Ares I – Page 2 – Constellation

Ares Motor on the Move

The first of five segments for the Ares I development motor (DM-1) was moved April 16 from ATK Space System’s production facility in Promontory, Utah, to the nearby test stand, in preparation for the first ground test, targeted for August. This next generation of solid rocket motor will be used to launch humans on future missions to the International Space Station, the moon, Mars and beyond.

Manufactured by ATK – prime contractor for the Ares I first stage – the motor is similar to the Reusable Solid Rocket Booster (RSRB) currently used by the Space Shuttle, although the new motor is one segment longer (five segments instead of four) and there have been modifications to accommodate the Ares mission objectives. Following ATK’s usual manufacturing procedure, the segments were cast and then went through a complete X-ray inspection.

The moving of segments to the test area will continue at a rate of one per week until the final segment arrives May 12. The week between segments allows for insertion into the test stand and assembly as each piece arrives.

The critical forward segment, which contains the propellant fins and igniter, took the longest to manufacture and was the first to arrive at the test stand. The DM-1 motor will be assembled there from the top down.

The forward segment is designed with “fins” or slots in the propellant that provide additional surface area for burning more of the solid fuel. This creates more power, or thrust, during launch. The Ares first stage team has added a twelfth fin as opposed to the eleven fins in the shuttle’s RSRB and made the fin area three-and-a-half feet longer. The fins are cast in the propellant by using a mold during the casting process.

When the historic DM-1 booster undergoes ground testing later this year, it will be the first full-scale booster test of the new Ares I crew launch vehicle.

Engineers Review Solutions to Thrust Oscillation on Ares I

This week, engineers from across NASA and partner contractors gathered at Marshall Space Flight Center to analyze designs to minimize vibrations in the Ares I rocket. During this three-day meeting of the minds, participants showcased tremendous progress toward understanding the physics of thrust oscillation, updates to several candidate mitigation solutions, and results from early subscale testing of candidate hardware. This was not a decision-making session, but an opportunity for engineers and managers to scrutinize proposed solutions.

Thrust oscillation may be felt for a few seconds at the end of first-stage powered flight. Also called “resonant burning,” thrust oscillation is a phenomenon in all solid propellant rockets forcing vibrations through the entire structure, in the case of Ares I, that includes the Orion crew module.

To date, several promising mitigating systems have been identified to counteract vibrations stemming from thrust oscillations. Two primary options are actively under development:

Isolators:
Isolators are C-shaped springs that could be placed between the Ares I frustum and interstage to “detune” the vehicle resulting in less vibration for the crew while maintaining vehicle control stability. The design is based on an existing “soft-ride” technology developed by CSA Engineering, Mountain View, Calif. “Soft ride” technology, which has flown on 17 spacecraft, has been typically placed inside the payload shroud to protect payloads from oscillations. The current Ares design incorporates a ring of 136 C-shaped springs and attach hardware into an isolator module which measures 18.5 inches in height. ATK Launch Systems, located near Brigham City, Utah, is the Ares I prime contractor and is working aggressively with CSA Engineering to mature the isolator design. Moving forward, engineering teams will continue to evaluate the performance of the C-shaped springs and supporting hardware. Engineering design units have been tested on a “shaker stand” which simulates the thrust oscillation loads and demonstrated functionality and effectiveness of this system.

Tuned Oscillation Arrays:
An earlier active mitigation concept called Reaction Mass Actuators (RMA), has matured into a passive solution known as Tuned Oscillating Arrays (TOA). This system will be mounted inside the first stage aft skirt and includes an array of boxes that contain masses suspended on springs which absorb or soak up the vibration oscillation produced during first stage flight. Analysis of the aft skirt has indicated that the existing skirt design can support the TOA approach. Following the recent STS-119 shuttle mission, engineers conducted a fit check with TOA volume simulators and found the solution to be feasible in the existing aft skirt design. Next steps include finalizing bracket concepts to connect TOA boxes to the aft skirt and examining handling processes and equipment needed for ground support. The active RMA concept, which includes powered springs that actively cancel out the vibration, is on hold but available for restart if required later.

Two other alternative thrust oscillation strategies under study as risk mitigation to the baseline include:

A “dual plane” solution:
A dual plane solution would employ two rings of isolators, one located at the interstage/frustum interface and another between Orion and the Ares upper stage. Having redundancy of isolator rings may provide increased “detuning” capability to ensure the Orion does not respond to the oscillations of the first stage motor.

