We’ve had a few lively and informative threads around here about SpaceX, reusable rockets, and other developments in spaceflight, so I’d thought I’d let y’all know that a significant SpaceX launch is coming up.
Today, Dec. 21 at 8:29 PM Eastern Time (UTC 1:29 AM Dec. 22), SpaceX will attempt their first launch after the June 28 failure. Notably, the first stage will fly back and attempt to land at the launch site, rather than on a barge a couple hundred miles away from the coast. This is also the first launch of an upgraded Falcon 9 rocket that has up-rated engine thrust, and a slight tank stretch and oxidizer supercooling to carry more propellant. These upgrades give enough margins so that the first stage will be able to land after nearly any launch (previously it had to be expendable to launch heavier or higher orbit payloads).
SpaceX will stream the launch and landing live (official page, youtube mirror). The stream will begin about 20 minutes before the launch. There’s also a live reddit thread that is frequently updated with every scrap of relevant information, if those streams aren’t enough.
There’s no guarantee of a launch today, however, and certainly no guarantee of a successful landing. The current forecast has about a 20% chance of cancelling the launch due to weather (don’t want to launch through a cloud that has the slightest chance of producing lightning!) SpaceX has also had some technical issues dealing with the superchilled oxygen that’s new on this rocket.
In any case, I’m going to be glued to my computer for the next hour or two…
I watched Star Wars yesterday and loved hit, but holy crap it doesn’t begin to compare to the excitement and exhilaration when the Falcon first stage actually touched down. God damn! I can only imagine what it was like to actually be there.
Glad to see the Orbcomm satellites are beginning to deploy as planned as well.
SpaceX still has a long road to go before actual first stage reuse, but this was a hell of a first step.
Entirely aside from the primary mission and first stage landing, this was also the first flight test of their up-rated “full thrust” engines, stretched second stage, and densified propellant. Not to mention that it’s their return to flight after the previous launch failure. A huge success on all fronts.
For those wondering what densified propellant is: like most liquids, liquid oxygen (LOX) and kerosene (RP-1) get more dense as they get colder. You can thus pack it more densely in the tanks the more you chill them. Traditionally, the kerosene is kept at room temperature and the LOX at its boiling point. This is relatively easy to maintain, but with extra work you can chill the liquids in advance to increase their density.
Aside from tankage efficiency, this has another benefit: it increases the mass flow rate of the engine pumps. Denser propellant means more mass per second, which means more thrust. More thrust means you can take even more propellant along and still lift the rocket.
Densified propellants have been used before, but I believe SpaceX set another world first in that they’ve chilled the LOX to lower temperatures than anyone before them.
The landing site is a few miles south of it’s launch site at SLC40. It’s at the old SLC13 launch site so good viewing from the restaurants at Port Canaveral and the beach at Jetty Park.
I remember the old science fiction movies from the 50’s and 60’s of people going to Mars. The rockets always landed backwards on their tails. And so 60+ years later… rockets can now land on their tails.
Heard from folks down there in CB, (Cocoa Beach) sonic boom of the landing rocket knocked some windows out.
Nearby residents were apparently warned about the sonic boom–first one since the Shuttle landings (at least from a returning spacecraft). A historic moment in and of itself.
Quick video with the booms here. The people seem concerned :). Three quick pops, with the last two very close together. Maybe a shockwave from each of the engine side (the “front”), the top (the “rear”), and from the grid fins?
There’s also supposed to be some additional tests on the 2nd stage, to make sure that multiple engine restarts were working properly before upcoming missions that needed them to achieve geosynchronous transfer orbit. Has SpaceX done 2nd stage restarts before? Or was this just precautionary testing for the upgraded Falcon 9?
Meanwhile, Elon Musk has been teasing us about the next rocket SpaceX is working on, the Big Fucking Rocket and the Mars Colonial Transporter. “It’s really big. There’s not been any architecture like this described that I’m aware of.” Various rumors have suggested that it’ll be somewhere between substantially larger than the Saturn V to HOLY SHIT I CAN’T EVEN COMPREHEND. In the wilder speculations, the second stage will fly direct to Mars and land propulsively. For the return trip, it would generate fuel on Mars, and could even fly direct from the Martian surface all the way to landing on Earth.
I don’t even know what to say without gibbering now.
Did it? From the animation (the pencil being shot over the Empire State Building), it looked to me like it landed on its “nose” - in effect, it has engines at both ends; one for liftoff, and the other for landing.
The first stage has nine individual engines. At takeoff, those nine provide only about 1.2 gees of acceleration. Only one of them is used for the final landing, however, and at close to its minimum throttle levels (rocket engines tend not to like being throttled to a small fraction of their full thrust levels).
Even at that, the stage has to perform a “hoverslam”, which is to say that the minimum deceleration is more than one gee. So it can’t just hover in place a bit to get its bearings; it has exactly one shot at the landing. It wouldn’t have enough propellant to hover anyway.
There’s probably going to be a hell of a lot more. I understand that the first stage is packed with GoPros, but up til now they’ve never been recovered.
