New Mars Forums

Official discussion forum of The Mars Society plus Red Planet Bound [BLOG] With Newmars lifeBoat a communications backup plus New Mars Image Server

You are not logged in.

Topics: Active | Unanswered

Announcement

Announcement: This forum is accepting new registrations via email. Please see Recruiting Topic for additional information. Write newmarsmember[at_symbol]gmail.com.

Pages: 1

#1 2026-06-04 17:26:29

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 25,078

Hop Postings

Hop last added a post to this forum in 2014. It is good to see you back, and hope you'll have time to help us rebuild the forum.

We've been through a number of difficult periods while you've been away.

The count of users stands at 19,000+ because a swarm of hackers added fake users before SpaceNut put a stop to it.

Rather than delete all those fake ID's, we converted them for use by new (real) people members.

However, the going has been slow. We've added five or six folks, and a couple made serious contributions before they too went away.

This topic is available for personal communication with you, or for you to drop off posts if no existing topic quite fits.

Your post about a zero energy transfer orbit for Deimos and Phobos is sure to be of interest to GW Johnson.

We have a course on ellipses set up ... look for topics with "original" in the title.

I noticed your coloring book for youngsters interested in orbital mechanics.

We've had some outages. We set up a lifeboat in case we ever go down again.

SpaceNut created links on the main page. The image server is running but not linked to the data base.

That's a little detail left over from the most recent hacker-caused outage.

(th)

Offline

Like button can go here

#2 2026-06-06 11:52:12

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 25,078

Re: Hop Postings

For Hop re Tethers topic...

GW Johnson has chosen to engage with you.

I'm hoping you are in good health, and that you have the time and energy to reply.

GW has reminded us all of the perennial omission from posts about topics: Angular Momentum.

However, there ** is ** one case in which angular momentum need not be given to an object. That one case is the "straight out" scenario.

I am hoping you might be able to show that your vision of two orbiting bodies passing mass back and forth would work with the "straight out" scenario working from both ends.

In the "straight out" scenario, a mass is projected from the launching mass with a modest momentum toward a meeting point. The mass is held by a very light weight line that is not intended to sustain much tension.

At the same time, a mass is projected from another launching mass with a modest momentum toward a meeting point. This mass is also held by a very light weight line that is not intended to sustain much tension.

If I understand your post correctly, in the Mars case, there exists a meeting place where Phobos and Deimos could exchange masses. Upon exchange, each moon would draw the exchanged mass back into the launching body.

GW Johnson has asked why anyone would do this, and this post is not intended to try to answer the question. However, if there were someone who really wanted a reason, then the exchange of personnel would be a reason.

GW Johnson has also asked the perfectly sensible question ... why not just use rockets?

I think that question makes sense if we assume a rocket transportation system infrastructure and all the energy needed to sustain such an infrastructure. It seems to me the tether exchange system you have imagined would operate with very little energy. You would need sufficient energy to launch your two masses from the respective bodies, and you would need energy to draw the lines back in after the exchange.

The tether system would not require the advanced navigational computing systems that would be required for safe operation of GW Johnson's orbital transfer service. However, the tether system ** would ** require advanced computer based navigational computing systems that deal with the unique scenario I think you are proposing.

(th)

Offline

Like button can go here

#3 2026-06-07 20:06:01

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 25,078

Re: Hop Postings

For Hop re Tethers post ...

Thank you (again) for providing your discovery of an interesting orbit in the Mars system.

At today's Google Meeting, GW Johnson spent some time thinking about your presentation. In the same meeting we reviewed his latest paper on delivering mass between Phobos, Deimos, Mars and Low Mars Orbit using rockets.

I have reported a conversation with a lightweight AI (Google Search) about your discovery. I regret the conversation is not nicely formatted, but the bottom line is that the Phobos leg requires the use of a rocket to lift a package to the perigee of the orbit you found. Once the rocket has reached the perigee and imparted the required velocity to the package, then the package will indeed coast up to Deimos' package collector at the end of a tether. It would be interesting to see how much energy is required for the entire transaction.

GW Johnson has computed all the energy requirements for all phases of the requested package delivery service. It would be interesting to see if there is any advantage to use the tether dropped from Deimos to save energy. Naturally, a tether cannot be dropped ** up ** from Phobos, so that phase of the mass transfer has to be performed by a rocket.

(th)

Offline

Like button can go here

#4 2026-06-07 21:08:13

tahanson43206: Moderator; Registered: 2018-04-27; Posts: 25,078

Re: Hop Postings

Update for Hop ....

I've invited GW Johnson to take a look at a scenario that might work for your discovered orbit.

The ** secret ** is to drop the tether down to Phobos from a transfer hub in your discovered orbit.

If we used electricity to lift packages up to Deimos from the bottom of it's 3000 km tether, and if we used electricity to lift packages from Phobos to the transfer hub, then the entire transaction could be carried out with electricity and no mass would be expended at all.

I've asked GW Johnson to investigate to see if this scenario is plausible.

For you I have a follow up question. How often would the orbit be usable? If the orbital alignments are only good once a century, the orbit you found is not very useful.

In any case, thanks for providing such an interesting idea for study.

(th)

Offline

Like button can go here