Some details on the SpaceX’s attempt to land its Falcon 9 first stage
This SpaceX press release gives some good info on the difficulty they face getting the first stage on Tuesday’s Dragon launch to land successfully on its floating sea platform:
To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky. During previous attempts, we could only expect a landing accuracy of within 10km. For this attempt, we’re targeting a landing accuracy of within 10 meters.
They are going to try however, and they will be filming their attempt all the way. Stay tuned for some very interesting footage.
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This SpaceX press release gives some good info on the difficulty they face getting the first stage on Tuesday’s Dragon launch to land successfully on its floating sea platform:
To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky. During previous attempts, we could only expect a landing accuracy of within 10km. For this attempt, we’re targeting a landing accuracy of within 10 meters.
They are going to try however, and they will be filming their attempt all the way. Stay tuned for some very interesting footage.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
If on this first attempt the F9 gets within a few hundred meters of the barge, I would consider that a success. To my knowledge the small steering wings added to guide the F9 down haven’t be used on such a flight. They’ve only been tested on the short grasshopper test flights which in no way simulates the full flight down from near orbital heights and velocities. I can’t imagine that some tweaking still remains to properly guide the F9 down to a 10 meter target in the middle of the ocean.
If a soft landing on the barge is indeed achieved on the first attempt, it will be a VERY impressive achievement. They have to have some rather spectacular simulation software for the guidance control algorithms to be coded against.
Can we assume the purpose of landing on a barge is safety for ground-dwellers, ease of returning the rocket to its spaceport, or both?
The barge is the next incremental step towards re-usability with considerations towards both safety for those on the land while demonstrating that 14 story object traveling at the speed of a rifle bullet can be guided down backwards with adequate precision. However, I believe the ultimate goal for the F9R is flyback of the first stage booster all the way to the launch site or somewhere else on dry land along the coast. The barge is just a stepping stone.
I agree with mpthompson, that the preferred method is to return directly to the launchsite/spaceport, but that requires extra fuel to turn around and then to stop the rocket’s “forward” motion again at the spaceport. However, the rocket would be immediately available for refurbishment, with no transportation-time delay spent on the barge.
The barge would still be available for launches in which the payload weight does not leave enough fuel in the first stage for it to return to the spaceport or in which the spaceport does not have a “landing pad.”
Landing on a rolling, rocking, pitching barge with who-knows-what kind of winds and gusts is quite a test of the system. Even after it lands on the barge, the rocket has to be prevented from tipping over – or blowing over – the side.
To paraphrase a song, if you can land it there, you can land it anywhere.
Good one.
Live coverage on their YouTube channel and the NASA feed is over at Spaceflight Now is starting as I type.
http://youtu.be/Ohnnl4nOcGU
http://spaceflightnow.com/2015/01/05/spacex-5-mission-status-center/
The steering panels are the same design as ones used on new free fall guided bombs and hypersonic missiles.
They are pretty good. They just needed to be scaled up to match the mass of the rocket.