Eagle1Division
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With the 90 day report being a huge roundabout, inefficient way to reach Mars and the Mars Reference Design Mission, following the late-NASA tradition of "not the cheapest possible", SpaceX CEO Elon Musk wants to go to Mars, and build a permanent colony there. The ultimate objective: Make going to Mars, as expensive as a mid-upper class home in California.
To do this, the price of traveling to Mars needs to be lowered, drastically. SpaceX will reduce LEO access prices drastically, once again, using entirely re-usable spacecraft.
But the price of going to Mars still needs to come down.
Mars Reference Design Mission (MRDM v5), is a joke. With roughly a thousand tons placed into orbit, only a tiny fraction makes it to Mars, and only a tiny capsule splashes back down to Earth.
As for the back-to-Mars infrastructure, the rockets, and vehicles, they're all either smashed up somewhere or flinging into interplanetary space.
An entirely new and radically re-usable mission architecture is called for, for continuing service to Mars to be possible.
The objective: Lower trans-Mars costs as much as possible, with a sustainable program.
My proposal, I'll quickly dub it "Mars Forever", uses reusable Falcon launch vehicles (prime candidate: Falcon X) to haul a fleet of 3 types of vehicles and a module into orbit.
1 - Trans-Mars Bus
The Bus is built so that it can be assembled in two launches, and uses it's propellant tanks to provide radiation shielding for an inner payload area. It uses 3 [ame="http://en.wikipedia.org/wiki/Project_Timberwind"]Timberwind-Class[/ame] NTR engines (ISP=1,000 sec, Propellant: LH2).
2- ERV
The ERV is essentially a heavily modified Dragon spacecraft, called the "Crimson-Dragon" with a "Command Module"-like "ERV Body" attached on the bottom. The entire vehicle can sustain Martian interplanetary aeroentry, houses multiple ISRU units for redundancy, and has a maximum Delta-Vee in excess of 7,500 m/s using 370 sec ISP LOX-CH4 engines, allowing it to directly return to Earth, and carries the bare minimum provisions for the trip duration, one-way.
(On Mars surface, supplies restocked by the HAB.)
In case of a dire emergency, the Crimson-Dragon spacecraft can be separated from the ERV body, with enough Crimson-Dragon heat shielding to make an Earth aeroentry from Mars.
3- HAB
The HAB is simply a heat shield+Mars surface habitat, with the accompanying landing equipment.
4 (module) - Bushab
The Bushab is a small, very lightweight habitat module that carries provisions, life support, and a basic loadout of equipment for the trans-Martian flight (exercise equipment, small shower, etc.). It, docked with the ERV, is the habitat for the interplanetary flight. It's additional perishables allow for higher crew moral, and enough provisions for a free-return to Earth, in the event that the crew cannot continue to Mars surface.
Phase 1: Construction/Cargo Flight
4 heavy launches.
Or
3 heavy launches + medium launch.
The bus is launched in 2 launches, assembled, then docked with a HAB and ERV.
The Bus-cargo assembly makes the first Delta-Vee maneuver required; TMI/Earth Escape, on the lowest energy trajectory possible with free return capability.
On arrival to Mars, the ERV and HAB undock, and aerocapture/land on Mars. The Bus, however, makes no significant Delta-Vee adjustments (other than minor, necessary course correction burns), and makes a hyperbolic free-return trajectory back to Earth.
Upon arrival to Earth, the bus is no longer carrying any cargo, so the propellant requirements for Earth Orbit Capture are exceedingly small. It then performs EOI into LEO.
Phase 2: Manned Flight
2 heavy launches.
Propellant for the HAB is launched, as well as another ERV along with a Bushab.
The propellant is transferred, the Bushab and the ERV dock to the Bus.
The Bushab is significantly lighter than the HAB, meaning that this flight can use a higher energy trajectory.
Upon arrival to Mars, the ERV undocks, and aerocaptures/lands on Mars, and the Bushab remains docked to the Bus.
Once again, the Bus flies a free return trajectory, and performs EOI to LEO with Bushab attached.
Phase 3: Manned Return
1 Heavy launch.
1 medium launch or ISS docking.
Propellant is delivered to the Bus.
Stationkeeping/housecleaning performed in LEO of the Bushab.
