New Mars Forums

I wasn't referring to the Habitat module as a throwaway, simply the ultralight lunar landers. I'm willing to bet the cost of development from Northrup-Grumman would exceed $250 Million! Using existing and future useful hardware could keep the entire program under a half Billion.

The other problem: we don't HAVE a Mars habitat module, either.

One would really need it due to the 14 day diurnal cycle, during the "dark phase." Staying on the Moon for  long period of darkness is one of the reasons for NOT going there. "A neat place to visit, but I wouldn't want to live there."

IMHO, we've equipment-wise progressed beyond the "minimalist approach' taken by the 1960s NASA design teams, and thus, should be utilizing some of the more sophisticated hardware becoming available. I'd be all for reverse engineering the landing, and subsequent Earth return of a Red Dragon vehicle from the lunar surface. It would require orbital assembly techniques unavailable to the Apollo mission designers. Working backwards, we need a lunar departure booster based on the current Dragon trunk unit, powered by MMH/NTO unit capable of getting the necessary delta-V for lunar departure and trans-Earth trajectory. The Red Dragon capsule should be slightly uprated w/r fuel on board to permit midcourse corrections and Earth touchdown requirements. Call that portion 8 metric tons. The trunk departure stage would be scaled to doing the boost into ERT, leaving on the lunar surface the landing stage with legs, descent engines, etc. The lunar landing stage should be scaled to complete insertion into lunar orbit, and a subsequent landing. Prior to that, there will be another stage constructed to accomplish the trans lunar trajectory, which COULD accompany the Dragon, retaining enough fuel for  final destructive boost into a solar trajectory, but also capable of becoming the experimental tether system counterweight; thereby allowing artificial gravity experiments to be conducted for say 3 days? All these various booster stages could be chunks of appropriately engined hardware based on expansion of the Dragon cargo trunk currently used as an unpressurized cargo up to the ISS.

Maybe GW could do these back calculations; it's been too long since I did this sort of stuff as an aerospace undergrad some 55 years ago. But--this would get us away from the "flimsy landers" with limited accommodations for the crew. Yeah, we can bring back more rocks....if only for evidence that we've returned to the moon. In and of itself, the lunar return is nothing more than an exercise demonstrating that we still are capable of leading the way to the stars. It can also serve as a technology demonstration for the Red Dragon capsule and also demonstrate the tether for artificial gravity production. The moon rocks are just more dead weight on the return.

Take a look at my post #56 on the SpaceX, NASA, and the New Administration thread; the utilization and/or modification of existing or already proposed hardware should be combinable into a Moon vehicle system.

Proposed architecture: Dragon 2 capsule initially modified for an Apollo 8 redux with increased food and consumables simply by lengthening the capsule. Convert the trunk segment into a booster stage with enough fuel to undertake Moon orbit insertion and orbital departure on a return trajectory. Have an in-orbit assembly of an Earth orbit to lunar trajectory throwaway booster. Could in principle, become a technology demonstrator for the tether system of artificial gravity production? This system could utilize the surplus crew capacity of 7, scaled back to 2-3-4 astronauts in order to conserve oxygen and consumables.

For the Apollo 11 redux, lengthen the trunk stage(s) to include a lunar landing motor, fuel supply for landing in a separable stage that could be left behind with landing legs, etc. The other trunk stage would contain a motor and fuel for lunar departure. The Dragon capsule would have the 8 small Raptor engines and MMH/NTO fuel for an Earth landing. This whole system is again, built at the ISS, thereby making the boys at NASA's eyes cross with ecstasy. This only tasks SpaceX with building the intermediate stages modified from the currently unpressurized cargo trunk.This whole system isn't some multi-billion dollar wet dream. Just a rationalization of existing capabilities.

When earlier I spoke about lifetimes, I meant the lifetimes of the astronauts. No one would really want to spend 3 years going to a destination, then stay a while to do science, and return for another 3 years. That's just too big a chunk of the normal human lifetime to invest on a project.

Some of the information presented here regarding gas phase nuclear propulsion could cut a mission time span to a total of 5-6 years to Callisto and the 2 major asteroids, Vesta and Ceres. Beyond Jupiter is going to require a more advanced propulsion system. I don't anticipate using light sails and lasers, or electromagnetic propulsion to do so, simply due to the enthalpy requirements. Zubrin points that out in "Entering Space." The next step outward will require thermonuclear propulsion, which could also lead to interstellar travel.

Chemical propulsion as some have pointed out, can get us to Mars and the asteroids as well as back to the Moon. Beyond that--requires an entirely new paradigm.

The only way I see getting to the outer solar system reasonably is through use of Nuclear Thermal units, especially the gas phase ones described by Robert.

Robert-

It would seem to me the Moon would make a great place for a Gas Core test site! No atmosphere; no one else around to complain! I suspect that chemical propulsion will be around for a long time, just getting any space vehicles out of the atmosphere. This is just about the only reason I could support (other than military/strategic bases) for lunar development.

But--the "how do we get there" definitely precedes in thinking of "where do we go next."

It would really be an Object Lesson for NASA; what can be accomplished when there is a defined objective and the political will to accomplish same...

The ULA Delta IV Heavy doesn't have the capability to launch enough into LEO, leaving the upcoming Falcon Heavy as the "only game in town," for accomplishing ANYTHING in the near term. Why has Trump met with Elon Musk 3 times since the inauguration?

After re-reading the words of the master, he comes to a conclusion of a 25 metric ton system landing on the Red Planet. Based on a 180 day manned flight, which requires a delta V of 5.08 km/second from LEO. Zubrin makes a great case for the 4 man mission, especially in the early pioneering flights. My reasoning for a larger crew/larger ship and a second ship is based on what needs to be accomplished versus the eventual physical and mental exhaustion of the individuals involved in this enterprise. Yes, it's possible for a solo mission, a 2 man, or 4 man crew to "do" the mission, but they would be in pretty bad shape by the end of it, both physically AND mentally/emotionally..

Of course, my mission architecture includes prepositioned nuclear reactor, food, equipment, water and vehicle caches. In addition to components for erecting a habitat--a Bigelow version of a Yurt, need be. The ISPP plant should be producing both components of the methylox fuel-oxidizer couple for the prepositioned ERV.

My bottom line: If we are going to Mars, go there in sufficient force to show that we're there TO STAY. My second words of wisdom: remember that Murphy was an optimist.

My mission architecture is based on an upgrade to a 5 meter diameter Dragon 2+, or a Dragon 3--whatever. That and building components that would be mission specific. Still using the Falcon Heavy and Falcon Block 5 for ferrying loads to orbit.

There are too many variables involved regards the weight actually launched to Mars. What transit time is acceptable, how many crew, how much and what equipment, etc. Then there's always the estimates of dry weight w/o propellants to consider. I just ran a few weight estimates for an upgraded Dragon 2 spacecraft, crewed at the max with 7 crew, supplies, O2, H2O, propellants, landing stage, etc, at roughly 92,000 kg. This is the mass that would be launched into trans-Mars flight. That should allow the engineers among us to come up with (1) thrust required, (2) delta V, and finally, (3) how much fuel needed to accomplish such. In my model, I have a fuel allowance of ~ 42,000 kg of MMH and NTO. A "landed weight" is thereby ~ 50,000 kg. My fuel allowance is just a WAG. So--maybe need a little more or maybe a whole lot less? This is the fuel onboard the Mars landing vehicle, not that needed for TMI.

Here's what I know about Nuclear Thermal Rockets and the NERVA Project.

https://youtu.be/VyGKMF7qIGw