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Excessive vibration made Da' Stick unsafe for human space flight. No way to resolve it. One design decision for Orion was to make it excessively heavy in the hope that the waight would dampen vibrations from Da' Stick. They had to add a large liquid fuel upper stage to help dampen vibrations. They still hadn't solved it. It can't be solved. Flying a human spacecraft on a giant solid rocket always was a bad idea. ATK argued that their rocket (Ares I) was safer than either EELV because it was based on an SRB; the same SRB as Shuttle. But Shuttle had a 104 tonne (landing weight) orbiter, plus a giant liquid fuel external tank to dampen vibrations. Putting a capsule on one of those things would never work. Altas V or Delta IV was always safer.
Can't be solved? Can't is a pretty strong word. Yes, the orbiter and ET were mighty hefty whereas Orion is svelte by way of comparison. Rather than even worry about dampening vibrations, why not design the capsule to accommodate vibration? My understanding is that someone had the bright idea to strobe the instrument displays at the same frequency as the vibrations by attaching an accelerometer to the seats to sync the display with the vibrations. Isn't that useful in other ways?
Um, what? Are you kidding? Every human spacecraft has a launch abort system of some sort. Gemini had ejection seats, like a fighter jet. The engineers who designed it were fighter jet engineers, including the engineering team lead. Dragon has Draco thrusters in capsule sides. They double as landing rockets. If used for abort, Dragon must use its parachute. CST-100 will use main thrusters of its service module for launch abort. Orion needs a launch abort system of some sort.
No, I'm not kidding. Abort into what? Burning propellant?
- The Apollo abort system was never used. One of the Apollo astronauts actually stated that he moved his hand off the abort controller and would rather have died than accidentally hit the button.
- The Apollo I capsule killed the crew with fire. No abort system would have saved them.
- The only Space Shuttle lost during ascent was utterly destroyed in less than a second, but according to some at NASA the crew survived the explosion and died on impact with the ocean. All of the training they received teaching them how to bailout didn't help.
The idea of being able to escape from a malfunctioning rocket is quaint and maybe it's some sort of psychological aid to the people inside, but it's also a bit unrealistic. Riding atop millions of pounds of propellant is inherently dangerous. You either accept the danger and move forward or you don't get in the cockpit.
On the topic of man-rated systems, if you put me atop a Delta IV H in an Orion capsule after the second or third flight, presuming all unmanned test flights were successful, I'd have no issue with that, even though the Delta IV H is not "man-rated" and the capsule has no launch abort system. I understand the risks and I understand the inevitable outcome if the rocket malfunctions during ascent.
Reality says your chances of escaping from a malfunctioning rocket are slim, with or without an abort system. Only one successful launch abort has been made in the history of manned space flight and it wasn't from an American rocket.
SLS cost depend on how you fudge the numbers for what is considered developement to steady state launch em costs and for how long....
As we could look at the money spent on constellation, orion and its only launch for demonstration as a 10 billion shot as that has been all that has happened and that was not even on the Da' stick (Ares I).
I rather liked the Roman candle.
I don't buy the argument that Ares I would not have been ready for a manned flight until 2017 or cost as much as SLS. Orion development may have held up a manned flight until then, but not Ares I.
I also have a hard time believing that Ares I would cost more than the STS to fly if one per year were launched.
Last but not least, if the marginal cost for additional launches was really $138M or anything close to it, that's a bargain.
They could probably have deleted that expensive and heavy launch abort system, too.
NASA hardly even mentions Nuclear propulsion even in passing anymore and only in the scope 'advanced propulsion' indicating they are not married to Nuclear, the trend is ALL towards SEP, a technology that NASA continues to invest in, use and improve upon. . Their is no long any mismatch between where the rhetoric and the development action is on the part of NASA. That mismatch existed in the 90's but it's gone now, people need to get with the times and look at what NASA is doing now, not what they remember from decades past.
Whether NASA talks about nuclear thermal rockets or not is irrelevant to its suitability for use as a propulsion technology that dramatically reduces propellant requirements. SEP isn't going to appreciably lower the mass of the types of interplanetary transit vehicles NASA has proposed in the near term. I realize advancements have been steadily made in solar panel power density, durability, and electric propulsion hardware and I think NASA should continue its work on SEP. It will work quite well for LEO space tugs to get rid of space junk/debris and small interplanetary probes that don't transit very far beyond Mars. It's ultimate suitability for propulsion of manned spacecraft is limited in ways that nuclear propulsion is not.
Aerobraking requires a light heat shield. You call it heavy, but as you just pointed out, only GCNR has sufficient thrust and Isp to make propulsive capture lower propellant weight. And GCNR will take a lot of development. NASA is currently working on a carbon fibre parasol for aerocapture and aerobraking. So that technology is already in the works. Yes, I would like GCNR, but it doesn't look like it's happening.
I meant aerocapture into Mars orbit, an aerobraked descent to the surface is an architecture feature I assume will be implemented irrespective of how the cargo landers or crew transit vehicle are inserted into Mars orbit. If the parasol proves its feasibility, then there's no requirement for GCNR's, but GCNR's make propulsive capture possible using hardware that would or should exist if SLS development tracks the way it's supposed to, something that's also a big question. You have to pay for capture with mass. The only question is how much mass.
In "updating Mars Direct", I came up with a list of equipment necessary to use Dragon as Earth Return Vehicle. Red Dragon is supposed to use its Draco thrusters to land on Mars. But the life support upgrades I list will also be necessary.
I'm assuming propulsive capture of the transit vehicle and return to Earth aboard the transit vehicle instead of further modifications to Red Dragon to enable it to do more than function as a crew transfer vehicle and lander. The crew can obviously withstand six to nine months of microgravity, but why subject them to that and confine them to a capsule for that length of time? I want them to be ambulatory for their ticker tape parade.
