I used to work at JPL, and I was there when the sky-crane (the system currently used to land rovers on Mars) was first proposed back in the late 90s. I remember thinking to myself, "That is the craziest idea I have ever heard, there is no way that could possibly work." But it did.
Never bet against NASA engineers. Sure, they have the odd high-profile screwup, but on the whole they are shockingly competent.
Do you know if there is any test footage of that anywhere? That's, to me anyway, the second most amazing thing about the sky crane...that I can't find a single frame of it in operation on earth.
Sure the final mission configuration isn't exactly what they would test, but the differences in the sky crane maneuver on Mars and Earth would be relatively easy to factor in (ok, that might be an exaggeration, but its doable). There is a ton of control development that would need to be sorted out so they knew how to integrate it all. For example, I had heard that the primary indicator that the rover had touched down simply watching the throttle on the closed loop flight control system. When it throttled down it meant the rockets were no longer suspending the weight of the rover. If true, I would think you would want to test that quite a bit...
FWIW they tested missile defense 'kill vehicles' on the ground and they will operate at or near orbital velocity in space. The main 'hover thruster' would likely be completely unnecessary in a live exercise:
> The thing could simply blow up on the launch pad, for goodness sake!
exactly, I’ve wondered why they don’t build e.g. 2 or 3 of them in tandem since it’d likely be cheaper/easier to do up front vs after the fact if things went wrong. They would then have the additional telescopes if things went right, offering even greater access.
You're correct - building constellations is definitely much cheaper.
For an observational/capability platform such as for DoD or NOAA, making a large number in a series makes sense. For a research platform (NASA/NSF) that same idea doesn't apply, since science objectives dominate the discussion.
With Mars landers, they do build two of them. When they have an issue with the one on Mars, they break out the one here on Earth and start debugging. When they have a solution that works, then they know what to do with the one on Mars.
I don't know if that would work on telescopes, though - I suspect that the copy wouldn't have the full optics installed.
I don't know why, but I've had this gut-wrenching feeling for a couple of years now that Something Terrible is going to happen to this before it gets into position at L2.
I really hope not, obviously, but this seems like an All Your Eggs In One Basket lesson in the making.
We need to commodify this tech, make them somewhat disposable, and sent oodles of them up on Starships.
Using 3 COTS (Commercial Off The Shelf) components with 90% reliability can ensure 99.9% redundancy instead of having a Unique very reliable and even costlier 99.9% custom component can really lower costs.
But it can happen only if mass is not a constraint.
The Perseverance Mars rover cost $2.4 billion, which works out to a few thousand salaries for just under a decade. Thousands of people are needed to build this rover because landing stuff on Mars is so hard that subsystem masses must be tracked to a tenth of a gram, on a system that weighs a tonne. The whole thing is meticulously handcrafted from custom silicon, PCBs, titanium tubes, motors, cameras, and other awe-inspiring instruments. Starship will be able to land 100 of them per flight. Now what? How can NASA feed a team that makes one feather light rover per decade for a billion dollars if the demand just jumped by a factor of a thousand and the unit cost fell by the same amount? Set up a production line? Work out how to make them with a team of ten? Build one every two weeks?
They should put that team to work on next-generation tech, the stuff that's not yet a commodity. They can start working on habitat construction materials and hardware, for instance.
Although it is interesting to consider that we've put a lot of expense into optimizing payloads that, in retrospect, would have been smarter to put into better launch vehicles. SpaceX probably isn't going to spend $2 billion developing Starship (even if Boeing would have.)
IIRC, SpaceX is getting $2.89B from NASA for the Artemis lander, which proposal is based on Starship. Although, the GAO put that on hold recently, after complaints from BlueOrigin and Dynetics. Hardly surprising, I guess.
I think this part of the problem though. We don't believe we can really do anything at this point so we have turned everything into a stochastic process with multiple draws needed and it gives everyone an out when things don't work.
"Oops, JWST blew up, guess we just got unlucky with that single draw from the urn. Shouldn't have put all our eggs in one basket. "
Just do it. No more urn thinking. Just launch , get in orbit and blow our minds with the data that is sent back. I don't want to hear about anything less than that.
