Thanks for the updated capsule and Jupiter plan info.

I have always thought the 5m Orion capsule was oversized. It seemed to me that 4.5m was the largest size needed to accomplish the NASA requirements, and a capsule even smaller such as the old BAE study for a 4m ‘multi-role capsule’ could do the job.

But to followup on your two man lunar surface mission design, I still have some questions. If you are using a capsule which can carry a crew of four (whether it is a 5m or 4.5m capsule) why send only two crew? I thought the whole point of a two crew mission (as in the old Gemini direct scheme) was to use a small, lightweight two man capsule and thereby permit a much smaller launch vehicle.

What I don’t understand from my cursory scan of the Team Vision plan, is why their two-man lunar lander doesn’t take full advantage of the two-man mission size? The 7.1 tonne capsule for the two-man lunar crew is the same behemoth as the 8 tonne capsule for six-man ISS crew transfers. So a giant Jupiter II launch vehicle is needed with it’s 80 tonne TLI capacity to launch a two-man mission.

The ability to get there a lot sooner, cheaper, and probably at a lower cost per person by going with a two-man design seems to outweigh any benefits of doing a 4-person lander (at least as the first generation lander). You get a lot more flexibility by having two vehicles.

I don’t doubt that in the long run, the more people there at a base, the more you can get accomplished. I’m just dubious of the importance of all of them arriving on the same vehicle.

~Jon

That said, I think the first non-government trip may well be a stunt. While it may be possible to launch a single-man mission on a single Falcon IX S9 launch, I doubt it’s realistic. Falcon IX doesn’t exist yet period, and even if he does deliver it, he’s already stated that he’ll only do the S9 variant if someone pre-pays for the upgrades. Add to that the fact that a one-person mission isn’t safe, and that you’d have to be very agressive mass-wise to pull it off…

I think the first private lunar mission is going to be two-person. One pilot, and one passenger.

~Jon

Jon did leave the door open to 4 person teams on the moon, just not to 4-person LSAMs. That is where the real cost and architecture problems are. If you want 4 guys for a certain mission, put two 2-person crews on the ground. With the money you save from not developing the HLV (or the Stick, in a logical world) you could esily afford a two to one flight ratio to achive the same number of boots on the ground as the current plan. As Jon states, the incremental costs of the existing launchers should come down after boosting the flight rates.

Plus, you add flexibility for the missions and add a lifeboat emergency mode that gets an injured crew home without scrubbing the entire mission. You can stagger launch and arrival dates to have your site continuously occupied and make exploration more efficient with one crew briefing and teaching the next.

In addition, if you are in a higher rate production and launch mode, then sending cargo LSAMs to the site to deliver larger habitats, equipment, spares, vehicles and the like becomes much, much easier and cheaper. Apollo demonstrated that you could land within 300m of your desired point with no exterior landing aids. Imagine how close we could get them if an existing groundstation is providing a “fix” for the landing systems of the follow-on vehicles?

High flight rates are no longer normal at NASA and they may have reservations on doing them, but Gemini proved it could be done. 12 mission in 24 months with several being multiple launches of Geminis and Agenas. It can be done off the same pads if we think it through up front.

So, even if you decide you really have to have 4 people on-site to do a good job, the 2-man crew seems a much better vehicle size overall.

Paul

The engineering/business model moved us towards ELV’s as soon as it could because continuing to use an HLV for crew rotations would have consumed the entire budget leaving little money to build additional pieces. Any good architecture needs to provide at least 25% surplus at all times over operations to continue building incrementally pieces or it will stop dead in its tracks. Not chucking billion dollar LSAM’s is a good place to start.

We put up to four people on the Lunar Surface once we have Lunar habitats and six once we have the EML1 station up and running. Again not throwing away hardware is a good thing. Shoehorning four into a LSAM is not good thing either. It’s too small for a habitat and too big/$$$ to throw away after each mission.

The method of Lunar Surface Rendezvous (LSR) is superior way of increasing mission scope provided the crew component can return independently of the stage elements. Direct Ascent Architectures have a definite advantage in mass to surface.

Robot rovers will also have an important role exploring a vast area around the landing area and delivering return samples to the astronauts.

Four people on the Moon brings a lot of benefits that are not enumerated in your post.

The formost benefit is that there are more people to actually do work. If all NASA was going to do is a little bit of science, pick up rocks, and other things, then two people would be fine. However, if we want to really do ISRU, technology development, and actually build out a robust outpost, then you really need four people.

With a ~4380 hour crew rotation (6 months), and working the crew during daylight hours on outside task (illumination factor of 0.7 at the poles) you get a maximum number of work hours of ~5840 hours of crew time (4 crew x 8 hours per day). Also, with telepresence technology, the other time can be used productively by operating from the Earth.

This shifts the crew work from being the primary workers to support and construction crew. If ISRU is the focus, then there is a heck of a lot of Oxygen that can be processed. We need people on the Moon as much as we need machines.

Dennis