What a Space Shuttle Launch REALLY Sounded Like

When I attended my first space shuttle launch, the most amazing thing about the whole launch experience may have been the sound. Being there at Kennedy Space Center is nothing like seeing it on television. When the sound waves travel across the 5.6 km (3.5 miles) from the launchpad to the KSC press site, the noise and sound just absolutely overwhelm and engulf you. You don’t only hear and see a space shuttle launch, you *feel* it! I heard astronaut Steve Robinson describe it as “it seems the air just isn’t big enough for the sound.” That sums it up pretty well.

Each launch I attended, I tried to record the crackling and popping of the rockets burning, but my audio equipment was just overwhelmed and the sound was completely distorted. This video is fairly close to what the sound is like, especially if you use a good sound system and turn it up, as the video’s creator, indiegun suggests. He used dozens of different video sources and several audio versions of shuttle launches mixed together to mimic as close to the real experience as he could.
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Psychedelics in the Sky: NASA Launches 5 Rockets in 5 Minutes

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After several days of delays due to weather and technical issues, NASA has now successfully launched five suborbital sounding rockets in five minutes from the Wallops Flight Facility in Virginia as part of a study of the upper level jet stream.

The first rocket was launched at 4:58 a.m. EDT and each subsequent rocket was launched 80 seconds apart.

Each of the rockets released a chemical tracer that created psychedelic-looking clouds at the edge of space, which were reported to be seen from as far south as Wilmington, N.C.; west to Charlestown, W. Va.; and north to Buffalo, N.Y.

The above image was taken from one of the official viewing sites by a NASA photographer; below is an image taken by John Anton from New Jersey, as well as more images from NASA, the video showing all the launches and time-lapse video from twolf1 on Vimeo.

Chemical tracers from the ATREX mission as seen from New Jersey in the US. Credit and copyright: John Anton.

The Anomalous Transport Rocket Experiment (ATREX) is a Heliophysics sounding rocket mission that gathered information to better understand the process responsible for the high-altitude jet stream located 95-105 km (60 to 65 miles) above the surface of the Earth.

Sounding rockets released chemical tracers that created strange milky, white clouds at the edge of space. Credit: NASA Wallops

Scientists from the mission had viewing sites at three locations: the launch site in Virginia, the Rutgers Marine Field Station in Tuckerton, N.J., and the U.S. Army Corps of Engineers at Duck, N.C. Clear skies at all three locations were a prerequisite for the rockets to be launched.

The sounding rockets were two Terrier-Improved Malemutes , two Terrier-Improved Orions and one Terrier-Oriole.

Chemical tracers from ATREX rockets launched from NASA’s Wallops Flight Facility in Virginia from twolf1 on Vimeo.

The map of the mid-Atlantic region of the U.S. shows the projected area where the rockets may be visible while the motors are burning through flight. It also shows the flight profile of each of the five rockets. Credit: NASA/Wallops

The high-altitude jet stream is higher than the one commonly reported in weather forecasts. The winds found in this upper jet stream typically have speeds of 320 to well over 480 km/hr (200 to over 300 mph) and create rapid transport from the Earth’s mid latitudes to the polar regions. This jet stream is located in the same region where strong electrical currents occur in the ionosphere. It is therefore a region with a lot of electrical turbulence, of the type that can adversely affect satellite and radio communications.

Not only did the rockets release the chemical tracers to allow scientists and the public to “see” the winds in space, but two of the rockets had instrumented payloads to measure the pressure and temperature in the atmosphere at the height of the high-speed winds. NASA will release more information on the outcome of the experiment after scientists have had time to review the data.

See a slideshow of images of the launches on Flickr from NASA

Armadillo Aerospace Rocket Destroyed

Saturday was a perfect day for flying, so we went out to the 100 acres for a boosted hop. We had high expectations for success, since the vehicle had been operating perfectly on all tests so far.

After we loaded up the propellant and pressurized the vehicle, we ran into a problem. When I opened it up to 20% throttle for the warmup it looked like it cleared up fine, but the telemetry was only reading 100C, as if the hot pack hadn?t started heating. We were a long way from the vehicle, so we couldn?t really tell what was going on. I gave it a bunch of slugs of propellant until it finally started going up in temperature properly, but we had blown a lot of propellant out on the ground. Too much.

