On Saturday, March 26, 2016 at 6:02:54 AM UTC+13, wrote:
"The European Space Agency recently announced plans for an international moon
base. The agency believes they could start building the complex in 20 years, with
different countries focusing on their areas of expertise."

See:

http://www.techinsider.io/esa-intern...-agency-2016-3

More here;

http://www.space.com/29285-moon-base...ce-agency.html

Yes, ESA is following my advice, which originated 20 years ago, and is documented here;

http://www.asi.org/adb/02/06/inflatables-study-1.html

Consider the following hypergolic propellants: NTO/MMH used in rockets that have up to 2.9 km/sec exhaust speed. In combination this propellant has a combined density of 1.2 kg/litre (1.2 metric ton per cubic meter).

So, a Dragon Capsule with a solar powered trunk, massing 6 tons at lift off, must achieve 2.95 km/sec delta vee to boost to a lunar free return trajectory, that takes a vehicle to the moon in four days, and then imparts 2.30 km/sec delta vee to slow to a lunar landing from trans-lunar orbit, and then impart another 2.30 km/sec delta vee to blast back to Earth.

So, starting on the moon return and working backwards;


u = 1 - 1/exp(2.30/2.90) = 0.547562 -- p=1-u = 0.452438 -- TOW=P/p = 6000/0.452438 = 13,261.5
U = u * TOW = 7,261.5 kg - propellant -- 6,051.2 litres -- 2260..9 mm diameter

We find that to get the Dragon capsule and trunk back to Earth from the surface of the moon requires that 54.7562% of the take off weight must be propellant. Which for a 6,000 kg Dragon capsule & trunk means 7,261.5 kg of NTO/MMH propellant must be carried along - which will fid into 2.26 m diameter spherical tank, with a bulkhead dividing it into appropriate ratios. The weight of the tank is 315 kg.

A similar calculation would take this combined total and land it softly on the moon, after arriving at the lunar vicinity. This requires; 13,261.5 / 0.45238 = 29,311.1 kg -- 16,049.63 kg of additional propellant. This is a pill shaped tank, with spherical end caps, that's 4,085.1 mm long and 2,260.9 mm diameter. The weight of this tank is 698 kg.

The combined mass of the two tanks Dragon capsule with trunk, is 30,324.1 kg in LEO.

The Falcoln heavy has the capacity to accelerate 16,600 kg into a translunar trajectory using LOX/RP1 Merlin vacuum engine attached to the Falcon upper stage. The Merlin Vaccum engine has a 3.4 kg/sec an Isp of 345 seconds achieved with an expansion ratio of 117:1. For added reliability of restart, the engine has dual redundant pyrophoric igniters (TEA-TEB). This has an exhaust speed of 3.4 km/sec.

http://www.spacex.com/falcon-heavy

So, two launches of the Falcon heavy, one with the Dragon capsule and lunar return tank, totalling 13,261 kg and a second booster carrying the larger NTO/MMH propellant tanks totalling 16,100 kg. Both feed the Super Draco engines are capable of landing on the moon and returning to Earth, once supplied with propellant.

https://www.youtube.com/watch?v=2c4Wvgn9_CU
https://www.youtube.com/watch?v=5bhW2h08zhY

So, two Falcon heavy rockets launch payloads on a trans lunar trajectory. The capsule and trunk with smaller propelant tank attached to the nose and a second payload consisting of larger pill shaped tank. The capsule docks with the larger propellant tank while on its way to the moon and both payloads land on the moon using the capsule's super Draco engines. The depleted tank is left on the moon. The larger tank is opened to vacuum, to cleanse it of propellant residue, sealed back up, and attached to a life support unit in the trunk, for use as a pressure vessel for lunar housing.

An un-piloted Dragon capsule - a cargo version - sent to the moon - leaves a modified solar powered trunk there along with a 2.26 m diameter and 4.08 m long pressure vessel which serves as a base and carries up to 3 tons of supplies. The capsule and smaller tank return to Earth for recovery and reuse. In a manned flight the capsule and trunk are returned with the astronauts and smaller tank. The larger tank is added to the 'lunar trunk' - which accepts up to six tanks connected radially to the central trunk. This trunk houses not only solar panels but also supplies and a series of connectors and airlocks.

So, with two launches, at $90 million each, and seven people, that's $25.72 million per person to land on the moon and return to Earth. Sending 84 people to the moon, at a rate of 7 per month, requires 24 launches per year earning $2.16 billion.

The USA is paying $70 million to send an astronaut to the International Space Station. $75 million to send people to the moon for two weeks, seems like a good deal.

Extracting the Super Draco engine array from the Dragon Capsule, to create a "Lunar Light" version of the system described above, for a one way journey, with no propellant, would allow 12,000 kg to be placed on the lunar surface. This is a little over half the size of the BA-330. So, an expanded hotel would be possible using inflatable technologies.

The Chinese and Indian rovers and orbiters report vastly more ice and water on the moon than reported by the USA in the past. Most of this appears to be around the lunar polar regions. A pair of 16,000 kg payloads totalling a single 32,000 kg payload after docking, when slowed by hydrogen oxygen propellant combination that is replenished on the moon from water supplies found there, requires;

u = 1 - 1 /exp(2.3/4.6) = 0.393469, p = 1 - 0.393469 = 0.606531

32000 * 0.393469 = 12,591.0 kg -- 4,096 mm diameter sphere 544 kg.

32,000 - 12,591 - 544 = 18,865 kg.


Part A: 16,000 kg - inert
Part B: 2,865 kg - inert, 544 kg tank, 12,591 kg propellant.

This supplies 6x the payload to the moon than the SpaceX derived system, using the same launchers. Looking at the 7 people that are supported by a 3,000 kg Dragon capsule, 16,000 kg will likely support the transport of 35 to 42 people. With reusable hardware, launch costs are reduced to $40 million per pair, so, this drops to the $1 million to $1.5 million range in costs, and $4 to $5 million in costs. At these prices numbers per year rise from 84 per year spending 2 weeks each on the moon, to 2,000 per year, spending several months on the moon. Population rises from 7 on the moon, part of the month, to 100 on the moon permanently. Launch rates rise from two per month to six per month. Revenues rise from $2 billion per year to $12 billion per year.

This sets the stage for Mars.