Coherent Mars plan

GCNRevenger · 2005-08-22 13:40:03

Don't want to go to Mars? Of course I want to go to Mars, but I unlike Zubrin and his "ends justify" acolytes think that a mad, blind rush to get there would be a real tragedy. There are things worth doing on the Moon, and if we are going to the Moon anyway, then its stupid to sacrifice these bennefits given the modest marginal cost. This means going to the Moon with vehicles that are bigger, more capable, and designed specifically for the Moon. The same deal with Mars, we could get there a little faster and cheaper with vehicles too small to get much done, but that would be a waste of time and money... Sure we'd get our boots red, maybe get some pretty pictures and pretend to hunt for bugs, but what would be accomplished? Some Moon/Mars hardware commonality is possible, like small engines, nuclear reactors, life support gear, maybe even use a Mars hab for a prefab base, but imposing too much commonality will nessesarrily hurt the efficiency or effectiveness of a Lunar program... They could both use the same inline SDV launch vehicle, with different upper stages probobly, thus saving alot of headache there.

Shuttle-C won't be able to help construct the ISS because it cannot be built before Shuttle will be retired. If we started right now today, it would take about three years at a minimum before it would be ready to fly. By that time, it is unlikly that Shuttle will be flying much longer, and it will be sharing infrastructure with Shuttle. If Shuttle-C can carry double the payload of Shuttle (by volume), that doesn't leave you much opportunity - just a few months - to fly it. Without Shuttle, Shuttle-C would have to either be towed by a tug, or have tug hardware built in, either of which will add to its multi-billion-dollar cost. Shuttle-C will probobly cost around $4-5Bn to develop, adding in another billion for tug hardware, and you are only talking about saving a year or two worth of Shuttle money. I am not impressed.

Asset? The ISS isn't an asset, its a noose around NASA's neck! There is an obvious counter-point to the notion that Congress would not forgive NASA for canceling future ISS work, which is that the ISS will have very little worth for the money NASA seeks to spend on it (~$50Bn) between now and the 2017 "cutoff" date. Is it a sign of maturity to soldier on with a program that has so little bennefit? Or is it a sign of maturity to admit that the ISS project is impractical and useless, and no more of NASA's quite limited taxpayer dollars would be wasted on it. On the contrary, it is for the sake of Mars that NASA be honest and do the painful things, starting with admitting that pre-VSE style blundering on obliviously is not acceptable, and a true course change is needed.

John Creighton · 2005-08-22 13:44:38

I'm a bit confused here weren’t you the one advocating using the same hardware for the moon and mars.
Shuttle-C can be used for the 2-launch per transit to Mars mission plan of NASA's DRM. It isn't preferred but also remember I called for a line of SDVs. One thing the space industry is finally beginning to realize is you can't just build one single rocket without any flexibility to payload and expect everyone will adapt their mission to your vehicle. A reasonable launch vehicle must be configurable to mission requirements. The Russian Proton has various upper stages available, Energia was designed to work with varying numbers of strap-on boosters, and the Angara has options to mix-and-match modules. Delta IV and Atlas V also have varying configurations. The new SDV must do the same. Shuttle-C is the smallest configuration of the family, but the easiest and quickest to get operational. The larger SDV you want is simply another member of that family. We need something that can be operational quickly and inexpensively to finish ISS. The small one optimized for LEO is ideal for ISS.

I’d be interested in that approach if it can be shown to be affordable and practical. I am not sure if there is enough overlap between the two vehicles for this to be practical. I don’t know if the same launch facilities can be used to launch both the shuttle c and inline SDV. I don’t know if the tooling at McLeod can be used to produce both tanks or if the cost and delays between switching tooling for each type of tank will be considerable. I don’t know what extra facilitates are required to support the shuttle c that aren’t required to support the SDV. For instance the shuttle c will use a unique engine pod to the CEV. Clearly there won’t be much in common between the shuttle c engine pod and the CEV for the inline SDV. Thus separate facilities will be needed to build and maintain each of these components. Also the engineering work between those two components won’t overlap. The inline SDV promises to reduce the operating cost more then shuttle C.

