Author Topic: Manned Mars Lander  (Read 63529 times)

Offline Hyperion5

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Manned Mars Lander
« on: 11/08/2013 03:41 pm »
Over the years NASA, the private sector and even other governments have commissioned studies of what a manned Mars lander might look like.  The most recent NASA effort thought they would be horizontal landers and operate as they're shown in this video:



As you can see, these landers would feature six descent engines, a disposable heat shield, a disposable aeroshell on their back, four landing legs and would also use a trio of parachutes to slow down.  The crew habitat lander would differ only in having a Mars Ascent Vehicle placed at its center, ready to go upon mission's end.  Recently there's been talk of reusable Mars landers or at the very least of using existing Spacex Dragons to land crew on the Red Planet (see Mars One).  So I thought, why not have a thread where we can debate which of the many Mars lander concepts had it down best?  I put this thread here in Advanced Concepts on meekGee's advice. 

It appears to me that there are really only two basic types of Mars landers:

Horizontal landers: long horizontal cylindrical landers that land on their belly.  These are the type currently favored by NASA. 
Vertical landers: often cone-shaped that vaguely resemble the Apollo LM in landing.  Vertical landers were what NASA originally envisioned for landing on Mars back in the 1960s. 

After this point things we can now divide the landers even further:

Mars direct ascent landers: The lander functions as its own Earth Departure Stage and makes a direct descent to the Martian surface.  Depending on the design, the whole lander may or may not make the ascent back to orbit and then make the burn for Earth.  This design may depend on ISRU to be feasible. 
Mars Orbit Rendezvous landers: The approach the Constellation program envisioned, the lander is docked to a Mars Transfer Vehicle or an EDS.  Once inserted into LMO, the lander detaches, enters Mars atmosphere and lands.  Depending on the design, only part of the lander may return to the MTV or EDS as the Mars Ascent Vehicle". 

Of course, let's not forget one last crucial category:

Reusable Mars landers: A Mars lander that not only can land and ascend on and off Mars, but do it repeatedly and reliably.  There is some talk that Spacex envisions something like this for the future, though it would require some serious heat-shield cooling and probably some ISRU capability. 

Non-reusable Mars landers: The envisioned NASA approach that much like Apollo leaves bits and pieces of defunct lander segments on Mars once the mission's over.  This approach has the advantage of mass savings and performance optimization at the expense of needing new landers for every mission. 


Let people know what approaches you feel are best for such a craft and why.  I am a big proponent of shielded engine ports mounted into the sides of the landers much like Super Dracos will be mounted onto the Dragon, but that's just me.  Tell us why you believe how your envisioned Mars lander would work or at least what things you think any Mars lander ought to have and what it should not. 

« Last Edit: 11/08/2013 04:04 pm by Hyperion5 »

Offline simonbp

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Re: Manned Mars Lander
« Reply #1 on: 11/08/2013 06:35 pm »
One of the traditional bugaboos about designing a Mars lander has been the problem of supersonic retro-propulsion. This is a problem since any reasonable aeroshell has a terminal velocity of several Mach. So you need either supersonic retro-propulsion or heavy parachutes to brake to subsonic first (and then subsonic retro-propulsion). The original Mars Voyager proposals in the 1960s used supersonic retro-propulsion, but JPL couldn't get it to work. So, when a half-size Mars Voyager was resurrected as Viking, a supersonic parachute was added. All subsequent JPL landers/rovers have used this design. I recall Rob Manning giving a presentation to us JPL interns in 2006 saying that supersonic retro-propulsion would be the best thing for Mars EDL, but that noone knew how to get it working.

That was until last month. On the first Falcon 9 v1.1 flight, SpaceX demonstrated supersonic retro-propulsion on the first stage (that was the part of the recovery that actually worked). If SpaceX really have cracked the code on this, then they will be able to land much easier on Mars than any proposals since the Mars Voyager days.

Offline 93143

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Re: Manned Mars Lander
« Reply #2 on: 11/08/2013 07:50 pm »
SpaceX demonstrated supersonic retro-propulsion

What were the atmospheric conditions during the retro burn, vs. the conditions encountered by a Mars lander following the heat shield portion of the deceleration?

Technically, every manned LEO spacecraft since Vostok 1, in addition to the odd unmanned vehicle, has performed supersonic retropropulsion; it's called a deorbit burn.  The conditions matter.
« Last Edit: 11/08/2013 10:01 pm by 93143 »

Offline Dalhousie

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Re: Manned Mars Lander
« Reply #3 on: 11/08/2013 08:07 pm »
Horizontal lander.  It's a much better configuration for use after landing and has many advantages during EDL as well.
Apologies in advance for any lack of civility - it's unintended

Offline M129K

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Re: Manned Mars Lander
« Reply #4 on: 11/08/2013 08:08 pm »
Adding the ESA Mars Excursion Vehicle from the 2004 Overall Architecture Assessment study (IIRC, it's basically a European DRM and will be updated in the future) to the thread. It is very tall and looks unstable, to be honest. It can support the crew of three for 30 days, and carries an inflatable heatshield/aeroshell in space, and uses parachutes and retro propulsion for landing. I like the design for shorter duration missions, but the mission designed around it is just atrocious.

Advantages of a lander like this is that no additional cargo lander is required, no ISRU is required, and both the Hab and MAV are placed there in just one vehicle. With an on-orbit mass of 42 tons, it's reasonable by Mars lander standards, and can do everything needed for shorter stays. However, for longer missions it is obviously flawed. A separate cargo lander could fix most of its flaws though.
« Last Edit: 11/08/2013 08:29 pm by M129K »

Offline Lobo

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Re: Manned Mars Lander
« Reply #5 on: 11/09/2013 12:53 am »
One of the traditional bugaboos about designing a Mars lander has been the problem of supersonic retro-propulsion. This is a problem since any reasonable aeroshell has a terminal velocity of several Mach. So you need either supersonic retro-propulsion or heavy parachutes to brake to subsonic first (and then subsonic retro-propulsion). The original Mars Voyager proposals in the 1960s used supersonic retro-propulsion, but JPL couldn't get it to work. So, when a half-size Mars Voyager was resurrected as Viking, a supersonic parachute was added. All subsequent JPL landers/rovers have used this design. I recall Rob Manning giving a presentation to us JPL interns in 2006 saying that supersonic retro-propulsion would be the best thing for Mars EDL, but that noone knew how to get it working.

That was until last month. On the first Falcon 9 v1.1 flight, SpaceX demonstrated supersonic retro-propulsion on the first stage (that was the part of the recovery that actually worked). If SpaceX really have cracked the code on this, then they will be able to land much easier on Mars than any proposals since the Mars Voyager days.

That's going to be one of the challenges to landing large landers on Mars I think.  I'd heard that payloads about the size of the MSL are about as big as can be done with the existing types of EDL systems, as the parachute becomes too big to deploy reliably or something.  (I remember something like that).  So to go larger, new EDL Systems are needed.  Mostly likely, replacing the parachutes with more retropropulsion for deceleration.

I think there's a couple ways possibly around the issue if firing an engine into the thin Martian supersonic slipstream if that's a problem.

One is to have a big jettisonable aeroshield, with retro engines protected behind it.  When the engines are lit, the shield kicks off and impacts the surface.  That way the engines don't light into a supersonic slipstream.  I would think once they are lit and pressurized, the thin Martian air wouldn't be able to to enger the nozzle and be a problem.  The exhaust plume expelled out the bottom should overpower and basically split the slipstream.

See pics below.

Another is something like RedDragon where the nozzles are tucked back just out of the slipstream and the heatshield creates a bit of a splash efffect in the atmosphere (see picture below as well).  As long as those nozzles are tucked in enough, they shouldn't have supersonic Martian air coming into them I don't think.  I would guess this is the concept behind why RedDragon's superdraco's are expected to work for landing on Mars.
If so, you can scale that up with larger engines.  Perahps bigger methalox enignes in a scaled up geometry of Dragon.  It's not as efficient to have engines positioned like that because of their outward angle.  But it should hopefully be feasibel for landing purposes.  A Mars ascent vehicle of some sort can have engines directly under it for better efficiency for ascent.


Offline Lobo

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Re: Manned Mars Lander
« Reply #6 on: 11/09/2013 01:35 am »
So, maybe we can start the discussion with the minimalist approach. 

We'll start with something SpaceX-y and hypothetical, as they are least seem to be putting forth some effort to getting to Mars.
Assume for the same of this post, that SpaceX makes a new LV they call FalconX.  They make it a scaled up Falcon9.  They put nine 611klbf metholox engines on the booster, and one on the upper stage.  Maybe that puts around 90mt to LEO.
Maybe a tri-core heavy with crossfeed can put 300mt to LEO.  (for the sake of this example).
So we have a lot of capacity.  I think for a very efficient system, TMI capacity is about 1/3 of LEO.  The new Boeing numbers for SLS Block 1B reflect that.  But this LV will be methalox not hydrolox, so instead of throwing 100mt through TMI, we'll say maybe 85mt, for this example.

So how simple and/or reusable could we make this?

How about a scaled up Dragon capsule  Call it SuperRedDragon (SRD).  It's thrown to TMI, it directly desceds through EDL, and lands on poweful methalox Raptor engines of some type.  It lands empty but has a tank of LH2 to make enough methalox to ascend and burn directly for TEI.  Back at Earth, the SRD heads directly to earth EDL, and lands with is residual propellants as Dragon will.  It'll be much lighter on the way home as several tonnes of equipment and consumables will be left behind.   It'll be an empty shell with a hab unit on top.

This would be similar to Zubrin's Mars Direct, but where Zubrin pictured using a 130mt Ares SDHLV, and does it in two launches, this would have a boosters more than twice that powerful, and could -maybe- do it in just one launch. 

