My first thought: You need a reusable second stage to refuel a second stage in orbit.
With all the talk of what SpaceX can do with tankers and refueling, I'm curious what kind of payload a two stage New Glenn rocket from Blue Origin could send to TLI if the second stage could be refueled in LEO. Does anyone have a guess on how much mass it could push?
Would refueling eliminate the need for a three stage version?
Quote from: Eric Hedman on 10/06/2017 06:05 amWith all the talk of what SpaceX can do with tankers and refueling, I'm curious what kind of payload a two stage New Glenn rocket from Blue Origin could send to TLI if the second stage could be refueled in LEO. Does anyone have a guess on how much mass it could push? My estimates: 2nd stage dry mass: 20t.2nd stage prop mass: 270t.max LEO payload: 45t. Total refueled mass in LEO: 335t. Delta-v available with 365s BE-4U: 5870 m/s. Refueling launches required: 6. Total launches required: 7.So it could send to TLI as much as it could lift to LEO, and then some. In fact, it could get about 44 tonnes to TLI with just 2 fueling launches. So 3x New Glenn 2-stage > 1x SLS 1B to TLI.QuoteWould refueling eliminate the need for a three stage version?Expending 2nd stages to avoid expending 3rd stages is usually a bad idea, since 3rd stages are much smaller and cheaper. However, if you need 40+ tonnes to TLI, or they could figure out how to reuse the 2nd stage without a serious payload hit, then the 3 stage isn't as useful.
I wonder could Lockheed MDAV be used as a starting point on designing a reusable upper stage for New Glenn?As for moving payloads to higher orbits maybe a hybrid tug using chemical and SEP engines.
Or a derivative. It's hard to tell form the outside how well locked down the technology behind ACES is.Who has key patents, say for on orbit refueling. Are they exclusive to ULA at this time? Can they be worked around? Question to me is is what engine choices ULA makes and if they would license key technologies or even sell (lease? rent?) complete 7m class ACES stages to Blue. If that is if Blue has a use for such a 3rd stage in the first place. Perhaps they'll try something different, say refueling their 2nd stage with a reusable tanker. OTOH the BE-4U seems a bit large for an on orbit tug.