SpaceX nails triple booster landing after satellite delivery
bbc.com
bbc.com
The Heavy costs $90 million per reusable launch with a 64,000 kg payload, or $1400 per kilogram.[1]
Current versions of the Falcon 9 and Heavy can fly ten times with virtually no refurbishment between flights.[2] The only part they throw away is the $7.5 million upper stage.[3] Their expendable cost is $150M and they haven't really started reusing yet, so if they actually reuse each rocket ten times, they have a lot of room to lower prices; ten launches would be $($150M - $7.5M) + ($7.5M * 10) = $21.75M per launch, or $334/kg for the rocket itself. Launch cost won't be quite that low because they also have labor, fuel, and so on, but it looks like they can get well under $1000/kg just with the Falcon Heavy.
The larger and fully-reusable BFR should do even better.
[1] https://en.wikipedia.org/wiki/Falcon_Heavy
[2] https://www.space.com/spacex-falcon-heavy-triple-rocket-land...
[3] https://www.nextbigfuture.com/2019/04/spacex-recovered-6-mil...
Probably also have to build in enough slack for occasional failed landings, but we don't know yet what the failure rate will be after the kinks are worked out.
I wouldn’t be surprised if spacex also enter the satellite building business after mass producing starlink.
Musk has expressed skepticism, famously asking "what's the conversion rate?" The answer is that microwave transmission is 40% efficient with today's technology. This isn't bad considering that average daily sunlight in geosynch is five times higher than on the ground,[1] and you don't need much storage or backup.
The early SPS designs were hugely expensive monolithic beasts, but current designs use lots of identical parts (of several varieties) that self-assemble in orbit, so you get economies of scale with factory production.
A year ago I read the book The Case for Space Solar Power [2], which broke down the costs in detail. With pre-SpaceX launch costs they got 15 cents/kWh, including manufacturing and ground stations. I plugged in the BFR cost Musk was claiming (I think I used $50/lb) and got about 4 cents/kWh.
[1] https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on...
[2] https://www.amazon.com/Case-Space-Solar-Power-ebook/dp/B00HN...
The reason is attitude control. Reaction wheels can be used to orient the satellite, but eventually reaction wheels get saturated. At that point you need to use thrusters to cancel out the reaction wheel saturation. Those thrusters require propellant, e.g. something to push against. The greater the ratio between propellant mass and structural mass the satellite has, the longer it can remain operational before the propellant runs out and your reaction wheels finally saturate, leaving your satellite tumbling useless without attitude control.
It will be interesting to see if Falcon Heavy, and more likely starship, have a significant impact on what sort of satellites are built, and the way they are built. If they do it will probably take years before we see any changes, however spacex is ideally positioned to cash in on a transition to more mass-produced satellites if that does happen.
EDIT: scratch that, apparently the recovered the fairings as well per a comment below. Neat!
So 5 out of 5...
Being a SpaceX launcher, as the article indicates, means they can accept higher risks, but in turn has a greater financial risk to the company. It's times like this where I'm glad SpaceX is a private company.
https://www.reddit.com/r/spacex/comments/bc8105/arabsat6a_el...
The first reuse mission seems to be an internal one though.
The additional suggestion by a commenter in the Reddit thread that "they've saltwater hardened the fairings" is speculation.
And we know that Elon Musk only ever tweets true information.
A financial risk you can count as R&D cost.
SpaceX has also positioned itself for some launches that would be acceptable to loose, like the deployment phase of starlink: loosing a few mass-produced satellites has to be much cheaper than loosing a big one-off satellite that takes months to rebuild.
[1]: https://www.space.com/41614-spacex-mr-steven-catcher-boat-up...
google.com googlesyndication.com googletagmanager.com gstatic.com
When rendering the page, so this just proves that avoiding sending data to google is very tricky indeed!
Here's a great video of the entire flight and landing of the side boosters in one shot, made with custom tracking software: https://www.youtube.com/watch?v=cEZZkEXAD6Q
Seeing a launch/landing in-person is on my bucket list.
If you get time, go look for the first FH booster landings. The timing is almost perfect and the long exposure images looked beautiful.
On reddit a lot of people enphasised that it was to avoid interference. Which interference, no one knows.
Most impressive part for me was that you see the booster make it's landing burn and touchdown BEFORE you hear the landing at the observation site.
To hear the roar of those 27 engines and feel it vibrating on your chest and the bleachers is an emotional experience. Then you can see the boosters coming back, and their entry burn and you can follow them down to their landing zones. A few seconds later you hear the sonic booms.
While all this is happening, you also have the energy of the happy crowd cheering and celebrating what humans are capable of doing.
It gives you hope and an exciting future to look forward.
If it's not obvious, the main core landing was much harder this time around, because of how fast it was going due to the two boosters imparting a lot of extra speed on it before they separated. If you think about it, it'll have somewhere between 1x and 3x the velocity of a normal Falcon 9 core
The FH is apparently capable of 8,000kg in a reusable GTO launch ( https://en.wikipedia.org/wiki/Falcon_Heavy#Capabilities ), and this satellite was only 6,000kg. So it looks like there would be plenty of fuel available to slow the core down well below the survivable maximum.
Swinging a bat at a 10mph ball is the same technology as swinging at a 90mph one. I don't think anyone would say that they were equally as easy.
In the case of a bat swing, to bat the ball faster, your muscles need to be stronger, and the ball and bat need to withstand greater pressures. In the case of a vehicle travelling through space / thin atmosphere, it only needs more fuel to burn to slow it down. Analogously, you don't parallel park a car from 70mph, having travelled somewhere on a highway.