Now, this could be economically efficient, but it won't be mass efficient.  So it won't a lot of landed mass of equipment.  I think we'd be happy if it could just get itself down, and back to earth, with a few tonnes worth of small rovers, experiments, and such. 
And while engines angled out like Dragon's would be ok for descent and landing on both Mars and Earth, they take a big performance hit for ascent and TEI.  So I think such a SRD would need some sort of engine nozzles which are stowed like Superdracos for descent, but could extend and rotate down for ascent and TEI.  Then retract back to the stowed position for EDL at Earth, so they'd be protected during Earth reentry.   That'd be a technological hurdle, but I don't know if it'd be a deal breaker.  It wouldn't need to extend or retract during descent or ascent, only on the surface, and then retract some time between TEI and Earth EDL.  I think if that could be engineerd, it could improve the odds of this all-purpose vehicle working.

Again, it sounds a bit optimistic, but Zubrin thought something like that but one a smaller scale would work for the ERV. 
An unmanned one could be sent first.  Then the next crewed ones are within a rover distace of it, so it could be used as a backup.  I picture a big Dragon, with a hab area on top, and tall cylinderical fuel tanks in the middle.  Then a donut shaped equipment deck around it under the hab area with a door that opens downward and makes a ramp.  Like the picture below, but the door opens down rather than sideways, and there'd not be a truck there unloading.  The cargo would be rolled down the ramp to the surface.
O2 could be mined from the CO2 in the atmosphere, and most water would be recycled like on the ISS.  A Sabatier reactor combines the LH2 with atmospheric CO2 to make Methalox for fuel.
A few similar concept pics below.  The question is, could a single vehicle like this do everything and get all the way back to Earth?  If so, maybe now you have Elon's hinted at reusable MCT?  The tri-core FXH would at least have reusable boosters, even if the core and upper stage are expended.
On Earth, it can be refurbished and launched again.   (although after a mission like that, I'd be pretty surprised if they actually reused the thing).

If FX has a core of say 7m wide, you -should- be able to get maybe a 12m SRD/PLF on it.  Maybe 14m.  Would be a lot of wind tunnel testing on going that much wider than the core, obivously.  So if there was a 14m wide SRD, that should be a pretty good sized lander.  I think Zubrin's landers were in his Ares booster PLF which was 10 I think.  And they seemed pretty big, and this would be even bigger than those.   
For a colony, you have an expendable variant that doesn't have the LH2 tank, no hab area on top, and just lands unmanned with as much equipment as it can carry to support the crews already on site. 

It's a starting point anyway.  As Hyperion pointed out, there's lots and lots of ways to go with it. 
« Last Edit: 11/09/2013 01:48 am by Lobo »

Offline Hyperion5

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Re: Manned Mars Lander
« Reply #7 on: 11/09/2013 01:58 am »
I'd heard that payloads about the size of the MSL are about as big as can be done with the existing types of EDL systems, as the parachute becomes too big to deploy reliably or something.  (I remember something like that).  So to go larger, new EDL Systems are needed.  Mostly likely, replacing the parachutes with more retropropulsion for deceleration.

See the 2:40 mark of the video in the first post.  The lander, which clearly masses considerably more than the Apollo Lunar Module, is deploying not one but 3 parachutes.  These deploy after the back aeroshell is left behind, allowing the parachutes to unfurl.  As the parachutes unfurl the descent engines kick in.  I believe Steven Pietrobon mentioned that this approach chops the descent delta-v required from the engines to a mere 500 m/s.  That's an impressively low figure for landing something 50 mt or more on Mars.  I don't know what the figure would be doing an all-propulsive approach, but it'll be significantly more than that. 

I think there's a couple ways possibly around the issue if firing an engine into the thin Martian supersonic slipstream if that's a problem.

One is to have a big jettisonable aeroshield, with retro engines protected behind it.  When the engines are lit, the shield kicks off and impacts the surface.  That way the engines don't light into a supersonic slipstream.  I would think once they are lit and pressurized, the thin Martian air wouldn't be able to to enger the nozzle and be a problem.  The exhaust plume expelled out the bottom should overpower and basically split the slipstream.

Again, I reference the video.  It appears that NASA envisioned its Constellation landers having a big jettisonable aeroshield with retro descent engines protected behind it.  It's when the parachutes fully deploy that the bottom aeroshield/heat shield drops off and the engines fire up.  If ignition in these conditions were a large problem, I would not expect NASA to have dedicated the time and resources to create a video detailing how they'd land on Mars using Ares-launched payloads. 

Another is something like RedDragon where the nozzles are tucked back just out of the slipstream and the heatshield creates a bit of a splash efffect in the atmosphere (see picture below as well).  As long as those nozzles are tucked in enough, they shouldn't have supersonic Martian air coming into them I don't think.  I would guess this is the concept behind why RedDragon's superdraco's are expected to work for landing on Mars.

If so, you can scale that up with larger engines.  Perahps bigger methalox enignes in a scaled up geometry of Dragon.  It's not as efficient to have engines positioned like that because of their outward angle.  But it should hopefully be feasibel for landing purposes.  A Mars ascent vehicle of some sort can have engines directly under it for better efficiency for ascent.

I'm curious, but are all the Mars landers you envision Mars Orbit Rendezvous types or would you ever consider a direct ascent lander?  I ask because the rough estimates are that a 9-Raptor per core Falcon X Heavy would fling more than 110 mt through TMI.  It's so much mass you could feasibly pull it off.  Of course the problem I see is getting back off of Mars. 

http://www.angelfire.com/md/dmdventures/orbitalmech/DeltaV.htm

From   To   Delta-V (km/s)
LEO   Mars Surface   4.8
LEO   Lunar surface   6.2
Mars   LMO   4.4
LMO   Mars    0.05
LMO   Earth return   3.4
Lunar surface LEO 3.2


Total delta-v required

To Mars surface and back to Earth: 22 km/s (12.6 km/s required for everything beyond LEO)
To lunar surface and back to Earth 18.8 km/s (9.4 km/s required for everything beyond LEO)


It seems pretty clear from the math that Spacex or anyone else for that matter would be hard-pressed to pull off a Mars direct ascent approach.  It'd work superbly if all they cared about was getting payloads to the surface of Mars though.  Matter of fact, it requires only 77.4% of the delta-v needed (beyond LEO) to land on the Moon for you to land on Mars.  Now if only there wasn't that dire fact about half of all missions to Mars ending in failure adding a huge asterisk to that.  My guess is if that if anyone wants to mount a round-trip mission, pretty much all the landers will have to be Mars orbit rendezvous types.  Otherwise you're adding a lot of unnecessary propellant and structural mass to the mission that could otherwise be put into useful cargo and habitat mass. 


Offline Hyperion5

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Re: Manned Mars Lander
« Reply #8 on: 11/09/2013 02:11 am »
Horizontal lander.  It's a much better configuration for use after landing and has many advantages during EDL as well.

Steven Pietrobon was just as adamantly telling me a few months ago that any Mars lander should be vertical because it simplifies the design.  Could you please list the advantages you believe or know that a horizontal lander would have besides for use after landing? 

Offline go4mars

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Re: Manned Mars Lander
« Reply #9 on: 11/09/2013 02:14 am »
I still like the idea of deep throttling landers, so that they can reusably stack and stage for ascent from Mars (trans-earth inj).  Whether parallel staged or otherwise, lower stages return to Mars, top one heads to Earth.  But I think that's just me who likes that idea.  All I've ever heard back on that idea is crickets.
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Offline Lars_J

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Re: Manned Mars Lander
« Reply #10 on: 11/09/2013 04:16 am »
I think a horizontal lander would indeed be superior if you wanted to land the maximum amount of cargo one-way, and have it easily accessible to unload.

BUT - if you want a reusable lander that will do ascent as well, that pretty much requires a vertical deep throttling lander.  IMO.

Offline M129K

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Re: Manned Mars Lander
« Reply #11 on: 11/09/2013 07:58 am »
Horizontal lander.  It's a much better configuration for use after landing and has many advantages during EDL as well.
ESA evaluated both options, they picked a vertical lander. It's probably not as obvious as you think.

Offline Oli

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Re: Manned Mars Lander
« Reply #12 on: 11/09/2013 12:32 pm »
A few documents.

The Challenge for Mars EDL (presentation):
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100017668_2010017622.pdf

Mars Exploration Entry, Descent and Landing Challenges (paper):
http://www.ssdl.gatech.edu/papers/conferencePapers/IEEE-2006-0076.pdf

Fully-Propulsive Mars Atmospheric Transit Strategies for
High-Mass Payload Missions
(paper):
http://www.ssdl.gatech.edu/papers/conferencePapers/IEEE-2009-1219.pdf


------------------------------------------------------------------------------------------


The problem with capsules is that you'd need huge diameters. The MSL had already a 4.5m diameter heat shield.

You could go full-propulsive but in that case the payload mass fraction is rather pathetic. In the paper above the baseline vehicle is 60t in low Mars orbit, of which 8.7t are payload delivered to the surface. Of course those 60t need to be transported from LEO to LMO, which brings total LEO departure mass to around 350t (ISP of 350s).

« Last Edit: 11/09/2013 02:18 pm by Oli »

Online guckyfan

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Re: Manned Mars Lander
« Reply #13 on: 11/09/2013 02:44 pm »
The problem with capsules is that you'd need huge diameters. The MSL had already a 4.5m diameter heat shield.

You could go full-propulsive but in that case the payload mass fraction is rather pathetic. In the paper above the baseline vehicle is 60t in low Mars orbit, of which 8.7t are payload delivered to the surface. Of course those 60t need to be transported from LEO to LMO, which brings total LEO departure mass to around 350t (ISP of 350s).

Don't go int LMO, go in directly like MSL did. Brake with your heatshield as far as the diameter allows and then do a propulsive landing.

Offline Oli

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Re: Manned Mars Lander
« Reply #14 on: 11/09/2013 03:16 pm »
^

I just wanted to delete my previous comment. Full-propulsive in this case means no significant heatshield requirement, but IMO its kind of pointless.

