This past Friday's _PBS NewsHour_ had a piece about
NASA's Artemis project. They showed drawings of the
Lunar lander to be built by SpaceX and said it was a
modification of their Starship rocket:

https://www.nasa.gov/press-release/as-artemis-moves-forward-nasa-picks-spacex-to-land-next-americans-on-moon

I am surprised at the narrow footprint of the landing gear;
the vehicle is three times as high as it is wide. The Apollo Lunar
Module was wider than it was tall. The spread of the landing gear of
the Falcon boosters is about half the vehicle's height. SpaceX has
a good record now of recovering boosters but this is on a dedicated
landing pad, not on unprepared terrain (Lunain?), the boosters are
uncrewed, and a sufficiently low loss rate is acceptable.

The importance of stability in landing a spacecraft has been
considered several times in science fiction. In Robert Heinlein's
_Space Cadet_ and in Fred Hoyle's _Fifth Planet_ a tall, narrow
spacecraft lands and either falls over or tilts dangerously when
one landing jack hits a soft spot. In _The Soft Weapon_ Larry
Niven mentions that the human's ship has been designed for
landing ability (it has the proportions of a hockey puck) and
that the Kzinti ship is a compromise of atmospheric
performance and landing ability.

According to this article in Wikipedia, the SpaceX lander
has the provision for a system of auxiliary thrusters
mounted halfway up the fuselage with nozzles angled
downward. When the lander is near the Lunar surface
the main engines could be shut down and the final descent
and landing made on auxiliary thrust, avoiding the problem
of the main engines kicking up debris. This is similar to
the landing made in Heinlein's _Rocket Ship Galileo_:

https://en.wikipedia.org/wiki/Starship_HLS

Peter Wezeman
anti-social Darwinist

On Thursday, September 8, 2022 at 4:50:02 PM UTC-4, peterwezeman@hotmail.com wrote:
> This past Friday's _PBS NewsHour_ had a piece about
> NASA's Artemis project. They showed drawings of the
> Lunar lander to be built by SpaceX and said it was a
> modification of their Starship rocket:
>
> https://www.nasa.gov/press-release/as-artemis-moves-forward-nasa-picks-spacex-to-land-next-americans-on-moon
>
> I am surprised at the narrow footprint of the landing gear;
> the vehicle is three times as high as it is wide. The Apollo Lunar
> Module was wider than it was tall. The spread of the landing gear of
> the Falcon boosters is about half the vehicle's height. SpaceX has
> a good record now of recovering boosters but this is on a dedicated
> landing pad, not on unprepared terrain (Lunain?), the boosters are
> uncrewed, and a sufficiently low loss rate is acceptable.
>
> The importance of stability in landing a spacecraft has been
> considered several times in science fiction. In Robert Heinlein's
> _Space Cadet_ and in Fred Hoyle's _Fifth Planet_ a tall, narrow
> spacecraft lands and either falls over or tilts dangerously when
> one landing jack hits a soft spot. In _The Soft Weapon_ Larry
> Niven mentions that the human's ship has been designed for
> landing ability (it has the proportions of a hockey puck) and
> that the Kzinti ship is a compromise of atmospheric
> performance and landing ability.
>
> According to this article in Wikipedia, the SpaceX lander
> has the provision for a system of auxiliary thrusters
> mounted halfway up the fuselage with nozzles angled
> downward. When the lander is near the Lunar surface
> the main engines could be shut down and the final descent
> and landing made on auxiliary thrust, avoiding the problem
> of the main engines kicking up debris. This is similar to
> the landing made in Heinlein's _Rocket Ship Galileo_:
>
> https://en.wikipedia.org/wiki/Starship_HLS

I've been following the Starship for a long time, and it's
landing stability has bothered me a lot too. It has to find a level is h
spot, with consistent soil compaction.

