Author Topic: Space Exploration Vehicle Concept  (Read 108210 times)

Offline Mark S

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Re: Space Exploration Vehicle Concept
« Reply #140 on: 11/19/2015 06:44 PM »
A recent paper on modular exploration vehicles and habitats was published by A.S. Howe of JPL, attached is the document and one of the concepts for a modular lander.

That thing's really gonna move when they light up those four side-slung SSMEs. :)


Offline BrightLight

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Re: Space Exploration Vehicle Concept
« Reply #141 on: 11/19/2015 07:11 PM »
A recent paper on modular exploration vehicles and habitats was published by A.S. Howe of JPL, attached is the document and one of the concepts for a modular lander.

That thing's really gonna move when they light up those four side-slung SSMEs. :)
I don't recall seeing anything about using SSME's, however there is a Evolvable Mars Campaign (EMC) lander team looking at engine options. Google Evolvable Mars Campaign and Technology Development by Jason Crusan, Director, Advanced Exploration Systems Division, Human Exploration and Operations Mission Directorate November 4, 2015
« Last Edit: 11/19/2015 07:15 PM by BrightLight »

Offline redliox

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Re: Space Exploration Vehicle Concept
« Reply #142 on: 11/19/2015 07:24 PM »
A recent paper on modular exploration vehicles and habitats was published by A.S. Howe of JPL, attached is the document and one of the concepts for a modular lander.

There's also mention of 'habitank' concepts in it, which essentially reuses fuel tanks for empty habitats after.  If there's a simple way to do it that would be a lovely way to deliver useful hardware to either Mars or Luna.
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Offline NovaSilisko

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Re: Space Exploration Vehicle Concept
« Reply #143 on: 11/19/2015 07:25 PM »
A recent paper on modular exploration vehicles and habitats was published by A.S. Howe of JPL, attached is the document and one of the concepts for a modular lander.

That thing's really gonna move when they light up those four side-slung SSMEs. :)
I don't recall seeing anything about using SSME's

(he was joking due to the engines' large size and ribbed construction)

Offline Zed_Noir

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Re: Space Exploration Vehicle Concept
« Reply #144 on: 11/19/2015 08:30 PM »

That thing's really gonna move when they light up those four side-slung SSMEs. :)
I don't recall seeing anything about using SSME's

(he was joking due to the engines' large size and ribbed construction)

Kinda like the nozzle bell on the Apollo service module in size.

Offline NovaSilisko

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Re: Space Exploration Vehicle Concept
« Reply #145 on: 11/19/2015 08:34 PM »

That thing's really gonna move when they light up those four side-slung SSMEs. :)
I don't recall seeing anything about using SSME's

(he was joking due to the engines' large size and ribbed construction)

Kinda like the nozzle bell on the Apollo service module in size.

Yeah, or the Apollo descent engine with its extended nozzle, which mostly ended up being hidden inside the descent stage structure.

I'd be concerned about debris kicked up by that design, though. With Apollo you had the whole descent stage shielding you in addition to the fact the whole thing was slightly elevated. This, though, is right against the ground, and looks like you might need some sort of shielding to protect against flying pebbles.
« Last Edit: 11/19/2015 08:36 PM by NovaSilisko »

Offline the_other_Doug

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Re: Space Exploration Vehicle Concept
« Reply #146 on: 11/20/2015 02:19 AM »

That thing's really gonna move when they light up those four side-slung SSMEs. :)
I don't recall seeing anything about using SSME's

(he was joking due to the engines' large size and ribbed construction)

Kinda like the nozzle bell on the Apollo service module in size.

Yeah, or the Apollo descent engine with its extended nozzle, which mostly ended up being hidden inside the descent stage structure.

I'd be concerned about debris kicked up by that design, though. With Apollo you had the whole descent stage shielding you in addition to the fact the whole thing was slightly elevated. This, though, is right against the ground, and looks like you might need some sort of shielding to protect against flying pebbles.

Also, keep in mind the characteristics of plume impingement.  With one big engine, the plume hits the surface and all the particles it picks up and ejects go out radially, along with the plume.  Apollo proved that this dust sheet stayed low to the ground in the airless environment, as well, especially near the lander.  So, a single engine doesn't tend to kick dust or pebbles right back up into the lander.

