Purdue Students Building Moon Lander Rocket

tekgoblin sends words that a team of students at Purdue University are working on a project to build a rocket engine that could be used on a future Moon lander. Quoting: "Graduate students Thomas Feldman and Andrew Rettenmaier are part of a team developing a thrust chamber for NASA's Project Morpheus, which includes research to develop new technologies for future trips to the moon, Mars or asteroids. The rocket must meet stringent design and performance specifications related to factors including efficiency, size and weight limits, thrust and the ability to dynamically throttle the rocket from 1,300-4,200 pounds of thrust, Feldman said. ... A development test chamber has been designed and is ready for testing. This heavily instrumented chamber is far bulkier than the eventual flight chamber, and data from upcoming tests will be used to refine the flight engine's design."

Comments

ooh yeah

[tekgoblin]

Boiler UP!

Nerd quotient

[currently_awake]

Nothing like building space craft. And the USA has plenty of launch options for stuff that doesn't come back in one piece.

Re:Such a waste

[wsxyz]

They seem to be learning about intelligently designing a rocket motor, which is obviously unconstitutional, and can't possibly work anyway.
I don't fly want to fly in a rocket designed any other way than by natural selection.

Pfft

[sir_eccles]

It would be easier to just use a solid rocket booster from ATK.

Re:Pfft

[gizmo_mathboy]

Because you can vary the thrust on a solid rocket booster, not.

The lander probably needs variable thrust. Solids won't be very useful for that.

Re:Pfft

[tragedy]

The GP is, I believe, making a joke about the corrupt political process through which most NASA parts are sourced (by congressmen who know nothing about rocketry) and which often becomes an overriding factor in their design. Basically, congress tells NASA that they will use engines from _this_ manufacturer, in _this_ district, then NASA has to design the rest of the mission around what that manufacturer can actually provide them. ATK bought the Thiokol rocket division (after a few intermediate splits and mergers), who were the mandated provider of solid rocket boosters for the shuttle program. It's actually quite possible that, had they not been mandated, solid rocket boosters might not have even been used for the shuttle. In any case, the location of the manufacture of the rockets required that they be shipped in sections and then re-assembled with some o-rings between the sections. The o-rings were known to wear nearly all the way through on all shuttle launches up until Challenger blew up because one wore all the way through.

Official reports did put most of the blame on Morton-Thiokol for the Challenger disaster. There's a reasonably convincing case that, if NASA had been given a choice in providers, the disaster would have never happened. Of course, it would be unfair not to mention that, even if produced locally, or somewhere that the rockets could be delivered by sea, completing the entire solid rocket booster in one pour would be a challenge, so it might have needed to be segmented anyway. Of course, they might not have gone with solid boosters...

Re:Pfft

[hackertourist]

The boosters for Ariane 5 (a bit smaller than the Shuttle SRB, but close enough) are shipped to French Guyana empty. ESA/Arianespace have built a casting facility on site.

Re:Pfft

[tragedy]

I did read the findings of the commission , although it's been a long time. Would "came apart like wet tissue paper" have been more accurate? They were extra-fragile in the Challenger case because they were cold, but even when not cold, they apparently made it a significant fraction of the way towards total failure on many previous uses. I may have misremembered just how severe the previous failures were. Oh, and I certainly know who Richard Feynman was. The fact that the O-rings were already a known problem for about a decade before Challenger blew up is one of the things that lead him and the commission to call Challenger "an accident rooted in history".

The commission found NASA and Morton-Thiokol to blame both for not stopping the launch despite a known unsafe condition and for not moving to correct the flaw with the O-Rings in the first place. In any case, although the story of a manager telling an engineer to "take off [his] engineering hat and put on [his] management hat" may be apocryphal, clearly the immediate cause of the Challenger disaster was management (Morton-Thiokol's management declared the situation safe under pressure from NASA management) over-riding sensible engineering concerns.

I did say that it was probably unfair to say that the location of the manufacture of the boosters was the only reason they had to be made in sections and that doing it in one pour would be a challenge. As I understand it the challenges are from too many bubbles ending up cemented in the mixture in a long pour and from the static issue you mentioned. Also possibly because they might have more chance of cracking during shipping and raising if made as one long piece. None of those challenges seems insurmountable. However, since they had to ship from Utah, they had to make them in sections anyway, so there was no reason to try. What you're saying doesn't seem to disagree with what I'm saying at all, unless you're trying to say that making it as one piece is completely impossible, which I don't believe to be the case. Still, they might have made them in sections wherever they made them, so I guess it's a tenuous case whether location of manufacture caused the Challenger disaster.

Still, there can be little doubt that politics has a lot to do with who NASA uses as suppliers and what state they're located in. Politics also played a very obvious role in the management decisions that doomed the Challenger crew. Politics and management played some role in the Columbia disaster as well. Mainly in quashing attempts to assess the damage and research possible ways to save the astronauts. In the Columbia case, of course, there was probably nothing that could have actually saved them at that point.

As for throttling solid rockets, I didn't say anything about that. That was from a previous poster. In any case, is throttling feasible on small solid rockets like what you'd need on a lander? Not that the original post about using solid rockets from ATK on the lander was serious. Although I suppose a hybrid system with invariable thrust rockets combined with variable ones could be used for a lander.

