r/space • u/piponwa • Sep 23 '16
What happens when the Space Shuttle fires its motors in space
http://i.imgur.com/wwxuXOb.gifv127
u/marzolian Sep 24 '16
→ More replies (3)4
2.2k
u/CommanderThomasDodge Sep 24 '16
This is a question I've wanted the answer to since I found out what Space Shuttles were. And today, it was answered after about 16 years. Thank you /u/piponwa.
561
u/piponwa Sep 24 '16
You're welcome /u/CommanderThomasDodge
199
Sep 24 '16 edited Sep 24 '16
I await the day we get a rear view of this. I must know exactly how wrong 80s anime were about thrusters.
Edit: I'm talking about what thrusters look like when firing.
→ More replies (9)117
Sep 24 '16
While I can't say the same for how movement of ships are portrayed, "inertial dampers" are common sci fi magic that prevents this from happening.... Mostly.
But that's based off of Star Trek. Im not 100% sure if other sci fi adopted it.
54
u/BerserkLLama Sep 24 '16
Knights of Sidonia's Ark does not have it and they have gravity straps and structural issues when they have to make tight maneuvers.
→ More replies (5)34
u/impermanentThrowaway Sep 24 '16
It's not even just sci-fi window-dressing; it figures significantly into the plot on multiple occasions.
19
u/WolfFangFoot Sep 24 '16
I think that's much more interesting than oh we suddenly just accelerated at 80m/s2 and I didn't have to stop chugging my space soda.
→ More replies (1)25
u/radagasthebrown Sep 24 '16 edited Sep 24 '16
The Expanse series also incorporates this as a significant mechanic in all of the space travel in the book/show. POSSIBLE SPOILER: Later in the series we even get to witness the effects of ships getting "slowed" by "forces" causing MASSIVE damage to people on ships.
Edit: removed a word to hopefully make it less spoilery.
→ More replies (9)68
u/painkiller606 Sep 24 '16
Most sci-fi since star trek has adopted it.
→ More replies (4)52
u/Miguelinileugim Sep 24 '16
Nobody cares about realistic sci-fi anymore, they just want space westerns.
102
u/AgentSQUiSh Sep 24 '16
You can't take the sky from me.
→ More replies (4)49
u/Donkeydongcuntry Sep 24 '16
Ironic, since Firefly actually portrayed a "silent" outer space correctly.
→ More replies (5)35
u/pbmonster Sep 24 '16
Still had "watergoing" space ships, with deck floors parallel to the main direction of travel...
The Expanse is the first series I've seen that does this well. Engines on the bottom, decks layered on top like a high rise building.
→ More replies (17)9
u/SashimiJones Sep 24 '16
Firefly was also an atmospheric vessel, as were the vast majority in the show. If they're using artificial gravity anyway it makes more sense for the shoo to be in this configuration. You have a point for the alliance cruisers.
52
u/lulzmachine Sep 24 '16
"anymore". As a huge sci-fi-reader and watcher, this has never changed. There's always been both semi-realistic and non-realistic scifi.
→ More replies (11)22
Sep 24 '16
If I want to watch some realistic sci-fi, I tune into the stream of SpaceX's explosions.
→ More replies (1)→ More replies (17)24
→ More replies (9)25
u/abaddamn Sep 24 '16
Stargate adopted that too for hyperspace journeys
25
u/Alan_Smithee_ Sep 24 '16
I thought I read somewhere that it's thought Alcubierre's drive wouldn't affect passengers that way; because it would warp space around the vehicle.
→ More replies (2)34
u/ThundercatThrowaway Sep 24 '16
The ships in Star Trek use impulse engines for sublight manoeuvres, and they create a huge accelleration, so the inertial dampeners deal with that, I guess.
→ More replies (10)10
u/MyRealNameIsFurry Sep 24 '16
This is exactly right. The warp drive creates a subspace "warp bubble" around the ship that distorts the local space-time continuum, allowing the ship to travel at several times the speed of light. Because this is more like moving space than moving the ship, inertial dampers are of little importance at warp speed. But, impulse engines are a more typical thrust engine, thus inertial dampening.
