Author Topic: Mars Lander  (Read 35288 times)

Offline JamesH

  • Full Member
  • ****
  • Posts: 525
  • United Kingdom
  • Liked: 284
  • Likes Given: 7
Re: Mars Lander
« Reply #40 on: 03/31/2015 05:59 pm »
Here it is from ULA.  Now, I'm talking about equipment landers since they are not going to take back off.  Also Mars is only 38% earths gravity.  Equipment for ISRU is going to be sent first, probably in mass.  Being able to access it without the height restrictions is going to be easier.

http://www.ulalaunch.com/uploads/docs/Published_Papers/Exploration/LunarLanderConfigurationsIncorporatingAccessibility20067284.pdf

We are in the SpaceX section. We are talking about a Mars Lander, I assume from SpaceX. Those will positively go back to Earth for reuse, crewed or cargo. Maybe not the first few, because they bring the ISRU equipment that enables return. But every craft that lands later will go back. Except possibly when they do the first landing on different far away locations where they again have no ISRU working initially.

It is confirmed that the whole MCT will land and then take off again? Or is that just reasoned speculation?

AFAIK, there are scant details of the MCT, and what details there are say practically nothing of the architecture.

Offline spacenut

  • Senior Member
  • *****
  • Posts: 5181
  • East Alabama
  • Liked: 2587
  • Likes Given: 2895
Re: Mars Lander
« Reply #41 on: 03/31/2015 06:23 pm »
MTC is for humans.  My topic was a horizontal lander for equipment, non-humans, so as to be easier to access once they get off the MTC and go to work on the colony.  I thought it was obvious that equipment for ISRU equipment would be landed first to make fuel, water, and oxygen for air to breath just to get started and to refuel to get back.  Solar panels will have to be landed and opened.  Granted a lot of the is can be done robotically, however, access and maintenance will have to be done by humans, and the lower the better for safety of suited up humans.  They could even be landed with wheels on the legs to roll around by a tow vehicle to line up for depots, solar arrays, etc. 
« Last Edit: 04/02/2015 03:09 am by spacenut »

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 7438
  • Germany
  • Liked: 2332
  • Likes Given: 2891
Re: Mars Lander
« Reply #42 on: 03/31/2015 09:05 pm »
MTC is for humans.  My topic was a horizontal lander for equipment, non-humans, so as to be easier to access once they get off the MTC and go to work on the colony.  I thought it was obvious that equipment for ISRU equipment would be landed first to make fuel, water, and oxygen for air to breath just to get started and to refuel to get back.  Solar panels will have to be landed and opened.  Granted a lot of the is can be done robotically, however, access and maintenance will have to be done by humans, and the lower the better for safety of suited up humans.

MCT is not exclusively for humans. It is the Mars Colonial Transport. That includes humans and cargo. Elon Musk has stated over and over that full reusability of the whole system is a requirement to reduce cost enough to make a colony possible. He stated recently that he expects 10 cargo flights for each crew flight. Do you really think he wants full reusability only for 10% crew flights and not for 90%  cargo?


Offline guckyfan

  • Senior Member
  • *****
  • Posts: 7438
  • Germany
  • Liked: 2332
  • Likes Given: 2891
Re: Mars Lander
« Reply #43 on: 03/31/2015 09:10 pm »
It is confirmed that the whole MCT will land and then take off again? Or is that just reasoned speculation?

Mostly reasoned speculation.

The proof might not be considered proof beyond reasonable doubt by court standards. But to me the one statement, "just land the whole thing" by Elon Musk and consideration of the possible options are quite conclusive. For final proof we will have to wait until the architecture will be revealed. That will probably be by the end of this year. But it was also announced to be revealed probably by the end of 2014.

Offline spacenut

  • Senior Member
  • *****
  • Posts: 5181
  • East Alabama
  • Liked: 2587
  • Likes Given: 2895
Re: Mars Lander
« Reply #44 on: 03/31/2015 10:11 pm »
A single purpose lander could have the equipment to make methane and lox for use in other reusable landers.  The tanks for the rocket lander could double as storage for the manufactured fuel.  The MTC would have to be very large for reuse.  I was under the impression that the MTC was for travel between earth and Mars in space. 

