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Thread: Space Launch System (SLS)

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    Space Launch System (SLS)

    Could not find a thread dedicated Space Launch System (SLS) so starting this one. The next major mile stone in it's development went successfully. That was the test firing of first RS-25 (unit E0525).

    http://www.nasaspaceflight.com/2015/...engine-firing/

    NASA’s Stennis Space Center has test fired the first RS-25 (unit E0525) of the Space Launch System (SLS) era on Friday, marking the beginning of a new career for the famous engine. Four of the former Space Shuttle Main Engines (SSME) are set to power each SLS during the ride to orbit, opening with Exploration Mission -1 (EM-1) in mid-2018.

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    Quote Originally Posted by selvaarchi View Post
    Could not find a thread dedicated Space Launch System (SLS) so starting this one.
    Actually there was, but it was before approval and full of debate of whether it would happen. But; years later (in 2014), was bumped with a post about approval.
    Since now it's a go, I think a fresh thread on its development without the debate is appropriate.


    The one question I have is that they mention a new adapter for the test stand. The A-1 stand used to be used for a variant of that engine before. So; is the old adapter just plain too old, already discarded, or are there some other testing or engine conditions the old one couldn't handle?

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    I guess nobody has an answer to my question.

    Along with that, I seem to not be getting any response to my booster question I posted on a UT thread.

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    Quote Originally Posted by NEOWatcher View Post
    Actually there was, but it was before approval and full of debate of whether it would happen. But; years later (in 2014), was bumped with a post about approval.
    Since now it's a go, I think a fresh thread on its development without the debate is appropriate.


    The one question I have is that they mention a new adapter for the test stand. The A-1 stand used to be used for a variant of that engine before. So; is the old adapter just plain too old, already discarded, or are there some other testing or engine conditions the old one couldn't handle?
    Quote Originally Posted by NEOWatcher View Post
    I guess nobody has an answer to my question.

    Along with that, I seem to not be getting any response to my booster question I posted on a UT thread.
    According to the article and this one, an new adapter is needed for each rocket engine. The RS-25 engines for the SLS are about 80% more powerful than the J-2X engines that were previously tested. Does that answer your question?

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    Quote Originally Posted by spjung View Post
    According to the article and this one, an new adapter is needed for each rocket engine. The RS-25 engines for the SLS are about 80% more powerful than the J-2X engines that were previously tested. Does that answer your question?
    No, because before the J-2 engines, they were testing the RS-25.
    Now; I know that the new engines will be a modified version of the SSME RS-25s, but I don't know what that is either. I saw references to say that it was modified for one-time use. But; that doesn't say much.
    Although, this article talks about a lot of welding needed. Maybe the adapters just can't be saved from one engine to another.

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    Quote Originally Posted by NEOWatcher View Post
    No, because before the J-2 engines, they were testing the RS-25.
    Now; I know that the new engines will be a modified version of the SSME RS-25s, but I don't know what that is either. I saw references to say that it was modified for one-time use. But; that doesn't say much.
    Although, this article talks about a lot of welding needed. Maybe the adapters just can't be saved from one engine to another.
    Ok, now I think I understand. NASA last tested an RS-25 in 2009, so maybe the old adapter was discarded or it was too worn out/too old to be reused. They still have 15 old engines that they're planning on using for the SLS. Then later they're going to build new engines designed for single-use.

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    I think I narrowed it down.
    The RS-25E is more powerful, and I found the following quote in one article
    The A-1 stand is currently undergoing modifications to accommodate the RS-25 engine and the new SLS conditions.
    So; it could be for the above reasons, but the quote also makes me think that they needed a bit more structure than the RS-25Ds anyway.

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    Questions on safety of flying astronauts on the system in 2021.

    http://www.parabolicarc.com/2015/02/...sk/#more-54531

    ASAP also expressed concerns about the risks to crew members on the first crewed flight of Orion scheduled for 2021. The report noted that Exploration Mission 2 (EM-2)

    will be the first full-up flight test of the new upper stage rocket motor as well as several critical life-support systems, including the Pressure Control System, the Air Revitalization System, and the Fire Detection and Suppression system. NASA has an extensive ground and flight test program planned to exercise these systems extensively before this flight test and to verify their design features. Included in this test program will be microgravity exposure on the ISS.

    However, NASA should give careful consideration to the unknowns that may be detected only by actual flight test of safety-critical Orion systems before exposing crew to the flight test regime. If NASA does indeed decide to fly crew on EM-2, the Panel urges NASA to be transparent with all stakeholders and the public on the risks involved, including the rationale supporting why crew are needed on this mission.