Mars Direct requires 2 SLS Block 2 launches. Actually, 3 for the first mission, plus 2 per mission thereafter. That's because a second ERV sent behind the hab. And Mars Direct uses direct entry for the ERV, aerobraking for the hab. And includes artificial gravity for the transit to Mars, using a tether. But zero gravity for the return to Earth, in a capsule as small as Dragon. My discussion "updating Mars Direct" proposes actually using Dragon for that.
I'm trying to keep the number of SLS flights down to something NASA could afford over the course of the first mission.
Then there's my alternate mission architecture. I call it "Mars orbit rendezvous". One person on this forum asked Robert Zubrin about it, and he reports that Robert Zubrin used the name "Hybrid Direct". That's because it takes elements from Mars Direct and NASA's DRM. It's flattering that Dr. Zubrin himself gave a name to my mission architecture. Mine uses a reusable craft to travel from ISS to Mars orbit and back. That reusable craft can be a lot more spacious, and dedicated for in-space operation. One option is artificial gravity, using the same system as Mars Direct. Updated launch requirements are here and here. I'll copy the list of launches for the first mission for one option:
- 1 SLS Block 2 for MAV (direct launch from KSC to Mars surface)
- 1 SLS Block 2 for lab & pressurized rover (direct launch)
- 1 Falcon Heavy for ITV
- 1 SLS Block 1 for TMI stage
- 1 Falcon 9 for lander & unpressurized rover
- 1 Falcon 9 for Dragon
I hadn't even considered the use of chemical propulsion because the penalty for using it is so high that I don't think there will ever be a Mars mission if that's all that's available. I don't have a problem with using chemical propulsion, but NASA wants magic pixie dust to reign down from the sky and miracle an efficient flight rated nuclear power and propulsion solution into existence. NASA is also insistent upon using massive cargo landers and transit vehicles and any proposal to use simple technology intelligently or smaller vehicles, like capsules on counterweighted tethers, seems to fall on deaf ears. NASA clearly wants to use nuclear power and propulsion but has no credible way of funding it. That is why I want Orion cancelled so badly. GCNR's are gateway technology. Orion is a supermassive black hole that is hungrily sucking away at all available funding that could be utilized for projects of broader application than propaganda campaigns.
Any asteroid mission is *NOT* any sort of preparation for Mars. Remember Mars requires less propellant to reach than the Moon. That's because direct atmospheric entry and landing requires a lot less propellant. If you want to stop in Mars orbit, then aerobraking. The Moon has no atmosphere, so full propulsive landing is the only option. Mars has gravity, so no body degredation due to zero-G/microgravity while on the Red Planet. The atmosphere means no micrometeoroids. And the bulk of the planet shields against radiation for half the sphere surrounding, and atmosphere greatly reduces radiation from overhead. Mars has ready resources to produce propellant, and can be used as backup for air and water. Yes, you can make oxygen from the CO2 atmosphere, and soil permafrost can be melted/filtered. The surface of Mars is the safest place in our solar system, second only to Earth.
Rob,
We've been given lemons and I'm trying to make lemonade.
If NASA can prove that humans can live in lunar orbit for a year and then in deep space for two years on or near the surface of an asteroid, then we've accomplished everything but living on Mars, ostensibly a far easier than living on a space rock for an equivalent length of time.
Yes, the propellant requirements are different. The technology to make the transit is the same. The technology for going to/from and living on the surface of Mars is obviously different. Once Red Dragon is man rated, we'll have spacecraft capable of making the landing. NASA has no money in their budget to develop a lander, but SpaceX does. Give SpaceX some time.
A lot of engineering is required for landers and there is no serious effort at NASA to develop the capability. In the interim, if NASA takes the asteroid mission seriously, the feasibility of deep space transit is proven.
Aerobraking requires heavier heat shields than propulsive capture. If NASA develops GCNR's, then the risks involved with aerobraking and the weight penalty associated with a heavier heat shield won't make sense. Assuming fuel efficient GCNR's are available, and it is most definitely not pie-in-the-sky technology, the weight of the heat shield required for aerobraking would exceed the weight of propellant required to propulsively capture.
To explain what AC did to Mars DRM 5.0 using solid fuel NTR's, the weight of the cargo lander heat shields increased from 10t to 40t. The weight of the cargo lander and propulsion module would be beyond the capability of the evolved SLS platform at that point. If the payload and propulsion modules were each at or below 110t, then we're talking about something an evolved SLS could reasonably lift, with margin.
GCNR's also eliminate the need for the wacky truss structure, LH2 drop tank, and contingency supplies canister. We're down to 6 SLS launches spread across 4 years along with 2 Falcon 9 launches to deliver the crew and two Red Dragon spacecraft to the Mars transit vehicle. That's conceivably within NASA's budget, whereas 7 or more SLS launches is probably not.
The massive amount of money required for development of Orion is killing everything else, including this near term asteroid mission, and I'll be a monkey's uncle if it flies with humans aboard before Dragon does. As I've indicated in my various posts about ET repurposing, STS had more utility than Orion ever will and somehow each flight costs less. I'll never figure that out, but whatever. SLS was and is expensive but it's necessary for sizable payloads. The GCNR development maximizes payload and eliminates the necessity for aerocapturing.
Apparently, a Eugene Smith from Northrop Space Laboratories already thought about a mission to Eros in 1966 as a way to prep for interplanetary space travel. I guess I should have done some more googling and then I would have known that. Better late than never, I guess. All I did was look at space debris that was reasonably close to Earth but far enough to simulate a Mars transit, solid enough to land on, and supposedly rich in ores that could be mined.
