Problem Soft touchdown on Phobos ?

[Stebb]

Has anyone tried landing the Delta glider on Phobos or Deimos using Orbiter 2024 rc1 or rc2 ?

I have found two problems which prevents successful landing:
Either (1) The vessel sinks below the surface with no solid ground to be found at any depth underground. This also causes the frame rate to seriously drop.
Or (2) During landing approach while descending at around 0.5m per second, at an altitude of about 20m the DG receives an upward kick on the nose wheel which sends it into a nose over tail rotation and a resultant vertical velocity in the upwards direction of around 6m per second.

I don't know why either one or the other happens but it means my two favourite little moons are no-go zones.

 

[francisdrake]

Well, you can visit the Phobos-Monolith with the Janus Expedition in Orbiter 2016.
The spacecraft is a re-purposed Lunar Gateway. It lands on its belly and is stabilized by the solar wings.
I am not sure how it behaves in Orbiter 2024, but would be interested in a test flight.

 

[n72.75]

Has anyone tried landing the Delta glider on Phobos or Deimos using Orbiter 2024 rc1 or rc2 ?

I have found two problems which prevents successful landing:
Either (1) The vessel sinks below the surface with no solid ground to be found at any depth underground. This also causes the frame rate to seriously drop.
Or (2) During landing approach while descending at around 0.5m per second, at an altitude of about 20m the DG receives an upward kick on the nose wheel which sends it into a nose over tail rotation and a resultant vertical velocity in the upwards direction of around 6m per second.

I don't know why either one or the other happens but it means my two favourite little moons are no-go zones.

was this in 64 bit OO? if so, try it in 32 bit

Thread '64 Bit Orbiter Builds are Not Currently Useable'

Sep 13, 2024

This is a known problem. I am making this post here (hopefully we can sticky it), as both a notice, and someplace we can link people to when they run across this issue. For developers: the issue and the fix are known, so hopefully this saves someone a few hours of troubleshooting.

64 bit Builds of Orbiter are not currently usable (out of the box at least). In general if you want to try out the latest release of OpenOrbiter, stick with the 32bit x86version. If you're a bit more experienced and or working on development/experimentation: as you were.

The reason for the issue:

The moons of...

• n72.75
• Replies: 2
• Forum: Orbiter Development

• 

 

[GLS]

was this in 64 bit OO?

I tried x86 and a DG went thru the surface, kept going down and then went thru the mean radius circle (or whatever is displayed in OrbitMFD). Eventually it shot up and was ejected.
It probably is a result of those moons being small, thus low gravity and Mars still dominates (at least it is indicated as such in OrbitMFD), and that might mess up the touchdown logic and so the vessel continues down...

 

[Stebb]

I think the full 2024 rc2 and rc2 download packages from GitHub are the x86 version. Anyway, I have used both with the same result, i.e. not being able to touchdown on the moons of Mars.

However with Orbiter 2016 the surfaces of both Phobos and Deimos are solid which allows for beautiful gentle touchdowns. Touchdowns need to be really gentle especially if approaching on a slant because the gravity is sooo tiny.

Looking forward, in the fullness of time to being able to touchdown on these moons in Orbiter 2024 too.

 

[Boxx]

However with Orbiter 2016 the surfaces of both Phobos and Deimos are solid which allows for beautiful gentle touchdowns. Touchdowns need to be really gentle especially if approaching on a slant because the gravity is sooo tiny.

That's true. Nevertheless, with OMP/OMX I experienced this nose over tail rotation because of a bad interpretation of "elevations" (which must be reconstructed in the multi-user approach...). Orbiter was assuming a perfect sphere, i.e. a surface well above the terrain.
Maybe OO 2024 has the same issue.
As well, the "reference body" keeps being Mars because of the low gravity of Phobos, which also added to the mess in interpreting the elevations.