If you want a bigger medium lift vehicle perhaps an upgraded EELV is a better option.

GCNRevenger · 2005-08-22 14:09:36

I'm a bit confused here weren’t you the one advocating using the same hardware for the moon and mars.
Shuttle-C can be used for the 2-launch per transit to Mars mission plan of NASA's DRM. It isn't preferred but also remember I called for a line of SDVs. One thing the space industry is finally beginning to realize is you can't just build one single rocket without any flexibility to payload and expect everyone will adapt their mission to your vehicle. A reasonable launch vehicle must be configurable to mission requirements. The Russian Proton has various upper stages available, Energia was designed to work with varying numbers of strap-on boosters, and the Angara has options to mix-and-match modules. Delta IV and Atlas V also have varying configurations. The new SDV must do the same. Shuttle-C is the smallest configuration of the family, but the easiest and quickest to get operational. The larger SDV you want is simply another member of that family. We need something that can be operational quickly and inexpensively to finish ISS. The small one optimized for LEO is ideal for ISS.
I’d be interested in that approach if it can be shown to be affordable and practical. I am not sure if there is enough overlap between the two vehicles for this to be practical. I don’t know if the same launch facilities can be used to launch both the shuttle c and inline SDV. I don’t know if the tooling at McLeod can be used to produce both tanks or if the cost and delays between switching tooling for each type of tank will be considerable. I don’t know what extra facilitates are required to support the shuttle c that aren’t required to support the SDV. For instance the shuttle c will use a unique engine pod to the CEV. Clearly there won’t be much in common between the shuttle c engine pod and the CEV for the inline SDV. Thus separate facilities will be needed to build and maintain each of these components. Also the engineering work between those two components won’t overlap. The inline SDV promises to reduce the operating cost more then shuttle C.
If you want a bigger medium lift vehicle perhaps and upgraded EELV is a better option.

Shuttle-C as proposed cannot be used for NASA-DRM, because it lacks the payload volume nessesarry (6.5m max dia) to carry either the HAB/ERV/MAV or the nuclear TMI stage.

It is also too small for an efficent Lunar program, since the ideal arrangment is one heavy SDV with the lander and TLI stage, which would be just big enough to bring useful payload and larger (up to six) crews. A smaller launcher like Shuttle-C cannot do this, and is hence disqualified from the Lunar program.

There will be no commonality between a heavier in-line SDV and Shuttle-C beyond the main engines and some of the avionics boxes. Different tank, different orbital circulization strategy, different launch table, different flame trenches, different tower umbilicals and VAB catwalks, it has an upper stage, it would need a low-ambient-pressure upper stage engine, and so on.

A question begs, if inline launchers like Magnum or Longfellow are good for Moon/Mars, then why do we need Shuttle-C for? All the money and time spent on it will be essentially wasted, and if the only thing it can do that is really worthwhile is build/tend the ISS, that really isn't a very good reason to build it. We don't need a "flexibility," we need one large rocket, with as little difference between Moon and Mars models as possible (like different upper stages only).

Since most of the major componets are already available however, I don't think that an inline launcher would take a full eight years to develop. Saturn was a brand new rocket, and nothing like it had exsisted before. This is not the case with SDV, which will probobly cut a few years off that figure.

I would also like to add, if maturity is finishing the worthless space station or propping up the decrepit Hubble a little longer, then what do you call giving up doing much useful work, after spending tens of billions of dollars, on the Moon before you even set out to return? That is exactly what the "build Mars analouge base and rotate crews only" route gets you.