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 7438
  • Germany
  • Liked: 2332
  • Likes Given: 2891
Re: Mars Lander
« Reply #45 on: 03/31/2015 10:34 pm »
I was under the impression that the MTC was for travel between earth and Mars in space.

It has been discussed many times. There is no unanimous opinion. But I think most see MCT as a vehicle that launches from Earth, is refuelled in LEO, flies to Mars and lands directly, bypassing orbit. Then gets refuelled on the surface of Mars and flies back, does Earth landung for maintenance and fly again next launch window.

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6915
  • Spokane, WA
  • Liked: 672
  • Likes Given: 437
Re: Mars Lander
« Reply #46 on: 03/31/2015 11:23 pm »
Do they really need to land horizontally?

No of course not. It is just one of these ideas that keep popping up because nobody stakes them through the heart once and for all.

Like artificial gravity for Mars transfer. Or hydrogen upper stages for Falcon 9/FH.

There are reasons for horizontal landers.  The major one being it's far easier to get heavy cargo off loaded, and assuming the crew cabin is on top of a vertical lander, it's far easier and safer to get crew into and out of a horizontal lander without risk of a major injury or death due to a fall.
If you want to get that 2000lb rover off the lander and onto the ground, it's easier if it's 5 ft above the ground rather than 30ft above the ground...even in 1/3 gravity.

But there are advantages to vertical landers too.


I think a small swing-out crane and tackle system would be simpler and lighter than the hardware needed for horizontal landing.

And I'm not saying I disagree, just saying there are benefits of the horizontal layout.

Here's one thing of a Mars lander vs. Lunar lander.  Horizontal lunar landers have the additional penalty of needed two different propulsion systems.  One in the aft that will provide most of the dV to slow the lander down prior to landing, and then a ventral one that will land it on the surface.  Which is pretty inefficient.  (think DTAL).

However, on Mars, the atmosphere is providing a lot of dV to slow the lander.  Especially if you are just landing and not having to ascend again, the ventral thrusters on a horizontal lander could provide enough dV that it wouldn't need a separate large aft engine system.  Your lander can be something like the MSL craft, except it just lands instead of lowers MSL to the surface and then crash. 
This actually makes a 1-way horizontal Mars lander less inefficient than a 1-way horizontal Lunar lander. 

If you want to take back off in your lander from the surface, then a horizontal lander becomes more tricky because you'll be taking off with multiple engines at the engine's corners, and the horizontal lander will have a pretty aerodynamically inefficient profile for ascent.   Not a huge issue with Mars's thin atmosphere, but an issue nonetheless.
I think for a lander that's planning to make it's own propellant and launch itself back to Earth, a vertical lander is really the only viable configuration.  Then there's just one propulsions system, and it can be minimal and inline with the CoG of the lander.  Those things are important if the lander must launch and not just land.

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2766
  • Liked: 780
  • Likes Given: 1132
Re: Mars Lander
« Reply #47 on: 04/01/2015 03:04 am »
Do they really need to land horizontally?

No of course not. It is just one of these ideas that keep popping up because nobody stakes them through the heart once and for all.

Like artificial gravity for Mars transfer. Or hydrogen upper stages for Falcon 9/FH.

There are reasons for horizontal landers.  The major one being it's far easier to get heavy cargo off loaded, and assuming the crew cabin is on top of a vertical lander, it's far easier and safer to get crew into and out of a horizontal lander without risk of a major injury or death due to a fall.
If you want to get that 2000lb rover off the lander and onto the ground, it's easier if it's 5 ft above the ground rather than 30ft above the ground...even in 1/3 gravity.

But there are advantages to vertical landers too.


I think a small swing-out crane and tackle system would be simpler and lighter than the hardware needed for horizontal landing.

