posted 07-11-2011 06:45 AM               

Please use this topic to discuss the Space Launch System (SLS) as NASA develops the new heavy lift launch vehicle.

posted 09-14-2011 09:16 AM               

NASA Announces Design for New Deep Space Exploration System

NASA is ready to move forward with the development of the Space Launch System — an advanced heavy-lift launch vehicle that will provide an entirely new national capability for human exploration beyond Earth's orbit. The Space Launch System will give the nation a safe, affordable and sustainable means of reaching beyond our current limits and opening up new discoveries from the unique vantage point of space... [continue reading]

posted 09-14-2011 10:29 AM               

And while SLS's side-mounted boosters will may start off as space shuttle solid rocket motors during development flights, their ultimate design will be competed and could end up being liquid-fueled rockets.

As an aside, Sen. Bill Nelson noted during the press conference this morning that the images released so far are of the "smaller" 70 metric ton (mT) version.

posted 09-14-2011 11:12 AM               

quote:

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Originally posted by issman1:
It should be a liquid-fueled system from the outset

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"It's initially solid rocket motors for potentially the first or second test flights and then we'll go compete those boosters and they could be any type of propellant," he said.

quote:

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At least that awfully big launch tower at KSC will be used

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posted 09-15-2011 03:09 AM               

quote:

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Originally posted by issman1:
NASA just cannot let go of the past and wants to persist with solid rocket boosters, commercially or integrated into this heavy lifter.

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There is nothing wrong with using solids. More people have flown in space on solid fueled first stages without a problem than other systems. There have been some minor issues since Challenger, but they were dealt with successfully at the first signs of trouble (i.e. O-ring erosion, such as what was seen in the mid-1990s).

Secondly, except for Challenger, no shuttle based solid has ever failed or lost thrust. Even on Challenger, when the O-ring issue was brought up, the Thiokol engineers who brought it up thought the likely result would be the solid would completely fail at SRB ignition and destroy the stack on the pad. That didn't happen and if anything the "flawed" solid kept working for far longer than it was expected.

There are less moving parts in a solid than a liquid engine. Turn them on and they burn. As long as the casing doesn't have a defect in it (ala the Delta rocket that exploded in the 1990s) things should be fine. A liquid motor has all sorts of little things that could go wrong as you have fuel inlet pipes, turbopumps, cooling jackets on the engine bells. Plus, you have the need for both a fuel and an oxidizer to flow properly because if one gets blocked, you have no engine. Just ask the Russians about that and their Soyuz rocket which lost a Progress recently. That was a stage 3 failure likely caused by a blockage in a pipe. But a few years ago, another Soyuz rocket with a Foton M-1 satellite had an engine failure on a stage 1 strap-on right at the critical point just after launch. It went up, then came down 15 seconds later resulting in a nice BIG fireball on the pad.

posted 12-07-2011 01:01 PM               

The maiden flight of SLS is scheduled for 2017. In its debut, a 70-metric-ton variant of the rocket will boost an unmanned MPCV to the Moon and back. A second flight in 2021 would aim to repeat the feat with a crewed MPCV. Both launches would feature an SLS with a core stage powered by a cluster of four or five RS-25D engines Pratt & Whitney Rocketdyne originally built for the space shuttle.

NASA recently proposed adding $130 million to Pratt & Whitney Rocketdyne’s $1.5 billion J-2X contract to cover work the company would need to do to support use of the existing RS-25D engines for four or five initial SLS flights.

Because NASA is anticipating flat budgets for SLS for the next several years, the agency now plans to put J-2X development on a four-year hold after a battery of tests on the engine wrap up some time in the 2013-2014 timeframe, Stanfield said.

posted 12-12-2011 05:33 PM            

My point is that you don't build a massive rocket if you only plan to fire it once every four years. That's economic and engineering lunacy. Unless each individual rocket is a unique hand-crafted work of art, there has to be a production line producing components, with workers punching their cards every morning at the factory, expecting to have work to do.

If you only produce one rocket off your assembly-line every four years, your skilled managers and engineers will drift away to other jobs. The enhanced ability which emerges from doing a skilled job regularly will dissipate.

posted 12-12-2011 05:43 PM               

Given the constrained funding available, NASA was asked to develop a flight plan that could realistically fit within that budget. Not building the Space Launch System and going a different direction was not an option (it was mandated by law) so the schedule as released prevailed.

posted 09-05-2013 04:55 PM               

The Space Launch System (SLS) will be the next heavy-lift launch vehicle for the National Aeronautics and Space Admin. (NASA, Washington D.C.). Composites have been chosen for both the launch vehicle structures and tooling because they offer performance and cost advantages over metals.

