The Ares-1 can't fly
November 4, 2007

Now that NASA has assigned ALL the Ares-1 contracts (to Pratt & Whitney Rocketdyne, ATK and Boeing) this rocket has no alternative (as clearly explained two months ago in my ghostNASA article) but, unfortunately, the latest Ares-1 specs (in this page) shows that the Ares-1 can't fly (as predicted 15 months ago in my 5-segments SRB article).

Of course, the NASA engineers will take all efforts to avoid the Ares-I to fail, but so far this rocket seems unable to perform a lift-off...

I've evaluated that a single (3.3 Mlbs. peak thrust) standard 4-segments SRB can lift a 240 mT upperstages' mass to 45 km. of altitude at 3G or 190 mT to 60 km. of altitude.

My evaluation matches the early (standard SRB + SSME) CLV specs (left) released by NASA in 2005 where a 586 mT standard SRB (without its Nose Cap) lifts 182 mT of upperstages' mass (2nd stage, interstages, Orion, SM and LAS) to the 55 km. 1st stage SRB separation altitude.

The Ares-1 data shows that the new 1st stage 5-segments SRB has the same Isp of the "old" 4-segments SRB and adds a +7% to the SRB's peak thrust (now is 3,510,791 lbf.) to lift the heavier (182 mT +7%) 192 mT upperstages' mass (2nd stage, Orion, SM, interstages and LAS) of the new Ares-I, but (also) ADDS the 145.5 mT "extra-mass" of the new SRB's 5th segment (626.4 mT SRB propellent + 105.1 mT dry mass = 731.5 mT new SRB mass - 586 mT standard SRB mass = 145.5 mT 5th segment's "extra-mass") to the total mass it must lift.

Then, we MUST subtract the SRB 5th segment 145.5 mT "extra mass" from the 192 mT MAX upperstages' mass (the new SRB can lift) and the result is that the new Ares-1 will be able to lift ONLY a (very modest!) 46.5 mT upperstages' mass!!!

In other words, if NASA (really) puts 192 mT of mass (2nd stage, Orion, etc.) atop the new 5-segments SRB 1st stage, the latest Ares-1 can't leave the launch pad!!!

Please note, that, these calculations can be confuted ONLY if the Ares-1 basic data will be VERY MUCH DIFFERENT than now.

From this point of view the Ares 1-X test (a 4-segments SRB launched with a dummy upperstage) scheduled for april 2009 clearly is a TOTAL NONSENSE since it WILL leave the launch pad but ONLY because it will have NOT the 5th segment's "extra mass" and has a lighter dummy upperstage, so, it's an absolutely USELESS test!

However, the solution to this problem is very simple: restore the standard 4-segments SRB as 1st stage and resize the Orion to have a ligher upperstages' mass of about 190 mT total with a reusable SRB or over 200 mT if an expendable SRB is used WITHOUT NEED to develop a new rocket like my FAST-SLV or other similar (but LATER) concepts.

The Orion's mass can be reduced very much as expained in my articles about an EggCEV, the BigelowOrion, a lighter Orion, the underside LAS and some EASY ways to CUT weight, also, the Ares-1 could be redesigned as suggested in my new Ares and Ares-F articles.

Another BIG advantage of the "4-segments SRB solution" is a GIANT saving of money, since, the $3 billion planned to develop the 5-segments SRB, could be now used to BUY up to 75 reusable 4-segments SRB or 68 expendable 4-segments SRB (to lift more payload mass) enough for 3 test launches, 12 orbital flights and up to 15 moon missions!

Note: months ago, NASA has claimed they want to adopt ONLY the METRIC system, so, why do we STILL see "lbs", "ft", "nmi", etc. in ALL official NASA documents?


[update] There is another problem I've remarked over one year ago on a Space forum... the SRBs are NOT born to have any "upperstages' mass" since they fly side-mounted on the Shuttle... then, my question was and still is: CAN the SRB structure (especially the RINGS junctions) support up to 200 mT of upperstages' mass without any risks to crack due to the strong flight's stress?

If real tests (like the Ares 1-X launch in 2009) will show that a standard structure can't support so much upperstages' mass, the new SRB must be reinforced adding much more weight to the (already too heavy) 1st stage of the Ares-1.