Anyhow, it's solid or relatively solid and apparently the NEAR Shoemaker probe mapped and landed on it- didn't know that, either, but once again, Google is your friend. I still think another probe is required to confirm and to determine the existence of any other debris that might interfere with the mission, but with money tight I'll concede that that's probably not necessary.
Instead of wasting money going on a joy ride around the moon for the first manned Orion mission, this is what our return to deep space using Orion will involve:
1. A Bigelow Aerospace rotating transit habitat, based on the mark 1 model 0 wheel, capable of spinning up to provide 1G, will be launched into space on the maiden flight of SLS and injected into lunar orbit using EDS (or ICPS or whatever, I don't care how the hardware gets to where it's going as long as it gets there). If the launch is successful, then further aspects of the mission proceed. If the launch is not successful, then no Orion capsule is lost.
The J-2X test stand will finally have a reason to exist. There's nothing like getting some bang for your bucks.
We all know that a deep space habitat is a requirement for space exploration, so the first launch sends equipment for the upcoming mission rather than Orion. NASA should not hazard an expensive Orion capsule on an untested launch system when an object of suitable mass and lesser cost can be utilized that would also enable a follow on mission.
2. The second unmanned test flight of Orion will use the Delta IV Heavy or Falcon 9 Heavy, preferably F9H so an upper stage can push Orion to the moon. No more of this "We must use capsule X with launcher X and capsule Y with launcher Y." If we have major issues with any of our launch systems, that should not prevent our spacecraft from using a different launch system until we can determine the cause of the problem. For normal operations, Orion uses SLS. For the SLS flight test phase, we're using proven rockets.
3. Orion will be injected into lunar orbit by the second SLS/EDS flight, the first manned flight of SLS. I want that transit habitat to sit there in lunar orbit for two years between launches to prove its durability and thus suitability for manned space exploration. Most of the current NASA Mars DRM's that I've seen use inflatable transit habitats, presumably provided by Bigelow Aerospace. Well, we're going to determine in no uncertain terms whether or not the things work as advertised.
4. Orion docks with the transit habitat and a 1 year occupation of the habitat follows to test the life support systems and to train the crew to patch holes in the space habitat and repair systems so that whereupon testing has been completed, NASA has some experience for the upcoming two year mission to 433 Eros. If there are issues with Orion or the habitat, then if Orion is disabled the habitat keeps the crew alive until a rescue mission can be attempted. If the habitat is disabled, then the crew can use Orion to return to Earth.
5. So as to provide at least a minimal science return, this habitat will be outfitted with instrumentation to record the effects of radiation over the duration of the mission.
This mission will be filled with tests and drills to prepare NASA for the challenge of spending a couple years on a large asteroid in deep space. Basically, this is the shakedown mission. If anything fails here, there's a much better chance of the crew coming home alive.
While all of this mission prep/test takes place, NASA and LANL get hot on flight rating a small nuclear reactor based on LANL's new spacecraft power design to provide heat and power. We simply must have more than one power source for our asteroid intercept mission. We're going to take both systems with us. If either is damaged or fails, then we have redundancy in the form of a completely different system that has different failure modes.
Ok, I gave this a second thought and now I have a proposal that's a slight modification of NASA's ARM. I was angry at first because the mission isn't going to Mars, but I got over myself.
My proposal is a taxing two year deep space mission to 433 Eros that validates that we have the right stuff to make the journey to and from Mars before we devote money to expensive landing hardware.
We can't retrieve this asteroid due to its size, but we can take samples and use a SEP powered satellite to map its surface and any debris surrounding it caused by its orbit, rotation, or sublimation to mitigate the danger of maneuvering a manned spacecraft so close to an object that could and probably does have smaller objects surrounding it that could potentially damage a spacecraft.
At its closest, 433 Eros is less than half the distance between Earth and Mars, but it's still far enough away and the mission duration commensurate with an interplanetary mission. This particular space rock is large enough that a spacecraft of sufficient mass could orbit it, but gravity is also weak enough that a full blown purpose built lander like Altair is not required. Orion could easily have its service module modified with lightweight landing support struts to permit a surface visit.
Here's what we get from this mission:
The meat - 433 Eros is thought to contain an enormous quantity of alumina and rare earth metals, based on data collected in 1998. Our samples will either confirm our suppositions about the composition of this body or demonstrate that we don't know what we think we know about asteroid composition and hopefully improve future sampling missions to accurately infer what certain asteroids are comprised of.
The potatoes - The astronauts on this mission will be exposed to SPE's, GCR's, micrometeoroids, thermal extremes worse than anywhere on the surface of Mars, and will spend a significant portion of their mission in deep space. Make no mistake, this is a severe test of the capabilities of our Orion spacecraft, transit habitats, and propulsion systems where even small mistakes have extreme consequences. The more I think about this, the more I like it. Everything from mission planning, software and sensors for flight maneuvers necessary to perform course corrections and debris avoidance, closed cycle life support, astronaut endurance, and even the use of a small nuclear power device to keep Orion and the space habitat livable would be included.
The gravy - Virtually everything but an atmospheric descent/ascent is accomplished if this mission is successful. I think we've already proven that we can do atmospheric descent/ascent fairly well.
Bonus - If it turns out that this particular space rock is, in fact, rich in metal ores required for the construction of spacecraft then all those smart young high school and college kids are going to have their chance to submit proposals to NASA to design and construct an asteroid mining setup that proves our ability to complete complex industrial processes in deep space.
This mission is basically an economical way to demonstrate deep space transit capability required for interplanetary missions and has a valuable scientific return that could have future implications for the use of space-based resources.
