Author Topic: A Fully-Reusable Mars Surface Architecture  (Read 8021 times)

Offline simonbp

I had the idea today for a fully-reusable Mars surface architecture. It's not exactly easy or realistic, but still fun to think about...

Surface Elements:

* Unpressurized rover housing ISRU equipment/tankage and small nuclear reactor
* Pressurized rover/hab
* Reusable single-stage CH4/O2 lander

In-space Elements:

* Unpressurized rover + Disposable SEP stage
* Pressurized rover + Disposable SEP stage
* Lander + Disposable SEP stage
* Mars Transfer Vehicle (w/reusable SEP) + Landing CH4/O2 + Return Capsule

Launches for Expedition 1:

1. Unpressurized rover + Disposable SEP stage
2. Pressurized rover + Disposable SEP stage
3. Lander + Disposable SEP stage
4. Mars Transfer Vehicle (w/reusable SEP) (to LEO, slow spiral to EML2)
5. Landing CH4/O2 + SEP prop + Return Capsule (Direct to EML2)

Launches for Expedition 2+ (assuming full recovery):

1. Landing CH4/O2 + SEP prop + Return Capsule (Direct to EML2)

Sequence of events:

1. At first launch window, the Unpressurized Rover, Pressurized Rover, and Lander (with minimal propellant) are all launched on Heavy Lift Vehicles (HLVs) to LEO. They then perform a slow spiral to a Mars trajectory, arriving at Mars a year later. The rovers directly enter the Martian atmosphere and land. The lander uses its engines to capture into a High Mars Orbit (HMO).

2. Around when the surface elements arrive at Mars, the Mars Transfer Vehicle is launched (unmanned) on an HLV and spirals out to EML2. It remains in an EML2 halo orbit until the launch window opens. Then, a final HLV launches the crew in the return capsule attached to a CH4/O2/Xe tanker direct to EML2. They dock with the MTV, transfer the propellant, discard the tanker, and depart to Mars.

3. The MTV arrives in HMO and docks with the Lander. The propellant and crew are transferred to the Lander, and the Lander lands near the rovers. Since the other two surface elements are mobile, the landing need not be extremely accurate. Humans are on Mars.

4. The crew EVAs to the Pressurized Rover, and spends the rest of the surface mission exploring the area around the landing site. In case of Pressurized Rover problems, the Unpressurized Rover can find and retrieve the other rover and crew. Once they have completed the surface mission, the crew transfer the ISRU CH4/O2 from the Unpressurized Rover to the Lander, and depart back to the waiting MTV.

5. The Lander rendezvouses with the MTV, and the crew transfer over. The Lander is left in HMO, and the MTV departs for Earth. Meanwhile, the two rovers begin to autonomously drive to the landing site of the next Expedition.

6. The Crew Return Vehicle detaches from the MTV early, and directly reenters the Earth's atmosphere. The MTV, meanwhile, begins a complex dance to return it to EML2. Once there, the system has reset, and is ready for the next Expedition.

7. The Expedition 2 crew launches on an HLV, and the process repeats. Additional rovers/equipment could be sent to Mars as well, but are not required.

Required Technology:

1. Large SEP (and/or NEP) systems
2. Large Mars EDL systems
3. In-space fission reactor (at least for ISRU, possibly for MTV)
4. Large-scale Mars ISRU
5. Long-lived/-distance Mars mobility systems
6. HLV of some variety
« Last Edit: 09/17/2010 12:16 AM by simonbp »

Offline A_M_Swallow

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #1 on: 09/17/2010 01:56 AM »
Why are the SEP disposable?
If they fly back to EML1/2 a second trip should be possible.

Offline simonbp

Re: A Fully-Reusable Mars Surface Architecture
« Reply #2 on: 09/18/2010 04:43 AM »
Why are the SEP disposable?
If they fly back to EML1/2 a second trip should be possible.

Two reasons:

1. It's easier. The two rovers are sent on entry trajectories, and the lander very close to one. Therefore, it's going to take a lot of prop to get them back to Earth. The MTV has to head back towards Earth anyways, and is refueled at EML2 before departure, so it's much more justifiable to reuse.

