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Old 02-01-2019, 01:19 AM
luke strawwalker's Avatar
luke strawwalker luke strawwalker is offline
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Continued...


Then there's the sad story of Galileo... Another mission that very nearly didn't happen because of shuttle costs, but finally squeaked by and managed to survive... BUT it TOO was *FORCED* to be launched by Shuttle, even though it didn't really make SENSE to do so, particularly since it was going to JUPITER. Galileo suffered YEARS of delays and was forced through several redesigns due to the INADEQUACIES of the shuttle... First, it was going to have to take "the long way around" using several Earth/Venus/Earth fly-by's to gain enough velocity via "the slingshot effect" to even make it to Jupiter, because at the time the ONLY booster rocket available to boost Galileo out of LEO was the IUS... which was WOEFULLY underpowered for the job. Basically all the IUS could do was put Galileo onto a "long track" multiple slingshot maneuver trajectory and required Galileo to get the rest of it's velocity from the planets themselves, adding YEARS to the travel time to Jupiter. So, after the spacecraft was basically mostly designed around this limitation, the "Shuttle Centaur" became available, and with a powerful twin-engine hydrogen-powered upper stage like Centaur to propel it, a direct injection from LEO to Jupiter became possible, shaving years and multiple planetary encounters off the trajectory to get to Jupiter. SO, the spacecraft was redesigned for this additional performance. Enhancements to the design were made, etc. Then Challenger happened, and the Shuttle Centaur got the ax, permanently. SO, it was back to the IUS, which meant a HUGE decrease in performance and a mad scramble to redesign the spacecraft, which was already being built by this time, to shave weight so IUS had a hope in hanna of launching it out of LEO. Launching on shuttle also meant no room for a large solid high-gain antenna like the Pioneers and Voyagers had used, not that they could spare the weight for one anyway, so they designed a complicated folding high gain antenna for Galileo. The spacecraft was finished and spent YEARS waiting for a launch slot due to the backlog of launches in the wake of Challenger, and when it finally DID get launched, it was into the "long way around' multi-slingshot-maneuver multiple planet encounter trajectory that would take YEARS longer to get to Jupiter. Basically before they launched it, there were concerns whether the high gain antenna would actually unfold and work as planned after remaining folded for YEARS on the ground and in space during the transit than it was designed for. Sure enough, when the high gain antenna was finally commanded to unfurl, it irretrievably jammed and for awhile it looked like the entire mission was ruined. The enterprising team on the ground, however, figured out a "work around" for the disabled high gain antenna, using the low gain antenna to "whisper" the data back across space from Jupiter, far more difficult to receive on Earth, but possible. The problem was, it was PAINFULLY SLOW because of the low data transmission rate, which was the only thing possible. Galileo recorded all the pictures and measurements it took, all the data it had collected, in on-board storage on the spacecraft, until it swung out away from Jupiter and could reorient it's antennas toward Earth and transmit the data and images back. Because of the slow transmission rates of the low-gain system 'work around' due to the shuttle-instigated failure of the high-gain antenna, only a FRACTION of the recorded data and images Galileo had taken could be sent back before it had to reorient itself away from Earth for the next pass... it basically just 'taped over' whatever hadn't had time to be sent back to Earth. Basically, OVER HALF of the data and images Galileo took at Jupiter were "recorded over" on the spacecraft and lost forever, due to the stupidity of INSISTING it be launched on shuttle. We'll never know how many DISCOVERIES were lost due to this.

Fortunately, by the time Cassini was being planned for Saturn, all such stupidity as *insisting* it be launched on shuttle was abandoned, and Cassini was given a proper UNMANNED booster.

There's a lot of other things I could mention... we lost Skylab because shuttle was delayed and its development problems and cost overruns left NO MONEY for even an unmanned tug mission to save it. Reagan's "Space Station Freedom" was a basket case of multiple redesigns, in large part because of being launched and serviced by shuttle, and difficulties arising from that choice. ISS has suffered a lot of the same problems. (Of course ISS was basically just SSF, but without the US having to develop the "hard parts"-- in-space refueling capability and a service and propulsion module for SSF-- instead after the collapse of the Soviet Union, it was now possible to BUY *their* technology that they had invented for their Salyut and Mir programs, paying their rocket scientists to modify the Mir II core into a service module as their contribution to the "International Space Station", leveraging their knowledge of automated rendezvous and docking for their Soyuz spacecraft and Progress space freighters and tankers to resupply and refuel the station, in addition to shuttle, and provide reboost propellant, water, and other consumables via in-space refueling; all things the US never bothered to develop and which would take a decade and cost BILLIONS for the US to do...

Without shuttle, we COULD have launched a space station of equal size on our own, out of five Skylab-size modules docked together. Not the 40 some-odd flights of the shuttle required to build ISS... and even then, ISS technically was never "finished"-- it simply reached "construction ceased" point when shuttle was retired and the remaining hardware now had no way to get to orbit so was scrapped or mothballed...

And, of course, each shuttle launch ended up costing MORE than a Saturn V launch, for about 1/5 the payload, if memory serves... basically the orbiter was correctly described as "a reusable 100 tonne manned payload fairing"... IOW, a BAD tradeoff...

Later! OL J R
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