Author Topic: ASAP on board with NASA's DSG as stepping stone to Mars  (Read 30114 times)

Offline Space Ghost 1962

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #40 on: 06/14/2017 05:28 PM »
Suggest we are past so much mass/ineffective ISS modules.

What do you most need in a DSG? Think about Mars arrival - what do you want at "base camp", to support surface descent/ascent/return ... that you don't want to carry along with you on DST. And ... a DSG whose logistics to maintain when idle (99% of the time) is least.

Mars robots have already a significant record accumulated of operation. A robotically maintained/resupplied/repaired station with longevity and substantial solar power/EP/"stationkeeping"/orbital maneuvering margin (to Phobos/Deimos) is the minimum, and the expectation of normal operation. Because that's where the basic economics of DSG operations would come from - nothing more than a glorified version of MAVEN/Curiosity, what we have there already, just with scaled up SEP and 5-10x longer life. And, if this basis module to the DSG were to start to deteriorate (like equipment on the ISS), you schedule your ground spare for flight immediately (and if it doesn't fail, it's a "hot" standby).

That's the minimum.

Next, likely you want an airlock / tools / "arm" for extraordinary repairs, meant to be used less than once a year, meaning not for  FRFs etc. Keeping this useful but constrained would be difficult (you'd likely incrementally "grow" this capability on every mission).

Propellant/consumables/components reserves for extraordinary needs/leaks/spoilage/whatever.

Docking capability for N > 3 vehicles (two plus automated resupply). In the worst, worst case, the ability to always gain access through robotic vehicle access would be preserved, potentially launched at unfavorable times and possibly through peculiar conditions/windows.

That's it.

Specifically, no hab and little persistent ECLSS/human volume, not much more than a capsule. Your transit vehicle is the one that needs that, the one that will be used longest, have the most wear/tear.

This is why such dumb notions as Bigelow modules are worst solutions ever. Your astros shouldn't spend anytime with DSG at all - that wears down a hard to reach/maintain asset for no gain. Stations are a really bad idea for exploration. Like rovers, we need to have exploration assets on the move at all times.

So DSG's cannot be a burden but instead refuge/repair/resupply/"plan B". Most of the time cold storage.

Spend your Bigelow module time/resources on exploration vehicles like landers/rovers/MMSEV's etc. Something that generates a research product, possibly part-time used HSF, rest robotic. Think different.

Leave the Bigelow module/etc to what they do best - resorts. Govt does not need to fund any Trump towers in space. That's not exploration - leave it to commercial space, where it always belonged.

Possibly research labs in space fit for materials/other research. Also a commercial activity past the ISS "one-shot".

Offline MATTBLAK

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #41 on: 06/14/2017 11:10 PM »
I too don't believe the Bigelow modules will do for a Gateway Module. They're far too unproven at this stage to rely on. But Gateway modules will have to be structurally robust - which would mean aluminum. I'd never advocate just plunking surplus ISS modules at Lagrange points - though the ISS modules are proven spacecraft hulls. Continually starting from a clean sheet design could bring up as many costly delays as it would new operational features and improvements. Double-edged sword, I guess.
« Last Edit: 06/14/2017 11:10 PM by MATTBLAK »
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Online envy887

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #42 on: 06/14/2017 11:32 PM »
I don't buy for a minute that aluminum vessels are structurally better than a well designed composite inflatable.

However, Bigelow habs are focused on habitable volume, which as pointed out above isn't the primary need in a DSG.

Offline MATTBLAK

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #43 on: 06/15/2017 12:04 AM »
I didn't say better - I said proven.
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Offline A_M_Swallow

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #44 on: 06/15/2017 07:19 AM »
I didn't say better - I said proven.

Operate a prototype gateway in LEO for a few years and composite inflatables will also be proven.

Offline MATTBLAK

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #45 on: 06/15/2017 08:03 AM »
Good! Let's see them get on with it then... I hope by 2021 & beyond, we're all still not waiting. Though I would urge us all not to have blind faith in any particular structural substance or configuration. Some people are treating composite and/or inflatable modules as a given - and suggesting anything else seems to make that same folk bizzarely upset. We'll just have to wait and see.
« Last Edit: 06/15/2017 11:50 PM by MATTBLAK »
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Offline su27k

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #46 on: 06/17/2017 04:33 AM »

To quote the article "“In terms of basic functionality, the DSG is being planned to support multiple NASA, commercial, and international objectives,” added the overview. “It would be designed for the deep space environment and would support a crew of 4 for total mission durations of up to 42 days with the Orion vehicle attached."

Please explain how is a 42 days ECLSS qualifies as long term life support?

After 10 visits that is 10 * 42 = 420 days. More than a year.

