SpaceX Tuesday...
Discussion
Flooble said:
Is there such a thing as a rocket throttle on "idle"?
Most space launch first stages are "throttlable" (is that a word?) you may have heard them backing off the power after take off until they have passed maximum dynamic aerodynamic pressure and then "give it the beans" to avoid flying the rocket apart in the thick, lower atmosphere.I presume there is a scale of Off-Fully on for rockets which includes a minimum gas flow required to sustain propulsion but isn't the Full possibly output.
Pure solid rockets are off or on, hybrid rockets with solid fuel and a liquid activator are throttle-able, its like what Bloodhound WLSR car will use.
scubadude said:
Most space launch first stages are "throttlable" (is that a word?) you may have heard them backing off the power after take off until they have passed maximum dynamic aerodynamic pressure and then "give it the beans" to avoid flying the rocket apart in the thick, lower atmosphere.
I presume there is a scale of Off-Fully on for rockets which includes a minimum gas flow required to sustain propulsion but isn't the Full possibly output.
Pure solid rockets are off or on, hybrid rockets with solid fuel and a liquid activator are throttle-able, its like what Bloodhound WLSR car will use.
We have had thottleable (yes, it is the word used) liquid fueled rockets since the mid 1950s. The first practical throttleable rocket engine was the XLR-99 which was designed for use in the X-15 rocket plane. It took a long time to get this engine to work reliably and for the first few years of the X-15 programme, the X-15 was fitted with two sets of lower powered XLR-11 engines - which was NOT throttleable.I presume there is a scale of Off-Fully on for rockets which includes a minimum gas flow required to sustain propulsion but isn't the Full possibly output.
Pure solid rockets are off or on, hybrid rockets with solid fuel and a liquid activator are throttle-able, its like what Bloodhound WLSR car will use.
The RS25 engines on the Shuttle were throttleable but the throttle down and throttle up sequences were controlled automatically by the on board computers. The Shuttle crews were not pushing or pulling on any sort of throttle lever.
The Solid Fuel SRBs were not properly thottleable but the solid fuel was packed and shaped in such a way that the thrust dropped off at the point where the Shuttle main engines throttled back up again. Once past that segment of the climb to space, the solid rocket thrust increased again as the solid propellant shape resumed a shape that allowed greater thrust.
We now have hybrid solid motors which allow an element of thrust adjustment so we are getting to a point where we can say that a solid rocket motor can be throttled.
Eric Mc said:
We have had thottleable (yes, it is the word used) liquid fueled rockets since the mid 1950s. The first practical throttleable rocket engine was the XLR-99 which was designed for use in the X-15 rocket plane. It took a long time to get this engine to work reliably and for the first few years of the X-15 programme, the X-15 was fitted with two sets of lower powered XLR-11 engines - which was NOT throttleable.
The XLR-11 did have a kind of throttle capability - it had four thrust chambers which could be ignited independently, so capable of giving four levels of thrust ( or 8 in the X-15 with two of them fitted )Perhaps you guy could help. Not an expert on Space flight but space x seems to be doing far more far faster than we have before.
Is it that great or new or just standing on the shoulders of ( massive) NASA Giants?
Sure looks impressive to a newb like me.
Mike
Ps did a search but not read entire thread so if already answered, I sincerely apologise,
PPS this all makes space more interesting for me than it has done for years.
Is it that great or new or just standing on the shoulders of ( massive) NASA Giants?
Sure looks impressive to a newb like me.
Mike
Ps did a search but not read entire thread so if already answered, I sincerely apologise,
PPS this all makes space more interesting for me than it has done for years.
SpaceX have a bunch of things going for them.
They are building on well known and understood rocket engineering
3D printing
Modern computing and design
Not being afraid to iterate and develop
Not having excessive government lead profits as its only motivator
Led by a guy who has a vision and drive
They are building on well known and understood rocket engineering
3D printing
Modern computing and design
Not being afraid to iterate and develop
Not having excessive government lead profits as its only motivator
Led by a guy who has a vision and drive
Also understand SpaceX isnt doing anything that traditional aerospace companies couldnt have done a decade or two before.
They though have just been lazy living of the fat of public funds never investing any of their own money in making space travel cheaper, its not in their interest.
They though have just been lazy living of the fat of public funds never investing any of their own money in making space travel cheaper, its not in their interest.
RobDickinson said:
Also understand SpaceX isnt doing anything that traditional aerospace companies couldnt have done a decade or two before.
They though have just been lazy living of the fat of public funds never investing any of their own money in making space travel cheaper, its not in their interest.
This. They though have just been lazy living of the fat of public funds never investing any of their own money in making space travel cheaper, its not in their interest.
Space X have taken the likes of boing and lockheed by surprise and creating a real competitor to the modern 'space race'
Space travel carries huge costs, a lot of which is down to fat cats taking all the cream they can.
So do we buy the musk manned missions and Mars gig?
I was IM a friend from uni who's involved with MIT who said musk was pumping money into some theoretical FTL research. Credible ? He's in AI research so could be coffee shop rumour.
Musk certainly seems willing to throw cash around but FTL sounds boldocks.
Mike
I was IM a friend from uni who's involved with MIT who said musk was pumping money into some theoretical FTL research. Credible ? He's in AI research so could be coffee shop rumour.
Musk certainly seems willing to throw cash around but FTL sounds boldocks.
Mike
MartG said:
Eric Mc said:
We have had thottleable (yes, it is the word used) liquid fueled rockets since the mid 1950s. The first practical throttleable rocket engine was the XLR-99 which was designed for use in the X-15 rocket plane. It took a long time to get this engine to work reliably and for the first few years of the X-15 programme, the X-15 was fitted with two sets of lower powered XLR-11 engines - which was NOT throttleable.
