Analyzing the Flight of Ares I-X
NASA reports on the performance of its historic test flight rocket, including why the parachutes failed.
Brittany Sauser 12/03/2009
- 2 Comments
 Credit: NASA |
In late October NASA conducted the first test flight of its next-generation rocket, Ares. In a press conference at Johnson Space Center (JSC) in Houston this afternoon, project managers and engineers reported their preliminary findings.
The flight was successful in many ways, said Bob Ess, project manager of Ares I-X. For instance, it demonstrated the viability of the guidance, navigation and control systems. "The algorithms were perfect and performed flawlessly; a key result for validating our [predictive] models."
Marshall Smith, manager of systems engineering and integration for the rocket, added that Ares I-X, the tallest rocket ever to be flown, shows that "[NASA] can push forward with the design of Ares I."
The rocket's flight lasted--from liftoff to splash down--approximately six minutes, enough time for engineers to gather data on the performance of the rocket's avionic systems, accelerations and vibrations experienced, roll torque and thrust oscillation, as well as the separation of its stages.
One key problem during the flight was the malfunction of the parachutes designed to carry the rockets solid rocket booster back to earth. At an altitude of 45 kilometers the rocket's two stages separated. The first stage, composed of four solid rocket boosters and a dummy fifth segment, were dropped into the Atlantic Ocean via three large parachutes. (The mock second stage broke apart and was not recovered.) But the main parachute failed and a second parachute partially failed causing the booster to splash down hard into the ocean, leaving a nice dent in its side.
The
main parachute failed at inflation, said Smith. The parachutes are supposed to
open in three stages, and at each stage there is a cable that keeps the chutes
from opening too far. The engineers believe that one of the cables opened too
far putting too much force on the lines causing them to shear. The engineers are still investigating the
partial failure of the second chute. They plan to give two more Ares I-X performance reports--one in January and the other late February 2010.
The engineers now want to do additional tests flights in 2012 or 2013. "Each time we can make it more like Ares I, so the next [test rocket] will have a full five segment solid rocket booster," said Jon Cowart, deputy project manager. But any future test flights will be contingent on the Obama administration's decision on the future of human spaceflight.
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Gaetano Marano
246 Comments
>>> the Ares 1-X data CONFIRMS that a REAL Ares-1 can't fly >>>
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finally we know something real about the 1-X test
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the thrust oscillation seems better than expected that is a good news since, now, we know that an SRB can be launched alone and (probably) also with a manned vehicle atop it without damage for the astronauts health
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after all, the SRB safety and reliability was already evidenced by the 250+ successful SRB launches with the Shuttle, but, before this test, there was the doubt that it was so good since mitigated by the Shuttle stack mass and by the SSMEs throttling
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however, the bad news is that we are talking of the STANDARD SRB and NOT of the new and considerably different 5-segments version to be used in the final Ares-1
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a further bad news is that NASA has scrapped the (already too late, since previously planned for 2013, or later) Ares 1-Y so, only in 2017 (or later) when the first unmanned Ares-1 test "should" be performed, we'll know if also the new SRB version is so safe
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in short, the standard SRB can be launched alone with an cargo payload and (probably) also with a manned capsule atop it (despite, NOT so heavy like the current Orion design) but we can't be sure (until the 2017+ test) that also the SRB-5 could perform a launch with the same safe specs of a standard SRB
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the most interesting figure of the Ares 1-X 30 day report is at page 15 where is stated that the "Altitude at separation" has been "~128 kft (nominal ~ 129 kft)" that's around 39 km.
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unfortunately, the report doesn't give us the 1-X altitude at the 1st stage BURN OUT that is a very important data, since the flight profile of the 1-X is slightly different from a Shuttle launch
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in a Shuttle launch, both SRBs are jettisoned at 45 km. of altitude and they continue to fly due to their inertia, while they burn the residual propellant, so, the SRBs burn out happens some seconds later
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in the 1-X test, the separation is happened only AFTER the FULL burn out of the SRB (as shown also in the images of the launch) so, we must INCLUDE the extra-altitude reached thanks to the inertia of the SRB
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the given figure (39 km.) is surely better than the early (rumored) 35 km. (reported in a blog's post linked in my article about the Ares 1-X test) but, LESS good than expected, since, the 1st stage, hasn't not even reached the same altitude (45 km.) where, the Shuttle SRBs, are jettisoned !
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so, now I've some doubt about change the calculations in my Ares 1-X article, since it's UNCLEAR if the 39 km. data is the burn out AND the stage separation altitude OR if the 39 km. data is ONLY the stage separation altitude, while, the SRB burn out happened at 35 km. of altitude, with 4 extra-km. of INERTIA
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please note, that, we can't add the extra 4 km. of inertia in the count of the "useful altitude" because the rocket reaches 39 km. of altitude, from 35 km. of the SRB burn out, but, in the same time, its speed falls from mach 4.6 to ZERO
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then, I wait more clear data about this very important point before update the calculations published in my Ares 1-X article:
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http://www.ghostnasa.com/posts2/057afailedtest.html
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another important data (missed in this first report about the Ares 1-X test) to know if an SRB launched alone can be used for manned vehicles, is the time/thrust vs. G curve
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