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SpaceX Successfully Tests Nine-Engine Cluster
the_other_chewey writes "At their test facility in Texas, SpaceX, the privately funded space-flight company, have successfully tested their nine-engine cluster which is planned to provide the heavy lifting capability for their Falcon 9 and Falcon 9 Heavy rockets.
The firing lasted three minutes (a full 'mission duty cycle,' i.e. a simulated launch) under full power, delivering 3.8MN (or 855,000 lbs.) of thrust. SpaceX have made a video of the test available. The Waco Tribune has a short report about it, with comments by locals."
Awesome, simply awesome. Glad to see they passed the test, or at least didn't blow up. Hope they got some good test data. Ideally they were giving it some control feedback to make sure the gimbals etc that aim the rocket were all responding correctly, performing their orbital roll etc. Getting the most bang for the buck (without the bang!) since I'm sure this test cost a not-so-small fortune considering the fuel used.
As for the "why didn't it take off" question, it was pretty firmly fitted to the ground. Despite it's size and total impulse capacity, that's over a 3 minute span. It's not designed to lift more than itself and its payload, at a marginal acceleration. The thrust output is variable also, and can't be allowed to crush the payload with G-forces. Despite its massive size, it wasn't going to be going anywhere.
I'd be interested to know the power curve on the rocket. Most of the fuel is actually spent lifting the FUEL. From one viewpoint, the engine could be constant-thrust, and would accelerate slowly at first, and increase its acceleration as it consumed fuel and became lighter with the same thrust. Or it could back off the thrust as it got lighter, to prevent the g-forces from acceleration from becoming too great for the vehicle or its payload. I'm sure the power-to-weight-ratio could get really high as it nears the end of its firing if it were left at maximum thrust. Anyone happen to know the power curve or acceleration curve on ascent? I thought I read somewhere they try to keep the g-forces under 8g, and not for too long of a period of time, at least for crew.
I work for the Department of Redundancy Department.
Does anyone know how tall that test stand is.
The Falcon 9 first stage on top of the stand is about 25 m high (I've assumed it's half the total height of the Falcon 9). The stand appears a bit over 2x as high as that first stage, so 60 m/180 ft would be my initial guess.
Actually, there is someone there saying 'this is what happens when you elect Obama.'
Unless NASA releases money for COTS-D very soon, we will still have a manned launch gap. The Falcon 9 and Dragon are man rated, but to launch people into using the Falcon 9 and Dragon, you need much more. You need a Launch Escape System and a Emergency Egress System. Neither of these is currently in development at SpaceX and both have a long lead time to develop.
Without the additional COTS-D money to start development on these systems, SpaceX will not carry people until they find the money from other sources to fund these development efforts.
engineers are all basically high-functioning autistics who have no idea how normal people do stuff
The Falcon 9 is 54.9 meters tall. The first stage is a bit more than half that height, so call it 30 meters.
"I do not agree with what you say, but I will defend to the death your right to say it"
This test was the last major step before shipping it to the cape, so it seems the schedule on the website with delivery scheduled by Q408 is accurate. As far as when it launches... my WAG is by summer. From what I can tell getting it to the cape is largely a move to show the new administration "hey, remember us and COTS", so there may be a bit more work that has to be done on it.
Here's hoping the lessons from F1 carry over and there aren't new issues to discover.
The website says the top of the BFTS ("Big Falcon Test Stand") is 235 feet high. Presumably this includes the blue "Stairway to Heaven" running up the side of the first stage, so I'd say the concrete stand is probably about 150 feet... having been up to the top I must say it's impressive, and a little scary. Fortunately theres an elevator up to the concrete platform, but only too steep stairs up to the top from there.
Also, while I love the company, I woudl say that they did just buy the site, including the test stand from another company that I can't remember the name of off the top of my head.
I work for the TX facility. The concrete tripod is 120' tall and the legs are 10' in diameter. The stage is 85' tall and 12' in diameter. You can see it 25 miles away when you are driving to work. It is pretty awesome (-;
850,000lbf (lbf = pounds force) is a relatively small load. It is easy to forget exactly how strong steel is in tension: using standard 50ksi steel (typical structural steel), only about 18 sq-in would be required to hold the rocket down (albeit with no factor of safety).
