Tag Archives: first stage

Introducing 327 Feet of Ares I-X Rocket!

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Now this is something you’ve really got to see!

For the first time in more than 25 years, a new space vehicle is assembled and rarin’ to go in KSC’s Vehicle Assembly Building. Standing more than 320 feet tall, the rocket is almost twice as tall as a shuttle stack.

A crane hoisted the simulator launch abort system tower off the floor and placed it on top of the Ares I-X to complete he rocket stack.

It’s obviously a huge milestone! Now you can really get a feel for the scope of the vehicle.


The test rocket has been assembled on the top of a modified mobile launcher that used to be used by the shuttle. 

Now that it is assembled, there will be extensive tests run on all the systems, including the set of complex instruments that will measure the rocket’s movements as it launches and the first stage separates.

These tests will include a process called “modal testing,” which will shake the stack slightly to test stiffness of the rocket including the pinned and bolted joints and make sure the rocket can handle the strain of launch and ascent. While those tests are conducted, a team of about 30 launch controllers also will practice their roles in the firing room preparing for its targeted launch in late October.

Vibrations and Loads

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It may be pretty obvious, but it’s worth noting that one of the main purposes of a flight test is to do a little trailblazing. We can and should test processes and procedures as early in a program as possible so we can identify any areas for concern and target problem spots that need some improvement. The more we build and fly, the more we learn. As a flight test, Ares I-X is doing that exact thing for the Ares I rocket.

One aspect of rocket building that we are paying special attention to lately is vibration. Rockets vibrate a lot. In the case of Ares I-X, the vibrations come from several sources. Among them are the vibration and sound waves caused by the lift off of the rocket, the burning of rocket propellant and the act of plowing through the atmosphere at over four times the speed of sound.

The vibration that is produced by the burning of the solid rocket propellant in the first stage booster is called thrust oscillation. These vibrations — or oscillations — come in the form of waves, which travel up and down the length of the rocket like a musical note through an organ pipe. One of the biggest challenges in any rocket design is developing avionics (aviation electronics) that can function in this vibrating environment.

Vibration is not just a rocket issue, though. All electronic hardware is tested for its ability to handle shock and vibration. An MP3 player, for example, has to be tested for its ability to handle the vibrations from someone walking or jogging while holding it, placing it on a countertop, or accidentally dropping it on the floor. However, compared to the workout that Ares I-X’s avionics receive, your MP3 player has got it easy. Imagine shaking that MP3 player inside an automatic paint can shaker for two minutes while continuing to play your favorite tunes. That’s kind of what the electronics of the I-X are up against.

Two of the most important sets of electronics on Ares I-X are the thrust vector control (TVC) system, which steers the rocket, and the flight termination system (FTS), which is used to “self destruct” the rocket if it veers off its proper flight path.

Recently, NASA engineers at Langley Research Center upgraded to a new, higher-precision computer model, which allowed them to more closely examine the vibration environments on Ares I-X. With this more precise model, they observed that some areas of the rocket had vibration levels — called “G-loads” or just “loads” in engineer-speak — that were slightly higher than the levels the TVC and FTS were initially tested to handle.

How much is “slightly?” Well, Langley’s engineers are still examining the computer models to get the full answer, but right now the observed vibration levels are measured in hundredths of a gravity (or “G”). That would be like giving the automatic paint shaker one extra shake every minute — you wouldn’t notice the difference, but your MP3 player might.

The computer models have found that the biggest effects of the thrust oscillation on Ares I-X come between 70 and 90 seconds into the flight, when the rocket is about three fourths of the way through its ascent. Before 70 seconds and after 90 seconds the vibration levels are fine, but for those 20 seconds we haven’t fully verified that we can still steer the rocket with the TVC or send the signal to self-destruct the rocket and end the flight with the FTS if it veers away from its projected path.

