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00:40

NASASpaceFlight.com: Soyuz 2-1B launches latest GLONASS-M spacecraft

posted on February 07, 2016 by Chris Bergin

A Russian Soyuz 2-1B has launched a GLONASS-M Global Navigation satellite from the Plesetsk Cosmodrome. Launch occurred from Pad 43/4 at the spaceport, with T-0 reported as 00:21... No related posts.

16 hours later…

Space Exploration Meta

16:27

Q: What are the major results of ISS experiments?

For about 15 years the astronauts are doing scientific research in the ISS for future space population and traveling.The wide variety of research fields include astrobiology, astronomy, human research including space medicine and life sciences, physical sciences, materials science, space weather,...

1 hour later…

TildalWave

17:35

@kimholder This is a must see workshop for your Moonwards kiss.caltech.edu/new_website/workshops/3d.html (expand the Presentations section, it has both videos and PDFs)

2 hours later…

TildalWave

19:47

@Hohmannfan quasi-inertial attitude mode I believe ntrs.nasa.gov/search.jsp?R=19730032401 probably with fallback to solar inertial attitude hold... Skylab Apollo Telescope Mount had independent targeting capability ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19950003609.pdf

Sadly HORIZONS doesn't have vectors for it

Hohmannfan

@TildalWave "quasi-inertial" hehe. Fixed relative to the Sun is not quite the same as fixed relative to the stars. Does that really matter a lot? :P

TildalWave

@Hohmannfan you're not entirely clear what you mean with "fixed"

(in your question)

Hohmannfan

I know I am not.

Trying to fix that now

TildalWave

well turns out you can have an attitude that is good enough for both solar angle and observations ... considering it did a lot of heliophysics it's actually one and the same anyway

but I think it would be worth also mentioning that the telescope had independent targeting and attitude (3-axis stabilization in this case) capability

that's good for many possible orientations and attitude modes, but also so the guys in the Skylab can goof around and vibrations won't translate to the telescope

Hohmannfan

The difference between those two rotation periods is, BIG SURPRISE! one rotation a year, so it may be easy to switch between them for different types of observations. But is an Earth facing orientation ruled completely out?

TildalWave

20:03

no, probably not but it would be less economical

Hohmannfan

I do not mean switching to that mode, I mean, are we sure Skylab did not have an Earth facing rotation?

TildalWave

I'm not 100% sure, just maybe 80%

Hohmannfan

Kind of like what I thought. I believe it did not, but I was not completely sure

TildalWave

it makes sense since it would have to switch between attitude modes during docking... and that gets a lot cheaper if it's already close to (quasi) inertial

and there would be a lot less of propellant (and thrusters) use

which is also important when you don't have a huge gyro and you're running a microgravity lab

Hohmannfan

"Please leave any gravity outside before entering the microgravity lab."

TildalWave

20:09

well, it's "microgravity" not "zero gravity", so small, personal use doses of gravity should be fine

Undo

20:34

@TildalWave :(

Hohmannfan

20:56

How George E. Mueller decided the Skylab station should look like. Note the artistic skills.

My Other Head

21:19

@TildalWave, If a broad question can be answered, despite being possibly outside question guidelines, should it still be closed?

TildalWave

21:45

@MyOtherHead depends, but list questions or opinion based questions should be closed, and that one you likely inquire about is both

opinion based or unclear, which are synonymous in my book anyway

as in, not clearly defined

there's been some talk of "good subjective vs bad subjective" on SE, but that's just a lot of verbal diarrhea with no clear guidelines

(i.e. I'd suggest avoiding reading it, but it's your time to waste :P)

My Other Head

understand. That's why I gave the OP a broad answer so that they have to wade through mountains of technical papers to find their answer, as penance for asking such a question

TildalWave

I guess it can be understood as a bit cynical, maybe even condescending, but I upvoted it

your answer

downvoted the question

My Other Head

it'll most probably be closed soon anyway.

TildalWave

should be

otherwise I can ask one single question and every new one after that will be a dupe of it

at which point we can just close the shop

My Other Head

and read books and technical papers to answer our questions on our own, while whistling Dixie

TildalWave

21:52

I'm doing that anyway, I doubt I ever asked a question here that was imperative I get an answer to and I couldn't on my own faster

Hohmannfan

<x> closed as duplicate of "How do things in space work?"

