International Space Station – Rocketology: NASA’s Space Launch System

Happy (Earth-) Independence Day!

On Monday, the United States celebrated the Fourth of July. Fireworks and backyard grills were ignited across the country.

A couple hundred miles above us, the International Space Station orbited Earth with two spacecraft attached to it.

What do these two things have in common? A quest for independence.

The Fourth of July, of course, is the United States’ Independence Day, celebrating the anniversary of the 1776 signing of the Declaration of Independence, announcing that the former colonies were becoming a sovereign nation.

The International Space Station is an early, but prominent step in NASA’s effort to achieve “Earth independence” in human deep-space exploration, a key part of our Journey to Mars. On the station, we are learning how to live off the Earth by conducting investigations to learn how the human body adapts to space and testing new technologies needed for longer missions. However, the two spacecraft docked to the space station demonstrate that our human spaceflight operations today are “Earth dependent.” While astronauts float freely in the microgravity aboard the station, they remain tethered to our planet by a supply chain of provisions needed to survive. Deliveries of food, science experiments, spare parts and gifts from home arrive and depart by spacecraft on a regularly scheduled basis. Earlier this year, the number of docked spacecraft reached six: American Dragon and Cygnus cargo ships, and Russian Progress cargo ships and Soyuz crew vehicles. Should something go wrong, the return to Earth is only a short distance away.

A Dragon capsule is being berthed to the International Space Station — American Dragon and Cygnus spacecraft can be seen here at the International Space Station, joining Russian Soyuz and Progress vehicles.

In order to travel to Mars, astronauts will have to survive without that tether. When they depart Earth, they will sail into the void of space without the comfort of frequent visits from resupply ships. They will have no quick return; should something break or go wrong, Earth is potentially more than a year away. These pioneers will rely on themselves and what they have with them, or what has been sent ahead. They will be the first to be independent of our home planet, with both the freedom and responsibility that carries with it.

Significant challenges await us as we move from Earth dependence into Earth independence, learning to operate in space in a way we never have before. To accomplish this, we will carry out “proving ground” missions – missions where we will, innovate, test, and validate new systems and capabilities that will help us learn to live longer and farther away from home. The first launch of the Space Launch System (SLS) rocket with the Orion crew vehicle will mark our entry into this proving ground era, relying on new systems farther from Earth than any human spaceflight mission has ever ventured. SLS and Orion will allow us to launch habitats and other equipment that will support the first astronauts to not only visit, but to live in deep space around and beyond our moon.

A spacecraft approaches Mars and its moons — Astronauts in deep space will need to be able to survive without frequent resupply missions from Earth or being able to return quickly to Earth.

When we have demonstrated the ability to live and thrive in deep space, the time will come for the first mission to leave the neighborhood of the Earth and moon and extend human existence into the solar system, a mission that will not only be a major step toward human landings on Mars but will be our declaration of Earth-independence.

In that moment, the word “Independence” will designate the time when humankind became an interplanetary species.

Get the grills and fireworks ready, because that will be an occasion to celebrate.

Next Time: A Real-World Space Lesson

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The Rocket Comes to the Rocket City

By David Hitt

Over the next year, the rocket comes to the Rocket City in a big way.

Huntsville, Alabama, a.k.a. “Rocket City,” is home to NASA’s Marshall Space Flight Center, where today the Space Launch System (SLS), the powerful rocket NASA will use for human exploration of deep space, is being developed.

More than six decades ago – before NASA even existed – Huntsville laid claim to the nickname thanks to its work on missiles and rockets like the Juno that launched the first American satellite or the Redstone used for the first Mercury launches.

In the years since, Huntsville, and Marshall, have built on that legacy with work on the Saturn V rockets that sent astronauts to the moon, the space shuttle’s propulsion systems, and now with SLS.

New test stand at Marshall Space Flight Center — A steel beam is “flown” by crane into position on the 221-foot-tall (67.4 meters) twin towers of Test Stand 4693 during “topping out” ceremonies April 12 at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

While the program is managed at Marshall Space Flight Center, contractors around the country are building the rocket. Engines are being tested in Mississippi. The core stage is being built in Louisiana. Booster work and testing is taking place in Utah. Aerospace industry leaders and more than 800 small businesses in 43 states around the country are providing components.

The Marshall team has also been involved with the hardware, largely through testing of small-scale models or smaller components. The center also produced the first new piece of SLS hardware to fly into space – a stage adapter that connected the Orion crew vehicle to its Delta rocket for Exploration Flight Test-1 in 2014 (See Orion’s First Flight for more.) The same adapter will connect Orion to SLS for their first flight in 2018.

The top half of a test version of the SLS Launch Vehicle Stage Adapter on a weld tool at Marshall — Workers prepare the top half of a test version of the SLS Launch Vehicle Stage Adapter. The completed adapter will undergo structural testing at Marshall later this year.

Now, however, big things are happening in the Rocket City. The new Orion stage adapter for the upcoming launch is being built. The larger Launch Vehicle Stage Adapter, which will connect the core and second stages of the rocket, is being built at Marshall by contractor Teledyne Brown Engineering. This year, test versions of those adapters and the Interim Cryogenic Propulsion Stage (ICPS) will be assembled into a 56-foot-tall stack, which will be placed in a test stand to see how they handle the stresses of launch.