The Bus performs TMI. As it passes by Mars, the ERV launches on a near identical interplanetary trajectory. Both on hyperbolic Earth trajectory, they meet and dock. Then, on arrival to Earth, the bus+bushab+ERV performs EOI to LEO with the 3xTimberwind NTR's.
This mission requires an almost identical Delta-Vee to "Phase 2: Manned flight."
(One possibility to consider, is that the ERV could carry additional CH4 or LH2 attained through ISRU, and transfer it to the Bus, allowing for a higher-energy trajectory for a shorter flight time.)
In case the docking fails, or the NTR's fail, the ERV is capable of returning to Earth without the bus, by separating the Crimson-Dragon module. The result is loss of ERV in the event of docking/rendevous failure, and Bus+ERV loss in case of NTR failure, but never loss of crew.
But here's where there's the big benefits to the architecture, it's not designed for a single Mars mission, but continuing service to Mars.
Continuing Service to Mars:
1 Heavy launch
1 Medium launch
The heavy launch delivers propellant to the Bus, which is in LEO.
The medium launch delivers fresh perishables and crew. (optional: The Crimson-Dragon may be able to safely undock from the ERV Body, allowing it to return to Earth for servicing on the surface. In this case, instead of launching a regular Dragon to deliver perishables and service the Bushab, A Crimson-Dragon is launched with fresh perishables and crew to replace the old Crimson-Dragon. Purely optional, depending on how beneficial it is.)
TMI.
Mars Arrival, the ERV undocks, aerocaptures, and lands, while the Bus+bushab flies a free-return trajectory back to Earth.
Bus performs EOI to LEO, with Bushab.
-OR
In later years, the bus could carry larger propellant tanks with additional LH2, and a modified ERV could deliver additional LH2 propellant for the Bus from facilities on Mars. Allowing an ERV to launch, dock with the Bus for the return trip, and use the additional LH2 to perform EOI to LEO with the additional cargo mass of the ERV.
Continuing Service To Earth
1 heavy launch.
Propellant for the Bus is delivered. Bus departs for Mars free-return carrying Bushab.
ERV launches and docks during interplanetary flight from Mars to Earth.
Bus performs EOI to LEO with Bushab and ERV docked.
---
I'll post additional details and illustrations when 3d Gmax models are made...
To do this, the price of traveling to Mars needs to be lowered, drastically. SpaceX will reduce LEO access prices drastically, once again, using entirely re-usable spacecraft.
But the price of going to Mars still needs to come down.
Mars Reference Design Mission (MRDM v5), is a joke. With roughly a thousand tons placed into orbit, only a tiny fraction makes it to Mars, and only a tiny capsule splashes back down to Earth.
As for the back-to-Mars infrastructure, the rockets, and vehicles, they're all either smashed up somewhere or flinging into interplanetary space.
An entirely new and radically re-usable mission architecture is called for, for continuing service to Mars to be possible.
The objective: Lower trans-Mars costs as much as possible, with a sustainable program.
My proposal, I'll quickly dub it "Mars Forever", uses reusable Falcon launch vehicles (prime candidate: Falcon X) to haul a fleet of 3 types of vehicles and a module into orbit.
1 - Trans-Mars Bus
The Bus is built so that it can be assembled in two launches, and uses it's propellant tanks to provide radiation shielding for an inner payload area. It uses 3 [ame="http://en.wikipedia.org/wiki/Project_Timberwind"]Timberwind-Class[/ame] NTR engines (ISP=1,000 sec, Propellant: LH2).
2- ERV
The ERV is essentially a heavily modified Dragon spacecraft, called the "Crimson-Dragon" with a "Command Module"-like "ERV Body" attached on the bottom. The entire vehicle can sustain Martian interplanetary aeroentry, houses multiple ISRU units for redundancy, and has a maximum Delta-Vee in excess of 7,500 m/s using 370 sec ISP LOX-CH4 engines, allowing it to directly return to Earth, and carries the bare minimum provisions for the trip duration, one-way.
(On Mars surface, supplies restocked by the HAB.)
In case of a dire emergency, the Crimson-Dragon spacecraft can be separated from the ERV body, with enough Crimson-Dragon heat shielding to make an Earth aeroentry from Mars.