[update] The 5-segments SRB's 3.5 Mlbs. is the PEAK thrust available a few seconds after lift-off and for about 15 seconds, then, the SRB thrust falls, falls, falls, falls to half and less within the 123 seconds of the SRB burning (see the graph below about the SRB thrust curve) then, the SRB "peak" thrust is a good figure to do a comparison, but NOT to know how much tons the new SRB can lift to 55+ km. of altitude.

That's why the early CLV upperstages' mass (calculated by NASA engineers!) was ONLY 182 mT MAX and NOT "250 mT", "300 mT" or more (as the 3.3 Mlbs. peak thrust of the standard SRB could suggest...).

A solid propellent motor can't give a constant thrust (to lift more upperstages' mass) because it's thrust figure/curve depends ONLY from the propellent's internal shape (that in a shuttle-SRB is an 11-points star) infact, each shuttle-SRB can lift itself and ONLY 240 mT of (shuttle, ET, payload) mass to 45 km. of altitude.

Do you know why the Shuttle flys?

It flys thanks to its three SSME that can "throttle" between 67% and "109%" ...all these engines starts with 104% the power at lift-off then "throttle down" in the first seconds after lift-off to compensate the high SRB thrust and to keep the acceleration to 3G max, then, when the SRB thrust falls, they "throttle up" again to lift the Shuttle to LEO, that, also, thanks to the SSME vacuum thrust that reaches over 512 klb. (while the sea level thrust of the SSME is only 408 klb.).

If you start from the REAL figures of the max upperstages' mass of both 4-segments and 5-segments motors (that NASA give in its OFFICIAL documents) you will discover that a 5-segments SRB can't lift (both) 192 mT of upperstages' mass AND the 5th segment's "extra-mass" to 55+ km. of altitude.

That since the Ares-1 has no "throttleable" SSMEs in the 1st stage... about this point, I doubt the astronauts can survive the lift-off since, the uncontrollable SRB thrust in the 10-15 seconds after lift-off, could give a LAS-like high-G acceleration.


[update] Since you could still have some (or many) doubts that a problem exists, here I show you a further calculation not starting from the 5-segments Ares-1 but in an inverse way, from the early CLV specs (see the first image in this page) up to the 5th segment upgrade of the latest Ares-1 design (BOTH rockets from original NASA documents).

The early CLV design was made around a standard (shuttle-derived) 4-segments SRB (as 1st stage) and an air-started SSME (as 2nd stage) with these main specs:

Global Lift Off Weight (GLOW) = 768 mT
1st stage 4-segments SRB mass = 586 mT
Global upperstages' mass = 182 mT

Then, each 146.5 mT segment of the 1st stage can lift itself AND an upperstages' mass of 45.5 mT.

Well, if we upgrade the CLV with a "pure" (or "theoric") 5th segment (that adds +25% of weight, but, also, a +25% of thrust) the 1st stage mass reaches 732.5 mT (like the new 5-segments Ares-1) and the upperstages' mass "should" reach (but can't reach in the REAL Ares-1) 227.5 mT.

From these basic specs, we can calculate the MINIMUM INCREASE OF THRUST the 5th segment MUST add to the new (upgraded) rocket to lift ITS OWN ADDITIONAL WEIGHT (+146.5 mT) then, WITHOUT any additional (+45.5 mT) upperstages' mass.

This is the equation applied to know the % of increase of thrust to lift the 5th segment:

(5th segment mass + additional upperstages' mass) : 25% = 5th segment mass : X%

Then, we can calculate the % of increase of thrust with the real data from CLV specs:

(25% x 146.5 mT) / (146.5 mT + 45.5 mT) = 19% (rounded)

In other words, the additional 5th segment of the new 1st stage MUST add (AT LEAST) +19% of thrust (to the basic 4-segments 1st stage) ONLY TO LIFT ITS OWN WEIGHT, without any additional upperstages' mass!

