Author Topic: Mars Orbital mission with only DSH and Orion  (Read 12516 times)

Offline ncb1397

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Mars Orbital mission with only DSH and Orion
« on: 06/04/2016 05:18 PM »
Basic components:

Orion with upgraded SM
40 mT fuel
9 mT SM
10 mT CM
59 mT total
300 isp hypergolic engine

DSH
5 mT xenon
5 mT solar array
15 mT habitation, docking ports and water/fuel tanks
5 mT food and logitics
5 mT water for shielding and drinking
total: 35 mT
3000 isp electric engine

Interplanetary spacecraft is 3 orions as chemical tugs and 1 DSH. TMI, orbital insertion at mars and TEI is done chemically with Orion. Total mass is 212 mT.

The 3 orions provide the following delta V to yield the 3.1 km/s total mission propulsive delta v for ~GTO -> Mars high elliptical orbit -> Earth doing a direct entry at Earth.

1st orion(expended after fuel used up): 212 mT/ 172 mT mass ratio for delta V of 615 m/s
2nd orion(expended after fuel used up):153 mT/ 113 mT mass ratio for delta V of 891 m/s
3rd orion(kept in stack after burn to do earth re-entry): 94 mT / 54 mT mass ratio for delta V of 1630 m/s
total delta V: 3136 m/s

The mission would require 4 launches(1 DSH, 3 Orions) to sub-GTO on an SLS 1B. They will be auto-docked together with the last launch carrying crew. DSH would use SEP to raise orbit to an elliptical earth orbit higher energy than GTO before departure. The Orion tugs can do all the mission maneuvers chemically from GTO, but starting from a higher orbit adds margins. Additionally, the barely used SEP system adds margins and allows for some maneuvering in mars orbit.

Some upgrades possible are a methane/oxygen cryogenic service module for orion which will allow for higher isp and supplying oxygen, water, heat and power from the propellant tanks for contingencies or mission planning. The ideal would be a hydrogen/oxygen cryogenic SM with fuel cells but ZBO may not be technically feasible. Additionally, the DSH could be upgraded for nuclear power and NEP or upgraded with better isp electric engines or higher specific power solar panels.

A quick picture of the stack configuration once configured for interplanetary flight:
https://docs.google.com/drawings/d/1b_ahutB8E5n7fBE4IIswQE9UoqEu5nmBWCJy4HZjFlY/edit?usp=sharing
« Last Edit: 06/04/2016 05:20 PM by ncb1397 »

Offline redliox

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Re: Mars Orbital mission with only DSH and Orion
« Reply #1 on: 06/04/2016 08:02 PM »
Although improving Orion's SM is a good idea, 3 Orions plus a DSH isn't going to suffice. I've crunched a few numbers before with it; Orion is a leadweight beyond Earth orbit. Using electric propulsion to put the DSH in high orbit is good as would be using it en route to Mars, but SEP is also too sluggish to sufficiently help in larger maneuvers.  Using 3 Orions versus just 2 exclusively near Earth isn't efficent enough.
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Offline Chilly

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Re: Mars Orbital mission with only DSH and Orion
« Reply #2 on: 06/07/2016 03:29 PM »
I ranted about something along these lines at my own blog a couple of months ago (https://chilesfiles.wordpress.com/2016/04/22/halfway-to-nowhere/#more-2489). I'd dearly love to see NASA take advantage of the 2021 free-return window as outlined by the Inspiration Mars crowd. If we can't afford to launch SLS much more than once a year, then let's make it count for something before the whole thing is steamrolled into obsolescence by the private sector.
A manned flyby of Venus and Mars would be an audacious and extremely valuable proof-of-concept mission. There's a golden opportunity here for a one-off, Apollo 8-style home run if we only had the stones to pursue it. But that would require focused leadership and political will to see it through over a couple of election cycles.
Therefore, it won't happen. But damn if it wouldn't be glorious.
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Offline Khadgars

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Re: Mars Orbital mission with only DSH and Orion
« Reply #3 on: 07/11/2016 10:58 PM »
What about doing this for the EVME Free Return Trajectory in 2021? 

Offline Chilly

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Re: Mars Orbital mission with only DSH and Orion
« Reply #4 on: 07/11/2016 11:01 PM »
Pretty sure that's what I was advocating...
Those who can't do, write.

Offline guckyfan

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Re: Mars Orbital mission with only DSH and Orion
« Reply #5 on: 07/13/2016 01:25 PM »
The return speed for the free return trajectory is quite high. Higher than a normal Mars return. Pretty sure Orion cannot handle it for a direct EDL. Could Orion brake to capture and then reach L1 without service module?