However, the plumes from four big engines will develop a chaotic upflow where they impinge upon each other as each is deflected radially while the lander approaches the surface.  Granted, the chaotic upflow won't be moving nearly as fast as the exit velocity of the gasses coming out of the nozzles, but I bet it will toss a lot of dust and pebbles at potentially dangerous velocities up into the underside of the lander.

If you look at the final moments of the descent video from Chang'e 3, you can see several semi-static features developing in the surface impingement where, it appears to me, the relatively low-thrust descent thrusters were interacting.  With higher-thrust engines, I bet those features turn into upflow regions.

It's not a show-stopper, but if you want to make the landers re-usable, and/or use the same engines to lift back off the surface that you used to land with, you're going to have to run a lot of very complex simulations to determine how much, and where, you'll need to provide shielding on your lander and in and around your engine structures to protect from potentially supersonic dust particles and pebbles fountaining up into the bottom of your lander.  I mean, how many rocket engines work really good after they're sandblasted?
« Last Edit: 11/20/2015 02:26 AM by the_other_Doug »
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Online A_M_Swallow

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Re: Space Exploration Vehicle Concept
« Reply #147 on: 11/21/2015 10:33 PM »

Yeah, or the Apollo descent engine with its extended nozzle, which mostly ended up being hidden inside the descent stage structure.

I'd be concerned about debris kicked up by that design, though. With Apollo you had the whole descent stage shielding you in addition to the fact the whole thing was slightly elevated. This, though, is right against the ground, and looks like you might need some sort of shielding to protect against flying pebbles.

Can many of the debris problems be avoided by keeping the engines at least 15 feet off the ground? This also simplifies launch problems due to not having a frame trench on the Moon and Mars.

Offline Ben the Space Brit

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Re: Space Exploration Vehicle Concept
« Reply #148 on: 12/30/2015 02:12 PM »
My idea is a U-shaped thrust structure/truss with the rover driving out of the middle and backing back into 'the slot' for its return flight up. The rover could be replaced in the truss with a cargo hopper or a pressurised hab for a multi-cargo launch mission.

Engines would be LM-derived hypergolic mounted on the truss that point outwards at a slight angle to stop too much debris being deflected back towards the rover. The truss would also mount the RCS and landing sensors thus minimising the redundant weight carried by the Rover.

The docking adapter would be a 'kiss' front-mounted unit on the front of the Rover for either docking with an Orion or Dragon or hard-mating with a landed hab.
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Offline Oli

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Re: Space Exploration Vehicle Concept
« Reply #149 on: 02/17/2016 03:38 AM »

It's a shame NASA isn't developing the MMSEV instead of Orion. So many potential applications: Asteroids, Phobos Taxi, Lunar Lander etc. It could also serve as a LEO-L2 Taxi if refueled at L2 since its relatively lightweight.

Online A_M_Swallow

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Re: Space Exploration Vehicle Concept
« Reply #150 on: 02/17/2016 05:56 AM »

It's a shame NASA isn't developing the MMSEV instead of Orion. So many potential applications: Asteroids, Phobos Taxi, Lunar Lander etc. It could also serve as a LEO-L2 Taxi if refueled at L2 since its relatively lightweight.

Could a modified Centaur get a MMSEV massing 4-5 tons from LEO to EML-2?
That is a delta-v of about 3.43 km/s. Then be refuelled for the return trip.

The return fuel could be sent to the EML-2 depot on a SEP tug.

Offline Oli

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Re: Space Exploration Vehicle Concept
« Reply #151 on: 02/17/2016 08:22 AM »

It's a shame NASA isn't developing the MMSEV instead of Orion. So many potential applications: Asteroids, Phobos Taxi, Lunar Lander etc. It could also serve as a LEO-L2 Taxi if refueled at L2 since its relatively lightweight.

Could a modified Centaur get a MMSEV massing 4-5 tons from LEO to EML-2?
That is a delta-v of about 3.43 km/s. Then be refuelled for the return trip.

The return fuel could be sent to the EML-2 depot on a SEP tug.

With Centaur-like mass fraction a 7.4t hydrolox stage could boost a 5t payload to 3.5km/s.

A ~15t hypergolic pressure-fed stage will do as well though. You probably want something very reliable for the job.
« Last Edit: 02/17/2016 08:22 AM by Oli »

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