Author Topic: Dennis Tito's Inspiration Mars Foundation Pre Announcement Thread  (Read 85578 times)

Offline simonbp

Re: Inspiration Mars Foundation Press Conference
« Reply #180 on: 02/23/2013 03:04 AM »
Had a thought about a hab module for this venture. You could use the Thales pressurized module for the Cygnus with some modifications.

Even simpler: Inflatable airlock mounted in place of the docking ring. It means the crew can EVA without needing to depressurize the cabin. Then, you can store all the extra food, water, air, etc in the trunk and just EVA out to get it occasionally. No hab module needed.

Offline simonbp

Re: Inspiration Mars Foundation Press Conference
« Reply #181 on: 02/23/2013 03:10 AM »
That painted a mental picture in my mind of someone getting into an internet argument then spending a billion dollars to flyby Mars just to "prove a point." (And, of course, it didn't change anyone's mind. ;))

Well, they did kinda build Biosphere 2 just to prove a point, at a cost of $200 million, and Tito paid about $20 million to be the first space tourist. These people seem to know about spending vast sums of private money to prove points...

Offline Nathan

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Re: Inspiration Mars Foundation Press Conference
« Reply #182 on: 02/23/2013 03:37 AM »
I ike this kind of trailblazing. I would ave thought one person in a dragon could have done it but not two without some form of extra space.
What this says to me is that perhaps they are actually building a transit habitat that they hope to market to nasa in future years. Dragon would just take the crew to it and may or ay not be along for the ride. The comment that any launch vehicle or capsule would be used suggests that the capsule isn't the main vehicle they are using for this flyby.
Given finite cash, if we want to go to Mars then we should go to Mars.

Online Zed_Noir

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Re: Inspiration Mars Foundation Press Conference
« Reply #183 on: 02/23/2013 03:54 AM »
Had a thought about a hab module for this venture. You could use the Thales pressurized module for the Cygnus with some modifications.

Even simpler: Inflatable airlock mounted in place of the docking ring. It means the crew can EVA without needing to depressurize the cabin. Then, you can store all the extra food, water, air, etc in the trunk and just EVA out to get it occasionally. No hab module needed.

Didn't the Russians try the inflatable route and find it hazardous.

Why would you do EVA if you can avoided it to began with. No need for all the EVA gear (EVA suit, ECLSS, umbilicals, external spacecraft handhelds, airlock, etc.) when you can just open a hatch and drift into the hab module. Not taking into consideration the time & cost to have EVA suit rated for BEO uses. I don't think the ISS EVA suits are rated for BEO.

Finally you are proposing to store stuff in vacuum in the trunk?

Offline MATTBLAK

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Re: Inspiration Mars Foundation Press Conference
« Reply #184 on: 02/23/2013 04:29 AM »
Space X has a concept for an 'extended trunk' Dragon - Perhaps Space X could be commissioned to build a pressurized habitat/logistics module within that area: docking the main Dragon with it 'nose to tail', so to speak. And on top of that large trunk habitat/logistics module, instead of another Dragon capsule there could be a fair-sized hypergolic propulsion module that also has a set of solar arrays.

For just a crew of two; there's your mission module stack for Mars flyby - the habitat is filled with consumables and therefore is the storm shelter, too. Including propellants and consumables this Mission Module stack would easily mass more than 40 tons. Send it BEO with LOX/Methane or LOX/kerosene propulsion stages - or indeed also dock a twin engine Centaur stage with the stack as the final stage added shortly before TMI (avoiding LH2 boil off).

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.
« Last Edit: 02/23/2013 04:38 AM by MATTBLAK »
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Offline simonbp

Re: Inspiration Mars Foundation Press Conference
« Reply #186 on: 02/23/2013 06:13 AM »
And Earth entry at 14.2 km/s! Yowuch! That'll put the heat shield to a test!

