you can perform with your remaining / available propellant load, you can easily determine what you can or can't do with a given payload mass once you're in orbit.  The concept is not new at all, but it's never been done before because the technologies that make an integrated power and propulsion solution possible weren't considered to be mature and reliable enough.  That's all changing rather rapidly.

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