Elon Musk posted an article "BACKGROUND ON TONIGHT'S LAUNCH" on SpaceX's website 15 minutes before the launch.
Link : http://www.spacex.com/news/2015/12/21/background-tonights-la...
SpaceX launch webcast: Orbcomm-2 Mission [video]
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Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#202Earlier quoted context omitted.
NARS but probably comparable to shuttle engines and body.
The shuttle's main engines were extremely high-performance. They were marvels of engineering but required a lot of work between flights. Just like cars can be optimized for performance or reliability (think Honda Civic versus Ferrari) rocket engines can be made more maintainable and tolerant to long use periods. Not saying Spacex engines are Hondas, but they are probably way less trouble than SSMEs.
Soyez has been flying nearly 50 years. It's the dump truck of space, with 1700 launches to date. Compare that to the much more elaborate Shuttle's 135. Elon would rather have the dump truck than the Ferrari.
Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#203Earlier quoted context omitted.
Can someone explain exactly what Bezos/Blue Origin did, and how it is different than what SpaceX did? EDIT: Here's a video that compares/contrasts: https://www.youtube.com/watch?v=b8c7RUjNFDo
This video ain't bad, but it skims over the two most important points and skips one completely: - SpaceX rocket goes really fast horizontally; it has to flip around and boost back, and then correct from horizontal to vertical orientation. - Falcon 9 is an actual space launch system; it has different (i.e. much stricter) engineering constraints than a suborbital rocket. In particular, this affects the engine design. -…
Why don't they put a smaller engine in the centre for landings?
Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#204This is so exciting. Not quite a moon landing, but still feels like watching a significant moment in history. Does anyone know what specifically changed to allow a landing attempt on land as opposed to barge? Was it just that they gained enough confidence with the barges that they would at least be able to hit the target (and not crash into a building or something), or was some regulatory clearance received or someth…
You guessed right with the lighter payload. They could afford the fuel to burn all the way back rather than landing downrange on the barge.
Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#205What changed that made this cost-effective?
1) The companies pursuing this, SpaceX, Blue Orgin, etc., can't be the first to think of it. If the first stage accounts for 75% of the cost of a launch, as one article I read says, I'm sure many have considered, going back to the first launches decades ago, how to reuse it.
2) The technology to land rockets vertically has existed for a long time, going back to the lunar lander at least.
Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#206Not sure if the "USA" chant after the first stage landed was warranted.
I think the thing to consider is why a private company chose to include this in what looks like a carefully planned marketing presentation.
It's a commercial. What are they selling?
Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#207Earlier quoted context omitted.
The Shuttle engines operate on hydrogen which burns very cleanly. RP-1 will leave the engine dirty with coking, so they definitely need to clean re-assemble each engine. On the other hand, the solid boosters of the Space Shuttle were severely damaged by the impact and corrosion of the sea water, after "recovery" they were essentially a source of parts for new boosters. Overall, I really hope they can improve re-usabi…
The hydrogen in the Space Shuttle Main Engine creates embrittlement in the alloys of the engine. [1][2] The launch sequence also involved running the engines at 104.5% of rated capacity. [3] Before Block II of the engines, the turbopumps needed to be disassembled and rebuilt between flights. [4] I have no real idea how significant coking of the Merlin engine is, but the SSMEs were hardly "clean". [1] https://en.wikip…
IIRC the 104% was additional performance they enabled through upgrades and design improvements beyond the original design not over-driving them.
Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#208I think it's really impressive how SpaceX continues to iterate on the engine and rocket designs. This is the third major revision of the Falcon 9 engine since 2010, each time increasing the thrust and payload to orbit significantly even while operating a commercial launch service. I feel that this kind of willingness to continuously improve and push the envelope is what really sets SpaceX apart from the incumbents. Speed of iteration beats quality of iteration and all that.
It's quite interesting that their biggest competitor ULA is having to rely on tiny Blue Origin to develop a replacement for the Russian RD-180 that ULA uses on their big money maker Atlas V.
Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#209What changed that made this cost-effective? 1) The companies pursuing this, SpaceX, Blue Orgin, etc., can't be the first to think of it. If the first stage accounts for 75% of the cost of a launch, as one article I read says, I'm sure many have considered, going back to the first launches decades ago, how to reuse it. 2) The technology to land rockets vertically has existed for a long time, going back to the lunar la…
"New-space" aerospace companies are operating on a different funding framework from the old aerospace juggernauts. Instead of cost-plus funding that came almost solely from the government and which allowed rockets like ULA's Delta IV and Atlas V to stay competitive in the $300-400 million range without having to find ways to cut costs. SpaceX, Blue Origin, and Orbital Sciences, as well as other new companies, have to innovate in order to make their businesses feasible.
Additionally, Blue Origin and SpaceX have different goals from traditional aerospace firms that requires them to drive costs down below what a government would require. Blue Origin want to offer rides to space to tourists; for that, their costs need to be low enough for a person to buy a ticket. SpaceX wants to land their rockets on Mars, and then take off again. Being able to land the first stage of the Falcon 9 allows them to perfect the landing and reuse of rockets on Earth, before taking that knowledge to Mars.
Re: SpaceX launch webcast: Orbcomm-2 Mission [video]
#210Earlier quoted context omitted.
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I'm not implying that they were holding back on purpose, but I did not expect the quality of the whole streaming event to go up so highly. It feels different than before.
It does definitely... though they really drop the ball after the main event is over at least from a perspective of the news. the news would beat this to death and then after 3 days stop covering it. This was maybe 5 min after the mission was a success that they cut the feed. milk it for all it's worth and show some of the other successes and failures from past missions. It definitely feels like the mission pr was handled by engineers. (not trying to be a jerk as I am an engineer)
Really such a groundbreaking thing like this should be glorified in the media and put on loop for a while. simply amazing.