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Will The Next Generation of Spacecraft Land In the Water?
Reservoir Hill writes "Work is progressing on the design of the new Orion Crew Exploration Vehicle (CEV), the next generation of NASA spacecraft that will take humans to the International Space Station, back to the Moon, and hopefully on to Mars. One major question about the spacecraft has yet to be answered. On returning to Earth, should the CEV land in water or on terra firma? After initial studies, the first assessment by NASA and the contractor for the CEV, Lockheed Martin, was that landing on land was preferred in terms of total life cycle costs for the vehicles. Getting the CEV light enough for the Ares rockets to be able to launch it, and therefore eliminating the 1500 lb airbags for landing has its appeal. A splashdown in water seems to be favored."
Something i used to think of as a kid was: How about using the propulsion you get from the water for initial thrust of the spacecraft? Sort of like the effect you get from releasing a bottle of air under water, couldn't that be utilized in a cheap way of getting that initial upwards thrust, or would it be too cumbersome to make a vessel that is light enhough for it to actually float?
Pure awesomenes
Re: "Getting the CEV light enough for the Ares rockets to be able to launch it," .. the solution is simple .. buy/license/whatever the Energiya booster from the ruskies instead, and you'll have much more weight to play with.... OH sorry, I forgot, the Energiya isnt build in the correct congressional district... my bad.
As someone who worked partially on the CEV, it has been decided. it is in the requirements that Lockheed Martin furnish a vehicle that is capable of both. One of the design limitations now is that it must actually be stable in swells of up to 14 feet, which are not uncommon in the cold North Atlantic - emergency abort scenarios land all launches there during early lift-off stages. There are huge problems with ill-effects of ocean landings for crews and they really are looking to avoid it, but even with parachute and pillow systems, they are looking at potential damage,
"One if by land, two if by sea ..."
Seriously, why not just do the moon mission, then pick up the landing bags as the ISS on the way home. Better yet, why not have a specialized vehicle just for orbit-to-moon-and-back, and transfer to a special-use re-entry vehicle at the ISS?
Kevin Smith on Prince
So... I don't really understand the whole disposable crew idea. It would make sense to reuse the crew rather than feeding them to sharks after re-entry, or did I miss something.
I got a catholic block.
"landing on land was preferred in terms of total life cycle costs for the vehicles."
Landing on land is cheaper, check.
"eliminating the 1500 lb airbags for landing has its appeal"
Landing on land lets it be lighter, check.
"A splashdown in water seems to be favored."
Huh? WTF? Am I supposed to go RTFA or something?
It's much easier to hit the water, and in theory you should be able to get a softer landing on water. However, if you land in the middle of the south pacific, it's a bit more difficult logistically to pick you up from there and get you home, vs. landing on some runway with roads connecting it to the regular highway system of your homeland.
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Lockheed, the Orion prime contractor, has expressed significant reservations about carrying the heavy airbags to the moon and back -- those 1500 lbs can better be used in other ways. On the other hand, there shouldn't be a problem with the weight on the more common missions to the space station and low-earth orbit, and the ability to reuse the capsule will be far greater if they put it down on land.
The speculation in this week's Aviation Week was that they would have bolt-on airbags for the earth-orbit flights, and would recover those missions on the land, and would recover at sea for the moon-return missions.
The reentry profile for the moon missions is really quite amazing. Recently Aviation Week had an article about it, describing how to get all the capsules to recover to the same spot on Earth. Do you recall way back in the Apollo days, they always described the narrow re-entry corridor? Too steep and you'd burn up, to shallow and you'd skip back into space forever? Well...
For Orion, they plan to use a skip back into space to bleed off some of the speed coming back from the moon, and to align the craft to re-enter at the correct place to land where they want, off the coast of California. It's an incredibly audacious plan, with tolerances that have to be measured in tenths of a degree of entry angle. Very cool.
Thad
I love Mondays. On a Monday, anything is possible.
To be honest in principle I don't see the downside of a water landing. The craft has to have a sufficiently low density to float, which could increase air resistance, but a certain degree of air resistance will be needed for re-entry anyway, too little of it and the majority of the slowdown will occur in lower ( i.e denser ) parts of the atmosphere. You want to decelerate over as long a distance as possible tor educe the requirements on the heat-shield. I guess you must test the whole thing for water-compatibility, but if it is to deal with vacuum, intense heat, and solar wind, I would imagine it should be able to deal with some water. I suppose there may be investment costs associated with developing new technology for water based landings, but it does seem like it should be the easier and more fault-proof way to do it, so I wouldn't be surprised if it will work out cheaper in the end.
