Doh, where is the/. edit or delete function? Anyway, yes I meant, "Lightsquared". And I realize that this is sort of an ad hominem attack which is not what I really meant either, but my basic question remains.
Does it appear to anyone else that at least half the Lightspeed defenders must be paid shills for the company? Think about it -- GPS has been around for 20+ years and is considered a utility now, the facts of Lightspeed's purchase of the spectrum (only intended for satellite use) are not in question, and neither is the physics of humongously strong signals next to a band where the signals are below the noise floor. And, who gets all excited about some company's spectrum license unless have a vested interest -- it's not usually of much general interest. I'd like to be proved wrong so I can continue to trust he integrity of sites like/. but I'd say , "Reader beware".
If they "drive on the roads", they are paying the state and federal gas taxes to keep the roads maintained. If they "enjoy national parks" they are paying the park entrance fees. "TV programming" -- what? -- unless they are watching PBS they are watching the commercials which pay for that. If by "defended", you mean that Lockheed Martin and Boeing get to rake in $$billions for products which usually don't meet the original specs, then I 'm not sure what service they are getting there.
Considering that half of those "46%" are probably retirees on Social Security and Medicare who have joined the Tea Party to complain about big government spending, I doubt that hitting them with a 1% tax would have changed their vote from whatever nutter promised to keep the government from "pulling the plug on Grandma".
Not exactly hydrazine, but a leak of a similar propellant (nitrogen tetroxide) from the reaction control system on the Apollo spacecraft almost killed the Apollo crew on re-entry during the Apollo-Soyuz mission so there is a reason NASA would look for non-toxic fuels other than just "greenness". From wikipedia, "The only serious problem was due to an Apollo crew mistake during re-entry preparations that resulted in a very rough landing and the entry of noxious gas into the spacecraft. The reaction control system was inadvertently left on during descent, and highly toxic nitrogen tetroxide was sucked into the spacecraft as it drew in outside air."
If you would read the article, some of the reasons are: "also reduce propulsion systems complexity, create fewer operational hazards, decrease launch processing times and increase performance." I would say those are desirable goals in a rocket fuel no matter how knee-jerk crazed a person may be to reject improvements to processes which might make the air we all breathe a bit more pleasant.
I agree with you more than I let on in my first reply, and agree totally with you about the value of the ISS and Shuttle. I just don't think MSL and Webb should get a pass on their overruns -- either you come up with an honest, realistic cost for a mission in your proposal or you don't, we've been doing this long enough to budget better than that. Claims of "new technology" don't cut it because if you know you are going into "new technology" then double (or triple) your planned development budget. But, again, overall I agree with you that the robotic missions have been far better deals for the taxpayers than the crewed missions (since 1975).
It's well known in the community that MSL blew a huge budget on the way to being launched. From 'Space News', 28 January 2011, : "MSL’s price tag has grown by more than $660 million since 2008, according to a February 2010 audit by the U.S. Government Accountability Office, which attributed much of the increase to a 68 percent rise in hardware development costs since the program’s 2003 inception. Although NASA had planned to launch MSL in 2009, technical setbacks forced the agency to postpone the mission two years, the minimal delay for any Mars-bound craft missing its launch window. "
Re:Something not mentioned -
on
Lake Vostok Reached
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· Score: 4, Interesting
On the other hand, the rate of change of some systems is significantly slower than for many other systems. The obvious example is comparing the surface of the moon to the surface of the earth -- the earth had at least the same cratering events as the moon but the moon still displays a surface similar to what it was 2 billion or more years ago. Yes the surface of the moon is the present day surface but unlike the earth it is little changed and so is a good replica of the moon in the past. Geologically the same goes for those asteroids, Mars, etc. and biologically for Lake Vostok and many other isolated biological environments -- there is less competition and influx of new "innovations" from the larger outside world on the organisms there so the biologists say that the living things there have changed less than those in more open environments. The present is not the past but some places in the present are a lot like the past, indistinguishably so.
A quick check on Wikipedia shows that 2,4,5-T made up about 50% of Agent Orange (the other 50% was another herbicide), and 2,4,5-T is considered the more hazardous of the two, so in this case the reference as a component of Agent Orange seems quite legitimate and so is linking the emotional connotations of Agent Orange to the compound in question.