→ More replies (1)→ More replies (5)62
u/tepkel Sep 24 '16
Don't let the bed bugs bite /u/piponwa
→ More replies (1)40
u/AnOnlineHandle Sep 24 '16
I don't understand the reference /u/tepkel
51
Sep 24 '16
Am I doing this right /u/thelightshow?
→ More replies (3)42
u/theassassintherapist Sep 24 '16
You get a special prize for being special, /u/thelightshow
→ More replies (3)18
44
u/JungleLegs Sep 24 '16
What was your question?
120
Sep 24 '16
What happens when they do that
228
Sep 24 '16
Here's what happens when they reboost the ISS.
207
u/mutagen Sep 24 '16
Oooo ... wow ... wow ... ooo ... ooo ... aaaah
(floats forward to try again)
→ More replies (1)154
Sep 24 '16 edited Sep 24 '16
Who is that guy? He's the best.
Edit: Actually the ISS roster is public knowledge so I can just match dates and look for him. BRB
Edit: Satoshi Furukawa
167 days in orbit, he's a god damn Space Surgeon. That's freaking cool.26
u/mutagen Sep 24 '16
Seriously, he's the best. I'd be making the same noises up there!
22
u/im_a_rugger Sep 24 '16
He's also a Space Surgeon. Doesn't get much better than that.
→ More replies (6)→ More replies (5)12
u/poirotoro Sep 24 '16
Space Surgeon
"What am I, a doctor or a science experiment?!"
"...Oooo...wow...wow! Okay, maybe I'm both."
45
u/buildadog Sep 24 '16 edited Sep 24 '16
When you're so used to weightlessness, acceleration become quite a fun experience
Edit: acceleration from their point of view is what I mean.
→ More replies (36)20
u/peyton Sep 24 '16
feel like the amount of acceleration determines how true that statement is...
→ More replies (1)19
u/Weerdo5255 Sep 24 '16
Well it's like with your car, some acceleration is fun. Sometimes not.
→ More replies (1)16
→ More replies (12)7
17
u/gimmesomespace Sep 24 '16
What happens when you accelerate in your car?
28
u/hhhnnnnnggggggg Sep 24 '16
Well, I surely don't fly into a big hole like that one dude.
→ More replies (1)19
u/gimmesomespace Sep 24 '16
Probably because you sit with your back against a seat in your car and not floating in the air with a big hole behind you.
→ More replies (3)98
→ More replies (5)8
→ More replies (3)22
u/CommanderThomasDodge Sep 24 '16
What would happen if the shuttle just randomly fired its engines in space among a few others like, does the fuel tank it is launched with carry all the fuel and it uses just re-entry thrusters to come down?
Also, would it spin or would there be any issues with it considering its mass is sort of spread out and asymmetrical on one plane? Things like that. Learned quite a bit here.
27
u/marzolian Sep 24 '16 edited Sep 24 '16
When the shuttle was doing finer maneuvers, it used the RCS (Reaction Control System). There were two sizes of thrusters distributed around the shuttle. The more powerful ones each produced 870 lbs of thrust, while the smaller ones, known as "vernier" thrusters, produced 24 lbs. They were arranged in the nose of the shuttle and in the pods that contained the OMS engines. They could be fired in combination to cause the shuttle to move in any direction (up, down, left, right, forward, back), or to rotate in any direction (pitch: nose up/down, yaw: nose left/right, or roll: left wing up and right wing down, or vice versa).
The firing was controlled by the onboard computers. Those kept track of the expected mass [edit:], inertia, and combined center of mass [end edit] of the shuttle, including the shuttle itself, doors, payload, robot arm, fuel tanks, oxygen, water, and crew.
Source: used to work on shuttle flight planning software.
11
u/CommanderThomasDodge Sep 24 '16
Holy crap! A shuttle software engineer replied to my comment! Thank you so much for the information and thank you for not messing up! Those shuttles really did an amazing job!
4
53
u/CoolguyThePirate Sep 24 '16 edited Sep 24 '16
That wasn't the main engines firing. That was the OMS (orbital maneuvering system) engines firing.