My Other Head

Someone actually asked that!!!

TildalWave

@Hohmannfan "What is space exploration?"

(good answers should be as complete as possible LOL)

Hohmannfan

@TildalWave (and include relevant information from related fields) :)

TildalWave

and then annoy whoever answered in comments as soon as something changes, and request updates LOL

Hohmannfan

21:56

How do I write a smiling face at the end of a parenthesis anyway?

The IAU ban came after the 'redefinition of 'planet' to include the IAU president's mom' incident.

(not good :).......(definitely not good:)).......(my own weird solution) :)

TildalWave

(: bad <-> good :)

Hohmannfan

maybe escape it? :)

LOL, it literary escaped it

:\) (written by double \)

(must write three of them to get\\)

TildalWave

use `

Hohmannfan

Elder backslash! \\\\\\

TildalWave

Q: Why have space stations become less efficient despite technological progression?

If you compare the pressurized volume of all the space stations launched to their mass, their mass efficiency seem to decrease over time. In chronological order: Salyut: (actually seven stations, but practically identical. Salyut 1 numbers are used) Pressurized volume: 99 m³ Mass 18,425 k...

crewed-spaceflight design technology space-station mass

@Hohmannfan You're making a bit big assumptions about the meaning of efficiency here

Hohmannfan

22:08

I know, I state mass efficiency as pressurized volume divided by mass later in the question, but I stuck to just "efficiency" in the title :)

TildalWave

even mass efficiency has typically different meanings in spaceflight

Hohmannfan

Should I make it less of a click bait?

TildalWave

you're talking about pressurized volume vs mass

it's not even functional volume

e.g. on ISS a lot of functional volume is unpressurized

I bet that if you used displacement volume instead of pressurized volume, you'd get inverse results

Hohmannfan

But cosmonauts can not jump around and to cool things in unpressurised volume...

TildalWave

@Hohmannfan meh, if that's your intention then I guess it works

it certainly got me going LOL

@Hohmannfan sure, but that doesn't define efficiency

might as well be the opposite as soon as you add words like automation to it

Hohmannfan

22:12

"Why have space stations become less cool despite technological progression?"

TildalWave

e.g., look at all the access space of the robotic manipulators on the ISS

that's a lot of workplace volume

Hohmannfan

I think what is going on is: Translation to modular stations means adding more stuff to it without increasing the pressurized volume.

TildalWave

anyway, I think the use of "efficiency" in your title is a bit misleading

@Hohmannfan no, it's not that ... you're not using the barebone mass of the station

Hohmannfan

TildalWave

First of all, space station's mass is ~ 390,000 kg isslive.com/displays/adcoDisplay1.html, that Wiki quote has always been misleading and includes one Space Shuttle orbiter docked to it

second, a lot of ISS mass are external payloads

Hohmannfan

22:18

remove big plane in space then...

duzzy

Replace it with a space helicopter.

Hohmannfan

ISS mass updated to 390,378 kg. Sadly no helicopter added :(

@duzzy 395,197 kg with Black Hawk helicopter attached.

duzzy

TildalWave

22:35

You see those central cylindrical modules? Those are pressurized volume.

Mass of the station is all of it

Hohmannfan

Yes, therefore the talk of "modular space stations". You are right. And Tiangong is explained by its small size (square-cube law)

TildalWave

The answer to your question is basically in self-sufficiency and utility

if the station depended on consumables only, it could be a lot lighter, but you'd then have to deliver consumables to it

Hohmannfan

But you must admit that less volume for bouncing around is not so cool. That Skylab workshop was amazing!

TildalWave

it would be interesting to see if all that mass was worth it in all this time, basically if it amortized itself in all this time

say, if it used fuel cells instead of solar power, it didn't recycle,... would it consume more mass for the total metabolic rate and power consumption than it needs to be more self-sufficient

Hohmannfan

kind of like the decision of using only batteries and fuel cells for the Apollo

Or the possibility of just packing some snacks instead of a full blown hydroponics module.

(more tasty too)