CodeRedR51
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Space In General
- Thread starter BubbleBelly542
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CodeRedR51
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Booster 5 is getting some sun currently.
CodeRedR51
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This is amazing and worth a double post.
Danoff
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The catch concept seems like it works better than landing for a few reasons. But it also requires a giant tower, the kind which would be tough to make on mars.
It kinda got me thinking though, a lot of these SpaceX boosters are coming back to the same platform they launched from. But aren't these boosters going to orbital insertion? Surely they're not doing a full orbit before returning to the platform, so this must just be staging before substantial horizontal velocity is imparted? Otherwise the booster would simply be too far down rage to return.
I suppose a fair number are landing at sea, so those must be the ones delivering orbital payloads. This animation then kinda suggests a sub-orbital delivery, as does the whole catch concept really.
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CodeRedR51
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Most Falcon 9 boosters land on a barge in the ocean down range because they don't have enough fuel to do a "boost back burn" and return to the launch site. Once the 2nd stage separates it keeps rising until it reaches max coasting altitude, then gravity takes hold and starts to bring it back down. An entry burn and separate landing burn slow it down enough to land on the barge.
As far as the Super Heavy booster is concerned, I think their plan is to do the same as I stated above, but be caught with a similar tower on a repurposed oil drilling platform down range. If the booster has enough fuel to return, it will be caught with the tower at the launch site. For the first several test launches, I expect it to come back to the launch site.
The only vehicle going to Mars would be Starship, and I have no idea what their plan is yet.
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Danoff
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I guess that makes sense, although a tower that beefy seems difficult to do on an oil platform, but it does make sense.
Like this:
I guess I just hadn't thought very hard about how much delta-V must be used to return these rockets to their original launch site. For an orbital payload, it does seem like it should be fairly substantial. I guess I had mostly been concentrating on the fuel it takes to control and stop the fall, but performing a burn to return back upstream to the landing site also seems significant.
Edit:
I'm seeing some rough numbers online like 15% of fuel used to return to landing and land.
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CodeRedR51
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Not sure this image is 100% accurate. I don't recall the booster doing a 'flip' maneuver. They usually just reorient themselves from #2 to #5 slowly and then come back down. You can see it here between 2:00-3:00:I guess that makes sense, although a tower that beefy seems difficult to do on an oil platform, but it does make sense.
Here's a good video of a "return to launch site" landing.
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The ability to return to launch site as opposed to landing on a barge depends more on the payload weight and not so much on what orbit it's sent to, I think. I'm not sure the booster trajectory is all that different, and I think the second stage or the payload itself handles whatever is needed to achieve the desired orbit. if the payload is light enough, the booster can carry enough fuel to burn back to the launch site.
The delta-V is significant, and it's why Falcon second stages are not recovered. The Starship orbital missions could be thought of as basically a recoverable second stage. De-orbiting and landing is HARD!!
The delta-V is significant, and it's why Falcon second stages are not recovered. The Starship orbital missions could be thought of as basically a recoverable second stage. De-orbiting and landing is HARD!!
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Who's full of hydrazine and dinitrogen tetroxide oxider and (finally) ready for a trip to space?
THIS GUY!
The JWST's ultimate destination will be the Earth-Sun L2 Lagrange point, some 930,000 miles away from Earth. Which means, unlike Hubble, if something isn't working right it's much too far away to send someone out there to fix it. But presuming something doesn't get stuck or misaligned, it'll be much more capable than Hubble is:
THIS GUY!
The JWST's ultimate destination will be the Earth-Sun L2 Lagrange point, some 930,000 miles away from Earth. Which means, unlike Hubble, if something isn't working right it's much too far away to send someone out there to fix it. But presuming something doesn't get stuck or misaligned, it'll be much more capable than Hubble is:
Danoff
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I'm mostly just considering the difference between an orbital payload (ISS astronauts) rather than a sub-orbital payload (William Shatner).
