Different vehicles – different purposes: Orion and the Commercial Crew contenders
NASA has multiple tasks laid out in front of it. One of these is to empower an array of commercial firms to develop spacecraft designed to ferry crews and cargo to the International Space Station (ISS ). The space agency meanwhile is, in collaboration with Lockheed Martin, in the process of preparing the Orion Multi-Purpose Crew Vehicle ready to carry out crewed missions far beyond Earth’s gravitational influence. These are two distinct endeavors, with the spacecraft being developed to carry them out are specifically designed to handle the missions they are tasked with carrying out. In so doing, NASA is working on distinctly different vessels – designed almost exclusively for the challenges laid before them.
NASA is poised in the coming days or weeks to select the company which will carry out the next phase of the Commercial Crew Program (CCP ) and Orion is set to conduct its first flight in about two months time. These different spacecraft have different roles to play in the expanding effort to maintain the U.S.’ low-Earth-orbit operations as the space agency takes its first steps beyond Earth orbit – in more than four decades.
Orion is designed to send four to six astronauts atop the heavy-lift Space Launch System (SLS) booster to destinations such as an asteroid or Mars (The Obama White House has shown little interest in lunar missions). Before its first planned flight on SLS in 2018, Orion is slated to take to the skies this December atop a United Launch Alliance Delta IV Heavy rocket. To allow Orion to journey beyond LEO, it must have very specific capabilities which will allow it to venture into the far more dangerous environs beyond LEO.
To find out more about the requirements in terms of mass, radiation protection, avionics and the spacecraft’s heat shield, SpaceFlight Insider spoke with NASA’s Orion Program Manager Mark Geyer. Geyer relayed how Orion has been developed to be able to ferry crews of up to four astronauts to deep space destinations – for periods of up to 21 days.
SpaceFlight Insider: We know you’re a busy man Mark, thanks for taking the time to chat with us. Can you tell us a bit about what makes Orion suited to carry out missions beyond Earth?
Geyer: “No problem, there are a couple of key things that are important in terms of Orion. The first is the mission length, in terms of getting to the space station, it’s a couple days up and then one down. Right? Very short. For us it’s 21 days. Twenty-one days drives the consumables, so oxygen, carbon dioxide removal – those kind of things.
So what does that mean? It’s a volume thing, tanks, stowage, food and all of those kind of things are a lot different for a 21 day mission. One good example would be, you know, on a short mission, you could certainly use LiOH (lithium hydroxide) canisters, in fact we’ve done that in the past. For like four people, if you’re going to fly LiOH cans, it’s like 150 pounds per week, so if you go three weeks it’s 450 pounds, plus you got all of the volume that goes with that.
That really requires us to find a more elegant way to get rid of the CO2, we have this, what we call a mean swing bed, which basically absorbs the CO2 and then you swing the bed to expose it to a vacuum and it basically gets rid of the CO2 and then you swing it back. It’s a technology development that NASA had to do to really save the mass.”
SpaceFlight Insider: What else can you tell us about Orion that differentiates it from a spacecraft that only needs to travel to LEO?
Geyer: “One of the big things to consider is distance. The space station is 260 miles away, the Moon is 240,000 miles – so a lot more Delta V (Delta Velocity – The change in velocity required to get from one orbital state to another) is required and then a lot more propellant needed to come home from that distance too. So, for example, you’d probably need about double the propellant needed for a LEO mission when you think about rendezvous and docking and all of that kind of stuff, so double, maybe 20,000 lbs (9,072 kilograms) total. So you need a lot more prop, your service module is bigger – that sort of thing.”
SpaceFlight Insider: Given the amount of energy you would build up on a mission just to the Moon, you would need a spacecraft that is designed to handle the extremes that such a trip would place on it – is this an accurate assessment?
Geyer: “You’re hitting on a really important point there – think about the velocities needed. So, we’re going to need to be at 11 kilometers (7 miles) a second, that kind of thing, right? When you’re coming back from LEO – you’re at about 7 kilometers (4 miles) per second – so it’s quite a bit different and actually when you get into those higher velocities, an interesting thing happens, where this shock layer, this radiated heating from the shock layer – is a dominate driver for the heat loads that you are seeing. So it kind of changes the physics as you go further into space.