    ASAP noted that overall risks in programs are higher during early flights than they are over the course of a program. For example, in the space shuttle program

    actual risk during early flights was as much as 10 to 100 times greater than the analyses indicated. Early Shuttle astronauts actually faced a 1 in 10 probability of catastrophe on each flight rather than the 1 in 1,000 probability that some analyses had indicated….

    Because the perception of external stakeholders is vitally important, NASA’s Office of Communications must be cautious not to create or reinforce inaccurate perceptions of risk….

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    So they are concerned. Don't they think NASA is concerned?
    Historically;
    NASA's manned craft have never had a flight death in any of their programs until STS-51 which was already well into it's program.
    In fact, dangers to the astronauts on the ground have been just as deadly as in flight. An equal amount of astronauts died on the ground as in flight, and that was only in two flight accidents.

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    With an asteroid, you don't have to land, just "dock."

    So starting out with an asteroid and getting used to 'deep space" before a landing makes sense.

    I keep hoping J-2 will be used--but as upper stages of course.

    The low density high volume LH2 makes for a bigger rocket than falcon Heavy--and that translates into a larger shroud potentially.

    Both payload and mass constraints limited the size of Mars rovers.

    One launched atop SLS should be very capable.

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    SLS is huge be any standards. So the infrastructure to support it will also be huge. One example is the barge required to transport it.

    http://www.nasaspaceflight.com/2015/...ore-transport/

    The famous Pegasus Barge is nearing the end of its jumboisation phase, as work continues to prepare it for a role in transporting the massive Space Launch System (SLS) stages from their birth place the Michoud Assembly Facility (MAF). The upgraded Pegasus is set to transport the first major SLS hardware from New Orleans to the Stennis Space Center for testing as early as next year.

    One more example - this time work on Kennedy Space Center’s Pad 39B

    http://www.nasaspaceflight.com/2015/...rench-upgrade/

    One of the final upgrades to Kennedy Space Center’s Pad 39B will begin in earnest, following a deal between the Kennedy’s Ground Systems Development and Operations (GSDO) Program and J. P. Donovan Construction. The contract for a new Flame Deflector and associated Flame Trench work is required to help the pad deal with the immense thrust of the Space Launch System (SLS).
    Last edited by selvaarchi; 2015-Feb-08 at 03:04 PM.

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    Another small step in getting SLS ready for launch completed successfully.

    http://www.spacedaily.com/reports/Er..._Tank_999.html

    Goodbye, geysers! NASA engineers have successfully finished anti-geyser testing for the liquid oxygen tank that will help fuel the agency's new rocket, the Space Launch System, on the journey to Mars.

    More than 120 hours of anti-geyser testing have been completed on a full-scale, 40-foot replica of the SLS liquid oxygen tank feed system -- which will be housed in the rocket's core stage -- at one of the test stands at NASA's Marshall Space Flight Center in Huntsville, Alabama. The core stage, towering more than 200 feet tall with a diameter of 27.5 feet, will store cryogenic liquid hydrogen and liquid oxygen that will feed the vehicle's RS-25 engines.

    "Geysering occurs when heat enters the liquid oxygen feed system, causing the liquid to boil and form large oxygen gas bubbles that rapidly expel," said Chad Bryant, propulsion manager in the Stages Office at Marshall, where the SLS Program is managed for the agency.

    "This rapid expulsion of boiling liquid can momentarily displace large volumes of heavy liquid that crash back down, causing a damaging hammer effect on the system.

    "One of the largest risks with a liquid oxygen feed system of this scale is the potential of creating a geyser -- that's why this kind of testing is so important," he added. "This gives us the confidence that the operations we have in place for propellant loading, conditioning and draining will successfully suppress geysers in the system during flight vehicle operations."

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    Super Crawler CT-2 preparing for a test run to Pad 39B

    http://www.nasaspaceflight.com/2015/...t-run-pad-39b/

    NASA’s Crawler Transporter -2 (CT-2) is scheduled to be taken for a “quick” spin to Pad 39B at the Kennedy Space Center (KSC) this week, testing its latest modifications ahead of an active role with the Space Launch System (SLS). Both of NASA’s iconic Crawlers are being re-purposed for SLS, following their previous roles with the Saturn rocket and the Space Shuttle.

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    Here is one more proposal for SLS and Orion. Astronauts in Orion would control robotic missions on the moon.

    https://eos.org/features/human-robot...ns-moon-beyond

    Burns et al. [2013] outlined a plan to deploy robotic vehicles—a Moon lander—to Schrödinger basin that could be operated remotely by a crew in the Orion spacecraft. In this plan, Orion would hover above the Moon’s farside around Earth–Moon Lagrange position L2.