RobertDyck · 2005-08-22 20:21:59

The avionics box is common with the big inline SDV (is that what you call Longfellow?), the fairing exists and is common with Delta IV & Atlas V, the MLP and launch pad are common with Shuttle orbiter, engine section from the Shuttle orbiter, the parafoil is off-the-shelf. Recovery equipment is the existing vehicle to drain Shuttle's MMH & N2O4 tanks, and a single stock fletbed truck with truck crane to drive the engine pod back to the cape. A parafoil is preferred to make the lifter useful for heavy lift to LEO, including space hotels and any Earth orbit assembly architecture. Marshall has done a lot of work on Shuttle-C already, how much more to get it flying? I'm serious when I said flight this winter.

SpaceNut · 2005-08-23 05:16:49

As for using shuttle C to complete the ISS if it can be shown to be cheaper and faster then using the shuttle then I would support it. I believe NASA is studying this possibility. However, I am not going to relay on the unreviewed work of on person unless you can show me great errors in the way NASA does it's planning and costing of such operations.

This study was done a long time ago but since then the amount of refurbishment has most likely gone up on the orbiter, so IMO it should be better than a break even doing shuttle -c for cost per launch.

Shuttle-C won't be able to help construct the ISS because it cannot be built before Shuttle will be retired. If we started right now today, it would take about three years at a minimum before it would be ready to fly.
Shuttle-C will probobly cost around $4-5Bn to develop, adding in another billion for tug hardware, and you are only talking about saving a year or two worth of Shuttle money.

However where does the developement money come from? Why would it take so much engineering time to create the cargo attachment? Also why so much for developement?

The avionics box is common with the big inline SDV (is that what you call Longfellow?), the fairing exists and is common with Delta IV & Atlas V, the MLP and launch pad are common with Shuttle orbiter, engine section from the Shuttle orbiter, the parafoil is off-the-shelf. Recovery equipment is the existing vehicle to drain Shuttle's MMH & N2O4 tanks, and a single stock fletbed truck with truck crane to drive the engine pod back to the cape. A parafoil is preferred to make the lifter useful for heavy lift to LEO, including space hotels and any Earth orbit assembly architecture. Marshall has done a lot of work on Shuttle-C already, how much more to get it flying? I'm serious when I said flight this winter.

Great list of what is need and what we have for shuttle -c.
The avionics would be needed for any alteration of lockheeds atlas or boeings delta derivative as well. This is also a need for the sdv stick.

As mashall goes, I think that they should have already done the work for shuttle c beyound the mockup a long time ago.

srmeaney · 2005-08-23 05:49:32

One person per launch vehicle to Mars with x years food/supplies at the rate of 500 launches per day world wide Squeezed into the optimal window to handle that capacity of traffic to Mars (100,000 colonists per year).

Hab groups then cluster at landing sites on Mars.

Ten million colonists to Mars, cost: two hundred million billion dollars.

Every plan must cost less than this.

GCNRevenger · 2005-08-23 09:11:39

As for using shuttle C to complete the ISS if it can be shown to be cheaper and faster then using the shuttle then I would support it. I believe NASA is studying this possibility. However, I am not going to relay on the unreviewed work of on person unless you can show me great errors in the way NASA does it's planning and costing of such operations.
This study was done a long time ago but since then the amount of refurbishment has most likely gone up on the orbiter, so IMO it should be better than a break even doing shuttle -c for cost per launch.
Shuttle-C won't be able to help construct the ISS because it cannot be built before Shuttle will be retired. If we started right now today, it would take about three years at a minimum before it would be ready to fly.
Shuttle-C will probobly cost around $4-5Bn to develop, adding in another billion for tug hardware, and you are only talking about saving a year or two worth of Shuttle money.