A lot will depend on the weight distribution. We know that the engines,
which are heavy, are at the bottom. The empty spacecraft weights about
100t, but it supposed to be able to both land and return with a further
100t of cargo, which would make it top heavy.

Pt

In article <9cc5a662-69de-475a-8b48-f7c5f62007d2n@googlegroups.com>,
peterwezeman@hotmail.com <peterwezeman@hotmail.com> wrote:
>This past Friday's _PBS NewsHour_ had a piece about
>NASA's Artemis project. They showed drawings of the
>Lunar lander to be built by SpaceX and said it was a
>modification of their Starship rocket:
>
>https://www.nasa.gov/press-release/as-artemis-moves-forward-nasa-picks-spacex-to-land-next-americans-on-moon
>
>I am surprised at the narrow footprint of the landing gear;
>the vehicle is three times as high as it is wide. The Apollo Lunar
>Module was wider than it was tall. The spread of the landing gear of
>the Falcon boosters is about half the vehicle's height. SpaceX has
>a good record now of recovering boosters but this is on a dedicated
>landing pad, not on unprepared terrain (Lunain?), the boosters are
>uncrewed, and a sufficiently low loss rate is acceptable.
>
>The importance of stability in landing a spacecraft has been
>considered several times in science fiction. In Robert Heinlein's
>_Space Cadet_ and in Fred Hoyle's _Fifth Planet_ a tall, narrow
>spacecraft lands and either falls over or tilts dangerously when
>one landing jack hits a soft spot. In _The Soft Weapon_ Larry
>Niven mentions that the human's ship has been designed for
>landing ability (it has the proportions of a hockey puck) and
>that the Kzinti ship is a compromise of atmospheric
>performance and landing ability.
>
>According to this article in Wikipedia, the SpaceX lander
>has the provision for a system of auxiliary thrusters
>mounted halfway up the fuselage with nozzles angled
>downward. When the lander is near the Lunar surface
>the main engines could be shut down and the final descent
>and landing made on auxiliary thrust, avoiding the problem
>of the main engines kicking up debris. This is similar to
>the landing made in Heinlein's _Rocket Ship Galileo_:

(Hal Heydt)
In one of Niven's works, the bad guy has a ship with extra heavy
duty gryos. The protagonist rams it, jamming one of the three
landing legs, but the ship lands anyway, with the gyros keeping
it upright until shortly after the protagonist points out the
problem to the bad guy.

On Thursday, September 8, 2022 at 9:36:21 PM UTC-5, Dorothy J Heydt wrote:
> In article <9cc5a662-69de-475a...@googlegroups.com>,
> peterw...@hotmail.com <peterw...@hotmail.com> wrote:
> >This past Friday's _PBS NewsHour_ had a piece about
> >NASA's Artemis project. They showed drawings of the
> >Lunar lander to be built by SpaceX and said it was a
> >modification of their Starship rocket:
> >
> >https://www.nasa.gov/press-release/as-artemis-moves-forward-nasa-picks-spacex-to-land-next-americans-on-moon
> >
> >I am surprised at the narrow footprint of the landing gear;
> >the vehicle is three times as high as it is wide. The Apollo Lunar
> >Module was wider than it was tall. The spread of the landing gear of
> >the Falcon boosters is about half the vehicle's height. SpaceX has
> >a good record now of recovering boosters but this is on a dedicated
> >landing pad, not on unprepared terrain (Lunain?), the boosters are
> >uncrewed, and a sufficiently low loss rate is acceptable.
> >
> >The importance of stability in landing a spacecraft has been
> >considered several times in science fiction. In Robert Heinlein's
> >_Space Cadet_ and in Fred Hoyle's _Fifth Planet_ a tall, narrow
> >spacecraft lands and either falls over or tilts dangerously when
> >one landing jack hits a soft spot. In _The Soft Weapon_ Larry
> >Niven mentions that the human's ship has been designed for
> >landing ability (it has the proportions of a hockey puck) and
> >that the Kzinti ship is a compromise of atmospheric
> >performance and landing ability.
> >
> >According to this article in Wikipedia, the SpaceX lander
> >has the provision for a system of auxiliary thrusters
> >mounted halfway up the fuselage with nozzles angled
> >downward. When the lander is near the Lunar surface
> >the main engines could be shut down and the final descent
> >and landing made on auxiliary thrust, avoiding the problem
> >of the main engines kicking up debris. This is similar to
> >the landing made in Heinlein's _Rocket Ship Galileo_:
> (Hal Heydt)
> In one of Niven's works, the bad guy has a ship with extra heavy
> duty gyros. The protagonist rams it, jamming one of the three
> landing legs, but the ship lands anyway, with the gyros keeping
> it upright until shortly after the protagonist points out the
> problem to the bad guy.

