Author Topic: Mars Direct updated for the 21st Century  (Read 641 times)

Offline redliox

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Mars Direct updated for the 21st Century
« on: 05/01/2017 04:14 PM »
Initially I began a thread in the SpaceX department inquiring about applying the ITS booster toward the original Mars Direct effect vehicles.  MATTBLAK quoted:
The traditional Mars Direct by Robert Zubrin and David Baker had Direct vehicles of about 45 tons being sent on Trans-Mars Injection. This is about what the SLS Block II with 'Dark Knights' solid boosters could achieve with an Exploration Upper Stage. If the corestage was redesigned for 5x RS-25E and the EUS had slightly higher thrust engines, this could raise the Direct Vehicle's masses to about 50 tons.

We probably need to have a new thread about Mars Direct redesigned for alternate launch vehicles such as New Glenn, Vulcan/ACES and Falcon Heavy

When Baker and Zubrin conceived Mars Direct back in the 1990s there was only the space shuttle and, at best, the Titan rockets available with no signs of commercial rocketry beyond the ULA monopoly or perpetually-stalled-pie-in-the-sky plans within NASA.  20 years later now, we miraculously have a new world opening up despite the end of the space shuttle.  There may quickly be a huge range of options Mars Direct launchers to utilize for a plan created when there essentially were none.

The thread rules are the following:
1) Assume we wish to land 20+ metric ton vehicles onto the Martian surface with as minimal an architecture as possible - i.e. at least 2 but not more than 4 vehicles and launchers per expedition to Mars
2) Debate any launch vehicle from any company so long as it has the ability to throw over 20 metric tons to Mars
3) Focus discussion on launch vehicles that are active as of 2010 onward; we are trying to update Mars Direct's options
4) Discuss the ITS booster as a launcher but NOT the ITS spaceship as one; the spaceship isn't a launch vehicle by itself applicable to Mars
"Let the trails lead where they may, I will follow."

Offline sevenperforce

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Re: Mars Direct updated for the 21st Century
« Reply #1 on: 05/01/2017 08:17 PM »
Build your 20-tonne vehicle with methalox engines, loft it as the upper stage on Falcon Heavy, refuel it in LEO, and send it on its way.

As long as you can aerobrake at Mars, you're golden.
« Last Edit: 05/01/2017 08:17 PM by sevenperforce »

Offline KelvinZero

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Re: Mars Direct updated for the 21st Century
« Reply #2 on: 05/18/2017 10:32 AM »
This is something I sort of wanted to ask before but this makes it a bit more topical.

around the 3 minute mark, he says that if you can refuel a vehicle in orbit it's a very valuable thing to do.

Would it still count as Mars Direct (Updated for the 21st century) if it had many many refueling flights?

My loose understanding is that a large number of flights is against his philosophy.. but wouldn't that simply change if it became a standard proven practice?

The 21st century might be defined by F9R becoming mundane. The first stage to get that huge amount of fuel for an all chemical mission to mars into LEO is a huge part of the cost but IMO a small part of the architecture.


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Re: Mars Direct updated for the 21st Century
« Reply #3 on: 05/18/2017 11:52 AM »
Dual launches of 50+plus ton Commercial launchers could send 25-to-30 metric ton spacecraft on their way - be they Dragon-derived or the traditional 'Tuna Can' Mars Direct ships. Though, I've always had a bit of a soft spot for blunt-biconic spacecraft, which the Dragon 2.0 has more than a passing resemblance to. Using 2x Falcon Heavy in it's fully expendable mode allows for 120 tons into Low Earth Orbit. I once wrote a paper (too many details to reproduce here, and a bit obsolete in details) on how to do a basic 2 or 3 man Sortie/Flags/Footprints Martian mission to 'break the Dragon of impossibility's back and prototype a pioneering Manned Mars Mission. Larger, long stay missions could come later...