However where does the developement money come from? Why would it take so much engineering time to create the cargo attachment? Also why so much for developement?
The avionics box is common with the big inline SDV (is that what you call Longfellow?), the fairing exists and is common with Delta IV & Atlas V, the MLP and launch pad are common with Shuttle orbiter, engine section from the Shuttle orbiter, the parafoil is off-the-shelf. Recovery equipment is the existing vehicle to drain Shuttle's MMH & N2O4 tanks, and a single stock fletbed truck with truck crane to drive the engine pod back to the cape. A parafoil is preferred to make the lifter useful for heavy lift to LEO, including space hotels and any Earth orbit assembly architecture. Marshall has done a lot of work on Shuttle-C already, how much more to get it flying? I'm serious when I said flight this winter.
Great list of what is need and what we have for shuttle -c.
The avionics would be needed for any alteration of lockheeds atlas or boeings delta derivative as well. This is also a need for the sdv stick.
As mashall goes, I think that they should have already done the work for shuttle c beyound the mockup a long time ago.

MSFC never did much real engineering work on the Shuttle-C concept beyond mold lines and performance figures. They had some idea of the parts they needed to build it, but that was about it... And they were talking development times of 18 months just for the throw-away wingless shuttle model. If it takes two solid years to build a Shuttle orbiter, with blueprints basically in hand, its going to take at least that long to develop the engine module and other modifications since signifigant development must be done, plus then you have a test flight or two. I also don't get why Magnum/Longfellow will take ninety-six months, but Shuttle-C - with the substantial modifications needed (new avionics, guidence systems, RCS mods, massive heat shield/shroud, payload cradle/faring) - is to be done in less than six months... This business from a certain board member about Shuttle-C being ready by years end is obviously completely outside the realm of possibility... Its not happening, and anybody who thinks it is must either be willfully ignorant or deceptive.

Magnum is the four e-SSME heavy core, and Longfellow is the four RS-68 core, which trades Isp for thrust and lower engine cost. Impressively enough, this tradeoff results in almost identical payload mass, but a ~50% reudction in engine costs.

RobertDyck · 2005-08-23 11:35:33

The tricks to reduce development time for Shuttle-C are using Shuttle orbiter's existing engine room and work already done at Marshall. Yes, I said replacing 3 APUs with 1, and reducing APU fuel to 15 minutes instead of 120, and replace the aluminum skin with graphite/epoxy like OMS pods. Those are small changes. An inline vehicle requires much more engineering. An inline vehicle also requires changes to the VAB and MLP. I don't know if it needs any change to the flame trench. Shuttle-C would need support struts instead of orbiter wing supports, but those struts could be just bolted in place.

As for APU, I remind you the orbiter needs hydraulic power for main engine gimbals (OMS gimbals are electric), as well as open/closing cargo bay doors, deploying landing gear, and operating air surfaces (flaps, elevons, rudder, airbrake). The only hydraulics Shuttle-C would have is main engine gimbal. Main engines fire for 8 minutes and the APU is started 5 minutes before launch; 15 minutes of APU fuel includes 2 minutes of contingency before hydraulics aren't needed any more.

I would use a Commercial Off The Shelf (COTS) space hardened Single Board Computer (SBC) for the flight computer. I know one that masses 1.5kg with a processor based on the IBM PowerPC with more CPU speed than all 5 Shuttle orbiter computers combined. The orbiter had 1970s vintage IBM computers, each as big as a bar fridge, 4 main computers plus 1 backup. This COTS SBC was designed for communications satellites, it's latch-up immune and rated for one radiation induced upset every 300 years; a launch vehicle is only up there for days at most. Triple modular redundant IBM PowerPC750FX processors, logic detects a processor upset, flushes cache, restores and resynchs processors in 1 microsecond. Power consumption software selectable from 5-20 watts: more power for more CPU speed. It runs VxWorks (same as Mars Pathfinder, Sprit & Opportunity), and operating temperature -40...+70°C. It's as big as a PC motherboard. There's your flight computer, off the shelf.

Flight software: Shuttle-C would port Shuttle orbiter software to the new hardware. A configuration that replaces the orbiter with payload fairing uses the same thrusters, center of gravity (weight balance), and most importantly the same flight control actuators. That means the same control software. Changing the engine room requires changing software to use it. Flight software for a new vehicle would take ~2 years, porting flight software from the existing orbiter to Shuttle-C should take ~6 months. That's one reason I don't want to see significant changes in engines or gimbal actuators, as a programmer I have a good idea how much work is involved to change the software.

