Electroman
Well-Known Member
Plus the impact of the exhaust due to lack of flame trench.
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the test appeared to go as planned, with no significant visual problems other than some tiles falling off the vehicle during the extended test. Tile liberation during these static fire tests is expected as the vehicle is held to the ground and vibrations move and reflect over the whole structure, causing tiles to likely move out of their pin sockets and fall away.
On top of that, the engine ignition shock reflection with the ground also affects the tiles as such shock hits back on the vehicle and may knock them loose or even break them. A glaring example of this issue can be found on the Space Shuttle’s first mission, STS-1.
On this mission, the solid rocket booster (SRB) ignition shock knocked tiles off the orbiter’s aft end right at liftoff. This was later linked to an underestimation of the amount of water deluge needed for sound suppression for the SRBs, which was then corrected for subsequent flights.
Perhaps coincidentally, it may seem like work is ongoing at the Starship OLM to upgrade the water deluge system. New flexible pipes have been added to the outside, and the root of this system connects to the iron water pipes that lead to the OLM from one of its legs.
There has been a lot of discussion in the NSF forum about what is happening with S26 and S27. I of course have no special insight into what SpaceX’s plans are for those vehicles, but I have a slightly wild theory; they are HLS prototypes that will be sent to lunar orbit sometime in 2023 and used for the first lunar landing attempts (uncrewed, obviously). It’s the only reason I can think of for building a Starship without tiles or flaps. The HLS vehicle will never re-enter Earth atmosphere and does not require tiles or flaps to land on the Moon.As previously reported, Ship 26 and Ship 27 may be undergoing a radical change in plans, omitting thermal protection system (TPS) tiles and not installing aerodynamic flaps. So far, this seems to be holding true with parts of Ship 26 seen now bare of tiles and on stand-by at Starbase’s ring yard for stacking.
Ship 27 parts are also proceeding similarly to Ship 26 parts. In some cases, there seems to be a strange mix-match of parts for these vehicles.
Could be orbital test tanks for refueling developmemt. HLS needs legs and high mounted supplementary engines.From the same NSF article:
There has been a lot of discussion in the NSF forum about what is happening with S26 and S27. I of course have no special insight into what SpaceX’s plans are for those vehicles, but I have a slightly wild theory; they are HLS prototypes that will be sent to lunar orbit sometime in 2023 and used for the first lunar landing attempts (uncrewed, obviously). It’s the only reason I can think of for building a Starship without tiles or flaps. The HLS vehicle will never re-enter Earth atmosphere and does not require tiles or flaps to land on the Moon.
What I don’t know is if an HLS Starship with no payload can, after reaching LEO, then do the TLI burn and then the de-orbit and landing burns to reach the lunar surface. For the lunar landing test missions it won’t require fuel to launch from the surface back into lunar orbit, the vehicle can just be left on the surface.
Or will it need to be re-fueled with a tanker Starship while still in LEO, before the TLI?
Good points. Though right now we can’t rule out SpaceX adding legs and retro-rockets to S26 and S27, which are not yet completed. Or maybe the objective for the first two HLS test flights will simply be to get the vehicles to lunar orbit, and test landings will come later.Could be orbital test tanks for refueling developmemt. HLS needs legs and high mounted supplementary engines.
Yeah, I was thinking the depo ships that just orbit and get refilled by multi-launch tankers then fill the cargo/ people carriers.Good points. Though right now we can’t rule out SpaceX adding legs and retro-rockets to S26 and S27, which are not yet completed. Or maybe the objective for the first two HLS test flights will simply be to get the vehicles to lunar orbit, and test landings will come later.
If those vehicles are planned to become prototype tanker Starships, they will need to be designed for re-entry and landing. I suppose they could be used only to test in-orbit refueling procedures and then they will be de-orbited into the ocean, like an F9 second stage.
I did not realize that a “depo ship” was part of the SpaceX in-orbit refueling plan. I thought that a tanker Starship went to LEO, transferred its extra O2/CH4 to a Starship and then returned to Earth.I was thinking the depo ships that just orbit and get refilled by multi-launch tankers then fill the cargo/ people carriers.