If we add 10 mT of upperstages' mass (like is in the latest Ares-1 specs) the MINIMUM % of increase of thrust MUST BE:

(25% x (146.5 mT + 10 mT)) / (146.5 mT + 45.5 mT) = 20.4% (rounded)

Unfortunately, the increase of PEAK thrust of the 5-segments SRB is a mere +4.1% (as shown in the comparison table below) while the increase of AVERAGE thrust is less than 14.6% (mainly in the MIDDLE of the 1st stage thrust-curve, when the Ares-1 already MUST be in flight!) then, BOTH "peak" and "average" thrust of the new 5-segments SRB are WELL UNDER the MINIMUM thrust it NEEDS to lift ITS OWN additional weight!!!

But the problems of the latest Ares-1 design are WORSE than this since this new rocket has (also) a LESS POWERFUL 2nd stage engine!

Both (CLV and Ares-1) rockets reach a similar SRB separation altitude (around 55 km.) have a similar upperstages' weight (182 mT vs. 192 mT) and burn a similar amount of 2nd stage propellents (130 mT vs. 137 mT) but, while the old CLV design use a powerful air-started SSME, the new Ares-1 design adopts a (now unavailable) J-2X engine that has 43% LESS vacuum thrust (294 Klbs for the J-2X vs. over 512 klbs for the SSME) also, the J-2X vacuum Isp (448 sec.) is lower than the SSME vacuum Isp (453 sec.).

Then, if physics and rocket science (like mathematics) are not an opinion, the new, but 43% LESS powerful, J-2X engine should NOT be able to lift the 192 mT of upperstages' mass of the new Ares-1 but (only) LESS than 104 mT.

Just add that, the current design's Orion is (at least) 1.5 mT "overweighted" and that also the (latest designed) Orion's 6.35 mT tower-LAS is 2.3 mT heavier than the 4 mT tower-LAS of the early CLV designs, then, the Ares-1 2nd stage engine should be (at least) 15% MORE powerful than an SSME rather than 43% LESS powerful.

However, the problem of the "underpowered" 2nd stage engine, could be easy to solve using TWO J-2X or (best) resizing the J-2X to an SSME-class "superengine" that I've proposed FIRST (again) in my September 6, 2007 article and that I've called "J-2Y".

Two J-2X or one J-2Y could give enough thrust to (both) the Ares-1 and Ares-5 2nd stages to lift their payloads (now the Ares-5 can lift 13 mT LESS payload than planned) but add further weight and can't solve the "more extra-weight than extra-thrust" issue of the 5-segments SRBs on both rockets.


[update] As suggested 14 MONTHS AGO in this article of my OLD ghostNASA blog, now seems that NASA could use ONLY the "expendable SRBs" for (both) Ares-1 and Ares-5 to save (about) 10 mT of 1st stage mass (maybe, to add it to the upperstages' mass).

Unfortunately, this small cut of the 1st stage mass can't solve the Ares-1 problems, not even if that (saved) mass will be used to increase the 2nd stage propellents' mass!


[update] From a Nov. 16, 2007 SpaceRef article seems that "according to NASA sources, the Ares 1 first stage, as currently designed, would produce a frequency of 25 Hz at liftoff. The concern is that this oscillation could shake the Ares 1 upper stage and Orion capsule designed to carry human passengers, causing considerable damage and that it could also adversely affect the Guidance, Navigation, and Control avionics in the rocket's Instrumentation Unit" and that "NASA sources also report that the 6 month slip in the Ares 1 PDR (Preliminary Design Review) recently announced could impact the first launch of humans aboard an Ares 1 by as much as 14-16 months beyond the announced first flight date of March 2015", then, the Orion (ready in 2012) will not fly soon and will be "freezed" four+ years, until the Ares-1 will be (IF will be) ready for manned launches, the first manned Orion launch slips to June 2016, the "american manned-flights' GAP" will be (now) at least of SIX years + further delays and the first moon landing mission could slip to 2022+ rather than "2012" for the first Orion orbital/ISS mission and "2018" for the first lunar mission (as scheduled in the early ESAS plan) ...and all that (including the 4+ years delay) in the first two years (late 2005 / late 2007) of the ESAS plan.


[update] There is a largely unknown Aug. 3, 2006 press release where NASA admits that "The "biggest unknown" for engineers, remains how to control the Ares 1’s steering and roll during flight. Engineers are using computer models and other analyses to solve the problem." (that could be a serious in-flight stability risk).