SpaceNut · 2005-08-23 12:06:33

So between the PC and the gimbal system is the only electronic hardware to design or to cludge from the existing.

RobS · 2005-08-25 00:32:36

Regarding the completion of ISS, the latest issue of *Ad Astra,* the magazine of the National Space Society, has an article by James Oberg titled "The Domino Effect: How Serious is the Shuttle Delay and What Harm Can it Cause?" The article talks about the cascading delays in completing ISS if the shuttle doesn't fly soon (and it won't). The article at the end (p. 17) mentions the Russian plan to build "Parom":

"The Russians are developing a space-to-space tug called "Parom," assembled from off-the-shelf spacecraft components that will be able to dock to station-bound payloads in parking orbits and haul them up to the station, but for a fee. It may be a bargain.

"Parom is a Soyuz-sized "flying tunnel" with docking mechanisms and rendezvous sensors at each end. Based at the space station, it would await the launching of large components or cargo canisters into low, parking orbits. Parom would also arrange to dock with Progress tankers, or with propellant supplies launched inside some of the cargo modules, to top off its own tanks as needed. It could handle, according to its designers, cargoes ranging in size from a few tons all the way up to shuttle-sized cargo unit of 30 tons."

Sounds like a solution to some of the modules that may not be able to ride to space on the shuttle, or future expansion modules to the station by other countries (like Japan).

-- RobS

RobertDyck · 2005-08-25 12:07:37

I found an online article about Parom. It's in Russian but a web translator provides English. Translated page here.

::Edit:: publiusr said the link doesn't work. The original is here from SpaceNews.ru in Russian. I translated it with http://www.translate.ru by clicking on the Brittish flag for English (it saves a cookie so you don't have to select English the next time you use the site), then click "Translate WWW" to translate a web page, then paste the URL and select Russian->English.

publiusr · 2005-08-25 12:58:13

You really don't want to go to Mars, do you? We have a wonderful opportunity with George W.'s VSE to get out of LEO and start exploring space again, but the trap is to get stuck on the Moon. If lunar equipment is not designed from the beginning to be Mars equipment then Mars just won't happen.
Edit: Don't forget, that just about every penny spent, every pad modification, and engineer man-hour on Shuttle-C is spent on a booster that is too small for Mars and too small for efficent Lunar expeditions. I think it is safe to say that building the Shuttle-C is a step backwards away from the Moon or Mars.
Money spent to build a simple heavy launcher will be more than regained by preventing 3 years of shuttle operation and stopping the construction phase of ISS.
I started this thread to call for unity and a cohesive plan. Hacking and slashing existing assets will not get you to Mars. Destroying multi-billion dollar space projects would simply tell congress that NASA is too irresponsible to be permitted another multi-billion dollar project. You are arguing against Mars. The first thing you have to prove to congress is that you can be responsible with the assets already paid for. If you're not responsible, you get nothing! If Shuttle wasn't so old I wouldn't call for it's demise either, but it is time. ISS isn't even complete yet, hasn't even started operation. I'm having trouble staying calm; you just don't get it. The alternative to rapidly completing ISS to to drag it out for the full duration. If Atlantis launches in September and if they get another launch in 2005, and if they can maintain 6 launches per year it will be spring 2009 by the time it's finished. Delays are bound to happen which is why 2010 is the earliest retirement of Shuttle. The current budget shows costs for Shuttle jumped up from about $5 billion per year to $7.5 billion for return to flight, but after it's budgetted to remain at $7.5 billion. Chris Shank said they cut several programs to pay for RTF. With on-going shuttle operation increased to that level they won't have anything left for an inline heavy launcher. That means the heavy launcher won't start development until 2010. Initial design work for Saturn V started in 1959, and the F1 engine in 1958, Apollo 4 launched an unmanned test of the Saturn V in 1967. An SDV should take less time but a major redesign like the inline vehicle will take time. That really will mean the first manned mission to the Moon in 2018. I expect all hardware will be dedicated to the Moon, not at all usable on Mars. That means another major project and starting over again for Mars. After spending all that money on the Moon, politicians will take a hiatus before proceeding on to Mars. Even the inline SDV heavy launcher used for the Moon will be old and decommissioned by the time they get around to Mars. That means starting everything over again. How many decades? Will there be a manned mission to Mars within our lifetime?