Re:Pfft

[tragedy]

Ah. Can I assume that they are completed in one pour and conclude that completing a large solid rocket booster in one pour is therefore not impossible?

Re:Pfft

[hackertourist]

I assumed that they'd be cast in a single pour, but apparently not: booster manufacturing process

Re:Pfft

[tragedy]

Hmm, diagram on that page is very unsatisfactory. Hard to tell if they do use interlocking segments with an o-ring in their design or not. If you actually pour in place, I suppose you could probably do away with the o-ring design by just leaving enough clear space that you can weld the inner sections together safely, then pour directly on top of the previously solidified propellant rather than having to do the careful alignment and rely on relatively flimsy o-rings. Maybe it just doesn't matter if hot gases leak out between segments. The reason it was a problem with the shuttle is because the escaping gases burned their way into the main liquid fueled tank. If your solid fuel rocket is just a single column and not attached to anything, it may not matter.

Re:Such a waste

[Roachie]

Yea, once dogs evolve enough to teach aerospace engineering it is my hope that they will be the ones to put and end to crap like this.

Re:keep trying guys !

[gizmo_mathboy]

The Purdue folks just built the engine. They didn't build the lander.

Re:Armadillo Aerospace

[gizmo_mathboy]

Compare the Lunar Lander from Apollo to the Armadillo craft to the Morpheus project.

There is only so many configurations where you have a centrally mounted engine and a bunch of spherical propellant tanks.

Not so much a knock off as that is what physics and mother nature dictates.

Re:Worked on Mars

[gizmo_mathboy]

Would you rather deal with 2 systems (variable thrust engine and an air bag deploy system) or just 1 system?

You would need an engine regardless, there is no atmosphere on the moon so you can use the Martian solution. You could use a parachute for the bulk of the descent and then have the air bag.

I wouldn't even dream of using an air bag for manned missions, no control of the impact at all.

With variable thrust you have controls systems to keep things stable and can vector out of the way like Neil did on Apollo 13.

An aircraft is not a spacecraft so "imagine controlling an aircraft without control surfaces" is a non sequitor. In fact, some aircraft can be partially controlled without flight surfaces (vectored thrust fighters that stand on their tails and use engine thrust to spin about, see Cobra maneuver.

No atmosphere, no control surfaces. All you are left with is thrusters and what little gravity there is.

Re:no, no, NO!

[sconeu]

So what *DOES* the future of the Turkish textile industry look like?

Re:Such a waste

[tragedy]

Rockets are made through intelligent design and _artificial_ selection. Rocket designs that explode during testing generally don't get to have unmodified offspring.

Re:Worked on Mars

[tragedy]

Square-Cube ratio. Or rather, sphere-radius to sphere volume ratio. Larger payloads are a lot harder to land with an airbag system than small ones like the Mars rovers. As the payload gets more massive, the size (and complexity) of the airbag you need to safely stop all of its kinetic energy increases more. That's why the up and coming Mars rover, which is the size of a compact car, is not going to be landed with an airbag system.

Hmm. That got me thinking, anyone have the numbers on the maximum speed an object can reach falling towards the moon? If it started say from the earth-moon Lagrange point with no relative momentum?

Re:Such a waste

[LifesABeach]

Given that the design is from Purdue, not Evansville, one hopes that when metric conversion is discussed, it isn't considered a religious subject,(SNAP! Purdue). But all inner university rivalry's aside; given that the name of the project is, "Morpheus"; I would hope that Purdue's students would anodize the engine red.

Re:Such a waste

[tragedy]

Given that the project name is Morpheus, I just hope they don't fall asleep while operating rockets.

Re:Worked on Mars

[mmontour]

Hmm. That got me thinking, anyone have the numbers on the maximum speed an object can reach falling towards the moon?

Same as the escape velocity, which Google says is 2.38 km/s.

Re:Such a waste

[LifesABeach]

I believe that if Purdue anodizes the engine blue, then I would hope that the crew wakes up in time.

Re:Worked on Mars

[tragedy]

Definitely pretty ouchy. I was just asking because of the whole airbag question. With no aerobraking, you have to have rocket boosters to land, or you have to have a passive landing system that can absorb a ridiculous amount. Just wasn't sure offhand what the best case scenario was for that ridiculous amount.

What's wrong with the Lunar Module descent engine?

[jwilso91]

TRW's lunar module descent engine was quite a piece of engineering. Turns out that the ability to throttle down to 10% of rated thrust is rather difficult to achieve in a biprop engine. The eventual design made some serious compromises to gain the throttleability that generations have enjoyed in lunar landing simulators - it could not run stably at all in the 65%-95% range.

I can understand wanting to reinvent the wheel for the sake of the inventing, but this was a particularly tough nut to crack and one (to my knowledge) not yet duplicated elsewhere. Note that the throttling specified for the Purdue effort is 3:1, considerably less challenging than the 10:1 available to the Apollo astronauts during landing.

Re:BS until I see some build standards roxy

[Coren22]

Woosh?