It what way is a crane and tackle simpler and lighter than a horizontal landing?
Apologies in advance for any lack of civility - it's unintended

Offline llanitedave

  • Senior Member
  • *****
  • Posts: 2286
  • Nevada Desert
  • Liked: 1545
  • Likes Given: 2052
Re: Mars Lander
« Reply #48 on: 04/01/2015 03:13 pm »
Do they really need to land horizontally?

No of course not. It is just one of these ideas that keep popping up because nobody stakes them through the heart once and for all.

Like artificial gravity for Mars transfer. Or hydrogen upper stages for Falcon 9/FH.

There are reasons for horizontal landers.  The major one being it's far easier to get heavy cargo off loaded, and assuming the crew cabin is on top of a vertical lander, it's far easier and safer to get crew into and out of a horizontal lander without risk of a major injury or death due to a fall.
If you want to get that 2000lb rover off the lander and onto the ground, it's easier if it's 5 ft above the ground rather than 30ft above the ground...even in 1/3 gravity.

But there are advantages to vertical landers too.


I think a small swing-out crane and tackle system would be simpler and lighter than the hardware needed for horizontal landing.

It what way is a crane and tackle simpler and lighter than a horizontal landing?


Far less hardware, simpler maneuvering, easier turnaround in case of a planned return.
« Last Edit: 04/01/2015 10:14 pm by llanitedave »
"I've just abducted an alien -- now what?"

Offline spacenut

  • Senior Member
  • *****
  • Posts: 5181
  • East Alabama
  • Liked: 2587
  • Likes Given: 2895
Re: Mars Lander
« Reply #49 on: 04/01/2015 06:41 pm »
SpaceX mentioned they would use the Falcon heavy for Mars.  Excluding the BFR and The MCT what for?  I think they might use a Falcon heavy horizontal lander for solar panels, ISRU equipment, or vehicles for transport, excavation, etc, that will not be brought back.  Therefore it wouldn't have to take back off.  Maybe Nasa might want a sample return.  Some of this equipment will need to be sent before humans to get fuel made for return, and have power when they get there, along with water and air to breathe.  Some of this doesn't have to be 100 tons, but 5 -10 ton pieces of equipment, possibly with a horizontal lander from technology developed for 2nd stage return and reuse after they get the first stage returned regularly.

MCT will probably be 30 meters wide so it will not have to be horizontal.  However, whatever they plan to send using Falcon heavy might be horizontal because of launch diameter restrictions. 

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2766
  • Liked: 780
  • Likes Given: 1132
Re: Mars Lander
« Reply #50 on: 04/01/2015 09:21 pm »
Quote

It what way is a crane and tackle simpler and lighter than a horizontal landing?


Far less hardware, simpler maneuvering, easier turnaround in case of a planned return.[/size]

A horizontal lander has the same amount of hardware as any other kind of lander. 

Maneuvering is not more complex as all spacecraft have to be oriented for propulsion burns in space.  On the surface it is much easier to move a horizontal landiner than a vertical one as the centre of gravity is lower. 

As for easier turnaround, I don't get this at all.  Why would it be easier?
« Last Edit: 04/02/2015 01:59 am by Dalhousie »
Apologies in advance for any lack of civility - it's unintended

Offline BobHk

  • Full Member
  • ***
  • Posts: 324
  • Texas
  • Liked: 91
  • Likes Given: 173
Re: Mars Lander
« Reply #51 on: 04/02/2015 01:40 am »
@llanitedave
I can't see any advantages to a horizontal lander either.
I think of the weight of the rockets on the 1st stage F9R.  Its center of gravity, with fuel expended, is all in the bottom.  A vertical take off and landing rocket has one set of rockets, doesn't require wings (folding x-wing control surfaces aside) or a runway.  Horizontal landers bring nothing to the party (the Mars party especially considering lack of infrastructure) that isn't offset by a vertical landing rockets advantages/efficiencies. 

@spacenut
Ten meter wide theoretical MCT/boosters would be sufficient to boost 100 ish tons to orbit.  The fairing can be a bit wider, but not 30 meters.  That seems a bit outlandish.