This is different than if you’re just arriving back from LEO, your TPS (thermal protection system) has to be able to deal with that and, for us, this AVCOAT was chosen to be the best for that mission. You can certainly use PICA (another material used in heat shields) for a lunar mission. For our particular case, when we looked at it and its velocities – there was a lot of concern about these gap-fillers that you need for PICA blocks. There was concern that they wouldn’t recess at the same rate that the PICA did. That causes hot spots and other things.
So, for the NASA team that did the study, which was independent from Orion, we felt that for a lunar re-entry and for the manufacturing and other things – we felt that AVCOAT was the best solution.
The arc jets that we use to certify TPS systems for entry do not currently have the capability to certify anything above LEO entry. So, we are actually funding the upgrade at Ames to do that certification. Until that happens, no one would actually be able to certify a heat shield beyond LEO entry.
When the speed is greater, it affects the ablation rates – so that would affect the thickness of the heat shield that you would need and it even affects the certification that you would need to do on the ground. Ours has done that. So Orion has a heat shield specifically designed for those re-entry velocities and it will been certified for that.”
SpaceFlight Insider: Orion must also have systems designed to handle the increased radiation found in deep space as well…
Geyer: “Correct, spacecraft that travel beyond LEO are going to encounter a much more severe space environment than those that only travel to LEO. Orion is going to go through and outside the Van Allen belts. So we have a large increase in ionizing radiation – this affects not only the crew – but the avionics as well.
Your avionics need to be hardened and you need to do a lot of analysis and testing. Moreover you need to have redundancy to get the crew home safely. So that’s a big driver for our avionics.
Also, if there is a solar particle event – we need to be sure that we can get the crew into a safe position. In other words, we need to have an area and a way to use the stowage equipment, the water and other elements of Orion so as to provide a barrier for them. That takes up volume in the spacecraft – which you wouldn’t need to worry about in a LEO spacecraft.”
SpaceFlight Insider: Can you tell us a bit more about what other elements that Orion has to protect crews against radiation in deep space environments?
Geyer: “The big thing is the spacecraft’s primary structure, but also any of the stowage equipment has some shielding capability. These materials…some are better than others. We’re not going to fly any special materials, any special blocks of anything. But just these stowage bags? And the stuff inside them? Like we talked about the water and anything that has any hydrogen in it – they are our primary things to use. We’ve taken a look at the things we will be stowing already and believe that we can provide the crew with a safe haven.”
SpaceFlight Insider: There appears to be some confusion about the type of heat shield that the first Orion spacecraft will use for the Exploration Flight Test 1 mission later this year. Is it the same as the main line Orion which will be used to carry crews into deep space?
Geyer: “So, the heat shield and the structure underneath the heat shield, which is the other key piece – because the structure under the heat shield has to not only hold the heat shield – but it also has to protect the crew on landing…So, underneath there is this composite skin with this titanium skeleton.
That is going to be exactly the same as on EM-1 (Exploration Mission 1 – the first flight of Orion on the Space Launch System heavy-lift booster) except for, we’ve found some areas which we’ve milled it, we’ve lightened it and taken some layers off, take a few of the ribs out. We’ve made some of the ‘skeleton’ skinnier and in so doing saving a few hundred pounds. It’s basically the same, we’re essentially optimizing it.
The AVCOAT is still the AVCOAT on EM-1 – in some areas it might need to be a little thicker, we’re still studying that – but it’s basically the same design.
Because cost is a big deal, we’re looking at a way to potentially transition to an AVCOAT block architecture, where you basically makes squares, blocks of this stuff and then you use an epoxy to hold them together. There’s a way to do that which allows us to relieve some of the stresses that we’ve been seeing and it might also reduce our fixed cost because we can build those blocks over time as opposed to a really big build-up.
We’re supposed to make a decision in early October as to which way we’re going in regards to the heat shield. Both of these systems are still AVCOAT it’s just a subtle technique about how we build up the AVCOAT. That’s a great example of why flying EFT-1 will be so important. As we were building the heat shield for use on that mission we thought we had a system exactly as it was designed. We found some issues with material properties, which is how we found some cracks in it. The heat shield is a big thing and through testing and its manufacture we are learning some key things about how the material behaves and we are going to tweak that on EM-1.”
SpaceFlight Insider: Can you talk about Orion’s up mass capabilities?