To someone who used to be in military aviation, this is kind of a non-story. It is a rare and undesirable incident but hardly unheard of, except that tool control is very good in military aviation now. You have the mechanics, then you have the Quality Control checkers, then eventually you have the aircrew doing their pre-flight inspection. Most of the time mistakes get caught along the way, very occasionally they don't. Luckily in this case no one got hurt and hopefully the contractor reimburses the government for some of the loss (not $244 million, as other posters have pointed out). It is human error, same as what causes most aircraft accidents in the air and on the ground. When you work with $244 million equipment which flies through the air you will suffer losses sometimes. It's like owning a $100,000 car -- if you drive it on the street you are taking the chance of wrecking it. And $244 M doesn't sound like all that much -- about the same as a new Boeing 777 according to the Boeing price list (http://www.boeing.com/commercial/prices/).
I agree with you 100% but Slashdot is at its worst (and that is saying a lot) when it devolves into a USA Republican vs Democrat debate except in the very rare occasions where there is a clear policy difference between the two which concerns a technical subject (maybe climate change, too). I'd suggest to ignore the partisan trolls and maybe they will go away and infest some other sites.
So much has changed since the '50s you can't make the comparison. Among them -- career opportunities for women (teaching was wide open to them then and not much else), the job outlook for a high school dropout was still pretty good then, college educations were rare, family units across all economic classes were more stable, etc. Society has changed, some things have gotten relatively cheaper (manufacturing), some things have gotten relatively more expensive. Not to say education in the US hasn't somewhere gone off the tracks lately, but we may have to throw money at it to make up for the societal challenges. Look at what healthcare spending has done since the 50's for a parallel example.
You are a brave person to be seeking out '76-'77. In my (amateur but significant) experience '74 through '84 were the worst cars from '55 up. Engines were loaded down with first generation emissions controls, bodies were bloated, heavy and rust prone, suspensions were unsophisticated and barely able to keep those behemoths on the road. Ever rebuilt a carburetor from '76? I found the early fuel injected, computer cars ('85-'97 or so) to be far superior vehicles and easier to work on. Mid-60's cars I liked but are getting really old and hard to find. I'm rebuilding a '96 Turbo Volvo now and finding it a pleasant experience. After about year 2000 I can't handle all the electronics, so the cars have become disposable, but they do last a long time -- lots of good +100k mile examples on the road, you didn't see that in the 60's or 70's.
I read a book about 15 years ago (I think called "Chemical Evolution") which stated that the chirality of living organisms was determined during the "replicating molecule" stage in life's origins because some important chiral molecules are very, very slightly more stable in one enantiomer due to the asymmetry of the nuclear weak force. The math seemed convincing at the time, but I never checked the other references. Sorry I can't give more detail. Is this something which was dismissed by the biology community a long time ago?
Kepler detects planets by seeing periodic small drops in the brightness of the host star as the planet passes in front of it. That is only going to work for planets with a pretty short orbital period (I don't know the limit) since they depend on multiple observations to get the orbital characteristics. Neptune with is 100+ year period would not be measurable and unlikely to be observed even once during the mission.
The discussion here has the electron donors turned around. The "oxidant" such as oxygen takes the electrons from the reducing agent. Oxygen has 6 electrons in its outer shell and needs only 2 more to have a completely full outer shell, thus it has a strong attraction for those 2 more electrons and takes them from less electropositive elements such as metals. You sound like you know what you are talking about so this is probably just to point out a typo, but I post it to prevent confusion on the thread... I realize that covalent bonding such as in CO2 is a bit more complicated, but O is still considered the oxidizer there.
It appears you've never been in a real war. Neither have I but I've seen the pictures from WW I and WW II and read the statistics. You can academically say, "Well they were an inevitable event in the adaptation of 19th century nation-states societies to the 20th century Industrial Age", but that doesn't mean you want your kids to go through that sort of thing -- and I mean the devastation of WW II in Europe and Asia, not the relatively light touch the US got. I'll take a multi-hundred year climate change to which we can adapt over a ten year series of conflicts later called WW III.
