We’re part of the team that helps NASA’s Orion slow down and splashdown. Ask us anything.

Could you give some info on why a water landing was chosen over land?

Does it save a significant amount of weight or is it just generally considered safer? Did recovery costs have any impact on that decision?

Mike Heckler and Chris Prouty: Water landings save weight. We conducted a trade study on this. We already had to have a water landing capability to provide an abort capability. Land Landing would require additional hardware that would not be used on water landings. Removal of the land landing hardware saved significant weight.

First of all, thanks so much for doing this. I believe we're at the beginning of a new cultural interest/excitement in spaceflight that sizzled out in the U.S after the tragedy of the Columbia disaster, and it's great to see this treated as a scientific (rather than military) endeavor to be shared with everyone.

Here are my questions:

1. It's my understanding that this test flight will be unmanned. Will there be any unique instruments that will be used to see that any potential crew would've survived, beyond heat/G force?

2. Does this mission have any objectives other than testing the viability of the rocket/spacecraft system?

3. Given that the LM Orion program and SpaceX share the specific goal of exploring deeper fields of space, do you see this as an opportunity for competition or collaboration?

Thanks so much!

1.) Correct, EFT1 will be unmanned. However, this flight has a large amount of instrumentation on it that will be used for post flight analysis and model correlation. Additionally, during some of our ground tests we do use instrumented anthropomorphic manikins.

2.) A couple major objectives that will be demonstrated on EFT1 is the performance of the Orion heat shield and performance of the Orion electrical system outside the Van Allen Belts. EFT1 will enter at ~19,000 mph and will reach an orbital altitude of 3,200 miles. In comparison, ISS visiting vehicles enter at ~12,000 mph and reach an orbital altitude of ~265 miles.

3.) I think most of us on Orion, as space geeks, enjoy watching the work that SpaceX does. We are focused on our responsibilities on Orion, but we know that as the community learns to better address challenges in space we will all benefit

Glad for this AMA! Thanks in advance for the answers! And may the Best Test Results be acquired on EFT1:)

1. Will you not upgrade Orion with an MLAS that will not be disposed off during launch but will be used as a propulsive landing module to terrestrial bodies in the solar system?

2. Is it possible to revived the Saturn V with a single F1 engine core and 4 single F1 engine strap on for future Orions?

3. Are there other options for a Multi Year Habitat Module for the Orion aside from the ISS Node, Cygnus or Inflatables type? Are composite or glass modules possible?

4. Is Pocket Fussion possible for the upgraded Orion Service Module?

5. How many Orions will be built? Will they be reused and up to how many times?

1.) this is an architectural decision that may be revisited down the road. But seldom is there a compromise that will effectively address two such different requirements (launch abort and lunar landing).

On your other point, we want Orion to go to the moon and Mars many times!

2.) With regard to Saturn V: At this point reviving Saturn V is really out of the question. The work going on now to develop and build SLS is a better use of our resources than restarting manufacturing lines, etc., to build something that has been surpassed by modern designs.

What kind of dangers are you able to anticipate, but have absolutely no contingency plan for?

Rick Here: Sorry for the delay, the team was talking through it. A very large space debris impact could be a very serious problem, it's hard to plan for an incident that catastrophically damages the whole structure of the spacecraft. It's why we plan as much as possible to avoid these kinds of incidents. Space travel is dangerous but we work to make it safer.

Are the fuels that a spacecraft uses considered scarce on the Earth? Countries seem to be launching a lot of stuff into orbit the last few years. Any danger the world runs out of launching fuel?

No, nearly all spacecraft use a mixture of liquid oxygen (LOX) as an oxidizer to help the fuel burn quickly and fiercely even in a vacuum. The fuel itself is usually either an alcohol/water mixture (good for low budget or smaller craft), or liquid hydrogen. There are also some more scenario-specific fuels, such as RP-1 (refined petroleum 1 and/or rocket propellant 1) which is used only for the first stage of the Saturn V.

The liquid oxygen and hydrogen can be refined from water through a process called electrolysis (I'm sure wiki has an article on it), so only petroleum based fuels have any danger of running out.

Great answer, thanks!

Okay, definitely my favorite AMA group member introduction ever, first off.

Secondly, what's your individual favorite sandwichs?

Thirdly, you guys are awesome. Seriously, you're doing the jobs I wanted to grow up and do most of my childhood. Alas, I'm a math major, not an engineer. But seriously, keep on being awesome.

Dan Hall: Everybody in here thinks math is awesome! It's essential for what we do. We use calculus, linear algebra, as well as modular & imaginary numbers.

Which universities did you all attend? My 8 year old is interested in this and already wants to go to Caltech. I would love to give him other ideas. Thx for your time!!

Rick: There are lots of great schools that you could attend. Caltech is certainly one of them, but pretty much all of the major universities have graduates involved in the space program, and lots of small schools as well. Here, as in many situations, diversity makes us stronger.

Chris Prouty: University of Colorado - Boulder Mike Heckler: University of Arizona Dean Coleman: University of Texas at San Antonio Dan Hall: University of Florida (Go Gators!!) Doug Harrison: University of Houston Rick Hieb: Northwest Nazarene University (then college)

To Rick - what's re-entry truly like, and do you have any memorable experiences from launch or re-entry?

To the team - first, as an aerospace engineer, thank you for helping get us back to large-scale human exploration. I've heard that the diameter of the capsule is smaller than it was originally planned, did that affect engineering decisions for you all?

re-entry on Shuttle was very smooth - gradual onset of gravity, very gentle. Scary outside the window because the heating is obvious, but inside quite calm.

