Author Topic: Sci-Fi World Building: Design a martian spaceplane  (Read 13969 times)

Offline HlynkaCG

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For the last year or so I've been working on a Near future space opera (Think 2001 or Niven's "Belter" stories) RPG setting and several short stories set in the same. I need a way for my martian colonists to get to orbit and back as well as visit isolated stations on the planet's surface. The image in my head is essentially a large rocket powered "Jump-Jet" optimized for the Martian atmosphere and environment.

My problem is that I have only the vaguest idea of how such an air/spacecraft would look or function. As such I am looking to the internet for inputs and inspiration.

The basic flight profile I'm envisioning is a rolling take-off using vectored thrust, followed by a climb-out using a combination of aerodynamic lift and the main engines. To land it would follow a more or less ballistic trajectory to it's target using aerodynamic lift/drag to steer and bleed off most of it's velocity before transitioning to vectored thrust for landing.



Note how the main engine rotates downward to provide additional lifting force.

Constraints imposed by the needs of plot and universe consistency are...

1: Manned Mars SSTO.
2: Minimum lift capacity of 1.5 metric tonnes to orbit, 5 - 10 tonnes ideal.
3:Total Dv budget of 5 - 6 km/s. *see note
4: Fully reusable, be able to lift off and land multiple times without needing any logistical support other than fuel.
5: Engines use ISRU propellants, currently leaning towards LCH4+LOX.
6: Plausible near-future tech level, no unobtainium required.

*Dv figure arrived at through several test flights made in Orbiter 2010 using the XR-2 and Delta Glider. I would launch from Olympus, attain a 400 km circular orbit, and then return to Olympus noting my fuel consumption along the way. Atmospheric lift was utilized moderately during ascent and for the majority of my descent. Hover-thrusters were only used for lift-off and touchdown.

ETA:
As a starting point I plugged an all-up weight of 80 tonnes (a craft comparable in size and mass to a modern C-130) into Tsiolkovsky's rocket equation. With a mass ratio of 4 and an exhaust velocity of 3650 m/s, the spacecraft would have a total Dv of 5 km/s with a 5 tonne payload. More work needs to be done but I think this represents a good baseline to start from.

Any inputs, suggestions, or constructive criticism/feedback will be greatly appreciated.

Thank you.
« Last Edit: 08/30/2013 04:40 pm by HlynkaCG »

Offline Nilof

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #1 on: 08/30/2013 09:03 pm »
As far as looks go, you could take Skylon as an initial inspiration if you want a spaceplane that takes off horizontally and uses areodynamic lift extensively during ascent. Skylon's shape is optimized for exactly that flight regime. It also avoids being unstable due to engine weight, though a methane based pure rocket engine will probably have a much better T/W than a SABRE so engine weight might not be as much of an issue as it was on HOTOL.

However, there are other operational constraints that might be important. Skylon's shape should give loads of volume, especially if you change to methane and shrink the tanks. On the other hand you don't get a whole lot of width, especially if you scale it down. Another constraint is runway length, unless you're going for a VTOL design.
« Last Edit: 08/30/2013 09:04 pm by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline Andrew_W

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #2 on: 08/31/2013 02:24 am »
A significant contribution from aerodynamic lift for such a craft during ascent to orbit I think unrealistic, just too much weight for any practical wing area in such a thin atmosphere.

So how about HTO with a ski-ramp for orbital flights with that honking big ascent engine and with VL returning from orbit, While on lightly laden surface flights use VTOVL on smaller dual use OMS/VL sized engines?
« Last Edit: 08/31/2013 02:30 am by Andrew_W »
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Offline Lars_J

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #3 on: 08/31/2013 05:10 am »
Why would you insist on aircraft-like operations in an environment so unsuited for it?

People argue about HTOL vs VTOL SSTO's on Earth, but on Mars the debate gets a LOT more one sided.

And if you want the aircraft to be basically a vertical take-off aircraft anyway, may I suggest that you just go ahead and make it a DC-X like vehicle to start with? In the thin atmosphere, wings are far less efficient.

