What about LH2-Fluorine? It's got superior Isp, and the Moon has no ozone layer or atmosphere to contaminate, and the mass savings it provides could be significant when lugging it all the way to the Moon.
Yeah, I know Fluorine is famously toxic, but would that matter so much on the Moon?..
Because going pump fed from no deep space flight heritage is simply infeasible, considering it hasn't been done before.State of the art of deep space main engines is still hypergolic, pressure fed.
Quote from: Robotbeat on 03/08/2017 11:01 amQuote from: savuporo on 03/07/2017 06:59 pmQuote from: sanman on 03/03/2017 10:05 pmWhat propulsion will it use?Not a pump-fed engine. Or an electric pump, perhaps.And why NOT pump-fed? Smaller pumpfed engines have been developed. The Fregat stage is pumpfed but half the thrust. Do you have any evidence that it's not pump-fed? If it's just your opinion, say so. Don't state it as if it's a fact.Because going pump fed from no deep space flight heritage is simply infeasible, considering it hasn't been done before.State of the art of deep space main engines is still hypergolic, pressure fed.
Quote from: savuporo on 03/07/2017 06:59 pmQuote from: sanman on 03/03/2017 10:05 pmWhat propulsion will it use?Not a pump-fed engine. Or an electric pump, perhaps.And why NOT pump-fed? Smaller pumpfed engines have been developed. The Fregat stage is pumpfed but half the thrust. Do you have any evidence that it's not pump-fed? If it's just your opinion, say so. Don't state it as if it's a fact.
Quote from: sanman on 03/03/2017 10:05 pmWhat propulsion will it use?Not a pump-fed engine. Or an electric pump, perhaps.
What propulsion will it use?
Fregat, which is the small pump-fed example I used, is as deep space as anything. I believe it can last for days in orbit in between burns, which is enough to go all the way to the Moon.
But of course more recent experience with vertical rocket landings on Earth (F9, New Shepard) suggest a different approach might be possible on the Moon as well, i.le. don't bother with hovering, just hoverslam onto the surface.
Quote from: savuporo on 03/09/2017 11:15 pmBecause going pump fed from no deep space flight heritage is simply infeasible, considering it hasn't been done before.State of the art of deep space main engines is still hypergolic, pressure fed.Theres no such thing as a "deep space main engine", the statement is meaningless. ..
how much imaging resolution will they have before hand to know they're not coming down on top of a big boulder, or other terrain they can't land on?
a miniSAR-equipped aircraft flying within 10 kilometers over a golf course "could resolve the fact that there were two golf balls 4 inches apart"
Blue Origin's Rob Meyerson discusses proposed "Blue Moon" lander for supplying lunar settlement under public-private partnership. #33SS
The concept as shown appears to be a cargo lander with legs that telescope but do not fold, and given the selections of launch vehicles, size, and energies required, is either hydrolox or methalox, handling LOI, PDI, landing, and possibly ascent/ EOI (if reused).Note the thrust can be accepted by an adapter at the top - perhaps the concept is to launch upside down, tanks and engine up. Such a concept could be adapted after the design matured for crew as well as cargo, with various additions including docking adapter.This design isn't well suited to sorties but more follows the model of Altair, FLO, and Russian reusable landers in terms of payload delivery and operations tempo.
Quote from: Space Ghost 1962 on 04/05/2017 08:23 pmThe concept as shown appears to be a cargo lander with legs that telescope but do not fold, and given the selections of launch vehicles, size, and energies required, is either hydrolox or methalox, handling LOI, PDI, landing, and possibly ascent/ EOI (if reused).Note the thrust can be accepted by an adapter at the top - perhaps the concept is to launch upside down, tanks and engine up. Such a concept could be adapted after the design matured for crew as well as cargo, with various additions including docking adapter.This design isn't well suited to sorties but more follows the model of Altair, FLO, and Russian reusable landers in terms of payload delivery and operations tempo.According to the Aviation Week article in March,
BE-3U handles TLI through PDI. Landing is handled by 11,000-lb methalox descent engines. The number of descent engines is scalable based on the launch vehicle.Edit: The phrasing in the Aviation Week article isn't particularly clear with respect to use of the BE-3U during descent and could possibly be interpreted as referring to LOI: "It [BE-3U] would retain enough capability after that to begin slowing the vehicle toward its target on the lunar surface, he said."
My comments (as I've highlighted above) are solely directed to the Rob Meyerson graphic.They likely don't apply to the Av week article. You'll have to ask Rob/BO to reconcile the two.
Please note significant discrepancies between these two.2) The vehicle does not show propulsion/engines - however, from sizing and leg extension, you can barely fit a BE-3U bell, and likely you'd desire a larger expansion ratio with an in-space propulsion, especially for TLI/LOI.