Author Topic: Dennis Tito's Inspiration Mars Foundation Pre Announcement Thread  (Read 166224 times)

Offline MATTBLAK

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Re: Inspiration Mars Foundation Press Conference
« Reply #200 on: 02/23/2013 09:25 am »
Mixed launch fleet launch sequence: 1x Falcon Heavy - Earth Departure Stage #1  (LOX/CH4 or LOX/RP1).
1x Falcon Heavy with the Long Trunk Habitat/Logistics and hypergolic propulsion module.
1x Falcon 9.1 with Dragon Rider Command craft and crew.
1x Atlas 552 with Centaur twin engined EDS #2.

If this is going to work, it has to be one launch. Everything else starts getting in the billions and is much too complex to pull off in such a short time.

And no reconfiguration of the spacecraft after TMI. Imagine you are after TMI and something goes wrong with the rotation of the dragon and docking to the service module. Since you won't be able to carry EVA equipment due to mass constraints, you're dead.

The following might work: the falcon heavy as it is planned now suffers very much for high energy trajectories because it is not yet optimized for those. Spacex might have a better upper stage engine available in 2018, but it is probably not a good idea to depend on their schedule estimates for something like this.

So you could have a dragon with a service module with some additional living space, ECLSS, a docking adapter, and a propulsion system for some 1000m/s. Launch the stack into a highly elliptical earth orbit (28°, 20000x200km or so) using the falcon heavy upper stage, turn the dragon around and redock to the service module, and do the actual TMI using the service module, with the dragon turned around, during the next perigee pass.

That way, you can abort in case something goes wrong with the reconfiguration, and you increase the TMI throwmass a lot.

I think they will propose to tough it out without any additional living space. But with the payload numbers published for FH (53t to LEO, but just 12t to 28° GTO) they will need some kind of upper stage for the TMI in any case.

Sorry; but I just don't see how they could do even a minimum-mass, 2 person mission like this in one launch unless it were a SLS Block 2 - which is not going to happen - and even then it would be a stretch.

2x Falcon Heavy? I'm not sure - Launch #1: EDS. Launch #2: Dragon Rider, Habitat & Hypergolic Propulsion Stage. Rendezvous and dock in low Earth orbit and depart. But would that EDS have enough delta-v to push the stack to TMI with LOX/Kerosene as the propellant? I don't know. A 3x launch solution with 2x Falcon Heavy & 1x Falcon 9.1? Sounds more plausible if you crunch the numbers. But without a Propellant Depot waiting at L-1 or L-2 it seems to me that any Mars or NEA mission could not be done in a single launch without that launcher being able to throw at least 35 metric tons to escape velocity.
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Offline MATTBLAK

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Re: Inspiration Mars Foundation Press Conference
« Reply #201 on: 02/23/2013 09:31 am »


I think they will propose to tough it out without any additional living space.

There is a limit to how much you can tough it out.  Ten cubic m just is not enough for two people over 500 days, not when all the onboard equipment cuts it to half this.

Ten cubic meters (353 feet) per crew member might be tolerable (barely) if the following factors are taken into account: Communications with Earth are strong and reliable. The food is good, there is a vast digital entertainment library to amuse the crew, the toilet facilities are reliable, the exercise equipment is decent, even if basic... I could go on, but I think people get my drift.
« Last Edit: 02/23/2013 09:31 am by MATTBLAK »
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Offline rklaehn

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Re: Inspiration Mars Foundation Press Conference
« Reply #202 on: 02/23/2013 09:39 am »
But without a Propellant Depot waiting at L-1 or L-2 it seems to me that any Mars or NEA mission could not be done in a single launch without that launcher being able to throw at least 35 metric tons to escape velocity.

I agree. But we are not talking about a mars mission but about a mars flyby mission. This makes a huge difference. It is probably less than 2 km/s more than GTO. A single falcon heavy could lift 25t to an intermediate elliptic orbit, from which you can get to TMI with the required C3 with an upper stage such as an ATK Castor.

