doublehelix":2dy7zizq said:
Congress gave NASA the OK to shift focus from sending astronauts back to the moon by 2020 and instead aim for an asteroid by 2025 and then Mars by 2030. You like? Vote in our poll and tell us what you're thinking.
I voted Big mistake bypassing the moon. However I don't see it as a launching point for other destinations, nor as practice for other destinations.
There are likely
massive ice deposits at the poles. Chandrayaan-1 and LRO have detected what seem to be
sheets of relatively pure ice at least two meters thick. Water can be used for drinking, radiation shielding, a source of oxygen to breath, and a source of hydrogen and oxygen for propellent.
This propellent is much closer to LEO and EML1 than earth. Using aerobraking, lunar propellent is about 3 km/sec from LEO. Lunar propellent could be delivered to LEO with reusable vehicles, earthly propellent must be delivered to LEO with disposable rockets.
Launching for Mars or NEOs from the moon would take more delta V than launching from LEO. So the moon would
not be a launching point for other destinations. This is often used as an erroneous argument against using lunar propellent. Lunar supplied propellent depots at LEO and EML1 would be the launching points for other destinations.
An upper stage with empty propellent tanks would be a much less massive payload to LEO. At LEO it can use lunar propellent to get to EML1 where it can refuel again. From EML1 it has a 2.4 km/sec advantage over LEO. Lunar supplied propellent depots would be a major game changer for reaching Mars, NEOs or
any deep space destination in our solar system.
The ice sheets at the poles are likely layers that have accumulated over billions of years. This could be a record of our solar system's history just as the fossils in sedimentary rock are a record of life's history on earth. So far as scientific interest goes, the moon is a better destination that Mars or NEOs.
Further, launch windows to the moon open every two weeks, trip time is a few days. Launch windows open every two years for Mars and every few decades for a given NEO. Trip times to Mars or NEOs would be months to years. Building infrastructure on the moon is doable. Rarity of launch windows and long trip times make building permanent martian or NEO bases much more difficult. Given $19 billion a year, I see it as flags and footprints sortie missions vs building a permanent base.
I like the Senate bill in that it at least throws a few scraps to commercial space. Although a high flight rate would be very helpful in getting commercial space off the ground. Rare Martian or NEO launch windows can't offer the flight rate lunar development could.
The senate seems to be ditching Ares I - V which I like. Although a HLV SLS would not be necessary for lunar missions. With the
ULA architecture, Atlas Vs and propellent depots do the job.