If you want something with fins, the craft could have small ones for improved high speed atmospheric flight control, as the McD X-33 proposal: (and older projects that inspired the DC-X)
« Last Edit: 08/31/2013 05:30 am by Lars_J »

Offline Andrew_W

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #4 on: 08/31/2013 05:24 am »
Why would you insist on aircraft-like operations in an environment so unsuited for it?

People argue about HTOL vs VTOL SSTO's on Earth, but on Mars the debate gets a LOT more one sided.

And if you want the aircraft to be basically a vertical take-off aircraft anyway, may I suggest that you just go ahead and make it a DC-X like vehicle to start with? In the thin atmosphere, wings are far less efficient.

If the wing were light enough it could be justified through saving propellant during reentry and in atmospheric cruising, the big minus would be the shear area required for it to be useful
I confess that in 1901 I said to my brother Orville that man would not fly for fifty years.
Wilbur Wright

Offline HlynkaCG

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #5 on: 08/31/2013 10:04 am »
Quote
Why would you insist on aircraft-like operations in an environment so unsuited for it?

Several reasons. A horizontal vehicle arrangement is more stable as well as being easier to load and unload. Because NASA has a proposed the used of martian gliders and other airborne probes I surmised that a Lifting-body or blended-wing design might provide a meaningful amount of lift while providing an excess amount of volume that I could fill with propellant. Likewise, spaceplanes are cool.

Offline gbaikie

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #6 on: 08/31/2013 10:40 am »
Quote
Why would you insist on aircraft-like operations in an environment so unsuited for it?

Several reasons. A horizontal vehicle arrangement is more stable as well as being easier to load and unload. Because NASA has a proposed the used of martian gliders and other airborne probes I surmised that a Lifting-body or blended-wing design might provide a meaningful amount of lift while providing an excess amount of volume that I could fill with propellant. Likewise, spaceplanes are cool.

It could be glider with some rocket power.
So something like a U-2:
http://en.wikipedia.org/wiki/Lockheed_U-2.

Or a flying wing:
http://en.wikipedia.org/wiki/Flying_wing
Oh, here something- I was wondering about flying wings and supersonic speeds. And ran across this:
http://www.technewsdaily.com/6153-supersonic-flying-wing-nasa.html
"An aircraft that resembles a four-point ninja star could go into supersonic mode by simply turning 90 degrees in midair. The unusual "flying wing" concept has won $100,000 in NASA funding to trying becoming a reality for future passenger jet travel"

On earth Flying wings don't go very fast, but the have great lift and carrying capacity. Of course, one choose to call delta wing designs or lifting bodies as sort of a flying wing- so Shuttle, SR- 71 [very fast vehicles] but I mean like B-2 or the Northrop YB-49 flying wing.

Anyhow that ninja star might make good sfi.

Offline A_M_Swallow

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #7 on: 08/31/2013 02:12 pm »
These are designed to be used on the Moon but being developed on the Earth.

 Xombie GENIE 500m Parabolic EDL Flight


A NASA one.
 Project Morpheus Tether Test 29


If you people want to photograph a valley, a tiny vehicle.
NASA Mighty Eagle, August 28, 2012

The white stuff give off is steam.  The fuel used is hydrogen peroxide, (as used in blond hair dye).

p.s. Update URL
« Last Edit: 08/31/2013 02:13 pm by A_M_Swallow »

Offline lkm

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #8 on: 08/31/2013 07:35 pm »
I seem to recall that flying on Mars is like flying at 100000 ft on Earth, so if you want a spaceplane you'll need a big wing going very fast, much too fast to be able take off or land at.
If you have Mars colonists with a spaceplane then I think you can give yourself a high performance NTR to power it, with that you can just airbreath for near surface travel at supersonic speeds without using any stored propellant. For Take-off and going to orbit I  would suggest carbon monoxide and oxygen as it's easy to manufacture from the atmosphere powered by the engine and can be used chemically to power VTOL rockets while the CO on its own can be used with the NTR when it's time to go orbital.

I would guess that it would look like a large blended-wing-body with large air inlets on the underside along with an array of take-off rockets, however flying on Mars is hard so I'm probably totally wrong. Either way take-off and landings are the hard part for this and any sort of tail sitter would probably be easier. But not cooler.