For comparison, the main cables in the George Washington suspension bridge in New York each carry ~260,000,000lbf, and are designed to resist almost 3 times that load. While the amount of thrust developed by the Falcon 9 is seriously impressive for a lift vehicle, it is trivial from a ground-based engineering standpoint.
There is a reason structural engineers work in kips not pounds (1 kip = 1000lb), and yes IAASE.
under construction
There are nine engines in a cluster. Burn time for the cluster is 178 seconds. All engines run at full throttle. At t+160s, they shut down a pair of engines to reduce the g loading slightly, but otherwise it's constant thrust. Remember, though, that liftoff acceleration is very mild -- about 1.2g, iirc. For a given engine thrust, you usually improve payload mass by adding tankage until it can just barely leave the pad.
You would need one HECK of a heat shield to withstand flying at escape velocity so deep in the atmosphere. I'm sure it could be done, but it would look like a meteor flying up instead of down.
I came across an additional amateur video from farther away after submitting the story:
http://uk.youtube.com/watch?v=i9n6rYoSGNQ
SpaceX' video unfortunately lacks the proper amount of bass
to really give a sense of the sheer power shown.
Dear Greater Waco Area Residents, We appreciate your feedback regarding our recent test as it allows us to improve our notification process to the surrounding community. Since we began operations in 2003, SpaceX has conducted over 2000 tests, and nearly ten have been multiple engine tests at similar times of day. During these previous tests, we did not receive complaints from citizens in your area. The weather on November 22, with low clouds and cool temperatures, drastically affected the distance the sound and light travelled. We began test procedures for this particular test at 7:00am on Friday, Nov. 21 and executed it as quickly as possible, working through hundreds of pages of procedures designed to keep the community, staff, and hardware safe. While no further tests are planned for this stage in McGregor, in the future we will increase our notification to include local news media and law enforcement in McLennan, Coryell, Bell, and Falls counties. As a resident of Central Texas for over 25 years, with family in the area, it is extremely important to me, as well as all of SpaceX, who choose to raise their families in the area, that our testing is safe for local residents. The propellants used are non-toxic and environmentally friendly, In factâ"the Falcon 9 burns a higher grade of kerosene (more environmentally friendly) than a 747 and burns only about half of what a single 747 flight does. The smoke you may have seen was composed mostly of steam and dust. SpaceX strives to be a good corporate neighbor, bring high technology jobs to the area, and stimulate the local economy. We are proud to have operations in McGregor and make use of facilities which have historically played such an important role in American history. Engines which propelled American astronauts to the moon and back were developed and tested here, as well as the Sidewinder and Phoenix missiles. The launch vehicle engines tested last night will soon take cargo, and eventually crew, to the International Space Station. Falcon 9 represents the only medium to heavy lift rocket that is 100 percent Made in America and with this vehicleâ"SpaceX will bring leadership in launch back to the US. The leadership role is currently held by former Soviet Republics, France, and China. http://www.wacotrib.com/blogs/content/shared-gen/blogs/communities/breakingnews/entries/2008/11/23/spacex_issues_statement_on_con.html
This space available.
You realize most of the Hiroshima survivors weren't even inside refrigerators, right? Just curious why that scene seems so unbelievable to so many people. There are people around today who were close enough to the blast that it destroyed the building they were in. They had to be dug out of the rubble of the building that collapsed around them. But they're still alive and kicking in 2008. Unless you're literally at ground zero, surviving a nuclear blast, particular the old A-bombs, really was pretty much as simple as ducking and finding cover. There are over 50,000 alive today who didn't even do that in Hiroshima and are still around...
"Convictions are more dangerous enemies of truth than lies."
Nuclear weapons are not nearly as "unsurvivable" as many people apparently believe. You might be interested to know that about 7% of the people at Hiroshima who were within 1000 feet of the blast site survived. I'm sure Indy has beaten worse odds before :)