Where does 10 visits come from? There are only 6 Orion flights (EM-1 to 5 and EM-7) before DST one year shakedown mission, and only 4 Orion flights (EM-3 to 5 and EM-7) after Habitation Module is deployed, so you only gets to run ECLSS 4 * 42 = 168 days before you need to run ECLSS for a year. And you only run ECLSS 42 days a time, so you can't test whether it can be run continuously without breakdown.

A multi-year continuous ECLSS test can easily be done via ISS, so why run it in DSG? This is the whole problem with this DSG plan. If you want to test long term ECLSS then just focus on ECLSS, if you want to build DST then build it, drag DSG into it will only mean less funding for things actually matter.
« Last Edit: 06/17/2017 04:36 AM by su27k »

Offline Oli

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #47 on: 06/17/2017 08:10 AM »
This is the whole problem with this DSG plan. If you want to test long term ECLSS then just focus on ECLSS, if you want to build DST then build it, drag DSG into it will only mean less funding for things actually matter.

The point of DSG is to give SLS/Orion something to do until DST is ready. Experience gained is a bonus.

Offline TrevorMonty

This is the whole problem with this DSG plan. If you want to test long term ECLSS then just focus on ECLSS, if you want to build DST then build it, drag DSG into it will only mean less funding for things actually matter.

The point of DSG is to give SLS/Orion something to do until DST is ready. Experience gained is a bonus.
Plus international partners want it as it get them closer to moon.

Offline A_M_Swallow

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #49 on: 06/17/2017 10:09 AM »

To quote the article "“In terms of basic functionality, the DSG is being planned to support multiple NASA, commercial, and international objectives,” added the overview. “It would be designed for the deep space environment and would support a crew of 4 for total mission durations of up to 42 days with the Orion vehicle attached."

Please explain how is a 42 days ECLSS qualifies as long term life support?

After 10 visits that is 10 * 42 = 420 days. More than a year.

Where does 10 visits come from? There are only 6 Orion flights (EM-1 to 5 and EM-7) before DST one year shakedown mission, and only 4 Orion flights (EM-3 to 5 and EM-7) after Habitation Module is deployed, so you only gets to run ECLSS 4 * 42 = 168 days before you need to run ECLSS for a year. And you only run ECLSS 42 days a time, so you can't test whether it can be run continuously without breakdown.
{snip}
10 is a nice simple round number. The EM-n flights are unlikely to be the only visits to the DSG.

Offline TaurusLittrow

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #50 on: 06/17/2017 12:20 PM »
Long-term reliable ECLSS is one issue for DSG but equally pressing are human factors esp. radiation exposure. I believe one or more Apollo missions missed significant (potentially fatal) solar particle events (SPE) during their short forays BEO. One large SPE occurred between Apollo 16 and 17.

The DSG will need some type of radiation "storm shelter" on-board for the crew. Given that DSG will include a propulsion module, is using the moon as a shield during an SPE by re-positioning the outpost an option?  Any public sources on this topic specifically for DSG?

Offline Oli

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #51 on: 06/17/2017 01:33 PM »
This is the whole problem with this DSG plan. If you want to test long term ECLSS then just focus on ECLSS, if you want to build DST then build it, drag DSG into it will only mean less funding for things actually matter.

The point of DSG is to give SLS/Orion something to do until DST is ready. Experience gained is a bonus.
Plus international partners want it as it get them closer to moon.

They have no money to land on the moon.

Offline TrevorMonty

No country except maybe China can afford to fund a lunar architecture with earth as your starting point. Apollo did it at huge cost and Constellation tried.

If the starting point is 2.5km/s from lunar surface and only thing required is lander capable of 5-5.5km/s then develop costs are lot lower. A lot easier sell especially if it could be operation within 5yrs of approval. I suspect there will be cargo landers operating by time DSG is in place, making development of human lander more affordable than it is now.
« Last Edit: 06/17/2017 04:34 PM by TrevorMonty »

Offline ncb1397

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #53 on: 06/18/2017 04:52 PM »
This is the whole problem with this DSG plan. If you want to test long term ECLSS then just focus on ECLSS, if you want to build DST then build it, drag DSG into it will only mean less funding for things actually matter.

The point of DSG is to give SLS/Orion something to do until DST is ready. Experience gained is a bonus.
Plus international partners want it as it get them closer to moon.

They have no money to land on the moon.

Applying the funding split ratio between the Apollo LM and the CSM to Orion and a new lunar lander, a lander would require funding of about $800 million per year.

Funding by agency
NASA: ~$19.6 billion
ISRO: ~$1.2 billion
ESA: ~$6.4 billion
CNSA: ~$1.3 billion
JAXA: ~$2 billion
Roscosmos: ~$3.2 billion
KARI: $583 million

In reality, any of a half dozen space agencies could afford it. Probably including south korea's if that was their only project.