LOX damper:
Engineers are also evaluating a concept called a LOX damper, which uses the fundamental physical properties of liquids to leverage the kinetic energy in the movement of the existing liquid oxygen in the upper stage tank to dampen out vibrations. The devices, installed within the liquid oxygen tank, can engage the mass of the liquid propellant to generate momentum in the fluid itself to counter the vehicle acoustic response and disrupt oscillation. Engineers are evaluating the effectiveness and applicability of this design.

Data analysis:
In addition to discussing specific design solutions, the thrust oscillation team is pouring over existing ground and new flight test data captured from recent shuttle missions STS-126 and STS-119. During recent shuttle flights, sensors placed on both ATK-produced solid rocket boosters measured pressure oscillations, in addition to vibration measurements, on crew seats. Measurements are helping engineers anticipate the magnitude of thrust oscillations forces that may be expected on future Ares I flights.

NASA engineers and astronauts are also evaluating crew situational awareness under various vibration conditions in a simulator at the Ames Research Center. NASA is working to set the final requirements for acceptable crew vibrations – currently a 0.25g requirement that was developed during the Gemini era.

Next steps:
Testing of the isolators and TOA candidate mitigation hardware will march forward. NASA teams will capture additional data from future shuttle flights and from the upcoming test flight of Ares I-X to better understand the risk to the Ares I vehicle and the Orion capsule. Considering all information, NASA will finalize vehicle designs in a thrust oscillation preliminary design review which will define which system, or combination of systems, works best to minimize vibrations on the Ares I vehicle.

Where Things Stand with Constellation

Much has been said recently regarding the cost and schedule related to NASA’s successor program to the Space Shuttle. However, this is a subject where considerably more heat than light has been generated, so let’s review the bidding as objectively as possible.

First, some facts: NASA’s commitment has been and continues to be to achieve the first human launch of Orion by March 2015. We see that as eminently achievable, but it’s not a guarantee – there is no such thing in any large scale development program and especially for one where the available funding is never known more than one year in advance.

While there has been moderate growth relative to early cost estimates, these increases are contained within the projected budget profile to which the agency has worked to for the last three years. The development cost for achieving the first crewed flight today is roughly $30 billion, far short of estimates which have been recently bandied about.

How We Got Here

The Constellation Program, now in its fourth year, has nearly completed its ‘formulation’ phase – this is the phase in which concepts are developed, capabilities are defined, requirements are written, and contracts are established with industry.

When the program began, one of the many constraints it was called upon to honor was a ‘go as you pay’ plan – that is, the pace of the program would be dictated largely by the share of NASA’s annual budget that human spaceflight has historically been allocated.

Based on that constraint, it was always recognized that funding for a new development program would be exceedingly tight in the years 2008 thru 2010.

A second constraint, the key to achieving our exploration goals beyond low Earth orbit, was to make our early investments in Orion and Ares I so as to ensure that they could support missions to the moon, the near-Earth asteroids, and Mars, while nonetheless providing the capability to service the International Space Station

A third constraint embodied in legislative guidance was to use as much shuttle infrastructure and workforce as makes sense in the design of NASA’s new human spaceflight architecture.

All of this was in compliance with national policy. That policy, which was born out of the findings of the Columbia accident, started with a ‘vision’ from the Executive Branch in 2004, and then codified in two Congressional authorization acts in 2005 and 2008.

An additional desire (regrettably, never a policy mandate) was to do whatever possible to ‘close the gap’ between the last shuttle flight and the start of Constellation launches from KSC.

In short, Constellation is not ‘NASA’s plan’ – it is the manifestation of national policy.

Moreover, Orion and Ares I are not standalone products – the Constellation Program is a collection of seven product lines to conduct operations in and beyond Low Earth Orbit… servicing the ISS, returning U.S. astronauts to the Moon, and enabling exploration beyond – to Mars, Near Earth Asteroids, or other destinations in the solar system. This entire range of product lines encompasses the Constellation architecture.

So with these constraints, and many more, NASA’s Constellation team has executed this early phase – called ‘formulation’ – at historically low cost for a human spaceflight development program. Compared to Apollo, and to Shuttle, and to Space Station, Constellation has been markedly leaner in its efforts to date.

So Why Can’t Orion Fly Sooner?

