posted 08-10-2007 04:31 PM               

NASA Awards First Stage Contract for Ares Rockets

NASA has signed a $1.8 billion contract with Alliant Techsystems, known as ATK, located near Brigham City, Utah, for the design, development, testing, and evaluation of the first stage of the Ares I and Ares V launch vehicles.

This contract continues work that began on April 17, 2006, and includes delivery of five ground static test motors, two ground vibration test articles and four flight test stages, including one for the Ares I-X test flight.

NASA awarded the cost-plus-award-fee contract to ATK on a sole-source basis. The contract performance period extends through Dec. 31, 2014. First stage boosters for operational missions will be purchased through a separate contract.

ATK and its subcontractors possess the unique engineering capabilities for successful design and development of the first stage of the Ares I crew launch vehicle. The current space shuttle solid rocket booster is the only solid rocket booster manufactured in the United States that possesses both the required capabilities and safety margins necessary for the launch of a human-rated exploration space vehicle. These solid rocket boosters consistently have proven their capabilities and demonstrated reliability needed for the human exploration missions.

The Ares I first stage will be a five-segment solid rocket booster based on the four-segment design used for the shuttle. The basic design will draw on current hardware, facilities and manufacturing equipment qualified for human-rated solid rocket boosters.

The first stage will incorporate modifications to the current booster that are unique to the Ares I architecture to meet higher performance and reliability requirements for the Ares vehicles. Modifications include the additional segment and new solid rocket booster components.

Ares I is an in-line, two-stage rocket that will transport the Orion crew exploration vehicle to low Earth orbit. Orion will accommodate as many as six astronauts. The first stage will consist of the five-segment solid rocket booster. The second, or upper, stage will consist of a J-2X liquid-oxygen, liquid-hydrogen engine, a new upper stage fuel tank and associated avionics.

Ares V will enable NASA to launch a variety of science and exploration payloads, as well as key components, needed to travel to the moon and later to Mars. Ares V, a heavy-lift launch vehicle, is currently projected to use five RS-68 liquid-oxygen, liquid-hydrogen engines mounted below a larger version of the shuttle's external tank and two five-segment, solid-propellant rocket boosters for the first stage. The upper stage will use the same J-2X engine as the Ares I.

The first stage is managed by NASA's Marshall Space Flight Center in Huntsville, Ala., for NASA's Constellation Program.

posted 08-13-2007 04:38 PM               

Ares I will stand approximately 330 feet tall and Ares V will top off at about 360 feet. In that regard, both will be closer in stature to the Saturn V's 363 feet of booster.

Ares I will use a five-segment solid rocket booster as its first stage, providing a 10 percent increase in thrust over the four segment version used currently to launch the space shuttle. In October 2003, ATK performed a test fire of a five-segment SRB:

Ares V's first stage will employ two five-segment SRBs with a cluster of five RS-68 liquid-fueled engines. The RS-68 is the largest existing liquid hydrogen / liquid oxygen engine. As a comparison, the Delta IV Heavy uses three RS-68s:

posted 08-13-2007 05:01 PM               

quote:

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Originally posted by fabfivefreddy:
Will this give us a fireworks display as big as the Saturn V?

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posted 08-23-2007 08:44 AM               

quote:

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Originally posted by Ben:
In terms of thrust, the Ares I is about half of the shuttle and Saturn V, while Ares V is much much more than the Saturn V. Ares V should be the most powerful rocket in history in terms of thrust.

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posted 08-30-2007 07:52 AM            

Whoever thought of making them segmented needs their heads seeing to and whoever agreed to them actually being used is even worse.

posted 08-31-2007 06:26 AM               

Ares 1 will have the LAS, so if a solid does cook off, the crew has a way out. It won't matter with Ares V, since that will be an unmanned HLLV anyway. But even then, failure of the SRB aft field joint on STS-51L not withstanding, the Shuttle SRBs have had a great performance and safety record. Granted there have been some issues, but the solids are a pretty well understood piece of engineering.

posted 08-31-2007 09:23 AM               

quote:

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Originally posted by Jay Chladek:
Segmented SRBs are by no means unique to the shuttle program, or Ares.

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posted 09-01-2007 11:49 PM               

As for single point failure, yes there is that with the first stage of Ares, but that is splitting a hair. The reason I say that is although Shuttle doesn't use the SRBs exclusively, they are by and large the biggest producers of thrust. If anything, shuttle has a worse stage one profile then Orion. If the SSMEs shut down at launch and by some fluke the SRBs fire, then that stack isn't going very far is it will likely lean into the shuttle from the side loads and crash downrange (assuming the RSO doesn't destruct the vehicle at that point). With an SRB not firing, it is a worse situation. Wouldn't the failure of an SRB on shuttle be classified as a "single point" failure? There is certainly no backup for them.