I believe this was _Grendel_, one of the Beowulf Shaeffer stories.

Since the lander is intended to spend its entire working lifetime shuttling
from Lunar surface to Lunar orbit, if they decide to increase the landing
gear footprint they can do so with minimal mass penalty as the gear
would not need to extend or retract.

Peter Wezeman
anti-social Darwinist

On Thursday, September 8, 2022 at 11:25:10 PM UTC-4, peterwezeman@hotmail.com wrote:
> On Thursday, September 8, 2022 at 9:36:21 PM UTC-5, Dorothy J Heydt wrote:
> > In article <9cc5a662-69de-475a...@googlegroups.com>,
> > peterw...@hotmail.com <peterw...@hotmail.com> wrote:
> > >This past Friday's _PBS NewsHour_ had a piece about
> > >NASA's Artemis project. They showed drawings of the
> > >Lunar lander to be built by SpaceX and said it was a
> > >modification of their Starship rocket:
> > >
> > >https://www.nasa.gov/press-release/as-artemis-moves-forward-nasa-picks-spacex-to-land-next-americans-on-moon
> > >
> > >I am surprised at the narrow footprint of the landing gear;
> > >the vehicle is three times as high as it is wide. The Apollo Lunar
> > >Module was wider than it was tall. The spread of the landing gear of
> > >the Falcon boosters is about half the vehicle's height. SpaceX has
> > >a good record now of recovering boosters but this is on a dedicated
> > >landing pad, not on unprepared terrain (Lunain?), the boosters are
> > >uncrewed, and a sufficiently low loss rate is acceptable.
> > >
> > >The importance of stability in landing a spacecraft has been
> > >considered several times in science fiction. In Robert Heinlein's
> > >_Space Cadet_ and in Fred Hoyle's _Fifth Planet_ a tall, narrow
> > >spacecraft lands and either falls over or tilts dangerously when
> > >one landing jack hits a soft spot. In _The Soft Weapon_ Larry
> > >Niven mentions that the human's ship has been designed for
> > >landing ability (it has the proportions of a hockey puck) and
> > >that the Kzinti ship is a compromise of atmospheric
> > >performance and landing ability.
> > >
> > >According to this article in Wikipedia, the SpaceX lander
> > >has the provision for a system of auxiliary thrusters
> > >mounted halfway up the fuselage with nozzles angled
> > >downward. When the lander is near the Lunar surface
> > >the main engines could be shut down and the final descent
> > >and landing made on auxiliary thrust, avoiding the problem
> > >of the main engines kicking up debris. This is similar to
> > >the landing made in Heinlein's _Rocket Ship Galileo_:
> > (Hal Heydt)
> > In one of Niven's works, the bad guy has a ship with extra heavy
> > duty gyros. The protagonist rams it, jamming one of the three
> > landing legs, but the ship lands anyway, with the gyros keeping
> > it upright until shortly after the protagonist points out the
> > problem to the bad guy.
> I believe this was _Grendel_, one of the Beowulf Shaeffer stories.
>
> Since the lander is intended to spend its entire working lifetime shuttling
> from Lunar surface to Lunar orbit, if they decide to increase the landing
> gear footprint they can do so with minimal mass penalty as the gear
> would not need to extend or retract.

