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Indian Launchers / Re: Mangalyaan gets to Mars on first try
« Last post by TheVarun on Today at 05:20 AM »
 ^Thanks Abhishek!  I was about to post a message about 4 exact years in orbit for Mangalyaan/MOM. What an achievement. I wish they had shown some more recent pics of Mars, the last one publicly shown was in March. It's about time for a new series!
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The exact year doesn't matter.

The important bit is that Musk believes that this level of base is within the immediate plan - he sees a way to build and finance it.

If 2028 depends on a 2022 first trip, and if the date means "hardware for the base delivered to the surface", then this base was delivered on synod 4.

We already know the first two have 2 and 4 ships, and that none of the ships will fly back until synod 6, and so synod 8 is still mostly new ships.

This to me means he intends to build LOTS of ships. If I could ever sneak a question in, it would be "how many ships/yr would the factory be producing in the coming years"

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ABCD: Always Be Counting Down

That fits with the earth point to point idea. BFSs not just gas and go reusable like airliners but produced continuously in similar quantities at similar cost. Theyre just airliners that happen to also be capable of going to the moon or Mars.
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Can we keep this thread to discussion of the viewing complex?  Offshore launches have been heavily discussed in the Boca Chica thread.  Search in there -- you'll probably have to go back to Thread 7.  And yes I understand visibility of the offshore platforms fits this thread, but otherwise, take it over there please? :)
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Blue Origin / Re: BE-4 Reverse Engineered
« Last post by Rabidpanda on Today at 04:45 AM »
I am so out of my depth in this thread, but my layperson brain tells me that another major difference between Raptor and BE-4 is that the latter is not a closed system, whereas the former is functionally closed.

What?
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2028



Quite the exchange.

And what are we looking at?  If Mars Base Alpha is to be realized by 2028, we might be looking at a mining camp.  One conceivable schedule, leveraging the 12 cargo bays of the new aft cargo system:



1.  Early 2023 - Cargo ship aerobrakes at Mars into elliptical capture orbit, and deploys a trio of gamma-ray metal prospecting smallsats (<180 kg) from aft cargo.

2.  Ship lands and smallsats circularize to LMO.

3.  Early 2024 - Smallsats complete initial metal survey of Mars.

4.  Assuming metal-rich prospects are found, a drone survey is undertaken.  Drones might be small-payload helicopters patterned after the Mars 2020 AeroVironment drones.  The ship deploys from aft cargo a trio of meter-scale gamma-ray drones after Parshin et al. 2018, and a trio of magnetometer drones after Cherkasov & Kapshtan 2018.



5.  Late 2024 - Drones complete detailed surveys of the richest prospects, mapping ore surface distributions and precious-metal concentrations.  (Conceivably the LMO smallsats act as relays to get the data to Earth.)

6.  The ship deploys from aft cargo a trio of sampler drones, each equipped with electromagnet and sample tray.  Drones collect many small ore samples from the richest prospects.

7.  Early 2025 - Sampler drones return to the ship, laden with ore payloads that await retrieval by the first crew.

8.  Early/Mid 2025 - The first crew retrieves ore samples and performs physical assay, to verify precious metal concentrations and, potentially, stake mining claims.

9.  SpaceX auctions membership in the mining consortium.  This assembles expertise, establishes a joint legal office, and raises the financing required to build out ships and cargo for the first mining camp.

As for the mine itself, something like the notional Red Gold open-pit, open-air system is proposed.

10.  Mid 2027 - The second crew lands near the best mining prospect and begins siting and assembly of the mining camp - Mars Base Alpha.

Refs.

Cherkasov, S., & Kapshtan, D. (2018). Unmanned Aerial Systems for Magnetic Survey.

Parshin, A. & Grebenkin, N. & Morozov, V. & Shikаlenko, F. (2018). FIRST RESULTS OF A LOW-ALTITUDE UAS GAMMA SURVEY BY COMPARISON WITH THE TERRESTRIAL AND AERIAL GAMMA SURVEY DATA. Geophysical Prospecting. 66. 
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Splinter thread...

Just re-emphasising my caveat. Space hotels won't be as cheap as you're talking about for at least a decade or more.  The currently cheapest quoted figure (that I know about) is the BA330, which is supposed to rent out 1/3 the station at $25 million for 60 days, so not sure where you're getting your figures from?

That's not gunna make any sense when there's a vehicle that can carry 100 (or more!) people into orbit for $10M or less.

Consider the BA 2100 which could be launched on BFR. 2,250 m3 of internal volume is about double the volume of the BFS. So it's reasonable to say that Bigelow will have to beat the production and opportunity cost of two BFS vehicles. When you consider that SpaceX could just leave Mars-bound vehicles in orbit to act as hotels, perhaps to do on-orbit training of future settlers, it doesn't seem like a viable proposition.

I think the idea of a bare-bones "research station" or sure-it-sucks-but-you're-in-space hotel doesn't work at all if BFR starts flying. To compete a would-be space hotelier will have to offer a tailored experience - a real space spa and resort with zero-g swimming pool and sports arena or whatever. I think this suggests something other than expandables, but that might still be a good start.

True that only one has double the volume of the BFR, but if they develop a hub/node, they could potentially have 5 to 6 at the ones locations, that would be 10-12 times the volume of a BFR and more flexible in its layout as they don't have to come back down.
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SpaceX BFR - Earth to Deep Space / Re: BFR GTO capability
« Last post by su27k on Today at 04:19 AM »
If the BFS can do the mission itself then that's probably optimal. Otherwise a tug would seem the only solution if you want the business. One thing to take into account is that with a tug you may be able to launch two (or more) satellites into GTO with one launch of the BFS (one tug or two?). Also, a tug might be useful for more missions than GTO satellite launching. I expect this will be one of those times for some cost optimisation calculations.

NB. The tug doesn't have to come back to the same BFS. It could be picked up by a later launch (though this may coincidentally be the same actual craft).

I don't see a tug anytime soon, especially given the much reduced GTO market. Just use orbital refueling as BFS is designed to do, there's nothing wrong with it. It would take a few more hours but a GTO mission on Proton would take 7+ hours anyway, so it's nothing new. SpaceX can offer a better GTO injection performance to offset the perceived risk.
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Brian Eno who produced this for Starmus would be a good candidate:


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Blue Origin / Re: BE-4 Reverse Engineered
« Last post by vaporcobra on Today at 04:05 AM »
I am so out of my depth in this thread, but my layperson brain tells me that another major difference between Raptor and BE-4 is that the latter is not a closed system, whereas the former is functionally closed.
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IIRC what made the ice that the shuttle so much worse, was that it was tank insulation foam combined with ice. IIRC, the foam and ice made a kind of composite structure that was much less brittle than just ice alone. Also meant larger pieces.

Exactly, it's the foam did it, not the ice. Also at the time of the foam strike, Columbia was accelerating at 2g, when they tested the foam strike, the speed used was above 200 m/s.

An ice piece falling at liftoff would have a much lower speed, and it would be from a fairly low height since the top 1/3 of the ship is the cargo bay which has no ice. Free fall speed from 33m height is only about 25 m/s.

Also need to remember Mars has much lower gravity so the impact speed there would be even lower.
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