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James Webb Space Telescope vs SLS
Both the James Webb Space Telescope and SLS are scheduled for 2021. I
think that SLS has a higher likelihood of schedule slip than JWST because the purpose of that telescope is to do science and it can't do that science while on the ground. On the other hand the purpose of SLS seems to be to save jobs, and it can very well do that with schedule slips. But maybe that is only bias on my part. What do you people think? I haven't really kept tabs on science mission schedule slips at NASA. Are they common? Alain Fournier |
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James Webb Space Telescope vs SLS
On Thursday, September 12, 2019 at 1:15:38 AM UTC-4, JF Mezei wrote:
On 2019-09-11 19:41, Alain Fournier wrote: Both the James Webb Space Telescope and SLS are scheduled for 2021. https://jwst.nasa.gov/content/about/launch.html Launch Date Webb will launch in 2021. Launch Vehicle The James Webb Space Telescope will be launched on an Ariane 5 rocket. The launch vehicle is part of the European contribution to the mission. ... This isn't just a question of wanting the Telescope up there to do needed work, it is also a question that Ariann 5 being retired in 2022, so there is much motivation to get it launched in 2021. (The decision to laujch on Arianne 5 was taken in 2015 from what I read, so SLS has been out of the loop for quite some time now). Maybe Ariane 6 will be available by then. |
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James Webb Space Telescope vs SLS
"Alain Fournier" wrote in message ...
Both the James Webb Space Telescope and SLS are scheduled for 2021. I think that SLS has a higher likelihood of schedule slip than JWST because the purpose of that telescope is to do science and it can't do that science while on the ground. On the other hand the purpose of SLS seems to be to save jobs, and it can very well do that with schedule slips. But maybe that is only bias on my part. What do you people think? I haven't really kept tabs on science mission schedule slips at NASA. Are they common? Alain Fournier JWST will fly before SLS. It's finally at the point where it's basically flyable. And as you said, it's job is to do science, so launching it lets it do its job. SLS's job, even if it flies will be done cheaper by other methods. There's far less pressure on it to fly I think. -- Greg D. Moore http://greenmountainsoftware.wordpress.com/ CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net IT Disaster Response - https://www.amazon.com/Disaster-Resp...dp/1484221834/ |
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James Webb Space Telescope vs SLS
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James Webb Space Telescope vs SLS
Jeff Findley wrote:
In article , says... Yet, james Web was "assigned" to Arianne 5 in 2015, so there wouldn't have been any recent discussions of it going on SLS. That's because James Webb Space Telescope will be launched on an Ariane 5. The program is so expensive, NASA cut a deal with ESA to launch it, no doubt in exchange for observation time on the telescope. While NASA is the lead agency on JWST the project has AFAIK always been based on having major contributions from European Space Agency[1] and the Canadian Space Agency[2]. As an example, there's four main instruments and one of these provided via NASA, one via ESA and one via CSA with the final being a cooperation between NASA and ESA. And arguably the FGS (that keeps JWST on target) that CSA provides is almost an instrument so one could almost argue they provide "1.5" instruments each :-) Also listed in the ESA document are the launch and "part of the operations team" (I'm assuming both before launch and operationally afterwards). I expect that NASA is the biggest single contributor, likely even the majority contributor but it's hard to find any real figures (and those figures would by necessity be very fuzzy too). parity error in my memory? or is SLS still planned to use one of its limited rockets to launch a scientific payload to somewhere? Europa Clipper, not JWST. IIRC it's still supposed to be launched by SLS (by senate funding requirement) because only SLS can send it in a direct trajectory to Jupiter. There's been some recent attempts to try to move this to a commercial launcher instead to save (lots of) money with predictable blow-back from the senate proponents for SLS. I think these are merely trial balloons, preparing for if (or perhaps when) Europa Clipper is getting close to being ready and SLS isn't, the real discussion can take place because it'll be hard to dismiss as "mere" speculations. Apparently an expendable Falcon Heavy with a STAR 48BV? kick-stage can do it with one gravity assist and Falcon Heavy and Delta IV Heavy can do it with three gravity assists without a kick stage. The three gravity assist version is going to be a lot slower than the SLS direct trajectory (6-7 years vs 2-3 years depending on which launch window used), the single gravity assist trajectory is clearly going to be faster than the 3 assist one but I've not seen actual timings on that trajectory. 1. https://sci.esa.int/web/jwst/-/45728-europe-s-role 2. http://www.asc-csa.gc.ca/eng/satelli...ntribution.asp |
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James Webb Space Telescope vs SLS
In article , lid says...
