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#201 2021-09-13 08:46:35

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,745
Website

Re: Deep Space Gateway; a bad joke by NASA?

There are two very serious problems with the Gateway station in this odd halo orbit.  One is quite literally fatal to its crew. 

The delta-vee to reach it from Earth is actually a bit lower than the delta-vee to reach a low lunar orbit similar to Apollo,  especially one oriented polar.  That puts Gateway within reach of SLS Block 1 with the (overweight) Orion and (underpowered) service module it has.  SLS-block1/Orion cannot successfully reach the low lunar orbit used by Apollo,  much less a polar-oriented low lunar orbit.

From low lunar orbit,  the theoretical delta-vee required to land is comparable to the low orbit velocity:  about 1.6-something km/s.  Actual is a tad higher due to gravity losses and propellant safety margins.  This is true whether the orbit is equatorial or polar. 

From the halo orbit,  you have a trivial burn of a few m/s at apolune to put you onto a surface-grazing transfer ellipse, BUT,  the perilune velocity is what you have to "kill" to land!  From that orbit,  the perilune velocity is trivially-less than lunar escape velocity:  2.5-something km/s.  That's 41% higher than from low lunar orbit!

That's NOT the fatal problem,  it is just added difficulties designing lunar landers with a lot more mass ratio than they should otherwise need,  all because SLSblock-1/Orion is a faulty moon rocket design,  with enormous sunk costs that NASA is unwilling to write off.  They couldn't write it off,  even if they wanted to,  because Congress,  not NASA,  controls ALL of NASA's money.  Congress has micromanaged NASA for decades,  and they are NOT competent to do so!  They never have been.  It is really starting to show,  too!

The fatal problem is sudden solar flare events of large magnitude.  Not all are lethally large,  but some are.  The Gateway station design does NOT have a radiation shelter for its crew,  but in that (or any) orbit about (or even near) the moon,  it has no effective shielding from Earth's magnetosphere. 

The Apollo data show that typically spacecraft hulls can cut that kind of radiation roughly in half,  but that's not good enough for a big event,  not by a very long shot!  You might be looking at as much as 5-to-10 THOUSAND REM accumulated over 5-10 hours.

This is not galactic cosmic rays I am talking about;  that's a thin drizzle of far higher-energy particles,  difficult to shield.  But there's actually very little of it:  some 24 to 60 REM accumulated over a year.  Supposedly,  accumulating 400 REM over a career in space increases your risk of late-in-life cancer by something like 3%.

300 REM accumulated in a "short time" (hours to days) is lethal to 50% of those exposed,  the other 50% very-nearly dying of severe radiation sickness.  Extremely severe.  500 REM is lethal to 100% of those so exposed.  It is a very,  very ugly death.

There was indeed an event of that magnitude,  between the last two Apollo missions to the moon in 1972.

As it says in the quote beneath my byline,  there is nothing as expensive as a dead crew,  especially one dead because of a bad management decision.  This is a TERRIBLY BAD management decision!  It WILL kill a crew!

GW

Last edited by GW Johnson (2021-09-13 08:56:23)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#202 2021-09-13 09:44:34

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,271

Re: Deep Space Gateway; a bad joke by NASA?

GW-

Here is a repost of my original opener for this thread:

"Ever since NASA announced their latest workfare program for their favored contractors, I've been wondering exactly who came up with this terrible idea. It sounds like a bad medical experiment designed by Josef Mengele for the residents of a concentration camp!

The idea of placing a long-term habitat in cis-lunar space with no provision for shielding from solar flare radiation and GCR, and which makes  no attempts made to alleviate the effects of microgravity, makes me wonder just what they hope to achieve other than killing or seriously injuring the astronauts involved. First proposed by NASA, and now we have the ESA jumping on board the idea along with the Russians. Other than providing something to justify the enormous amount of capital expended on the SLS, it seems to serve no truly useful purpose. It's another NASA let's all get on board and go...nowhere."

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#203 2021-09-13 17:39:07

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 24,442

Re: Deep Space Gateway; a bad joke by NASA?

you could blame that on the prime contractors that used an ISS for a model....

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#204 2021-12-03 11:01:43

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 1,267

Re: Deep Space Gateway; a bad joke by NASA?

I think the design for the Japan car looks great, the Japanese 'Lunar Cruiser'

The strange Lunar orbit habitat seems to have bureaucracy coming along with it

However there will also be stations in LEO


Building A Space Station In A Weird Orbit. Here’s Why
https://hackaday.com/2019/02/25/nasa-is … heres-why/
NASA reveals the 3 contenders to replace the International Space Station
https://www.slashgear.com/nasa-reveals- … -03701144/

A Mars space station is an interesting idea but this with the CGI and presenations this Moon kind of one is sometimes like a poorly done epsiode of Deep Space 9? I hope they know what they are doing!

SpaceNut wrote:

Looks like we are going to need a different partner for getting to the moon.

Might be good news since the USA never needed Russia to get to the Moon.

more space politics

'Russia Legally Threatens NASA Astronaut for Allegedly Sabotaging Space Station'
https://futurism.com/the-byte/russia-th … t-sabotage
NASA and Russia negotiating to dock vehicles in the Russian ‘node’
https://techstory.in/nasa-and-russia-ne … sian-node/

Last edited by Mars_B4_Moon (2021-12-03 11:09:00)

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#205 2021-12-03 19:04:17

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 24,442

Re: Deep Space Gateway; a bad joke by NASA?