3- HAB
The HAB is simply a heat shield+Mars surface habitat, with the accompanying landing equipment.
4 (module) - Bushab
The Bushab is a small, very lightweight habitat module that carries provisions, life support, and a basic loadout of equipment for the trans-Martian flight (exercise equipment, small shower, etc.). It, docked with the ERV, is the habitat for the interplanetary flight. It's additional perishables allow for higher crew moral, and enough provisions for a free-return to Earth, in the event that the crew cannot continue to Mars surface.
Phase 1: Construction/Cargo Flight
4 heavy launches.
Or
3 heavy launches + medium launch.
The bus is launched in 2 launches, assembled, then docked with a HAB and ERV.
The Bus-cargo assembly makes the first Delta-Vee maneuver required; TMI/Earth Escape, on the lowest energy trajectory possible with free return capability.
On arrival to Mars, the ERV and HAB undock, and aerocapture/land on Mars. The Bus, however, makes no significant Delta-Vee adjustments (other than minor, necessary course correction burns), and makes a hyperbolic free-return trajectory back to Earth.
Upon arrival to Earth, the bus is no longer carrying any cargo, so the propellant requirements for Earth Orbit Capture are exceedingly small. It then performs EOI into LEO.
Phase 2: Manned Flight
2 heavy launches.
Propellant for the HAB is launched, as well as another ERV along with a Bushab.
The propellant is transferred, the Bushab and the ERV dock to the Bus.
The Bushab is significantly lighter than the HAB, meaning that this flight can use a higher energy trajectory.
Upon arrival to Mars, the ERV undocks, and aerocaptures/lands on Mars, and the Bushab remains docked to the Bus.
Once again, the Bus flies a free return trajectory, and performs EOI to LEO with Bushab attached.
Phase 3: Manned Return
1 Heavy launch.
1 medium launch or ISS docking.
Propellant is delivered to the Bus.
Stationkeeping/housecleaning performed in LEO of the Bushab.
The Bus performs TMI. As it passes by Mars, the ERV launches on a near identical interplanetary trajectory. Both on hyperbolic Earth trajectory, they meet and dock. Then, on arrival to Earth, the bus+bushab+ERV performs EOI to LEO with the 3xTimberwind NTR's.
This mission requires an almost identical Delta-Vee to "Phase 2: Manned flight."
(One possibility to consider, is that the ERV could carry additional CH4 or LH2 attained through ISRU, and transfer it to the Bus, allowing for a higher-energy trajectory for a shorter flight time.)
In case the docking fails, or the NTR's fail, the ERV is capable of returning to Earth without the bus, by separating the Crimson-Dragon module. The result is loss of ERV in the event of docking/rendevous failure, and Bus+ERV loss in case of NTR failure, but never loss of crew.
But here's where there's the big benefits to the architecture, it's not designed for a single Mars mission, but continuing service to Mars.
Continuing Service to Mars:
1 Heavy launch
1 Medium launch
The heavy launch delivers propellant to the Bus, which is in LEO.
The medium launch delivers fresh perishables and crew. (optional: The Crimson-Dragon may be able to safely undock from the ERV Body, allowing it to return to Earth for servicing on the surface. In this case, instead of launching a regular Dragon to deliver perishables and service the Bushab, A Crimson-Dragon is launched with fresh perishables and crew to replace the old Crimson-Dragon. Purely optional, depending on how beneficial it is.)
TMI.
Mars Arrival, the ERV undocks, aerocaptures, and lands, while the Bus+bushab flies a free-return trajectory back to Earth.
Bus performs EOI to LEO, with Bushab.
-OR
In later years, the bus could carry larger propellant tanks with additional LH2, and a modified ERV could deliver additional LH2 propellant for the Bus from facilities on Mars. Allowing an ERV to launch, dock with the Bus for the return trip, and use the additional LH2 to perform EOI to LEO with the additional cargo mass of the ERV.
Continuing Service To Earth
1 heavy launch.
Propellant for the Bus is delivered. Bus departs for Mars free-return carrying Bushab.
ERV launches and docks during interplanetary flight from Mars to Earth.
Bus performs EOI to LEO with Bushab and ERV docked.
---
I'll post additional details and illustrations when 3d Gmax models are made...
