I looked around and it appears that the OG-2 has a deltav capability of 140 m/s. From what I can tell the with a planned orbit of 350 x 700 km it was going to take about 110m/s to circularize at 700km. With only 140 m/s to use there is no way they can make it to the desired orbit.
Quote from: upjin on 10/08/2012 11:00 pmCan anybody make an educated guess on the orbit that the ORBCOMM's prototype OG-2 could possibly get to?And at this point it can't be said that SpaceX failed in regards to the OG-2 prototype, because it's not clear what it can't do at the lower orbit. It might be that it can complete all of it's tests at the lower orbit, or at least most of them and the important ones.I looked around and it appears that the OG-2 has a deltav capability of 140 m/s. From what I can tell the with a planned orbit of 350 x 700 km it was going to take about 110m/s to circularize at 700km. With only 140 m/s to use there is no way they can make it to the desired orbit.
Can anybody make an educated guess on the orbit that the ORBCOMM's prototype OG-2 could possibly get to?And at this point it can't be said that SpaceX failed in regards to the OG-2 prototype, because it's not clear what it can't do at the lower orbit. It might be that it can complete all of it's tests at the lower orbit, or at least most of them and the important ones.
Quote from: Jim on 10/08/2012 11:11 pmin generalJim... in general, how can one determine the amount of fuel left in a stage that is in free flight..?
in general
Quote from: cleonard on 10/08/2012 11:15 pmQuote from: upjin on 10/08/2012 11:00 pmCan anybody make an educated guess on the orbit that the ORBCOMM's prototype OG-2 could possibly get to?And at this point it can't be said that SpaceX failed in regards to the OG-2 prototype, because it's not clear what it can't do at the lower orbit. It might be that it can complete all of it's tests at the lower orbit, or at least most of them and the important ones.I looked around and it appears that the OG-2 has a deltav capability of 140 m/s. From what I can tell the with a planned orbit of 350 x 700 km it was going to take about 110m/s to circularize at 700km. With only 140 m/s to use there is no way they can make it to the desired orbit. Do you have a source for that?I believe they are required to keep 18 m/s for end of life disposal, so yes, they are out of luck if you are correct.
Hitchhikers might not always get to their ideal destination. Secondary means sacrificed if something arises that threatens the primary, in this case Dragon/ISS. Legal Rules of the road. Good for NASA, bad for SpX and Orbcomm. If this indeed is the case, lawyers scrapped a satellite, I would be PO'd.
Quote from: jcm on 10/08/2012 11:20 pmQuote from: cleonard on 10/08/2012 11:15 pmQuote from: upjin on 10/08/2012 11:00 pmCan anybody make an educated guess on the orbit that the ORBCOMM's prototype OG-2 could possibly get to?And at this point it can't be said that SpaceX failed in regards to the OG-2 prototype, because it's not clear what it can't do at the lower orbit. It might be that it can complete all of it's tests at the lower orbit, or at least most of them and the important ones.I looked around and it appears that the OG-2 has a deltav capability of 140 m/s. From what I can tell the with a planned orbit of 350 x 700 km it was going to take about 110m/s to circularize at 700km. With only 140 m/s to use there is no way they can make it to the desired orbit. Do you have a source for that?I believe they are required to keep 18 m/s for end of life disposal, so yes, they are out of luck if you are correct.Nothing 100% definitive by any means.I found it mentioned here on NSF in another thread and a pdf that looks like it is from Sierra Nevada from a presentation in 2009. http://www.responsivespace.com/Papers/RS7/SESSIONS/Session%20III/3001_Mosher/3001C.pdf
I've read through this entire thread, and as far as I'm concerned, SpaceX is fully justified to launch the next F9 without any changes while they work on the issue. Why? TWA Flight 800.Now if Flight 800, instead of exploding, had merely blown out a section of fusilage and vented the center tank, and if the crippled 747 had completed its mission and landed safely with no loss of life...AND if all 747s were then grounded and inspected and upgraded before ever being allowed to fly again, THEN SpaceX could resonably be expected to behave in a similar fashion.But that never happend. A 747 exploded for no good reason, 400 people died, and the 747 fleet was never grounded. They were not inspected in a timely fashion, and it was 12 years later (2008) before final concensus was reached on a corrective action, with passengers flying unprotected the entire time. Unmodified 747s with potential fatal defects continue to fly thousands of passengers every day.When Flight 800 exploded there were probably a dozen loaded 747s around the world waiting for takeoff. None of the passengers were informed they may be sitting on a bomb, none were given a choice to change aircraft. Someone rolled the dice and gambled thousands of lives, because at that time in 1996 there was no indication that all 747s didn't have the same defect. There was no indication that every other 747 wouldn't do the exact same thing.There is a glaring double standard at work here which has never made an ounce of sense. Boeing never grounded the 747 which exploded, so why should SpaceX ground the F9 which didn't? Per established aerospace operating practice, SpaceX can launch the exact same unmanned rocket again while they work on the problem and consider this an isolated incident. They can implement their resolution sometime in 2024.Unless someone can explain why bags of M&Ms and clean underwear are more deserving of protection than living breathing human beings.
There is a glaring double standard at work here which has never made an ounce of sense. Boeing never grounded the 747 which exploded, so why should SpaceX ground the F9 which didn't?
It may be that the best way to view the present SpaceX launch is as mostly successful, with some significant issues.
About the damage done by the accident, did someone noticed that the view we have of the octopus manifold shows no signs of damage ?It's few inches away from the engines.
Unless someone can explain why bags of M&Ms and clean underwear are more deserving of protection than living breathing human beings.
Playing spot the parts.. not sure if this has been completely played out yet...My guess.. [ Images sourced from NSF ]
the only thing at this point is they are going to try to do is change the orbit to more of a circular orbit which will buy a few months of operation. Right now it is in an elliptical orbit. They are going to try to use the small amount of remaining fuel to do this. If it is not sucessfull then it will plummet in a few weeks. if sucessfull then maybe three months. evidently its average height is about what the space station is. Not good enough. The Orbcomm is working so well they had to attenuate it. it is overloading the system