2. It's not necessary to reuse them. If you have full recovery, you never need more than the three initial unmanned flights. In reality, you probably end up sending another lander or rover in the future, but the unmanned flight rate after the initial mission will be very low.

It's also important not to mentally merge EML1 and EML2, as dynamically, they are very different beasts. EML2 is the easiest place to leave the Earth-Moon system from, and nearly all low-thrust trajectories to escape from EML1 pass through EML2. So, best just to rendezvous at L2 and be done with it.
« Last Edit: 09/18/2010 04:45 AM by simonbp »

Offline Patchouli

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #3 on: 09/18/2010 06:25 AM »
Why are the SEP disposable?
If they fly back to EML1/2 a second trip should be possible.

Two reasons:

1. It's easier. The two rovers are sent on entry trajectories, and the lander very close to one. Therefore, it's going to take a lot of prop to get them back to Earth. The MTV has to head back towards Earth anyways, and is refueled at EML2 before departure, so it's much more justifiable to reuse.

2. It's not necessary to reuse them. If you have full recovery, you never need more than the three initial unmanned flights. In reality, you probably end up sending another lander or rover in the future, but the unmanned flight rate after the initial mission will be very low.

It's also important not to mentally merge EML1 and EML2, as dynamically, they are very different beasts. EML2 is the easiest place to leave the Earth-Moon system from, and nearly all low-thrust trajectories to escape from EML1 pass through EML2. So, best just to rendezvous at L2 and be done with it.

How about adding some instruments to the SEP stage and have it act as a deep space probe after delivering it's payload.

The asteroid belt or even Jupiter might be reachable even though there is not enough propellant to return it to Earth.
« Last Edit: 09/18/2010 06:26 AM by Patchouli »

Offline simonbp

Re: A Fully-Reusable Mars Surface Architecture
« Reply #4 on: 09/18/2010 06:31 AM »
How about adding some instruments to the SEP stage and have it act as a deep space probe after delivering it's payload.

As I said, they're on entry trajectories, and will enter Mars's atmosphere. Destructively.

Also, instruments add cost and remove payload mass; just not worth it.

Offline Robotbeat

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #5 on: 09/18/2010 06:35 AM »
How about adding some instruments to the SEP stage and have it act as a deep space probe after delivering it's payload.

As I said, they're on entry trajectories, and will enter Mars's atmosphere. Destructively.

Also, instruments add cost and remove payload mass; just not worth it.
It's an SEP stage. Doesn't take that much delta-v to avoid hitting Mars. Then, it enters a solar orbit and could make its way back toward Earth. Kind of like a little cycler.
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Offline Patchouli

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #6 on: 09/18/2010 06:38 AM »
How about adding some instruments to the SEP stage and have it act as a deep space probe after delivering it's payload.

As I said, they're on entry trajectories, and will enter Mars's atmosphere. Destructively.

Also, instruments add cost and remove payload mass; just not worth it.

I figured the stage could separate and perform an avoidance maneuver a few weeks before entry.
Unless it's also supplying keep alive power to the payload the whole time.
« Last Edit: 09/18/2010 06:39 AM by Patchouli »

Offline simonbp

Re: A Fully-Reusable Mars Surface Architecture
« Reply #7 on: 09/18/2010 05:01 PM »
It's an SEP stage. Doesn't take that much delta-v to avoid hitting Mars. Then, it enters a solar orbit


This I'll agree with.

Quote
and could make its way back toward Earth. Kind of like a little cycler.

This is hard. It takes a lot of energy to turn around and head back towards Earth. Especially as the small delta v to avoid Mars means that you're going to get a wicked gravity assist in a direction away from Earth. The MTV gets around this by capturing into a very high circular orbit (~10-20% of Mars's Hill radius, for sake of argument). Having the unmanned SEP stages capture into a similar orbit and then wait for the next opportunity to return to Earth is possible, but costs a lot of propellant, the mass for which has to be stolen from the payload.

I do find it amusing that you guys are harping on one of the afterthought aspects of this plan. IMHO, the mobile/reusable hab and ISRU are the much cooler features...