Offline R7

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Re: Inspiration Mars Foundation Press Conference
« Reply #187 on: 02/23/2013 06:21 AM »
Basically no they're not doing a Venus swingby, but the perihelion almost gets down to Venus orbit.

How much dv required to inject into that orbit?

(IOW how much can FH deliver there)

edit:
Didn't the Russians try the inflatable route and find it hazardous.

The airlock wasn't. Leonov's suit had a problem being too stiff, and apparently he almost became stuck in the airlock by entering it the wrong way.

http://history.nasa.gov/monograph7.pdf page 2.
« Last Edit: 02/23/2013 06:31 AM by R7 »
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Offline Ralph Buttigieg

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Re: Inspiration Mars Foundation Press Conference
« Reply #188 on: 02/23/2013 06:31 AM »
G'day,

Any reason why a hatch couldn't be cut and installed through the bottom of the Dragon allowing access to a module in the trunk? The USAF was planning to do that with Gemini/MOL.

ta

Ralph

Space X has a concept for an 'extended trunk' Dragon - Perhaps Space X could be commissioned to build a pressurized habitat/logistics module within that area: docking the main Dragon with it 'nose to tail', so to speak. And on top of that large trunk habitat/logistics module, instead of another Dragon capsule there could be a fair-sized hypergolic propulsion module that also has a set of solar arrays.

« Last Edit: 02/23/2013 06:34 AM by Ralph Buttigieg »

Offline simonbp

Re: Inspiration Mars Foundation Press Conference
« Reply #189 on: 02/23/2013 06:32 AM »
How much dv required to inject into that orbit?

(IOW how much can FH deliver there)

Roughly speaking it will be close to the Apollo lunar free-return C3, which was about -1.4 km2/s2. So, call it -2.0 km2/2, to be safe, or 1.4 km/s beyond Earth escape velocity.

Offline rklaehn

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Re: Inspiration Mars Foundation Press Conference
« Reply #190 on: 02/23/2013 06:42 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.
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Offline QuantumG

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Re: Inspiration Mars Foundation Press Conference
« Reply #191 on: 02/23/2013 06:57 AM »
with the payload numbers published for FH (53t to LEO,

It's 53 tons inside a 2 ton fairing. You don't need the fairing for a crew mission.

they will need some kind of upper stage for the TMI in any case.

That's the conventional wisdom, yes.
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Offline R7

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Re: Inspiration Mars Foundation Press Conference
« Reply #192 on: 02/23/2013 07:16 AM »
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.

Will there be detente with ULA? A Centaur to kick Red Dragon on it's way. About 18mt then (including the empty kick stage).
« Last Edit: 02/23/2013 07:16 AM by R7 »
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Offline R7

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Re: Inspiration Mars Foundation Press Conference
« Reply #193 on: 02/23/2013 07:24 AM »
Any reason why a hatch couldn't be cut and installed through the bottom of the Dragon allowing access to a module in the trunk? The USAF was planning to do that with Gemini/MOL.

The heat shield. Very high reentry speed (~30% higher the Apollos) will be a challenge even without hatch in the middle.
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Offline rklaehn

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Re: Inspiration Mars Foundation Press Conference
« Reply #194 on: 02/23/2013 07:53 AM »
with the payload numbers published for FH (53t to LEO,

It's 53 tons inside a 2 ton fairing. You don't need the fairing for a crew mission.

The fairing gets dropped long before you even reach LEO. It is not going to make a big difference for an interplanetary trajectory.

Quote
they will need some kind of upper stage for the TMI in any case.

That's the conventional wisdom, yes.

The other alternative would be to have a very low budget for consumables (1kg/man/day) and have some very advanced life support system. But I think buying some kind of upper stage (something based on dracos or maybe a ATK Star or Castor motor) and using a simple life support system and 5 kg/man/day would be much more realistic than developing a very advanced life support system in 2 years.

If your TMI stage does not work, you are still in highly elliptical earth orbit and can return to earth using the dragon propulsion system. If your life support system fails, you're dead.