Jeff Findley wrote: In article , says... Yet, james Web was "assigned" to Arianne 5 in 2015, so there wouldn't have been any recent discussions of it going on SLS. That's because James Webb Space Telescope will be launched on an Ariane 5. The program is so expensive, NASA cut a deal with ESA to launch it, no doubt in exchange for observation time on the telescope. While NASA is the lead agency on JWST the project has AFAIK always been based on having major contributions from European Space Agency[1] and the Canadian Space Agency[2]. As an example, there's four main instruments and one of these provided via NASA, one via ESA and one via CSA with the final being a cooperation between NASA and ESA. And arguably the FGS (that keeps JWST on target) that CSA provides is almost an instrument so one could almost argue they provide "1.5" instruments each :-) Also listed in the ESA document are the launch and "part of the operations team" (I'm assuming both before launch and operationally afterwards). I expect that NASA is the biggest single contributor, likely even the majority contributor but it's hard to find any real figures (and those figures would by necessity be very fuzzy too). Agreed. This is not unlike how ISS is run, except that with JWST there aren't as many contributors at an international level (you listed them all). https://jwst.nasa.gov/content/meetTheTeam/team.html parity error in my memory? or is SLS still planned to use one of its limited rockets to launch a scientific payload to somewhere? Europa Clipper, not JWST. IIRC it's still supposed to be launched by SLS (by senate funding requirement) because only SLS can send it in a direct trajectory to Jupiter. True, but the Congress can change its mind. There's been some recent attempts to try to move this to a commercial launcher instead to save (lots of) money with predictable blow-back from the senate proponents for SLS. I think these are merely trial balloons, preparing for if (or perhaps when) Europa Clipper is getting close to being ready and SLS isn't, the real discussion can take place because it'll be hard to dismiss as "mere" speculations. More than a trial balloon. The NASA's inspector general has pretty much recommended commercial launch because it would save the US taxpayers nearly $1 billion. NASA inspector general asks Congress for Europa Clipper launch flexibility by Jeff Foust - August 28, 2019 https://spacenews.com/nasa-inspector...ss-for-europa- clipper-launch-flexibility/ Apparently an expendable Falcon Heavy with a STAR 48BV? kick-stage can do it with one gravity assist and Falcon Heavy and Delta IV Heavy can do it with three gravity assists without a kick stage. The three gravity assist version is going to be a lot slower than the SLS direct trajectory (6-7 years vs 2-3 years depending on which launch window used), the single gravity assist trajectory is clearly going to be faster than the 3 assist one but I've not seen actual timings on that trajectory. 1. https://sci.esa.int/web/jwst/-/45728-europe-s-role 2. http://www.asc-csa.gc.ca/eng/satelli...ntribution.asp The use of Falcon Heavy with a kick stage is surely the way to go. These kick stages are pretty much "off the shelf" and are considered part of the payload, as far as the launch vehicle is concerned. There are many NASA missions which have used such kick stages in the past, so it's a proven way to provide more velocity for a mission such as this. Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
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James Webb Space Telescope vs SLS
In article ,
says... On 2019-09-15 20:13, Torbjorn Lindgren wrote: There's been some recent attempts to try to move this to a commercial launcher instead to save (lots of) money with predictable blow-back from the senate proponents for SLS. What difference would it make? They have limited number of SLS flights, so if one doesn't do the Europa Clipper, it will be used for another type of unmanned test flight and the same amout of pork $ will be spent. NASA inspector general asks Congress for Europa Clipper launch flexibility by Jeff Foust - August 28, 2019 https://spacenews.com/nasa-inspector...ss-for-europa- clipper-launch-flexibility/ From above: NASA's inspector general says the agency could save nearly $1 billion if Congress gives it the ability to choose the best launch vehicle for a mission to Jupiter's moon Europa, rather than mandating the use of the Space Launch System. So, the difference is that by using a commercial launch vehicle, the US taxpayer would save nearly $1 billion. And it would eliminate the schedule uncertainty inherent with an SLS launch (considering this Administration's emphasis on Artemis, which "needs" SLS). Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
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James Webb Space Telescope vs SLS
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