If you have a depot ship then you can know ahead of time that your cargo/ crewed ship can be refueled and the refurling can be done in one transfer. Otherwise, the cargo/ crew ship has to wait for and mate with 6 or however many tankers that each get launched after it.I did not realize that a “depo ship” was part of the SpaceX in-orbit refueling plan. I thought that a tanker Starship went to LEO, transferred its extra O2/CH4 to a Starship and then returned to Earth.
What is the advantage of having a depo ship in orbit? It adds an additional step in the process of refueling a Starship before it leaves Earth orbit to go on to the Moon or Mars, and it means keeping O2/CH4 in orbit longer which means more boil off.
Later, someone mentioned it looked like they were installing more bracing on the ship.Don’t know what the significance of this is…
You nailed it. The article at wccftech.com says:If you have a depot ship then you can know ahead of time that your cargo/ crewed ship can be refueled and the refurling can be done in one transfer. Otherwise, the cargo/ crew ship has to wait for and mate with 6 or however many tankers that each get launched after it.
Depot will have sun shades, radiators or such; but even without those, it's boil off (during active operations) would be similar to the cargo ship loitering.
Today's research paper, submitted by NASA officials to the IAC, shares details on the agency's plans for the Artemis 3 mission. It outlines that as part of Artemis 3, astronauts will take to the skies from Earth in the SLS, onboard the Orion spacecraft. However, before this happens, Starship will first launch its propellant depot to orbit, followed by tanker Starships to fill the depot. Once the depot is filled, the lunar Starship variant will lift off, fuel from the depot and then start its journey to the near rectilinear halo orbit (NRHO) after performing a trans lunar injection.
This it?In a new paper from NASA about HLS and Artemis 3 there are images of the three Starship versions that will be part of the mission. I read about the paper on wccftech.com. That article includes this link Search - NASA Technical Reports Server (NTRS) but I can’t find the actual NASA paper.
This is from the NASA paper. It is the first time I’ve seen an image of the Starship Depot vehicle.
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Well.... I repeated it at least...You nailed it. The article at wccftech.com says:
Ideally the orbital booster would have vacuum-optimized engines. I wonder about literally stacking two full-size boosters on top of each other for Earth launch, with the top booster only partially fueled, with vacuum engines and a nosecone. Just enough to get to orbit with no payload, then refuel there, and then attach an ordinary Starship on top. I wonder what sort of missions could be enabled this way?Well.... I repeated it at least...
A somewhat original thought I have had is to use a depot ship at an orbital first stage to increase useful mass and/or residual fuel of the cargo/ crewed Starship.
Need to rerun numbers to see how useful trading tanker launches for cargo is. At the exteme, if they could single stage a booster to orbit, it seems like at least 2km/s is possible with return. Starship solo is ~7km/sec.
Could also push a depot for remote refueling before in situ gets up and running.
Double stacked booster is basically booster + depot. Yah, depot doesn't need sea level engines.Ideally the orbital booster would have vacuum-optimized engines. I wonder about literally stacking two full-size boosters on top of each other for Earth launch, with the top booster only partially fueled, with vacuum engines and a nosecone. Just enough to get to orbit with no payload, then refuel there, and then attach an ordinary Starship on top. I wonder what sort of missions could be enabled this way?
While we're at it, what would stop one from stacking multiple such boosters on-orbit serially? Thinking of the super-long ship from 2001: A Space Odyssey. Could you make, say, a five-booster stack on-orbit, with a single Starship on top? That should enable some pretty quick trips through the solar system! And perhaps even reusable, if the boosters could retain enough fuel to get themselves back to reasonable orbits.
No question the rocket equation is tyrannical. Maybe a five-booster stack would have twice the total delta-v of Starship alone, for a reasonable-size payload. But twice is still a lot! Sample-return from Pluto?Double stacked booster is basically booster + depot. Yah, depot doesn't need sea level engines.
Additional stages of orbital boosters run into the same problem of diminishing returns as typical rockets as regards fuel. More mass to accelerate with each so decreasing gains.
Sadly, delta-v is a log function...
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Ultimately it may make more sense to make e.g. a large ion-engine booster rather than a standard methalox one, although it couldn't assist in launching itself to orbit unless it were a hybrid booster with both ion engines and Raptors. Or one could launch it hybrid, then remove the raptors on-orbit to reduce mass, and refill the tanks with e.g. krypton. No shortage of potential solutions. But of course, let's get ordinary Starship to orbit (and back) first!