The Space Thread!

TerranCmdr

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Super interesting video about the Soyuz. I totally understood the orbital dynamics - thanks KSP!

Also, the guy in the middle uses a finglonger!
 

GRtak

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Don't know if anyone else has seen this yet, but the Space X rocket made it to it's landing pad,.. and then hit it hard.


 

CraigB

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Well that hasn't gone well.
 

leviathan

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Summary of what has actually happened there for those interested: the test was a huge success, despite the rapid unscheduled disassembly event.

Previous attempts to land the Falcon-9 first stage used cold nitrogen thrusters and engine gimballing to control descent; this allowed to guide it down and arrive at a 0/0 touchdown on water (zero velocity at zero altitude - meaning if it arrived on something solid, it would've been a safe landing). However, the descent accurary was way low to hit a landing pad - it was determined that additional aerodynamic control surfaces are needed to more precisely guide the stage down, especially during hyper- and supersonic descent phases. This was implemented using the grid fins, first test-flown on an F9R testbed, and now used for the first time on an actual Falcon-9 flight.

The grid fins are hydraulically actuated, and use an open hydraulic system that takes RP-1 (rocket fuel) from a gas-pressurized tank at the top of the rocket acting as hydraulic fluid, and discards it into the main fuel tank after use. Such a system is much lighter than traditional closed-cycle hydraulics using a pump and a return circuit, which is sort of essential on a rocket. The downside is, it can run only run for a limited time before running out of pressurized hydraulic fluid... which is exactly what happened about a minute before touchdown on this flight, due to a miscalculation of the amount of fluid needed (apparently, an additional 10% would've sufficed). This left the grid fins unpowered and stuck in a non-neutral position, preventing the rocket from turning to vertical attitude for landing. What happened next is clearly visible in the video: despite having no aerodynamic control, the rocket still managed to arrive at the "drone spaceport ship" (barge), albeit at a 45? tilted attitude. The landing gear broke away due to excessive lateral velocity, the engine block impacted the landing pad, and what little fuel remained at the bottom of the tank exploded, propelling most of the stage overboard.

Results: the barge is pretty much fine, pictures showed it probably lost one of the four diesel generator blocks used for propulsion and some additional on-deck hardware. This is essentially superficial damage and is being repaired in port right now. Next flight is scheduled on January 31st, the Falcon 9 will be launching the DSCOVR spacecraft to the Sun-Earth L1 Lagrangian point, and attempting to recover the first stage again - this time with 50% more hydraulic fluid, so at least it should explode for a different reason (c) Elon Musk.
 

IceBone

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Well, you live and you learn. It's great being present at these stages of development of rocketry, it's almost like during the space race in the 60's, except everything is on youtube. :p

In other news, I've totally been geeking out over Star Citizen again after I got my new graphics card which can actually run it properly and now that I'm no longer constantly thinking how badly the game's running and what I could do to improve performance, I can actually focus on being immersed into it and get some role play on. For the first time in a year, not being annoyed by performance issues, I was literally taken aback at how epic it looks. No need for microgravity or fancy steroscopic 3D, I actually felt like I was in space.

[video=youtube;LVamdir-I7c]https://www.youtube.com/watch?v=LVamdir-I7c[/video]
(give it a bit, it's being processed into 1080p60)


And yeah, if you don't pay attention to where you're going, you crash into an asteroid. :lol:
 

GRtak

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LOOK! The Asteroid That Flew Past Earth Tuesday Has Its Own Moon

In celestial terms, asteroid 2004 BL86 pretty much buzzed the Earth on Tuesday, coming within 745,000 miles of our planet.

As NPR's Sam Sanders explained, Monday's flyby is the closest a known asteroid of this size will pass by Earth in at least the next two centuries.

This means that when the asteroid flew by yesterday, scientists trained their instruments on the body. Scientists using the Deep Space Network antenna at Goldstone, Calif., captured a stunning set of images that revealed 2004 BL86 has a small moon.


NASA's Jet Propulsion Laboratory explains this phenomenon is actually pretty common:



"The 20 individual images used in the movie were generated from data collected at Goldstone on Jan. 26, 2015. They show the primary body is approximately 1,100 feet (325 meters) across and has a small moon approximately 230 feet (70 meters) across. In the near-Earth population, about 16 percent of asteroids that are about 655 feet (200 meters) or larger are a binary (the primary asteroid with a smaller asteroid moon orbiting it) or even triple systems (two moons). The resolution on the radar images is 13 feet (4 meters) per pixel."

gif is at link
 

leviathan

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Awesome animation. Though one small mistake - Elon said in the reddit AMA that while they do have a capability to return the center core to the launch site, the payload penalty for doing so would be significant, and on certain missions it'll be impossible altogether. So they will mostly be using the barge and landing the center core further downrange, without wasting fuel on a boostback.

Update Interesting, I've just noticed the animation is by SpaceX themselves. Maybe this is the preferred mission profile despite the payload penalty.
 
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h-p

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Few videos from Roscosmos:

If the Sun were replaced with other stars:

If the Moon were replaced with planets:
[video=youtube;75Ga-WBa-BE]https://www.youtube.com/watch?v=75Ga-WBa-BE[/video]
 

CraigB

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