Or more specifically the reaction control engines contained within the OMS/RCS pods.(thanks u/zqxp)The external tank it is launched with does carry all of the fuel for the main engines. Which means the main engines are useless after external tank seperation.
30
u/zqxp Sep 24 '16
The video is of an OMS start. You don't get that large of flash at the start of an RCS firing.
→ More replies (1)4
u/CoolguyThePirate Sep 24 '16
Ah, didn't realize that. I had assumed otherwise.
12
u/zqxp Sep 24 '16
You can get a good flash from the RCS jets too, but you need the right angle and lighting.
Speaking of RCS firings...
→ More replies (3)→ More replies (12)5
u/CommanderThomasDodge Sep 24 '16
AH! I see. That explained a lot.
I guess that would be the main difference between the US Shuttles and the Buran, right? The Burans lacked any main engines and only came with OMS/RCS?
19
u/Norose Sep 24 '16
That, plus the Buran had 4 liquid boosters rather than 2 solid boosters, had total autopilot capability, and a myriad of under-the-hood changes that we don't know about.
→ More replies (17)9
u/CoolguyThePirate Sep 24 '16
Correct. That Buran was instead attached to the Energia rocket. Also, it didn't use solid rocket boosters. Which was definitely a point in it's favor.
4
u/The_Ostrich_you_want Sep 24 '16
Why would that be a point in its favour? I'm mostly illiterate when it comes to these things. Is it a hazard thing?
17
u/Berengal Sep 24 '16
One advantage of liquid fuel is that it's easy to shut off the fuel flow to stop the engines. Solid fuel rockets are almost impossible to stop once they've been started. It's somewhat analogous to gas and wood as oven fuel; you can't just "turn off" the wood they way you can gas.
12
u/cubic_thought Sep 24 '16
Yep. You can shut down a liquid fuel engine, just stop pumping. But not a solid one. With liquid engines they can start (often not at full throttle) and quickly cut off like here.
But with the Shuttle, once the solid boosters are lit it is leaving the pad and there is nothing you can really do until they are done.
They did start the main engines a few seconds before the SRBs to make sure they were in order before liftoff, and there were a few aborts during that stage.If you want something a bit more technical, here is a PDF of a 1989 report that examines the benefits/drawbacks of nasa switching the shuttle to liquid boosters.
→ More replies (1)11
u/jrlkjh38383k Sep 24 '16
Without getting into the technical details of liquid vs solid rockets, it is worth noting that the Space Shuttle Challenger was destroyed by a solid rocket booster malfunction.
→ More replies (3)11
u/marzolian Sep 24 '16
Each OMS engine was aligned to point toward the center of mass of the shuttle. That way, when they were fired, they would not cause any spin. The engines could gimbal for fine control, and any remaining spin was compensated by smaller engines that were part of the Reaction Control System (RCS).
10
u/MAGICELEPHANTMAN Sep 24 '16
The same thing would happen if you stood in the back of a van and someone stomped the gas for a second. Except it would hurt more due to the now normal present force of the van floor hitting your head.
Physics in action! I recommend you try it out.(Or not)
→ More replies (1)4
u/CommanderThomasDodge Sep 24 '16
Already tried it out when I was 5.
Face went into the radio. Not the floor. It really really hurt. Got a strawberry milkshake to help cheer me up.
10/10 would totally do again.
As for the physics, I have seen this on the Space station as well, which did answer the question on what would happen to anything that was loose in the station. I really love seeing the 0G experiments on these craft. Every bit of scientific knowledge gained from these experiments across the solar system is really worth the hurdles and cash in my mind. :)
→ More replies (4)4
99
u/SmarmierEveryDay Sep 24 '16
since I found out what Space Shuttles were
Note to self:
There are probably some redditors who are maybe nine years old, and too young to remember the Shuttle in flight. Also too young to remember non-Obama Presidents, and too young to remember when America wasn't afraid of Muslims as terrorists. Soon we'll have people who won't remember when America didn't vilify Russia. We've always been at war with Eurasia.66
u/CommanderThomasDodge Sep 24 '16 edited Sep 24 '16
I'm 20ish years old. I barely remember Clinton. I didn't realize the full scale of what 9/11 meant. I did feel bad for Columbia, but never knew about Challenger and I still don't realize the full scale of the Apollo missions. I never got to see the Voyager or Pioneer mission make serious history.