For example the Austere Human Mission to Mars uses 13m diameter landers with ~53t payload:

http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41431/1/09-3642.pdf

A combination of heatshield and retropropulsion.
« Last Edit: 11/09/2013 03:17 pm by Oli »

Offline Rocket Science

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Re: Manned Mars Lander
« Reply #15 on: 11/09/2013 04:05 pm »
Could we please have the links for these images?
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Offline Hyperion5

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Re: Manned Mars Lander
« Reply #16 on: 11/09/2013 04:18 pm »
A few documents.

The Challenge for Mars EDL (presentation):
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100017668_2010017622.pdf

Mars Exploration Entry, Descent and Landing Challenges (paper):
http://www.ssdl.gatech.edu/papers/conferencePapers/IEEE-2006-0076.pdf

Fully-Propulsive Mars Atmospheric Transit Strategies for
High-Mass Payload Missions
(paper):
http://www.ssdl.gatech.edu/papers/conferencePapers/IEEE-2009-1219.pdf


------------------------------------------------------------------------------------------


The problem with capsules is that you'd need huge diameters. The MSL had already a 4.5m diameter heat shield.

You could go full-propulsive but in that case the payload mass fraction is rather pathetic. In the paper above the baseline vehicle is 60t in low Mars orbit, of which 8.7t are payload delivered to the surface. Of course those 60t need to be transported from LEO to LMO, which brings total LEO departure mass to around 350t (ISP of 350s).

In one of the papers you posted the payload mass fraction with 1000 second Isp NTRs was an astoundingly bad 8.7%.  I believe that was for full retro-propulsion from mach 3 without aeroassist or parachutes.  The other papers were giving far lower propellant mass fractions as well of around .3-.2, compared to .6-.4.  The part that most impressed me was that larger landers required less delta-v to land and consequently had lower propellant mass fractions. 

Since it makes the math easy to follow, how would a 100 t Constellation-style lander fare in landing mass on Mars?  Let's say it has descent engines with 380 seconds of Isp.  According to this paper (http://www.ssdl.gatech.edu/papers/conferencePapers/IEEE-2006-0076.pdf) the resulting propellant mass fraction then ought to be around .24.  This is roughly similar to the propellant mass fraction of airliners.  Could we then reasonably expect such a lander to land payloads similar in proportion to airliners?  If so, I would expect the max payload to mass around 30 tonnes.  If not, then how much payload should we expect to land on Mars with such a vehicle? 

Offline spectre9

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Re: Manned Mars Lander
« Reply #17 on: 11/10/2013 12:58 am »
SRP is the next big challenge.



I like seeing what happens to the flow.

Offline Lobo

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Re: Manned Mars Lander
« Reply #18 on: 11/10/2013 04:58 am »
^

I just wanted to delete my previous comment. Full-propulsive in this case means no significant heatshield requirement, but IMO its kind of pointless.

For example the Austere Human Mission to Mars uses 13m diameter landers with ~53t payload:

http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41431/1/09-3642.pdf

A combination of heatshield and retropropulsion.


Ahhhh.....

Yes, this is a little more like what I had in mind.  Except the lander has deployable rockets that much be deployed during EDL.  With a shape like Dragon having less sidewall angle, SpaceX seems to feel confident that the engines can be fixed and still do the retro propulsion to land.  And that saves having to have a mechanism that needs to actuate during such a stressful time on the craft. If one engine were to not deploy right, the lander is a smoking crater.

However, if it lands like Dragon, then the engines could still deploy out and down around the edges of the heat shield so that they are pointed directly down for ascent and then TEI burn for greater efficiency. 
Then the engines would be deployed on the ground while the lander is at rest, rather than during EDL.  The astronauts could assist them in some manual way if there were any issues. 
And then after TEI, they would be retracted prior to EDL on Earth.  Again, not during the stresses of EDL.  And if there was an issue with retracting them, well they have a long ride home to get the issue resolved. 

But...a point here is that NASA seemed to think it feasible at some level for a lander to have engines that actuate out and deploy and then light into the slipstream.  So maybe it's not too big of a deal?




Offline Lobo

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Re: Manned Mars Lander
« Reply #19 on: 11/10/2013 05:17 am »

See the 2:40 mark of the video in the first post.  The lander, which clearly masses considerably more than the Apollo Lunar Module, is deploying not one but 3 parachutes.  These deploy after the back aeroshell is left behind, allowing the parachutes to unfurl.  As the parachutes unfurl the descent engines kick in.  I believe Steven Pietrobon mentioned that this approach chops the descent delta-v required from the engines to a mere 500 m/s.  That's an impressively low figure for landing something 50 mt or more on Mars.  I don't know what the figure would be doing an all-propulsive approach, but it'll be significantly more than that. 


PAge 19 of this document talks about this.

Mars Exploration Entry, Descent and Landing Challenges (paper):
http://www.ssdl.gatech.edu/papers/conferencePapers/IEEE-2006-0076.pdf


"Supersonic propulsive descent
Following hypersonic entry, a vehicle intending to land on
the surface of Mars must slow itself from supersonic
velocities to a speed appropriate for a soft landing. This last
deceleration phase, which involves only a few percent of the
vehicle’s remaining kinetic energy, has been initiated in past
robotic missions below Mach 2.1 using some combination
of parachutes and rocket-propelled descent. From Figure 20,
it is clear that a Mach 2 initiation of this phase is not
sufficient for the high mass entry systems associated with
human exploration. The total descent time from Mach 3 or 4
to landing is on the order of two minutes. During this phase,
several vehicle configuration changes are required. In a
matter of seconds, the vehicle will need to re-orient itself, an
aeroshell and/or back shell may be jettisoned, parachutes
may deploy, engines may start, navigation and hazard
avoidance sensors must operate, and landing gear may
deploy. In this very dynamic phase of flight, robust event
sequencing and timeline margin are critically important.
To date all parachutes utilized in the robotic Mars
exploration program have been derived from the technology
effort that led to the Viking flight project. These systems
have been limited to diameters on the order of 10-20 m and
supersonic deployments below Mach 2.1. As discussed in
Section 5, in an effort to improve landed mass, the robotic
exploration program may pursue a large diameter supersonic
parachute, likely no larger than 30 meters and deployed at
velocities below Mach 2.7 (in response to thermal
constraints). As a result of the large masses involved,
parachutes sized for human exploration systems would
represent a significant departure (in both size and
deployment Mach number) from their robotic counterparts.
In addition, due to their size, such systems will require
significant opening times. For example, to decelerate a 100 t
vehicle from Mach 3 conditions to 50 m/s near the Mars
surface would require a supersonic parachute diameter on
the order of 130 m. Similarly, a 50 t vehicle requires a
supersonic parachute diameter on the order of 90 m. While
clustered supersonic chutes are an option, the size of such
systems would still result in large timeline penalties for
opening. As such, an all parachute approach for Mars
human exploration vehicles, similar to the concepts now
used for robotic landers, is likely impractical."


It was something like this that I was thinking of.  I guess it's not so much the parachutes can't be made big enough, but that they might take too long to deploy.

It continues with some more info:


"While parachutes alone are inadequate for slowing large
payloads at Mars, the all-propulsive solution results in high
propellant mass fractions and requires aeroshell separation
and propulsive descent initiation to take place at supersonic
speeds. As such, a trade study was conducted to quantify
how a large, supersonic parachute could mitigate these
issues. In this assessment, aggressive assumptions were
made in regard to parachute deployment conditions
(Mach 3) and altitude requirements for the subsequent
descent and landing events. Figure 24 shows the parachute
sizes required to decelerate a payload from Mach 3 to Mach
0.8 at an altitude of 2 km. A Mach number of 0.8 was
chosen to mitigate the aeroshell separation and re-contact
concerns of current robotic landers. Figure 24 shows that a
30 m, Mach 3 parachute allows for a subsonic propulsive
deceleration maneuver if entry masses are below
approximately 33 t. This same parachute can slow the
vehicle to Mach 1.0 at 2 km for entry masses less than 50 t.
For entry masses above 50 t, a larger chute is required (with
a significant opening time penalty), or the propulsive
deceleration maneuver must begin supersonically.
An additional benefit of this approach is that the parachute
can be used to separate the payload from the aeroshell.
Atmospheric uncertainty is a major driver for parachute assisted
descent. The results described above are for a
nominal atmosphere. If a conservative density is modeled,
the 30 m parachute is only practical for entry masses below
approximately 20 t. Parachute assisted propulsive descent
still requires significant propellant mass fraction to bring the
vehicle from Mach 0.8 to a soft landing. The propellant
mass fraction required for just the cross range maneuver (to
protect pre-landed assets on the surface) will actually
increase for a parachute-assisted system because the burn is
started much later in the descent. Overall, the total
propellant mass fraction required for descent and landing
will decrease from 20-30% of entry mass for an all propulsive
system (see Fig. 23), to a range of 12-18% for a
parachute assisted system.'


However, where this whole equation changes, is they are trying to maximize landed mass, understandably.  And this lander is probably not trying to get back of the ground.  However, any vehicle that needs to get back to Mars orbit, or do a directly return from the surface, will need a LOT of propellant.  with large tanks for that propellant.  So if you are designing to maximize usage of components and minimize elements rather than maximize landed mass, then it could be ok that there's a large dV penalty for propulsive supersonic retropropulsion.  The lander would have the fuel tank capacity as it needs much more than that to get back to Earth.  It lands burning up it's stored methalox, and then refuels on the surface with it's LH2 store.  Then lifts itself back off the surface.  And burns for Earth.  Or rendezvous with a MTV and is discarded. 

Such a lander would probably not be able to land very much cargo on the surface, but if it could actually work, it would maximize element use, and minimize individual elements.  A simple system with minimal elements, but not perhaps very efficient in the amount of equipment it can drop off on the surface. 
In a single new vehicle development, you have your Mars Transit Hab, your lander, your Mars Ascent Vehicle, and your Earth Return Vehicle.  And you get to land it all back on Earth.  The side advantage is this can probably take off form Mars and land on Earth with a decent amount of Mars samples compared to a more traditional architecture that only lands say, an Orion Capsule back on Earth.



