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SpaceX Starship

Some interesting stuff coming up

Delta 4 heavy is officially gearing up for its final flight, sad times. This beast of a rocket and its RS-68 engines are incredible. The flight is currently scheduled for tomorrow afternoon, but weather is looking questionable.





The Event Horizon Telescope has observed the magnetic fields revolving around the black hole at the center of our Milky Way galaxy



SpaceX conducted a second static fire of S29, this time being one engine running off fuel from the header tank. Emulating the reignition they had to skip on the last flight, and want to complete on this upcoming flight. As far as the general public knows, this means S29 is done with testing and will probably be moved back to the production site for final touch up work while B11 goes through its test campaign



And a production diagram of the latest down in Starbase:

 
The final ULA Delta 4 Heavy launch is in 13 minutes if the weather holds out. Sounds like low percentage of go today though

ULA official live stream:



NSF live stream:



Everyday Astronaut:



 
Cool space story today - hoping an IBB resident rocket scientist can help me understand how this could work. As I understand it, an orbiting craft's speed is determined by its weight and altitude. For example, if you want a 10kg satellite to orbit at 400km altitude it has to go 7860 kmh. Any slower and it will fall into atmosphere and burn up, any faster and it will fling off into space. So how are they going to be able to match speed to refuel when the 2 craft don't weigh the same?

techcrunch.com

Orbit Fab unveils $30K port to refuel satellites | TechCrunch

Orbit Fab wants to build a network of gas stations in space.
techcrunch.com techcrunch.com


Orbit Fab unveils $30K port to refuel satellites​

Aria Alamalhodaei@breadfrom / 11:34 AM PDT•March 29, 2024

bit-satellite-equipped-with-a-RAFTI-refueling-port.jpg

Image Credits: Orbit Fab(opens in a new window)
Orbit Fab wants to build “gas stations” for satellites — which means it needs the gas cap, a mechanism for transferring propellant from an orbital tanker to the customer spacecraft. That docking mechanism, called RAFTI, is now flight-qualified and on the market. The price tag for each port? Just $30,000.
The Colorado-based startup (and former TechCrunch Disrupt Battlefield finalist) has been in operation since 2018, and its CEO and co-founder Daniel Faber has been working in the space industry for decades; he’s likely best known for heading up Deep Space Industries (DSI), a company that was targeting asteroid mining. The company, which was founded in 2012, was acquired by Bradford Space seven years later.
“If you want [to talk about] something that’s too early, that’s it,” he joked during a recent interview. As part of the company’s efforts to eventually build tech capable of prospecting a distant asteroid, DSI built satellite thrusters for orbital maneuvering. This work, and subsequent conversations with customers and colleagues, eventually led Faber to believe that the next big opportunity was in-space refueling.

Part of it is simple math: Colleagues and former customers told him that they could squeeze as much as $1 million in marginal revenue from satellite missions from an extra kilogram of propellant
 
Fuzzydog said:
Cool space story today - hoping an IBB resident rocket scientist can help me understand how this could work. As I understand it, an orbiting craft's speed is determined by its weight and altitude. For example, if you want a 10kg satellite to orbit at 400km altitude it has to go 7860 kmh. Any slower and it will fall into atmosphere and burn up, any faster and it will fling off into space. So how are they going to be able to match speed to refuel when the 2 craft don't weigh the same?
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Your orbit isn't based on your mass at all, for an orbit around Earth it's only a function of your velocity really and that determines what your orbit is.

There's an explanation here of how the math works out: 13.4 Satellite Orbits and Energy - University Physics Volume 1 | OpenStax

But the equation as they ultimately show is:

1712005579660.png


And G and ME are constants, so it's really just v = sqrt(1/r)

Two spacecraft meeting up isn't new, any time something goes to the space station they are doing the same thing. This is also why there are a fixed amount of locations for geostationary spacecraft since there is one velocity and one orbit that works for geo, so there is a finite number of positions to fit into there.



