Lockheed Martin seems to think their gold sun-shield wrapped tanks will
work with the winged lander/ascent vehicle that requires no ground
refueling.
https://youtu.be/vLpZUMfIJX0?t=1m4s
Tank farm for redundancy, so the story line is going to have to change a
bit. The micrometeorite hitting the solar panel first and breaking up into
a spray of shotgun pellets and debris that impacts the tank farm.
For Oxygen and Hydrogen, if a fuel cell is added for backup energy, water
generation, and breathing oxygen out of the cryogenic tank, would mean that
there is a slow uses rate of the Cryogenic Oxygen and Hydrogen. This
propellant use rate if implemented properly can give additional cooling to
the propellants during the long trip. Essentially a flash evaporator inside
the tank so that the propellant to be used for whatever purpose, breathing,
drinking, energy, attitude thrusters and small burns will cool the bulk of
stored propellants.
For the design of this system, the flash evaporator is mounted inside the
tank away from the walls, it's a vacuum pipe like the evaporator coil on an
air conditioner. The propellant is fed through a capillary tube to flash
from a low pressure liquid to a near vacuum colder gas to absorb heat
before it exits the tank and enters the electric powered compressor (ac
compressors make great vacuum pumps). Multistage electric compressors to
supply Oxygen/Hydrogen for the fuel cell (or generator) to supply
electricity and another compressor stage to bring the Hydrogen up to 10,000
psi arc-jet thrusters. This yields system that has RCS with an ISP of
1600+, generates drinkable water, provides high pressure oxygen and
hydrogen, and cools the stored propellants.
Still better to store the propellants as a solid. But, all is not lost, if
they didn't forget to purchase an emergency thermal heat plug before
leaving Earth. Don't leave home without one.
On Sat, Jun 16, 2018 at 12:46 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Fri, 15 Jun 2018, Craig Fink wrote:Is this N2O2 performance in the 1600 ISP range? I guess the Nitrogen could
... and into the Primary Oxygen Tank creating a 100 cm diameter hole.
...it may not be a sensor glitch in Secondary Tank, the only backup for
the long burn ahead at Mars to return to Earth...
By the way, LOX is actually a rather unlikely choice as oxidizer for such
a ship. Keeping it liquid (never mind solid) for months is too much of a
headache, when crew and electronics need to be kept at roughly room
temperature, and temperatures in that general neighborhood are the natural
equilibrium temperature in the inner solar system. Room-temperature
propellants are heavily favored, especially for systems that are crucial
to safe return.
If the performance of something like N2O4 is inadequate, use ClF5. Needs
more careful handling, but delivers LOX-class performance and stores at
room temperature (under a bit of pressure, like N2O4). 1960s proposals
for Mars expeditions often show ClF3 in the oxidizer tanks (ClF5 being
then a recent discovery and still under wraps).