Online brickmack

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Re: Mars Orbital mission with only DSH and Orion
« Reply #6 on: 07/15/2016 11:15 PM »
Orion is only rated for 1 year in space anyway, even if it could survive reentry from a Mars return trajectory its not certified to carry people on such a long duration mission. This is why most of the notional Mars proposals so far using SLS leave Orion behind in cislunar orbit

Online KelvinZero

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Re: Mars Orbital mission with only DSH and Orion
« Reply #7 on: 07/16/2016 07:04 AM »
Instead of generic ion engines, how about multiple instances of the SEP tug? I have seen images implying it would stack nicely and even is designed to do so. I think this is more in line with the OP's goal of working with what we have (though I admit the term 'have' is a bit flexible here :) )

We could have the DSH being tested out for a few years in high lunar orbit. We could have several SEP tugs visiting asteroids or whatever, and perhaps time the mars orbit mission for the point at which we have most trust in the hardware: not too new, not to old.

My layman's feeling is that a single orion would be best, just for the initial push with whatever propellant it can reasonably have on arrival at the DSH, then keep the command module and perhaps immediately dump the service module. Use electric thrust for the rest and aim for Deimos due to it being easier in terms of delta-v.

Perhaps the DSH orbit could be nudged into a near earth approach before the mission begins to exploit Oberth effect for this one small burn.

About this Orion one year and speed of earth reentry issue, how big a job is that to fix? Seems to me that if we are going to build that Orion thing we should at least have an upgrade path planned. It doesn't need to be the first Orion that flies, but this would have to be a few years later (after the DSH and SEP tug shakedown mentioned)
« Last Edit: 07/16/2016 07:05 AM by KelvinZero »

Offline A_M_Swallow

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Re: Mars Orbital mission with only DSH and Orion
« Reply #8 on: 07/16/2016 06:01 PM »
Instead of generic ion engines, how about multiple instances of the SEP tug? I have seen images implying it would stack nicely and even is designed to do so. I think this is more in line with the OP's goal of working with what we have (though I admit the term 'have' is a bit flexible here :) )

We could have the DSH being tested out for a few years in high lunar orbit. We could have several SEP tugs visiting asteroids or whatever, and perhaps time the mars orbit mission for the point at which we have most trust in the hardware: not too new, not to old.

My layman's feeling is that a single orion would be best, just for the initial push with whatever propellant it can reasonably have on arrival at the DSH, then keep the command module and perhaps immediately dump the service module. Use electric thrust for the rest and aim for Deimos due to it being easier in terms of delta-v.

Perhaps the DSH orbit could be nudged into a near earth approach before the mission begins to exploit Oberth effect for this one small burn.

About this Orion one year and speed of earth reentry issue, how big a job is that to fix? Seems to me that if we are going to build that Orion thing we should at least have an upgrade path planned. It doesn't need to be the first Orion that flies, but this would have to be a few years later (after the DSH and SEP tug shakedown mentioned)

The problem with that is the Orion Service Module supplies the crew with oxygen and water. The Command Module can only support life for a few hours.
https://en.wikipedia.org/wiki/Orion_Service_Module

Online KelvinZero

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Re: Mars Orbital mission with only DSH and Orion
« Reply #9 on: 07/16/2016 11:16 PM »
The problem with that is the Orion Service Module supplies the crew with oxygen and water. The Command Module can only support life for a few hours.
https://en.wikipedia.org/wiki/Orion_Service_Module
That is enough, isn't it? I was imagining all/most of the lifesupport on the DSH, and direct return to earth.

I admit I really hadn't been keeping up with what this service module is. I also hadn't thought about whether whatever tiny thrusters the command module has are enough to arrange it to enter the earth's atmosphere while the DSH passes by.

What is it that limits the Orion to one year in space? I imagined that fundamental problems were more likely in the inaccessibility of the service module, and that command module issues could be solved without massive redesign?

Offline Bob Shaw

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Re: Mars Orbital mission with only DSH and Orion
« Reply #10 on: 07/16/2016 11:52 PM »
I ranted about something along these lines at my own blog a couple of months ago (https://chilesfiles.wordpress.com/2016/04/22/halfway-to-nowhere/#more-2489). I'd dearly love to see NASA take advantage of the 2021 free-return window as outlined by the Inspiration Mars crowd. If we can't afford to launch SLS much more than once a year, then let's make it count for something before the whole thing is steamrolled into obsolescence by the private sector.
A manned flyby of Venus and Mars would be an audacious and extremely valuable proof-of-concept mission. There's a golden opportunity here for a one-off, Apollo 8-style home run if we only had the stones to pursue it. But that would require focused leadership and political will to see it through over a couple of election cycles.
Therefore, it won't happen. But damn if it wouldn't be glorious.