I agree with most of what you say--but the robotics missions also have to go. HLLV needs all the friends it can get. Let its enemies enjoy Rutans fantasies and Ayn Rand nonsense.

publiusr · 2005-08-25 12:59:58

I found an online article about Parom. It's in Russian but a web translator provides English. Translated page here.

I can't get that link to work.

RobertDyck · 2005-08-25 14:22:09

RobS linked an article to Flight International that states Chris Shank reported to them NASA will proceed with the inline launcher. This isn't optimal for LEO because it's expendable (read expensive) and separates main engines from cargo so there's no RCS thrusters to stabilize cargo. Adding stabilization thrusters to the payload would cost money and delay launch, it's unlikely to happen at all. As GCNRevenger pointed out, if there's no stabilization of the payload while on orbit then how does a reusable tug latch on? Even if NASA were willing to use the Russian Parom instead of developing its own tug, I don't see how it could connect. Small stabilization thrusters could be added with a fuel canister for Parom, but that adds more complexity. I see NASA rejecting that plan as too complicated, which means the inline launch vehicle can't be used to complete ISS.

Again, Shuttle-C is optimal for orbital assembly in LEO. The inline configuration is optimal for direct launch to the Moon or Mars. I think we need both. Shuttle-C can be completed quickly if we stop pissing around and just do it.

By the way, the article quoted Chris Shank as saying Shuttle-C lifts 70 tonnes; again that's only true of the 2 SSME version, the 3 engine version would lift 87 tonnes. The 100 tonne lift capacity quoted for the inline version is due largely to 4 engines and a stretched main tank.

If we build Shuttle-C with the first test launch in 6 months, first payload one month after that, we can complete all exterior construction of ISS by fiscal year end October 2006. If all 5 remaining missions of Shuttle with MPLM are done with ATV, and Japan is told their on their own with HTV, and no 5th Hubble space telescope mission in 2007, then the entire Shuttle program can be cancelled. JSC will have to remain for manned spaceflight and KSC facilities to support the SDVs, but it should reduce Shuttle's budget from $7.5 billion to $2 billion per year. Direct all $5.5 billion in 2007 to the inline SDV, or a portion to CEV. I think that will complete the inline SDV earlier.

Actually I doubt the orbiter would be cancelled quite that early, if HSM4 does not include a propulsion module as Chris Shank said then there'll have to be one more Hubble mission if only to de-orbit it. I doubt Europe is willing to undertake ~10 more ATV missions to replace the 5 Shuttle/MPLM missions. But ATV could take over some, and this means Shuttle's last year would be 2007 instead of 2010.

srmeaney · 2005-08-26 07:29:30

Personaly, I think the lunar vehicle propsed looks like a spacehab double logistics module on a lander base.