Interestingly the 'start-stop' cycle you describe provides a thermodynamic advantage to the four stroke reciprocating engine over a turbine. Because the piston and valves get to be cooled off during the intake stroke they can tolerate higher combustion temperatures during the power stroke. Higher combustion temperature = higher thermodynamic efficiency. In a turbine the blades in the power section are continuously exposed to the hot gases of the combustion section which limits the maximum temperature the combustion can run at. Now there are a lot of other factors -- since the turbine has a separate compressor section from the power section, each can be optimized for its purpose, while a piston has to be a compromise, for example. Anyway, the whole issue of relative efficiencies between the different heat engines is a fascinating subject. I think everyone can agree that no one 50 years ago would have dreamed that piston engines could become as clean and efficient as they are now. As arcsimm points out in the earlier post no one has been able to improve on the reciprocating piston for the small, mobile installations of automobiles, not for lack of trying.
I'm not an expert either but these objects are loosely "captured" by the Earth due to interactions mostly with the Sun I think. Even without the Moon this can happen. If the Earth were totally isolated then this couldn't happen via Newtonian mechanics but the presence of the Sun makes the whole system a three body problem with chaotic effects such as temporary captures. The definition of "temporary" depends on your timeframe -- not much in the Solar System is eternally stable due to multi-body gravitational effects anyway.
Reasonable answer -- I was a bit harsh in my original reply but still pretty much disagree. Two points -- philosophically I like some sort of intake charge compression (turbo or supercharging) because of a basic imbalance in the way a reciprocating engine works -- you have hundreds of psi of exhaust pressure (pushed by the piston) to empty the cylinder but only atmospheric pressure (15 psi) minus throttle losses to fill it on each stroke -- that's why intake valves are always bigger than exhaust valves. Also with a turbo you are able to capture some of the waste heat in the exhaust stream increasing the basic thermodynamic efficiency of the engine. On the whole environmentalism issue -- you have to admit that the engines of 2012 are more powerful and drivable than the best engines of the glory days of the 60's, while being almost infinitely cleaner and considerably more efficient. Of course this is all technology driven but a bunch of that technology was forced by environmental requirements. Since about 1992 (when the new Chevy 5.7 liter LT-1 came out) the car makers have shown we can have it all -- clean, efficient engines and more power than than you can use on the street. This drive to even smaller displacements is just along the same trend as technology gets even better.
Nothing to be too sorry about -- a new 2012 Mustang with a 305hp V6 lists for $22,310 and is EPA rated at 31 mpg for highway fuel economy -- actually quite affordable, not that any compensation is necessary.
The guys that really know cars don't agree with you. When Motor Trend tested the 2011 Ford F-150 Pickups "the idea was to see whether it makes more sense for buyers to get the twin-turbo V-6 or the 5.0-liter V-8" (their quote). Continuing they said, "From the dyno and track results, the EcoBoost's performance data makes it a better rival for the 6.2 (liter V-8). The EcoBoost F-150 was fastest of the test..." The story is at http://www.motortrend.com/roadtests/trucks/1110_2011_ford_f_150_full_line_test/viewall.html. I've owned a variety of big block and factory turbocharged cars including the real good ones -- 427 'Vette, 6.6 Liter Trans Am, 455 Stage 1 Buick, 3.8 liter Buick Turbo-Regal, GMC Syclone 4.3 liter turbo V-6, Volvo 2.3 liter turbo I-5. The turbo cars were better all around performers than the big blocks -- just as fast and better in every other category. One reason is that with a small, lightweight engine the car can be lighter and better balanced. In a direct comparison, I had a hot-rodder friend who owned the following two cars -- '69 Camaro with a transplanted 427 (L88 427 -- the real factory race engine in the late 60's, 7 liters for the metric oriented reader) and an '86 Buick Regal T-Type with the turbocharged 3.8 liter V6. After some garage tweaks the Regal ran a faster 1/4 mile at the dragstrip than the Camaro, both in the 11's as I recall. And I remember guys breaking rods racing naturally aspirated V-8 cars all the time.
I'm going to have to pile on to you for the "fly-by-wire" comment. With personal experience in both types, I can tell you, fly-by-wire airplanes will do things which the old fashioned ones won't. For example, the F-16 is aerodynamically unstable -- a pilot without the help of the computers can't fly it. This built-in instability combined with the flight control computers gives the aircraft the ability to outmaneuver the old ones.
As I badly posted in a previous comment it was a direct derivative of the V2 which launched the first American satellite in 1958. V2 -> Redstone IRBM -> Jupiter C launch vehicle, all developed by Werner von Braun's engineering team.
