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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."
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.
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.
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?
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.
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.