What I don't get is the continued use of rockets. Is going straight up (the brute force & ignorance method) really the most efficient method of getting up there ? Isn't an approach like SpaceShipOne uses more efficient in terms of amount of energy needed per kilo of launched mass and thus costs ?
"eliminating the 1500 lb airbags for landing has its appeal"
"Landing on land lets it be lighter, check."
The airbags are used for landing on LAND.
They are not flotation devices. Any thing that can fly is going to light enough float on water if it doesn't leak.
The airbags are to reduce the impact.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
I'm 111% confident that it cannot land in water.
Because it's water, not land, DUH!
You can't take the sky from me...
For the folks saying "use the ISS!': Won't work. When coming back from the moon, the approach speed is far too high to enter the orbit that the ISS or any other reasonable future space station is in. The braking is done through friction as the spacecraft enters the earth's atmosphere, and provides MUCH more delta-v than would be feasible by using rockets.
To use the ISS, the spacecraft would need to perform a complex aerobraking maneuver (basically, a partial re-entry), then have the fuel needed to circularize its new orbit so that it can rendesvous with the ISS. By the time this is done, the design for the capsule is far heavier than the 1,500lb penalty that airbags impose.
My idea, make the water landing a known 'capsule loss' scenario, the same way it is with the Shuttle. If things go _so wrong_ that a water landing is unavoidable (say, launch failure) then design the capsule for quick-egress after a water landing. Airplanes ditch in water and people have time to get out before they sink. My Piper Cherokee will float long enough for me to climb out onto the wing, and for a real shock look at the survival training that helicopter passengers go through in the military, that's some pretty intense worst case scenario stuff.
With Rogallo steerable parachutes, landfall should be available at all times except the first few minutes of launch. Skip the airbags, make the capsule so it stays afloat just long enough for egress, and train the astronauts on how to get out fast.
Spaceship one was good for getting to the 'edge of space' and back. Being in orbit is a different thing. As a general rule, it takes 30 times as much energy to get into orbit as it does to just get up there. ( the number varies with altitude, of course, but 30 is a good back-of-the-envelope approximation ). The energy that has to be bled off when coming down is roughly 30-fold. So spaceshipOne is not even close to being able to do it. It requires new materials and/or a new design. Or stick with the high maintainence and unpleasant failure rate of the shuttle.
Or you can stick to the simple way of doing it with rockets and parachutes.
Oh, good lord. What Energiya would that be? The prototypes corroding away somewhere, never having been launched? There is no such thing as an Energiya, aside from old photos with a Buran attached, and some blueprints. You'd do better to start from scratch than with Energiya plans.
And of course, you overlook the many domestic alternatives that *actually exist*. Like EELVs (Delta and Atlas). Or those that could be restarted since they just quite making them a few years ago (Titan IV - roughly equivalent to a Saturn 1B).
Brett
A brain dead simple answer would be to use direct launcher http://www.directlauncher.com/ as the crew launch vehicle. Direct launcher makes use of existing four segment srbs and existing RS68s plus it lifts 50tons in it's most basic form vs 25 for Ares I mass problem solved and 2 billion saved on Constellation. The only answer I can think of right now is the fire Griffin it's the only way to save the project. That or kill Orion outright and give all the budget to COTS type programs. I see no hardware for Orion yet but spacex is now building and testing falcon 9 and Dragon.
While Netcraft may or may not confirm it, the real truth is that this program is in a death spiral and is well on its way to cancellation, just like every major NASA program to replace the shuttle over the past two decades (SEI, NASP, X-30, X-33, X-38, OSP). For the gory insider details, read the recent GAO report, or the forums at nasaspaceflight, or the postings at spacepolitics or the rocketsandsuch blog. To sum it up, Ares I doesn't have enough performance to lift the Orion, so systems are being discarded off Orion to try and get its weight down - including safety and backup systems, and systems critical to containing operational costs such as the airbags for touchdown on land. NASA thinks they have a 65% chance of getting this system operational by late 2015 if they get enough funding, but the congressional GAO is recommending that NASA postpone the program indefinitely until its problems are resolved.
