totm nov 2023 SpaceX Discussion Thread

[cubinator]

I almost feel like, with the level of technology available today, it would be feasible for some random dude like me to design, acquire funding for, build and fly a small Moon lander/rover and control it from my desktop PC...

[Xd the great]

2 minutes ago, cubinator said:

I almost feel like, with the level of technology available today, it would be feasible for some random dude like me to design, acquire funding for, build and fly a small Moon lander/rover and control it from my desktop PC...

Meh, they flew the shuttle with five computers each with less than 10MB of RAM. You can fly a dragon with a tab for sure.

[sevenperforce]

15 minutes ago, cubinator said:

I almost feel like, with the level of technology available today, it would be feasible for some random dude like me to design, acquire funding for, build and fly a small Moon lander/rover and control it from my desktop PC...

I underlined the difficult bit.

[sevenperforce]

On Pluto...

If you want to do a Pluto mission, just wait until BFR is flying. Build a massive 30-tonne Pluto science robot spaceship with an orbiter, a lander, and a sample return capsule. Send up a BFS tanker and refuel it in LEO with two additional launches. Mate your Pluto spaceship to a 110-tonne hydrolox Earth Departure Stage (Vacuum New Shepard or the like) and shove the whole affair into a cargo BFS. 

BFS launches to LEO, rendezvouses with the tanker, refuels, and burns to Earth escape. Open the clamshell, release the payload, and then turn around and burn slightly so the BFS can re-enter after a single eccentric orbit. The hydrolox stage burns the rest of the way to Pluto intercept, no Jupiter flyby or ion kick stage necessary.

[Elthy]

Dont forget that to reach Pluto in a decent time (<<100 years) you cant do a simple hohmann transfer. New Horizons took nine years to Pluto and passed it with 14.5km/s, which would need to be canceled out in case you want to reach orbit of even the surface. This isnt easily achievable with current technology...

[kerbiloid]

7 minutes ago, Elthy said:

Dont forget that to reach Pluto in a decent time (<<100 years) you cant do a simple hohmann transfer.

Let's be optimist. Pluto hohmanning can take just ~45.6 years according to a book.
So, we have 91.2 years for transfer and at least 8 years to stay there.

[sevenperforce]

11 minutes ago, Elthy said:

Dont forget that to reach Pluto in a decent time (<<100 years) you cant do a simple hohmann transfer. New Horizons took nine years to Pluto and passed it with 14.5km/s, which would need to be canceled out in case you want to reach orbit of even the surface. This isnt easily achievable with current technology...

Ah, very good point. 

I wonder if you could use an excess-hyperbolic Type I transfer out of LEO to Neptune, and then use a Neptune flyby to lower velocity to reach Pluto with lower excess hyperbolic velocity. Might lower intercept speed to something that a big hydrazine (or even hypergolic biprop) tank could handle.

[tater]

 

[cubinator]

2 hours ago, sevenperforce said:

I underlined the difficult bit.

Definitely. You'd have to know all the right people...

It'd be interesting to try something like this, but have, say, 100 miniature rovers launched to different parts of the Moon, and a Starlink constellation in orbit, and set up a computer program that lets people drive a rover around for, say, an hour, and flag interesting things for science and enjoyment, taking pictures and whatnot. You would want the rovers to have some autonomy, and be able to decide for themselves whether a given command is safe to perform. ("No, human, I won't go into that rocky hole because I think I might get stuck in there." or "Instead of going straight over that big rock, I'll go around it.") With 100 rovers, 2400 people could drive each day for an hour. That's about 70000 people in a month. With 30 minute session lengths instead, you could get through ~140000-148000 people. While it's likely that millions of requests would clog up the waitlists, a lot of people would still get to drive a Moon rover from their own computer, and potentially advance Moon science significantly.

Disclaimer: This would be something to do with something like BFR, once it is active and super cost-effective. I don't see it happening that soon, but maybe eventually. This is completely speculative.

[sevenperforce]

7 minutes ago, cubinator said:

Definitely. You'd have to know all the right people...