Rick, what is the most harrowing part of being in space?

most harrowing part - launch is the scariest, but that is not really being in space, but getting there. Second is re-entry, because again that is a very dynamic part of the missions. Third would be a spacewalk - but it is so awesome that you are too busy working and sneaking looks at the earth to be scared (much!)

Dean Coleman: Since we've been working on Orion the capsule has remained the same size. So this wasn't a consideration for us

How are the parachutes for the orion capsule packed? Are they done by a machine or by hand?

Chris Prouty: Some of the smaller parachutes are packed by hand but the large main and drogue parachutes use hydraulic presses.

What is the best thing you all have ever seen in space?

From our engineers: Seeing our own hardware in Space is always an inspiring moment. We've all had moments with family and friends where we jump up and shout "that's my stuff"

From Rick: Earth

What's it like to be in space and look around you? What goes through your mind?

This is a tough question. It is a little like asking someone to describe being on a boat to someone who has always kept their feet on dry land, or describe being cold to someone who has always been warm. The best that I can come up with is that the view out the window is somewhat like the view out of an airliner window, just from much higher. An airliner flies up to 7 miles up, we are anywhere from 150 to 300 miles up. So we are a lot higher, but it is a difference in degree more than a difference in kind. The other primary sensation is that of weightlessness. The best analogy to this is only applicable if you are an adept swimmer, and very comfortable in the water. If you are, then being is space is a little like floating in the water of a warm swimming pool on a pleasant day. That is, the sensation of floating is one of relaxation and comfort, with no fear of falling or anything of the sort. I really miss floating!

Hi guys. I'm a mechanical engineering (aerospace focus) in her final year of school. I can pin point the moment I choose engineering when I saw Discovery launch in 2009. I want to thank you for working on the Orion program because it keeps me inspired about my field even during the worst exam weeks.

So for my question(s): how does the Orion program divide between the private sector (Lockheed Martin and other business) and NASA? And will Lockheed Martin continue to work on the program until it's end?

And any advice for this future engineer on the transition from university to the job market?

Mike Heckler: Space is a community. Contractors and NASA work together closely. NASA decides what work to perform in-house and what work they want contractors like us to perform. Then NASA then holds competitions and selects who they want to perform the work and awards a contract. As for transition from university to the job market, I'd advise trying to get to know someone in the industry, someone who can vouch for you always helps with getting your foot in the door. BTW, I fell in love with the space biz, after I saw the movie "The Right Stuff"! If you haven't seen it you should!

I am an Embry-Riddle student and was wondering how much does the Orion capsule weigh and what is it made of/how thick is the material to ensure it reaches Earth's surface safely?

Dean Coleman: Landed weight is ~ 19,500lbs. Launch weight is ~ 22,000lbs. The vehicle is comprised of many materials for thermal protection and metals for structures (titanium, aluminum, etc). The material thickness is as minimal as possible to achieve positive margin. Orion loses weight because because of things like fuel use, jettisoning of forward bay cover (parachute cover), and some ablative material coming off of the heat shield.

I hear there's a test launch in December. What's being testing this time around? How many test launches are planned?

With this test we’ll address 10 of our top 16 design challenges associated with deep space travel. We’ll test every inch of the spacecraft, from the aluminum lithium frame to the avionics and everything in between. This test is as comprehensive as it gets.

There are three test launches planned. EFT-1, EM-1 and EM-2.

What gives you drive?

Rick: making a difference today, and for future generations.

What makes Orion a truly "deep space" mode of transportation?

I would think that on any long-term journey, an additional habitation module would be included, so the radiation shielding on the capsule itself wouldn't necessarily need to be better. Is it just the heat shield for higher re-entry speeds?

Thanks for the AMA!

Dan Hall: Many many systems! An ablative heat shield, radiation proof avionics, a solar array and battery power system. In addition, advanced life support systems, communication and navigation support beyond the bounds of GPS, astronaut protection during deep space return velocities and protection from exposure to the harsh radiation present beyond low Earth orbit. It's also the most airtight vehicle that NASA has ever had!

Thank you so much for doing this AMA! I get to go to the ULA center in Denver and with the Rocket launch from there! My question is, what is the best thing a 17 year old looking to get into Aerospace Engineering do?

Rick: Work hard to get great grades, because it is a very competitive field. But don't just focus on school. Get broader experiences, take up SCUBA diving, flying airplanes, playing sports, etc. And learn to change your own oil and your tires on your car - astronauts do a lot with their hands, and engineers have to know about real hardware, so all those things help.

Hello, and thank you for hosting this AMA!

At what point do you expect Orion to go through maximum stress and heating during the reentry process? How does this point compare with the much faster return trajectories that would be experienced from the Moon and Mars?

Doug Harrison: We don't have an exact answer. That'd be a question for the aerothermal team, we're more focused on what happens during and after parachute deployment and on how to keep the spacecraft sealed and powered.

As someone aspiring to become an aerospace engineer, I have a couple of questions:

1. Do you think the concept of using a mass driver/Railgun as a method or launching spacecraft is fact, or fiction?

2. (An extension from Q1) Do you think that the idea of kinetic bombardment (Releasing a projectile from outer space, using gravity to give it Gravitational / kinetic energy) is going to be arriving in the near future?

3. When you are in space, Do you prefer looking out onto the earth, or towards the outer planets?

Rick: when you are in space - earth is way more interesting than the other planets. The other planets look pretty much the same as they do from a mountain at night -- we're really not THAT much closer. But earth -- it is just hard to talk about it without exceeding the available space here.

For Rick: have you seen Interstellar? If so, did you feel it portrayed the feeling of being in space accurately?

Interstellar -- I haven't seen it yet, but I will. My wife and I were discussing going to see it this weekend but it was too cold and nasty out so we stayed in instead!