« Last Edit: 11/10/2013 05:41 am by Lobo »

Offline Lobo

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Re: Manned Mars Lander
« Reply #20 on: 11/10/2013 06:14 am »

I'm curious, but are all the Mars landers you envision Mars Orbit Rendezvous types or would you ever consider a direct ascent lander?  I ask because the rough estimates are that a 9-Raptor per core Falcon X Heavy would fling more than 110 mt through TMI.  It's so much mass you could feasibly pull it off.  Of course the problem I see is getting back off of Mars. 


Hmmm?
This whole concept I'm kicking around is a direct ascent lander.  And a Direct landing landing lander. 
Mars Direct, but with both of Zubrin's landers combined into a single bigger lander.  A double sized version of Zubrin's ERV basically.  Zubrin was working with a SDHLV with a much smaller capacity than FXH might have.  So putting everyone in the ERV and sending them to Mars in a single vehicle would make things pretty cramped for the trip out and the surface stay.  Zubrin only had them in it for the trip home.  Plus it would land with very little equipment and provisions.  But...with the potential of a an LV in the 200-300mt range (our speculation) Than that ERV and be scaled up.  A Larger hab capable of adequately sustaining the crew for the trip out and the surface stay as well as the trip home.  Enough cargo room for at least some modest equipment for the surface mission.  Some small rovers, solar arrays, and inflatable surface habs, etc. 


http://www.angelfire.com/md/dmdventures/orbitalmech/DeltaV.htm

From   To   Delta-V (km/s)
LEO   Mars Surface   4.8
LEO   Lunar surface   6.2
Mars   LMO   4.4
LMO   Mars    0.05
LMO   Earth return   3.4
Lunar surface LEO 3.2


Total delta-v required

To Mars surface and back to Earth: 22 km/s (12.6 km/s required for everything beyond LEO)
To lunar surface and back to Earth 18.8 km/s (9.4 km/s required for everything beyond LEO)


It seems pretty clear from the math that Spacex or anyone else for that matter would be hard-pressed to pull off a Mars direct ascent approach.  It'd work superbly if all they cared about was getting payloads to the surface of Mars though.  Matter of fact, it requires only 77.4% of the delta-v needed (beyond LEO) to land on the Moon for you to land on Mars.  Now if only there wasn't that dire fact about half of all missions to Mars ending in failure adding a huge asterisk to that.  My guess is if that if anyone wants to mount a round-trip mission, pretty much all the landers will have to be Mars orbit rendezvous types.  Otherwise you're adding a lot of unnecessary propellant and structural mass to the mission that could otherwise be put into useful cargo and habitat mass.

You could have a variant of this lander that was a cargo hauler.  Remove the hab area to lighten it up for more cargo mass.  And remove the mass of the LH2 and it's tank as this lander won't be lifting off again, so no need to generate more fuel on the surface.  Everything about EDL would be the same, and the same launch mass and landed mass.  But you are trading extra vehicle mass for cargo mass.

At the end of the day, you are probably right...  The penalties are probably too big to be able to have a single common vehicle that can land on mars, take off again, come back to Earth and then land on earth. 
Be pretty cool if could though.

You might still be able to have something like this with MOR.  Like in the paper Oli posted, the DAV.  The Descent Ascent Vehicle.  If it's not coming back to Earth it can have a jettionsable heat shield so it doesn't have to bring it back up.  The engines could be fixed behind it, pointing straight down.
And do a more Mars Semi-Direct type of architecture.

Offline Hyperion5

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Re: Manned Mars Lander
« Reply #21 on: 11/10/2013 07:59 am »

See the 2:40 mark of the video in the first post.  The lander, which clearly masses considerably more than the Apollo Lunar Module, is deploying not one but 3 parachutes.  These deploy after the back aeroshell is left behind, allowing the parachutes to unfurl.  As the parachutes unfurl the descent engines kick in.  I believe Steven Pietrobon mentioned that this approach chops the descent delta-v required from the engines to a mere 500 m/s.  That's an impressively low figure for landing something 50 mt or more on Mars.  I don't know what the figure would be doing an all-propulsive approach, but it'll be significantly more than that. 


PAge 19 of this document talks about this.

Mars Exploration Entry, Descent and Landing Challenges (paper):
http://www.ssdl.gatech.edu/papers/conferencePapers/IEEE-2006-0076.pdf


 Similarly, a 50 t vehicle requires a
supersonic parachute diameter on the order of 90 m. While
clustered supersonic chutes are an option, the size of such
systems would still result in large timeline penalties for
opening. As such, an all parachute approach for Mars
human exploration vehicles, similar to the concepts now
used for robotic landers, is likely impractical."


I believe the 4.8 km/s of delta-v that site factored in included some 400 m/s of retro-propulsion into it.  If you look at the video of the Constellation lander, I think they're doing more than 50 m/s of retro-propulsion.  If you upped that to say 400 m/s and let the parachute(s) and aeroshell/heat shield take care of the rest it should work.  I don't believe even Curiosity got down to 50 m/s when it fired up its retro-rockets.  It was going at least 80 m/s at just around 2 km up when those fired.  So it'd be more of a challenge to fire those up earlier, but I think 300-400 m/s of delta-v from the retro-propulsion is very reasonable.  Particularly when the alternative is a full 1000 m/s delta-v for a landing done only with retro-propulsion. 

Offline Lobo

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Re: Manned Mars Lander
« Reply #22 on: 11/11/2013 05:31 pm »

I believe the 4.8 km/s of delta-v that site factored in included some 400 m/s of retro-propulsion into it.  If you look at the video of the Constellation lander, I think they're doing more than 50 m/s of retro-propulsion.  If you upped that to say 400 m/s and let the parachute(s) and aeroshell/heat shield take care of the rest it should work.  I don't believe even Curiosity got down to 50 m/s when it fired up its retro-rockets.  It was going at least 80 m/s at just around 2 km up when those fired.  So it'd be more of a challenge to fire those up earlier, but I think 300-400 m/s of delta-v from the retro-propulsion is very reasonable.  Particularly when the alternative is a full 1000 m/s delta-v for a landing done only with retro-propulsion.

Perhaps a better way to approach it is more like the biconic shapes that have been the favorite for NASA DRM's, as well as Zubrin's Mars Direct for the ERV.

Something like the DC-X/Y.  Then your engines are fixed downward without the need to deploy anything, other than landing legs.  Might be better to have tall, more slender propellant tanks running through the center of the vehicle though, rather than just two tank on top of each other. IN this way, your center of gravity is all at the bottom when doing terminal descent, rather than having the mass of the LOX or CH4 up the bottom of a higher tank.  Kind of like how Boeing's Lunar and Mars methalox lander had slender vertical tanks.  Then you could have your cargo deck down low around the tank cluster in the center, so that they are near the surface for ease of deployment. 

It does present some challenges of reorientation in a supersonic slipstream to get the engines down and then get them lit.  I think the blunt body like the SuperRedDragon is a safer design in certain respects. (No supersonic orientation, no firing of rockets into a supersonic slip stream, not as tall) But it might just not be feasible to make that shape do everything.  (it might not be feasible to make -any- shape do everything actually).

Edit:  I Borrowed the picture that Lars Posted here for this.  Different tread but it made me look at it for a Mars lander.

http://forum.nasaspaceflight.com/index.php?topic=32180.msg1118725#msg1118725
« Last Edit: 11/11/2013 10:03 pm by Lobo »

Online MickQ

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Re: Manned Mars Lander
« Reply #23 on: 11/12/2013 08:59 am »
Do the engines have to be at or near the bottom of the lander ?

What if they were on aerodynamic pylons at the top of the vehicle and therefore above most of the mass so the lander effectively hangs below instead of sitting on the landing engines ?  A variant on the Skycrane idea .

Mick.

Offline Hyperion5

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Re: Manned Mars Lander
« Reply #24 on: 11/15/2013 02:14 am »
Do the engines have to be at or near the bottom of the lander ?

What if they were on aerodynamic pylons at the top of the vehicle and therefore above most of the mass so the lander effectively hangs below instead of sitting on the landing engines ?  A variant on the Skycrane idea .

Mick.

Well that's a possibility.  Lobo and I have mentioned this possibility to Steven Pietrobon, who keeps pointing out these thrusters being angled out will cut their efficiency and thus the lander's payload mass.  However, if we're dealing with expendable landers, the delta-v needed to land really isn't that high.  Even an all-propulsive landing of a large 100 t lander requires only about a 1000 m/s.  Add some parachutes and you can easily cut that to 400 m/s, and 200 m/s if you want to up landed mass even more.  I'm not sure of the merits of top-mounted versus side-mounted thrusters, but they should be better at preventing debris damaging the landers during the last phase of the descent.  For this reason I prefer descent engines be on the sides or up top and angled out.  It might cost some efficiency but it does help with safety.  Safety for me is the top priority in any Mars landing. 

Offline Elmar Moelzer

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Re: Manned Mars Lander
« Reply #25 on: 11/15/2013 04:56 pm »
Do the engines have to be at or near the bottom of the lander ?

What if they were on aerodynamic pylons at the top of the vehicle and therefore above most of the mass so the lander effectively hangs below instead of sitting on the landing engines ?  A variant on the Skycrane idea .

Mick.
Maybe an aerospike/plug like arrangement as they had envisioned for the ATV VTOL?

Offline docmordrid

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Re: Manned Mars Lander
« Reply #26 on: 11/18/2013 01:43 am »
Jeff Foust tweeting from the "The Path toward Humans to Mars" presser.

Quote
Jeff Foust ‏@jeff_foust
Mike Gazarik: interested in supersonic retropropulsion for Mars EDL; talking with SpaceX about what they did on F9 1st stage recovery.
DM

Online MickQ

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Re: Manned Mars Lander
« Reply #27 on: 11/18/2013 07:23 am »
Do the engines have to be at or near the bottom of the lander ?