    Candidate landing sites with traverses, along which a rover would collect samples and return them to the ascent vehicle, have already been identified [Potts et al., 2015]. This vehicle would then rendezvous with Orion so that crew could return the samples to Earth.

    This mission would present technical challenges that scientists and engineers will need to solve as part of the redevelopment and expansion of capabilities to explore beyond low-Earth orbit. It would also demonstrate Orion’s capabilities to conduct long-duration operations, traveling 15% farther than Apollo and spending three times longer in deep space. It would practice teleoperation of rovers, which is an anticipated skill for future missions to Mars. It would also simultaneously address a majority of the NRC [2007] science objectives.

    This mission or a similar one could deploy an astrophysical observatory, another high-priority NRC [2010] objective, and a communications satellite for future robotic and human missions. Joint scientific and engineering studies continue with the hope that this integrated robotic and human mission will be the first of many milestones that enhance our ability to explore space.

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    Quote Originally Posted by selvaarchi View Post
    Here is one more proposal for SLS and Orion. Astronauts in Orion would control robotic missions on the moon.
    I don't see it happening anywhere in the foreseeable future. NASA already has a long term plan for Orion and it doesn't include such moon research.
    Besides, I see nothing here but a study, and not a proposal.

    I also don't see why the cost of a human mission is an advantage over purely robotic ones. The communication delay from Earth is already short and for sample return, you don't need such an advanced re-entry craft.

    Other countries are demonstrating that this kind of moon research does not need humans.

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    Quote Originally Posted by NEOWatcher View Post
    I also don't see why the cost of a human mission is an advantage over purely robotic ones. The communication delay from Earth is already short and for sample return, you don't need such an advanced re-entry craft.
    This reminds me of the earliest concepts for communications satellites...manned space stations with crews to flip switches, replace burned out tubes, etc.

    It's hard enough to justify for Mars, with its much larger delays. Robotics on the moon can be operated in near-realtime from Earth...this proposal has much of the costs and risks involved with actually sending people to the surface, without achieving any of the benefits of doing so. The manned element is included purely for the sake of having a manned element. The crew of a manned mission should be workers augmenting the work of the robots, not...mascots doing expensive and unnecessary stunts.

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    Quote Originally Posted by NEOWatcher View Post
    I don't see it happening anywhere in the foreseeable future. NASA already has a long term plan for Orion and it doesn't include such moon research.
    Besides, I see nothing here but a study, and not a proposal.
    What plan? after the manned test flight there's nothing but vague suggestions.

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    Nothing vague at all--it has been looked at before: http://area3.org/a/ares-v-applicatio...ebook-e66.html

    With R-7 the payloads had to wait for the rocket.

    I'd like to see JPL quit trying to kill SLS and design some Mars rovers to go atop it--something that could circumnavigate Mars, be large enough to roll over most obstacles, as explained here:
    http://www.wired.com/2014/02/mars-ro...re-phase-1988/

    Donna Pivirotto, MRSR Rover manager at JPL...lamented that “large ‘Godzilla’ rovers which simply roll over all obstacles would be precluded by launch vehicle mass and volume constraints."

    Those constraints have been done away with. Delta II was a crutch. A cheap crutch--but a crutch all the same.

    http://cosmoquest.org/forum/showthre...51#post2195851

    Attempts to ignore or undermine SLS are counter-productive.
    Last edited by publiusr; 2015-Feb-22 at 09:27 PM.

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    Quote Originally Posted by NEOWatcher View Post
    I don't see it happening anywhere in the foreseeable future. NASA already has a long term plan for Orion and it doesn't include such moon research.
    Besides, I see nothing here but a study, and not a proposal.

    I also don't see why the cost of a human mission is an advantage over purely robotic ones. The communication delay from Earth is already short and for sample return, you don't need such an advanced re-entry craft.

    Other countries are demonstrating that this kind of moon research does not need humans.
    Do not write off ideas so easily.

    Remember that NASA has signed on three companies to develop moon landers. Also NASA'S plan is to send Orion in the early 2020s with crew around the moon and bring them back to earth.

    Combining the two together, you just might get what the article was saying.
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    Next big test for SLS is on March 11.

    http://www.nasaspaceflight.com/2015/...id-future-sls/

    The previously delayed QM-1 test firing now remains on track for March 11, still well within the critical path schedule for the debut launch of SLS in 2018.

    The five segment version is a direct descendant of the four segment motor that pushed Space Shuttles through their first stage flight – boosters that were continually upgraded and improved right through to their final mission with STS-135.