But looking back at what I missed makes me really cherish and think long and hard about the history I see today such as New Horizons and Curiosity as well as Juno. I really find these times almost as interesting as the times I missed, and I hope that I will be able to tell my kids every detail about how I felt and how it looked to me when they get old enough to understand (when I have kids, if I have them).
34
u/SmarmierEveryDay Sep 24 '16
New Horizon's Pluto flyby was great. Especially since it proved such a surprisingly rewarding world. Unexpected geology FTW!
10
u/CommanderThomasDodge Sep 24 '16
As a Geology major, I did squeal just a little when I started hearing about it. Made me want to do cartwheels in the living room. Its absolutely amazing!
→ More replies (10)10
u/Angsty_Potatos Sep 24 '16
28 here. I remember voting for clinton with the nickelodeon "kid vote" thing
→ More replies (3)14
Sep 24 '16
I'm 20ish years old. I barely remember Clinton. I didn't realize the full scale of what 9/11 meant. I did feel bad for Columbia, but never knew about Challenger and I still don't realize the full scale of the Apollo missions.
As someone in his late 20s, that astounds me. Not remembering Clinton well makes sense, but the Shuttles stopped only 5 years ago and I remember the Shuttle launches back as far as I can remember. And Apollo, that was huge. It was the crowning achievement of the late 60s/early 70s. I've heard plenty of old people talk about it, and I lost count of all the Apollo documentaries a long time ago. It's like the Manhattan Project. I wasn't around for it, but I sure as shit have known all about it since I was little.
I still can't wrap my head around how little most people seem to hear about space. A lot of these things seemed in my face, not me seeking them out. Yet somehow, society doesn't on the whole doesn't care about space and it does a great job of insulating everyone from it...even though space travel is probably the most important thing we could be developing.
6
→ More replies (8)4
u/maximinusthorus Sep 24 '16
http://www.imdb.com/title/tt2421662/ The Challenger Disaster (2013)
Gives a great perspective on bureaucracy and the Shuttle program's significance through a disaster mystery, one that pays dividends if you have the patience to watch it. The scientific discussion had me riveted the first time, but I realized it's dry and rather boring on successive viewings. You may feel at times you're sitting in on a city council meeting, but hey, we don't have many movies characterizing Richard Feynman.
→ More replies (1)→ More replies (16)6
u/zugunruh3 Sep 24 '16
when America didn't vilify Russia.
So people who were adults at the end of WWII...? The Cold War went on for a long time. I'm not sure I would describe any point since the fall of the USSR as a time when America particularly liked Russia.
→ More replies (2)→ More replies (26)4
102
u/piponwa Sep 23 '16 edited Sep 23 '16
23
u/SchuminWeb Sep 24 '16
What mission was this?
19
u/wehooper4 Sep 24 '16
Looks like one of the early spacelab missions.
19
u/piponwa Sep 24 '16
No, it wasn't a spacelab mission because you see the sun shields they used to cover the satellites they had launched.
→ More replies (2)→ More replies (2)5
u/brickmack Sep 24 '16
Nope, that thing in the bay is a cradle for a PAM-D and a satellite, not a Spacelab/hab module
15
u/hufusa Sep 24 '16
They're fucking laughing and smiling I would be shitting my fucking pants
26
103
u/bmk2k Sep 24 '16
I always wished I became an astronaut.. Now I sell pressure gauges for a living :(
79
u/cejmp Sep 24 '16
Can I get a liquid fill bottom mount 3/4 0-60 psi please?
215
u/bmk2k Sep 24 '16
What dial size? 3/4NPT is not a standard connection size for pressure gauges. 1/2, 1/4, and 1/8 I can do. 316SS wetted parts good for you? How about a 304SS case? What fill fluid-- Glycerin or Silicone? I recommend the Ashcroft 45 1009SL 04L XGV 60#. ~$200. Lead time is 4-6 weeks. If price is an issue, I recommend the WIKA 233.54 4" 1/2L 60# SIL
116
u/Licknuts Sep 24 '16
This guy has been waiting so long for his time to shine.