The XLR-11 did have a kind of throttle capability - it had four thrust chambers which could be ignited independently, so capable of giving four levels of thrust ( or 8 in the X-15 with two of them fitted )mikees said:
So do we buy the musk manned missions and Mars gig?
I was IM a friend from uni who's involved with MIT who said musk was pumping money into some theoretical FTL research. Credible ? He's in AI research so could be coffee shop rumour.
Musk certainly seems willing to throw cash around but FTL sounds boldocks.
Mike
SpaceX manned missions are proceeding, NASA have booked a dragon2 mission to ISS with people later this year if the test max q abort goes ahead well in September(?)I was IM a friend from uni who's involved with MIT who said musk was pumping money into some theoretical FTL research. Credible ? He's in AI research so could be coffee shop rumour.
Musk certainly seems willing to throw cash around but FTL sounds boldocks.
Mike
SpaceX are also going ahead with a 2018 'Red Dragon' mission too, thats quite an aggressive timeline and SpaceX havnt always been the best at hitting those..
I think the thing about Musk and therefore Spacex is that they're willing to take financial risks that the existing big players can't because of their boards/shareholders. Spacex has invested heavily in technological developments that have long term payoffs which are now giving them a big competitive advantage.
Thanks rob, good insight. You say SX haven't been good at hitting deadlines. Is this absolute or relative as it seemed from my youth that NASA would slip a decade.
I'm looking at the as an uninformed observer but looking at Tesla, which is prob not a fair comparison, SX seem to be kicking the previous timescales arse.,
I may be wrong so apologies.
It's very exciting tho isn't it!
PS sorry for getting all Boy Scout about this. The whole vertical recently starts to look a bit exciting
I'm looking at the as an uninformed observer but looking at Tesla, which is prob not a fair comparison, SX seem to be kicking the previous timescales arse.,
I may be wrong so apologies.
It's very exciting tho isn't it!
PS sorry for getting all Boy Scout about this. The whole vertical recently starts to look a bit exciting
Old Aerospace like ULA never expected private industry to even exist here.
The whole development was from WWII and ICBMs built around government contracts, none of which talked about reuse or cost, its all pork for them.
Can you imagine the discussion in the boardroom 15-20 years ago?
exec 1 : Lets make our rockets reusable, we'll make them 50% cheaper!
exec 2 : That means 50% less profit, no chance!
Now SpaceX have come into the business, at first they were treated as a joke. Then old aerospace tried to block them out of the market, a whole heap of dirty tricks played in Washington. Then before the behemoths of aerospace could react we suddenly (in time terms a year or two) have re-usable rockets and they have absolutely no clue how to combat this commercially, never had to compete, likely cant.
ULA will continue, because they have to, for now, they get $800 million a year just to exist and be able to launch.
For comparison a Delta IV launch is $300million + and a F9 is about $60 million before any cost savings for reuse. For military those costs go up some, but for the last contract ULA didnt even bid, even after a $800 million sweetener..
There are currently some missions SpaceX cant do with the F9 so thus the F9h which should be able to do everything apart from manned moon/mars missions. Considering the Delta IV heavy flies only every other year its not a big market.
The whole development was from WWII and ICBMs built around government contracts, none of which talked about reuse or cost, its all pork for them.
Can you imagine the discussion in the boardroom 15-20 years ago?
exec 1 : Lets make our rockets reusable, we'll make them 50% cheaper!
exec 2 : That means 50% less profit, no chance!
Now SpaceX have come into the business, at first they were treated as a joke. Then old aerospace tried to block them out of the market, a whole heap of dirty tricks played in Washington. Then before the behemoths of aerospace could react we suddenly (in time terms a year or two) have re-usable rockets and they have absolutely no clue how to combat this commercially, never had to compete, likely cant.
ULA will continue, because they have to, for now, they get $800 million a year just to exist and be able to launch.
For comparison a Delta IV launch is $300million + and a F9 is about $60 million before any cost savings for reuse. For military those costs go up some, but for the last contract ULA didnt even bid, even after a $800 million sweetener..
There are currently some missions SpaceX cant do with the F9 so thus the F9h which should be able to do everything apart from manned moon/mars missions. Considering the Delta IV heavy flies only every other year its not a big market.
mikees said:
Thanks rob, good insight. You say SX haven't been good at hitting deadlines. Is this absolute or relative as it seemed from my youth that NASA would slip a decade.
I'm looking at the as an uninformed observer but looking at Tesla, which is prob not a fair comparison, SX seem to be kicking the previous timescales arse.
SpaceX (and tesla to be fair) have missed every date they have ever set for stuff I think. Its an industry joke. They will do what they say but somewhat later..I'm looking at the as an uninformed observer but looking at Tesla, which is prob not a fair comparison, SX seem to be kicking the previous timescales arse.
So far thats not hurt SpaceX too much , they have (AFIK) lost 1 launch due to missed deadlines but most customers are happy to wait for their launch date because its cheap.
The lost mission last year put them back a fair bit too, they have though already launched as many rockets this year as last, and are aiming for one every 2 weeks by EOY.
Their order book is full for years.
Also consider when they do start to bring the price down this will open up new markets for cheap launches. This will likely be a busy space in a few years as there are several low weight ( < 500kgs) LEO launch private companies coming to the market soon
As for FTL, hmm not heard Musk investing in it but a few million/tens of million that way wouldnt exactly surprise me, or be noticed by Musk.
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