Slashdot Mirror
Doh, where is the /. edit or delete function? Anyway, yes I meant, "Lightsquared". And I realize that this is sort of an ad hominem attack which is not what I really meant either, but my basic question remains.
Does it appear to anyone else that at least half the Lightspeed defenders must be paid shills for the company? Think about it -- GPS has been around for 20+ years and is considered a utility now, the facts of Lightspeed's purchase of the spectrum (only intended for satellite use) are not in question, and neither is the physics of humongously strong signals next to a band where the signals are below the noise floor. And, who gets all excited about some company's spectrum license unless have a vested interest -- it's not usually of much general interest. I'd like to be proved wrong so I can continue to trust he integrity of sites like /. but I'd say , "Reader beware".
If they "drive on the roads", they are paying the state and federal gas taxes to keep the roads maintained. If they "enjoy national parks" they are paying the park entrance fees. "TV programming" -- what? -- unless they are watching PBS they are watching the commercials which pay for that. If by "defended", you mean that Lockheed Martin and Boeing get to rake in $$billions for products which usually don't meet the original specs, then I 'm not sure what service they are getting there.
Considering that half of those "46%" are probably retirees on Social Security and Medicare who have joined the Tea Party to complain about big government spending, I doubt that hitting them with a 1% tax would have changed their vote from whatever nutter promised to keep the government from "pulling the plug on Grandma".
Not exactly hydrazine, but a leak of a similar propellant (nitrogen tetroxide) from the reaction control system on the Apollo spacecraft almost killed the Apollo crew on re-entry during the Apollo-Soyuz mission so there is a reason NASA would look for non-toxic fuels other than just "greenness".
From wikipedia, "The only serious problem was due to an Apollo crew mistake during re-entry preparations that resulted in a very rough landing and the entry of noxious gas into the spacecraft. The reaction control system was inadvertently left on during descent, and highly toxic nitrogen tetroxide was sucked into the spacecraft as it drew in outside air."
If you would read the article, some of the reasons are: "also reduce propulsion systems complexity, create fewer operational hazards, decrease launch processing times and increase performance." I would say those are desirable goals in a rocket fuel no matter how knee-jerk crazed a person may be to reject improvements to processes which might make the air we all breathe a bit more pleasant.
I agree with you more than I let on in my first reply, and agree totally with you about the value of the ISS and Shuttle. I just don't think MSL and Webb should get a pass on their overruns -- either you come up with an honest, realistic cost for a mission in your proposal or you don't, we've been doing this long enough to budget better than that. Claims of "new technology" don't cut it because if you know you are going into "new technology" then double (or triple) your planned development budget. But, again, overall I agree with you that the robotic missions have been far better deals for the taxpayers than the crewed missions (since 1975).
It's well known in the community that MSL blew a huge budget on the way to being launched. From 'Space News', 28 January 2011, : "MSL’s price tag has grown by more than $660 million since 2008, according to a February 2010 audit by the U.S. Government Accountability Office, which attributed much of the increase to a 68 percent rise in hardware development costs since the program’s 2003 inception. Although NASA had planned to launch MSL in 2009, technical setbacks forced the agency to postpone the mission two years, the minimal delay for any Mars-bound craft missing its launch window. "
On the other hand, the rate of change of some systems is significantly slower than for many other systems. The obvious example is comparing the surface of the moon to the surface of the earth -- the earth had at least the same cratering events as the moon but the moon still displays a surface similar to what it was 2 billion or more years ago. Yes the surface of the moon is the present day surface but unlike the earth it is little changed and so is a good replica of the moon in the past. Geologically the same goes for those asteroids, Mars, etc. and biologically for Lake Vostok and many other isolated biological environments -- there is less competition and influx of new "innovations" from the larger outside world on the organisms there so the biologists say that the living things there have changed less than those in more open environments. The present is not the past but some places in the present are a lot like the past, indistinguishably so.
A quick check on Wikipedia shows that 2,4,5-T made up about 50% of Agent Orange (the other 50% was another herbicide), and 2,4,5-T is considered the more hazardous of the two, so in this case the reference as a component of Agent Orange seems quite legitimate and so is linking the emotional connotations of Agent Orange to the compound in question.