If we're really interested in studying some space rocks, there's this planet that's even closer than the main belt that has these two giant space rocks orbiting it named Phobos and Deimos. Taking some samples from either of those rocks might be interesting. I can't speak to the feasibility of putting either of them into lunar orbit, but I'm pretty sure that they're fine where they are.
Rob,
If ULA and the Air Force have any desire to continue to fund the Orion program for military space flight operations, that's fine. I expect some of the development of the systems for Orion to be incorporated into the refurbished orbiters. The money not wasted by NASA on CST-100 and Orion can be utilized to reactivate STS. The money expended by NASA to fund development of the capsule systems is not a total loss, either way.
Boeing and PWR can continue to support STS and SLS, at one and only one facility controlled and operated by NASA, preferably KSC. This means that the manufacturing facilities and test stands for the RS-25, RCS/OMS, avionics, the robotic weld tool from MAF that produces the ET, and virtually everything apart from the SRM's would be moved to KSC. Moving the SRM manufacturing facilities to KSC is probably impractical.
The STS program was so expensive, as the SLS program is and will be, because of the number of facilities dispersed across America. The movement of components from building to building at one facility is an entirely different operation than moving components across a continent.
The government can never let contractors on cost plus contracts decide how and where to execute operations. There's no incentive for them to deliver on time and on schedule. Run the programs, but run them intelligently.
If Orion is permitted to exist, NASA will go ten years, and most likely more than ten years, without a manned space flight capability of any kind.
There's no clear reason to cancel SLS, absent comparable capability at reduced cost, simply because Orion is cancelled. The lift capability lost with the retirement of Saturn V should have been a painful lesson for NASA. The mistake doesn't need to be repeated twice.
If I could undo the stupidity of it all, STS would be cancelled and Ares/SLS would never have existed. Instead, a practical approach to restoration of heavy lift capability would have been instituted. The LOX/LH2 propulsion systems that NASA and tree huggers love so much would have been replaced with simple and practical pressure fed LOX/RP-1 boosters with aerospike nozzles.
My proposals are directed at salvaging a manned space exploration program in a practical way because NASA and their favorite contractors have engineers who continually attempt impossible tasks to demonstrate how clever they are, rather than how efficient and economical their solutions can be.
You have to ask why there is an OMS-1 burn at all. That is so Shuttle can jettison ET on a trajectory for safe disposal in the Indian Ocean. For normal operations you wouldn't stop the core stage there. Thrust to apogee makes sense. The Orbital Manoeuvre System should only be used for circularization. That means "direct ascent". So looking at the whole system, you wouldn't continue with a flight profile that is modified for ET disposal, then tack on an additional booster to prevent disposal.
Okay, my mistake. I was not clear. I was trying to imply that I don't want to change any OMS burns. I want the ET well clear of the orbiter prior to any circularization of their orbits. The ET costs $50M. That's a lot of money for a throwaway gas can, but it's pocket change compared to the cost of an orbiter and probably costs less than the training for the astronauts.
You're looking at the material as raw resource. Bureaucratic management does not think that way. They see manufacturing as some mysterious black box. They can't conceive of repurposing equipment. They certainly can conceive of any sort of industrial work in zero-G. But there are also scientists. They find industrial work even harder to understand. They may be "technical", but I've attended conferences. Watch the TV show "Big Bang Theory", look at how the character Sheldon treats Howard. I've seen it; it happens. Any responsible use of resources is beyond their comprehension.
Yeah, there's a difference between having lots of information and having wisdom. A scientist probably looks at the disposal of the ET's as a $15M-$25M loss of materials over 30 years and thinks to himself, "Compared to the cost of the program the cost of the materials was nothing, so who cares if we dumped them in the ocean." An engineer looks at the same situation and thinks to himself, "These things aren't cheap to make, but we can manufacture them at a rate sufficient to meet consumption and using them for anything else isn't practical, so why would we try to reuse them?" An economist looks on, aghast at what he sees, and thinks to himself, "Whoa there, Buck Rogers! We're dumping $50M gas cans in the drink after less than ten minutes of use, to say nothing of the truly monumental cost of putting them into orbit in the first place."
Another example: after Mars Polar Lander failed, the Mars 2001 Lander was postponed. It used the same chassis, so they wanted the problem solved before launching another potential failure. Good decision. However, once they found the problem, then didn't just fix it and launch. They lost interest and forgot about it. Then years later some scientists found it in storage, and decided to modify it for their needs. They removed all the engineering experiments, to make room for more fundamental science. They removed the radiation sensor, and the In-Situ Propellant Production Precursor. The repurposed lander became Mars Phoenix. A radiation sensor is on Curiosity, but we still don't have anything to demonstrate ISPP.
This is another prime example of how NASA is desperately trying to do anything but a real, sustainable manned space exploration program. I just want the manned space exploration program shut down or I want NASA to demonstrate a coherent and sustainable strategy that actually achieves the goal that the administration continues to talk about, but isn't really seriously trying to accomplish.
Here's what a real manned space exploration strategy looks like:
- Orion is cancelled and the useful aspects of the program, like the avionics development, are applied to STS
- A substantial portion of funds are invested into space nuclear power and propulsion technologies so that considerable payload mass versus propellant mass can be shipped to its destination
- For operational support, all far-flung contractor facilities for STS and SLS are moved to a centralized location and proper accounting of contractor activities is made by NASA so there is no guessing about where all the money is going
- STS is reactivated for SLS hardware retrieval only
- ISS receives an orbital manufacturing module or modules to produce spacecraft and modules for ISS from what would otherwise be space junk
- SEP tugs collect and repurpose space junk, expended STS and SLS hardware in particular
- SpaceX and Orbital continue to provide for ISS crew and cargo requirements
- Science experiments focus on answering questions about how humans can sustainably live in space and on other planets
Use of resources generally sounds good. But you're going to require practical processes to use those materials before anyone lets you accumulate them.