I take your point, though the comparison to Apollo 8 is somewhat false; however, in view of the declared intent of SpaceX to not merely go to Mars, but to land a sort-of-human-rated spacecraft there within the next few years (SLS notwithstanding) it is probably too late to rescue SLS/Orion with a 'death or glory' shot. Wouldn't it be a nice demo, however, to have Red Dragon land on Mars and deploy a rover which was controlled in real-time by the crew of an Orion looping past Mars... ...but that won't happen.

Offline RonM

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Re: Mars Orbital mission with only DSH and Orion
« Reply #11 on: 07/17/2016 03:30 PM »
Interesting thing about all this Orion/SLS and MCT planning is the timeframe. SpaceX is planning BFS Mars missions in the 2020s, as early as 2024. NASA is planning Mars missions in the 2030s and 2040s. During the 2020s NASA will be conducting cislunar tests.

If SpaceX is successful, then NASA can join in on SpaceX missions to Mars and either cancel Orion/SLS or use it for lunar or asteroid missions.

If SpaceX fails to get BFS off the ground, then NASA can continue on with its Orion/SLS program.

If both organizations fail, we're just back to the status quo.

Both organizations should keep working on their projects and see what happens. We're in a better situation of someone getting to Mars than ever before.

Getting back to the OP, three Orion spacecraft on a single mission isn't practical. One SLS launch for the crew in an Orion and the other two launches can be propulsion modules.

Offline Arb

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Re: Mars Orbital mission with only DSH and Orion
« Reply #12 on: 07/17/2016 10:46 PM »
If SpaceX is successful, then NASA can ... either cancel Orion/SLS or use it for lunar or asteroid missions.

A nit but an important one. NASA cannot cancel SLS; only Congress can do that.


Offline tea monster

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Re: Mars Orbital mission with only DSH and Orion
« Reply #13 on: 07/17/2016 10:51 PM »
Instead of 3 Orions, why not have another ICPS for boost operations?

Offline RonM

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Re: Mars Orbital mission with only DSH and Orion
« Reply #14 on: 07/18/2016 02:21 AM »
If SpaceX is successful, then NASA can ... either cancel Orion/SLS or use it for lunar or asteroid missions.

A nit but an important one. NASA cannot cancel SLS; only Congress can do that.

Yes, thanks for pointing that out.

Online Zed_Noir

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Re: Mars Orbital mission with only DSH and Orion
« Reply #15 on: 07/18/2016 03:52 AM »
If SpaceX is successful, then NASA can ... either cancel Orion/SLS or use it for lunar or asteroid missions.

A nit but an important one. NASA cannot cancel SLS; only Congress can do that.

Yes, thanks for pointing that out.

Slightly OT query. If the SpaceX architecture works than who get the final say in who gets to ride along, since it will not be a NASA mission?



Online AncientU

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Re: Mars Orbital mission with only DSH and Orion
« Reply #16 on: 07/18/2016 03:53 PM »
How are we going to have even one human qualified Orion, a few SLS launches, or an SEP tug by 2021?
« Last Edit: 07/18/2016 03:55 PM by AncientU »
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Offline A_M_Swallow

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Re: Mars Orbital mission with only DSH and Orion
« Reply #17 on: 07/18/2016 05:11 PM »
How are we going to have even one human qualified Orion, a few SLS launches, or an SEP tug by 2021?

The back end of the Asteroid Redirect Robotic Mission (ARRM) spacecraft is a Solar Electric Propulsion (SEP) tug. This is due to be launched in December 2021. So by about 2021 NASA will be able to buy SEP tugs.

The tug design may need upgrading to reach human rating standards.

Offline Jim

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Re: Mars Orbital mission with only DSH and Orion
« Reply #18 on: 07/18/2016 05:26 PM »

The back end of the Asteroid Redirect Robotic Mission (ARRM) spacecraft is a Solar Electric Propulsion (SEP) tug. This is due to be launched in December 2021. So by about 2021 NASA will be able to buy SEP tugs.

The tug design may need upgrading to reach human rating standards.

NASA can buy SEP tugs now if it wants to.  See Dawn.


Offline A_M_Swallow

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Re: Mars Orbital mission with only DSH and Orion
« Reply #19 on: 07/18/2016 06:39 PM »

The back end of the Asteroid Redirect Robotic Mission (ARRM) spacecraft is a Solar Electric Propulsion (SEP) tug. This is due to be launched in December 2021. So by about 2021 NASA will be able to buy SEP tugs.

The tug design may need upgrading to reach human rating standards.

NASA can buy SEP tugs now if it wants to.  See Dawn.



Good machine Dawn. However its SEP is not a heavy.

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