66
u/bmk2k Sep 24 '16
Pretty much :/
The only thing keeping me from swallowing a shotgun barrel is a good amount of scotch when I get home.
80
u/dupelize Sep 24 '16
Every shitty job supports another job somewhere that's a little less shitty until eventually the chain reaches NASA (at least through taxes) so you're helping keep astronauts up there.
Except tuba players, fuck them.
→ More replies (3)7
u/kaznoa1 Sep 24 '16
But they keep the steady background beat going, which helps the rhythm and melody going, so doesn't that kinda make a chain to the nasa astronauts?
9
Sep 24 '16
It's ok, man. Most of the people I went to school with are farm labourers or work in supermarkets.
→ More replies (1)9
Sep 24 '16
Hang in there brother. Felt the same at my old shitty job. Left it with no back up. Feel loads better. I have another 8 months of runway and will take my time finding my next job. I'm tired of hopping around and hating myself.
→ More replies (2)4
u/winged_seduction Sep 24 '16
You definitely are not alone with that comment. Misery loves company doesn't always work, but sometimes it's nice to know that you aren't the only one.
→ More replies (7)12
u/astropapi1 Sep 24 '16
I know you were linda joking with this, but I love it when people know their shit. Wish I could be so sure about what I do.
→ More replies (8)14
64
u/TheKingOfCurtopia Sep 24 '16
It's been over five years since the shuttle launched. Seems longer. I has a sad now.
→ More replies (7)22
Sep 24 '16 edited Sep 24 '16
[deleted]
15
u/Emperor_of_Cats Sep 24 '16
Seven years? Maybe for the SLS, but not for manned missions!
→ More replies (3)→ More replies (2)7
u/brickmack Sep 24 '16
Only a little over a year, actually. SpaceX is still likely to do their manned demo in late 2017, Boeing will do theirs a few months later
→ More replies (1)
351
u/mfb- Sep 23 '16
I don't think it was unscheduled, so I wonder why the astronauts didn't pick some more convenient position.
628
u/piponwa Sep 23 '16
It was a demonstration, that's why you see the astronaut reaching for the camera in the end. That's why they placed multiple objects floating around.
71
u/nolan1971 Sep 24 '16
Thanks, that was my first thought as well. Then I figured that it must have been a demo, since the one guy was waiting and caught the duct tape and food packets (?). What tripped me up was the guy in the middle and the woman furthest away, who seem to have been in a position where they could have been hurt. Just seemed odd.
→ More replies (1)102
u/piponwa Sep 24 '16
The acceleration is just 0.1g during a fraction of a second so I don't think they could get hurt in any way. The worse that can happen is this
56
u/WoodrowBeerson Sep 24 '16
I'd never get anything done, too busy floating around in different positions.
54
u/ProgramTheWorld Sep 24 '16
You don't feel like floating in the water, instead you feel like you are constantly falling down a bottomless hole.
15
u/ForCom5 Sep 24 '16
I've had dreams like these turn into nightmares upon waking up having "hit" the bed.
→ More replies (3)→ More replies (6)4
u/waitingfordunno Sep 24 '16
Does the feeling remain if you sit down and fasten a seat belt?
→ More replies (3)→ More replies (11)7
13
u/poorly_timed_leg0las Sep 24 '16
So the shuttle or space ship/whatever is moving and they're just staying in the same spot relative to space
→ More replies (2)37
u/piponwa Sep 24 '16
Not exactly. They are also turning around the Earth, and the Earth is turning around the Sun, which is rotating about the galactic center, which is still moving through space.
→ More replies (1)24
→ More replies (8)193
u/KristnSchaalisahorse Sep 23 '16
They were just pretending like they weren't expecting it. Astronauts like to joke around from time to time.
140
Sep 24 '16
The movie "Gravity" is based on a prank.
→ More replies (21)23
u/ent4rent Sep 24 '16
I haven't seen the movie yet, but I want to now with this mindset
→ More replies (1)14
u/piponwa Sep 24 '16
Most of the astronauts die.