To someone who used to be in military aviation, this is kind of a non-story. It is a rare and undesirable incident but hardly unheard of, except that tool control is very good in military aviation now. You have the mechanics, then you have the Quality Control checkers, then eventually you have the aircrew doing their pre-flight inspection. Most of the time mistakes get caught along the way, very occasionally they don't. Luckily in this case no one got hurt and hopefully the contractor reimburses the government for some of the loss (not $244 million, as other posters have pointed out). It is human error, same as what causes most aircraft accidents in the air and on the ground. When you work with $244 million equipment which flies through the air you will suffer losses sometimes. It's like owning a $100,000 car -- if you drive it on the street you are taking the chance of wrecking it. And $244 M doesn't sound like all that much -- about the same as a new Boeing 777 according to the Boeing price list (http://www.boeing.com/commercial/prices/).
I agree with you 100% but Slashdot is at its worst (and that is saying a lot) when it devolves into a USA Republican vs Democrat debate except in the very rare occasions where there is a clear policy difference between the two which concerns a technical subject (maybe climate change, too). I'd suggest to ignore the partisan trolls and maybe they will go away and infest some other sites.
So much has changed since the '50s you can't make the comparison. Among them -- career opportunities for women (teaching was wide open to them then and not much else), the job outlook for a high school dropout was still pretty good then, college educations were rare, family units across all economic classes were more stable, etc. Society has changed, some things have gotten relatively cheaper (manufacturing), some things have gotten relatively more expensive. Not to say education in the US hasn't somewhere gone off the tracks lately, but we may have to throw money at it to make up for the societal challenges. Look at what healthcare spending has done since the 50's for a parallel example.
You are a brave person to be seeking out '76-'77. In my (amateur but significant) experience '74 through '84 were the worst cars from '55 up. Engines were loaded down with first generation emissions controls, bodies were bloated, heavy and rust prone, suspensions were unsophisticated and barely able to keep those behemoths on the road. Ever rebuilt a carburetor from '76? I found the early fuel injected, computer cars ('85-'97 or so) to be far superior vehicles and easier to work on. Mid-60's cars I liked but are getting really old and hard to find. I'm rebuilding a '96 Turbo Volvo now and finding it a pleasant experience. After about year 2000 I can't handle all the electronics, so the cars have become disposable, but they do last a long time -- lots of good +100k mile examples on the road, you didn't see that in the 60's or 70's.
I read a book about 15 years ago (I think called "Chemical Evolution") which stated that the chirality of living organisms was determined during the "replicating molecule" stage in life's origins because some important chiral molecules are very, very slightly more stable in one enantiomer due to the asymmetry of the nuclear weak force. The math seemed convincing at the time, but I never checked the other references. Sorry I can't give more detail. Is this something which was dismissed by the biology community a long time ago?
Kepler detects planets by seeing periodic small drops in the brightness of the host star as the planet passes in front of it. That is only going to work for planets with a pretty short orbital period (I don't know the limit) since they depend on multiple observations to get the orbital characteristics. Neptune with is 100+ year period would not be measurable and unlikely to be observed even once during the mission.
The discussion here has the electron donors turned around. The "oxidant" such as oxygen takes the electrons from the reducing agent. Oxygen has 6 electrons in its outer shell and needs only 2 more to have a completely full outer shell, thus it has a strong attraction for those 2 more electrons and takes them from less electropositive elements such as metals. You sound like you know what you are talking about so this is probably just to point out a typo, but I post it to prevent confusion on the thread... I realize that covalent bonding such as in CO2 is a bit more complicated, but O is still considered the oxidizer there.
It appears you've never been in a real war. Neither have I but I've seen the pictures from WW I and WW II and read the statistics. You can academically say, "Well they were an inevitable event in the adaptation of 19th century nation-states societies to the 20th century Industrial Age", but that doesn't mean you want your kids to go through that sort of thing -- and I mean the devastation of WW II in Europe and Asia, not the relatively light touch the US got. I'll take a multi-hundred year climate change to which we can adapt over a ten year series of conflicts later called WW III.