Offline gbaikie

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #9 on: 08/31/2013 08:30 pm »
I seem to recall that flying on Mars is like flying at 100000 ft on Earth, so if you want a spaceplane you'll need a big wing going very fast, much too fast to be able take off or land at.
Yeah, similar to 100000 ft.
But it seems you would have ground effect on Mars:

"When an aircraft is flying at an altitude that is approximately at or below the same distance as the aircraft's wingspan or helicopter's rotor diameter, there is, depending on airfoil and aircraft design, an often noticeable ground effect. This is caused primarily by the ground interrupting the wingtip vortices and downwash behind the wing. When a wing is flown very close to the ground, wingtip vortices are unable to form effectively due to the obstruction of the ground. The result is lower induced drag, which increases the speed and lift of the aircraft."
http://en.wikipedia.org/wiki/Ground_effect_%28aircraft%29

One could also have different airports on Mars than we have on Earth- one way they could be different is the airport could increase local air density for landings. Or instead of a concrete paving and wheels, it could be water, or ice and skies.

Offline joek

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #10 on: 08/31/2013 09:36 pm »
I seem to recall that flying on Mars is like flying at 100000 ft on Earth, so if you want a spaceplane you'll need a big wing going very fast, much too fast to be able take off or land at.

However, on Mars you require only 38% of Earth-equivalent lift, and atmospheric density is a bit higher than at Earth-equivalent pressure.  On the other hand, the speed of sound is significantly lower on Mars, and temperature fluctuations create significant variance in atmospheric density.  In short, air transport may be feasible for light payloads (and there are plenty of NASA studies that suggest such), but likely a significant challenge for what we would consider typical human or cargo transport.

Offline lkm

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #11 on: 08/31/2013 10:07 pm »
I seem to recall that flying on Mars is like flying at 100000 ft on Earth, so if you want a spaceplane you'll need a big wing going very fast, much too fast to be able take off or land at.
Yeah, similar to 100000 ft.
But it seems you would have ground effect on Mars:

"When an aircraft is flying at an altitude that is approximately at or below the same distance as the aircraft's wingspan or helicopter's rotor diameter, there is, depending on airfoil and aircraft design, an often noticeable ground effect. This is caused primarily by the ground interrupting the wingtip vortices and downwash behind the wing. When a wing is flown very close to the ground, wingtip vortices are unable to form effectively due to the obstruction of the ground. The result is lower induced drag, which increases the speed and lift of the aircraft."
http://en.wikipedia.org/wiki/Ground_effect_%28aircraft%29

One could also have different airports on Mars than we have on Earth- one way they could be different is the airport could increase local air density for landings. Or instead of a concrete paving and wheels, it could be water, or ice and skies.

As fun as a Mars ekranoplan might be they're not traditionally flown over land for, I suspect, good reason. Now a Mars hovercraft, a nuclear Mars hovercraft, might be more successful for cool surface travel. However OT.

I seem to recall that flying on Mars is like flying at 100000 ft on Earth, so if you want a spaceplane you'll need a big wing going very fast, much too fast to be able take off or land at.

However, on Mars you require only 38% of Earth-equivalent lift, and atmospheric density is a bit higher than at Earth-equivalent pressure.  On the other hand, the speed of sound is significantly lower on Mars, and temperature fluctuations create significant variance in atmospheric density.  In short, air transport may be feasible for light payloads (and there are plenty of NASA studies that suggest such), but likely a significant challenge for what we would consider typical human or cargo transport.

I've actually read a few papers on Mars rotor craft, essentially incredibly light construction, very large rotors and greatly limited by the need to not cause a huge brown out on take-off  due to all the dust. Basically whether by rotor or wing take-off and landing seems like a huge challenge, however nothing about "martian spaceplane" seems like it would be anywhere close to easy, which is why I suggested an NTR because it at least solves the power problem and can't really make the rest any harder than it already is.

Offline Nilof

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #12 on: 08/31/2013 11:59 pm »
While we're at it, what about spaceplanes on Titan? I know I'm derailing the topic a bit, but unlike on Mars where flying is hard, flying on Titan is rather easy with a very low gravity and a high surface pressure.