While I think a station for the moon is a poor idea its not going to get all that much use from starships unless its layout changes dramatically so as to get it dock able to the docking ports.

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#206 2022-01-01 20:54:03

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 24,442

Re: Deep Space Gateway; a bad joke by NASA?

Mars_B4_Moon wrote:

What can the Moon or the ISS or Gateway truly tell of a Manned Mars Station or Mars Biodome or Manned Mars Excursion Module, some argue that more must be tested on the station and on the Moon. It seems the Moon will be an international efforst to make a Moon base and the revised Japanese plan includes landing a Japanese astronaut on the Moon in the latter half of the 2020s. Others wonder about the cost justification of lunar Gateway, what if for example the Chinese were to put major effort in Mars while NASA remained focused on trying to turn the Moon into some kind of base or launch pad or manufacturing plant? Mars could one day have exports and perhaps could be used as a base to ship other low tech products to other colony sites across the solar system for example the asteroids but shipping  "commodity stuff" from Mars to Earth does not make any sense economically.

NASA's "sustained" lunar presence.
https://twitter.com/wingod/status/1474254134320582657

ISS Operations Extended To 2030
http://spaceref.com/international-space … -2030.html

NASA updates Artemis I integrated testing schedule
https://www.aerotechnews.com/blog/2021/ … -schedule/

The wiki entry on the Gateway

NASA officials promote the Gateway as a "reusable command module" that could direct activities on the lunar surface. However, the Gateway has received both positive and negative reactions from space professionals.

Formerly known as the Deep Space Gateway (DSG), the station was renamed Lunar Orbital Platform-Gateway (LOP-G) in NASA's 2018 proposal for the 2019 United States federal budget. When the budgeting process was complete, US$332 million had been committed by Congress to preliminary studies.
https://en.wikipedia.org/wiki/Lunar_Gateway
Gateway will be the first modular space station to be both human-rated, and autonomously operating most of the time in its early years, as well as being the first deep-space station, far from low Earth orbit. This will be enabled by more sophisticated executive control software than on any prior space station, which will monitor and control all systems. The high-level architecture is provided by the Robotics and Intelligence for Human Spaceflight lab at NASA, and implemented at NASA facilities. The Gateway could conceivably also support in-situ resource utilization (ISRU) development and testing from lunar and asteroid sources, and would offer the opportunity for gradual buildup of capabilities for more complex missions over time.

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#207 2022-01-01 20:55:11

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 24,442

Re: Deep Space Gateway; a bad joke by NASA?

As the title indicates its a bad idea one from the stand point of radiation protection circling the moon and acting as a way station.

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#208 2022-01-02 11:46:34

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,271

Re: Deep Space Gateway; a bad joke by NASA?

The main purpose of the Gateway is generation of jobs for "Old Space."

The radiation protection from Solar Flare emissions in the designs I've seen is totally non-existent. No provision for any artificial gravity--which is absent all NASA designs. No provision for any Cosmic Ray shielding, either, which is the least of the worries for the inhabitants.

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#209 2022-01-02 11:56:41

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,745
Website

Re: Deep Space Gateway; a bad joke by NASA?

I concur fully with OF's assessment in post 208.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#210 2022-01-02 12:12:50

tahanson43206
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Registered: 2018-04-27
Posts: 8,675

Re: Deep Space Gateway; a bad joke by NASA?

The Deep Space Gateway may be morphing into an equipment site, instead of a location for habitation.  There would seem to (me at least) to be some value in having a fully featured Lunar Orbiter with sufficient heft to maintain itself in orbit.

Such a facility could serve as a temporary emergency-only shelter for a spacecraft carrying passengers, and it could even serve as an orbiting supply point, again for emergencies.

That would be a useful role, and potentially worth all the billions that have been invested in the save-old-space jobs over many years now.

(th)

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#211 2022-01-02 15:46:22

Oldfart1939
Member
Registered: 2016-11-26
Posts: 2,271

Re: Deep Space Gateway; a bad joke by NASA?

I'm still in absolute agreement with Robert Zubrin, who referred to it as a "Lunar Tollbooth."

"Ya ain't goin' to the Moon, unless ya pay Old Space a hefty toll."

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#212 2022-01-03 16:42:29

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,745
Website

Re: Deep Space Gateway; a bad joke by NASA?

I have noticed recently that the highly-elongated orbit of Gateway is about one of the Lagrange points,  not the moon itself.  My analysis presumed a 3000 km x 14,000 km ellipse about the moon,  so I was wrong.  That weird orbit makes it easiest for SLS to reach,  with usable payload.  But the one-way trip to or from the moon now exceeds lunar escape delta-vee,  plus a lunar gravity loss. 

That choice made the lander design problem worse from a mass ratio standpoint,  but it makes landing anywhere on the moon easier than from low lunar orbit with an expensive plane change.  Just like in my analysis,  even from the Lagrange point,  while way out there at low speed,  that's when you do the least-cost plane change. Plane change delta-vee is directly proportional to the sine of the angle change,  and to the speed at which you are moving.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#213 2022-01-03 20:42:49

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 24,442

Re: Deep Space Gateway; a bad joke by NASA?

It became a 2 rocket launch for the moon when the gateway came about but then again that is what was slated even back when we had Ares 1 for Orion on the roman candle srb launch system. Its also why we need the block 2 rocket with the higher payload capability.

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