As far as an orbital manufacturing facility is concerned, you need a few smelters (there are several kinds of alloys in the ET or any other rocket for that matter, so rather than trying to come up with some overly complicated method for cleaning a single smelter after each use, each smelter handles a particular kind of alloy), machines to produce bar and flat stock, two or more CNC machines, a welding center, a machine for tooling repair, and an area for assembly (the space hangar that NASA wanted on ISS). Apart from that, a robotic disassembly station is required to break down spacecraft parts into pieces small enough to fit in the smelters.
I'm not suggesting that every part of an ISS module or lander be built at ISS, rather, using the repurposed materials, the heavy shells can be assembled on orbit. Supply vessels can provide workers and unique items requiring complicated manufacturing or assembly techniques (like computers, wiring, engines, for example). The parts of the supply vessels that are discarded need to be repurposed, too.
It simply costs too much to trash the materials or working spacecraft parts once you spend the money to get them to orbit.
Your channeling Zubrin's 'Mars or Bust' mentality which is dead-wrong. We don't have the financial or technical ability to go to Mars now, interim missions of SOME kind need to happen to build a Mars capability. If Asteroid visitation is a good/bad interim mission is another topic, and I'd argue that it is simply the only interim mission the the current SLS/Orion combination is capable of doing, so if we don't want to do it we should just cancel both vehicles right now.
Of course we don't have the financing or tech, Impaler. When you keep throwing billions of dollars at programs that won't directly assist with achieving the objective, you wind up with lots of program cancellations, congressional micromanagement, and no money.
Who in their right mind would, and unfortunately this necessarily excludes almost everyone in the Congress and Senate, keep forking over money to NASA's manned space program without producing a result?
Look, I like all space exploration, even exploration of asteroids. That said, the space nuclear power and propulsion program was cancelled decades ago, it's currently not being funded to the level it needs to be, and there's no non-nuclear propulsion system that could realistically retrieve an asteroid of any substantial size. If we're going to retrieve samples from a variety of small space rocks, let's use robots to do that. Set the horse before the cart.
Orion isn't a space exploration vehicle, it's a small short duration crew transfer vehicle that's every bit as expensive as the Space Shuttle and redundant. The Apollo/LEM combination could at least land on the moon. Orion isn't going to land anywhere except an ocean on Earth. If TPTB had elected to cancel Orion and fund Altair, I would have supported that decision and whatever amount of money it took to create a reliable multi-mission capable lander. A Dragon, Soyuz, or Space Shuttle could have transferred the crew to Altair and the EDS/Altair combination could have transported the crew to their destination.
I think the development and validation of a large SEP vehicle is essential for deep space exploration as that's the technology with the long term promise of high mass fraction delivery, shorter transit times and ultimately some chance at reusability in space. ARM mission thus looks to couple the 2 wasteful elements that Congress has mandated with something that's actually useful in the long run for any destination, could we have that SEP vehicle without SLS/Orion, sure a F9H sized SEP would easily validate the engineering, but this shotgun-weeding may be the only way it can happen.
Test SEP powered tugs? Sure, let's do that in LEO first. We can start by retrieving all the satellite and rocket parts strewn all over the place and moving them to an orbital manufacturing facility aboard ISS to repurpose the parts into useful hardware.
Please explain how grabbing a space rock is useful for landing on a planet. There's no atmosphere on an asteroid and we don't have any program to produce flight hardware to land on one anyway, irrespective of whether or not it was useful.
Yes, if we're going to launch a SEP powered tug then let's not break the bank doing it with SLS.
Third cent: propellant ullage. Why use a big motor like OMS to do a small motor's job? All you need is a very few hundred pounds of thrust acting on something the size of a Saturn S-II second stage. They did it back then with small solid propellant cartridge motors shaped like a thick pancake, about 5 inches in diameter, and about an inch and a half thick. There were 3 for redundancy. I crudely estimate 300 lb thrust each. Today you would do the same job with a few very small hydrazine thrusters, if you wanted something reusable. If it's one-shot, use the solid, it's cheaper and stores "carefree".
GW
I think we have a winner.
If we did it the way you suggested, then we could haul them back to ISS with a solar electric tug, suck the propellants out and use them to provide oxygen and/or water for the crew, or simply use the propellants to keep our massive station in orbit. The SOFI could be used for, well, insulation.
I was thinking. To restart the main engines, ET requires acceleration to push LH2/LOX propellant to the siphon. So rather than use OMS entirely, just use OMS to gain sufficient acceleration to push ET propellant to the siphons. Then restart SSME. And SSME was started by a silane igniter on the launch pad. However, that web page mentions "direct insertion".
Robert, you're still thinking like a NASA contractor. If there's 1% of the propellant left after STS or SLS attains 99%+ of orbital velocity, then the solution is pretty simple. The ET needs one or more small LOX/LH2 thrusters to circularize its orbit. It doesn't weigh nearly as much as the orbiter. I don't want to redesign the ET to make it a space station habitat, redesign the SSME to light off in space, or redesign the orbiter's OMS to feed from tankage in the cargo bay. All of those solutions unnecessarily complicate the design of the orbiter's OMS and SSME.
A simple pressure fed LOX/LH2 thruster to circularize the ET orbit after it's jettisoned from the orbiter is all we need. The only questions are as follows:
How much would the thrusters weigh?
Would the addition of the thruster interfere with any other aspects of the operation of the ET?