Offline Zed_Noir

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #54 on: 06/18/2017 05:20 PM »
No country except maybe China can afford to fund a lunar architecture with earth as your starting point. Apollo did it at huge cost and Constellation tried.

If the starting point is 2.5km/s from lunar surface and only thing required is lander capable of 5-5.5km/s then develop costs are lot lower. A lot easier sell especially if it could be operation within 5yrs of approval. I suspect there will be cargo landers operating by time DSG is in place, making development of human lander more affordable than it is now.

Don't think even China can set up an Earth based architecture with their currently planned space vehicle development program. IMO

However the folks from Hawthorne can in theory set up a system of propellant depots at LEO, L4/L5 & HLO  locations with the ITS tankers as both depots and propellant transfer vehicle plus act as Lunar lander. Of course this system does not need the SLS, Orion, DSG and inspace SEP tug. So it will be a race for NASA to field a DSG before the ITS tanker enters servuce. Presuming the ITS development program is happening & somewhat on time.

Offline Coastal Ron

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #55 on: 06/18/2017 05:42 PM »
They have no money to land on the moon.

Applying the funding split ratio between the Apollo LM and the CSM to Orion and a new lunar lander, a lander would require funding of about $800 million per year.

$800M/year for how many years? What are you assuming the cost of a new lunar lander would be?

Plus, Oli did not state they couldn't afford a lander, but that there was no money to land on the Moon. Which to me means the funding for the entire effort, not just a transportation element.

Quote
Funding by agency
NASA: ~$19.6 billion
ISRO: ~$1.2 billion
ESA: ~$6.4 billion
CNSA: ~$1.3 billion
JAXA: ~$2 billion
Roscosmos: ~$3.2 billion
KARI: $583 million

In reality, any of a half dozen space agencies could afford it. Probably including south korea's if that was their only project.

You are assuming that each of those space agencies could easily substitute a $800M/year lander program for programs they are already committed to working on - which ignores the constituents of those other programs.

As to the U.S. all monies come from the general fund, and there is no constitutional limit on how much money Congress can allocate to NASA. If it's important Congress will fund it - we've already seen that Congress is OK for deficit spending.

Same with the DSG/DST. If Congress thinks it's important to have a national asset in cislunar space, then they will fund it. That won't happen in the FY2018 fiscal year though, so yet again payloads and missions for the SLS and Orion will not be committed to - not sure how much longer that can happen before it's recognized as a trend...
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline ncb1397

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #56 on: 06/18/2017 06:06 PM »
They have no money to land on the moon.

Applying the funding split ratio between the Apollo LM and the CSM to Orion and a new lunar lander, a lander would require funding of about $800 million per year.

$800M/year for how many years? What are you assuming the cost of a new lunar lander would be?

Plus, Oli did not state they couldn't afford a lander, but that there was no money to land on the Moon. Which to me means the funding for the entire effort, not just a transportation element.

Quote
Funding by agency
NASA: ~$19.6 billion
ISRO: ~$1.2 billion
ESA: ~$6.4 billion
CNSA: ~$1.3 billion
JAXA: ~$2 billion
Roscosmos: ~$3.2 billion
KARI: $583 million

In reality, any of a half dozen space agencies could afford it. Probably including south korea's if that was their only project.

You are assuming that each of those space agencies could easily substitute a $800M/year lander program for programs they are already committed to working on - which ignores the constituents of those other programs.

As to the U.S. all monies come from the general fund, and there is no constitutional limit on how much money Congress can allocate to NASA. If it's important Congress will fund it - we've already seen that Congress is OK for deficit spending.

Same with the DSG/DST. If Congress thinks it's important to have a national asset in cislunar space, then they will fund it. That won't happen in the FY2018 fiscal year though, so yet again payloads and missions for the SLS and Orion will not be committed to - not sure how much longer that can happen before it's recognized as a trend...

Ohh, I think DSG is already in the process of being acquired. For instance, engines:

Quote
Aerojet Rocketdyne, a subsidiary of Aerojet Rocketdyne Holdings, Inc. (NYSE:AJRD), has signed a $67 million cost-plus fixed fee (plus performance incentive) contract with NASA to develop a high-power electric propulsion system that will enable key elements of NASA's plans for exploration of cis-lunar space and Mars.

Under the Advanced Electric Propulsion System (AEPS) contract, the Aerojet Rocketdyne team will develop, qualify and deliver five 12.5 kilowatt Hall thruster subsystems including thrusters,
http://www.rocket.com/article/aerojet-rocketdyne-signs-contract-develop-advanced-electric-propulsion-system-nasa

ARM is in the process of being shut-down and these will be transferred to DSG to act as 4 flight units and one spare.