    With the QM-1 motor now anchored into the ground at Orbital ATK’s test facility in Promontory, Utah – preparations for its big, noisy day included final checks on the flight-like avionics system that will be tested during the firing.

    While the test will produce a huge amount of data on the booster’s performance, the validation of the avionics system – responsible for igniting, steering and jettison of the boosters – will be critical.

    “We are designing a system for a human-rated vehicle that has to be at a minimum single-fault tolerant, which means no one failure on a critical system can result in a big problem for the mission,” noted Eric Corder, avionics system manager for the SLS Booster Element at MSFC.

    “We don’t want the rocket to just operate the way it’s supposed to. Our team intentionally implements failure scenarios to the electronics to make sure, for example, a shorted circuit or faulty box doesn’t compromise mission success. That’s even an issue that may have a one-in-10,000 chance of occurring.”

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    Although UT is part of the board, I figured it would be good to reference it "for the record" on the thread.
    Test successful
    Now we wait a year for the cold condition test. One that I think has less confidence (if only by a virtually undetectable margin).

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    If only development was progressing as fast as the booster will travel.

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    Well, folks have been calling for shuttle derived heavy lift for many years--the requests falling on deaf ears until now. What with all the hostility--I'd say they are going gangbusters.

    It is ahead of Ares I of course--and in many ways is just a scaled up hydrolox Atlas, minus the balloon tank. This could well be a stage and a half system--with perhaps the main body placed in orbit--an even larger version of Atlas Score.

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    The latest audit of the infrastructure to support SLS and Orion has flagged some concerns on the timing of the 3 projects and coordination between them.

    http://www.parabolicarc.com/2015/03/...nt/#more-54954

    NASA’s Office of Inspector General (OIG) has found that while NASA has been making steady progress on rebuilding Kennedy Space Center’s infrastructure for the Space Launch System (SLS) and Orion, the agency is facing significant challenges in completing the work in time for a planned November 2018 launch.
    “For the most part, these challenges originate from interdependencies between the GSDO, SLS, and Orion Programs, the report reads, referring to the Ground Systems Development and Operations program. “In short, GSDO cannot finalize and complete its requirements without substantial input from the other two Programs, and NASA is still finalizing the requirements for those Programs.”
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    NASA reveals its most powerful rocket launcher ever

    http://zeenews.india.com/news/sci-te...r_1574066.html

    The secondary payloads are Near-Earth Asteroid (NEA) Scout, Lunar Flashlight and BioSentinel.

    NEA Scout, using solar sail propulsion, will fly by a small asteroid, taking pictures and making observations that will enhance the current understanding of an the asteroid environment and will yield key information for future astronauts exploring an asteroid.

    NASA’s Lunar Flashlight will scout for locations on the lunar surface that are rich in resources that, once broken down into their component molecules, could be used in future exploration, such as building materials, propellant, oxygen and water.

    The BioSentinel mission will be the first time living organisms have traveled to deep space in over 40 years and the spacecraft will operate in the deep space radiation environment throughout its 18-month mission.

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    Reveal?
    SLS has been very well known for quite some time. What's revealed here is the secondary payload for it's maiden voyage.

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    Take a look at some of the quotes from here: http://www.thespacereview.com/article/2726/1

    The workshop, funded by The Planetary Society, is an indication that the organization best known for lobbying for robotic space exploration plans to take a bigger role in human spaceflight. “I’m excited to say that we’re re-engaging with the human spaceflight community:”That includes, he said, supporting the SLS, a launch vehicle that remains controversial in some parts of the space community. “When I first took the job [of Planetary Society CEO], I was under a lot of pressure to criticize the Space Launch System,” he said. “But it’s in the works, and the people doing it seem to know what they’re doing, and it really would be a great thing.”

    So even Bill Nye and The Planetary Society have--at last--come around.

    Nye said. “I say this about The Planetary Society, you guys: we are not crazy. We are not pie-in-the-sky people,” said Nye.
    http://forum.nasaspaceflight.com/ind...?topic=37254.0
    http://www.thespacereview.com/article/2725/1


    Some more links--about NextStep:
    http://nextbigfuture.com/2015/04/nas...is-to-get.html
    http://nextbigfuture.com/2015/04/nas...eep-space.html

    Quote from Gary Church:

    NewSpace proponents commonly libel the SLS as the “rocket to nowhere” while their favorite conveyance is actually the inferior lift vehicle. The SLS can deliver worthwhile payloads across cislunar space into lunar orbit. These payloads, in my view, are the building blocks of the next space age. Upper stage wet workshops and semi-expendable robot landers can be used to provide a true space station, shielded from space radiation generated by the worst possible solar events. The robots can land on ice deposits and take off with a load of harvested water, then transfer the water to workshops in lunar orbit- repeatedly. When this scenario is considered, it is the ISS that is a “space station to nowhere.” By adding a propulsion system to these fully shielded lunar space stations they become spaceships- quite unlike the ISS.