It'd be interesting to try something like this, but have, say, 100 miniature rovers launched to different parts of the Moon, and a Starlink constellation in orbit, and set up a computer program that lets people drive a rover around for, say, an hour, and flag interesting things for science and enjoyment, taking pictures and whatnot. You would want the rovers to have some autonomy, and be able to decide for themselves whether a given command is safe to perform. ("No, human, I won't go into that rocky hole because I think I might get stuck in there." or "Instead of going straight over that big rock, I'll go around it.") With 100 rovers, 2400 people could drive each day for an hour. That's about 70000 people in a month. With 30 minute session lengths instead, you could get through ~140000-148000 people. While it's likely that millions of requests would clog up the waitlists, a lot of people would still get to drive a Moon rover from their own computer, and potentially advance Moon science significantly.

Disclaimer: This would be something to do with something like BFR, once it is active and super cost-effective. I don't see it happening that soon, but maybe eventually. This is completely speculative.

And just like that you would have 100 male organs drawn on the surface of the moon.

Rover McRoverFace all over again.

Edited August 17, 2018 by sevenperforce
Dagnabit filter

[Ultimate Steve]

22 minutes ago, sevenperforce said:

And just like that you would have 100 male organs drawn on the surface of the moon.

Rover McRoverFace all over again.

You could make a line in the computer to say "hey, this maneuver spells ___ or looks like ___, let's not do this" because if you can program the rovers to not go into holes you can probably program them for 2d path recognition.

[sevenperforce]

30 minutes ago, cubinator said:

With 100 rovers, 2400 people could drive each day for an hour. That's about 70000 people in a month. With 30 minute session lengths instead, you could get through ~140000-148000 people. While it's likely that millions of requests would clog up the waitlists, a lot of people would still get to drive a Moon rover from their own computer, and potentially advance Moon science significantly.

Driving a rover from your computer is tricky with the 3-second lightspeed delay. Better to have a bunch of tiny autonomous rovers doing a Google Street View thing, and then you could have human people navigating the existing data and flagging stuff that way.

[cubinator]

25 minutes ago, sevenperforce said:

Driving a rover from your computer is tricky with the 3-second lightspeed delay. Better to have a bunch of tiny autonomous rovers doing a Google Street View thing, and then you could have human people navigating the existing data and flagging stuff that way.

I think if you showed a "virtual rover" in the view on your computer that reacts instantly and shows where the rover will be in 3 seconds, it would actually not be too bad. The Street View method is a good idea, too.

[StrandedonEarth]

1 hour ago, cubinator said:

Definitely. You'd have to know all the right people...

It'd be interesting to try something like this, but have, say, 100 miniature rovers launched to different parts of the Moon, and a Starlink constellation in orbit, and set up a computer program that lets people drive a rover around for, say, an hour, and flag interesting things for science and enjoyment, taking pictures and whatnot. You would want the rovers to have some autonomy, and be able to decide for themselves whether a given command is safe to perform. ("No, human, I won't go into that rocky hole because I think I might get stuck in there." or "Instead of going straight over that big rock, I'll go around it.") With 100 rovers, 2400 people could drive each day for an hour. That's about 70000 people in a month. With 30 minute session lengths instead, you could get through ~140000-148000 people. While it's likely that millions of requests would clog up the waitlists, a lot of people would still get to drive a Moon rover from their own computer, and potentially advance Moon science significantly.

Disclaimer: This would be something to do with something like BFR, once it is active and super cost-effective. I don't see it happening that soon, but maybe eventually. This is completely speculative.

I proposed something similar in this forum a few years ago. You’re forgetting the most important thing that will cut down the wait list: revenue! Sell time on the rovers!

My I dea was to have a Lunar Racing League with reasonably fast, more durable rovers. And yes, dealing with the time lag would be part of the challenge. OTOH, this could be done with just a computer simulation, with simulator champions allowed to drive the real ones. 

There’s more to the idea than that, but that’s the core of it. The key is to sell time on these units!

[CatastrophicFailure]

1 hour ago, sevenperforce said:

Driving a rover from your computer is tricky with the 3-second lightspeed delay. Better to have a bunch of tiny autonomous rovers doing a Google Street View thing, and then you could have human people navigating the existing data and flagging stuff that way.

Keep in mind, someone still had to drive all those Google vans to get those street view pics...

Interesting idea overall, I remember there was once a plan to do something similar with just a single rover, but that was years ago and prolly fell thru. With dozens or hundreds, I wonder if it might do more harm than good. On the one hand, thousands of amateur eyes are likely better than a few “real scientist” eyes for a lot of stuff, but some features in the regolith that only a geologist could spot might get ruined by rover tracks.

