SpaceX Falcon 9R launch

RobertDyck · 2014-04-22 23:09:08

Tom, you're talking about launch, and controlled landing on Everest. But landing with enough fuel for a second launch, then controlled landing back in the continental US. Do you realize how little launch mass is the upper stage and Dragon? Yes, it means a suborbital hop instead of obital insertion. I doubt there would be enough fuel for a second launch. And I had agonized over whether that is possible on Mars, with 38% gravity. You want to do that on Earth?

JoshNH4H · 2014-04-22 23:32:33

To be fair, he may have been discussing rocket launch from the Tibetan Plateau, which would be a much more simple hop.

GW Johnson · 2014-04-23 16:34:30

The problem with a rescue craft operating on Everest isn't doing VTOL at 29,000 ft, nor is it a suitable launch site. It is a suitable touchdown spot on the mountain close enough to do any good. That's the most hostile landscape on this planet: nothing but untrustworthy rock and ice at impossible angles. In comparison, building a helo or V-22-like craft capable of hover at 29,000 ft is easy.

GW

JoshNH4H · 2014-04-23 18:56:35

And would probably have a larger return on investment

GW Johnson · 2014-04-24 08:58:27

If takeoff from the high-altitude rescue site is too difficult because of the payload increase with all the rescued people, there is always the venerable old JATO bottle.

I'm not sure that high-mountain rescue will ever be a for-profit business, so return-on-investment may not apply. Most rescue services are operated by governments. I do think any such rescue craft will be a VTOL airplane or helicopter. There's likely to be only a tiny handful of staging bases to cover the entire range of the Himalayas, same for other mountain ranges elsewhere. The craft will need hundreds of miles worth of useful range, plus considerable on-site hover time. \

GW

Terraformer · 2014-04-24 14:59:24

Why not an airship?

GW Johnson · 2014-04-24 15:32:15

Airship? Two serious troubles: (1) very difficult to get that high a service ceiling out of buoyant lift, the density ratio to SL std is about 0.37 or so; and (2) even worse, mountain regions have very high, very turbulent winds, which are usually fatal to airships even at SL.

GW

JoshNH4H · 2014-04-24 15:50:19

Airships seem pretty feasible, seeing as the altitude record for an airship is about 30 km higher than Everest is tall (Put another way, more than 4 times higher than Everest)

Terraformer · 2014-04-24 16:04:20

Or, use smaller landers operating out of an Airship mothership.

JoshNH4H · 2014-04-24 17:13:12

Sure. Although I'd think it would make more sense to just drop rescuers down on a cable. There is the issue that airships are slow, though

Terraformer · 2014-04-25 07:24:00

Have we ever tried seeing how fast one could go?

JoshNH4H · 2014-04-25 08:25:21

I suppose we haven't. But for a high altitude flight like Everest there are speed limits related to how much structure you can feasibly have

GW Johnson · 2014-04-25 08:59:19

Maybe I was wrong about high-altitude performance of airships. Although, I doubt the ones that flew high carried much payload.

I'm not wrong about vulnerability to wind turbulence. There were 3 big USN airships just prior to WW2. All were about the same size as the Hindenberg (built by the same outfit, actually). All three were destroyed by the wind turbulence of storms, with many casualties. The wind turbulence around high mountains is much worse by far, being able to down or break-up modern fixed-wing aircraft. There's very good and lethally-important reasons jet airliners stay away from mountain peaks.

Speed: since the 1930's dirigibles and blimps have usually sized-out at cruise speeds in the 60 to 80 mph range, with max speed just about 80-90 mph. That's still true of today's blimps. That's not to say one of these couldn't be pushed faster, but you sacrifice payload for the bigger engine. With any kind of airship, weight is THE issue. These vehicles are typically substantially more fragile than fixed-wing aircraft or helicopters, just to be able to fly at all. I'd bet the high-altitude blimps are very slow and underpowered, but I'm not familiar with them, so I don't really know.

The needs of a mountain rescue craft are (1) substantial payload, (2) vertical landing/takeoff in very restricted and hostile spaces on extremely-rough ground, (3) structural robustness to resist very violent winds and extreme turbulence, and (4) speed enough to get there in time to do any good.

I submit that an airship's characteristics are not a good match with that list. A VTOL aircraft or helicopter is a far better match, but even these will have extreme troubles with rough ground and violent winds. Some sort of rocket might work, but will always be critically-short on payload because it has to carry so much propellant.

Such a craft will be a one-use design adapted to this kind of service and unsuitable for just about anything else. My guess is it would be a tilt-wing VTOL, somewhat along the lines of a really-beefed-up V-22, or a range-improved version of the much earlier XC-142. But, neither of those can/could actually touch down on the kind of rough ground typical of a high mountain, nor can/could either successfully hover in the very-common extreme winds and turbulence of that environment.

GW

Tom Kalbfus · 2014-04-25 17:08:36

I can think of another use for rockets. How about landing a Mars Hab with astronauts on board, in Antarctica for a full dress rehearsal of a manned mission to Mars.