@llanitedave
I'm guessing a crane system that could load and unload the entire top half of a vertical mct lander from the rocket body to the martian soil would weigh much less than a second set of engines and pipes needed for a horizontal lander.  And not just because the crane can use the existing vertical rocket body as its own frame and offset mass for lifting.

Offline Dalhousie

  • Senior Member
  • *****
  • Posts: 2766
  • Liked: 780
  • Likes Given: 1132
Re: Mars Lander
« Reply #52 on: 04/02/2015 02:03 am »
@llanitedave
I can't see any advantages to a horizontal lander either.
I think of the weight of the rockets on the 1st stage F9R.  Its center of gravity, with fuel expended, is all in the bottom.  A vertical take off and landing rocket has one set of rockets, doesn't require wings (folding x-wing control surfaces aside) or a runway.  Horizontal landers bring nothing to the party (the Mars party especially considering lack of infrastructure) that isn't offset by a vertical landing rockets advantages/efficiencies. 

Horizontal landers don't need runways.  They land vertically, but with the long axis parallel to the ground, as opposed to right angles to it.

http://www.wired.com/images_blogs/wiredscience/2014/01/0110b.jpg

Think Harrier as opposed to XFY-1
Apologies in advance for any lack of civility - it's unintended

Offline spacenut

  • Senior Member
  • *****
  • Posts: 5181
  • East Alabama
  • Liked: 2587
  • Likes Given: 2895
Re: Mars Lander
« Reply #53 on: 04/02/2015 03:07 am »
Horizontal landers would not have the rocket engines on the bottom, or end.  They are launched, fully fueled, or refuel at a fuel depot along the way.  They either come from a mother ship or are launched independently.  After coming through the atmosphere, they land horizontally.  Tanks can be on either end with engines in the middle sideways.  Mars atmosphere isn't too thick so just some type of heat shield, maybe an inflatable one would be all that would be necessary.  Also, I'm talking about single purpose, one time only use for equipment or even supplies.  Empty tanks close to the ground could also serve as a shelter, a fuel depot station, etc. 

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6915
  • Spokane, WA
  • Liked: 672
  • Likes Given: 437
Re: Mars Lander
« Reply #54 on: 04/02/2015 06:06 pm »
MCT will probably be 30 meters wide so it will not have to be horizontal.  However, whatever they plan to send using Falcon heavy might be horizontal because of launch diameter restrictions.

30 meters wide?

Where do you get that?

It might be a little wider than BFR itself...so maybe like 12-15m, depending.  But 30?

Offline Lobo

  • Senior Member
  • *****
  • Posts: 6915
  • Spokane, WA
  • Liked: 672
  • Likes Given: 437
Re: Mars Lander
« Reply #55 on: 04/02/2015 06:42 pm »
Horizontal landers would not have the rocket engines on the bottom, or end.  They are launched, fully fueled, or refuel at a fuel depot along the way.  They either come from a mother ship or are launched independently.  After coming through the atmosphere, they land horizontally.  Tanks can be on either end with engines in the middle sideways.  Mars atmosphere isn't too thick so just some type of heat shield, maybe an inflatable one would be all that would be necessary.  Also, I'm talking about single purpose, one time only use for equipment or even supplies.  Empty tanks close to the ground could also serve as a shelter, a fuel depot station, etc.

It depends what you are talking about.  A 1-way lander that's just landing cargo on Mars and then not used for anything else?  Then a horizontal lander isn't a bad choice.  Mares Science Lab essentially was a horzontal lander that winched the rover to the surface rather than landed.  But it hovered and could have landed itself had there been a need to do so.  One issue with a large horizontal lander is it's TPS system.  MSL and even NASA DRM 5.0 all had jettisonable aeroshells.  A horzontal lander would need something like that as it needs to have engines and landing gear on it's side it it can't have it's TPS system integrated into it's hull.

However, if you want the lander to get itself back off the surface, then a horizontal lander becomes much more problematic.  It has to be able to lift itself off the surface horzontally then pitch over and engage and main propulsion system on it's aft.  It's not going to go all the way to space horizontally as that would be pretty aerodynamically inefficient is it picks up speed.  Not to mention how would it come back down again if it's already jettisoned it's aeroshell the first time?

