SpaceX Falcon 9 rocket - successful landing on droneship, not so successful leg function...

(Norsk)
This Sunday (January 17th) SpaceX launched one of their Falcon 9 rockets, on a mission to place the Jason-3 satellite into low earth orbit. Let's look a bit at the company, the rocket and at the satellite before we take a look at the mission itself:

SpaceX:

Logo (actually from Wikipedia)

The company was founded by Elon Musk in 2002. (Yup, the same dude that is responsible for the awesome Tesla invasion we are experiencing here in Norway. He has got other achievements under his belt also, but I will get back to him at a later date, since I want to write about a biography of his that I have read.) Their goal is to make space technology more available and ultimately contributing to the colonization of other planets. Read more here.

Falcon 9:

Image from Wikipedia

The Falcon 9 is a two-stage rocket. The first stage has nine engines, which gives it enough redundancy to safely complete its mission even if one of the engines should fail and shutdown. In 2012 the Falcon 9 made history by allowing the first ever commercial company to visit the International Space Station. The original goal for the rocket is for it to deliver humans into space (with the Dragon spacecraft). And last I checked, NASA has awarded a contract to SpaceX towards the purpose of delivery of astronauts to the ISS. Basically a "show-us-you-can-do-it" contract, including at least one crewed space flight (with at least one NASA astronaut on board), maneuvering in orbit and docking to the space station, all the while verifying their capabilities. Read more about the Falcon 9 here and the NASA contract here.

Jason-3: 

Image from NASA

The goal of this satellite is to make highly detailed measurements of sea-level on Earth. This will allow scientists to gain insights into the circulation in the oceans and changes in climate. Read more about it here.

The mission!

Right, so, the Falcon 9 was to launch from Vandenberg Air Force Base and deploy the Jason-3 satellite into low earth orbit. That was the main mission. And it was successful! But... Let's face it, considering ALL of the satellites that have been launched into space, this was not exactly something to brag about. However, SpaceX had an additional mission for the Falcon 9, or, at least for the first stage of the Falcon 9. They were going to try to recover it, instead of letting it crash into the ocean somewhere as is usually done.

A few days before Christmas 2015, SpaceX launched another Falcon 9 rocket from Cape Canaveral Air Force Station, and then proceeded to LAND the first stage afterwards. Take a look in the clip below:

Image from SpaceX

Now that is REALLY cool! But this time around they could not land the first stage on land, but had to use their "Just read the instructions"-droneship. Basically a remotely controlled rocket landing pad at sea! Read more about the droneship here. Just the idea sounds totally crazy, but Elon gave a short explanation of why this had to be in two tweets:

If speed at stage separation > ~6000 km/hr. With a ship, no need to zero out lateral velocity, so can stage at up to ~9000 km/h.

— Elon Musk (@elonmusk) 17. januar 2016

So basically, placing satellites into low orbit requires huge velocities, and if the velocity is more than 6000 km/hr when the first stage separates from the second stage, then it is going too fast to be able to land on land, but can still land on a ship. But, anyone that has ever read about or maybe seen a documentary or fairly realistic movie of a hangar ship should know that landing on a moving ship is really difficult compared to landing on a land-based area. So this means that the landing this Sunday would be much more difficult than the one before Christmas, since it had both a higher start velocity and a moving landing pad. If the twitter reports were correct there was about four meters of waves too, just to make things interesting.

So onwards to the landing this Sunday! The rocket actually nailed the landing itself! Incredible! But then the SpaceX team experienced an RUD... A Rapid Unscheduled Disassembly... In one other word:

Thanks to Vadich at Deviant Art for this illustration

The landing went well, but it looks like one of the landing legs gave, toppling the rocket (Note to self: DO NOT topple space rockets, they are not built for that kind of use...) making it explode. You can watch it in the clip below:

Personally, I think they are being a bit unfair in writing "attempted landing". You can clearly see that the landing itself was a success, and that the leg gives out when the thruster stops, in other words once it has to hold the entire weight of the rocket up. So there was an equipment failure directly after the landing.

But anyways, the SpaceX team will get huge amounts of "lessons-learned" from this mission, greatly increasing chances that the next one will be even better. And, let's face it, at least they have learned something from this, as opposed to the alternative where they just let it crash land in the ocean, never to be seen again.

Some of you might ask: Why? Why are they landing the first stage? Because building a rocket is not exactly cheap, although SpaceX has managed to build them alot cheaper than what has been done in the past already. Their aim is to make them even cheaper, because only when it gets cheap enough will we see widespread human activity in actual space. By landing the first stage successfully, they can refurbish it instead of building it from scratch, saving costs and making the next rocket cheaper. So even though they might fail in recovering the first stage from time to time, it is still waaaaay better than not even trying to recover it.

Next week, I will write about the Musk biography I mentioned at the top of the post, it is a good book, so I hope you will read my recommendation of it :)