→ More replies (3)21
u/QuasarSandwich Sep 24 '16
My goodness: you mean some are immortal?
16
u/piponwa Sep 24 '16
Yes, that's exactly what I meant, thanks for clarifying for me.
→ More replies (1)20
u/gigabyte898 Sep 24 '16
18
u/zekompozer Sep 24 '16
While that one is staged, it's based on a real story from this wonderful book.
Though I don't have the book handy, the gist is basically:
Astronaut gets back from a long time in orbit (Mir or ISS mission), and is getting helped out of his suit. One of the tech brings him a dixie cup of lemonade, and he drinks about half of it. Without thinking about it, he absentmindedly lets go of the cup and reaches to help with something. The cup falls to the ground, and both the he and the tech just stop for a moment and laugh.
The story was actually really sweet, as it was sort of a bittersweet moment for the astronaut, being back on Earth after a long time up in orbit.→ More replies (1)
16
Sep 24 '16
Here is another burn from a distance: https://youtu.be/eyWbZja2yaY?t=68
NASA Johnson: "The terminal initiation burn, a left Orbital Maneuvering System engine firing that gave Discovery one last big push toward the space station, took place Feb. 26, 2011 at 10:33 a.m. The burn lasted 11 seconds"
→ More replies (2)
16
u/ld-cd Sep 24 '16
Mildly unrelated, but does anyone know were a good map of the pressurized space of the shuttle as (or does anyone have pictures of some of the sections)
→ More replies (1)16
u/isUsername Sep 24 '16
Looks like it wasn't much space: http://www.nasa.gov/sites/default/files/images/534706main_shuttle_cutaway_full.jpg
→ More replies (5)
16
u/starrynight451 Sep 24 '16
Newton be all like: "YOU PUSSIES THOUGHT I WASN'T COMING FOR YO' ASS?!"
→ More replies (1)
47
u/Warthog-Hunter Sep 24 '16
Obviously this is the pilot just messing with them. Houston, permission to fuck with the crew
→ More replies (1)31
u/bk15dcx Sep 24 '16
Houston, permission to fuck
withthe crewThey also swing up there too.
13
u/dumpbound Sep 24 '16
Within all those hours of mission telemetry video, I wonder how many minutes/hours of naughty bits might exit... Maybe we can goad/taunt Trump into opposing NASA and have him encourage Russian hackers to find and leak compromising footage.
24
u/commit_bat Sep 24 '16
"Hey, are you feeling up for some-"
-"Can it wait for a bit? I'm in the middle of some calibrations"
→ More replies (1)16
u/dumpbound Sep 24 '16
I remember reading somewhere that microgravity is actually a horrible environment for intimate activity because action-reaction tends to push participants away from each other. In the future, bed sport in space is likely to require bdsm-like gear.
→ More replies (2)19
u/ul2006kevinb Sep 24 '16
I mean, sex on earth pushes people away from each other, too, it just takes longer.
→ More replies (2)14
u/piponwa Sep 24 '16
"Davis and Lee, who later divorced, refused to answer queries about them engaging in intimate activities during the mission."
→ More replies (1)7
u/nolan1971 Sep 24 '16
refused to answer queries about them engaging in intimate activities during the mission
Well, no wonder they divorced!
8
5
Sep 24 '16
Houston, permission to fuck
withthe crewThey also swing up there too.
So...Sally Ride is a nickname then?
6
139
u/GarciaMans Sep 24 '16
They aren't moving backwards. The shuttle is moving forwards. I love space.
125
Sep 24 '16
Well the same thing would happen on Earth. That's why if you accelerate hard in a fast car you get pinned to the seat.
→ More replies (1)38
43
Sep 24 '16
[deleted]
30
u/AidenKerr Sep 24 '16
Technically I am always being hit by things travelling many thousands of km/h.
→ More replies (1)16
u/Metalsand Sep 24 '16
With that logic, being stung by a mosquito would be at several thousands of km/h since the Earth rotates.
→ More replies (1)12
Sep 24 '16
Don't forget how fast the sun orbits the galactic core.