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.

Will there be detente with ULA? A Centaur to kick Red Dragon on it's way. About 18mt then (including the empty kick stage).

Integrating a LH2 upper stage with the falcon heavy would be much too compiex. But I think something a lot smaller and simpler would be enough.

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.
« Last Edit: 02/23/2013 07:58 AM by rklaehn »
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Offline Dalhousie

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Re: Inspiration Mars Foundation Press Conference
« Reply #195 on: 02/23/2013 08:22 AM »
Not taking into consideration the time & cost to have EVA suit rated for BEO uses. I don't think the ISS EVA suits are rated for BEO.

In what aspects does BEO vs LEO matter WRT a space suit?
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Offline rklaehn

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Re: Inspiration Mars Foundation Press Conference
« Reply #196 on: 02/23/2013 08:36 AM »
Not taking into consideration the time & cost to have EVA suit rated for BEO uses. I don't think the ISS EVA suits are rated for BEO.

In what aspects does BEO vs LEO matter WRT a space suit?

The temperature environment is different with half the sky filled by warm earth in LEO. And the radiation environment in LEO is much more benign than in deep space because you are inside the earth magnetic field. (Not that you can do anything about it with a space suit, anyway)

I think current LEO spacesuits would work just fine for short excursions BEO.

But for this mission I think there simply is no mass budget for a spacesuit, an airlock and all the assorted hardware associated with EVAs.
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Online guckyfan

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Re: Inspiration Mars Foundation Press Conference
« Reply #197 on: 02/23/2013 08:49 AM »

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.

........

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

Not critisizing, just a question. Would two launches really be that much more complex? You propose rearranging the stack after launch anyway and I agree it would be necessary.


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.

How about this kind of mission profile using two launchers? It should not increase mission cost that much.

Launch a Falcon 9 with the complete stack, Dragon, cargo and a small inflatable habitat. I just cannot imagine that everything will fit into a Dragon with two astronauts unless there is a very small but very efficient ECLSS that allows 1 or 2 kg/person/day. Rearrange the stack in LEO and check out all the equipment for proper function.
Added: The astronauts would spend a few weeks in LEO that way but in a 500 day mission 20 days extra with a lot of more space should be ok.

Launch a Falcon Heavy empty or if really necessary with some kind of kickstage. The second stage would reach LEO with almost full fuel tanks, less with a kickstage but still plenty. Enhance the loiter time in orbit should require not much more than bigger batteries for one or two days. If that fails the mission can still be aborted.

« Last Edit: 02/23/2013 08:52 AM by guckyfan »

Offline Dalhousie

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Re: Inspiration Mars Foundation Press Conference
« Reply #198 on: 02/23/2013 08:49 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.
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Offline rklaehn

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Re: Inspiration Mars Foundation Press Conference
« Reply #199 on: 02/23/2013 09:02 AM »

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.

........

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

Not critisizing, just a question. Would two launches really be that much more complex? You propose rearranging the stack after launch anyway and I agree it would be necessary.

It would not be that much more complex. But 2018 is pretty close, so the only way this would make sense would be to reduce the complexity to the bare minimum, which is one launch.

If you have the budget and time for a multiple-launch mission, you can fly a very comfortable tour of the solar system, including a bigelow sundancer and lots of margin. That way you could also do a flyby with one of the less optimal mars launch windows.

There was a long thread about a similar topic a few years ago, with some very detailed calculations regarding launch windows, delta-v and mass requirements. Back then the falcon heavy still had 19 tons to GEO though.

http://forum.nasaspaceflight.com/index.php?topic=15878.0

Edit:
http://forum.nasaspaceflight.com/index.php?topic=15878.msg717396#msg717396

The delta-v for the circumnavigation mission back then was C3=0 + 1000m/s. So this should be the same ballpark.



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.
« Last Edit: 02/23/2013 09:16 AM by rklaehn »
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