Sadly, NASA already have existing medium lift (Delta IV, Atlas V) and heavy lift systems (STS via DIRECT SDLV) that could be modified for launching crews at a cost that would be a fraction of the Constellation plan. But heckuva job Mikey G at NASA won't budge from his over-budget, behind-schedule, and under-performing vision. In the process, he's going to end NASA's manned space flight program for at least the next decade while we recover from this debacle, and he's throwing away our once in a generation chance for a new launch system that will enable manned exploration of the Moon and Mars.
Check out the directlauncher.com site to see what NASA should be doing, and once you've realized how maddening this situation is, write your congresscritter about it.
The moon and the ISS are orbiting in planes 45 apart. It would require a prohibitive amount of fuel to get from the moon to the ISS. They'd pretty much need another fuel tank and another pair of solid rocket boosters to get there.Seriously, why not just do the moon mission, then pick up the landing bags as the ISS on the way home.
Traveling in space is not like traveling on the ground. On the ground, if you want to go somewhere, you only have to move to its position. In space, getting to a given position is the easy part; it's getting to the right velocity at that position that is hard.
For instance, if you want to go from Earth to the Moon, you can do it with no fuel whatsoever if you don't care about your starting or ending velocity: a Hohmann transfer orbit lets you coast to the Moon and back without any effort at all. The hard part of the journey is that when you're in low Earth orbit, you're not going the right velocity to be on a transfer orbit; and then when your transfer orbit gets to the Moon, you're not going the right velocity to land there. You need a burn at Earth and another one at the Moon to get your velocity right.
This is not like travel on the ground. In general, you can't just accelerate your car, shut off the engine, and coast to your destination. On the ground, travel is dominated by friction and obstacles. Distance is what costs. The fuel required to get up to highway speed is tiny compared with the fuel required to travel even one mile. Because of that, we talk about miles per gallon. If you want to calculate your fuel cost for a trip, you base it on how many miles you'll travel.
In space, there are no friction or obstacles. You get up to the right velocity, coast for some time, then slow down again. The fuel required during the coasting phase is insignificant compared with the fuel required to change velocity. To plan the fuel cost for a chemical rocket trip, you base it on the total "delta V", or total change in velocity. Distance and duration don't figure into the calculation.
Changing the plane of an orbit is one of the most expensive maneuvers there is. With some exceptions (like sun synchronous orbits), there are no shortcuts: you just have to burn enough fuel to cancel your velocity in one direction and gain velocity in the desired direction.
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
Having taken the time to write all that, I'm not sure it's true now. I think it takes about the same fuel to get from the Moon to pretty much any low Earth orbit you want, including the one with the ISS in it.
:-)
Too bad. I thought that was a pretty good explanation, except that it's wrong.
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
There was a MythBusters episode about this. They were testing the myth that a construction worker falling off a bridge into water could soften the impact by throwing a hammer to break the surface tension. Their conclusion was that the change in force of impact was neglible.
I don't think it's the surface tension that gets you, it's the inertia. Still, the mobility of water means that you're decellerating from 200 MPH to zero in 0.2 seconds instead of 0.1, so it's a big reduction of force.
"Houston, we are ready for approach"
"Roger that. Approach the bean bag landing zone from 1 8 niner."
"Copy that Houston."
"You should see the Lava Lamps lighting your approach."
"Thank you Houston, Please prepare the after flight debriefing bong."
"grgrgrle"
The Kruger Dunning explains most post on
Anywhere, if you hit it hard enough.
The Kruger Dunning explains most post on
Can't we simply vote for it to land on Cowboy Neal?
Sorry, had to get that in there. I couldn't help but feel the summary was asking us for our uninformed opinion.
It sounds to me like you're talking about the requirement that has been with the system from the beginning that it be able to ditch in the ocean, regardless of the nominal landing profile. What NASA is trying to decide now is if it should normally land in the ocean and face the added recovery hassle and risk, or on land and need to accomodate the added 1500 pounds of weight plus more complexity (it will either have to discard the heat shield in flight, which may be a falling debris hazard, or have dropout panels for the airbags to deploy through). Water landing is a requirement. Dry landing is an option.