GW Johnson · 2014-04-25 20:39:50

Why on Earth would we use a rocket to send a simulated Mars hab to Antarctica, when ships and/or aircraft can do that very same job at orders and orders of magnitude less money? And, why risk Antarctica, when almost any desert would do?

That being said, there are severe restrictions on when you can go to certain locations in Antarctica, no matter how you get there. Worst case is near South Pole Station on the Antarctic Plateau.

Darkness prevails 6 of 12 months. Winds can be at or above 100 knots quite frequently, with turbulence intensities near 30% (30 knot amplitude). And for pretty near 6 months out of 12, ambient temperatures are below -60 F, to as low as -110 F. Up in the atmosphere above the south pole, temperatures have been observed as low as -130 F, since the late 1940's. The ice is riddled with hidden crevasses, even when it has been graded smooth. Ungraded, it is fatally-rough for aircraft of any type.

Modern aircraft that use kerosene fuel with hydraulic-operated flight controls simply cannot cope with cold conditions like that, even ignoring the roughness and the crevasses, and the obscuring darkness. Both the fuel and the hydraulic fluid freeze solid in cold like that. 60 years ago, gasoline-fueled aircraft (specifically the DC-3) with mechanical flight controls could, and did, cope with it, but with extreme difficulty for the aircrews. High-power electrically-heated suits were required to survive. That's where the weather observations came from.

A better idea would be to update the 1945 design for JATO bottles. That would have a wide variety of applications in aviation generally.

GW

Tom Kalbfus · 2014-04-25 22:07:58

GW Johnson wrote:

Why on Earth would we use a rocket to send a simulated Mars hab to Antarctica, when ships and/or aircraft can do that very same job at orders and orders of magnitude less money? And, why risk Antarctica, when almost any desert would do?

You really want to try out Mars equipment in the scorching Sahara or perhaps Death Valley, or maybe even the Grand Canyon? Mars is cold, so I think we should test it out on some cold place on Earth like Antartica, see how well space suits keep astronauts warm under such environmental conditions, and the colder the better. If an astronaut gets frostbite while wearing one of the Mars suits, there is something wrong!

GW Johnson wrote:

That being said, there are severe restrictions on when you can go to certain locations in Antarctica, no matter how you get there. Worst case is near South Pole Station on the Antarctic Plateau.
Darkness prevails 6 of 12 months. Winds can be at or above 100 knots quite frequently, with turbulence intensities near 30% (30 knot amplitude). And for pretty near 6 months out of 12, ambient temperatures are below -60 F, to as low as -110 F. Up in the atmosphere above the south pole, temperatures have been observed as low as -130 F, since the late 1940's. The ice is riddled with hidden crevasses, even when it has been graded smooth. Ungraded, it is fatally-rough for aircraft of any type.

Is Mars any better than this? You save some weight by leaving the air tank behind

GW Johnson wrote:

Modern aircraft that use kerosene fuel with hydraulic-operated flight controls simply cannot cope with cold conditions like that, even ignoring the roughness and the crevasses, and the obscuring darkness. Both the fuel and the hydraulic fluid freeze solid in cold like that. 60 years ago, gasoline-fueled aircraft (specifically the DC-3) with mechanical flight controls could, and did, cope with it, but with extreme difficulty for the aircrews. High-power electrically-heated suits were required to survive. That's where the weather observations came from.

How about a rocket engine?

GW Johnson wrote:

A better idea would be to update the 1945 design for JATO bottles. That would have a wide variety of applications in aviation generally.
GW

Part of the mission being simulated would include landing on a planet. Lowering a hab in pieces and assembling it on the ground just isn't the same. We need to build a fully functioning hab, complete with pressurization, and then find a high altitude place in Antarctica in which to land and test out the space suits.

GW Johnson · 2014-04-26 08:38:18

If you insist on doing this in Antarctica, then the dry valleys are the best analog to Mars, and the weather conditions generally lack the extreme winds. It's plenty cold in the Antarctic winter to test heating. But, testing suits and other equipment against cold is just as well done in test chambers. We've done that since the first flights into space. There's a facility in Houston where they tested Apollo suits against hot/cold in vacuo.

As far as deserts go, you want a cold one, but not so isolated. Antarctica is difficult at best, logistically. The Atacama in Chile is cold enough in wintertime to provide a good field test. Outer Mongolia is another suitable place in winter. The Canadian archipelago is another place, although not so dry as a real desert. I don't know where all the suitable test sites are, but even China Lake in winter is cold enough.

GW

SpaceNut · 2014-04-26 10:28:45

I see what Tom is driving at is a safe mars simulation that is based on the devon island Mars society work along with what was done with the Mars 500 mission as a dry run for a complete mission in isloation which is what going to Mars would be.

louis · 2014-04-26 17:30:06

SpaceNut wrote:

I see what Tom is driving at is a safe mars simulation that is based on the devon island Mars society work along with what was done with the Mars 500 mission as a dry run for a complete mission in isloation which is what going to Mars would be.