Here's a graph a booster's speed over time, showing the reentry burn: https://i.stack.imgur.com/xFYIh.png ( from https://space.stackexchange.com/questions/20246/what-is-this... )
Other sci-fi, maybe.
Totally removes all agency from protagonists. Every fight becomes a deus ex machina - "welp, our targetting subroutines continue to be superior to their maneuvering systems so they died. Hooray us?"
Or I guess more probably just a numbers game: "welp, our effective weapons range is larger than theirs, so that's that" with an MCRN exemption clause.
Sounds like a book by Iain M. Banks.
I suppose that's why so many contemporary thrillers or even far-future science fiction movies devolve into hand to hand combat for the climactic showdown. It looks more interesting. (Though personally it makes me groan and want to throw things at the screen.)
Probably no, we can't stop having some of that. We can have her alternative, and, in fact, a lot of space combat in movies and TV is not resolved that way (both because it involves highly automated maneuver and targeting, and because, especially for combats that determine the outcome of the story, it is resolved by a social or technological advantage, often one provided by the quest making up the body of the plot, not by maneuvering or targeting (except to the extent that technical or social advantage impacts those abilities.)
Yet imagine a world where Elon did not exist and thus SpaceX did not. Much of what he's done is stuff that we could have been working on decades ago. For some time we were. NASA as early as the 70s had already laid out plans for a Mars expedition including a tremendous space ship that would be assembled and fueled in orbit to take 5 man crew on a 600 day manned expedition to Mars, including landing of rovers similar to the moon.
Those plans got canned by Nixon, and space never really recovered. Not only did we not "inexorably advance" in space, we regressed. Today we're struggling to do a manned flyby of the Moon - when we went to having barely put a man in orbit in 1962, to putting a man on the moon in 1969. The point of this is that technology does not advance by itself, let alone inexorably so. I think it's extremely likely that had SpaceX not come to exist, it's entirely possible that we would still be effectively where we were at near the turn of the century.
Progress of our species, in spite of there being billions of us, is still dependent upon the individual. And SpaceX's plans have very much followed the old quote of Gandhi, "First they ignore you, then they laugh at you, then they fight you, then you win." But of course we've not yet won. As remarkable as this achievement is, it's but the starting line for where we need to be. And that line will not move forward unless we move it forward. But "we" does not mean waiting for somebody else to do so. As SpaceX and Musk have demonstrated, it's ultimately up to the individual to get up and move that line forward -- for the betterment of all.
Really inspiring. This thread got picked up by many news sites. I just googled "spaceX engineer lumberjack" to find this.
The big difference in outcomes comes from the leadership. These other companies are headed by people of different abilities, different ideologies, different technical abilities, and so on. This is why they've all been, more or less, surpassed by a company started on a shoestring budget in 2002.
In other words, I imagine if you had let Musk have complete control over ULA (united launch alliance - an arguably anticompetitive merger between Boeing and Lockheed) he'd not only achieved as much as he has already, but likely far more given their vast resources - both economic and human. Similarly, if you put Marilyn Hewson [1] (president, chair, CEO of Lockheed) in charge of SpaceX's people in 2002, SpaceX almost certainly would have catastrophically failed.
Is it precise modelling and standard control algorithms, or something more exotic like neural networks?
http://www.larsblackmore.com/losslessconvexification.htm
See also: https://www.aa.washington.edu/facultyfinder/behcet-acikmese
This technique is based on "the idea of relaxing the nonconvex control constraints to a convex set in such a way that the optimal solution to the relaxed problem is guaranteed to be the optimal solution to the original problem."
By "relaxing", what they mean is that the new model (the convex set) actually contains some parameter values that aren't achievable, but OTOH it is geometrically susceptible to being analyzed by an efficient optimization technique. So it's a clever replacement of a hard problem with an easier one. The complex bit, which I don't understand, is how they show that this replacement will always give the same value as if they had solved the (real) hard problem, i.e. that the solution will never actually use the "illegal" parameter values.
Maybe someone else can give more insight.
"In this paper, we unify the convex optimization approaches of [1], [2], [17] and extend them to handle thrust pointing constraints. While convexifying the problem with nonconvex thrust pointing constraints, we develop a geometrical insight into the problem that establishes a connection with “normal systems” [18]. A normal linear system is defined in the context of optimal control theory where the system is said to be normal with respect a set of feasible controls if it maximizes the Hamiltonian at a unique point of the set of feasible controls. In the case when the set of feasible controls is convex, a system being normal implies that the Hamiltonian is maximized at an extreme point of the set [18]. Our convexification result has a similar geometric interpretation since it establishes lossless convexification by ensuring that the Hamiltonian is maximized at the extreme points of a projection of the relaxed set of feasible controls. This set is then shown to be contained in the original nonconvex set of feasible controls, thereby estab- lishing that we can obtain optimal solutions of the original nonconvex problem via solving its convex relaxation."
IIRC it purposely missed the droneship by only a few hundred meters, but it was going something like 300 miles per hour!
Until the last moment it also doesn't target the barge itself, but slightly to the side. Only very shortly before landing does it correct the target to the actual landing position. So in most cases it would simply hit the water instead of anything else when there is a major issue.
For the real thing, watch the SpaceX video directly from YouTube: https://youtu.be/TXMGu2d8c8g?t=1181