One tradeoff though is that if you accelerate faster in the lower atmosphere, you run into higher dynamic pressures, making aborts harder. That said, Orion's LAS was sized based on outrunning "the Corndog", which had probably the worst max-Q I've ever seen for a proposed human launcher, so maybe it won't matter.
According to Steve's calcs, Pyrios has about 1.4 times the total thrust of the 5 segment booster...
Steven, you might be interested in a conceptual design and analysis computer program for rockets and their missions that I developed in retirement. It's called ZOOM and is free. It has a GUI and works with Windows XP, Windows 7, and Windows 8.1 operating systems. It can be used on tablet computers with touch-screens. It can be downloaded at:http://trajectorysolution.com/zoom-7.zipI first began developing rocket trajectory optimization programs in 1963 with Boeing in Huntsville, Alabama. We based our methods on the calculus of variations back then. As our simulations got more complicated we switched to parameter-optimization techniques. In 1973, at Northrop in Huntsville, I developed and used a method based on the Simplex algorithm (of Linear Programming fame) to define a quasi-optimum reentry trajectory for a Space Shuttle type vehicle. The objective was to minimize the aerodynamic heat load, and a limit was imposed on the aerodynamic heating rate. A modified version of that method is used by ZOOM.In my view, ZOOM is a powerful tool for conceptual design and analysis. It's really sort of a miracle.... working much better than my experience would have led me to expect.Best regards,David F. WilliamsHuntsville, Alabama, USA
Thanks very much David. I look forward to trying your software in order to verify my simulations.For the last few weekends, I have been updating my software to reflect the latest information on the RSRMV boosters, core, RS-25E engines and J-2X engines. There are some substantial payload increases due to the lighter core, higher thrust RS-25E and the long nozzle version of the J-2X. Below is a summary of the results. Attached are pdf's giving the details. The payloads given below are for a 200 km circular orbit where the payload also consists of an Orion crew vehicle.Name Boosters RS-25E J-2X Payload (t)--------------------------------------------------SLS1C4J1.1 RSRMV 4 1 113.6SLS1C5J2.1 RSRMV 5 2 130.6SLS1C6J2.1 RSRMV 6 2 137.0SLS2C4J2.1 2xF-1B 4 2 139.7SLS3C4J2.1 3xAJ1E6 4 2 142.9SLS4C4J2.1 ATK AB 4 2 131.5Of interest is that we can get 130 t payload (not IMLEO) using either Block I RSRMV boosters and a five engine core or with ATK Advanced Boosters (aka Dark Knights) with a Block I four engine core.
I put those numbers (SLS4C4J2.1) into Schilling's rocket calculator which gives me approx. 127t to LEO. Funny thing is, if I add 2 additional ATK ABs to the rocket it increases the payload by 45t to 172t.It that realistic?
Tom, the closest I have is Dark Knights, 4xRS-25E core and 2xJ-2X upper stage. I only got 124.8 t to LEO (9,787 m/s delta-V). The limiting factor here is the core thrust. It needs to be greater in order to reduce gravity losses. Going to five engines on the core reduces delta-V to 9,320 m/s with payload increasing to 144.1 t.