What is the optimal placement on the ET to minimize weight and complexity?
How difficult is it to pressurize the propellant tanks sufficiently to utilize the remaining propellant for use by a rocket engine that's much smaller than SSME?
How inexpensively can the system be made, accepting that it will be a single use computer controlled rocket engine that should not require a massive logistics tail to support it and need not be insanely over-engineered for the task of placing a gas can into orbit?
So direct insertion is preferable. That eliminates OMS-1, instead using the higher Isp main engines. Could the siphons be improved so there is less residual propellant? The quoted section in SpaceNut's post says 1,000 kg of LH2 and 6,000 kg of LOX left, or about 1% of liftoff propellant. Could that be used? Interesting. However, that again would lift an unmodified tank.
If we just jettison the tank as we would in normal operations and use a thruster to burn the remaining propellant, then we don't have to concern ourselves with how OMS-1 would be affected, use of specific flight profiles, improved siphons, or redesign of the SSME or OMS.
From my rough estimates, over the life of the STS program more than seven million pounds of high grade aluminum alloys were thrown away after just 8.5 minutes of use. How many space station modules or lander frames could have been built with that much material if we had an orbital manufacturing facility to repurpose these materials?
Instead of trying to concoct ways to make the orbiter or other spacecraft capable of carrying a little more payload, if everything we send upstairs is added to a stockpile of raw materials for other uses, then pretty soon all you have to provide are warm bodies.
Bolden wants to waste some more money on another impossible task that requires technology we don't even have prototypes tested for yet so we won't have money to go to Mars or achieve any other worthwhile science and exploration goals.
Planetary defense? We can't stop dumping billions of tonnes of carbon into our atmosphere every year, but we're going to "defend the planet" from space rocks? While we're at it, let's use warp drive to get there faster. Seriously though, I want some of whatever these guys are smoking.
Maybe an astronaut can determine what kinds of space suits make the best snow angels on one of these dust clods.
Has anyone else noticed that Orion is always docked to Battlestar Galactica near Mars, like some sort of hood ornament, in every one of these PR brochures, but Mars is always in the corner, just out of reach?
kbd512: When Shuttle was flying, I tried to tell a couple Shuttle engineers my idea to save cost. I noticed the windshield was hand ground every flight to remove micrometeoroid pitting. They didn't use power tools, it was hand ground. Very labour intensive. My idea was to replace the glass with ALON: Alumino-Oxy-Nitride. That's a transparent ceramic developed under contract for the US army in the 1980s for windows of tanks. It's designed to be bullet proof. Since it can withstand dramatic impacts, that should eliminate micrometeoroid pitting. Both engineers told me they had ideas to reduce labour and expense processing Shuttle. And both engineers told me corporate executives told them no; that their goal was to maximize cost to pay employee salaries and corporate profit. So people far more qualified than you or me came up with ideas, but were told to shut up.
I'm not qualified to tell a NASA engineer anything but even I, and apparently they as well, can see when something is obviously ridiculously wasteful and inefficient.
There was precious little about STS that was managed correctly. The only real "accident" that the STS program ever had was that it worked at all.
I want NASA to implement workable solutions so that there is sufficient funding for real science and exploration. Apparently that's crazy talk.
The first link posted by SpaceNut provides numbers for energy needed to bring ET to orbit. The first post says 1,514 kg of additional OMS propellant, reducing payload by that mass. The second post calculated reduced payload by 5,280.5 kg. And both calculate based on low altitude science orbit, not ISS. And that's a standard ET, not one modified to be a station module.
Yeah, so orbiting the ET would require additional OMS propellant capacity that the system doesn't have since no effort was put into reusing every part of our reusable launch system. We can't design pressure fed LOX/LH2 thrusters to circularize the ET's orbit using residual propellant in the tank because there's not enough funding for that. Throwing away hundreds of millions of dollars of hardware on every SLS flight, no problemo. It's more desirable to throw away a $50M investment than it is to make ISS module shells or lander frames from it in orbit to gain experience with orbital manufacturing and assembly. That's real applied science that has a direct application for space industrial purposes and we can't have any of that.
This is crazy talk, their is nothing to 'reactivate' the Orbiters can not be plucked out of museums and just flown, they depend on ARMIES of technicians which have been scattered to the winds, the people who designed and built it all have retired or DIED. All that money has been reallocated to NEW armies of technicians working on new vehicles, none of their new skill sets are transferable even if some political will existed to try to do that, but in fact all political will is for the current program not to try to return to Shuttle. And if we COULD somehow summon the political will to divert from the current SLS/Orion why in the name of all that is Holy would we actually want to return to a vehicle which was a complete failure on EVERY single desired performance metric.
IIRC, at its peak there were fewer than 30,000 people devoted to STS.
The people who designed Soyuz are all retired or dead. What's your point?
SLS uses SSME's (actual flight hardware from STS), SRM's (more actual flight hardware from STS), modified STS ET's (obviously not the exact same hardware, but not entirely different, either), the tiles from the orbiter's TPS (with different shapes, obviously) and Avcoat (Apollo technology), upgraded crawlers, the VAB with upgrades to supposedly make it accommodate a variety of vehicles, and the same launch pads after major refurbishment. The orbiter is obviously a unique piece of hardware but it would appear that a lot of the key pieces of technology from STS are being used for Orion and SLS.
I guess everyone who was working on STS just kinda fell off the planet, but somehow the entire STS propulsion system, less OMS, wound up in SLS.
I told you why I wanted to use it.
- A real space exploration vehicle has to have a crew delivered to it and Orion is not a real space exploration vehicle, no matter how many times NASA repeats the lie.