Interestingly the 'start-stop' cycle you describe provides a thermodynamic advantage to the four stroke reciprocating engine over a turbine. Because the piston and valves get to be cooled off during the intake stroke they can tolerate higher combustion temperatures during the power stroke. Higher combustion temperature = higher thermodynamic efficiency. In a turbine the blades in the power section are continuously exposed to the hot gases of the combustion section which limits the maximum temperature the combustion can run at. Now there are a lot of other factors -- since the turbine has a separate compressor section from the power section, each can be optimized for its purpose, while a piston has to be a compromise, for example. Anyway, the whole issue of relative efficiencies between the different heat engines is a fascinating subject. I think everyone can agree that no one 50 years ago would have dreamed that piston engines could become as clean and efficient as they are now. As arcsimm points out in the earlier post no one has been able to improve on the reciprocating piston for the small, mobile installations of automobiles, not for lack of trying.
I'm not an expert either but these objects are loosely "captured" by the Earth due to interactions mostly with the Sun I think. Even without the Moon this can happen. If the Earth were totally isolated then this couldn't happen via Newtonian mechanics but the presence of the Sun makes the whole system a three body problem with chaotic effects such as temporary captures. The definition of "temporary" depends on your timeframe -- not much in the Solar System is eternally stable due to multi-body gravitational effects anyway.
Reasonable answer -- I was a bit harsh in my original reply but still pretty much disagree. Two points -- philosophically I like some sort of intake charge compression (turbo or supercharging) because of a basic imbalance in the way a reciprocating engine works -- you have hundreds of psi of exhaust pressure (pushed by the piston) to empty the cylinder but only atmospheric pressure (15 psi) minus throttle losses to fill it on each stroke -- that's why intake valves are always bigger than exhaust valves. Also with a turbo you are able to capture some of the waste heat in the exhaust stream increasing the basic thermodynamic efficiency of the engine. On the whole environmentalism issue -- you have to admit that the engines of 2012 are more powerful and drivable than the best engines of the glory days of the 60's, while being almost infinitely cleaner and considerably more efficient. Of course this is all technology driven but a bunch of that technology was forced by environmental requirements. Since about 1992 (when the new Chevy 5.7 liter LT-1 came out) the car makers have shown we can have it all -- clean, efficient engines and more power than than you can use on the street. This drive to even smaller displacements is just along the same trend as technology gets even better.
Nothing to be too sorry about -- a new 2012 Mustang with a 305hp V6 lists for $22,310 and is EPA rated at 31 mpg for highway fuel economy -- actually quite affordable, not that any compensation is necessary.
The guys that really know cars don't agree with you. When Motor Trend tested the 2011 Ford F-150 Pickups "the idea was to see whether it makes more sense for buyers to get the twin-turbo V-6 or the 5.0-liter V-8" (their quote). Continuing they said, "From the dyno and track results, the EcoBoost's performance data makes it a better rival for the 6.2 (liter V-8). The EcoBoost F-150 was fastest of the test..." The story is at http://www.motortrend.com/roadtests/trucks/1110_2011_ford_f_150_full_line_test/viewall.html. I've owned a variety of big block and factory turbocharged cars including the real good ones -- 427 'Vette, 6.6 Liter Trans Am, 455 Stage 1 Buick, 3.8 liter Buick Turbo-Regal, GMC Syclone 4.3 liter turbo V-6, Volvo 2.3 liter turbo I-5. The turbo cars were better all around performers than the big blocks -- just as fast and better in every other category. One reason is that with a small, lightweight engine the car can be lighter and better balanced. In a direct comparison, I had a hot-rodder friend who owned the following two cars -- '69 Camaro with a transplanted 427 (L88 427 -- the real factory race engine in the late 60's, 7 liters for the metric oriented reader) and an '86 Buick Regal T-Type with the turbocharged 3.8 liter V6. After some garage tweaks the Regal ran a faster 1/4 mile at the dragstrip than the Camaro, both in the 11's as I recall. And I remember guys breaking rods racing naturally aspirated V-8 cars all the time.
I'm going to have to pile on to you for the "fly-by-wire" comment. With personal experience in both types, I can tell you, fly-by-wire airplanes will do things which the old fashioned ones won't. For example, the F-16 is aerodynamically unstable -- a pilot without the help of the computers can't fly it. This built-in instability combined with the flight control computers gives the aircraft the ability to outmaneuver the old ones.
As I badly posted in a previous comment it was a direct derivative of the V2 which launched the first American satellite in 1958. V2 -> Redstone IRBM -> Jupiter C launch vehicle, all developed by Werner von Braun's engineering team.