[update] A further (safety) problem of (both) 4 and 5 segments SRBs, if used to launch a manned vehicle, is that, once started, it can't stop until its solid propellent ends, then, no safe lift-off abort mode is possible with a solid booster (as I've remarked two years ago on a Space forum) while (e.g.) the Shuttle's SSMEs can be shut off in the early 6.6 seconds (between T-6.6 and T-0) before the launch when the two SRBs start (as really happened six times in the Shuttle's story saving the astronauts' lives).

The Orion will have an "old style" tower-LAS that should be able to lift the capsule from launch pad to about 4,000 ft. in a few seconds at 15G peak acceleration, that's (itself) an harrowing and dangerous force for the astronauts.

Two years ago, when I've FIRST remarked on a Space forum the problem of the lack of a "safe lift-off abort mode" in the upcoming Ares-1, I was (literally) submerged by lots of critics and insults, but, now, surfing the web, I've found and SAVED (a "disliked" web page can disappear overnight...) a very interesting June 12, 1997 Boeing's News Release titled "Boeing To Study Liquid Fly Back Shuttle Boosters For NASA" where the Boeing LFBB Program Director Ira Victer said that... "LFBB will use liquid propellants and will be fully throttleable and capable of safe shutdown. SRBs, which use a solid propellant, cannot be turned off once ignited... "The result is a booster system [the LFBB] more tolerant of engine failure and less likely to require mission aborts," Victer said. "In addition, hazardous booster operations in NASA Kennedy Space Center (KSC) Vehicle Assembly Building are eliminated, since LFBB fueling operations would occur on the launch pad, much the way the Shuttle's external tank is loaded today".

Then, in this ten-years-old document, BOEING (clearly) seems agree with me... :)

However, I'm not against the SRBs used as 1st stage of a rocket for manned launches... my only concern is that, this solution, needs many safety, structure and acceleration tests made NOW (not in 2009+) then, BEFORE any "final decision" about the Ares-1.


[update] Apart of the rumors, that, in its latest design cycle, it seems able to lift 13 mT LESS payload than planned, also the Ares-5 can't fly since it has TWICE the problem of the Ares-1 (having TWO 5-segments SRBs) as (again) predicted over 15 months ago in my 5-segments SRB article.

It's not easy to evaluate the Ares-5 performances without the NASA full/real data and a simulation software, since this new rocket is largely different from SaturnV, CLV, Ares-1, Space Shuttle and other common rockets like Atlas and Delta, however, my evaluation of an Ares-5 with two standard 4-segments SRBs say that, starting from the global sea level SRBs and RS-68s lift-off thrust (of about 9.64 Mlbf.) this rocket should be able to lift about 2900 mT.

If we exclude from the 2900 mT GLOW the 137 mT Core Stage Dry Mass, the 1396 mT Core Stage Propellant Mass and the 590+590 mT (standard) 4-segments 2xSRB Mass, the MAX Upperstages' Mass this version of Ares-5 may lift is about (2900 mT -137 mT -1396 mT -590 mT -590 mT) = 187 mT that is NOT "only" 13 mT less but 98 mT LESS than the (planned) global (minimum) upperstages' mass of 285.4 mT (40.4 mT the LSAM + 223.5 mT of propellent + 21.5 mT the 2nd stage/EDS dry mass).

In other words, the Ares-5 with two standard 4-segments SRBs seems able to lift the 2nd stage/EDS (and part of the propellent) but NOT the LSAM payload and great part of the propellent for the TLI burn.

Changing the standard 4-segments SRBs with two 5-segments SRBs (and assuming an increase of peak/lift-off thrust around +7% for each 5-segments SRB) the max lift-off thrust of the Ares-5 could reach 10.44 Mlbf. and its max GLOW goes up to 3130 mT, but the two 5-segments SRB add 290+ mT of extra-mass, then, the max upperstages' mass (2nd stage/EDS + propellent + payload) of the Ares-5 could fall to (3130 mT -137 mT -1396 mT -590 mT -590 mT -290 mT) = 127 mT, then, also the Ares-5 can't fly, with or without its 130 mT payload!!!