It finally reached operating temperature and we launched. We had only been operating this engine at hover thrust levels, so we had been a little concerned that it might be rough at full throttle. It was. It flew fine through the roughness, but when it started to throttle down after the two second boost to a 0.5 G positive acceleration level for the stabilization phase, the rough pulses kept passing both above and below the desired acceleration, keeping the engine from throttling down at full speed, resulting in it going a lot higher than intended (just under 600 feet high). It did finally get out of the rough stability zone into clear stabilization, but a couple seconds later, everything got quiet. It ran out of propellant.

It had not hit apogee yet, so the unstable vehicle immediately started rotating, hitting about 50 degrees / second. If the vehicle had been past apogee when it ran out, it probably would have just dropped feet first.

We had telemetry all the way to the time of impact, which matched the video perfectly, landing eight meters from the launch point. The vehicle hit the ground basically sideways, a little tail first. The bottom manway flange broke off the tank, and the 450 pound tank with 180 psi pressure still in it got punted about 200 yards away by the gas release. $35,000 of rocket is now a whole lot of primo Armadillo Aerospace Droppings. There are a few pipe fittings that survived, but that?s about it. Amazingly, even though the on-board camera was destroyed, the tape did survive with only some scuffed sections. It?s a good thing Doom 3 is selling very well?

From analyzing the telemetry (integrating the chamber pressure during the flight), it looks like it wasted two thirds of the propellant on the warmup. If it had lifted off with a normal warmup, it would have landed ok even with the rough throttling, but we would have been in violation of the 15 second burn time limit by the time it landed. There was twice as much propellant loaded as this flight should have required, which I thought was enough to cover any off-nominal conditions, but we obviously should have scrubbed when the warmup didn?t catch after the second or third try. We are going to look into getting a continuous capacitive level sensor next time so we can have a firm no-go line for liftoff. If anyone knows of a peroxide compatible (316 SS / Teflon / viton / eetc) capacitive sensor that runs off of 12v or 5v DC and can handle 300 psi (we may be willing to run past rated pressure if nexessary), let me know. Ideally we would want a 5V or 10V analog out, but we could live with a current sensor, or (with some begrudging) a serial port. We would like to mount it on the bottom of the tank instead of the conventional top location, but we don?t think that will be a problem.

The failure did give us some demonstration data that we always sort of wanted to get (but not that bad). The vehicle is absolutely, positively, NOT going to continue flying nose first when it loses active control. This should be blatantly obvious from the CG, but we had a WSMR engineer pushing us towards a NASA consultant to prove it. When it fails in the air, it just drops like a rock, landing very near the launch site. Rupturing a fiberglass tank doesn?t produce shrapnel, but it does drop kick the tank pretty good. This looked pretty close to an optimal 45 degree launch angle for the tank, so we have a pretty good idea what our safe distances should be.

We probably would have been able to save the vehicle if we had a rocket drawn parachute on board, but we are trying to have a pyro-free vehicle. A pneumatic drogue cannon might have been able to deploy a chute fast enough, but it would be a lot more debatable.

We cut the engine open with the plasma cutter to do a post-mortem, and found what had been causing the engine issues. The combination of the bottom catalyst retaining plate bowing down because it was only welded on the bottom and some catalyst escaping both out the bottom and some out the top (the top screen was burned through in a couple places) left the bottom catalyst not even completely covering the diameter of the engine. When we had the nozzle and cold pack cut off and the engine on its side, you could see right through the hot pack at the top. This explains the apparently clear exhaust at the start while the thermocouple was still reading only 100C, because the thermocouple was fairly short (we used to use a longer one, but the bowing of the retaining plate forced us to use a shorter one so we could still insert it) so it was in a stream around the edges that bypassed most or all of the hot pack catalyst (driving down the highway probably also settled the catalyst on the opposite side from the sensors), while much of the main flow was still being burned. The loosening catalyst is also almost certainly why this engine ?got rough? after we had been using it for a while.

The support plate bowing can be fixed by either making a full depth angle on the sides of the plate so the weld gets full side coverage, or actually weld the plate between two chamber sections, instead of inside a single chamber section. We are making new plates that are made with 1300 quarter inch holes instead of large water jet cut squares that are bridged by screens. This will let us completely avoid the screens altogether, and we are also going to tie the top and bottom plates around the hot pack together by putting quarter inch bolts through some of the quarter inch holes, and welding them together as a unit with the catalyst in between. This should fix the engine behavior.

Everything else operated perfectly, so we still feel good about the general configuration, but we have a number of improvements for robustness and operability that we will be making in the next vehicle we put together. A couple of the necessary items are fairly long lead times, so we are probably grounded for five weeks.

Original Source: Armadillo Aerospace Status Report