Supply requirements are, from the top of my head:
~ 5kg/man/day (very conservative),
~ 3.5kg/man/day (current state of the art),
~ 1-2kg/person/day (advanced life support system)?

So if you use a simple and light life support system, you need just 5000kg of consumables. You don't need 35t to C3=0 for a flyby. 35t to C3=0 is roughly the mars direct budget for a four-person mission that lands on mars.

The biggest problem is the lack of volume. And of course it is a pretty high risk mission.

Offline DLR

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Re: Inspiration Mars Foundation Press Conference
« Reply #203 on: 02/23/2013 09:46 am »
What about using a modified Falcon 9 US as a "wet workshop", simply to give the astronauts a bit more room?


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Re: Inspiration Mars Foundation Press Conference
« Reply #204 on: 02/23/2013 10:15 am »
What about using a modified Falcon 9 US as a "wet workshop", simply to give the astronauts a bit more room?

That would require using the F9 US to do the TMI, which is not possible unless you have an unrealistically low consumables mass budget. Also, you would have to do the conversion to habitable volume while on an interplanetary trajectory, with no way to abort if something goes wrong.

An upper stage and a space station / habitable volume are both highly mass-optimized, specialized machines. They don't have that much in common except that both are pressure vessels. So conversion from one to the other is not as simple as people seem to think.

For additional habitable volume you would be better off using a bigelow beam or a stripped-down dragon pressure vessel without heatshield and propulsion.

But note that docking something to the dragon will block the draco engines that are most efficient for orbit correction maneuvers.

Offline Dalhousie

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Re: Inspiration Mars Foundation Press Conference
« Reply #205 on: 02/23/2013 10:19 am »


I think they will propose to tough it out without any additional living space.

There is a limit to how much you can tough it out.  Ten cubic m just is not enough for two people over 500 days, not when all the onboard equipment cuts it to half this.

Ten cubic meters (353 feet) per crew member might be tolerable (barely) if the following factors are taken into account: Communications with Earth are strong and reliable. The food is good, there is a vast digital entertainment library to amuse the crew, the toilet facilities are reliable, the exercise equipment is decent, even if basic... I could go on, but I think people get my drift.

Studies suggest that 5 cubic m per person free space is the survival minimum for durations over 6 months, 10 m free space is the functional minimum. Pressuised volume is two to three times free space.

Dragon has 10 m pressuised volume in total.  Barely enough for one at best, certainly not enough for two atunder any circumstances for such a mission.
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Offline Dalhousie

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Re: Inspiration Mars Foundation Press Conference
« Reply #206 on: 02/23/2013 10:23 am »




I think they will propose to tough it out without any additional living space.

There is a limit to how much you can tough it out.  Ten cubic m just is not enough for two people over 500 days, not when all the onboard equipment cuts it to half this.

Nevertheless that is what I suspect they will propose.

If they propose that, then that alone is enough to kill it.
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Offline R7

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Re: Inspiration Mars Foundation Press Conference
« Reply #207 on: 02/23/2013 10:32 am »
Assuming a very simple life support system, you would have 5kg/man/day * 500 days * 2 pax = 5000kg for provisions. Add 1000kg for the life support system itself, 4200kg for the dragon and 1000kg for propellant for midcourse corrections, you end up with just 11.2t.

Is increased radiation protection somewhere in those numbers, or just fly stock Dragon and see how it goes? FH quoted GTO payload is 12t, going to be tough without some high energy kick stage.
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Offline DLR

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Re: Inspiration Mars Foundation Press Conference
« Reply #208 on: 02/23/2013 10:35 am »
What about using a modified Falcon 9 US as a "wet workshop", simply to give the astronauts a bit more room?