 

[ click to enlarge ]


[update] For those who are still skeptic about what I've said here, in this latest update I explain, step by step, that concepts from a different (historical/technical/evolutionary) point of view.

The 4-segments SRB was developed over 30 years ago and never changed in its specs and performances, but used 240 times in over 26 years for 120 Shuttle flights, with just ONE failure in the Challenger accident.

Since the standard-SRB specs are well known and never changed in 26+ years, it's very easy to evaluate (thanks to so many REAL flights) the EXACT performance of the SRB boosters and how much mass a single standard-SRB can lift to 45 km. of altitude (where both SRBs are jettisoned).

We know, from the Space Shuttle specs, that its system-stack GLOW is ~2040 mT and the lift-off thrust is ~6.8 Mlbf (~2.8 Mlbf each SRB and ~400 klbf each SSME) with a small increase (a few seconds after lift-off and for ~10 seconds) when the SRBs reach their peak thrust.

Starting from these data, it's easy to calculate the lifted mass per Mlbf of thrust (that is 2040 mT / 6.8 Mlbf = 300 mT) the max lifted mass of a standard-SRB including its own mass (that is 300 mT x 2.8 Mlbf = 840 mT) and the max lifted mass a (standard) Shuttle's SRB "should" lift EXCLUDING its own (590 mT) mass to 45 km. altitude at 3G max (that is 840 mT - 590 mT = 250 mT).

250 mT of lifted mass (over its own weight) sounds an excellent figure for a standard SRB, but, unfortunately, this evaluation is too optimistic since:

1. at lift-off, each SSME has a sea level Isp of 363 sec. while each SRB has a sea level Isp of only 237 sec.

2. the SSME thrust quickly RISES to over 512 klbs at 453 sec. of Isp in the vacuum,

3. while, the SRB thrust quickly FALLS after a few seconds of peak power (see the SRB thrust curve published here).

So, the SSME's "slice" of lifted Space Shuttle's GLOW is HIGHER while the SRB's "slice" of lifted mass is LOWER (probably under 220 mT per SRB excluding the SRB own mass).

Then, also my early evaluation of 240 mT lifted mass (to 45 km. of altitude at 3G) was too optimistic and that is confirmed by (both) CLV and Ares-1 max upperstages' mass.

Also (both) optimistic figures can be applied in a Shuttle flight, while, in a CLV or Ares-1 flight (where the 1st stage must reach 55-60 km. of altitude and the acceleration goes up to 4G) the SRB's max lifted/upperstages' mass should be in the range of 180 mT with a reusable booster and 10-12 mT more (the weight of the SRB's retrieval system) with an expendable SRB.

Someone could say that a standard SRB can lift MORE upperstages' mass since it should have a (so far not used) "reserve of power", but this is ABSOLUTELY IMPOSSIBLE for several good (or very good) reasons:

1. only the liquid propellents' engines (and a, recently developed, but experimental, small solid engine) can "throttle down" to 40-60% their max power (or less, like the 10% of the lunar landers' engines in the last meters before the landers' touch down) then, could have a "reserve of power" (if not used before, of course) while, the SRBs (like all other solid boosters) once ignited, ALWAYS release their FULL POWER and can't be throttled, so, the "power" that a Shuttle's (standard) SRBs give, actually IS, also, the MAX power it can give, and the ~220 mT "slice" of Space Shuttle mass (excluding the SRB weight) lifted by each standard SRB, actually IS, also, the MAX shared mass each SRB can lift,

2. since the solid propellents' standard-SRB release its FULL POWER, a "lighter" Space Shuttle (with a "reserve of usable mass", then, an SRB's "reserve of usable power") MUST fly at higher speed and with an higher acceleration but, in all flights, the Shuttle speed was/is/will be the SAME and its acceleration remains within 3G (that's the Shuttle main difference vs. the past NASA vehicles like Gemini, when the astronauts experienced up to 7G at launch) then, the Shuttle doesn't have any (further) "reserve of mass" and the SRB doesn't have any "reserve of power" to be used in the Ares-1,