RobertDyck · 2005-08-26 11:52:28

According to Encyclopedia Astronautica, Ariane 5G costs $180 million in year 2000 dollars. The MPLM actually carries 9 tonnes of cargo in 16 International Standard Payload Racks. Encyclopedia Astronautica says ATV carries 7 tonnes in 8 racks including 860kg of propellant, 840kg of water and 100kg of atmospheric gases to 407km orbit at 51.6° inclination; but ESA's web site says it carries 7.5 tonnes to 400km orbit. Is that counting on rendezvous when ISS is lower? Its orbit does vary a bit; it has to be reboosted periodically. Let's use the 7.5 tonne figure but assume a Shuttle mission doesn't carry ISS fuel, reboosts with its OMS engines, and carries water and air in the Shuttle mid deck. That leaves 5.7 tonnes of ATV cargo vs Shuttle's 9. That means 5 MPLM missions will carry 5x9=45 tonnes, which could be carried by 45/5.7=7.8947 missions. There isn't such a thing as part of a launch, so 8 missions. Encyclopedia Astronautica's ATV web page says the cost is targeted at $70 million per ATV plus $115 million per Ariane 5. Hmm, when they pay for an Ariane 5 launch themselves it costs less than the price for a commercial customer; now we know their profit margin. At $185 million total for an ATV mission the 8 missions to replace Shuttle cargo would cost $1.480 billion. If cancelling the Shuttle orbiter a year early saves $5.5 billion then paying ESA $1.480 billion to take over launch of interior equipment would save $4.020 billion. Shuttle costs were rounded to 2 significant figures so make that $4.0 billion.

All this bean counting is convincing me to cancel Shuttle at NASA's fiscal year end, October 2006.

TwinBeam · 2005-08-26 13:36:26

Adding stabilization thrusters to the payload would cost money and delay launch, it's unlikely to happen at all. As GCNRevenger pointed out, if there's no stabilization of the payload while on orbit then how does a reusable tug latch on?

Why would adding RCS thrusters would be such a big deal, considering the substantial changes going to a linear stack will already require? Perhaps add them to the second stage, and don't discard that until the payload section is attached to the tug?

GCNRevenger · 2005-08-26 16:29:09

"cludge from the existing" shuttle design to build Shuttle-C

Ummmm. No. Its quite clear that whoever thinks that the Shuttle-C engine pod could be bodily copied from the orbiter in either a reasonably inexpensive or reuseable form doesn't know what they're talking about. Redesigning the power and control systems (not just the computers, the attitude gyros/GPS & software, remote controls), cutting the wings and crew cabin off, and so on would take a year or two to design. Any notion that Shuttle-C could be ready to fly in under 2-3 years for any reasonable sum is crazy... It is really very very simple, that Shuttle is a machine of such fantastic complexity - more then any one person can really comprihend, more then any other machine built by man,ever! - that retaining the design and making changes to it takes an "astronomical" amount of effort...

The proof of this is documented: a large part of the ~$5Bn a year that Shuttle absorbed was spent on developing relativly minor upgrades. No one, not even NASA, believed that Shuttle's complexity could be such a demon. They were wrong... and it is proposed to do something far more radical to the design? Apparently, some foolish optimists on this board have not learned from the mistakes of history. Even something that sounds so simple as cutting the wings, crew cabin, and heat shield off is, well, simply not. Any notions to the contrary are just plain obtuse and naieve.

"Why would adding RCS thrusters would be such a big deal"

It actually is kind of a big deal. Its not just the thrusters...
-Power supply req'd, solar cells & batteries or fuel cells and their associated tanks/plumbing/etc
-Gyroscopes or GPS sensor networks
-Control computers
-Bidirectional radio link to mission control with telemetry
-Guidence beacon for tugs
-Cameras too probobly

And to add tug functionality:
-Liquid restartable medium maneuvering rocket with signifigant fuel stores
-More robust and powerful RCS thruster systems with more fuel
-Radar or Lidar sensor systems
-Redundant cameras
-Image or radar/lidar image processing, with sufficent intelligence to excute rendezvous, perhaps even docking, automatically
-Image or radar/lidar image processing, with sufficent intelligence to execute an emergency abort maneuver automatically
-Higher bandwidth datalink to mission control, and likly to the rendezvous/docking target too

You'd be axing several tonnes of payload and jacking up the price some few tens of millions each for anti-spin RCS systems, and double or tripple that for tug functionality.

srmeaney · 2005-08-26 17:12:41

The proof of this is documented: a large part of the ~$5Bn a year that Shuttle absorbed was spent on developing relativly minor upgrades. No one, not even NASA, believed that Shuttle's complexity could be such a demon. They were wrong... and it is proposed to do something far more radical to the design? Apparently, some foolish optimists on this board have not learned from the mistakes of history. Even something that sounds so simple as cutting the wings, crew cabin, and heat shield off is, well, simply not. Any notions to the contrary are just plain obtuse and naieve.