However, a vertical lander solves some of these issues.  It doesn't need a seprate aeroshell.  It can have the TPS on it's side  as it doesn't have engines or landing gear on the side, and it's very shape can be the biconic aeroshell.  Also it can have a single engine under it's center of gravity that can act both to land, and to launch itself again. 

With MCT, despite there being a lot of speculation about what would essentially be a really big Dragon v2, Personally I more expect it to look like SpaceX's concept for a reusable 2nd stage.  It would enter the Mars atmosphere on it's side and nose to present the maximum surface area.  The prior to landing, it would pitch over to put it's aft down to fire it's engines to land.  Then it's properly oriented to lift off once refueled.  That way you don't have to have a heat shield on the bottom that your main engines need to be able to retract into and out of.  Like a combination between the two pictures below, although the cargo area my not be on the bottom.  While it's nice to have the cargo down low there, I think structurally you'd not want an empty space like that between your engines and your full tanks.   I think you'd want your engine(s) to be directly under those heavy tanks and support them directly when firing.
And I suspect that MCT and an uncrewed BFR-US will share a lot of components, as the uncrewed BFR-US will reenter the atmosphere on Earth and land back at the launch site, just like MCT will do on Mars (and then back on Earth when it returns).
BFR-US will already be a reusable spacecraft and lander.   It just won't have crew accomodations and won't need to get itself off the surface.  But the two will have enough in common I think they'll be a common platform.  Not unlike a DTAL package on a basic ACES upper stage stage, from the ULA DTAL concept.  But vertical rather than horizontal, and fully reusable. 

Offline JasonAW3

  • Senior Member
  • *****
  • Posts: 2443
  • Claremore, Ok.
  • Liked: 410
  • Likes Given: 14
Re: Mars Lander
« Reply #56 on: 04/02/2015 07:26 pm »
Another weird idea;

     Instead of a parachute/propulsive descent after reentry, how about using a ballute that, as the craft descends is filled with heated helium, (Or another light, inert gas.  Just has to be lighter than CO2) and use a balloon descent?  It would require a gass envelope that could handle supersonic speeds while only partially inflated, but if we can build one for the MRL, I'm pretty sure we should be able to do one for a manned lander.  Just got to make it gas impermiable.
My God!  It's full of universes!

Offline GregA

  • Full Member
  • ****
  • Posts: 524
  • Liked: 269
  • Likes Given: 61
Re: Mars Lander
« Reply #57 on: 04/02/2015 10:52 pm »
Vertical landing of the booster is one thing as all the weight is on the bottom.  A Mars only lander could be another shape.  An extremely tall lander on Mars, would be very hard to unload.

An extremely tall lander where the transported material and people are in the BOTTOM, and fuel at the top, would mean that on landing (with little fuel) most of the weight would be at the bottom (like landing the Falcon 1st stage now). It'd also be much easier to unload.

Basically as lobo posted above in the concept photo - although you could have a much longer rocket too.

A fuel tank that enveloped the whole rocket would also be full during transit and offer some protection to the cargo in the centre. But I may be missing something quite obvious....

Offline spacenut

  • Senior Member
  • *****
  • Posts: 5181
  • East Alabama
  • Liked: 2587
  • Likes Given: 2895
Re: Mars Lander
« Reply #58 on: 04/02/2015 11:42 pm »
If all the transported weight is on the bottom and unloaded.  Wouldn't the rocket be top heavy when taking off after refueling on Mars for transport back to earth? 

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 6809
  • California
  • Liked: 8485
  • Likes Given: 5384
Re: Mars Lander
« Reply #59 on: 04/03/2015 12:55 am »
If all the transported weight is on the bottom and unloaded.  Wouldn't the rocket be top heavy when taking off after refueling on Mars for transport back to earth?

A top heavy rocket is not a problem, in fact it is a good thing, since it makes it easier to control. Just like it is easier to balance a long stick on your finger than a short stick.

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
0