Until just recently, NASA and Lockheed had moved ahead with plans for touchdown on land. However, there's been a lot of discussion over the past two years about the need to keep the weight down. They already reduced the diameter of the capsule by half a meter to keep the capsule within the weight budget. I think also the service module is above its original weight targets, and either the SRB or the second stage performance is below its original goal.
In the discussion section of the article, someone suggested doing an air capture, much like how the Air Force used to retrieve film capsules from the Corona spy satellites by snagging their parachutes and realing them in. However, I don't think he realized that those capsules weighed a few dozen pounds, while Orion will weigh around 8.5 tonnes. NASA also planned to do mid-air capture of the Genesis capsule, which was carrying solar wind particles. Unfortunately, the parachute failed to deploy and it dug a crater in New Mexico.
For comparison, Soyuz lands on dry land in Kazakhstan. Instead of airbags, it has a set of small retrorockets on the bottom that fire just before touchdown to slow from the 24 ft/s rate of the parachute to just 5 ft/s (5.5 km/hr). I'm not sure how they deal with fire through or around the heat shield.
First, of all, imagining that one guy at the top is bringing the whole enterprise to its knees is just classic populist wishful thinking. It never works that way. Herbert Hoover didn't cause the Depression, Joe Stalin didn't by himself cause the Cold War, Alan Greenspan didn't cause the dot-com bust or the mortgage meltdown, and your Mikey G isn't by himself blocking all future progress in manned spaceflight.
Figuring out exactly how and why a program craps out is a matter for endless debate among historians, but as a general rule, it's probably reasonable to say that any government enterprise that doesn't enjoy phenomenally (and historically aberrent) high levels of public interest and support always craps out sooner or later.
So the first real problem is not who's heading NASA, but the cold ugly fact that most Americans don't give much of a hoot what NASA is doing, would rather watch American Idol than a manned Moon (or Mars) landing, and aren't much interesting in sending their tax dollars to Huntsville for umpty years so that their grandchildren can watch Right Stuffers frolic on the Red Planet. A plain fact, which most folks in the spaceflight industry strenuously try to avoid dealing with by all different types of denial. (Including, incidentally, the paranoid delusion that one single factor -- or man -- stands in the way of the type of broad and deep public support that the space program enjoyed in the brief and historically unique period between 1945 and 1965.)
But the second real problem is that a government program is almost certainly a dead-end nonroute to the kind of massive social and technological change that spaceflight enthusiasts hope spaceflight will produce. There is, actually, no recorded instance whatsoever in history of a government program doing anything more than starting off (at best) something like the colonization of other planets. The voyages of exploration during the 16th and 17th century, and the colonization of the New World in the 18th century, were weakly and inconsistently supported by national goverments: they were, in general, private enterprises, undertaken by individuals for individual dreams of wealth and glory.
That is what is missing in space exploration. There is no individual -- or small entrepreneurial organization -- path to space, and not much private, materialistic, "greedy" and "selfish" motivation for people to risk their fortunes, lives and honor getting into space. If such a thing were to emerge, then humans would naturally get off the planet, not only without any need for massive government programs, but probably in spite of government efforts to stop them. (It would be like MP3 file sharing. Notice no government program was required to get that going? Because it's intrinsically easy? Or because people really want to do it? I'm guessing the latter.)
But until that kind of broad interest emerges, I don't think any amount of government exploration is going to be anything more than expensive entertainment. (Mind you, I don't object to the entertainment, but that's because I personally would, weirdly, rather watch a manned Moon or Mars landing than every first-class gee-whiz movie that will be made from now to the end of time.)
It's worth asking whether government can prime the pump, so to speak, and make it easier for private enterprise and individual ambitions to get into space, so that people can start to get turned on to the whole business, and a broad and deep urge to go can emerge. Maybe it can. Unfortunately, probably step #1 is to back off the goofy noble selfless we came in peace for all mankind aura that clings to the endeavour nowadays, which merely serves to cut it off from the range of activities normal, non-selfless, non-noble people do everyday and think about doing tomorrow.
if the accuracy can be improved they could land in the great lakes. That at least stops the salt water corrosion. The capsule can be designed for crew survival on land, and capsule survival in fresh water, if you miss you just lose the capsule and some of the internal systems, if you hit the lake all of it gets used. If problem is detected early, just aim for the ocean. in every case crew should survive.
Rod