|
|
Thread Tools | Display Modes |
#41
|
|||
|
|||
NASA orbit simulation software
Dr J R Stockton wrote:
In sci.space.tech message , Wed, 20 May 2009 23:50:28, kevin willoughby . invalid posted: Pat Flannery wrote: kevin willoughby wrote: If two of three versions agree, that doesn't mean those two are correct. Though in this case you do get feedback by observing where exactly the satellite's orbit ended up in reality versus what one or more programs predicted. That works, but it can be a *very* expensive way to debug a program... Not necessarily expensive; it depends on the brightness of the satellite and the magnitude of the error. I'll stand by my statement. The test plan for a moderately complex program will specify several hundred test cases, minimum. Launching several hundred satellites. Until the cheap-access-to-space miracle occurs, we're talking a significant chunk of a gigabuck. -- Kevin Willoughby lid It doesn't take many trips in Air Force One to spoil you. -- Ronald Reagan |
#42
|
|||
|
|||
NASA orbit simulation software
kevin willoughby wrote: I'll stand by my statement. The test plan for a moderately complex program will specify several hundred test cases, minimum. Launching several hundred satellites. Until the cheap-access-to-space miracle occurs, we're talking a significant chunk of a gigabuck Ah, but there is something slick we can do here...we don't need to use satellites that are _going_ to be launched; we can backtrack and use ones that were _already_ launched. Unfortunately, we probably can't get our hands on all the detailed data for all that thousand or so Soviet optical and Signit recon satellites that were launched, but with some digging we certainly can come up with the details on the hundreds of satellites the US has launched since 1958, and enter those into the programs to see how accurately they predicted what would happen to them versus what really did. In the case of the numerous Corona satellites, they never did end up in exactly the intended orbits in the early days, and had to have their event clocks reset once on-orbit to tell them when to photograph things and when to release their film return capsules. Pat |
#43
|
|||
|
|||
NASA orbit simulation software
Pat Flannery wrote:
kevin willoughby wrote: I'll stand by my statement. The test plan for a moderately complex program will specify several hundred test cases, minimum. Launching several hundred satellites -- until the cheap-access-to-space miracle occurs -- we're talking a significant chunk of a gigabuck Ah, but there is something slick we can do here...we don't need to use satellites that are _going_ to be launched; we can backtrack and use ones that were _already_ launched. That would certainly be useful. But it wouldn't come close to filling in all the required test cases for a universal-orbit-calculator program. You'd need custom launches into extreme and/or weird orbits to complete the test plan. Perhaps the trickiest would be placing a satellite in (not orbiting) each of the Lagrange points. As far as I know, no one has ever done a sun-synchronous polar orbit around the moon. Buzz Aldrin hypothesized a cyclic traveler orbit between Earth and Mars. So I still say: we're talking a significant chunk of a gigabuck. Unfortunately, we probably can't get our hands on all the detailed data for all that thousand or so Soviet optical and Signit recon satellites that were launched, It wouldn't surprise me if that information was available. Perhaps the former USSR would be willing to sell that data. Or may NORAD could be convinced to declassify the data. But again, that doesn't eliminate the need to lots of launches to validate the software. The Soviet launches were all from high latitudes, and flew into a limited number of orbital planes. -- Kevin Willoughby lid It doesn't take many trips in Air Force One to spoil you. -- Ronald Reagan |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
NASA orbit simulation software | Joćo Gomes | Space Shuttle | 0 | May 14th 09 02:45 PM |
NASA seeks volunteers for a spaceflight simulation | Jacques van Oene | Space Shuttle | 8 | December 21st 05 10:37 PM |
NASA seeks volunteers for a spaceflight simulation | Jacques van Oene | Space Station | 8 | December 21st 05 10:37 PM |
Shuttle re entry simulation software? | Christopher | Policy | 4 | October 14th 03 05:38 PM |