As we have openly discussed, it is true that inside NASA we challenged our team during this ‘formulation’ phase of Constellation to do better than March of 2015 for flying Orion for the first time with a crew.

Our earliest plans had the first crewed mission targeted for September of 2013. While none of the cost estimates showed that date to be likely, we still felt that being internally aggressive would help us clarify what was really necessary to do the job. In that respect, as a program management strategy, it has succeeded.

It is also true that over the last year, as we approached the end of this formative period, we have adjusted our internal schedules to align with the reasonable projection of our ever-improving cost estimates.

We have thus gained a level of understanding of the ‘work to go’ that is very rich in detail, and a depth in understanding of what each of our requirements costs in time and money – perhaps as well as NASA has ever done. I will leave that to others to judge, but I’m quite proud of what we have been able to achieve.

It is simply a matter of money at this point, not technology. Further, it is not merely a matter of total cost, but also of the time-phasing of when the money becomes available.

Of ‘Unk-Unks’ and Schedules

We have been asked consistently for the last three years ‘what would it take to fly as early as possible’? Study after study of that question has revealed roughly the same answer – not more money, but money earlier, is the key to flying sooner, more confidently, and ultimately with the smallest amount of delay due to ‘problems’.

This is simply because, with sufficient early funding, engineers can investigate the riskiest parts of an emerging design for a spacecraft system or a rocket component and discover hidden problems early, before the design is ‘locked down’.

We call these ‘unknown unknowns’ or unk-unks, and if discovered early they can be accounted for in the design before building the final vehicle or system.

If discovered too late, after the design is ‘locked down’, then there is considerable cost required to rework the design, while the rest of the team waits until it is fixed.

We have done as much early risk mitigation as we have been able to afford in parallel with actually doing the design. But we have been forced to defer or eliminate some of that work in order to remain within our 2009 and 2010 funding limits – which have themselves changed as a result of Administration and Congressional decisions.

So those unk-unk’s we should be discovering now are lying in wait for us, and are of concern as we formulate our plan for achieving a March 2015 first crewed Orion launch, let alone anything earlier.

Keys to Success

NASA’s plans and programs are strictly a reflection of national policy. If the policy is to ‘go to the Moon by 2020’ and ‘go as you pay’, we respond with ‘here is how we propose to do it and, as best we can gauge it, here is how much it will cost’.

A few keys to success – and they are nothing new to program and project managers in any industry – are:

· stable funding – don’t keep changing the money

· stable requirements – don’t keep changing the plan

· early investments to investigate the riskiest parts of a complex design such as a human spaceflight system will save billions in delays and overruns

· a clear vision of the desired outcome – help the team ‘see’ the end game

NASA has done what it said it would do, indeed what it has been directed to do under national policy.

We have a functioning successor program to the shuttle. It is employing and re-invigorating the NASA institution across all of its 10 centers in California, Mississippi, Virginia, Ohio, Florida, Texas, Alabama and New Mexico.

We are today producing detailed designs and preparing to perform flight testing this year from test facilities in New Mexico and a shuttle launch pad in Florida.

We have laid out a plan and architecture, not just to replace the space shuttle, but to take astronauts beyond Low Earth Orbit. Not only are the Orion spacecraft and Ares I rocket progressing well in their designs, but early concept work is proceeding on the heavy-lift Ares V rocket, which will be more powerful than Apollo’s Saturn V, and the Altair Lunar Lander.

Construction is progressing at the Kennedy Space Center on launch pads, processing facilities and even the factory where Orion will be assembled.

Large scale facilities are being renovated or built anew in Utah, California, Colorado, Ohio, Mississippi and Louisiana to fabricate and test the major components. And orders are being placed with high technology suppliers in most states of the union.

NASA’s Constellation Program is rejuvenating an agency and an industry.

NASA’s value lies in the trails that it blazes, the things we do that are hard, so that industry can follow and create new markets. Our role is to occupy the pinnacle of a $300B ‘space economy’ that generates products and services that bolster the nation’s broader economic productivity. We are doing so in a highly constrained ‘go as you pay’ environment, in parallel with meeting the nation’s commitment to completing the International Space Station, retiring the Space Shuttle, and mapping a course for human endeavor beyond our experience.

Contributed by Jeff Hanley, Constellation Program Manager

It's All About the Stars

What do the patches and pins that represent NASA’s Constellation Program and its projects symbolize? Most of you have seen the crew patches, similar to the shoulder patches worn by members of the military units, that are used to identify each NASA mission.