- At $72M per copy the SSME is not what I would call cheap, so I would rather not throw four of them in the Indian ocean with every SLS flight.
- STS is the only vehicle that can de-orbit with a substantial payload and if the nozzle extensions are removed then the SSME's fit in the cargo bay and 4 of them are just below the weight limit for the orbiter to land with if the landing gear are upgraded.
Shuttle was DANGEROUS, EXPENSIVE and INFREQUENT, the SLS/Orion while it is likely to be just as expensive and infrequent will at least be safer by virtue of being a capsule with launch abort systems.
How is it that Orion, using the same propulsion system with software upgrades, is far less dangerous? Because it has an unproven escape system strapped to it? An in-line launch configuration is preferable to side mount because it can't be struck by ET FOD, but SLS has not been proven to be safer than STS or any other launch system.
For around $18B, we're getting a tuna can with an escape rocket on top of it? Oh joy! Can we take a ride on that escape rocket right now so we have money for payloads that actually require SLS?
Imagine all the funding we could have for worthy SLS payloads like an orbital manufacturing module for ISS or a real manned space exploration program. I guess new toys are more important than science or exploration.
The reactivation of STS need not be a death knell for space exploration. We can retain STS to do what little good it does, have commercial crew and cargo transfer vehicles to service ISS, use ISS as an orbital manufacturing facility to reclaim the materials in the STS and SLS ET's, and use SLS to lift cargo required for a real manned space exploration program. Consolidation of facilities and elimination of non-essential programs is the key.
The cost of STS was driven by permitting contractors to operate support facilities all over the country. If NASA had mandated that all flight hardware be built, tested, and launched from one location, then the number of employees required to maintain facilities, contractor travel costs, and hardware transportation costs plummet. Head count for redundant operational support also plummets.
Man-rated flight hardware that's available right now and not years into the future, if and when it's development is completed- something that is entirely dependent upon political support, is what we should use. NASA doesn't have a manned space program right now because the obvious issues with STS, Ares/SLS, and Altair/Orion were ignored.
Although some useful upgrades were incorporated into STS, a lot of equally important cost reduction measures, head count reduction measures by any other name, were never implemented. The orbiter TPS immediately comes to mind. If JPL can design robots that drive around on Mars, then it can sure as heck design a robot that lays ultra-lightweight sand bricks back here on Earth.
There are some limited instances where it's desirable to have a crew service a payload, and STS was designed for that. To my admittedly limited knowledge, NASA doesn't have the technology required to travel back in time and smack the decision makers who created requirements that forced STS to be the kluge that it was upside their heads. So, as long as we have lemons we make lemonade.
The two "accidents" in the STS program were more willful ignorance on NASA's part that resulted in destruction of flight hardware. Those kinds of things happen when you ignore your engineers.
If LANL can fabricate a new class of reactors for satellite power in less than a year and for less than a million dollars, then for a few billion not wasted on redundant capsule systems, I'm quite certain that a gas core reactor is in the cards for us. That's where I want our development dollars directed. VASIMR and other NEP technologies may be entirely feasible once nuclear fusion is perfected, but let's not hold our breath waiting for that to happen.
Getting back to the question posed in the OP, can we use the uber gas cans as raw materials for construction of ISS modules or Mars landers from an orbital manufacturing facility aboard ISS? I think so. If the money has already been expended to push the ET's to orbital velocity, then dumping them into the ocean is egregiously wasteful. So what if some gas is required to circularize the orbit? The gas can still has around 1% of the gas in it at MECO. Is it an impossible engineering task to develop thrusters to convert that residual to a circular orbit?
The core stage of SLS will never achieve orbit. It's a big dumb rocket. Even though SSME was designed to be reusable, SLS will never be able to deliver its core stage engines to orbit.
Wait. What? I thought SLS Block I without an upper stage was supposed to push 70t to LEO. Is that incorrect?
Second, SLS practically is the Ares rocket from Mars Direct. In fact, from what's posted online, designers are considering 5 main engines for block 2. So with 5 SSME in the core stage, a pair of J-2X for the upper stage, and a pair of SRBs, that is Ares. The only difference is 5-segment SRBs instead of 4-segment. One option I wish they would consider is 5 SSME with 4-segment SRBs. That skips the vibration problem with 5-segment boosters.
Would composite casings mitigate the vibration problems with the 5-segment design?
One design feature is to use 4 RL-10 engines instead of a pair of J-2X. Interesting: J-2X produces 1307 kN thrust (133,276.9 kg force), Isp=448s. RL-10 produces 110 kN thrust (converts to 11,216.878 kg force, but you should round off to 3 significant figures), and Isp = 450 to 465.5 seconds. Why is Isp in vacuum a range? So 4 RL-10 engines provide much less thrust, but a little better Isp. If you burn those engines longer, could it provide more delta-V? That's one thing they're talking about.
From an engineering complexity standpoint, is there a good reason why right-sizing the core stage design to achieve the desired throw isn't preferable to adding a stage atop the core stage? Most efficient? Obviously not, but what insane amount of money will be required for a man-rated second stage?
Separating cargo from crew is generally a good idea, but we need a launcher for crew. SLS is that launch vehicle.
I agree on the first point, but SLS need not carry crew. We have existing hardware to blow mad money on LEO transport service. If each Orion/SLS flight costs just as much as a Space Shuttle flight or more, then Orion has no purpose, apart from preventing development of real space exploration hardware.
Here's why I want to do this.