That would require using the F9 US to do the TMI, which is not possible unless you have an unrealistically low consumables mass budget. Also, you would have to do the conversion to habitable volume while on an interplanetary trajectory, with no way to abort if something goes wrong.

An upper stage and a space station / habitable volume are both highly mass-optimized, specialized machines. They don't have that much in common except that both are pressure vessels. So conversion from one to the other is not as simple as people seem to think.

For additional habitable volume you would be better off using a bigelow beam or a stripped-down dragon pressure vessel without heatshield and propulsion.

But note that docking something to the dragon will block the draco engines that are most efficient for orbit correction maneuvers.

If the Falcon US performs the TMI burn, the mass budget would be around ~10 tonnes. Perhaps enough for a Dragon, supplies, an ECLSS and a docking adapter on the Falcon US.
I also think two astronauts would be streching it. A one-man mission should be feasible though.

Offline Dalhousie

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Re: Inspiration Mars Foundation Press Conference
« Reply #209 on: 02/23/2013 10:35 am »
And of course it is a pretty high risk mission.

People keep saying this, but why?
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Offline rklaehn

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Re: Inspiration Mars Foundation Press Conference
« Reply #210 on: 02/23/2013 10:37 am »
Nevertheless that is what I suspect they will propose.

If they propose that, then that alone is enough to kill it.

Why? The only thing that can (and most likely will) kill this mission is a lack of funding.

If the likelihood of the crew going insane is high, it will make getting advertising funding more difficult. Except maybe for antidepressants.

But assuming that dennis tito has managed to increase his net worth substantially, and is willing to liquidate it all, who's going to stop him?

I know that there is a law for everything in the US, but as far as I know engaging in expensive and very dangerous activities is not yet outlawed, except maybe in NYC.

Offline Bernie Roehl

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Re: Inspiration Mars Foundation Press Conference
« Reply #211 on: 02/23/2013 10:45 am »
I also think two astronauts would be streching it. A one-man mission should be feasible though.

I was about to say the same thing. Why is everyone assuming a two person crew?

A one person mission has half the consumables and twice the volume per person. No risks of interpersonal conflict during the mission either.

Yes, the person would be lonely.  But I suspect that would be better than two people at each others‛ throats after six months.
« Last Edit: 02/23/2013 10:48 am by Bernie Roehl »

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Re: Inspiration Mars Foundation Press Conference
« Reply #212 on: 02/23/2013 10:46 am »
Is increased radiation protection somewhere in those numbers, or just fly stock Dragon and see how it goes? FH quoted GTO payload is 12t, going to be tough without some high energy kick stage.

In the beginning of the mission you would try to spend as much time as possible inside your huge pile of water-rich consumables, which should afford some protection.

For the end of the mission you would have to either retain the mass (yuck!) or just accept an increased risk of cancer due to cosmic radiation and hope you don't get fried by a solar flare.

The mission is roughly at the time of the next solar minimum, so the danger of solar flares is not very high.

And of course it is a pretty high risk mission.

People keep saying this, but why?

There is a risk of a life support system breakdown. Then, as you have pointed out, there is the risk of the crew developing psychological problems and doing something stupid. And then of course there is the risk of launch and reentry, and the risk of being hit by a solar flare.

Still safer than many other extreme adventure activities like wingsuit flying though.

Offline Dalhousie

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Re: Inspiration Mars Foundation Press Conference
« Reply #213 on: 02/23/2013 10:47 am »
A one-man mission should be feasible though.

Technically, yes, from from a human point of view that would be very challenging.  500 days is much longer than even non-stop solo circumnavigations (typically 10 months or less) or the longest solo stints in the polar regions (none I know of more than 12 months).
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Offline MATTBLAK

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Re: Inspiration Mars Foundation Press Conference
« Reply #214 on: 02/23/2013 10:48 am »




I think they will propose to tough it out without any additional living space.

There is a limit to how much you can tough it out.  Ten cubic m just is not enough for two people over 500 days, not when all the onboard equipment cuts it to half this.