Today, many of NASA’s programs and projects have informally adopted emblems — and make them into patches — to build team pride and identification.

The Constellation emblem is intended to represent NASA’s effort to continue exploration from Earth to the Moon, Mars and beyond. According to Constellation patch designer Mike Okuda, the three crescents represent these three worlds, in order of distance, and in order of the increasing challenges that must be overcome to reach them. He says the crescents might also suggest worlds illuminated by the light of knowledge.

The emblem’s red vector suggests the outward direction of exploration, a symbol borrowed from the NASA agency insignia. Similarly, the dark blue background is deliberately suggests the NASA insignia. The 10 stars signify the 10 NASA centers working to return to the Moon.

Okuda says the outer equilateral triangle suggests simplicity and strength — the extraordinary engineering efforts it will take to achieve Constellation’s objectives.

The Orion crew exploration vehicle patch represents that project’s efforts to develop an advanced spacecraft that will take astronauts to the International Space Station, the Moon, and someday to Mars and beyond. The patch also employs the equilateral frame, a unifying element in all of Constellation’s patches. The blue sphere is represents Earth. The red flight path illustrates the first missions to the space station, but then it shoots outward to the three large stars, implying the Moon, Mars, and worlds beyond. Okuda says the three stars also evoke the belt in the constellation Orion, while the other 10 other stars, arranged to suggest the same constellation, represent NASA’s 10 centers.

The Ares launch vehicles patch illustrates the sheer power needed for a spacecraft to escape Earth’s gravity and reach for the stars. Okuda says the single bright star represents the launch vehicles, suggesting the dreams those vehicles will carry into the heavens. The light illuminates the crescent Earth, and once again, the 10 stars represent the NASA centers.

Okuda also designed the Altair lunar lander patch, which is based on the mission patch for the historic Apollo 11 moon landing. The eagle on the patch, of course, represents the United States. Eagle also was the name of the Apollo 11 Lunar Module, the first human-piloted spacecraft to land on the moon. To distinguish the project patch, the eagle faces in the opposite direction, since it represents humankind’s return to the moon.

On the patch, the eagle carries an olive branch to represent peaceful exploration of space. The 10 stars are arranged to represent the constellation Aquila, or the eagle, of which the brightest star is Altair, translated as “the flying one.” The “A” in the word “Altair” is based on NASA’s original mission patch for Project Apollo. According to Okuda, engineers working on Altair asked the eagle’s wing extend beyond the frame of the background triangle to signify their determination to use creative thinking to solve the many challenges they will face in such an ambitious effort.

Small Steps to a Great Adventure

If the greatest adventures begin with small steps, the Constellation Program took giant strides in 2008 and has more planned for 2009. Here is an excerpt from the year’s-end note, dated December 2008, Constellation Program Manager Jeff Hanley sent to his team.

All, as I type this I’m coming to the end of nearly a full week in our nation’s capitol, and here at the end of our third year as a team I owe you an update from 50,000 feet (sorry, 15 km). I think it’s important that our entire team have this context, so that we can together take on the challenges that 2009 will surely bring.

First, as I review the events of 2008, and the progress that we together have made across this agency team, I am truly proud of what you have accomplished — and you should be too. Today we have projects and hardware and software in nearly every phase of the lifecycle, from pre-formulation of our lunar surface strategy and the international partnerships that are already beginning to form, to formal formulation of the Ares V and Altair requirements, to completion of the program definition phase for Ares I, Orion, and their sister projects, to the testing of engine components and fabrication of flight test hardware for Pad Abort 1 and Ares I-X.

The program has built considerable momentum in the past 12 months and indeed over the last three years since we stood up as a team. We’ve done it for a fraction of the cost in people and resources compared to Apollo, shuttle and station through this phase. We’ve done it while the same supporting institutions execute our other two human spaceflight programs. We’ve done it with focus and resolve to transition shuttle workforce and assets to the new program in the smartest way possible. We’ve done it — done it all — with the Moon as our goal. “Design for lunar” has guided our every move, our every decision, within the bounds of what we can fiscally afford through these lean years until shuttle is retired.