I didn't read the article, but refueling has become a popular idea in recent years with a number of places wanting to demonstrate it. The downside is, existing hardware on orbit isn't setup to be refueled. So you end up with a chicken or the egg scenario. You could send up spacecraft now that can be refueled, but it will be decades before they need it and they need to have a refueling system that matches whatever spacecraft is docking with them. Or you develop the refueling system first and get people to buy in to that configuration, but who is paying for that when the refueling spacecraft won't be needed for decades and that's assuming anyone puts that refueling interface on their spacecraft?

I think there's some spacecraft that maybe were forward thinking to make some kind of refueling port, but they would be extremely rare and that's a lot of added complexity and risk. There's also concepts for "space tugs" where you can't refuel the spacecraft but you could go and latch onto one and provide your own propulsion to boost it, which would work with existing hardware on orbit assuming there was a decent way to interface the orbiting spacecraft without screwing something up.
 
Fuzzydog said:
So how are they going to be able to match speed to refuel when the 2 craft don't weigh the same?
Click to expand...
The refuel vessel doesn't have to be in a stable orbit, it just has to pull alongside long enough for transfer. I would guess it can also use more thrusters than the satellite that's staying in orbit, since it's a temporary mission.
 
Man, that triple header that almost happened the other day (Bigun's links) would have been record setting by a long shot. SpaceX was on track to launch a F9 from all 3 active falcon 9 launch pads within under ~5 hours. Previously their record was 20 something hours IIRC. They got the two Florida launches off without a hitch, but the California launch didn't play nice.

Fuzzydog said:
Cool space story today - hoping an IBB resident rocket scientist can help me understand how this could work. As I understand it, an orbiting craft's speed is determined by its weight and altitude. For example, if you want a 10kg satellite to orbit at 400km altitude it has to go 7860 kmh. Any slower and it will fall into atmosphere and burn up, any faster and it will fling off into space. So how are they going to be able to match speed to refuel when the 2 craft don't weigh the same?
Click to expand...

That's a cool deal, I think satellite refueling will have a future. Although not quite as impactful as it would have been ~10 years ago, because as it's become cheaper to launch things, satellites have become cheaper too (meaning replacements are more attainable).

As far as the orbit question, weight actually isn't a factor. Just altitude and speed. At a certain desired altitude, the required speed for a circular orbit is dictated by the gravitational constant of 9.8m/s/s. Below that speed threshold, gravity wins and you gradually lose altitude. Exactly at that threshold, you fall in perpetuity but never get closer to the ground (perfect orbit), above that threshold the velocity beats gravity and your altitude increases.

Goes back to that old example, where in a complete vacuum a bowling ball and a feather fall at exactly the same rate. But the mass and surface area do come into play when the friction of air is involved. And even in most useful orbits today there are still trace amounts of air which causes craft to slow down over time so it's not technically "zero" effect, but for understanding orbits it's not necessary.

I'm too slow, these guys have it covered :laughing:

Bowling ball vs feather in a vacuum:



Orbit explained in 30 seconds with a cannon concept. The mass of the payload (cannon ball) dictates how much energy is required, but the speed needed is determined by the altitude alone



 
Ok, I stand corrected, mass doesn't matter, and that makes more sense. I actually should have clued in as I have watched countless dockings at the ISS. Gotta take some time and watch those videos tonight to wrap my head around it.
 
Fuzzydog said:
Ok, I stand corrected, mass doesn't matter, and that makes more sense. I actually should have clued in as I have watched countless dockings at the ISS. Gotta take some time and watch those videos tonight to wrap my head around it.
Click to expand...

