Ooops.

Faster, cheaper, better! This is called 'Lean Development", but I call it "Dreaming On". Unfortunately every MBA twit with his hand on the purse strings believes it's a workable proposition and is superior to doing things the Right Way.

One item making the rounds on the news in the past few days is the computer (well, there's 2 of them) on board Curiosity - basically a relic of the early 1990s, the computer cost about $200K back then and yet as I say that's not a ripoff - it reflects the volume of the product and the engineering and testing that went into it. It reminds me of the "nanosat" people (not all of them) who like to claim science payloads are too expensive and too big and you can somehow do everything with a piece of space junk. I believe nanosats have their uses, but it's far less than what many nanosat people like to believe.

When I saw the "methane + liquid O2" I thought "oh no, you have a relatively low density fuel which can create a hell of a lot of heat and less thrust" - good luck with that. I'm still a fan of motors based on the toxic and sometimes teratogenic hydrazine derivatives. I'm sure they'll get the engines working and the gizmo to stabilize eventually (at what cost compared to the not-lean development), but will it really be a sensible craft to use? We'll see.

I'm not sure what the point of using a "green" fuel on an extraplanetary lander is. I'm glad that accident didn't burn a bunch of hydrazine into my breathing air, but it's still a pretty insignificant amount compared to the hydrocarbons from burning gasoline everywhere. Are they planning on filling an Atlas rocket with this stuff?

Liquid methane is a lot easier to store than liquid hydrogen.

The major motivation for using methane is for utilization of in situ resources. Methane would be easier to make and store on Mars than would hydrogen. It doesn't give you quite as much thrust per unit mass as does H2/O2, but it is 3x denser, requiring smaller tanks. If you have to bring your tanks from Earth, that is a big deal.

Some of the scenarios are that you put a plant on Mars to make fuel, and have a fully refueled return craft in place before you launch a manned mission. If you are going to do that, the efficiency of CH4 as a fuel isn't that critical but the storage properties are.

Rovers on Mars are very nice, but having something that could fly hundreds of miles and refuel itself while the science package does its thing would be a nice capability to have prior to a sample return mission.

Hi deadalus2u:

The problem with the idea about the science package refueling itself is, where does the C and H2 come from? So Mars has an atmosphere that's ~95% CO2 - to produce methane we'd need to do something like bring in some bacteria that convert CO2 + H2O into CH4 + O2 and we have to keep that bacteria alive. I guess H2O can be condensed from the Martian atmosphere; come to think of it, we'd also need to compress and condense CO2 from the atmosphere to introduce it to the fuel plant in the quantities needed. I'd imagine CH4 would also be created in quantities that would require condensation from the air. I'm already imagining some fairly complex plant equipment .

Anyway, I'd be more interested in seeing a viable methane plant than in seeing a methane rocket motor. I'm confident the rocket motor can be built - I'd want to see if the refueling proposal could work because it would be one of the highest risk items in the project.

Faster, better, cheaper was mostly a success. The main problem IMO was in focusing too much on the "faster".
Lean engineering is just good engineering, but I'm not 100% on what is meant by "lean development". Smaller development teams are generally good thing (to a point), but fewer prototype cycles is certainly not a good thing (generally speaking). The use of off-the-shelf items can be both good and bad, but one certainly can't just trust them to conform to the specs they claim... so using OTS components requires more prototyping and testing.

Countdown is now 5-4-3-2-Zero? Drop a digit and save money?

Why is NASA testing a lander close to an array of what looks like LPG storage tanks?

On a more frivolous note: Under the foreground tripod (with an antenna array?) is a folding chair. Is that for the on-site observer?

MS, there is plenty of ice in the near surface. Methane can be made from CO2 and H2 and H2 can be made electrolytically from water.

https://en.wikipedia.org/wiki/Sabatier_reaction

The methane production is easier than the rocket science. How much CH4 would be needed depends on how efficient the rocket using CH4 is.

Liquid CH4 and liquid O2 are miscible and at a stoichiometric ratio they form an exceedingly powerful explosive (many times more powerful than TNT).

Throttling, turning off and especially turning back on are issues that launches from Earth don't usually face. Usual practice for fuel pumps is to use turbopumps run by sub-stoichiometric combustion that discharges into the combustion chamber. H2/O2 is easier to ignite and there are catalysts that will do so. CH4/O2 is more difficult and more dangerous (liquid H2 and O2 are at very different temperatures and don't mix as liquids). It isn't clear how stable combustion would be with liquid CH4 and O2 at temperatures that the turbopumps could survive. Stability at small scale might be quite tricky.

It is doubtful that they will be able to get enough helium on Mars to pressurize the tanks. H2 could be used to pressurize the CH4 tank, but not the O2 tank.

Ah, OK - so the plant wouldn't require any bioreactors - that's much better. I'd like to see the design for the compressors and refrigerators that operate in a Martian environment.

So the CH4 makes more sense to me now. The failure of this test doesn't bother me though; just think of all of von Braun's catastrophes or Goddard's long list of failures. If I were there I'd go "oh crap, but hey - it did get off the ground and what a show!"