Offline Patchouli

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #8 on: 09/19/2010 12:19 AM »

This is hard. It takes a lot of energy to turn around and head back towards Earth. Especially as the small delta v to avoid Mars means that you're going to get a wicked gravity assist in a direction away from Earth.

I was thinking about that aspect when I figured could the SEP stage be made to do some science in the asteroid belt or near Jupiter before it freezes to death.

On the hab I wonder if ATHLETE could be integrated into the hab as the landing gear.

Maybe use the sky crane system from MSL and the mobile hab can start driving after touch down.

Or just have it attached to the first payloads so they can be reused to assemble the base.
« Last Edit: 09/19/2010 12:21 AM by Patchouli »

Offline simonbp

Re: A Fully-Reusable Mars Surface Architecture
« Reply #9 on: 09/19/2010 03:10 AM »
On the hab I wonder if ATHLETE could be integrated into the hab as the landing gear.

Maybe use the sky crane system from MSL and the mobile hab can start driving after touch down.

ATHLETE would be a good option for the unpressurized rover. The pressurized rover should probably be something more like the JSC LER, but sized for four people. A large skycrane would be useful for landing the rovers, potentially with some type of inflatable heatshield.

The bigger EDL question was how to pull off a single-stage, reusable Mars lander...

Offline alexw

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #10 on: 09/19/2010 06:28 AM »
The bigger EDL question was how to pull off a single-stage, reusable Mars lander...
    Nearly all supersonic retropropulsion? Needs some kind of heat shield, perhaps heavy and multiple use, but some kind of legs need to deploy around or through it. Maybe the legs are behind pop-off panels, and the panels get replaced in HMO via EVA, with new ones brought from Earth?
           -Alex

Offline simonbp

Re: A Fully-Reusable Mars Surface Architecture
« Reply #11 on: 09/19/2010 07:00 AM »
Well, the TPS could Shuttle-like. The main issue with the silica tiles is water absorption, which is not exactly a problem on Mars, though dust may be. And aircraft-style retractable gear should be OK; in Mars gravity, gear doesn't need to be that strong.

Supersonic retrorockets do worry me more. Probably the best way around is a deployable airbrake to get the speed just under Mach 1, something like the old TGV Michelle-B (or the recent speculation of New Shepard)...
« Last Edit: 09/19/2010 07:04 AM by simonbp »

Offline Nathan

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #12 on: 09/19/2010 07:01 AM »
On the hab I wonder if ATHLETE could be integrated into the hab as the landing gear.

Maybe use the sky crane system from MSL and the mobile hab can start driving after touch down.

ATHLETE would be a good option for the unpressurized rover. The pressurized rover should probably be something more like the JSC LER, but sized for four people. A large skycrane would be useful for landing the rovers, potentially with some type of inflatable heatshield.

The bigger EDL question was how to pull off a single-stage, reusable Mars lander...

Biconic, no more than ten tonnes. No chutes.
Given finite cash, if we want to go to Mars then we should go to Mars.

Offline MickQ

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #13 on: 09/23/2010 07:16 AM »
Simon.

What do you propose doing with the CH4/O2/Xe tanker after the MTV departs for Mars ?  I know you plan to discard it, but how ?  Leave it at EML2 for recovery or maybe a slow SEP or VASIMR to somewhere else ?

How about a slow trajectory to Mars orbit to be used as a future prop depot ?

Mick.

Offline Robotbeat

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Re: A Fully-Reusable Mars Surface Architecture
« Reply #14 on: 11/15/2010 01:34 PM »
On the hab I wonder if ATHLETE could be integrated into the hab as the landing gear.

Maybe use the sky crane system from MSL and the mobile hab can start driving after touch down.

ATHLETE would be a good option for the unpressurized rover. The pressurized rover should probably be something more like the JSC LER, but sized for four people. A large skycrane would be useful for landing the rovers, potentially with some type of inflatable heatshield.

The bigger EDL question was how to pull off a single-stage, reusable Mars lander...
Yeah, I'm a big fan of ATHLETE and the skycrane EDL concept. JPL should be in charge of the pressurized rover, IMHO. They have all the experience in the world for driving around the Red Planet.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

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