What if they were on aerodynamic pylons at the top of the vehicle and therefore above most of the mass so the lander effectively hangs below instead of sitting on the landing engines ?  A variant on the Skycrane idea .

Mick.

Well that's a possibility.  Lobo and I have mentioned this possibility to Steven Pietrobon, who keeps pointing out these thrusters being angled out will cut their efficiency and thus the lander's payload mass.  However, if we're dealing with expendable landers, the delta-v needed to land really isn't that high.  Even an all-propulsive landing of a large 100 t lander requires only about a 1000 m/s.  Add some parachutes and you can easily cut that to 400 m/s, and 200 m/s if you want to up landed mass even more.  I'm not sure of the merits of top-mounted versus side-mounted thrusters, but they should be better at preventing debris damaging the landers during the last phase of the descent.  For this reason I prefer descent engines be on the sides or up top and angled out.  It might cost some efficiency but it does help with safety.  Safety for me is the top priority in any Mars landing.

My thinking is that you have the engines mounted on the MAV which sits atop what is effectively just a cargo container with a heat shield.  The MAV has all the propulsion, descent/ascent engines and OMS in modules mounted on pylons above the majority of the mass of the descending craft so gravity helps with stability.  Gimbal and/or throttle the engines for orientation and steering. Maybe flaps on the pylons could help here as we'll.

Having the engines 5, 6 or more meters above the ground would, as H5 says, reduce or eliminate blown debris damage to the cargo section.  When ready to leave, the MAV lifts off the top leaving the lower cargo unit un-damaged by rocket plumes.  This way the MAV section could be refuelled in orbit and re-used.

I'm just not sure if the MAV should house all the tankage or if descent prop should be carried in the lower section.

Thoughts ?

Mick.

Online MickQ

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Re: Manned Mars Lander
« Reply #28 on: 11/20/2013 07:49 am »
Liken the lander to a Skycrane helicopter, minus rotating parts.  The helo can operate by itself or it can carry cargo containers, vehicles or equipment underslung.

The lander would be the same.  It would contain the crewed area, all propulsion, tankage, avionics and life support.  It could be used solely as a crew transport or as a cargo lander.  I cannot remember who suggested this idea on another thread but if ISRU is available then the lander can fill up on the surface and launch with all the ascent and descent prop required for the next cycle.

Cargo can be hab, power station, ISRU plant, rovers, MPLM type containers, anything that could be made in, or fitted into the same shape and mass limits.

Mick.

Offline MikeAtkinson

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Re: Manned Mars Lander
« Reply #29 on: 11/20/2013 08:09 am »
LMO   Earth return   3.4

Should be:

LMO   Earth return   2.3

assuming aero-braking into LEO (or direct landing), see http://en.wikipedia.org/wiki/Delta-v_budget.

Offline adrianwyard

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Re: Manned Mars Lander
« Reply #30 on: 11/27/2013 10:17 pm »
Why is Heavy EDL on Mars so hard?

The following is an attempt to wrap my head around why high-mass EDL is so difficult on Mars - it leads me to some out-of-the-box ideas, There’s a good chance I’m making some false assumptions, and would appreciate any corrections and/or feedback!

The Main Challenges:

1] At high speed (orbital/interplanetary), the Martian atmosphere is thick enough to cause significant heating.
2] At low speed, it’s not thick enough to provide significant drag or lift. (~1% of Earth sea level)
3] Gravity is 1/3 of Earth, so free-fall acceleration is quite high.
4] Parachutes are problematic for several reasons:
4a] Unlike Earth-based chutes they need to be deployed supersonically because the craft is still going that fast when close to the ground.
4b] Large diameter supersonic parachutes are untested beyond Viking-scale. Deployment times and inflation dynamics of large chutes in a supersonic airstream are big risk factors.

So it seems from an EDL point of view Mars is the worst of all worlds.

While parachutes are problematic deployable rigid aerosurfaces might be of use at high-speeds - when large supersonic parachutes are risky. It seems there should be a period where the dynamic-pressure and heating have lessened to the point that rigid surfaces can be deployed, and yet the pressure is high enough that they'd provide significant lift and/or cross-range. Like a parachute, ballute, or hypercone, they lessen the ballistic coefficient of the system, and the additional lift/drag can be used to burn off groundspeed.

See below for a depiction of one application of this idea (Fig 1: Biconic-Fins). I’ve taken the 10m x 30m biconic aeroshell from DRA 5.0, flattened the bottom windward surface, and added two small long fins. I’m assuming that the initial entry heating will be too high for the fins and so they are initially stowed, hidden in the shock wake. (Fig 2: Fins-Stowed ).

At high speed, once the fins are deployed, this may well ‘fly’ as a lifting body (Fig 3: Fins-Horizontal). Control surfaces on the trailing edges of the fins could be used for directional control (a la ESA’s IXV), but as speed drops, it would need to flare to an ever more extreme pitch angle. This is fine as the goal is to lose ground speed. Also, the momentum of the vehicle in relation to the thin air should allow for control to be maintained.

At lower speeds, I wonder if it would be beneficial to angle the fins down to trap the thinning air, acting a little like a rigid parachute (remember the nose is pointing upwards, but the heat shield on the bottom of the vehicle is facing 'down' with respect to the airstream). (Fig 4: Rigid-Chute)

At some point the vehicle stalls when near vertical (hopefully with a lowish ground speed and near the surface) and it’s time to eject the upper fairing, and release the lander, which nulls the remaining sideways velocity and performs a propulsive landing.

Of course, the fins and changes to the aeroshell add mass, but depicted on the pad it looks relatively slight (Fig 5: On-Pad). The question is if they offer any net benefit in terms of final descent rate and groundspeed when the lander deploys.

If there is any net benefit to adding the mass of these aerosurfaces, then we can play with a couple of variables: the fins can be made larger, and more radically, the aeroshell can be extended down the length of the exterior of the Earth Departure Stage, forming what is essentially a sail. (Fig 6: Larger-Fins, Fig 7: Stretched-Over-EDS.)

Issues and Questions:
1] Do the fins need to be deployed at all? Can they be fixed, and survive the max heating?
2] If not, how are the fins deployed? If skip entry is used, it could be done during the skip, or the vehicle oriented nose-forward temporarily to lessen the forces.
3] RCS: It’s a good guess the DRA 5.0 aeroshell had a beefy RCS. That will be needed here too.
4] Q: How was the biconic aeroshell in DRA 5.0 supposed to be steered? Just RCS?
5] Center of mass will need to be controlled, and strong roll authority required to prevent it rolling onto its side or back - as was the case with DRA 5.0 design. The fins will automatically correct the orientation when in a skyward pointing dihedral configuration, but not when at the anhedral 'parachute' angle. The elevons on the fin trailing edges would be needed in this case.

My goal is to determine if there is any 'low hanging fruit' to be had in terms of tacking on small aerosurfaces to existing designs, with minimal additional mass and complexity. If there is some benefit to be had, then it may be better to design low density lifting bodies from scratch.

To be clear, there’s no mathematical modeling behind any of this, just basic physics knowledge and intuition. I welcome any comments.
« Last Edit: 04/10/2014 12:18 am by adrianwyard »

Offline adrianwyard

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Re: Manned Mars Lander
« Reply #31 on: 11/28/2013 01:18 am »
I just found the following very interesting paper from 2009. In short, it looks like a 10m diameter blunt body design can land more mass than the 10m x 30m shape used in DRA 5. Unexpected!

Even though a DRA 5 style biconic presents an area to the airstream that's >3 times larger than a 10m blunt body, it's apparently much less draggy. Adding fins and flattening the base would definitely help that, but only if the nose was pitched up wrt the airstream... 

http://www.ssdl.gatech.edu/papers/conferencePapers/AIAA-2009-6684.pdf
« Last Edit: 11/28/2013 05:03 pm by adrianwyard »

Offline adrianwyard

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Re: Manned Mars Lander
« Reply #32 on: 11/28/2013 05:28 am »
Continuing on from my previous post on deployable rigid heat shields/aerosurfaces:

Most depictions of Mars landers show comparatively large heat shield diameters - as expected for the thin atmosphere. But only a few have shown deployable structures. I wonder why. Perhaps the complexity of the deploy mechanism adds more mass than you gain back?

Some versions of Zubrin's Mars Direct lander have used an umbrella-like 23m fabric shield, or unfolding, overlapping petals as shown at 0:58 in the following video. It appears to deploy to around 14m.


For fun, I’ve mocked up what a 5m heat shield would look like on a SpaceX Dragon (Red Dragon with Super Dracos). It would need a fairing with the same geometry as that used on the 5m Falcon 9. See Fig 1: "5m-fairing", below.

But rather than just ejecting that upper fairing, it could be kept as heat shield extension panels. See Fig 2: “extensions”. The blue panels are raised slightly to preserve the slight pitch angle (and therefore lift and steering) along the same axis as the regular Dragon.

The total heat shield area is now approx. three times that of the stock 3.7m Dragon (34.6 sq.m vs 11 sq.m). The difference can be seen in Fig 3. The view from below is depicted in Fig 4.

The resulting star shapes are unusual, but the edges are curved away from the airstream, and need not be sharp, so I’m guessing they could withstand the heating…

It is hoped that a Falcon Heavy will throw ~10 mt to Mars, which would allow a Red Dragon to bring ~1 t to the surface. The question is: will carrying the extra weight of a 5m extensible heat shield ultimately allow more than 1 t to be delivered to the surface? Note that in this “Red Dragon 2” version the heat shield is released when retropropulsion starts (~10sec before touchdown), so the actual vehicle mass to be decelerated is less than with the standard Red Dragon concept. Also, the payload can be slung underneath rather than inside the Dragon - good for rovers.

If it turns out that increasing the area provides a net gain, then a larger fairing/panels can be used. Fig 5: big-fairing.

Comments and corrections welcome...