Also, all those organs emblazed on the moon for eternity...  Imagine future alien archaeologists trying to figure that one out. 

[NSEP]

4 hours ago, sevenperforce said:A rover might be asking for a bit much.

Even then a rover would be really, really pushing it.

Going into orbit and landing on the surface is going to be a challenge with such a limited payload mass, sure, but if you can land, you can without a doubt drop a rover. When talking about a rover im talking less Curiosity and more Sojouner.

You can very easily make a rover less than 15kg. Doesn't need its own power source. Just attach it to cable and the power would be supplied by its host lander. Sure, it probably can't go explore the entire planet like curiosity but it can do something.

3 hours ago, sevenperforce said:

On Pluto...

If you want to do a Pluto mission, just wait until BFR is flying. Build a massive 30-tonne Pluto science robot spaceship with an orbiter, a lander, and a sample return capsule. Send up a BFS tanker and refuel it in LEO with two additional launches. Mate your Pluto spaceship to a 110-tonne hydrolox Earth Departure Stage (Vacuum New Shepard or the like) and shove the whole affair into a cargo BFS. 

BFS launches to LEO, rendezvouses with the tanker, refuels, and burns to Earth escape. Open the clamshell, release the payload, and then turn around and burn slightly so the BFS can re-enter after a single eccentric orbit. The hydrolox stage burns the rest of the way to Pluto intercept, no Jupiter flyby or ion kick stage necessary.

Yes.

Yes.

[CatastrophicFailure]

On the Pluto thing (SQUERL!)... what’s the lightest possible nuclear-electric system that could work with current tech? Could they get such a thing down below 3500kg? Gotta be able to squeeze 15 or 20km/s out of something like that for an orbiter...

[Ultimate Steve]

1 minute ago, CatastrophicFailure said:

On the Pluto thing (SQUERL!)... what’s the lightest possible nuclear-electric system that could work with current tech? Could they get such a thing down below 3500kg? Gotta be able to squeeze 15 or 20km/s out of something like that for an orbiter...

 

The Soviet TOPAZ-I nuclear reactor was 320kg and the TOPAZ-II reactor was ~1000kg. TOPAZ-I could make 5KW of power for 3-5 years. This technology is decades old, if we can't make it better by now we're not doing something right. 

[sevenperforce]

28 minutes ago, CatastrophicFailure said:

On the Pluto thing (SQUERL!)... what’s the lightest possible nuclear-electric system that could work with current tech? Could they get such a thing down below 3500kg? Gotta be able to squeeze 15 or 20km/s out of something like that for an orbiter...

Concern would probably be getting the reactor to sit dormant for a decade then pop online autonomously and start working.

[DAL59]

4 hours ago, Elthy said:

Dont forget that to reach Pluto in a decent time (<<100 years) you cant do a simple hohmann transfer. New Horizons took nine years to Pluto and passed it with 14.5km/s, which would need to be canceled out in case you want to reach orbit of even the surface. This isnt easily achievable with current technology...

You could with an ion engine, but how would you power it so far from the sun?  Most RTGs don't produce enough to run an ion engine.

[Ultimate Steve]

2 minutes ago, DAL59 said:

You could with an ion engine, but how would you power it so far from the sun?  Most RTGs don't produce enough to run an ion engine.

Power the ion engine with a nuclear reactor?

[DAL59]

5 hours ago, cubinator said:

I almost feel like, with the level of technology available today, it would be feasible for some random dude like me to design, acquire funding for, build and fly a small Moon lander/rover and control it from my desktop PC...

Given that many colleges have cubesat building, its not that inconceivable.  The cost to launch an Electron rocket is "only" 6 million.  

Just now, Ultimate Steve said:

Power the ion engine with a nuclear reactor?

Good luck getting approval for that

[Ultimate Steve]

Just now, DAL59 said:

Good luck getting approval for that

It's not impossible. There have already been several nuclear reactors in orbit before (mostly Soviet). And those things have only gotten safer since then (if public approval has gone down).

[HebaruSan]

1 hour ago, CatastrophicFailure said:

Also, all those organs emblazed on the moon for eternity...  Imagine future alien archaeologists trying to figure that one out. 

Archaeologists? Bet on "religious symbolism."

[sevenperforce]

41 minutes ago, HebaruSan said:

Archaeologists? Bet on "religious symbolism."

Spoiler