    http://www.americaspace.com/?p=79541

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    Quote Originally Posted by NEOWatcher View Post
    So they are concerned. Don't they think NASA is concerned?
    Historically;
    NASA's manned craft have never had a flight death in any of their programs until STS-51 which was already well into it's program.
    In fact, dangers to the astronauts on the ground have been just as deadly as in flight. An equal amount of astronauts died on the ground as in flight, and that was only in two flight accidents.
    We discussed that in February Post #8 & #9 and here we are in July and that is still a concern. This time with $$$ on the table. To make the Interim Cryogenic Propulsion System (ICPS) for SLS human rated, they will have to spend US150 million. Only to throw it all away after Exploration Mission -2. Now questions are being asked, why not go straight to Exploration Upper Stage (EUS) and save the money.

    http://www.nasaspaceflight.com/2015/...stage-dilemma/

    NASA officials have admitted the interim Upper Stage for the Space Launch System is at the top of their “worry list”, as the Agency’s key advisory group insists NASA should make a decision about bringing the more powerful Exploration Upper Stage (EUS) online sooner. The Aerospace Safety Advisory Panel (ASAP) fears NASA is at risk of wasting $150m on an Upper Stage they intend to “toss away”.

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    Quote Originally Posted by selvaarchi View Post
    We discussed that in February Post #8 & #9 and here we are in July and that is still a concern. This time with $$$ on the table. To make the Interim Cryogenic Propulsion System (ICPS) for SLS human rated, they will have to spend US150 million. Only to throw it all away after Exploration Mission -2. Now questions are being asked, why not go straight to Exploration Upper Stage (EUS) and save the money.
    We discussed this back in July. Now with Exploration Mission -2 most likely delayed by 2 years to 2023. Why not delay Exploration Mission -1 to include the more powerful Exploration Upper Stage (EUS).

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    That's the no-later than. The Delta IV upper stage is enough for circumlunar missions for now. All this just takes time. As it stands, SLS will be flying before any CZ-9 or BFR.

    It looks like solar electric will be the path to Mars:
    http://www.nasaspaceflight.com/2015/...issions-2030s/
    http://nextbigfuture.com/2015/09/new...isp-which.html

    Phobos mission http://www.nasaspaceflight.com/2015/...bos-mars-2039/
    https://www.youtube.com/watch?v=hNmXSsuf-KQ

    That's 28 years or less to Mars--not bad--and using current tech.

    Some musings from the web on Heavy Lift:

    "Another factor was that for an EELV class launch a spacecraft bound for Europa would need at least one Venus flyby. That would mean added thermal shielding and control. It has been done in the past with Cassini and Galileo. Making a spacecraft that will spend most of its life in the cold outer solar system able to hang out that close to the sun introduced design complexity and cost. A spacecraft near Venus would get almost twice the solar heat as one near Earth, and 52 times what it would receive at Jupiter."

    "Solar Probe Plus is $389 million. And even with a Delta 4-Heavy launch the mission will need seven flybys of Venus!?! Has anyone explored what SLS with an EUS could do to improve that? It's just a hypothetical... but an interesting one nonetheless."

    It's coming guys. Despite the naysayers who have done their dead-level best to kill SLS---no thanks to them.

    Now, were it up to me, SLS would be the **smallest** LV in America's stable of rockets:

    “Exploration-Class Rocket: A human-rated system with LEO throw-mass on the order of 200 mt, designed purposely for extremely high reliability and minimum operations cost, rather than being sized directly by an architecture that may change later,” noted the presentation. “200 mt, sized by ‘knee in the curve’ of LV economics. Not driven by the architecture de jour.”

    "No specific designs are included in the presentation, with a Saturn V schematic shown next to the 200mt references. However, such a vehicle would likely to be a three stage Ares V type heavy lifter."

    Ares V would have been the SSC to SLS' Large Hadron.

    But SLS is what is on the table.

    Still, after it flies another 30 or forty years (assuming I'm still alive) I will be pushing for Sea Dragon http://forum.nasaspaceflight.com/ind...310#msg1429310

    In the mean time, all who suggest Medium lift EELV class rockets or winged reusable craft (seeing how ho-hum Titans and the STS hobbled us in LEO for the 30 years we could have been on Mars) should be tied to the base of static test stands...
    Last edited by publiusr; 2015-Sep-26 at 06:19 PM.

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