- Increase flight rate to maintain workforce and its proficiency at manufacturing flight hardware
- Skip RL-10/J-2X/DUUS/EUS and other upper stage acronym soup chemical engine development to ensure funding for gas core nuclear rockets, nuclear power solutions for exploration vehicles, and methane powered engines for Mars landers is available
- Gas core nuclear rockets eliminate the need for heavy aeroshells required for risky aerobraking maneuvers to achieve Mars orbit and the attendant weight of propellant required for Mars orbital insertion, thus keeping individual SLS payload weights within a margin that SLS with advanced SRM's could realistically achieve
- Ensure continued availability of funding for advanced long term storage of cryogenic propellants for the nuclear rockets
- Provides both reason and utility for the continued existence of ISS
- NASA could partially fund development of Dragon Rider for propulsive landing of crew on Mars so the cargo landers would not have to be man rated or require separate designs for cargo-only versus crewed landers
I still want to retire STS and SLS, but at a time when their capabilities are no longer of utility to our manned space program.
I think that the STS program should be re-activated immediately and all orbiters refurbished and upgraded for a specific purpose, retrieving SLS hardware and orbital assembly and servicing of payloads launched on SLS.
Somehow the various contractors will make Orion's development and use every bit as expensive as the far more capable Space Shuttle. Orion was developed for a manned lunar program that no longer exists. It has no purpose for a Mars mission. The proposed lunar fly-by stunt is just that.
If it were up to me, I would follow most of the recommendations proposed for the Space Shuttle upgrades. Specifically, the avionics and fuel cell upgrades, landing gear improvements for greater landing weight, and channel wall nozzles for the RS-25's are all worthy of development dollars. Additionally, to eliminate the insane amount of manual labor that refurbishment of the orbiter TPS requires, a robotic TPS refurbishment and inspection capability should be developed. Cancellation of Orion would make available the required funding for the necessary Space Shuttle upgrades and operation.
Here's my proposal for a re-activation of the STS program:
Presumptions:
I presume no more than 2 SLS launches per year and an equivalent number of STS launches to retrieve the RS-25's. I also presume that work on the Dark Knight boosters moves forward to lower the cost of the SRM's and increase their performance. The general idea is to remove the most costly aspects of SLS (expenditure of expensive reusable hardware) and STS (labor intensive reusable components) and increase the flight rate of common hardware.
Problem:
The RS-25E development programs have to contend with the fact that RS-25 was designed for reuse and is way too expensive for use in expendable launch vehicles.
Solution:
SLS would become the cargo-only rocket that it always should have been, STS would infrequently transfer crew and cargo to ISS and space exploration vehicles, and it would return the costly RS-25's from SLS rockets.
Pre-req's:
The SLS engine barrel would require a slight redesign to separate it from the tankage and subsequently circularize its orbit for retrieval of the RS-25's.
The RS-25 would require a redesign to permit easy removal of the nozzle extension from the powerhead.
Intended Use:
The first ISS module that a STS return-to-flight mission should carry would be a machining module to repurpose the aluminum from the engine barrel to eventually construct space station module shells in orbit. It demonstrates the capability to use largely autonomous machining centers operating in microgravity to have them turn SLS scraps into construction stock for ISS or spare parts for space exploration hardware. At a later date, if it is possible to boost the entire core stage into orbit, then the capability to entirely reuse the overwhelming majority of SLS flight hardware becomes possible.
Conop:
Each STS mission would follow a SLS mission to transfer supplies or modules to ISS, take space exploration crews to their space exploration vehicles docked at ISS, and retrieve RS-25's from SLS missions to repurpose the materials from the engine barrel and eventually the tankage, too.
Goal:
ISS would finally be a space exploration mission support tool. The machining unit would turn the microgravity experiment into a space-based manufacturing facility to construct mission hardware from SLS remnants, and a staging area for space exploration crews/vehicles.
Conclusion:
I have no idea what the technical challenges would be with this solution or if it's reasonable, but the payload capacity is there if the landing gear receive the upgrades.
Apart from testing the ability of the Mars landing craft to make a landing on another body, verifying that the Mars habitat and power supply can be reliably run for a period of two to four years afterwards with autonomy, and testing of crew environmental support solutions, I see no other purpose for lunar missions.
It's obvious that no spacecraft with a few weeks worth of supplies onboard is ever going to take humans to Mars. Degrading the capability of the service module to hit mass targets for Ares I severely restricted its capabilities for lunar missions. Apart from taking humans to ISS, Orion/SLS has no practical utility at this point with the Altair program cancellation and a Block I SLS configuration that can't put that much mass into TLI anyway, so it's no better than the Space Shuttle in terms of cost and can't even perform the mission it was built for.
If NASA insists on launching Orion on a flying pork barrel, I mean SLS, then there was no reason to retire the Space Shuttle. The cost of an Orion/SLS mission will be the same as a STS mission and there's no landing craft to land on anything with, so what's the point?
NASA's Space Shuttle was not unreliable, the humans involved simply ignored the problems and the result was destruction of flight hardware.
Given the cost differential between Orion/SLS and Dragon/Falcon 9, I'd rather NASA did the following:
- Continue work on SLS, absent any other launch system with comparable capabilities; SpaceX BFR is a paper rocket at this point
- Work with SpaceX to man rate Dragon, a system proven sufficient for LEO taxi service; if Orion is man rated before Dragon I'll be suitably impressed
- Cancel Orion, as it's not required and there's no compelling reason to drag a capsule all the way to the moon or Mars and back
- Restart work on Altair and EDS with an eye towards lander and/or EDS reusability and refueling from propellant depots
- Use SLS to launch the Altair/EDS combination and propellant depots
- Put a small inflatable habitat module atop Altair instead of a confining tin can
- Work on EOR with Altair for lunar missions
If there's still money burning a hole in NASA's pockets:
- Composite tanks for SLS
- Composite SRM casings