The shuttle has one single characteristic that justifies keeping the ability to build it around. The Payload bay can deploy an unfolding frame which can dock with a second unmanned vehicle specificly designed to provide space propulsion (in whatever level of technology you want) A Logistics/mission module provides the capacity for the control and data analysis systems needed to turn both the Shuttle and adjacent spacedrive into a testbed for real manned space travel.
While the Shuttle can remain in space, the Motor to be tested can be deployed as needed.

GCNRevenger · 2005-08-26 21:51:58

There is an even better place to test engines, srmeany:

right here on the ground

srmeaney · 2005-08-26 22:39:47

Not if you need to test nuclear engines in zero gravity with a crewed vessel.

And not if you need to test multiples of such engines without having to build an entirely new space vehicle.

RobertDyck · 2005-08-27 01:42:17

Remember, Shuttle's budget increased from $5 billion to $7.5 billion for return to flight, but the budget for 2006 and 2007 includes retaining it at that level. This is obvious price gouging, there's no excuse to continue to pay for work that's complete. How many previous examples have ratcheted up the price to the current level? How many costs are totally useless, paying for things long since complete? How many deliberate delays?

Engineers like to brag about modern tools, especially when bringing in engineers from former communist countries. Those tools permit very rapid analysis, calculating completing aerodynamic loads, torsional stress, or thermodynamics in a matter of minutes. Building the model takes the greatest time, often taking days. Once the model is loaded, changes can be tested in minutes. These tools are already in use and permit work in very short order. Claiming completion of an existing design will take years is just more excuse for deliberate delays to pad the project budget.

The current shuttle doesn't have GPS; after all, it's only been tested once in orbit that I know. GPS won't help if you launch from a known location into space in a matter of minutes, then GPS won't work once you're above the GPS satellites. They may get it to work reliably in the future, it's not reliable now.

If you think control systems are too difficult to redesign, then I'll do it. And yes I can. Not that it's necessary, most engine compartment systems will simply continue in Shuttle-C. As Mike Griffin said, he already has a heavy lift launch stack, the orbiter is just a 100 tonne fairing. Control system changes would be primarily changing the interface to the new computer.

As for tug functionality, why do you need to rendezvous with the payload you lift? Obviously you don't. High precision docking systems are not necessary. More robust RCS or OMS thrusters are not necessary either. Remember the total mass of engine pod, payload and fairing will equal the orbiter plus payload. After discarding the fairing the total mass moved by OMS and RCS will be slightly less. If the Shuttle orbiter can rendezvous and dock with ISS using current thrusters and current fuel stores, Shuttle-C can too.

SpaceNut · 2005-09-23 19:57:27

With all the terrain changes of elavation, this just might come in handy.

Robot Built for Climbing Alien Cliffs

An agile robot is being groomed to scale volcanic cliffs on Mars, climb down sheer crater walls on the moon, and traverse the craggy faces of asteroids.
For as much progress as the Mars Explorer Robots have made on the Red Planet, they have yet to collect samples from vertical cliffs and sheer crater walls, which contain clues to the planet's past.

Mars_B4_Moon · 2024-06-05 13:52:24

an older topic

Nuclear power back in space

the Private Sector and China looking at stations and Mars

NASA-funded pulsed plasma rocket concept aims to send astronauts to Mars in 2 months
https://www.space.com/nasa-pulsed-plasm … industries

NASA confirms nuclear-powered Dragonfly mission with a Saturn moon destination
https://www.tweaktown.com/news/97650/na … index.html

New Mars Forums

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