Plus shuttle does not have a bailout option during first stage firing. The shuttle can't come off the tank fast enough if something happens, and it has been suggested in sim studies that if the crew tried to do a fast jettison, the orbiter would hang on the aft struts, pitch up nose first on the aft struts and then get ripped apart by the supersonic slipstream ala Challenger (assuming catastrophe from a solid that caused the abort didn't occur already). The difference here though is that the crew on Orion can abort safely.

posted 09-10-2007 12:21 AM               

Without going into too much detail (because I don't remember all of it and I don't have the article I read about it), the first Ariane V was lost due to the INS system failing when the stack got this huge side gust of upper level winds. The secondary mode of the INS, which measures in small units as it takes readings of the final positioning of the booster on the pad prior to launch, was left on since that procedure didn't cause problems on Ariane IV. But this time the side gust put such a big deviation number in the system that it couldn't calculate it. It was like a calculator coming up "E" on the screen. So the system shut down and so did the backup, resulting in the flight going out of control and having to be terminated. The worst bit is when EADS (the contractor) ran the numbers in simulators after the fact, they found out the failure was inevitable.

posted 11-07-2007 09:10 AM               

The Ares I programme has been dogged by rumours of inadequate performance and blamed for repeated redesigns of the Orion's crew and service modules driven by the need to reduce mass. NASA has refuted the rumours and maintained that the Ares I CLV is capable of meeting requirements.

But now the agency's November internal circular says: "There are significant threats to the performance to be worked as the project works towards [PDR]."

posted 11-20-2007 12:27 AM               

quote:

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Originally posted by Jay Chladek:
I've thought about the solids, and I don't have a real problem with it.

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posted 01-22-2008 04:07 PM               

Engineers are concerned that a new rocket, the Ares I, which will replace the space shuttle and send astronauts on their way to the moon, could shake violently during the first minutes of flight.

The problem is common to solid rocket boosters.

If not corrected, the shaking, which arises from the powerful first stage of the rocket, could "shake apart the whole structure," said Paul Fischbeck, an engineering professor at Carnegie Mellon University.

posted 01-23-2008 12:04 PM               

quote:

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Originally posted by KSCartist:
In fact one of them said that the Atlas V is under consideration to boost the Orion CSM into orbit.

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posted 01-24-2008 03:09 PM               

A transcript of his remarks (PDF) is available.

During a Q&A session that followed, Griffin said of the oscillation problems raised earlier in this thread, "I think I have rarely seen more of a mountain made out of less of a molehill than this particular technical issue."

posted 02-07-2008 01:02 PM               

quote:

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Originally posted by KSCartist:
In fact one of them said that the Atlas V is under consideration to boost the Orion CSM into orbit.

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Let me get down to the bottom of it. There were winners and losers in the contractor community as to who was going to get to do what on the next system post shuttle. And we didn't pick (Lockheed Martin's) Atlas 5, in consultation with the Air Force for that matter, because it wasn't the right vehicle for the lunar job. Obviously, we did pick others. So people who didn't get picked see an opportunity to throw the issue into controversy and maybe have it come out their way.

In point of fact, the thrust oscillation, as it's called, on Ares 1 is not a significant problem and to the extent that it needs solutions, we've got three or four ways to go after it. We can put damping mechanisms between the first and second stage, beteween the second stage and Orion or within Orion itself to locally isolate things. This is something that's done on almost all of our unmanned vehicles, they have solid strap-ons and this thrust oscillation issue is one of the vibration drivers on most satellite vehicles and the satellites designed to fly on them have damping and isolation devices at the frequencies of interest, and that's what we'll do here.

I think you have been around long enough to know technically this is just not a big deal. It's about winners and losers. In the larger context, it's about winners and losers and people seeing an opportunity to reclaim a share of the pie that was lost. And I hate it when it comes to that. But that's it. The fact of the matter is, Ares, the rocket, and Constellation, the program, are designed to go to the moon and to provide a capability, if necessary, to service the space station in Earth orbit.

The Atlas 5 needs substantial upgrades in order to be a useful part of the lunar architecture and those upgrades, when we added them all up, cost more than the Ares 1. It's that simple. Now if you just want to go to low-Earth orbit and nowhere else, then the Atlas 5 will do just fine. And I encourage its use for that. What I don't encourage is for people to say that going to low-Earth orbit and stopping there again is a good goal. That's not what we're trying to do. We're trying to get back to the moon and we want to go on to Mars. And that needs something bigger.

posted 02-19-2008 04:42 AM               

With a solid fuel rocket, the fuel starts burning at the bottom and combusts toward the top.