New Mars

Scheduled for 2009, Ares I–X is planned to be the first test flight of the Ares I vehicle. The test flight objectives are focused on first-stage flight dynamics, controllability, and separation of the first and upper stages. The Ares I–X flight will consist of a functional booster stage and an upper stage mass simulator, which has the same mass as the actual upper stage.

Some Ares I “Myths” Debunked

• The Ares I is underpowered to lift the Orion CEV
–Today, Ares I has ~ 4,400lbm of total performance margin above the requirement for a driving lunar mission
–Constellation maintains an additional 3,000 lbm of margin over Orion!s maximum mass requirement (which also contains margin)
–That's 15% of margin coming into PDR. That's in addition to mass growth allowances on all systems

• The Ares I will violently shake apart during 1st stage fl flight
–Solid-based stages exhibit a phenomenon called thrust oscillation - on Ares I, particularly in the last ~20 sec of 1st stage fflight
–The Ares I is a relatively “quiet” motor (~0.5% variation in pressure) and analysis is ongoing to characterize this environment and effect on the launch stack
–Recent results suggest this is well within our design capabilities to mitigate, if necessary

• The Ares I is too long and thin and will not be controllable
–NASA has spent significant effort analyzing and testing in wind tunnels the fight dynamics of Ares I.
–The vehicle has control margin above the requirements using the heritage TVC and while long/thin, is well within the experience base of previous launch vehicles

• Ares I is behind schedule
–The Ares team has met all of its key milestones over the last 2.5 years (including 4 major acquisitions) and is on track to meet its PDR milestone in August, 2008

And where did the myths come from in the first place? With words. Oh, and here I thought you weren't going to use colored text anymore, gaetano. Seriously though, where did the original myths come from?

I wonder if they could use that 15% margin to do a direct lunar orbit shot.

Also, will the 2nd stage reach orbital velocities?

the "vibrations" issue is an official NASA claim, the same was the problem of flight stability (from press release) the doubt about the Ares-1 come from (good or bad) evaluations from several places, the Orion overweight was admitted (despite they say that have/will solve it)

at this point, that myths NEED a REAL flight to be debunked

And if the official NASA statement says its not true, why should we believe a rumor?

there is difference between a problem SOLVED and a problem they HOPE (or are SURE) to solve in the next months/years... just need to wait to see the Ares-1 to fly... if fly...

And why should we believe the rumor?

founded on baseless

By Rob Coppinger

Alliant Techsystem's development work on the first stage of NASA's Ares I crew launch vehicle is progressing, with segments for the ground vibration test article already fabricated.

Preparations are under way to ship hardware for the analog test flight Ares I-X to NASA's Kennedy Space Center by July.

Ares I's first stage is a five-segment solid rocket boster (SRB). For ground vibration testing, ATK is to supply two five-segment stacks: one empty of the solid fuel, the other an inert version of a fuelled stack.

These will be tested at NASA's Marshall Spaceflight Center in 2010. ATK has produced three of the inert stack's five segments, using them as manufacturing process pathfinders.

The Ares I-X test flight, which uses a four-segment SRB first stage with a dummy fifth segment, upper stage and Orion crew exploration vehicle payload, is scheduled for 15 April 2009. ATK expects the last of its hardware for that launch to be at Kennedy by October.

But almost two weeks before that analog flight will be the 2 April 2009 test-firing of the first five-segment development motor, DM-1. This will take place at the company's T-97 test stand, used for Shuttle SRB testing and to be modified for the five-segment booster's extra power.

DM-1 will be followed by three more tests, DM-2, -3 and -4, taking place in September 2009, August 2010 and February 2011, respectively. The segment casings for DM-1 have already flown "six or seven" times on Space Shuttle missions, says ATK Ares I programme manager Fred Brassfield.

A five-segment SRB has been fired previously - in 2003, under development work for the Shuttle programme, when the fleet was still expected to last until 2020. But beyond having five segments, the stack was no different to the Shuttle booster.

During Ares' first-stage development, ATK will be qualifying a number of changes, including: new insulation, work on which began under the Shuttle programme an altered solid fuel with reduced oxidiser levels placing of all the separation motors on the aft skirt, with one or two perpendicular to it, to kick the stage into a tumbling re-entry mode and larger parachutes for the faster descent speeds from its higher separation. Also, says Brassfield: "We need to build a larger bearing for gimballing the larger nozzle."

ATK space launch systems vice-president Michael Kahn says that, as the requirement for Ares I nozzle gimballing is "slightly less" than on the Shuttle, the thrust vector control (TVC) system does not have to be changed.

But a TVC system that uses helium to drive the actuator hydraulics, instead of hydrazine, is being examined as a potential life-cycle cost-reduction effort because it removes the expensive controls and precautions required when dealing with a hazardous chemical such as hydrazine.

One element of the first-stage design that will not change is the segment's metal casings, says Kahn. The loading on them from the combined mass of the upper stage and CEV will be no higher than that experienced during Shuttle launches, he adds.