3. according to NASA, the max Shuttle's payload to 100 nmi orbit was 28 mT but this figure was reduced for safety reasons to 24 mT max (according to Astronautix) after the Challenger accident (but Wikipedia give a 22.7 mT figure) while the max payload to the ISS orbit at 220 nmi is around 20 mT, then, the max Shuttle "reserve of mass" is in the range of a few mT and the Space Shuttle has always flown, fly and will fly pretty close to its GLOW, payload and motors/engines' LIMITS,

4. the price to launch each kg to LEO, still very high to-day, was very much higher in the past 26 years, then, should be absurd and not credible (then, NOT TRUE) that ALL Shuttle missions was/are launched with 50, 100 or more tons UNDER its REAL capacity and that NASA has NEVER used that Shuttle's "reserve of usable mass" and the SRB's "reserve of usable power",

5. but the "mother of all evidences" that a Shuttle (and its standard SRBs) hasn't any further "reserve of power", are the '90s' NASA studies to upgrade the Space Shuttle, replacing the 4-segments SRBs with two 5-segments SRBs or two liquid Fly-Back booster (see also this Boeing's News Release) and/or a super lightweight External Tank, to save a few tons and to increase the payload by just 3.5 mT more (with the lightweight ET) that clearly means that (both) Space Shuttle and SRBs have flown (and still fly) pretty close to their GLOW, payload and motors/engines' LIMITS.

I don't know why the Space Shuttle, despite its two powerful boosters, can't lift dozens or hundreds more tons of vehicle/propellents/payload mass, but I know (like everybody know) that these are the REAL figures from 26+ years of REAL Shuttle/SRB flights!!!

Going one step ahead in this analysis we must look at the early CLV specs (first image in this page) based on the standard 4-segments SRB as 1st stage and an air-started SSME as 2nd stage engine.

The idea of the CLV aka "Stick" (that a german Space forum's user calls "asparagus") is not new since (according to this Space Launch Report article) the early concepts' study of this kind of rocket begin at NASA in 1993 with the ATSS Solid Booster In-Line Rocket.

The CLV and Ares-1 to launch the manned Orion (as we know it now) was an invention made by the former Chief of the NASA Exploration Systems Mission Directorate (and head of the Constellation Program) Scott "Doc" Horowitz (when it was at ATK) and the NASA Administrator already talks of it in this July 2004 Planetary Society's Griffin-Garriot study.

So, the CLV research at NASA is (at least) ten years old and several different versions and configurations was studied to end with the "final" ESAS plan's choice of the standard SRB + SSME version (then, changed, just a few months after the ESAS publication, with the current 5-segments SRB + J-2X version).

The CLV specs are not "random numbers" or an "engineers' guess" but the result of ten+ years of study and research, then, from the CLV specs, published here, we know that a standard 4-segments SRB launched alone, is able to lift 182 mT of upperstages' mass, to about 55 km. of altitude (the Ares-1 first stage separation altitude) at 2.93G max.

Maybe, the real launch-test performances of this rocket, could be slightly different than planned, but just a few tons more or less, NOT several tons higher, since the CLV specs comes from years of studies and (most important) perfectly matches the REAL Space Shuttle's standard-SRB specs experienced in 26 years of REAL Shuttle flights, with 120 REAL launches and 240 boosters burned.

The last step of my analysis is the current 5-segments SRB Ares-1 that, according to its latest specs (released one month ago and published here) and despite its additional 5th segment, should be able to lift just 10 mT more upperstages' mass (only 192 mT vs. 182 mT) than the (4-segments SRB + SSME) early CLV design.

Please note that this +10 mT extra-mass is NOT an "extra-payload" but includes ALL the (2nd stage, propellents, interstages, Orion, SM and LAS) upperstages' mass, so, the REAL "advantage" of the 5-segments SRB vs. the 4-segments SRB (used as 1st stage of the Ares-1) is MINIMAL since, if we consider the Ares-1 upperstages' mass vs. payload mass ratio (192 mT vs. 25.5 mT max) the increased payload mass is just 1.3 mT.