Nevertheless that is what I suspect they will propose.

If they propose that, then that alone is enough to kill it.

Then two Dragons docked nose-to-nose - one is the Command & Earth re-entry vehicle, the other purely for Hab & Logistics (lots of Hi-density polyethylene for shielding, too). But both Dragons have 'Long Trunks' with that trunk space dedicated to being a service module; containing oxygen, nitrogen & water tanks, helium pressurization tanks, about six tons of hypergolic propellants and a single restartable engine. Dual Launch each vehicle on a Falcon Heavy (from two Pads, but what interval?) and directly to escape velocity on very similar trajectories. The two craft then rendezvous and dock nose-to-nose after discarding their Earth Departure stages.

On to a Mars Flyby...
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Offline aquanaut99

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Re: Inspiration Mars Foundation Press Conference
« Reply #215 on: 02/23/2013 10:48 am »
Yes, the person would be lonely.  But I suspect that would be better than two people at each others‛ throats after six months.

A one person crew is the only possible way to do this. Perferably, that one person is a petite female (women consume less food, water and oxygen than men, and are also able to tolerate confined spaces better).

The psychological hurdles are immense tho.

Offline Dalhousie

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Re: Inspiration Mars Foundation Press Conference
« Reply #216 on: 02/23/2013 10:50 am »
Nevertheless that is what I suspect they will propose.

If they propose that, then that alone is enough to kill it.

Why? The only thing that can (and most likely will) kill this mission is a lack of funding.

If the likelihood of the crew going insane is high, it will make getting advertising funding more difficult. Except maybe for antidepressants.

But assuming that dennis tito has managed to increase his net worth substantially, and is willing to liquidate it all, who's going to stop him?

I know that there is a law for everything in the US, but as far as I know engaging in expensive and very dangerous activities is not yet outlawed, except maybe in NYC.

Because ignoring basic requirments for volume is like ignoring requirements for consumables.

Apologies in advance for any lack of civility - it's unintended

Offline MATTBLAK

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Re: Inspiration Mars Foundation Press Conference
« Reply #217 on: 02/23/2013 10:50 am »
I also think two astronauts would be streching it. A one-man mission should be feasible though.

I was about to say the same thing. Why is everyone assuming a two person crew?

A one person mission has half the consumables and twice the volume per person. No risks of interpersonal conflict during the mission either.

Yes, the person would be lonely.  But I suspect that would be better than two people at each others‛ throats after six months.

You're reaching - There were a couple of incidents like that on the Salyuts and Mir, yes. But they were very rare and you can't use them as an excuse to not try something like this. It goes with the territory.
« Last Edit: 02/23/2013 10:51 am by MATTBLAK »
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Offline Dalhousie

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Re: Inspiration Mars Foundation Press Conference
« Reply #218 on: 02/23/2013 10:56 am »
I also think two astronauts would be streching it. A one-man mission should be feasible though.

I was about to say the same thing. Why is everyone assuming a two person crew?

A one person mission has half the consumables and twice the volume per person. No risks of interpersonal conflict during the mission either.

Yes, the person would be lonely.  But I suspect that would be better than two people at each others‛ throats after six months.

Why would a properly chosen pair be at each other's throats after six months? Two person exploration teams in space or the poles have been very successful in the past.

One person alone for this duration is uncharted territory for a complex missions.  One person is less likely to cope with technical problems than two.
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Offline MATTBLAK

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Re: Inspiration Mars Foundation Press Conference
« Reply #219 on: 02/23/2013 11:04 am »
And sorry to be so pragmatic - but if one crew member died of a heart attack, stroke or whatever - then the remaining person could carry on the mission. But with a one person crew dying? No mission. But on a two person crew: what would they do with the body!!

If they had pressure suits onboard, perhaps the remaining crewmember would have to depressurize and give them a Space burial...  :-\
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