I know you all have seen the public discourse regarding Ares and Orion and shuttle, and understandably such discourse can temper our resolve to push forward — if we let it. But, let’s review the bidding. First, we should remind ourselves, as we saw in intimate detail at last summer’s Lunar Capability Concept Review (arguably the finest such review the team has yet executed), that the Ares I/Ares V/Orion/Altair transportation system is highly integrated and keenly designed to open the lunar frontier to us in the years to come. Our driving requirements of going anywhere on the Moon, staying twice as long as Apollo in a sortie mode, sending twice as many crew members, and enabling their return at any time, must remain at the forefront of any consideration to alter the nation’s exploration launch architecture. I assure each of you that we are doing all we can to communicate this key aspect of our baseline plan — it is about much more than launching Orion to LEO (Low Earth Orbit).

The shuttle team, as you know, has performed a study of projected cost and decision points for extending the life of shuttle. I have not seen the report in its final form so I won’t comment on the interim version. But I will say — will reassure you — that Constellation’s needs, interests, and requirements were central to their deliberations, and we were partnered closely with the study team to provide the Constellation implications of any extension. It was a good effort and I am quite satisfied that any impacts to Constellation are well accounted for.

Somewhat in tandem, in October we kicked off our own special study led by Ralph Roe out of NESC (NASA Engineering and Safety Center) to look at options to accelerate Constellation to allow the first human flight to occur prior to our March 2015 commitment date. All of the deputy managers of our program and project offices participated, along with a substantial number of experienced contributors from outside the program. It took our most recent baseline plan — including budgets, schedules, technical content, risks and threats, and assessed achievability of three different acceleration cases to improve upon the March of 2015 commitment date, assuming of course that resources were added to do so. Ralph briefed the draft report to leadership at HQ (NASA Headquarters), and while it is still being finalized, the findings are not new — the upshot being, if you want to accelerate Ares I and Orion then significant new money must be added to the Constellation budget in FY09 and FY10. This is the same answer that we provided more than a year ago when asked what it would take to keep our September 2013 baseline with an adequate level of confidence.

And no wonder – if you look at a “traditional” funding profile for an aerospace program and compare it to the Constellation budget profile, the deficit in these early years is obvious. What it compels us to do, therefore, is defer some key work to later that would buy down considerable risk — flight and ground tests, manufacturing demos, test articles to investigate structural margins, engineering development units, buys of long lead parts, etc. This is where we are at today with our internal target of September 2014, compounded by very lean reserves in these same two years to deal with surprises.

We’re at where we’re at. In the weeks ahead we will proceed assuming no new money will be forthcoming to accelerate and we will instead move forward to adjust our plan to meet our March 2015 commitment. If a decision comes forward to accelerate by the April timeframe, an earlier date is still possible, but that gets less and less likely with each passing month.

Again, none of this should be a surprise — though some will feign shock and accuse us of overselling. But we have been very careful these three years to avoid that. We have consistently pointed out that our internal ‘work to’ dates were aggressive with this fiscal profile and what additional funding it would take to increase our confidence and ability to execute. These same realities have been reinforced by those who independently review us. Throughout we have applied common government and industry practices and methods for how projects and programs are funded and managed. We kept the option open to enable a more aggressive date as long as we reasonably could before last summer’s re-baselining. Two years of continuing resolutions haven’t helped, but we’ve worked around them to the best of our ability to keep moving forward.

Look at all you’ve accomplished in spite of that!!

All this is offered as context to further amplify what an amazing result — in spite of it all — that 2008 has produced. Constellation is not a paper program anymore. It is a full-fledged assault on the frontier, and if we keep the mission at the forefront of our sights then we can persevere. As the year draws to a close, we enjoy broad support in Congress, we have a vision that we’ve not only embraced but have strategically over the last three years codified in an exploration architecture with a broad range of capability to allow us to unlock first cis-lunar space and then the inner solar system in the years to come… and who knows what other missions these new tools might be employed for?

In the coming year, let’s continue to make history — one milestone at a time — as we celebrate those whose shoulders we stand upon more than a generation ago.

Ares: America's Rocket for Future Space Missions

How did NASA select the Ares family of rockets as America’s new space transportation system?

Since the 1980’s, NASA has evaluated thousands of studies relating to space transportation. It has been said we could “pave” the way to the moon with all the studies that have been conducted. These studies looked at thousands of combinations and variations of how to send humans beyond low Earth orbit, back to the moon and on to Mars.

NASA looked at a wide variety of launch concepts — from the Evolved Expendable Launch Vehicle (Atlas V, Delta IV), Space Shuttle (including Shuttle C, Direct type approaches and other solid and liquid rocket booster propelled systems) combinations, foreign systems and clean sheet designs.