And actually docking with something is incredibly complicated besides just matching orbits. If you match orbits and are behind, say the ISS, and you fire your rockets to catch up to the ISS, you increase your speed so your orbital altitude increases so you actually end up going above (in altitude) the ISS. What you actually do is fire your rocket in the opposite direction to slow down, now your orbit drops, so you end up going under the ISS and then raise the orbit back up, kind of like cutting a corner. As I recall one of the old missions (Gemini, Apollo?) had this happen where they were trying to dock or get near something and would line up and throttle towards it and then end up missing it and going in a direction they didn't want. I think Scott Manley or someone had a good video explaining it, and I'm not an orbital dynamist by any stretch, but it's counter intuitive how to catch up to something in orbit.
 
snivilous said:
Found it!
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Scott Manley is excellent, and KSP (Kerbal Space Program) is the best thing ever for learning orbits, I have no shame admitting it taught me a TON about how craft move in space. I wish the new game KSP2 was anywhere as good as the first. It's visually cool, but hasn't lived up to the first one from what I've seen (waiting for it to get better before I buy it).
 
AgitatedPancake said:
Scott Manley is excellent, and KSP (Kerbal Space Program) is the best thing ever for learning orbits, I have no shame admitting it taught me a TON about how craft move in space. I wish the new game KSP2 was anywhere as good as the first. It's visually cool, but hasn't lived up to the first one from what I've seen (waiting for it to get better before I buy it).
Click to expand...
Must admit I've never played KSP. Every now and then I get the urge to try it, but seems like it requires a bit more devotion and brain power than I'm usually willing to use at that moment haha. Though it's certainly excellent for demonstrating stuff on videos so I appreciate it for that at a minimum!
 
snivilous said:
Must admit I've never played KSP. Every now and then I get the urge to try it, but seems like it requires a bit more devotion and brain power than I'm usually willing to use at that moment haha. Though it's certainly excellent for demonstrating stuff on videos so I appreciate it for that at a minimum!
Click to expand...

It is definitely time intensive to do long missions, but the career mode progression brings the satisfaction in nice incremental chunks that don't take too much time. Little hops, exploring the planet, reaching space for the first time, reaching orbit for the first time, etc. Then the complexity ramps up as you start to reach out to the moons and planets, start adding detachable landers and rovers etc. It gets chaotic, but in the best way. And you can keep the designs true to form, or start cobbling together insanely goofy stuff that somehow gets the job done.

I'd say pick the first one up if you see it on sale sometime, even if you don't fire it up for months. Then just start tinkering
 
:lmao: Yeah KSP be like that. I play it in waves, but haven't done much in the last year

Cool thing today, NASA announced the three companies it has chosen to advance with lunar rover concepts. NASA put out the contract bid request a while ago and has been collecting bids for the next rover, so today was the initial selection. Essentially these three are awarded contract money to advance their designs further, then later on NASA will most likely downselect to a single provider for the actual deliverable down the road.

NASA selects three companies to advance Artemis lunar rover designs

Lunar Outpost:


53629763849_1552259171_k.jpg


Intuitive Machines (same folks that just recently has their nearly successful lunar lander land on the moon)

moonracer.jpg


Astrolab:

astrolab-ltv.jpg
 
Treefrog said:
Based on those images, maybe Irate should have bid.
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That's no joke haha. I'm honestly surprised that none of these seem modular, built out of lego blocks that can be rearranged to create various different configurations. Though then again they're not really designing for long term utility and versatility, just to meet the demands of these initial contracts
 
That new recap video is great. That view from the booster staring at one of its fins and lift points during the flames of the hot stage was new footage. Really damn cool

Also today they test fired B11. Everything looked great, and they posted official footage of it. Ship 29 also completed its test fire campaign a couple days ago, so it looks like their target of a May launch of IFT4 may be reasonable



B11:



The ship 29 static fire because it's B11s partner for IFT4:

 
Elon recently did a talk with the production teams down at Starbase about where things are going, a pretty good amount of info in here. The aspirational goal is to have a nearly fully self sufficient Mars colony within 20ish years





Some bullet points from the talk in the main post, and some screen caps of the slides in the reply:

 
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