Note: the idea of using a detachable larger heat shield was first discussed in the Red Dragon thread last year:
http://forum.nasaspaceflight.com/index.php?topic=26269.msg931942#msg931942
« Last Edit: 11/28/2013 04:22 pm by adrianwyard »

Offline cordwainer

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Re: Manned Mars Lander
« Reply #33 on: 11/29/2013 01:08 am »
Use a tethered powered landing like MSL did with a staged disposable lander would probably be the cheapest way to do it. Tethered rockets to slow descent and a two staged lander. First stage provides precise powered landing capability and is left behind while the 2nd stage is used for ascent. Also gives the science geeks lots of different systems they have to design so it keeps the NASA boys gainfully employed. Do it the good old fashioned overly complicated American Way!

Offline adrianwyard

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Re: Manned Mars Lander
« Reply #34 on: 11/29/2013 07:29 pm »
More numbers on the Dragon mockup: A 5m heat shield with the upper fairing retained as extensions gives the equivalent area of a 6.6m diameter circular shield. The area opened up between the Dragon and the heat shield is 1.2m high, so tall enough to fit something Curiosity-sized but not with any ground clearance.

Offline Hanelyp

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Offline adrianwyard

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Re: Manned Mars Lander
« Reply #36 on: 11/30/2013 06:03 pm »
Absolutely, hypercones et al do look very promising. Here's a variant that extends a rigid aeroshell, and might be more appropriate for a minimal enhancement to Red Dragon:

http://www.nasa.gov/mission_pages/tdm/ldsd/index.html#.UpoxjZE6G2k

You could use it to extend SpaceX's current 3.7m shield, or to replace the fairing/shield panels that extend beyond the 5m one depicted above. Although, since the extensions in my mockup are also the fairing, they come for almost no mass penalty.

I wonder if inflatable technology could be applied to the huge (10m x 30m) biconic in DRA 5.

I think there are two classes of problem here: 1] how to get more than 1 mt to Mars (current limit) at all, even if it's just 3-5 mt. 2] how to land really huge, really heavy things that would be needed for a human mission - the sort of lander depicted in the video at the beginning of this thread.


Offline RonM

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Re: Manned Mars Lander
« Reply #37 on: 11/30/2013 06:29 pm »
Because of the amount of debris kicked up during landings, NASA did some research into preparing landing pads.

http://www.sciencedaily.com/releases/2012/09/120920101035.htm

Basically, to prevent damage during the landing of a large craft, robotic rovers would be sent in advance to prep a landing pad.

Offline A_M_Swallow

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Re: Manned Mars Lander
« Reply #38 on: 12/01/2013 03:53 am »
{snip}
Basically, to prevent damage during the landing of a large craft, robotic rovers would be sent in advance to prep a landing pad.


If the same rover can prepare the land for the habitat and ISRU equipment then the robotic rover may be worthwhile.

Offline Lobo

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Re: Manned Mars Lander
« Reply #39 on: 12/03/2013 04:49 pm »
Use a tethered powered landing like MSL did with a staged disposable lander would probably be the cheapest way to do it. Tethered rockets to slow descent and a two staged lander. First stage provides precise powered landing capability and is left behind while the 2nd stage is used for ascent. Also gives the science geeks lots of different systems they have to design so it keeps the NASA boys gainfully employed. Do it the good old fashioned overly complicated American Way!

There's a concept I saw on an old Direct paper about Jupiter going to Mars.  They had a concept of a biconic aeroshell that opened up into a rigid parachute like decelerator which had retro rockets like the MSL.  The lander itself then lowered down on a tether, and the was softly dropped on the ground, then the aeroshell/rigid parachute flew off for safe ground impact.

The aeroshell basiclly had four petals on the front that opened up at supersonic terminal velocity to help slow the lander down more.  Obviously it would need a certain amount of dV from retro propulsion.  More than if some big soft parachutes were used, but less than if landing a biconic or blunt body shape propusively.

It was a very interesting concept.  However, I'm still of a bit of a mind that just a big blunt body with sufficient retro propulsion is probably the way to go for large payloads.   Like a big scaled up Dragon capsule with the minimum sidewall angle possible for maximum internal volume.  And you compensate for the less mass efficient design by building bigger dumb, cheap rockets to throw the extra mass, and the simplicity of landing something like a big Dragon capsule, and not messing around with giant supersonic parachutes that must be deployed quickly, or biconic designs which could have issues of control coming into the Martian atmosphere (at least I don't think such a design has ever been used for EDL in that way, so there's be a certain development curve.)
Blunt bodies are well understood and tested and can land without needing to jettison the entire biconic.  They can just jettion the heat shield, or not jettison it and just land it like RedDragon.

Now, for a cargo lander, an interesting concept would be to just have a big Dragon like capsule (say 12m diameter at the bottom or so) and then once on the ground, have it open up with petals similar to what Adrianwyard showed above for a large Dragon heat shield.  Except, have that arrangement with the capsule's sidewalls, leaving the payload full open and just sitting on a short platform.  that might be difficult with the rockets in the sidewalls.  If so, then just have one big door in the side that opens into a ramb that the cargo can be offloaded.  For a cargo lander, you don't need the actual pressure vessel inside like the Dragon pressure vessel.  You can just have the unpressurized "shell" with cargo hanger inside.
A hab lander could be the same thing, just with a pressurized hab module inside that shell.   

Have a single large rocket (like MCT) that can launch this Super RedDragon type capsule directly to MArs and through direct EDL.  Common platform, but you can put whatever you want inside.  Land more cargo and hab configurations as necessary.
The only different element needed is a Mars Ascent vehicle. If you were to use inflatable Bigelow modules in cycler oribts, then you MAV can basically just be a standard size Dragon capsule with a propulsion module under it that would launch the crew to a rendezvous trajectory with the cycler for the trip home, and the crew would do Earth EDL in that Dragon capsule once the propulsion module is jettisoned. 
Do the same thing for the trip to Mars.  Launch the crew in a (Red) Dragon Capsule into a rendezvous trajectory with the outbound cycler, and the crew lands in that. 
That can all be done with a man-rated FH, so that the bigger MCT/FX never needs to be man-rated.  It's just a big, dumb, [probably partially reusable] cargo launcher. 
« Last Edit: 12/03/2013 04:50 pm by Lobo »

Offline high road

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Re: Manned Mars Lander
« Reply #40 on: 12/04/2013 10:45 am »
Because of the amount of debris kicked up during landings, NASA did some research into preparing landing pads.

http://www.sciencedaily.com/releases/2012/09/120920101035.htm

Basically, to prevent damage during the landing of a large craft, robotic rovers would be sent in advance to prep a landing pad.

Isn't a landing area several km across? Is the entire area going to be stabilized/excavated? If the spacecraft is already moving slow enough to land with precision of a few meters, isn't it already moving slow enough to just land?

Offline eriblo

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Re: Manned Mars Lander
« Reply #41 on: 12/04/2013 12:18 pm »
Because of the amount of debris kicked up during landings, NASA did some research into preparing landing pads.

http://www.sciencedaily.com/releases/2012/09/120920101035.htm

Basically, to prevent damage during the landing of a large craft, robotic rovers would be sent in advance to prep a landing pad.

Isn't a landing area several km across? Is the entire area going to be stabilized/excavated? If the spacecraft is already moving slow enough to land with precision of a few meters, isn't it already moving slow enough to just land?

Landing anything big (Curiosity size and up) on Mars already requires using rocket engines and the idea is usually to simply use them all the way down to a soft landing at a specific point. The problem is that you will be pointing one or more fairly large rocket engines more or less straight into the ground. If its just sand/gravel/rocks you are effectively operating mankinds most powerful sand blaster. The high velocity debris can severely damage your lander as well as anything close by (like a previously landed habitat or power plant) - rocks can fly for a surprisingly long distance in the thin atmosphere. You might even be digging a hole big enough to topple the lander or at least make it really hard to get out :(

The pads mentioned in the article are leveled and reinforced to prevent this, on the order of 50-100 m in diameter and with the central part being covered with something more resistant to the engine exhaust.

Offline JasonAW3

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Re: Manned Mars Lander
« Reply #42 on: 12/04/2013 08:13 pm »
Crazy idea.

      A warmed CO2 filled balloon parachute.  You could use a more substantile fabric than even the latest parachute used for the Mars Laboratory.  And even though it would still be in a VERY thin atmosphere, it should provide at least some amount of drag.

     The current inflatable reentry system could be used as a basic model combines with some of the design of a supersonic parachute.

     Or, if you want to get COMPLETELY crazy, a semi inflated heat shield the size of a fooball stadium.  You would inflate the outer rim and eight spokes going out to the rim itself.  Steering could be accomplished by reducing pressure in one or more spokes so the total mass will push in the partially deflated section's direction.

     At a certain altitude, you'd cut loose the heat shield and pop a parachute, and use rocket thrust for the last bit of descent.

Like I said, Crazy idea.

Jason
« Last Edit: 12/04/2013 08:15 pm by JasonAW3 »
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Offline QuantumG

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Re: Manned Mars Lander
« Reply #43 on: 12/04/2013 09:21 pm »
Landing anything big (Curiosity size and up) on Mars already requires using rocket engines and the idea is usually to simply use them all the way down to a soft landing at a specific point.

What if you're landing "anything big" that doesn't require soft landing?

Random example: food.

Human spaceflight is basically just LARPing now.

Offline JohnFornaro

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Re: Manned Mars Lander
« Reply #44 on: 12/04/2013 10:46 pm »
Hyperion:

Thanks for posting that NASA video.  It make one want to believe that landing people on Mars is possible.  Note that the MAV is vertical capsule mounted in the middle of one of the horizontal landers.

The two unmanned landings have to be pretty close together.  Considering the blast zone and flying debris talked about above, one wonders how close these two unmanned landings could really be.
Sometimes I just flat out don't get it.

Offline gbaikie

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Re: Manned Mars Lander
« Reply #45 on: 12/04/2013 11:08 pm »
Landing anything big (Curiosity size and up) on Mars already requires using rocket engines and the idea is usually to simply use them all the way down to a soft landing at a specific point.

What if you're landing "anything big" that doesn't require soft landing?