My own view is we should build a full replication facility i.e. a huge hangar like building which would be pressurised to Mars atmospheric pressure. There should be Mars replica regolith (down to a depth of maybe 20feet), Mars-like temperatures and a Mars lander and hab within it. There should be a pressurised rover. Put the crew into orbit in the ISS for six months and then transfer them to the "Mars lander" - which could be a simulator. Night and day would reflect the Mars seasons.

Also the Rover could have simulator links at various point in the facility - riding on rollers on various journeys, with the simulated landscape being projected as with airliner simulators.

The cost might be a few hundred million dollars but that seems acceptable in terms of getting things right. The only thing missing would be the one third G really.

SpaceNut · 2014-04-26 17:45:29

The news has Space X suing the military on the monopoly launching of spy satelites of which a resent order for 36 vehicles through the ULA has been inked.

SpaceNut · 2014-12-28 14:35:10

We meantioned recoverability else where but is deserves to be in a Space X topic...
It will be hard for what SpaceX is attempting which is a landing of a rocket on ocean platform. With an attempt to return a portion of its next launched rocket to a small platform in the middle of the Atlantic Ocean.

More than just hitting a target, engineers are attempting to softly land the bottom portion of the rocket in an upright position, to avoid damage and allow the rocket phase to be reused. It's not the first time SpaceX has attempted the feat. The latest effort follows a string of failures -- or learning experiences.

"Unfortunately, it sort of sat there for several seconds then tipped over and exploded," Musk told attendees of an MIT-hosted forum earlier this fall -- speaking about his company's latest attempt. "It's as tall as a 14-story building. When a 14-story building falls over, it's quite a belly flop."

But Musk and his engineering team think they're getting closer. They predict a 50 percent rate of success for their next launch attempt, scheduled for January 6 or 7. Pretty good odds considering the difficulty of the feat.

The rocket must not only slow down sufficiently -- breaking with its booster rockets as it speeds back through the atmosphere -- and land upright, it must also hit a moving target. The target barge is 300 feet long by 170 feet wide, and is unanchored. It's engines must work to keep it floating in roughly the same spot as it awaits the rocket.

If successful, the launch -- which was originally scheduled for mid-December -- could signal a new era of profitability for SpaceX, whose business model is counting on reusable rockets sooner rather than later.

GW Johnson · 2014-12-29 10:01:31

These Falcon-9 components have a stage inert weight fraction in the vicinity of 5%. With 9 engines, that leaves very little weight for the tankage, actually. So the stage is a very fragile item structurally.

What they learned from the ocean landing attempts so far is two-fold: (1) a need for redundant attitude control during powered descent in the atmosphere, and (2) a need for a hard surface upon which to land. That last comes from the very soft touchdowns in the water, that they've already pulled off while retro-thrusting. The tankage broke up and sank on impact when it flopped over on its side. Which also proves my point about structural fragility, and why parachute water landings and 5% inert fractions have no "solution space" available.

They added the grid fins to maintain stability during atmospheric descent, even in an engine-off condition. What they found is that engine restart was impossible if it tumbled. The pinpoint landing on a platform "solves" the flop-over breakup problem after touchdown, hopefully. If they can hit the target, it might work.

I'm impressed that they are already successfully using hypersonic/supersonic retro-propulsion, uncanted. Nobody else seems to have picked up that. I'm not sure yet how they're handling the entry heating, which should be in the vicinity of Mach 8 to 10 when it first hits air.

GW

GW Johnson · 2015-01-10 15:45:53

I see in today's news that Falcon-9/Dragon launched successfully to ISS. The attempt to land and recover the 1st stage was only partially successful. They actually did hit the recovery barge, but they crashed hard upon it, near as I can tell. Still, they hit the target at all, that's significant in and of itself.

GW

Impaler · 2015-01-10 15:55:51

Can't wait for the vids, if you find some link them here, I'll do the same.

I'm not surprised they had an issue, they had always said the chance of success was small, just getting on the Barge is a partial success and they now have some hardware too do a inspection on (or do they have scrap metal?).

Found a vid:

https://www.youtube.com/watch?v=p7x-SumbynI#t=59

Last edited by Impaler (2015-01-10 16:13:59)

louis · 2015-01-10 19:44:59

GW Johnson wrote:

I see in today's news that Falcon-9/Dragon launched successfully to ISS. The attempt to land and recover the 1st stage was only partially successful. They actually did hit the recovery barge, but they crashed hard upon it, near as I can tell. Still, they hit the target at all, that's significant in and of itself.
GW

How does the barge work? Virtually any sea conditions will involve some pitch and roll. I'm assuming they must have some sort of gyro system on board that attempts to compensate and create a stable surface? Or maybe it has very strong magnets to hold the legs as they touch down? But that seems unlikely.

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