The proposed lander variant also skips the tiled heat shield and the
flaps.

Pt

On Thursday, September 8, 2022 at 11:25:10 PM UTC-4, peterwezeman@hotmail.com wrote:
> On Thursday, September 8, 2022 at 9:36:21 PM UTC-5, Dorothy J Heydt wrote:
> > In article <9cc5a662-69de-475a...@googlegroups.com>,
> > peterw...@hotmail.com <peterw...@hotmail.com> wrote:
> > >This past Friday's _PBS NewsHour_ had a piece about
> > >NASA's Artemis project. They showed drawings of the
> > >Lunar lander to be built by SpaceX and said it was a
> > >modification of their Starship rocket:
> > >
> > >https://www.nasa.gov/press-release/as-artemis-moves-forward-nasa-picks-spacex-to-land-next-americans-on-moon
> > >
> > >I am surprised at the narrow footprint of the landing gear;
> > >the vehicle is three times as high as it is wide. The Apollo Lunar
> > >Module was wider than it was tall. The spread of the landing gear of
> > >the Falcon boosters is about half the vehicle's height. SpaceX has
> > >a good record now of recovering boosters but this is on a dedicated
> > >landing pad, not on unprepared terrain (Lunain?), the boosters are
> > >uncrewed, and a sufficiently low loss rate is acceptable.
> > >
> > >The importance of stability in landing a spacecraft has been
> > >considered several times in science fiction. In Robert Heinlein's
> > >_Space Cadet_ and in Fred Hoyle's _Fifth Planet_ a tall, narrow
> > >spacecraft lands and either falls over or tilts dangerously when
> > >one landing jack hits a soft spot. In _The Soft Weapon_ Larry
> > >Niven mentions that the human's ship has been designed for
> > >landing ability (it has the proportions of a hockey puck) and
> > >that the Kzinti ship is a compromise of atmospheric
> > >performance and landing ability.
> > >
> > >According to this article in Wikipedia, the SpaceX lander
> > >has the provision for a system of auxiliary thrusters
> > >mounted halfway up the fuselage with nozzles angled
> > >downward. When the lander is near the Lunar surface
> > >the main engines could be shut down and the final descent
> > >and landing made on auxiliary thrust, avoiding the problem
> > >of the main engines kicking up debris. This is similar to
> > >the landing made in Heinlein's _Rocket Ship Galileo_:
> > (Hal Heydt)
> > In one of Niven's works, the bad guy has a ship with extra heavy
> > duty gyros. The protagonist rams it, jamming one of the three
> > landing legs, but the ship lands anyway, with the gyros keeping
> > it upright until shortly after the protagonist points out the
> > problem to the bad guy.
> I believe this was _Grendel_, one of the Beowulf Shaeffer stories.
>
> Since the lander is intended to spend its entire working lifetime shuttling
> from Lunar surface to Lunar orbit, if they decide to increase the landing
> gear footprint they can do so with minimal mass penalty as the gear
> would not need to extend or retract.
>
> Peter Wezeman
> anti-social Darwinist

A detAiled description of Artemis may be found here:
https://ntrs.nasa.gov/api/citations/20220013431/downloads/HLS%20IAC_Final.pdf

Pt

On Fri, 09 Sep 2022 12:08:37 -0700, pete...@gmail.com wrote:

> On Thursday, September 8, 2022 at 11:25:10 PM UTC-4,
> peterwezeman@hotmail.com wrote:
>
> A detAiled description of Artemis may be found here:
> https://ntrs.nasa.gov/api/citations/20220013431/downloads/HLS%
20IAC_Final.pdf
>
> Pt

You call that detailed? I haven't been following space news
closely. If they're about to launch a rocket that carries this
thing hasn't a prototype already been built? There should be lots
of pictures of it somewhere.