Random example: food.

Speed of sound into a 10 feet of snow?
Or speed of sound with some sort of impactor design to keep gees to about constant 100.
So tube/pipe which pile drives into surface? absorbing shock both with penetrating ground
and payload sliding down tube with ever steeper resistance. So tube being about 5' long.
And/or 5 feet of crumple zone- made of stuff which could have value as scrap- metal, plastics, etc.

Offline QuantumG

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Re: Manned Mars Lander
« Reply #46 on: 12/04/2013 11:22 pm »
Landing anything big (Curiosity size and up) on Mars already requires using rocket engines and the idea is usually to simply use them all the way down to a soft landing at a specific point.

What if you're landing "anything big" that doesn't require soft landing?

Random example: food.

Speed of sound into a 10 feet of snow?
Or speed of sound with some sort of impactor design to keep gees to about constant 100.
So tube/pipe which pile drives into surface? absorbing shock both with penetrating ground
and payload sliding down tube with ever steeper resistance. So tube being about 5' long.
And/or 5 feet of crumple zone- made of stuff which could have value as scrap- metal, plastics, etc.

Parachute + airbags should be sufficient for food deliveries to Mars.

I remember Jim posted some numbers when people were wondering why NASA didn't send more Spirit/Opportunity missions.
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Offline eriblo

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Re: Manned Mars Lander
« Reply #47 on: 12/05/2013 02:13 pm »
Landing anything big (Curiosity size and up) on Mars already requires using rocket engines and the idea is usually to simply use them all the way down to a soft landing at a specific point.

What if you're landing "anything big" that doesn't require soft landing?

Random example: food.

Speed of sound into a 10 feet of snow?
Or speed of sound with some sort of impactor design to keep gees to about constant 100.
So tube/pipe which pile drives into surface? absorbing shock both with penetrating ground
and payload sliding down tube with ever steeper resistance. So tube being about 5' long.
And/or 5 feet of crumple zone- made of stuff which could have value as scrap- metal, plastics, etc.

Parachute + airbags should be sufficient for food deliveries to Mars.

I remember Jim posted some numbers when people were wondering why NASA didn't send more Spirit/Opportunity missions.

Well, we were talking about soft landing (of large landers) but that's of course not always a requirement. Curiosity sized payloads are possible (IIRC) with just parachutes and airbags if you don't mind the payload sitting in a big pile of fabric after landing, and they will probably work for larger but less sensitive loads as well. Heck, if all you're sending down is solid metal or thermoplastic for local production you could possibly skip those too ;).
But it would require enough things being sent down to make it practical to separate out the "hard-landable" items as well as a significant roving capability on the ground...

Offline JasonAW3

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Re: Manned Mars Lander
« Reply #48 on: 12/05/2013 06:36 pm »
Liken the lander to a Skycrane helicopter, minus rotating parts.  The helo can operate by itself or it can carry cargo containers, vehicles or equipment underslung.

The lander would be the same.  It would contain the crewed area, all propulsion, tankage, avionics and life support.  It could be used solely as a crew transport or as a cargo lander.  I cannot remember who suggested this idea on another thread but if ISRU is available then the lander can fill up on the surface and launch with all the ascent and descent prop required for the next cycle.

Cargo can be hab, power station, ISRU plant, rovers, MPLM type containers, anything that could be made in, or fitted into the same shape and mass limits.

Mick.

That was me.

     The idea being that it could either be used as a substitute for a Crasher stage or a semi reusable system.  By piloting from the Hab module, you eliminate a great deal of weight and can automate a landing nearby, (but far enough away to avoid debris blasting the habitat) on fairly unsophistacated landing gear.

Jason.
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Offline savuporo

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Re: Manned Mars Lander
« Reply #49 on: 12/05/2013 06:45 pm »
Parachute + airbags should be sufficient for food deliveries to Mars.

s/food deliveries/bulk goods and materials/

This leaves the problem of getting the goods to the base from the landing ellipse. I wonder if there have been any serious studies of moving payloads like these with self-reconfiguring modular robots.
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Offline JasonAW3

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Re: Manned Mars Lander
« Reply #50 on: 12/05/2013 07:11 pm »
Ok,

     Another crazy idea.

     What about a reentry powered supersonic propulsive deceleration system?  In short, a series of tubes are woven in the TPS (Inward of the heating surface), and a fluid, (Water) is run through these tubes to help cool the TPS and minimize alblation.  The superheated water (Now superheated steam) would be released from strategically placed exhaust nozzels along the sides of the aeroshell.  This would act to both cool teh TPS shield and provide an additional degree of deceleration to the craft before deploying its' parachute and making the final propulsive landing.

     The steam jets could be throttled for steering as needed during the initial descent for better targeting of teh landing site.

     I'm not quite sure how much additiona mass this would add to the overall scheme, but the accuracy and reduction of mass for the TPS shell should help counterbalance the added mass.

Just a thought...

Jason
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Offline Hanelyp

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Re: Manned Mars Lander
« Reply #51 on: 12/06/2013 01:28 am »
A similar actively cooled heat shield was proposed for http://www.astronautix.com/lvs/rombus.htm

Offline TaylorR137

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Re: Manned Mars Lander
« Reply #52 on: 12/16/2013 11:41 pm »
Here's my concept "Space Shuttle 2.0" - 10m x 30m - same basic EDL as DRM5, ~100 tons at Mars Entry.

The idea is to get a Mars mission (or moon, or asteroid) out of a single SLS launch with in orbit rendezvous of commercially delivered fuel in drop tanks, which makes for a good low cost payload for RLVs, optimized and program survivability rather than IMLEO. The concept artist (Stanley Von Medvey) sketched it launching on FX Heavy though as he's a SpaceX fan. Also shown is an inflatable habitat that could be left in Mars orbit before EDL.

At the core of the vehicle is an elevator that allows for shifting the center of gravity during descent, and the legs double as control surfaces similar to hypersonic test vehicles.

« Last Edit: 12/20/2013 05:08 am by TaylorR137 »

Offline Lars_J

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Re: Manned Mars Lander
« Reply #53 on: 12/17/2013 03:26 am »
I like it - a very cool concept. (Similar to what I have presented earlier) But the location of the cockpit makes little sense... This won't fly like a shuttle.
« Last Edit: 12/17/2013 03:28 am by Lars_J »

Offline TaylorR137

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Manned Mars Lander
« Reply #54 on: 12/17/2013 03:51 am »
I concede that but it reminds people of the shuttle so we decide to leave it as is. After all, Mars landings will certainly be automated given the need for a 3-6G burn just before touchdown with tight margins. I'm also leaning towards an engines-first descent with the nozzles flush with the heat shield, given the loads the rollover maneuver before would put on structures, and the need to keep the docking port safe.

Actually Stanley has just such a concept (which predates mine), "Hydra"

Edit: Image uploaded - I was on a mobile device which didn't allow attaching.
« Last Edit: 12/17/2013 04:07 am by TaylorR137 »

Offline Lars_J

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Re: Manned Mars Lander
« Reply #55 on: 12/17/2013 04:04 am »
Don't embed these huge images, it breaks the site layout. Attach the images.

Offline cordwainer

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Re: Manned Mars Lander
« Reply #56 on: 12/17/2013 04:09 am »
Well, here is my crazy idea. Imagine a giant umbrella made up of Kevlar airbags with the pointy end dropping towards Mars. The umbrella is spread out just wide enough to act as an air deflector for a rocket engine tethered to the "handle" of the umbrella. The "air deflector" reduces the need for a heat shield for both the landing module and the tethered deceleration rocket. When you get relatively close to the surface at a few hundred meters you jettison the rocket engine and deploy drag chutes. The "umbrella" unfolds within 25 to 30 meters of the surface and acts like a shock absorber. Now you have a ready made ramp to roll out vehicles and supplies along. Your now "flattened" umbrella is designed with large hollow cavities between the support "spokes" to channel the exhaust from the rocket thrusters for the return-to-orbit crew module.

Offline cordwainer

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Re: Manned Mars Lander
« Reply #57 on: 12/17/2013 04:32 am »
Now here is my "really crazy idea". Build jumbo size NTR's that can carry thousands of tons to LEO and use them the colonize the inner solar system in one shot. Design them with tall landing gear struts and aero-spike nozzles so they can take off safely from a planetary surface without a gantry and exhaust trench. Put NEP engines at the nose of the rocket for reaction control and put your cargo/crew modules on mobile tracked platforms in a  "piggybacked" configuration attached to the sides of the fuselage. The platforms act like elevators lowering the cargo modules after landing and raising them safely out of the way during launch. Launch a few of these beasts to act as space station/ refueling points for moon shuttles. Send the rest to the Moon to lay down a sizable settlement with nuclear reactors to provide your initial power source. Your space stations rockets would carry moon shuttles as well as vehicles for the initial "claim staking" manned mission to Mars. These Mars Express Transports would be based on compact powerful propulsion designs like Mini-Mag Orion or Magnetic Liner Fusion propulsion so you could beat any competing nations to the punch by quickly laying down a settlement on Mars. Once your moon settlements had enough ISRU capability set up they would refuel some of their NTR's load them up and send a larger settlement population to Mars. Over time Mass drivers would be built on the Moon to supply Earth and Mars with rare materials and micro-gravity manufactured goods. Yeah, highly unlikely any nation would spend the money on something that crazy. Although those giant lines in the Ghobi desert look awfully suspicious.

Offline go4mars

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Re: Manned Mars Lander
« Reply #58 on: 12/17/2013 04:54 am »
Aim your orbital mirrors at relatively unstable solid carbon dioxide in the area you intend to land; immediately before your land there.  Transient localized increase in atmospheric pressure will increase drag and downmass. 

Feel free to take that one @boredelonmusk!
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Offline Lars_J

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Re: Manned Mars Lander
« Reply #59 on: 12/17/2013 06:57 am »
I concede that but it reminds people of the shuttle so we decide to leave it as is. After all, Mars landings will certainly be automated given the need for a 3-6G burn just before touchdown with tight margins. I'm also leaning towards an engines-first descent with the nozzles flush with the heat shield, given the loads the rollover maneuver before would put on structures, and the need to keep the docking port safe.