In other words (and assuming that Ares-1 will really fly...) NASA will lose THREE YEARS of time and THREE BILLION$$$ (to develop the 5-segments SRB) to ONLY add a mere 1.3 mT of extra-payload to an (already too big and heavy) six-seats Orion.

It clearly is an ABSURD CHOICE and a ABSOLUTE NONSENSE since, adopting a slightly resized (4.5/4.8 m. 4/5 seats) Orion and a 4-segments SRB 1st stage, they could SAVE (both) TIME and MONEY and launch the first manned Orion SOONER than planned.


[update] From this NSF article: "Each new reusable 5.5 segment SRB, will contain over 1.5 million pounds of propellant which will produce a peak of 3,774,000 million lbs of thrust and will have a vacuum Isp of 275.5 seconds. The 38 percent larger SRB's will burn for...

116 seconds

...a full 8 seconds shorter burn time than Space Shuttle - before being jettisoned."

From my (Mar 01, 2008) NewMars' post: "that means its propellent will burn 9.1% faster, so, the burn time should fall from 128 seconds to...

116.3 seconds

...the thrust may be increased in a similar value, that means the (known) past SRB-5 had a lack of thrust, like the 4+1 SRB test has shown in 2003 and like I've said in my SRB-5 and Ares-1 articles (so, I was right, again... :) )"

Then, 2.5 months ago I was RIGHT also on the most minute details of the new SRB5!!!

An explanation for those who don't read the NewMars thread: the new 5 or 5.5 segments SRBs should have an internal "12 points star" solid propellent's shape, while the standard 4-segments Shuttle's SRBs have an "11 points star" shape, so, the internal propellent's shape surface of the new SRB5, will be about 9.1% larger and the solid propellents will burn (about) 9.1% faster than a standard SRB, then, the burning time of a 5 (or 5.5) segments SRB (with its "12 points star shape") should burn (about) 116 seconds, rather than 124 seconds, like a Shuttle's SRB, or 128 seconds, like a 5/5.5 segments SRB made with the old "11 points star" propellent's shape; that means (also) the Ares-1 first stage should NOT be able to fly to and be jettisoned at 55-57 km. of altitude (vs. the 45 km. altitude, where the Shuttle's SRBs are jettisoned) but at a much lower altitude (around 50 km.) since the Ares-1 will (or should...) fly at 3.5/3.8G (vs. the Shuttle's 3G max) so (as said/explained several times in my articles) a single J-2X can't have enough power to lift the Ares-1's upperstages mass, then, TWO J-2X (or a much powerful "J-2Y") will be absolutely necessary!


[update] Latest news (at Jun 27, 2008) say that (after several delays) the first manned Orion flight is planned for March 2016 assuming no other, possible, launch delays occur, that means the first (new) manned lunar landing should happen in 2022 or LATER... :(


[update] 14 months after this article was published online and six months after its latest update, I've (finally!) found the time to update it again, with several very interesting info and news happened in past months.

The most important news last year was the Ares-1 thrust oscillation issue as revealed by NASA (one year ago) after some Ares-1 computer simulations they've accomplished, but, new data gathered by sensors put on the standard SRBs of the STS-126 Shuttle mission last november and further computer simulations said them that (probably) the "vibrations issue" concern was overstated, so, a the Ares-1 "active damping" should be unneeded.

Last August, the first failed test launch of the ALV X-1 (destroyed shortly after launch due to a bad trajectory) from Wallops Island CLEARLY demonstrated HOW DANGEROUS a solid motor rocket could be if launched ALONE (without the Space Shuttle's stack) if something goes wrong, then (again) I was right in my concerns about the use of a solid motor (that can't be shutted off once burned) as 1st stage of the Ares-1 as explained in my January 24, 2008 article.

Then, last October a further Ares-1 problem has been leaked (and, later, confirmed) from NASA about a possibly dangerous "liftoff drift" issue (under fast winds conditions) that could damage the launch pad and the Ares-1 putting the Orion's crew at serious risk, however, it doesn't look like a big problem to solve since there are several ways to fix it.

