New Mars Forums

I once offered to go up and scrub toilets on JP Aerospace's first full scale manned aerostatic platform.  They haven't responded yet, but I have high hopes.   8)

HELL YEAH!

I mean, er...  :oops:  Ahem...

I had not meant to imply that they were running out of money and time for launches, only for testing.

OK, ftlwright wins. 

The fix is relatively simple, and I didn't see anything in that release about how SpaceX intends to call it quits before their next shot.  I predict we'll see a successful launch within 14 months.

A slow loss of system pressure would create a gradually worsening loss of control, in which the stage could straighten up and fly right at first, even with a major upset like this collision, but later spin out of control under perfectly normal operating conditions.  That sounds completely consistent with what's shown in the video clip that SpaceX released, except one thing:

Who is David Palmer that he'd have access to the necessary telemetry to confirm this?  The video shows nothing one way or the other.

Musk made the claim a year or so ago that SpaceX expected failures and had sensibly budgeted for several of them.  I suspect that SpaceX is right where its investors expect it to be as far as destructive testing.  Projecting based on the previous two attempts, I estimate they'll be ready to fly again in 8 to 12 months - which, BTW, is surprisingly rapid turnover for a construction project of comparable complexity, and has been twice demonstrated by SpaceX. 

Unless Musk comes out and says they're going to fold, I see no reason to expect SpaceX to abandon their test plan before the next flight.

As for whether or not the fix to one particular problem is simple, who is to say?  For example, they got the camera to work right this time.  Who knows what might work next time.     

Overall system reliability of the Falcon prototype is not looking good at this point, but we're looking at a series of successively refined prototypes.  Observed performance of this system should still be varying on a curve at this point.  What we saw is what we should expect to see in this type of testing program - still failure, but failing after progressively better and better performance.  And it's what SpaceX has said they expect for the past four years.  The real death knoll of SpaceX will be to have precisely the same thing go wrong twice, with no corresponding improvement in performance.

There was clearly contact between the first stage and the second stage engine bell, with the second stage nozzle being nudged to one side.  And the video does not show any loss of roll control - the end shows what appears to be the beginnings of a spin, but it's all pitch and yaw ("Coning").  SpaceX's denial lacks credibility on those points.  However, it's also equally clear that the engine ignites as expected and the vehicle recovers after separation, suggesting that there was no irrecoverable damage to the gimbal.  The impact wasn't enough to knock those titanium spacers off, either, in spite of the fact that they appear to stick out about a couple of centimeters from the outer edge of the nozzle.

The trouble appears to set in at about the time the nozzle is starting to glow good and red.  At that kind of temperature, thermal expansion would create stresses in the engine just as great as or greater than anything it would have seen being brushed by the first stage.  Damage could have occured while the nozzle was being pushed around, but it did not cause the conveniently immediate failure that we would need to make a diagnosis based solely on this video.  There was no visible breakage, leakage or outgasing, and the engine functioned for a minute and a half with no sign of trouble.

This collision was minor and incidental.  I think the problem lies elsewhere.

Too bad: a few extra spacers would have been a quick and simple fix.

The manufacturer's brochure you linked to doesn't cover their performance under a concentrator, but being rated at 28% efficiency per ISO standards (NOT just under laboratory conditions) is nothing to sneeze at.

It looks like it's time to start revising some of our calculations upward from 10% (for silicone homojunction cells).

That's nice.  And when's the next one?

Yes.  The US Department of Housing and Urban Development successfully implemented US $15 billion in new programs, including the ongoing relocation from the New Orleans area and what has of necessity become a relatively effective nationwide effort to assist homeless families.  And Venezualan President Hugo Chavez implemented a very popular US $1 million heating fuel charity here in the States via Citgo, Inc. 

President Bush and his administration have been able to generate amazing levels of popular support for all of these new programs.

I would suggest you surf through the mission websites for each of the various landers which have reached the Martian surface.

For example, The Mars Pathfinder Probe team put together a very good website, which includes meteorological data from the probe's month long stay.

If you want temperature data taken over entire martian years, try NASA's Planetary Data System, where you can download instrument data sets from the various probes.

Ooooh!  I like that!  The prospect of manufacturing oxygen from the Martian atmosphere with only power input could save up to 0.9 kg/day per crewman.  If you can get the mass of these cells + power supply under 300 kg per crewman (entirely possible), it becomes a viable alternative to bringing all of the oxygen along for a surface stay of one year or more.  We'll want to strongly consider this completely aside from bobwd40's project.

The only consideration I have is: I can't find any successful demonstrations of this technology for CO2 scrubbing at the low concentrations expected inside the crew cabin.  If it could work with CO2 partial pressures that low, it wouldn't necessarily require a compressor to produce oxygen from the Martian Atmosphere - it could just work at ambient pressure.  But I find no indication that this is possible. 

This is still a fantastically promising technology.  I just don't know if it's going to take all of the Lithium Hydroxide off of the ship.

Dick's suggestion of using plants to produce oxygen is a viable alternative.  While it's true that this consumes water to produce oxygen, the mass efficiency is still higher than the use of disposable lithium hydroxide rebreather cartridges. 

There is another also alternative - recycle the cartridge vanes.  The half used lithium hydroxide vanes can be removed from the cartridge, baked in a kiln or steamed in a boiler at about 900 decrees celsius to reduce them back to Lithium oxide, then soaked with water to recharge them by generating fresh lithium hydroxide.  The process generates additional water, which can be reclaimed, and carbon dioxide, which can be dumped or otherwise treated in its pure form.  The vanes can't last indefinitely under this abuse, but you won't need six tons of them to replace the ones that crack beyond repair.  With an assumed loss rate of 10%, you could probably get the job done with 500 kg of rebreather cartridge vanes.  The kiln or boiler and requisite power supply necessary for this recycling operation won't weigh six tons, either - I've seen a suitable tube kiln that didn't weigh 6 kilos and only ate 2 kilowatts. 

You could easily fit the scrubber and entire recycling operation - power supply, plumbing, and all - into less than 1000 kg, 500 kg of which is consumables and 450 kg is power supply.

For an even lower mass alternative, you can powder the broken plates and recast them using the same kiln, at which point your 500 kg of consumables drops to 50 kg.  Unfortunately, this final reduction reflects on the robustness of the mission - kilns and presses can break, too, and all this firing and recasting (two full cartridges per day, by your count) takes time, during which backup cartridges must be constantly ready and available in rotation.  And there's no real experience to draw on for powder casting operations in zero-g if you lose gravity during the transit.  That's a lot of sugar for a dime.

So, while you could probably squeeze it down to about 500 kg, you should probably figure on about 1 ton for a system based on lithium hydroxide CO2 scrubbers, recycled using a kiln.