Those test articles built locally will be joined by larger ones produced at the Michoud Assembly Facility outside New Orleans. Test versions of the rocket’s engine section, oxygen tank and hydrogen tank will be shipped by barge from Michoud to Marshall. Two new test stands – one topped out last month at 221 feet tall – have been built at Marshall, joining historic test stands used to test the Saturn moon rockets.

The Payload Operations Center at Marshall Space Flight Center — In addition to rocket development, Marshall is involved in numerous other efforts, including supporting all U.S. scientific research conducted aboard the International Space Station.

Fifty-five years ago this month, Alan Shepard became the first American in space riding on a Redstone rocket, named for the Huntsville army base where his rocket had been designed – Redstone Arsenal. Today, Marshall, located on the same red clay that gave the arsenal and rocket their name, is undertaking perhaps its largest challenge yet – building a rocket to carry humans to the red stone of Mars.

Huntsville grew substantially from its small Southern town roots during its early days of rocket work in the 1950s and ‘60s, and Marshall has gone on to be involved in projects such as Skylab, Spacelab, the Hubble Space Telescope and the International Space Station, to name a few. But despite branching out its work both in space and other technology areas, Huntsville remains the Rocket City.

…After all, we built this city on a rocket role.

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#YearInSpace: Mars, Miles, Months, Mass and Momentum

During his yearlong mission aboard the International Space Station, Scott Kelly traveled over 143 million miles in orbit around Earth.

On average, Mars is 140 million miles away from our planet.

Coincidence? Well, basically.

Scott Kelly with plant-growth experiment — NASA astronaut Scott Kelly took this selfie with the second crop of red romaine lettuce in August 2015. Research into things like replenishable food sources will help prepare the way for Mars. (And the red lettuce even kind of matches the Red Planet!)

There’s nothing average about a trip to Mars; so of course you don’t travel an “average distance” to get there. Launches for robotic missions – the satellites and rovers studying Mars today – are timed around when Earth and Mars are about a third of that distance, which happens every 26 months.

While the shortest distance between two points is a straight line, straight lines are hard to do in interplanetary travel. Instead, Mars missions use momentum from Earth to arc outward from one planet to the other. The Opportunity rover launched when Earth and Mars were the closest they’d been in 60,000 years, and the rover still had to travel 283 million miles to reach the Red Planet.

On the International Space Station, Scott Kelly was traveling at more than 17,000 miles per hour, an ideal speed for orbital research that keeps the station steadily circling Earth every 90 minutes. To break free of orbit and go farther to deep space, spacecraft have to travel at higher speeds. Opportunity, for example, traveled at an average of 60,000 miles per hour on the way to Mars, covering twice the distance Kelly traveled on the station in just over half the time.

Graphic showing Opportunity’s trajectory from Earth to Mars — Although Earth and Mars were relatively close together when Opportunity launched, the rover’s trip out was twice the average distance between the two planets.

The fastest any human being has ever traveled was the crew of Apollo 10, who hit a top speed of almost 25,000 miles per hour returning to Earth in 1969. For astronauts to reach Mars, we need to be able to propel them not only faster than the space station travels, but faster than we’ve ever gone before.

But the real lesson of Kelly’s year in space isn’t the miles, it’s the months. The human body changes in the absence of the effects of gravity. The time Kelly spent in space will reveal a wealth of new data about these changes, ranging from things like how fluid shifts in microgravity affected his vision to the behavioral health impacts of his long duration in the void of space. This information reveals more about what will happen to astronauts traveling to Mars and back, but it also gives us insight into how to equip them for that trip, which will be approximately 30 months in duration round-trip. What sort of equipment will they need to keep them healthy? What accommodations will they require to stay mentally acute? What sort of vehicle do we need to build and equip to send them on their journey?

Months and millions of miles. Momentum and mass. These are some of the most basic challenges of Mars. We will need to build a good ship for our explorers. And we will need the means to lift it from Earth and send it on its way fast enough to reach Mars.

An engine section weld confidence article for the SLS Core Stage is taken off the Vertical Assembly Center at NASA's Michoud Assembly Facility in New Orleans — An engine section weld confidence article for the SLS Core Stage is taken off the Vertical Assembly Center at NASA’s Michoud Assembly Facility in New Orleans.

While Scott Kelly has been living in space helping us to learn more about the challenges, we’ve been working on the rocket that will be a foundational part of addressing them. Scott Kelly left Earth last year half a month after the Space Launch System (SLS) Program conducted a first qualification test of one of its solid rocket boosters. Since then, we have conducted tests of the core stage engines. We’ve started welding together fuel tanks for the core stage. We’ve begun assembling the upper stage for the first flight. We’ve been building new test stands, and upgraded a barge to transport rocket hardware. The Orion program has completed the pressure vessel for a spacecraft that will travel around the moon and back. Kennedy Space Center has been upgrading the facilities that will launch SLS and Orion in less than three years.

And that’s just a part of the work that NASA’s done while Kelly was aboard the space station. Our robotic vanguard at Mars discovered evidence of flowing liquid water, and we’ve been testing new technologies to prepare us for the journey.

Down here and up there, it’s been a busy year, and one that has, in so many ways, brought us a year closer to Mars. The #YearInSpace months and millions of miles may be done, but many more Mars milestones are yet to come!

Next Time: Next Small Steps Episode 3

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