How Not to Land an Orbital Rocket Booster [video]
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SpaceX has somehow managed to turn landing a booster from space into something almost mundane, but it bears remembering the failures that got them there.
Learning how to NOT land it is learning how to land it.
It was a good move regardless but don't underestimate the amount of time and money spent.
All of this should have been done a long time ago by the established players in the industry. It sounded crazy to them, but really the cost of experimenting with re-entry should not have been much and AFAIK they never even tried.
But it was still an expensive program with Grasshopper test vehicles, lots of failed tests and a reduced capacity on the boosters. "Just a little extra fuel" is a great oversimplification, there's much more than that in doing an atmospheric re-entry.
But a marvelous program it has been and I look forward to seeing their future progress.
And now they're going to have to do that anyway if they want to compete with SpaceX, so what the GP said is true, it's something established players should have done a long time ago, and they're going to be noncompetitive for a period of time as a result.
But if that $1 billion came from their margins rather than from investment, it means they wouldn't run out of funding unless they ran out of business, which is pretty cool.
"If Rocket is destroyed while operating for any reason, Customer will be required to pay the pro-rated portion of anticipated Rocket lifetime replacement cost, or insurance deductible, whichever is higher."
The part that made me laugh the most, however, was that Scott Manley had the top comment (when I looked, anyway).
For those who don't spend their off hours accidentally blowing up green videogame astronauts, or stranding them on distant planets, Scott Manley has the single most extensive tutorial series for Kerbal Space Program.
e.g.
ROU Sticky Throttle Valve
Edit: In case anyone is wondering about about the connection to the Culture, the SpaceX "Autonomous spaceport drone ships" are named after Culture ships:
https://en.wikipedia.org/wiki/Autonomous_spaceport_drone_shi...
Just Read the Instructions
and
Of Course I Still Love You
https://en.wikipedia.org/wiki/List_of_spacecraft_in_the_Cult...
Rather like 'Look, that's not an "Explosion"' as well... :-)
Edit: I'm hoping that the first manned ship on Mars will be "The Ends of Invention".... ;-)
Problem with Mars landings is the high turnaround time - while you can see what failed and fix it in a matter of days to weeks on Earth, with Mars you're looking at months to years of having another attempt.
Wonder how they'll get it done - practice on Moon first?
In fact, some of the best data and tests we have about landing big things on Mars come from SpaceX's first stage booster landings. The burn that the first stage does at the edge of space to slow down is in an environment very similar to that of the Martian atmosphere.
For example Pathfinder decelerated from 7.3km/s to 0.4km/s purely using it's aeroshell, before it even deployed the parachutes[0]. Now 0.4km/s is still pretty fast, but a saving of 6.9km/s dV is absolutely enormous.
Red Dragon was only possible because, with modifications to the capsule aerodynamics, the Martian atmosphere would brake the capsule enough for it to soft-land on the SuperDracos. There's no way a Dragon could usefuly soft-land on the Moon. It's just way too heavy for it's size. All that thick capsule hull is just dead weight for an airless environment. Given it's high dry mass the rocket equation demands huge amounts of fuel to compensate. The parameters are all wrong for the Moon because it's designed to use atmospheric drag to do most of the work.
On the moon, you don't have to worry about reentry at all, so no need for a heat shield or any sort of aerodynamic protection, just some way to do a propulsive landing.
On earth, you need the heat shield and some aero considerations, but you can land safely with parachutes alone.
On mars, you need to deal with reentry but also some sort of propulsive landing system for anything of reasonable size.
We should do it like old times: get team B, C, D and E and send multiple ships. Even with 75% failure we get one success. And the best are still alive on earth to advise those in space.
Same problem with health in space: we send people in peak Earth physical condition. Perfectly adapted to 1G with no radiation. Why don't we try sending people with what are considered physical defect on earth there and see if they're better adapted to space?
That sounds interesting actually. What if we sent up some handicapped people, or people with amputated limbs? Missing legs might be a burden on Earth, but a benefit in space.