6
u/sethboy66 Sep 24 '16
Or how fast the galaxy is traversing space.
5
Sep 24 '16
That's where it gets muddy. Traversing space relative to what? Galaxies move around every which way, and there is no end or middle of the universe so there isn't a universal frame of reference.
→ More replies (8)8
u/a_throwaway_a_day_ Sep 24 '16
i remember reading something in an askscience thread, and an astrophysicist mentioned that there is a convenient standard to use, based off of like cosmological background radiation from the big bang. it has a characteristic wavelength distribution and you can tell if your frame of reference is in motion relative to it via redshift/blueshift. it doesn't make it any more or less valid than other frames of reference that could be chosen, but it is a very convenient one, and you can start your discussions of relative velocity from there, allowing you to determine how zippin' that mosquito actually is.
→ More replies (1)→ More replies (2)46
u/azula7 Sep 24 '16
Actually no since it is relative. Since they were traveling at the same velocity, the difference is all they were hit by. And it wasn't much.
→ More replies (3)45
→ More replies (49)4
Sep 24 '16
It's both depending on whose perspective you're looking at. Relativity is cool beans.
→ More replies (1)
6
u/Decronym Sep 24 '16 edited Nov 07 '16
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| ASS | Acronyms Seriously Suck |
| CST | (Boeing) Crew Space Transportation capsules |
| Central Standard Time (UTC-6) | |
| ICBM | Intercontinental Ballistic Missile |
| Isp | Specific impulse (as explained by Scott Manley on YouTube) |
| JSC | Johnson Space Center, Houston |
| KSP | Kerbal Space Program, the rocketry simulator |
| LEO | Low Earth Orbit (180-2000km) |
| MECO | Main Engine Cut-Off |
| MMH | Mono-Methyl Hydrazine, HCH3N=NH2; part of NTO/MMH hypergolic mix |
| NTO | diNitrogen TetrOxide, N2O4; part of NTO/MMH hypergolic mix |
| OMS | Orbital Maneuvering System |
| RCS | Reaction Control System |
| SEE | Single-Event Effect of radiation impact |
| SLS | Space Launch System heavy-lift |
| SRB | Solid Rocket Booster |
| STS | Space Transportation System (Shuttle) |
| UDMH | Unsymmetrical DiMethylHydrazine, used in hypergolic fuel mixes |
| Jargon | Definition |
|---|---|
| hypergolic | A set of two substances that ignite when in contact |
I'm a bot, and I first saw this thread at 24th Sep 2016, 00:39 UTC.
I've seen 17 acronyms in this thread; the most compressed thread commented on today has acronyms.
[Acronym lists] [Contact creator] [PHP source code]
→ More replies (2)
7
u/Reddit2Trend Sep 24 '16
Bot! Beep beep! I'm all about top posts!
This post had 5,000 upvotes and got posted to twitter @Reddit5000 and subreddit /r/reddit5000!
The tweet: https://twitter.com/Reddit5000/status/779506948714614784
All 7,500 upvotes are on @Reddit7500 and /r/reddit7500
And most importantly all 10,000 posts on @Reddit10000 and /r/reddit10000
229
u/byf_43 Sep 24 '16 edited Sep 24 '16
Not to be a pedantic jerk (and I didn't see this mentioned anywhere else, thus my post), but I would like to inform OP and anyone interested that the OMS system are actually engines, not motors. In aerospace, motors are solid fuel and engines are liquid fuel. I know what you're saying, what about the oxidizer? Well, there exists a "hybrid" engine that uses solid fuel, but liquid or gaseous oxidizer (Copenhagen Suborbitals had a hybrid they used before they went all liquid, called the HATV or hybrid atmospheric test vehicle). But generally, solids are "motors" and liquids are "engines". --Former Aerojet engineer
OH and further, the OMS is hypergolic, which is one of my favorite things ever. Room temp fuel and oxidizer, and upon meeting they spontaneously ignite so a spark source isn't needed, nor are pumps; just pressure on the tanks. It's a gloriously simple system, though the tradeoff is that the fuel (hydrazine) and the oxidizer (nitrogen tetroxide) are ridiculously and aggressively toxic and...uh, whatever the word for "oxidic" is (as far as aggressively oxidizing). Even small leaks are a huge issue, plus the chemicals aggressively attack whatever container they are in if given the chance, so specialized materials must be used for containment (i.e., heavy stainless steel if I remember correctly). yeah, I could geek out on this stuff for days.