As part of a three-year program to develop and demonstrate composite tooling and fabrication technology, Janicki Industries (Sedro-Woolley, Wash.) began working with NASA in 2010 to design tooling for a 1/6th-arc SLS fairing segment. Each segment measures 8.5m by 5.5m (28 ft by 18 ft), and six of them will be assembled to form the barrel section of the payload fairing for the SLS launch vehicle. NASA's objective was to demonstrate that cost-effective production of a lightweight composite structure is possible. "Our capabilities lined up well with NASA's goals in this program," explains Matt Robson, project manager at Janicki, "including out-of-autoclave processing, fabrication of large-scale tooling and pioneering of new processes to meet unique project demands."

posted 02-09-2014 09:32 AM               

At last update, NASA does not plan to recover the boosters used with the Space Launch System as a cost saving measure.

posted 08-27-2014 02:18 PM               

[Key Decision Point-C] provides a development cost baseline for the 70-metric ton version of the SLS of $7.021 billion from February 2014 through the first launch and a launch readiness schedule based on an initial SLS flight no later than November 2018.

"We will keep the teams working toward a more ambitious readiness date, but will be ready no later than November 2018," said William Gerstenmaier, associate administrator for the Human Explorations and Operations Mission Directorate at NASA Headquarters in Washington.

posted 10-24-2015 03:15 PM               

For the first time in almost 40 years, a NASA human-rated rocket has completed all steps needed to clear a critical design review (CDR). The agency's Space Launch System (SLS) is the first vehicle designed to meet the challenges of the journey to Mars and the first exploration class rocket since the Saturn V.

...also as part of the CDR, the program concluded the core stage of the rocket and Launch Vehicle Stage Adapter will remain orange, the natural color of the insulation that will cover those elements, instead of painted white.

posted 10-24-2015 03:19 PM               

The color scheme though, offers a visual hook by which to report the completion of the CDR.

posted 12-05-2015 05:46 PM            

Obviously the external tank of the space shuttle needed the foam to prevent the build-up of ice (which would have fallen on the orbiter, causing tile-losses). But the Saturn V didn't need insulation foam and, like the Saturn V, there is no orbiter strapped to the side of the SLS core.

posted 12-05-2015 06:13 PM               

The primary purpose of the foam was/is to maintain the cryogenic temperatures inside the tanks needed to keep the hydrogen and oxygen liquid.

Ice formation was a concern during shuttle, but wasn't the only or driving need for the foam insulation. Here is how NASA described the foam for the shuttle external tank:

The closed-cell foam used on the tank was developed to keep the propellants that fuel the shuttle's three Main Engines at optimum temperature. It keeps the shuttle's liquid hydrogen fuel at minus 423 degrees Fahrenheit and the liquid oxygen tank at near minus 297 degrees Fahrenheit — even as the tank sits under the hot Florida sun — while preventing a buildup of ice on the outside of the tank.

posted 05-10-2017 04:36 PM               

Kim Henry, a spokesperson for NASA's Marshall Space Flight Center, said May 10 that NASA and Boeing, the prime contractor for the SLS core stage, have established independent investigation teams to review an incident at Michoud one week earlier involving the rear dome of a liquid oxygen qualification tank.

...The agency didn't provide additional details about the incident, which took place in the Vertical Assembly Center at Michoud, used to weld large components of the SLS. The Vertical Assembly Center was shut down when the incident took place, Henry said. "NASA is evaluating next steps to safely resume operations."

The damage was limited to the one dome section of the tank, which was not yet welded to the rest of the tank. "Assessments are ongoing to determine the extent of the damage," she said.

posted 08-30-2017 09:25 AM               

Animation depicting NASA’s Space Launch System, the world's most powerful rocket for a new era of human exploration in deep space. Black-and-white checkerboard targets on the exterior of the SLS heavy-lift rocket will enable photogrammetrists to measure critical distances during spaceflight, including booster separation from the core stage.

posted 06-15-2018 08:39 AM               

Since the test flight of SpaceX's Falcon Heavy launch vehicle a few short months ago, many have questioned why we need SLS when commercial vehicles boast "bargain" prices. Their arguments center on the price-per-pound to orbit of commercial vehicles compared to SLS. However a price-per-pound comparison is practically meaningless in the context of real deep space mission requirements.

We need to launch crew along with the systems and supplies needed to support human life for longer than a couple of days in order to begin building our next "home away from home" in deep space. Depending upon location we will also need to launch a lot of infrastructure. For example, if lunar resources are to be used to support terrestrial fusion power, lunar settlement, and Mars exploration, large scale production and refining equipment and habitat and power facilities will be required.

SLS is designed to evolve to meet these needs. For purposes of comparison, let's assess just the current capabilities of SLS and SpaceX's Falcon Heavy in the context of each of deep space mission requirements...

posted 06-15-2018 10:39 AM               

quote:

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Originally posted by cspg:
Why do we need to launch crew and cargo together?

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posted 06-15-2018 09:22 PM               

For purposes of comparison, let's assess just the current capabilities of SLS and SpaceX's Falcon Heavy in the context of each of deep space mission requirements...