Geyer: “Mass is a precious commodity in terms of any space mission. If you took a pound of mass and you stick it in LEO and then you try and accelerate that mass around the Moon and then decelerate it to the surface – you’re going to multiply each of those pounds by nine – and that’s to produce the infrastructure needed to support the acceleration and deceleration of that one pound mass. That multiplier of nine turns into things like Service Module propellant, Command Module propellant, other prop systems and the engines and the tanks and all of that kind of stuff.
Mass is everything in terms of space flight and we looked at a number of ways in which to lighten the spacecraft. About 40 percent of Orion is made up of composite materials. We also have titanium, aluminum-lithium for the primary structure. Structures that are light, but they are fairly complex to machine. We made these choices so as to achieve mass efficiency.
We do a lot of drop-testing so as to understand the loading which drives the size of the structure, those kind of things. So, that’s what drives you to get down to the minimum mass.
In the case of contingencies, if you are in LEO, you can get down to the ground, or in the water fairly quickly, say about 45 minutes to an hour. You also can have systems which supply air into the cabin as fast as you were losing it, if there was a leak to feed the leak as it were – that’s easy to do when you’re in LEO.
When you’re at the Moon or one of these cislunar missions where you could be seven days away – you can’t do that. So, it drives you to do things like support the crew in their suits for several days. So, Orion is built to handle a totally depressed (depressurized) cabin, with the suits tied to the ECLSS (Environmental Control and Life Support System) system for 144 hours roughly and we can get the crew home. That is the kind of thing that you have to do when you’re a long way from home to protect the crews. Things that you wouldn’t have to do in LEO and that adds complexity and it adds cost and a lot of design iteration to get that right.
SpaceFlight Insider: Are the communications systems different on Orion as opposed to if it were designed for just LEO operations?
Geyer: “Yeah, absolutely. One of the things is when you go beyond LEO – you’re no longer using TDRS (NASA’s Tracking and Data Relay Satellites) – you’re using the Deep Space Network. There are differences that requires us to synch up with DSN in the way that we transmit data, so that’s a difference, one which limits some of your other capabilities. When you get past LEO – you’re no longer talking to TDRS – you got to it through the DSN.”
SpaceFlight Insider: Is Orion is designed from a crew of 6 or 7? Either way, all the supplies that the crew would need has to travel with them which means that they would need to transport all of that with them, a further consideration in terms of a BEO missions. Is this a correct assessment?
Geyer: “To me the volume is a big part of Orion and its flexibility to be able to do a lot of different missions. We can max the system out with four crew members flying a 21-day mission. That’s four people with their suits, food, all that kind of stuff and some minimal exercise that they could do for 21 days – that basically decides the volume that you see.
Now you can use that in a lot of different ways. You could send two people for longer or six people for shorter. I don’t know where you heard seven…but we have a design where we can take six people. I know that on Skylab, there was some heroic ways to bring more people home, but, fundamentally, we have a main line design that can handle six people.
If we flew six people, that means that we can’t do 21 days, it would have to be a shorter mission. This type of design provides a great deal of flexibility. On a lot of these proposed Mars missions you have six person crews that is actually on the surface. So Orion would be perfect for launching them up to this Mars Transfer System and then letting them enter directly back to the surface on their return to Earth.
SpaceFlight Insider: Is NASA considering a four person crew for the Asteroid Retrieval Mission?
Geyer: “One of the first missions that we are looking at is ARM – where we think we can do with just two people – which would give us greater flexibility…”
SpaceFlight Insider: Is NASA considering a two person mission?
Geyer: “I am designing Orion for four persons for 21 days. So that a driver in terms of the design. The particular ARM design reference mission that people are talking about – right now we would only need two people. However, we use the volume for there supplies and bringing stuff home.”
SpaceFlight Insider: Mark, again, thank you for taking the time to tell our readers a bit about your efforts.
Geyer: “Sure, no problem!”
As noted, Orion’s first flight, EFT-1, is slated to take place in December of this year. EFT-1 will travel some 3,600 miles above the Earth before reentering the Earth’s atmosphere at speeds reaching about 20,000 miles per hour. This will be one of the first steps under NASA’s directive to return to the business of crewed exploration of the solar system.