The Delta-V requirements are very low(escape velocity is 2.6 km/s), to the point where losses to drag would probably be very significant compared to the delta-v needed when outside of the atmosphere. You have enough extra mass to strap on a second set of engines to get out of the atmosphere, and a pair of ducted fans might help.

On the other hand, the gravity is so low that actual areodynamic lift as a means to convert kinetic energy into potential energy using wings isn't actually that useful compared to simply pointing your engines straight up to minimize drag losses. As a result you end up with something similar to the Roton instead.
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline KelvinZero

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #13 on: 09/01/2013 12:32 am »
Quote
Why would you insist on aircraft-like operations in an environment so unsuited for it?

Several reasons. A horizontal vehicle arrangement is more stable as well as being easier to load and unload. Because NASA has a proposed the used of martian gliders and other airborne probes I surmised that a Lifting-body or blended-wing design might provide a meaningful amount of lift while providing an excess amount of volume that I could fill with propellant. Likewise, spaceplanes are cool.

Hi, have you seen the DTAL lunar lander design?
That has horizontal landing and definitely has a cool factor because it is practically the eagle from space 1999.

http://www.nasaspaceflight.com/2006/09/lockheed-martin-lunar-landers-revealed/

Perhaps there could be something like that for mars with a bit of a lifting body shape as well. I guess that would look like a very stubby plane.

Offline Andrew_W

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #14 on: 09/01/2013 01:01 am »
The March 1990 issue of Analog has an article by Zubrin "Nuclear Rocketry Using Indigenous Propellants: The Key To The Solar System." Has a depiction of a Mars lander that looks like a streamlined Shuttle Orbiter capable of vertical landing.
I confess that in 1901 I said to my brother Orville that man would not fly for fifty years.
Wilbur Wright

Offline Archer

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #15 on: 09/01/2013 03:01 pm »
Almost any existing second stage is capable of inserting itself into orbit from the Martian surface. Add a heat shield and parachutes so it could re-enter and land like Curiosity.

I would also try using CO as propellant. Much easier to manufacture than CH4 let alone H2.
The future is better than the past. Despite the crepehangers, romanticists, and anti-intellectuals, the world steadily grows better because the human mind, applying itself to environment, makes it better. With hands...with tools...with horse sense and science and engineering. (c) R. A. Heinlein

Offline ARD

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #16 on: 09/01/2013 03:32 pm »
If one is going for chemical engines, I'd suggest LOX/methylacetylene rather than LOX/CH4.  Apparently, it's got comparable Isp to methane, but more dense, and liquid at ambient temperature (http://www.dunnspace.com/alternate_ssto_propellants.htm). 

Offline Hershey

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Re: Sci-Fi World Building: Design a martian spaceplane
« Reply #17 on: 09/04/2013 11:49 pm »
The March 1990 issue of Analog has an article by Zubrin "Nuclear Rocketry Using Indigenous Propellants: The Key To The Solar System." Has a depiction of a Mars lander that looks like a streamlined Shuttle Orbiter capable of vertical landing.

Oh, you mean this?

caption: NIMF rocketplane. (Artwork Robert Murray, courtesy Lockheed Martin) [case for mars, gallery plates]

"Nuclear rocket using indigenous Martian fuel" program.

Paraphrasing from Case for Mars:
"Need to carry outbound and inbound fuel limited max range of chemical rockets on Mars to 4000 km. So I invented NIMF. CO2 is compressed (condensed?), stored on landing, heated by NTR for exhaust. Low energy cost for propellant, <0.3 kWhe/kg. Little need for onboard electric power nor chemical synthesis gear. 260 isp. "

Comments: It's hard to tell from the blurry scan, but the ballistic nimf is about 10m wide by 23m or so tall. Between the left landing legs is a small unpressurized rover. Between the right landing legs is a small one-person elevator that fits into the depression in the top right, which leads to a small hab inside, complete with what appears to be a very comfortable chair.
« Last Edit: 09/06/2013 04:35 am by Hershey »

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