Massively off topic, of course.
It is, by far, my preferred Culture book and the one that apply the best today.
With those out of the way though... they've attempted 10 landings so far this year and all have been successful. Third flight of a reused booster is planned for early next month.
...and fingers crossed for seeing all three cores from the Falcon Heavy test-flight making successful landings.
I'm bummed there isn't a better video of the March 2016 SES-9 failure (the only shot in this video is the droneship on the horizon).
That was the landing that punched a hole in the deck of the droneship.
You don't think these folks are wearing safety tipped shoes and cracking dirty jokes from time to time?
https://www.gannett-cdn.com/-mm-/caac49d6e3f44d10409a91a8bb8...
Twenty dudes in the middle of nowhere turning trees into a piles of logs are gonna be way more fun to hang around with than a team who's supervisor's supervisor could easily drop by.
Follow some people who work odd hours on Snapchat/IG. Way more screwing around happens on 3rd shift than 2nd or 1st.
IMO the morale boost of allowing people to screw around (relatively speaking) during normal operations offsets the material decrease in productivity because people are more willing to work hard in cases where you need maximum productivity.
The culture needed varies based on the nature of the work.
What works in an office doesn't necessarily work on a jobsite and vise versa. Even then it varies by the nature of the job. The typical "condom full of acetylene" would probably not go over well in a workplace that specializes in something highly regulated.
I am glad they finally made it out, if only in partial form, for folks to see. Landing is hard, and there was a lot of things that didn't work. And it is way more open than Blue Origin and their less successful flights.
In 20 years time we will be saying in amazement "you mean they used to just throw away the boosters after each launch?".
Bravo spaceX.
Glad to be wrong.
Your idea does make some intuitive sense. While lifting the single booster and even with just one of 9 engines turned down to minimum throttle, when the payload is gone and the tanks are near empty there's an enormous excess of power. The minimum thrust-to-weight ratio is still like 2:1. This means you have to run a "hoverslam" profile which reaches zero velocity precisely at the deck, otherwise you'll take off again. And it means you come in terrifyingly hot and fast, resulting in the explosions in the linked video.
With 7 boosters strapped together, you'd think there could be a more appropriate ratio of power and mass, which would enable a more controlled, sedate, hover-and-land profile. If the current 40% throttled down single-engine, single-booster TWR is 2:1, 3 engines would give you a 0.86:1 to 2.14:1 TWR. They could even turn on 3 engines at the outer corners in an equilateral triangle, and use both gimballing and differential thrust to control your descent.
It should be easy. You'd just get some struts and select hexagonal symmetry...oh wait, no, that's KSP. In reality, landing 7 boosters at once with a near-unity TWR would be much more expensive in terms of fuel. You want a hoverslam profile that's almost too fast to control, because then you can get your payload higher and faster. Right now, with the single 9-engine booster, they sometimes burn 3 of the 9 engines to land (giving a >6:1 power-to-weight ratio). They do this when they're short on fuel because for every second that they are airborne, they're suffering a 9.8 m/s hit to their delta-V. They want to come down as fast as possible to minimize time in the air.
or another plan would be to keep them together all the way to mars, and you have a habitation unit above the boosters which is their combined surface area.
when you launch the habitation unit you can later land another one next to it the to tile them together.
The one at 0:49 exploded just from tipping over.
Perhaps because they're huge i guess.
Your point is spot on though. Don't waste mass to account for failure modes that you can just avoid in the first place by landing upright.
They're extremely fragile. In fact, they're stored pressurized because laying on their side would damage them without the pressure keeping the walls rigid.
Of course I can't find any authoritative source on this, although there are a lot of random internet folks like myself repeating the claim. And I guess I'm throwing one more on the pile here.
I recall reading that they have equipment to maintain pressurization while the boosters are trucked to the launch site as well, so it's not just flight loads, in any case.
https://scontent-frx5-1.cdninstagram.com/t50.2886-16/2173252...