Offline punder

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #57 on: 06/18/2017 06:25 PM »
Luke, it's a trap!

DSG will neatly close the USG/contractor "business case." Deep space destination for US HSF: Check. Big flashy rocket and spacecraft for transportation thereto: Check. Throw in some low-mass science experiments on each flight, and... what more could you want? Or more precisely, what more could you get? Because for the next 20 years, your entire budget will be barely adequate for maintaining the DSG and building/launching/disposing of its transportation system.

And that will be that.

Offline AncientU

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #58 on: 06/20/2017 01:53 PM »
Luke, it's a trap!

DSG will neatly close the USG/contractor "business case." Deep space destination for US HSF: Check. Big flashy rocket and spacecraft for transportation thereto: Check. Throw in some low-mass science experiments on each flight, and... what more could you want? Or more precisely, what more could you get? Because for the next 20 years, your entire budget will be barely adequate for maintaining the DSG and building/launching/disposing of its transportation system.

And that will be that.

Ars Technica article agrees:
Quote
The Journey to Mars seems to be pretty much dead

Quote
On Friday, the space agency released what it called a "mid-year report" on NASA five months into the presidency of Donald Trump. The nearly five-minute video...

Quote
...the video makes no mention of Mars at all, the planet where NASA has by far the most assets of any world other than Earth—several rovers and orbiters studying the red planet's surface and atmosphere for clues of its past habitability for life. NASA has made a number of significant discoveries about Mars this year, such as confirming the absence of carbonate in rocks there. But none merit mention in the promotional video.
Journey to Mars

The red planet is also excluded from the video's discussion when it comes to human exploration. Prior to this year, the agency's off-stated goal was sending humans to Mars in the 2030s. This "Journey to Mars" had been a frequent talking point for then-administrator Charles Bolden and other agency leaders. They talked about the Space Launch System rocket and Orion spacecraft as key components of this mission.

https://arstechnica.com/science/2017/06/the-journey-to-mars-seems-to-be-pretty-much-dead/
« Last Edit: 06/20/2017 01:53 PM by AncientU »
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Offline MATTBLAK

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Re: ASAP on board with NASA's DSG as stepping stone to Mars
« Reply #59 on: 06/21/2017 01:17 PM »
SLS/Orion always seemed much more a 'Moon Rocket' and spaceship to me. A lunar gateway station, with or without any Mars endgame in sight could be a good place to base and service/refuel a reusable lunar lander craft. If the Lander is a Commercially-competed craft or a joint venture between NASA and it's partners... Seems to me a better way of doing things than the purely Constellation modus-operandi.

As I've liked to say before: America could provide the Orion 'Mothership' and the heavy lifter (SLS and/or others) and a NASA/Commercial co-op or ESA/JAXA partnership could provide the reusable Lunar Lander (2,3 or 4 Astronauts). Have the Lander be either a crew or cargo version - a bit like Soyuz/Progress as the two 'flavors' it now comes in. Commercial space entities could compete for cargo deliveries to the Gateway station, as they did to ISS. Also - the Orion could bring a 'Tanker Module' of propellants for the Lander with each crew it brings to the Gateway Station. With Block SLS 1B; Orion could bring 10 tons of propellants for a Lander. With the Block 2 - about 20 tons.

The crew and cargo missions to the Moon could rely on a best-case scenario of the SLS flight rate; which would be 3 or 4 flights per year. With 3x flights - two could be crewed and one could be cargo only. This could allow one 'Sortie' manned mission and one longer duration mission, using the equipment and consumables of the cargo lander. Allowing for an Outpost buildup, the missions could be increased to 2x longer duration Outpost flights per year after a 'simple' Outpost has been established. It would make sense to have the Outpost be a NASA/ESA/JAXA partnership; joined by Commercial Space entities. After a few years of Outpost and Gateway station missions - I consider the Gateway to be the natural successor to ISS - considerable experience in deep space manned mission exploration operations would be accumulated. And the reach for Mars would be happening all in good time; with or without the cooperation of Commercial Space, such as the Musk dream of Mars colonization. Of course - the Gateway does not need to be a 450 ton behemoth at DRO or a Lagrange Point. Something closer to Mir or the projected Chinese station should suffice.

In time, the SLS/Orion system could be supplanted and then superseded by more modern, efficient and more fully reusable space transportation systems. I still believe commercial space entities such as SpaceX and Blue Origin are going to one day hit their stride in a spectacular fashion. Call it faith-based, if you like. And I'm fully aware that everything I just wrote above is best-case scenario in nature. If it happens at all; it will be a slow variation on what I've written. :) :(
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