Comparison of Blue Moon, Starship HLS and Apollo LEM.

https://cimg4.ibsrv.net/gimg/pprune....a767eda8a5.png

Obviously, greater intelligence than my feeble brain is inventing this stuff, but we see three actual/potential landers standing upright on an unprepared, lunar, brownfield site.

Am I alone in looking at the height-to-base relationship of Starship's perceived CofG, then comparing it to the Apollo LEM, and feeling a certain unease?

It would be reasonably easy to put a 'self leveling' system on the landing gear to insure that - after landing - the Starship is (and remains) perfectly vertical. Heck, at least on this side of the pond, large motorhome type vehicles have such a system.
Remember, the LEM was done in a very minimalistic fashion - both due to technology of the day and the need to absolutely minimize the vehicle weight (the drive to minimize the LEM weight was why the astronauts stood during descent and landing - not only did it get rid of the weight of the chairs, it allowed the (heavy) windows to be much smaller while allowing the needed field of view while landing.

When the LEM was designed nobody knew the composition of the moon’s surface - it was feared it would be a thick layer of dust in which the feet could sink.

Sink the Apollo missions it is known it is a hard surface and, by choosing the appropriate landing sites, the risk of toppling is insignificant.

Even cold gas thrusters on the nose will have a lot of say in if the thing stays upright once it's engines off. Long moment arm there.

It would be interesting to hear how they've assessed the hazard from rock debris flying around under the ship during landing.

NASA has been working on that for years.

https://www.nasa.gov/centers-and-fac...g%20visibility.

https://www.nasa.gov/general/rocket-exhaust-on-the-moon-nasa-supercomputers-reveal-surface-effects/

https://phys.org/news/2024-03-lunar-missions-moondust.html

https://ntrs.nasa.gov/api/citations/...dings%20v1.pdf

A Just for info - I forget when the LM gear design was frozen but as I recall it the dust theory was never really a major consideration or a driver for the LM gear design or spec..that was a pet theory amongst certain astronomers, Thomas Gold almost made a career out of it…and of course the media picked up on it

Coping with landing on a sea of very thick fine dust ended up not being a major consideration in the way gear design evolved, especially after the first close up, fine detail pictures of the surface started coming back came back from ‘64 onwards.

The two main drivers behind the final gear configuration were concern about surface gradients (knowledge of which was poor at the time) and/or toppling due to excessive horizontal velocity on touchdown…two things that I suspect will still be of concern to some extent and I’m sure will have been factored into the design of the HLS and subsystems.

SpaceX: Flight 6 November 18 - (now an update on the SpaceX site).

4 pm Local window opening. Allows for Ship flip and burning landing in daylight.

Raptor relight added as an objective, along with TPS and other test objectives!

Oh, and a Mechazailla booster catch again, of course!

https://www.spacex.com/launches/miss...rship-flight-6

…..Starship’s upper stage will fly the same suborbital trajectory as the previous flight test, with splashdown targeted in the Indian Ocean. An additional objective for this flight will be attempting an in-space burn using a single Raptor engine, further demonstrating the capabilities required to conduct a ship deorbit burn prior to orbital missions.

Several thermal protection experiments and operational changes will test the limits of Starship’s capabilities and generate flight data to inform plans for ship catch and reuse. The flight test will assess new secondary thermal protection materials and will have entire sections of heat shield tiles removed on either side of the ship in locations being studied for catch-enabling hardware on future vehicles. The ship also will intentionally fly at a higher angle of attack in the final phase of descent, purposefully stressing the limits of flap control to gain data on future landing profiles. Finally, adjusting the flight’s launch window to the late afternoon at Starbase will enable the ship to reenter over the Indian Ocean in daylight, providing better conditions for visual observations.

Future ships, starting with the vehicle planned for seventh flight test, will fly with significant upgrades including redesigned forward flaps, larger propellant tanks, and the latest generation tiles and secondary thermal protection layers as we continue to iterate towards a fully reusable heat shield. Learnings from this and subsequent flight tests will continue to make the entire Starship system more reliable as we close in on full and rapid reusability.

Apollo 16 missed a huge crater by sheer luck. John Young and Charlie Duke flew over a rather large crater which was obscured by exhaust blown dust, landing just beyond it. The first they knew of the crater was on the moonwalk where they wandered around to the rear of the vehicle. Had they put down slightly earlier then it could have ended badly. The boulder field encountered by Apollo 11 was a bit of a surprise, partly due to Aldrin inadvertently overloading the guidance computer that stretched their landing. I'm not sure that Nasa either knew of or anticipated its existence. There was some knowledge of soil mechanics thanks to the surveyor missions which were equipped with scoops and cameras, not to mention images of the lander pads on the lunar soil. The distribution and depth on a wider scale was still an unknown.

Full automation also has issues, not least of which was a recent US robotic lander where the radio altimeter went off the scale due to crossing a crater. The system judged that the sensor was faulty and locked it out with unfortunate results.

The next manned landers have a difficult choice in landing somewhere safe but bland, or more challenging and interesting.

Sounds like they're going to push it hard - wouldn't be surprised if this one doesn't make it to a controlled landing!

That’s about one launch every 2 weeks….

I agree. This sort of destructive testing may seem wasteful to some but they need to get as much data as possible to finalise the design. Especially the heat shield.

Indeed. I think this is the last of the Block #1s that'll fly, so stressing the common components between that and V2 would be a sensible use of the flight for sure.

Still a stockpile of Raptor 2s to use up before we see Raptor 3s being used.

Starship 33 Raptor engines are being installed today. Both Sea Level and Vacuum variants. This is the first Next gen design Starship and is expected to fly on flight 7.

11/9/24

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Starship 31 has rolled out of the high bay today preparing for upcoming test flight 6 in T-minus 7 days.

11/11/24

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Booster 13 has rolled out of Megabay 1 today and is expected to rollout to the launch complex overnight for upcoming Starship test flight 6 at T-minus 5 days and counting!

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Booster 13 lifted onto the launch mount at sunrise today at T-minus 4 days and counting!

11/14/24



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I'm sad that pretty soon this'll be routine. I remember watching every F9 landing and got a bit emotional when Heavy launched the first time, but now I barely notice them :/

"Progress", I guess.