The Exploration Systems Architecture Study (ESAS) was chartered in the spring of 2005 to recommend a fundamental architecture for supporting International Space Station, Lunar and Mars transportation.

Using data from previous and ongoing studies (several hundred vehicles), and consisting of a team of knowledgeable experts from inside and outside NASA, this study compared many launch and staging options for safety, effectiveness, performance, flexibility, risk and affordability.

ESAS concluded that NASA should adopt and pursue a Shuttle-derived architecture as the next-generation launch system, using a smaller vehicle for crew missions and a dedicated, heavy-lift launcher for cargo missions. This approach was selected due to several significant advantages, particularly safety, reliability and cost.

NASA continued to refine its launch recommendations post-ESAS. Since early 2006 NASA has made the following major modifications to the initial designs.

Upgraded from the shuttle’s four-segment reusable solid rocket booster design (RSRB) to a five-segment RSRB design — forming a common basis for Ares I and V Eliminated the space shuttle main engine (SSME) in favor of a newly designed J-2X engine for the Ares I upper stage. The Ares V upgraded from a five-segment RSRB with expendable SSME Core to a derivative of the Ares I 1st stage with a six-engine RS-68 Core and the J-2X engine for the earth departure stage (EDS).

Developing the new J-2X engine for both the Ares I upper stage and the Ares V Earth departure stage solves several potential problems including starting the SSME at altitude and the major expense of using it for the first stage engine. For additional cost savings Ares will use the expendable RS-68 engine which is “off the shelf” technology that meets both Department of Defense and NASA needs.

These combined changes represent a projected savings of over $5 billion in life cycle costs below the initial ESAS recommendations.

The shuttle heritage design offers years of proven flight concepts with a very strong technical and safety foundation for next-generation vehicle. Since ESAS, NASA has continued to assess options — over 1,700 to date. After a thorough analysis of all the exploration architecture requirements, other solutions were ultimately determined to be less safe, less reliable, and more costly than Ares I and Ares V.

Throughout the selection process for its launch vehicles, NASA has been thorough, transparent, subject to regular independent reviews, open to alternative ideas, and has made all of its decisions based on hard data.

Ares is a solid foundation for America’s future in space.

A Rocket's Coat of Many Colors

Why are the Ares rockets different colors on the top and bottom? Why do some rockets like the Saturn have black and white strips resembling a checkerboard? The answer to these questions may be as simple as determining what type of material a rocket is made of, or you might be surprised to learn that some of these markings assist in the successful launch of a vehicle. If you look back to the early prototypes of the V2 rockets designed by the German rocket scientists that were painted in the familiar black-and-white roll pattern scheme. This scheme was designed to aid in tracking the rocket after launch. The pattern made it easy to observe any variation or roll of the rocket, based on what colors were visible from a particular angle on the ground. Today’s vehicles can be accompanied by a detailed document called the External Vehicle Markings (EVM) Document. This manual contains everything you might need to know regarding location, size and colorings of various logos and markings on a vehicle. The markings on a rocket may change over its lifetime as the design matures, so these changes are documented in the EVM to ensure consistency. With each new variation in a rocket’s design, the pattern is examined and altered as warranted to meet new flight objectives. The Saturn V for example had a series of black markings on all three sections, or stages, of the rocket. During launch as each stage separated engineers were able to use the markings on the next stage to track the vehicle. The shuttle was designed to look more like a plane so there was no need for markings to determine its roll. However NASA’s first two orbiter test flights–STS-1 and STS-2–did have external tanks that were painted white to protect them from exposure to ultraviolet rays during extended periods on the launch pad. Later it was determined the paint wasn’t vital for tank protection, so painting was abandoned to free up weight – about 600 pounds – for additional payload. All external tanks arrive from the assembly facility are a light tan in color, and can eventually reach a chocolate brown depending on how long it sits on the pad in the sun. NASA’s newest rockets –the Ares launch vehicles – each have their own distinct appearance. The first test vehicle scheduled to fly later this year– the Ares I-X –will have a black “Z-Mark” that wraps around the first-stage solid rocket motor. This marking was added by designers to help engineers determine the orientation and roll of the vehicle during launch and ascent.

Additional markings could be added to the Ares vehicles as the development process continues. So the next time you see a rocket with its funny black, white or orange colorings remember there is probably more to the story than meets the eye.