Actually Stanley has just such a concept (which predates mine), "Hydra"

Edit: Image uploaded - I was on a mobile device which didn't allow attaching.

TaylorR137 - Do you have a cross-section of your concept? I'm curious about where the crew areas are, and the size of the propellant tanks.

I have to say that the landed view is my favourite - a very cool concept for unloading cargo.

Offline TaylorR137

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Re: Manned Mars Lander
« Reply #60 on: 12/17/2013 07:07 am »
Cross sections will be forthcoming, the project is actually more software than a specific vehicle design. You specify the vehicle exterior shape, calculate Newtonian aerodynamics, EDL trajectories, etc. It's meant to be easy for anyone to use. (E.g. A five year old mashing buttons will still result in a functioning spacecraft) You get to choose engine and landing gear configurations, place tanks and habitable volumes, reactors or solar panels, structures, heat shields, etc. All of which effect the center of gravity and trajectories. The core game mechanic is design and analysis rather than real time flying, with crowd sourced subsystems.

Offline RanulfC

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Re: Manned Mars Lander
« Reply #61 on: 12/17/2013 01:08 pm »
Cross sections will be forthcoming, the project is actually more software than a specific vehicle design. You specify the vehicle exterior shape, calculate Newtonian aerodynamics, EDL trajectories, etc. It's meant to be easy for anyone to use. (E.g. A five year old mashing buttons will still result in a functioning spacecraft) You get to choose engine and landing gear configurations, place tanks and habitable volumes, reactors or solar panels, structures, heat shields, etc. All of which effect the center of gravity and trajectories. The core game mechanic is design and analysis rather than real time flying, with crowd sourced subsystems.

But the vehicle designs are so COOL! :)

I see the "Shuttle" as a Dragon-III design capable of going to the Moon and back. (I also noted that the LV is very "Falcon-9 Heavy" like as well and the "SpaceX" on the Hydra :))

Randy
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Offline RanulfC

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Re: Manned Mars Lander
« Reply #62 on: 12/17/2013 01:17 pm »
And does the artist do commission work? :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Rocket Science

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Re: Manned Mars Lander
« Reply #63 on: 12/17/2013 02:01 pm »
Here's my concept "Space Shuttle 2.0" - 10m x 30m - same basic EDL as DRM5, ~100 tons at Mars Entry.

The idea is to get a Mars mission (or moon, or asteroid) out of a single SLS launch with in orbit rendezvous of commercially delivered fuel in drop tanks, which makes for a good low cost payload for RLVs, optimized and program survivability rather than IMLEO. The concept artist (Stanley Von Medvey) sketched it launching on FX Heavy though as he's a SpaceX fan. Also shown is an inflatable habitat that could be left in Mars orbit before EDL.

At the core of the vehicle is an elevator that doubles as a drilling rig for water for methane ISRU.

The legs double as control surfaces similar to hypersonic test vehicles.
Nice artwork there! :) The hatch on the nose is a little iffy being a high heat area, I'd rather see the Hab on top near the Flight deck. Keep up the good work!  ;)
« Last Edit: 12/17/2013 02:02 pm by Rocket Science »
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Offline JasonAW3

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Re: Manned Mars Lander
« Reply #64 on: 12/17/2013 08:22 pm »
Cross sections will be forthcoming, the project is actually more software than a specific vehicle design. You specify the vehicle exterior shape, calculate Newtonian aerodynamics, EDL trajectories, etc. It's meant to be easy for anyone to use. (E.g. A five year old mashing buttons will still result in a functioning spacecraft) You get to choose engine and landing gear configurations, place tanks and habitable volumes, reactors or solar panels, structures, heat shields, etc. All of which effect the center of gravity and trajectories. The core game mechanic is design and analysis rather than real time flying, with crowd sourced subsystems.

So,

      Where can I get a copy of this software?

Jason
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Offline TaylorR137

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Re: Manned Mars Lander
« Reply #65 on: 12/17/2013 09:21 pm »


And does the artist do commission work? :)

Randy

He does indeed. http://www.stanleyvonmedvey.com


Cross sections will be forthcoming, the project is actually more software than a specific vehicle design. You specify the vehicle exterior shape, calculate Newtonian aerodynamics, EDL trajectories, etc. It's meant to be easy for anyone to use. (E.g. A five year old mashing buttons will still result in a functioning spacecraft) You get to choose engine and landing gear configurations, place tanks and habitable volumes, reactors or solar panels, structures, heat shields, etc. All of which effect the center of gravity and trajectories. The core game mechanic is design and analysis rather than real time flying, with crowd sourced subsystems.

So,

      Where can I get a copy of this software?

Jason


It's not out yet, I'm working on getting the demo functioning then launching a crowdfunding campaign.

The software will be free. I'm funding the endeavor by selling custom 3d prints of designs. Hopefully a few of those will end up in wind tunnels!

Offline TaylorR137

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Re: Manned Mars Lander
« Reply #66 on: 12/17/2013 09:23 pm »
Here's another piece of concept art, something halfway between Space Shuttle 2.0 and Hydra

Offline Lars_J

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Re: Manned Mars Lander
« Reply #67 on: 12/17/2013 09:58 pm »
Here's another piece of concept art, something halfway between Space Shuttle 2.0 and Hydra

That is very cool... The smaller size of this concept looks similar to stretched a F9/FH payload fairing, with similar "legs" as the concept on the earlier stage.

Offline TaylorR137

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Re: Manned Mars Lander
« Reply #68 on: 12/17/2013 10:13 pm »
Here's another piece of concept art, something halfway between Space Shuttle 2.0 and Hydra

That is very cool... The smaller size of this concept looks similar to stretched a F9/FH payload fairing, with similar "legs" as the concept on the earlier stage.

Indeed. I should note while I commissioned the Space Shuttle 2.0 artwork Stanley did Hydra and this piece on his own, I take no credit. Its also worth mentioning both were done before SpaceX revealed their own landing gear designs or the specifications for Raptor.

Offline JasonAW3

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Re: Manned Mars Lander
« Reply #69 on: 12/17/2013 11:11 pm »


And does the artist do commission work? :)

Randy

He does indeed. http://www.stanleyvonmedvey.com


Cross sections will be forthcoming, the project is actually more software than a specific vehicle design. You specify the vehicle exterior shape, calculate Newtonian aerodynamics, EDL trajectories, etc. It's meant to be easy for anyone to use. (E.g. A five year old mashing buttons will still result in a functioning spacecraft) You get to choose engine and landing gear configurations, place tanks and habitable volumes, reactors or solar panels, structures, heat shields, etc. All of which effect the center of gravity and trajectories. The core game mechanic is design and analysis rather than real time flying, with crowd sourced subsystems.

So,

      Where can I get a copy of this software?

Jason


It's not out yet, I'm working on getting the demo functioning then launching a crowdfunding campaign.

The software will be free. I'm funding the endeavor by selling custom 3d prints of designs. Hopefully a few of those will end up in wind tunnels!

Does it handle wind tunnel testing?

     I've got a few designs I want to test out, including a blended wing in body lifting body hybrid I want to test out.

Jason
My God!  It's full of universes!

Offline TaylorR137

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Re: Manned Mars Lander
« Reply #70 on: 12/17/2013 11:22 pm »
Alright this will be my last post spilling details but I thought I'd show some of the 3D printed prototypes and the visual style of the software before getting back to work. I've got to get the demo wrapped up and the crowd funding campaign launched ASAP as I'm borrowing money just to pay rent!

The first Image shows lift (green) and drag (red) coefficients at all angles of attack, the exterior of a ship in the first stage of design, and the torque about its center of gravity on the right with equilibrium angles of attack as the radial lines. Airflow is from left to right.

The 3D prints are 1:200 and 1:100 scale, with the Space Shuttle orbiter model from the NASA website printed for comparison. The coloring of the model surface is the Newtonian pressure coefficient.

The last 1:100 model is the closest to a cross section I can show for now, though the tanks in the nose are omitted. This model was infused with a thermoplastic resin for strength, given that it must not flex under the ~100lb compressive load of the steel "tethers"  ;) .

www.TaylorRatliff.com

 
« Last Edit: 12/18/2013 02:43 am by TaylorR137 »

Offline TaylorR137

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Re: Manned Mars Lander
« Reply #71 on: 12/17/2013 11:28 pm »
     I've got a few designs I want to test out, including a blended wing in body lifting body hybrid I want to test out.
Does it handle wind tunnel testing?
Jason

The full version will output 3D models with stings or holes at the center of gravity for you to order or print yourself. Once you do the testing you can submit the data and use it in the EDL simulations, overriding the Newtonian method. This is still a work in progress though, and certainly won't be part of the demo.

Offline Hyperion5

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Re: Manned Mars Lander
« Reply #72 on: 01/02/2014 11:36 pm »
Aim your orbital mirrors at relatively unstable solid carbon dioxide in the area you intend to land; immediately before your land there.  Transient localized increase in atmospheric pressure will increase drag and downmass. 

Feel free to take that one @boredelonmusk!

That sure sounds like whoever has that Twitter account.  Btw, have we reached any sort of consensus about what the ideal mass range would be for a manned Mars lander?  It appears to me we've agreed that it needs to be at least 40 tonnes in mass, with 50 tonnes being a more ideal minimum.  Does anyone believe there is a maximum feasible lander mass?  Or at least not see the lander exceeding a certain mass?

Online MickQ

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Re: Manned Mars Lander
« Reply #73 on: 01/09/2014 09:00 am »
Considering the numbers being accredited to MCT and Raptor in the SpaceX threads I don't think there will be a "Limit"  to what can be landed.  I think it is all going to depend on who requires what in their lander, eg Lander only, MDV/MAV, add a hab, add a hab/rover, ISRU plant, etc.  Where do you stop ?

Mick.

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