The 1st stage trajectory would change quite a bit depending on the targeted trajectory. Do payload masses really vary significantly for a single rocket? I'd have thought that the payload ends up generally maximized for a given launch vehicle. So, for example, if you need a spacecraft delivered to a polar LEO insertion, I'd expect that if the launch vehicle could handle another kg, you'd end up with 1 more kg of fuel on the spacecraft - because basically you will use it. The idea of unused launch vehicle capability is a bit foreign to me, but maybe it's common and it's just not where my experience is.
I guess SpaceX must have it on some kind of pricing menu. For the same launch vehicle they can say it costs $$$ to deliver mega kgs to the target orbit, $$ to deliver less mega kgs to the target orbit, and $ to deliver mini kgs to the target orbit. The $ representing cost savings by burning back to the OG launch site, the $$ representing less savings by burning back to the ocean platform, and $$$ for what they called "rapid unscheduled disassembly" in one chart above (but which might be scheduled).
Sure. But even just cancelling out some of the dV from the first stage is still a big cost if the ultimate target is orbit. Not so much for celebrity joyrides and other sub-orbital adventures.
I'm impressed and surprised all over again that the 1st stage on an orbital launch is capable of returning to the original platform under any circumstances. If I'd had to guess going in, I'd have said it would take way too much fuel. You're pitched too far over, and headed too far down range by the time separation occurs. I should have realized this earlier, I'd seen SpaceX pull this trick, I just hadn't really thought hard enough about where the 1st stage was going to be sufficiently impressed.
Something about that catch animation really drove home that it's returning to the exact spot where it left.
Edit:
Unlike in this awesome photo, which shows the whole thing, but returning to a slightly different spot. The graphic I posted earlier indicates 200 mi downrange for the landing, this looks like something in between.
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I heard the Space-X on-camera teenagers (at least they look like teenagers to me!) say that the difference between barge and cape landings was payload weight. More weight to orbit means the booster doesn't have enough fuel for a cape landing. Even a barge landing isn't a simple ballistic target, as there is still a trajectory change to not go too far downrange. I'm assuming there's a realistic range limit on the landing droneships themselves.
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- a baby, candy, it's like taking.
- TexRex72
Boy, that's a niche.
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Look, it's been a slow week for Japanese flying squid related news so I had to go a little more mainstream today, okay?
CodeRedR51
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Booster 5 was moved to behind the Starbase sign. Reason unknown...
Edit: that was actually mid-transit. It ended up chilling next to SN15 and SN16. Probably to free up space in the high bay.
Edit: that was actually mid-transit. It ended up chilling next to SN15 and SN16. Probably to free up space in the high bay.
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In the "who are they again?" department, UK company Orbex has started assembly of a Scottish test-launch platform. They're planning on building a spaceport near Sutherland sometime next year for the for-realsies launches as well.
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Did you know that one of the dangers of living in a zero-g environment for extended periods is that fluid will gradually build up in your head and squash your eyeballs, causing permanent vision problems? Thankfully, science has just developed a kinda scary looking solution for that.
CodeRedR51
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Booster 4 is being lifted onto the launch table as I type this.
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I don't see how that'll work. There is nothing there, which is fine for launches, but there's no infrastructure. All the roads in the area are single track with passing places so I don't even see how you can get materials in to build a spaceport never mind getting a launch vehicle there.
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Presumably they're either going to do significant upgrades to the road network, or more likely convince the local government to foot the bill for doing so by dangling the nebulous promise of "more jobs" in front of whatever politicians are looking for an easy bullet point to add to their re-election campaign. That's how Amazon distribution centers and other large corporate facilities tend to get their needed infrastructure on this side of the puddle anyway, so I presume it's not much different elsewhere.
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Danoff
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59 deg 30' N is pretty sweet. Plesetsk Russia is 62.8 deg N, which is, I think, the most northern (at least among sizeable launch facilities) out there. Or it was 20 years ago when I learned that. Sutherland would be pretty choice for polar launches.
Edit:
Maybe Andøya which it looks like started some kind of expansion in 2018.
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Ingenuity is still buzzing around up there too, it's clocked a full half hour of flight time over 17 flights. Pretty impressive considering they were only planning for a maximum of 5 flights originally!
CodeRedR51
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