Testing,Testing,A-1 to -3…

Engineers at NASA’s John C. Stennis Space Center are hard at work to prepare the facility for testing the J-2X rocket engines and rocket stages that will help carry humans back to the moon.

Steel work is progressing on the A-3 Test Stand, which will be used to perform high-altitude testing of the J-2X engine, a cornerstone of NASA’s Constellation Program to go back to the moon and beyond. By February, workers were completing the seventh of 16 stages of steel work necessary to erect the tower that is 300 feet tall.

Meanwhile, modification and maintenance work continues on the A-1 Test Stand, which also will test the J-2X engine and its components. It is the most extensive modification effort performed on the stand since the early 1970s, when it was converted for testing space shuttle main engines.

Engineers also continue major modifications on the B Complex Test Facility to prepare for testing stages of the Ares rockets to be used in the Constellation Program. Stennis is responsible for testing the upper stage of the Ares I crew launch vehicle and the first stage of the Ares V cargo launch vehicle. To that end, engineers are creating and installing new control systems and data acquisition and recording systems at the test complex. They also are upgrading fire and gas detection systems on the B Test Stand.

Finally, engineers are installing a new liquid nitrogen pump system at Stennis’ high-pressure gas facility. One of three pumps has been installed and already is matching the output of four older pumps while using less power and experiencing less mechanical strain and much less propellant loss. All three new pumps are scheduled to be in place in time to support the liquid nitrogen needs involved with J-2X and Ares stage testing.

Staging the Ares I

When NASA has built a rocket, it has historically been done in segments, or stages. For example, the Saturn V used to take astronauts to the moon during the Apollo program had three stages. The Constellation Program’s new Ares I rocket will have two stages – the first and upper stages.

Some have asked, why do you need stages? Why not build one large ship and be done with it? The reasoning for this is simple — most of the structure used in a launch vehicle houses the fuel needed to power the propulsion system. As the vehicle burns fuel, it no longer needs the full-sized structure to reach orbit; therefore, it becomes excess weight. By staging or dropping off these stages, the vehicle becomes lighter and the propulsion system has to push less weight into orbit.

While staging is a necessary part of the launch process, it does have potential risks and is given additional scrutiny because of the relative complexity. As with all launch events, staging is studied carefully by project engineers to ensure mission success. This is a normal part of the NASA development process. For Ares, NASA has evaluated the first-stage-to-upper-stage-separation event from the perspective of ensuring the ability to separate, being able to confirm separation has occurred, and having sufficient clearance to not re-contact the J-2X engine nozzle with the interstage as it is pulled away from the Ares I upper stage.

The separation of the Ares I stages is carefully timed and based upon preset acceleration levels. Separation will occur when those levels are read by on-board accelerometers, which takes place when the first stage runs out of propellant and the internal pressure reduces. A set of linear shaped charges between the upper stage and first stage will fire, separating the metal between the first stage and the interstage. At the same time, ten booster deceleration motors fire to pull the first stage directly backward, while eight ullage settling motors fire to push the upper stage forward. After the segments separate, the first stage tumble motors fire to slow the stage for its return trip to Earth and eventual recovery.

As part of this process, NASA engineers ran thousands of physics-based models (“Monte Carlo” analyses) to evaluate the first stage/upper stage separation. These models are developing and continue to improve. In addition, engineers analyzed and evaluated the system redundancies and potential for re-contact between the J-2X nozzle and the interstage. NASA’s analyses concluded that there will be a good separation, even in a worst case scenario. Because this is a critical event, NASA had the Aerospace Corporation perform an independent analysis and their conclusions supported the NASA analysis.

This along with many other developments is a key “risk” that will continue to be watched closely, and managed and mitigated using proven risk management techniques as we proceed with the final design phase of Ares I.

What Does It Mean to 'Human Rate' a Rocket?

A lot of people have asked what it means to “human rate” a rocket — to put people on top of a rocket and send them into space. How does an agency like NASA take on this challenge? And what considerations do engineers give human rating as they design Ares to deliver astronauts to the International Space Station by 2015 and for future trips to the moon and beyond?

In a nutshell, human-rating a rocket means that we take our understanding of how the rocket can fail to a higher level of fidelity (than for a non-human rated rocket), and then take steps to prevent failures or have it fail in such a way that the crew can survive the failure (e.g. crew abort).

For NASA, the Ares I rocket is being designed from the outset to fly humans as its primary role vs. modifying an existing system.

