dnkanigan – Page 3 – Ares I-X Test Flight

The Ultimate Parachute Test

Jennifer Morcone Stanfield, a NASA Public Affairs Officer, wrote this great piece about the parachute system on Ares I-X.

How do you stop a 200,000-pound solid rocket motor from ending up at the bottom on the Atlantic Ocean? With the biggest, strongest rocket parachutes ever built of course! Right now, these massive parachutes are snuggly packed in the forward section of the Ares I-X rocket’s first stage, awaiting their debut performance. The Ares I-X flight will be the first full flight test of the Ares I parachute system.

NASA, its partners have successfully tested each element of the parachute system. In fact, over the last three years, the team has conducted three pilot, two drogue, three single main, and one main cluster parachute drop tests at Yuma Proving Ground in Yuma, Az.

But Ares I-X will be the best test of the whole kit and caboodle because of the unique flight profile.

The Ares deceleration system consists of three types of parachutes: (1) a small pilot chute, which pulls out the drogue chute; (2) a 68-foot diameter drogue chute and (3) three 150-foot diameter main parachutes. Here’s how the sequence goes:

The Ares I-X first stage separates from the upper stage at 124 seconds into the test flight, at an altitude of 130,000 feet. The vehicle’s four tumble motors then fire to slow the first stage for its return trip to Earth and eventual recovery. At an altitude of about 15,000-feet the nose cone is jettisoned, immediately deploying the pilot parachute. The pilot chute will in turn deploy the 68-foot drogue parachute, which is the workhorse of the system and will re-orient the booster to vertical and slow it to acceptable conditions for main parachute deployment. At about 4,000 feet, the separation at the base of the forward skirt extension occurs, pulling out the three 150-foot diameter main chutes packed within. These majestic red, white and blue canopies slow the booster even more, carrying it gently to splashdown.

“The velocity and re-entry environments we’ll see on Ares I-X are bit less than Ares I, but we will get a great deal of data to help us refine the final flight hardware designs,” said King. “We can’t wait to see our giant parachutes off the coast of Florida.”

How to Stack a Rocket

During the months of the assembly operations, the Ares I-X team stuck a camera in the Vehicle Assembly Building to record everything.

The result…10 months of hard work stuffed into 5 minutes and 45 seconds. Watch the video on YouTube

Enjoy!!

Message from Ares I-X Mission Manager — Bob Ess

Labor Day is behind us and the I-X team is now in the “home stretch” for launch. We are on track for October 31st, which is only 51 days from now. Over the last few weeks a substantial amount of work has been completed on I-X. On August 13th, we completed stacking and final mechanical assembly of the 327-foot rocket, making it the tallest rocket in the world! Since that time, the team has been routing electrical cables throughout the interior of the Upper Stage Simulator as well as on the outside of the solid rocket motor. In addition, final electronic components have been installed including rate gyros and a test version of the flight computer. The vehicle is covered in over 700 special sensors (Development Flight Instrumentation or DFI) which have been painstakingly tested, one by one to assure their function during the launch.

The next major milestone is the Vehicle Power Up, which began on September 11 and will continue through the 15th. This is the first time that either ground power or on-board battery power is applied to the electronics as a system installed into the vehicle. This is a significant step forward toward launch. After a successful power up, the team has several weeks of integrated avionics testing where each system and component will be tested and the vehicle will be run through many simulated mission profiles to ensure everything is go for flight.

In parallel with all these activities on the vehicle, a lot of work is occurring at launch pad 39-B. The vehicle stabilization system is being installed to the Fixed Service Structure (FSS). This will hold the vehicle in place during the launch preparation at the pad and will be removed approximately 1-2 hours prior to liftoff. Other modifications to the pad, like new cooling capability for the avionics during ground test, are complete and awaiting the arrival of the rocket.

The launch team has already been training for the launch process. Several simulations have occurred to give the launch team experience on how to handle any problems during the countdown with this unique vehicle. Simulations will continue into October with each simulation increasing in fidelity and details of launch process and possible anomalies.

The Ares I-X team is getting really close to completing this historic launch. A huge amount of knowledge and data will be gained from this flight that will help NASA develop and refine future launch vehicles. This data applies to all future launch vehicles especially those that are an evolution of current launch vehicle technology and capability.

Since the inception of this project in 2006, the NASA team along with its contractors have attempted and succeeded to do something unprecedented. This flight is truly historic not just in the amount of data that will be received but in the benefits already realized. Five different NASA centers are working hand in hand to create this new system. We have made changes in how we use computer models for key aspects of such a launch vehicle and NASA, as a whole, has become more tightly integrated into one productive group that has shown it can address and solve any technical problem that comes our way.