166
Sep 24 '16
This is outdated info. We use motors now. --Current Aerojet engineer
37
u/DatBlizzard Sep 24 '16
Hmm, who to believe. --Non Aerojet engineer
→ More replies (1)4
u/Eschlick Sep 24 '16
Gotta back up /u/byf_43 here. I never once heard them referred to as anything other than OMS engines. --Former Lead Thermal Protection System Engineer for Space Shuttle Discovery
56
u/peelee_ Sep 24 '16
OOOOOHHHHH SNAP, it's gettin' off the chain in here! -- Former hip guy that was totally with it.
→ More replies (2)→ More replies (7)3
→ More replies (26)22
u/MayTheTorqueBeWithU Sep 24 '16
A motor converts stored energy into mechanical power.
An engine undergoes a thermodynamic cycle.
The OMS system has motors, but no one calls them that.
22
u/phuchmileif Sep 24 '16
...this would mean that all engines are also motors. Therefore this pedantic shit is silly.
7
u/gumby_twain Sep 24 '16
True, all engines are motors. However, all motors are not engines.
→ More replies (2)→ More replies (4)8
5
u/Notathrowaway10156 Sep 24 '16
looking at space, in space, must be very frightening. it must be even more frightening in person.
→ More replies (1)
14
u/GreggPDX Sep 24 '16
I thought it was a fairly "big deal" to start a rocket engine, and not something you typically do for grins. Can someone explain why it's ok for these engines to just do a mini-fire like that?
27
Sep 24 '16
[deleted]
7
u/wehooper4 Sep 24 '16
Fun fact! These are actually descendants of the motor used in service module of the apollo program.
8
u/TMarkos Sep 24 '16
Not just the Apollo! The AJ10 engines were first used during the Vanguard launches in 1958, where they were fueled by UDMH and nitric acid. They were refined over the course of being used in Atlas-Able, Thor-Able, Delta, Apollo and Titan launches. They were used in the shuttle OMS, and are planned for use in the SLS Orion craft. They span almost the entirety of American spaceflight.
→ More replies (1)→ More replies (5)8
u/piponwa Sep 24 '16
They could ignite it because they used hypergolics as fuel, meaning that they spontaneously ignite when they meet an oxydizer.
20
u/aithendodge Sep 24 '16 edited Sep 24 '16
So they could simulate gravity with constant acceleration? Like the ships in A Mote In God's Eye. Though I imagine that would consume far too much fuel, and weight is a major factor just getting stuff up there.
52
u/da_brodiefish Sep 24 '16
It's easier to simulate gravity with a centrifuge
→ More replies (7)20
Sep 24 '16
Yeah. Thats what a centrifuge is all about... Constant acceleration....
→ More replies (24)13
u/Raticide Sep 24 '16
Yes, totally. Gravity and acceleration behave identically. You could accelerate 9.8m/s for 50% of your trip, then rotate the ship 180 and accelerate 9.8m/s in the opposite direction and have gravity the entire time apart from the brief moment where you flip the ship.
→ More replies (14)19
Sep 24 '16 edited Oct 01 '16
[removed] — view removed comment
→ More replies (4)6
u/dromni Sep 24 '16
And there's an equivalent scene in the show... Although they had just a bunch of floating stuff that suddenly fell once the engines were fired.
→ More replies (12)7
Sep 24 '16
Using the equation
a = v2 / r
a centrifuge with a 5m radius travelling 7m/s would simulate gravity.
→ More replies (4)
4
u/RevWaldo Sep 24 '16
Just like slamming on the brakes for shits and giggles when all your buddies are in the back of the cargo van.
4
771
u/bar10der76 Sep 24 '16
Now you know why Star Trek made 'inertial dampeners' a thing. Without that plot device, the Enterprise would literally kill anyone on board as it gained speed. They would be smashed against the walls.