With the following, I'm drawing a broad sketch - some might go; "Yeah, but hang on - how does it..." Details might come later in a more detailed 'white paper' that I'll hammer out, if I get time. Then real engineers and scientists like Dr Pietrobon for instance could crunch the numbers, if they were so inclined...

A: A Dragon 2 based Earth Return Vehicle is pre-deployed to Martian orbit with a Transit Hab docked to it's nose - inflatable or stretched Cygnus-derived. The Dragon ERV has an extended Trunk that has a 'Propulsion Pallet' fueled by about 20 tons or more of hypergolics and powered by a cluster of Dracos. We broadly assume that this craft had been braked into Martian orbit previously by an expendable, storable propellant propulsion stage.

B: On the surface of Mars at a pre-chosen landing site are 2x upgraded Red Dragon Cargo landers. One contains a Solar/RTG/Stirling generator unit for ISRU and Expedition surface power. The other has food, water, tools and equipment - including a simple Apollo-style Martian Roving Vehicle - carried in a conformal, aerodynamic 'bulge' shell on the outside hull of the Dragon. A matching conformal shell on the other side carries other gear. Once emptied, this Cargo Lander can also act as a Surface Habitat.

C: As near as possible (200 meters or less) to the pre-landed Cargo/Hab Dragons is a third craft: A Dragon based Mars Ascent Vehicle. The only cargo this craft lands is a supply of Hydrazine fuel. A small robot rover unspools a power cable from the Power Cargo lander and plugs it into the Ascent Vehicle. The Ascent Vehicle sucks in and cracks Martian CO2, dumping Carbon Monoxide overboard and storing Liquid Oxygen in it's oxidizer tanks.

CREW LAUNCH: In fully expendable mode, a Falcon Heavy places into LEO a crewed Red Dragon spacecraft with a propulsion pallet-equipped Extended Trunk. It carries 2x Astronauts. A second Falcon Heavy launches with a small Transit Hab attached to the top of it's second stage. The Transit Hab will mass about 7 tons with it's supplies and equipment if it's based on an enhanced Cygnus, or lighter if an inflatable. The second Falcon Heavy's upper stage retains about 50 tons of propellant from it's ascent to orbit. The Crewed Dragon docks with the Transit Hab mounted atop the Falcon second stage and the combined crafts burn out of Earth orbit on Trans-Mars Injection; using all of the Falcon stage's propellant and most of the crewed Dragon's propulsion pallet. Enough fuel is retained in the propulsion pallet for 2 or 3 course correction burns or an abort burn past Mars if necessary later in the mission. The Transit Hab contains enough crew supplies for a months-long cruise back to Earth if needed. But during a nominal mission; these supplies would be jettisoned, along with the Trans Hab.

The Crew Dragon cruises to Mars and when on final approach, the Transit Hab and Trunk are jettisoned and the crewed Red Dragon performs a direct entry descent to the Martian surface, right near the pre-deployed Dragon assets. Depending on when the precise years the Launch windows are set in, and on the trajectory used; the surface stay and exploration would be anywhere from two to four weeks. The crew would then have to board the now fully-fueled Mars Ascent Dragon and climb to rendezvous and dock with the Earth Return Dragon vehicle...

Now; this bare-bones basic mission concept could be augmented with extra equipment and modules launched every launch window - more Mars surface power units and supplies landed to increase the Martian stay to more than a year. An inflatable surface Habitat to allow the crew to increase to 3 or even 4 Astronauts... And a larger Transit Hab to allow room and supplies for a larger crew, outbound to Mars...

Yes; I know this isn't as grandiose or 'sexy' as either Elon's Interplanetary Colonial Transport system, or even NASA's slightly nebulous plans... But that's the point! Do it fast, do it minimalist and 'dirty', and break ground - 'guerilla' fashion. But it would still be asking a great deal of both the available technology and also the tech that is still to come.
« Last Edit: 05/21/2017 11:23 AM by MATTBLAK »
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