Keep a look out for more information on I-X: The First Flight of a New Era.

— Bob Ess
Ares I-X Manager

Practice Makes Perfect

The Ares I-X Launch Team spent the day in the firing room preparing for the upcoming launch. The team conducted a simulation of the last 50 minutes in the launch countdown.

Now this is no walk in the park simulation. The team was thrown different scenarios and issues that could come up during the actual launch countdown, including issues that could ultimately cause a launch delay. In fact, this specific set of simulations was focused on problems that the sim (simulation) team knew would prevent a launch in order to give the I-X launch team practice on handling emergency and stressful situations. All of this is designed to identify any problems in the countdown planning process and any vague areas in the launch commit criteria while stressing the team beyond what we ever expect to see on a real launch day. Sounds like fun, huh?

The simulation required support from Kennedy’s Firing Room 1, Cape Canaveral Air Force Station’s Hangar AE, the Software Integration Lab, or SIL, and team members from multiple NASA Centers. This was the first simulation with the entire team. The next simulation is planned for the end of September and will include the Launch Advisory Management Team.

Rock-a-bye Rocket

Even though the rocket is now stacked and sitting on the mobile launch platform in Kennedy Space Center’s VAB, there is still a lot of testing and prep work to be done before it’s ready to roll out to the pad. Over the weekend (Aug. 29-30) the rocket underwent two days of modal testing to make sure it’s ready to stand up to the environments it’s about to find itself in.

The testing required a total of 44 accelerometers — a device that measures movement — to be installed on the flight test vehicle. And to put those on the vehicle it took more than 27,000 feet of cable. That’s more than 5 miles!

During the testing, vibrations were mechanically introduced into the rocket by four hydraulic shakers simulating the same kind of vibrations expected during flight so the effects could be monitored. A sway of the vehicle was then manually introduced (with a little help from Mission Manager, Bob Ess and Deputy Mission Manager Steve Davis) to create a lateral, back and forth motion so the team could measure how the rocket reacts.

Here’s a little fast-motion clip of Steve and Bob rocking the rocket (Flickr).

This part of the testing was important because it simulated the conditions the rocket could experience as it rolls out to Kennedy’s Launch Pad 39B, the wind conditions at the launch pad before it launches, and what it would experience during flight at first stage ignition.

NASA did some similar testing years ago on the Saturn V at Kennedy Space Center in the 60s. For those tests a group of people sat up on a platform and rocked the vehicle back and forth with their sneakered feet from one side, while another group of people pulled on the rocket with ropes from the other side. The group appropriately named it the “Tennis Shoe Test.”

The completion of the Ares I-X modal testing is an important step for the mission because it clears the way for next week’s Integrated Vehicle Power Application or systems power up test, which will be the first time that all of the electrical systems, control boxes and sensors will be turned on together and powered up.

Really Taking Shape Now

Yesterday, yet another portion of the Ares I-X rocket was stacked on the Mobile Launch Platform in Kennedy’s Vehicle Assembly Building. Now that super stack 1 is up and on, the 327-foot rocket is more than half way assembled and the team is getting excited as they watch it take shape in High Bay 3.

Super stack 1 is composed of the fifth segment simulator, forward skirt, forward skirt extension, frustum and interstages 1 and 2. It also includes two internal elements – the roll control system and the first stage avionics module – as well as the parachute system housed in the forward skirt extension. The team used a massive overhead crane, specially adapted for I-X use, to place it on top of the forward motor segment.

Over the next month, four more super stacks with the final pieces of hardware (including the simulated crew module and launch abort system) will be mated, finishing off the stacking operations for the rocket. So, in about a month, NASA is going to be able to show off one of the biggest rockets the world has ever seen!

Ares I-X is scheduled to roll out to launch complex 39B just four days prior to its targeted liftoff of October 31.

Aft Center Section is Up…Over…and On

With its telltale “Z” stripe showing, the aft center section of the Ares I-X first stage booster is hoisted into place. Using a 325-ton capacity crane, the aft center is being lifted so it can be joined to the aft section already in place on mobile launch platform 1.

Last week the aft section was placed on MLP 1 and locked down by four huge bolts — each of which has 750,000 pounds of tension in them when torqued down. The 100 foot horizontal and 90 foot vertical journey from the center transfer aisle of the VAB into VAB high bay 3 takes many hours due to the methodical nature of handling and moving solid rocket motor segments loaded with hundreds of tons of explosive propellant.

Once the aft center section is in place, the forward center section will soon be brought over and finally the forward section will be joined to the other three. Once we have all 4 sections stacked, we will be ready for the first non-rocket motor section called Super Stack 1.

Vibrations and Loads

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!

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