Purple glistening plasma, you say? Orion plummets back to Earth NASA has released video images of its Orion spaceship as it re-entered Earth's atmosphere earlier this month. It shows the view that astronauts might eventually see if the US space agency's mission to send human beings to Mars in 2021 proves successful. On 5 December, Orion flew unmanned this time. In order to gather as much …
They talk about using this capsule for trips to Mars - presumaby it will be attached to a larger craft for them to live in during the voyage? It looks like there isn't room to swing a tribble. If the capsule is all the room they have they bold voyagers will have killed each other within 30 days.
In fact, why take the Orion capsule to Mars? Would it be too complicated to leave a simple landing capsule parked in Earth orbit and dock and transfer to it on return? Or would approach velocity be too much to allow for docking?
Probably simple and obvious answers, but I'm not a rocket scientist.
Rendezvous, while trivial (in the grand scheme of things) for probes, becomes life and death and time limited for Astronauts. So taking it all with you, has advantages. Proves/automated craft can "wait a day or two" if they miss something or should a part perform under spec.
(I assume, IANAA but do play KSP ;) )
If you need to slow down enough to enter orbit when you get back to Earth, you have to haul the fuel to do that with you to Mars and back. You also need extra fuel to accelerate that fuel out of Mars orbit to get back, and extra fuel to decelerate both those quantities of fuel into Mars orbit when you get there, and still more to accelerate all three lots of fuel out of Earth orbit and towards mars in the first place.
Much less mass requirement to take your re-entry vehicle along with you, not bother with getting into Earth orbit when you get back, and use a beefy heat shield to re-enter directly.
Getting from a Mars->Earth transfer orbit into Earth orbit would use loads of fuel, which you'll need to haul all the way to Mars and back; plus it's another complex manoeuvre in an already complex mission profile. (It's possible to reduce fuel requirements by aerobraking the entire vehicle in Earth's atmosphere --- that way you just need a small amount of fuel to circularise your orbit once you've been captured --- but that's even more hairy.)
Given that you're not going to be reusing the Mars transfer vehicle anyway (it'll be several years old and rather beaten up), you might as well just dump it in the atmosphere and land the crew in a capsule. That way no braking is required --- your transfer orbit just dives straight into the atmosphere.
"They talk about using this capsule for trips to Mars - presumaby it will be attached to a larger craft for them to live in during the voyage?"
Correct: http://en.wikipedia.org/wiki/Deep_Space_Habitat
"In fact, why take the Orion capsule to Mars? Would it be too complicated to leave a simple landing capsule parked in Earth orbit and dock and transfer to it on return?"
One factor is the complication of a rendezvous in space. All operations in the mission will need to consider that final, critical rendezvous to get the astronauts home, as opposed to always having the capsule along for the ride. There's also the matter that leaving your escape- and re-entry vessel somewhere other than that place on the map marked "you are here" increases risk. Having the Orion capsule along for the entire ride opens up options in most emergency situations (see: Apollo 13 and its handy LEM). When going to a destination where more than 50% of missions meet the Great Galactic Ghoul, emergency options are important.
"Or would approach velocity be too much to allow for docking?"
That's an issue in some scenarios, too. If the Mars missions make the Deep Space Hab expendable (due to design or emergency) then, contrary to the Dark Helmet Lesson, you don't need to slow down first. Having the capsule along for the ride means you can head straight for the high-G aerobraking without any froo-froo parking in LaGrange orbits, perigee braking burns to match the capsule's velocity, preliminary aerobraking maneuvers, and so on.
In short, leaving the capsule along would save fuel at the expense of additional headaches and ulcers for many other parts of a Mars mission.
after a bit i figured out the view was through the rear window
but why did they feel it necessary to splice on the two blurred sidebars and add the silly sound track, instead of silence or whatever noise was to be had inside?
perhaps they assume the audience is incapable of handling video in a 1:1-ish aspect ratio with no sound, but this sort of needless embellishment subtracts from the original, get ready for future nasa videos featuring sound in a vacuum
I recognise the heat shielding problems it would raise but I would love to see the footage from a 'down' view camera...
The view from the front-side plane of the heat-shield as the capsule skimmed through the atmosphere would be awesome, (right up until the glare from the plasma washed out the CCD's filters completely). And actually seeing the planet getting larger and closer as the machine falls through the atmosphere once it comes back under attitude control would make the zoom function on Google maps look totally pathetic.
I guess I'll just have to wait until someone can work out how to make transparent ceramic heat resistant tiles.
The video was nice, but I would like to know the results of all the tests they performed.
Radiation, shielded sufficiently or not?
Did the craft perform within specs?
Any issues that have been discovered that need to be addressed?
Cats, shielded sufficiently or not?
(one can assume so on that last point...otherwise you know one of those little buggers would have curled up right on the camera lens)
What a strange and ethereal video. Thank you.
I don't pretend to understand what's going on here, or even which way up things are, but then it's my birthday and I'm smashed on hash and brandy before breakfast. Which means I sympathise with that capsule; orbit's one thing, re-entry's a bitch.
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