So that’s the challenge the Ares I-X team is facing right now. Fortunately, we have several options for handling the situation, and the I-X team is looking at all of them to determine the best way forward:

  • First, the team is analyzing the new vibration models more closely to make sure that the components really do exceed their limits, and if so, by how much.
  • Next, if the team determines that the vibrations do exceed the design limits of the TVC or FTS, test engineers could re-test the components to operate at the higher vibration loads. If the components pass the re-testing, the stacking and assembly of the rocket will continue as planned.
  • However, if the test team finds that the avionics could still have problems at the higher vibration levels, they may need to make some modifications to the vehicle like adding additional support structures to dampen the vibrations or isolate the hardware from the vibrations’ effects.

Since the beginning of the I-X mission, NASA has worked very closely with the Air Force’s 45th Space Wing’s Range Safety team, which controls the range at Kennedy Space Center to make sure that every precaution is taken to ensure a safe launch and a safe flight. The 45th Space Wing will continue to work alongside the I-X team to evaluate the situation and make sure that the best decision is made.

The bottom line is that we’re not launching anything until it’s deemed safe by NASA and the U.S. Air Force, even if it takes a little longer to get it right. We’re all excited about watching Ares I-X take flight later this year, but really, we might end up learning just as much from these steps along the way as we do on launch day.

Supersize Me!

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The Super Stack 1 assembly is now complete with the mating (stacking) of the forward assembly to the fifth segment simulator. Stack one is made up of eight individual pieces: interstages 1 and 2, the frustum, the forward skirt extension, the forward skirt and the aft, center and forward segments of the fifth segment simulator. It also includes two internal elements, the roll control system and the first stage avionics module.

All five super stack assemblies are now complete in High Bay 4 of the VAB and are ready for stacking on the mobile launcher platform in High Bay 3 later this month.

Just so you know, the reason the rocket is separated into these super stacks has to do with the height and weight of each piece for crane loads during lifting operations.

Super Stack 2: Upper Stage Simulator “Tuna Cans” segment 1

Super Stack 3: Upper Stage Simulator “Tuna Cans” segments 2, 3, 4, 5

Super Stack 4: Upper Stage Simulator “Tuna Cans” segments, 6, 7

Super Stack 5: Spacecraft Adapter, Service Module, Crew Module and Launch Abort System

The Last Piece of The Rocket Has Arrived!

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The final piece of the Ares I-X rocket arrived at KSC on Thursday. The first stage segments trekked their way across the country (2,917 miles!) from ATK in Utah to KSC in Florida. They came by rail car and pulled in Thursday afternoon.

This is a big deal because the motor segments are the last piece of major hardware to ship. Now with the major hardware elements at the launch site, we can really get into stacking and watch the rocket take shape.

These motor segments that we’re using for the first stage are from the space shuttle’s inventory — that is they were originally built for the shuttle. Ares I-X made some modifications and added some new components to make them work for the flight test.

The first stage booster packs a punch too. It can generate 3.3 million pounds of thrust, and we’ll need every bit of that to launch the rocket. The first stage will give Ares I-X it’s lift-off capability and power it through the first 120 seconds of flight. When the motor is spent, it will separate and parachute back to Earth and be recovered and towed back to land to be reused.

First Stage Segments Are on the Move

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The first stage segments are just about ready to go. They have a long trip ahead of them from first stage contractor ATK’s facilities in Promontory, Utah to the launch site at Kennedy Space Center in Florida.

Last week, using specialty transporters, ATK moved the Center Aft Segment to a holding facility where it will be housed in preparation for the cross-country trek via railcar. Some one described these transporters as looking like something out of the Transformers movie and I don’t think that’s too far off. They are impressive looking vehicles.

That big black line you see running diagonally down the side is called a Z-stripe. The Z-stripe is a 24-inch wide stripe painted on the first stage motor segments that wraps from the top of the motor to the bottom.  The main purpose of the Z-stripe is to provide a way for the I-X team to determine the roll attitude and rate from footage recorded by cameras on the ground. That footage serves as a backup to on-board data gathered during the flight.  The Z-stripe will also provide confirmation that the rocket rolled 90° shortly after lift-off from the pad like it is supposed to. Measurement from watching the Z-stripe could be very helpful in the case that the flight goes differently than expected.

We’re expecting to ship the motor segments next month. They are the last few pieces of hardware to ship, so once they make it down to KSC, we’ll be ready to start putting the rocket together.