To get a little deeper into the subject, I talked with some senior NASA Marshall Space Flight Center engineers, Neil Otte and Gary Langford, who work this challenge for NASA and here’s how they explain it:

Let’s clearly define some of the primary human rated attributes and what they mean. First, human safety is the measure of risk of injury, or loss of life, to any spaceflight personnel. NASA’s policy is to protect the health and safety of humans involved in or exposed to space activities, specifically the public, crew, passengers, and ground personnel. Specifically human rating is involved with the risk to the flight crew. Risks to ground crew and the public are covered under other NASA policy directives and are inherent in all missions regardless of the presence of a flight crew.

A human-rated system accommodates human needs, effectively utilizes human capabilities, controls hazards and manages safety risks associated with human spaceflight, and provides, to the maximum extent practical, the capability to safely recover the crew from hazardous situations. This statement makes up the basic three tenets of human rating: assuring the total system can safely conduct the mission, incorporate design features that accommodate human interaction with the system, and incorporate design features and capabilities to enable safe recovery of the crew from hazardous situations.

Simply put, human rating is a thorough process that consists of many variables being taken into account to safely design, build and launch a crewed spacecraft and return that spacecraft, and its crew safely to the earth. The process begins at program inception and continues throughout the life cycle of the program and includes: design and development; test and verification; program management and control; flight readiness certification; mission operations; sustaining engineering; maintenance, upgrades, and disposal.

We can now look closer at human rating. The first tenet is to safely conduct the planned mission. To accomplish this requires a very careful design. This design is accomplished by a careful examination of the hazards and design features that prevent the hazard known as hazard controls. In the design, the first step would be to try eliminating the hazard; if that is not possible then hazard controls can be put into place to prevent the occurrence of the hazard. Hazard controls can take many forms such as failure tolerance by incorporating redundant or backup systems and components, application of system margins to assure function of the system even under the most extreme conditions, and quality assurance from early material and component selection through final assembly and checkout operations. If applied to a simple example of say a home heating system, the hazard would be that the house is too cold for the health and safety of the occupants. Moving to a warmer climate, however, could eliminate the hazard, if not possible then hazard controls are put into place. Use of redundant systems or components can be applied. For example, many heat pump systems have backup electrical or gas systems to provide heat in the event of a compressor failure or the inability of the compressor to meet the needed heat requirements. The system is carefully sized to provide adequate heat under the most extreme expected winter temperatures for the local climate, and the equipment manufacturer and the installation contractor control quality.

For the Ares I rocket the foundations of the first basic tenet in developing a human rated system have been carefully laid out. Factors such as hazard elimination and hazard controls have been carefully thought out and placed as requirements in the system design. In addition, program management and control places additional requirements on the development to assure adequate system margins, proper test and verification, and safety and mission assurance practices to further minimize the risk to the flight crew.

Even with all the care that goes into the system design and development, the system design must accommodate failure. Sometimes failure is dealt with by simple redundancy that allows mission continuation. In some cases, however, mission continuation is no longer possible and steps must be taken to safely return the crew. For the example of the house, for extreme cold and total system failure, the occupants could choose to leave, go stay with family or friends, or stay in a hotel until repairs are made. In short you remove the humans from the hazard. Ares accomplishes this by incorporation of the launch abort system (LAS). The LAS allows the spacecraft to be lifted away from a failing launch vehicle and allows for spacecraft reentry and rescue of the crew by search and rescue forces.

Launch of a crew to low earth orbit is an energetic process that inherently has significant associated risk. The process of human rating attempts to eliminate hazards, control the hazards that remain, and provide for crew survival even in the presence of failures that expose the crew to the hazards. The Ares Projects team was assigned the task of designing a launch vehicle capable of carrying the Orion crew exploration vehicle, with a crew of four to six astronauts, to the International Space Station AND later support lunar missions. NASA’s top priority is to design and build a vehicle that supports the crew with the safest design possible given real external constraints. The Ares design is a culmination of years of studying the best attributes for a human rated launch system. Every aspect of human rating has been taken into account in the Ares design, therefore the Ares I rocket will be fully human rated, something only achieved by a small fraction of launch vehicles.

The Ares I rocket is three years into its development process and has successfully passed every major design review. Ares is being designed with human rating in mind as the primary requirement vs. modifying an existing rocket. Human rating has been an integral part of the Ares I development since day one.