Unfortunately, there's a MUCH WORSE (and STILL UNSOLVED) problem (reported in the same days of the liftoff drift issue by this Orlando Sentinel The Write Stuff article) called "burping" (from OS blog: "The trouble, engineers say, is that solid fuel rockets doesn’t always burn evenly and completely; they can fizzle out and then suddenly accelerate as residual fuel ignites. It’s called “burping”. The danger is that if this happens just as the stages separate, the first stage could suddenly accelerate and crash into the second stage carrying the astronauts, with disastrous consequences.") that can DOOM the full ESAS plan (since it may NOT happen this year in the planned Ares 1-X test, but ONLY in 2013, or later, when the first test launch of a real Ares-1, with the 5 segments SRB, a complete upperstage and an unmanned Orion, will be performed in the planned Ares 1-Y) if very serious (and complex to solve) design problems will be evidenced.

Just a bit less serious consequences will be, if the same problems will come to light in the Ares 1-X launch (especially if they'lle be easy to solve) while, if these problems can not be solved, that will mean "only" four+ years of time and a half-dozen Billion$ lost ... :(

However, as explained early in this article, my #1 concern about the Ares-1 design still is related to the "more mass than thrust" issue that seems CONFIRMED in the latest specs of the 5.5 segments SRB (published in this Flightglobal Hyperbola article).

As you can read in the NASA's document below, the real 5.5 segments SRB will have a 794 mT gross mass that's 35% HIGHER than a standard SRB 590 mT mass, while, the (expected but NOT yet really reached) 5.5 segments SRB thrust should be ONLY 26% HIGHER than a standard 4 segments SRB (15.8 MN vs. 12.5 MN) so, GREAT PART of the increased SRB thrust, will be necessary to lift itself rather than the Ares-5 payload!!!

The same will happen with the 5-segments SRB of the Ares-1 that (compared with the Ares-5 SRBs' specs) should weigh 24% MORE than a standard SRB and give 17% MORE thrust, that CLEARLY is a TOO LOW INCREASE to lift (both) the payload AND itself !!! 


My last concern (so far) about (both) 5 and 5.5 segments SRBs regards the boosters' INTERNAL PRESSURE that clearly will be 25% HIGHER in the 5-segments SRB of the Ares-1 and (at least) 37.5% HIGHER in the 5.5 segments SRB or the Ares-5 despite both motors will have the SAME CASE and the SAME JUNCTIONS of the standard SRB, so, my question is: Will the SAME case and junctions survive to the very much higher internal pressure OR they can/will LEAK (or explode) like happened with the Challenger?


[update] As clearly reported in this article, the Ares-1 staging can't work safely without the fundamental help of 20+ ULLAGE MOTORS that should separate the solid-propellent first stage motor (that can't be shut off) from the liquid-propellent second stage, so, the separation of the two stages, the full success of the mission and (also) the LIFE of the 4-6 astronauts aboard the Orion, depends ENTIRELY from the CORRECT WORK of these 20+ small (but fundamental) ullage motors!

Just imagine what may happen if part of these 20+ (fundamental!) ullage motors WON'T WORK properly and the, unstoppable but still burning, 1st stage motor will COLLIDE with the 2nd stage (full of cryogenic propellent) while the Ares-1 flies at hypersonic speed!!!

Or, what may happen if part of these 20+ ullage motors will burn accidentally while the Ares-1 hasn't yet reached the separation point/altitude or (worst) if one or more of these ullage motors will burn accidentally before the lift-off or while the astronauts are entering inside the Orion!!!

The most sounding claim of the Ares-1 inventors is that this rocket "should" be "two times safer and more reliable than an EELV" (thanks to its simple design) but, a claim like this "could" be true ONLY if we calculate the Ares-1 safety and reliability on failure risk of the two main stages' motor/engine, but, if we consider also the 20+ ullage motors (that are fundamental for the correct separation of the two stages, the success of the mission and the LIFE of the 4-6 astronauts aboard the Orion) the TRUE safety and reliability of an Ares-1 (clearly) can't be the claimed (and very poor) "two times than an EELV" but a (probably) 5+ TIMES LESS than an EELV since, the Ares-1, isn't "only" a "simple" one-motor/one-engine rocket, but, a (very much complex and unreliable) 21+motors/one-engine rocket and ALL of them MUST work properly to safely reach the given orbit!!!

 


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