RGClark
Mathematician
- Joined
- Jan 27, 2010
- Messages
- 1,635
- Reaction score
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- Points
- 36
- Location
- Philadelphia
- Website
- exoscientist.blogspot.com
It is my contention that SSTO's are possible now and have been for decades. See the discussion in this thread: An SSTO as "God and Robert Heinlein intended" . This is no mere theoretical fact. It is also my contention that if SSTO's are instituted then the cost to orbit can be cut to a few hundreds of dollars per kilo.
In the posts to that thread, I gave estimated delta-V calculations based on the rocket equation for how mix and matching various existing components or components we had in the past you could get a SSTO. However, I would like to get a more accurate and convincing demonstration of this.
Anyone want to try to do an orbiter simulation of how you can get a SSTO using highly weight optimized stages with the engines swapped out to use the highest average Isp, sea level to vacuum, engines available now?
I'm especially interested in what average Isp you can get for your trajectory, and what is the minimum delta-V you need both for kerosene fueled and hydrogen fueled SSTO's. For instance in that thread on SSTO's I used an estimate that the trajectory-averaged Isp was 2/3rd's of the way from the sea level value to the vacuum value. I'm fairly sure though that this underestimates the average Isp you can get with a good trajectory. For instance this estimates the average Isp of the SSME's as 425 s. However, I've seen an estimate by a NASA official that it was in the range of 437 s. And I've confirmed this myself by numerically integrating the SSME thrust values according to altitude calculated from the altitudes values given on this page:
typical Shuttle / ISS Mission launch track.
http://www.orbiter-forum.com/showthread.php?p=33293&postcount=8
and getting a value in the upper 430's for the average Isp.
Bob Clark
In the posts to that thread, I gave estimated delta-V calculations based on the rocket equation for how mix and matching various existing components or components we had in the past you could get a SSTO. However, I would like to get a more accurate and convincing demonstration of this.
Anyone want to try to do an orbiter simulation of how you can get a SSTO using highly weight optimized stages with the engines swapped out to use the highest average Isp, sea level to vacuum, engines available now?
I'm especially interested in what average Isp you can get for your trajectory, and what is the minimum delta-V you need both for kerosene fueled and hydrogen fueled SSTO's. For instance in that thread on SSTO's I used an estimate that the trajectory-averaged Isp was 2/3rd's of the way from the sea level value to the vacuum value. I'm fairly sure though that this underestimates the average Isp you can get with a good trajectory. For instance this estimates the average Isp of the SSME's as 425 s. However, I've seen an estimate by a NASA official that it was in the range of 437 s. And I've confirmed this myself by numerically integrating the SSME thrust values according to altitude calculated from the altitudes values given on this page:
typical Shuttle / ISS Mission launch track.
http://www.orbiter-forum.com/showthread.php?p=33293&postcount=8
and getting a value in the upper 430's for the average Isp.
Bob Clark