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Difference between american and russian launchrocket technology.
Hi!
I have been following space related stuff since the 60's. It seems to me to look like russian spacelaunch vehicles accelerate faster than the big american launch rockets. I wonder if there is any significant scientific or technical difference in the way the russians and the americans go about when they launch manned spaceflights(and other flights)? K. Larsen, Norway |
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Difference between american and russian launchrocket technology.
"lapzilla" wrote in message news:AqGmb.2439$2o2.18102@amstwist00...
Hi! I have been following space related stuff since the 60's. It seems to me to look like russian spacelaunch vehicles accelerate faster than the big american launch rockets. Not necessarily. Soyuz FG and Proton have initial thrust/weight (T/W) ratios in the 1.3 to 1.4 range. It is true that Atlas V/401 and Delta IVM both crawl off their pads with T/W of about 1.2, but most U.S. launchers use strap-on solid rocket motors, which produce optimum results at higher T/W. For example, Delta 7920 has T/W of about 1.56. I wonder if there is any significant scientific or technical difference in the way the russians and the americans go about when they launch manned spaceflights(and other flights)? IMO, the Russians have the U.S. (and everyone else) beat in several ways. First, their rockets use straightforward, standardized designs. For example, Soyuz TMA-3, launched last week, used the 1,683rd R-7 rocket. The first two stages of that vehicle have changed little from Korolev's original 1957 design. About a dozen different R-7 based variants have flown. The design is undisputedly sound - only 96 R-7 based launches have failed over the years (and many of the failures involved upper stages, not the R-7 vehicle itself). In contrast, the most-often-used U.S. launcher is the Thor-Delta series, which has flown only 678 times altogether, with about 88 failures (including suborbital IRBM tests and Japanese-licensed launches). Amazingly, at least 89 different Thor-based configurations have flown (by my rough count). Not suprisingly, the most oft-flown configuration (Delta II) has been the most successful. Second, the Russians use streamlined launch processing techniques that are matched only by NPO Yuzhoye's Ukrainian Zenit. Their launchers don't use hazardous strap-on solid rocket motors, allowing them to be assembled and checked out horizontally on a railcar transporter. Soyuz is transported to its pad only two days before launch. Proton, a Saturn IB sized powerhouse rocket, is on its pad only one or two days more than Soyuz. (Zenit can be erected only hours before launch - that is why it was able to be adapted for Sea Launch use). Although the new U.S. EELV and European Ariane 5 launchers use improved launch processing techniques, both are still hamstrung by solid rocket hazards (which, as Alcantara reminded everyone recently, are all too real). Delta IV will still need 2-3 weeks on the pad before launch. Atlas V and Ariane 5 both move to the pad just before launch, but since both use solid motors, their vertical integration requires them to occupy their mobile launch platforms for weeks (unlike Soyuz, which is actually lifted onto its launch/transport platform only a few days before launch.) Russia's rockets have proven themselves again this year. Soyuz provided the only access to ISS while Proton quietly wrested control of the commercial launch market, winning more launch contracts than Arianespace this year. I think the world has much to learn from the Russians, who are, after all, the world's most experienced spacefarers. - Ed Kyle |
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Difference between american and russian launchrocket technology.
Thank you Ed for an instructive contribution!
I would like to know a little bit more, so I wonder if there are stuff available online. If not, maybe you can point me to some literature? K. Larsen "ed kyle" wrote in message om... "lapzilla" wrote in message news:AqGmb.2439$2o2.18102@amstwist00... Hi! I have been following space related stuff since the 60's. It seems to me to look like russian spacelaunch vehicles accelerate faster than the big american launch rockets. Not necessarily. Soyuz FG and Proton have initial thrust/weight (T/W) ratios in the 1.3 to 1.4 range. It is true that Atlas V/401 and Delta IVM both crawl off their pads with T/W of about 1.2, but most U.S. launchers use strap-on solid rocket motors, which produce optimum results at higher T/W. For example, Delta 7920 has T/W of about 1.56. I wonder if there is any significant scientific or technical difference in the way the russians and the americans go about when they launch manned spaceflights(and other flights)? IMO, the Russians have the U.S. (and everyone else) beat in several ways. First, their rockets use straightforward, standardized designs. For example, Soyuz TMA-3, launched last week, used the 1,683rd R-7 rocket. The first two stages of that vehicle have changed little from Korolev's original 1957 design. About a dozen different R-7 based variants have flown. The design is undisputedly sound - only 96 R-7 based launches have failed over the years (and many of the failures involved upper stages, not the R-7 vehicle itself). In contrast, the most-often-used U.S. launcher is the Thor-Delta series, which has flown only 678 times altogether, with about 88 failures (including suborbital IRBM tests and Japanese-licensed launches). Amazingly, at least 89 different Thor-based configurations have flown (by my rough count). Not suprisingly, the most oft-flown configuration (Delta II) has been the most successful. Second, the Russians use streamlined launch processing techniques that are matched only by NPO Yuzhoye's Ukrainian Zenit. Their launchers don't use hazardous strap-on solid rocket motors, allowing them to be assembled and checked out horizontally on a railcar transporter. Soyuz is transported to its pad only two days before launch. Proton, a Saturn IB sized powerhouse rocket, is on its pad only one or two days more than Soyuz. (Zenit can be erected only hours before launch - that is why it was able to be adapted for Sea Launch use). Although the new U.S. EELV and European Ariane 5 launchers use improved launch processing techniques, both are still hamstrung by solid rocket hazards (which, as Alcantara reminded everyone recently, are all too real). Delta IV will still need 2-3 weeks on the pad before launch. Atlas V and Ariane 5 both move to the pad just before launch, but since both use solid motors, their vertical integration requires them to occupy their mobile launch platforms for weeks (unlike Soyuz, which is actually lifted onto its launch/transport platform only a few days before launch.) Russia's rockets have proven themselves again this year. Soyuz provided the only access to ISS while Proton quietly wrested control of the commercial launch market, winning more launch contracts than Arianespace this year. I think the world has much to learn from the Russians, who are, after all, the world's most experienced spacefarers. - Ed Kyle |
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Difference between american and russian launchrocket technology.
Second, the Russians use streamlined launch processing techniques ...
assembled and checked out horizontally on a railcar transporter. Soyuz is transported to its pad only two days before launch. BRBR What size of launch crew is needed to assemble and fire this thing? Matt Bille ) OPINIONS IN ALL POSTS ARE SOLELY THOSE OF THE AUTHOR |
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