mikelorrey
46p41 comments posted · 5 followers · following 0
5 years ago @ The Space Review: essa... - The Space Review: How ... · 0 replies · 0 points
If a Starship can get in 100 launches, thats useful for the Mars route, but for reliable ballistic use, they really need to get 1000 flights out of one airframe with phase inspections every 50-100 flights.
Anyways, assuming an airframe/engines cost of 50 million, at most, given plans for long term mass production, the amortized capital cost per flight should be around 1 million, and assuming the above study's per flight energy cost of $43k per seat, which should come to a fuel cost per flight of around 10 million. Even adding the capital cost onto the ticket, should be around 55-60k, then you have all the operations overhead to deal with: ground crew, flight crew, maintenance, management and administration, a 100k ticket price is perfectly reasonable.
Note that Concorde never lacked for customers, it only lacked for available routes it was allowed to fly by regulatory restrictions.
5 years ago @ The Space Review: essa... - The Space Review: The ... · 0 replies · +1 points
5 years ago @ The Space Review: essa... - The Space Review: A Sp... · 0 replies · +1 points
7 years ago @ The Space Review: essa... - The Space Review: The ... · 1 reply · +2 points
You can very easily make a two stage, reusable, LOX/Kerosene based RLV, and even make it a HTOL vehicle to enable airline-like flight operations. Isp is not the be-all, end-all of reducing launch costs or achieving reusable vehicles. Nor is this vehicle DARPA is proposing a SSLV, it clearly is a first stage vehicle intended to put an upper stage into an orbital injection trajectory only.
7 years ago @ The Space Review: essa... - The Space Review: The ... · 2 replies · +5 points
b) Sorry but your listing Kerosene/LOX as 250 seconds is fallacious. SpaceX Merlin 1D engines run just shy of 350 secs Isp.
c) The real problem with achieving reusable rockets is that engineers have been fixated on gravimetric Isp and not volumetric Isp. Aerodynamic losses are a much bigger factor, so fat hydrogen tanks impose an aerodynamic load that largely neutralizes, and in many cases, penalizes, hydrogen fuelled launch vehicles. This is why the Saturn V was kerosene/LOX on its first stage, else it would have been three times larger, and more expensive as a result by a similar ratio.
Going by volumetric Isp, it is clear that methane, MCH, kerosene, and more interesting fuels like cyclopropane and methylacetylene have much better performance because they are denser by far and thus what they save in smaller launch vehicle size (and thus lower lv dry mass as well) MORE than makes up for their gravimetric Isp being lower than hydrogen, because by volumetric comparison, hydrogen sucks!
7 years ago @ The Space Review: essa... - The Space Review: Is &... · 1 reply · +1 points
10 years ago @ The Space Review: essa... - The Space Review: MOL&... · 1 reply · 0 points
10 years ago @ The Space Review: essa... - The Space Review: Deci... · 3 replies · +11 points
11 years ago @ Center for a Stateless... - A (Brief) People's His... · 0 replies · +1 points
12 years ago @ Big Government - Occupy Wall Street Rap... · 0 replies · +7 points