The competitors under CCP are set to learn which of them will be tapped to move on to the next phase of the program, the Commercial Crew transportation Capability or “CCtCap” within the coming days or weeks. The participants under this initiative include the following:
Dragon, SpaceX: Space Exploration Technologies Corporation, or better known as SpaceX, is a space transport services company based out of Hawthorne, California. Founder and CEO of SpaceX, Elon Musk, created the company with the goal of reducing space transportation costs and enabling colonization of Mars. In 2006, NASA awarded SpaceX a part of the Commercial Orbital Transportation Services (COTS) contract to design and demonstrate a launch system to send supplies to the International Space Station. On May 25, 2012, SpaceX became the first private company to send a spacecraft to the orbiting laboratory. The spacecraft, known as Dragon, is sent to orbit atop the Falcon 9 launch vehicle (also produced by SpaceX) to transport cargo and possibly crews to the ISS.
- Upmass capability of 13,228 lbs. (6000 kg)
- Total return payload mass of 6,614 lbs. (3000 kg)
- Orbit duration of 2 years
- Height of 23.6 ft. (7.2 meters) with trunk
- Cargo racks of honeycomb carbon-aluminum construction designed for zero g environment
- Cargo accommodated in two sections
o Pressurized Section: designed to carry cargo (and possibly astronauts) to orbit; the capsule employs draco thrusters, guidance navigation and control bay (GNC), and advanced heat shield
o Trunk: supports spacecraft during ascent into space, carries unpressurized cargo and solar arrays
- Currently the only cargo spacecraft in service that is capable of returning significant amounts of cargo to Earth
- Part of NASA’s Commercial Crew Integrated Capability phase of NASA’s Commercial Crew Program
SpaceX has been a key partner in NASA’s efforts to transport humans to the ISS as the space agency focuses on missions beyond-Earth-orbit. A crewed mission is expected to take flight in 2015.
Dream Chaser, SNC: Sierra Nevada Corporation (SNC) was founded in 1963 and has a history in developing and providing technology electronics, avionics, and communications systems. Currently, SNC is working on creating Dream Chaser, a commercial crew space transportation vehicle designed to safely transport astronauts to the ISS and other low-Earth orbit destinations. Dream Chaser, built by SNC, is part of NASA’s Commercial Crew Integrated Capability phase of the Commercial Crew Program along with SpaceX and Boeing. Important aspects about Dream Chaser include:
- Reusable lifting-body spacecraft
- Vertical launch off an United Launch Alliance Atlas V 401 rocket
- Horizontal landing on conventional runways and can be handled immediately after
- Crew capability up to 7 crewmembers and cargo
- Low-g reentry (less than 1.5 gs) protects crew and return samples
- Length of 29.5 ft. (9 meters)
- Wingspan of 22.9 ft. (7 meters)
- Mass of 25,000 lb. (11,300 kg)
- Orbit duration of at least 210 days
The Dream Chaser orbital test vehicle is planned to launch on an initial orbital test flight at Cape Canaveral Air Force Station’s Space Launch Complex 41 on November 1, 2016.
CST-100, Boeing: The Boeing Company, commonly referred to as “Boeing,” is working toward creating its own vehicle for commercial space travel. Boeing is currently in the production stage of their Crew Space Transportation -100 (CST-100) capsule. The capsule will transport astronauts to the ISS and other low-Earth orbit destinations like the planned Bigelow Commercial Space Station. The Boeing CST-100 will offer the following features:
- Compatible with multiple launch vehicles (Atlas V, Delta IV, and Falcon 9)
- Initial launch off an ULA Atlas-V 401 rocket
- Crew capability up to 7 passengers and cargo
- Docking up in orbit up to 6 months
- Launch mass of up to 10 tons
- A pressurized vessel that can be reused up to 10 times
- System for landing on land
- Tablet technology to replace manuals
- Wireless internet to assist with communication, entertainment and docking to ISS
In October 2011 NASA announced that Boeing would lease NASA’s Orbiter Processing Facility-3 (OPF-3) at NASA’s Kennedy Space Center to manufacture and test their CST-100 spacecraft. More information on CST-100 can be found on company website here.
Orion Multi-Purpose Crew Vehicle (MPCV), NASA: NASA is building the spacecraft so as to allow the space agency to send crews further out into the solar system than has been attempted prior. The Orion spacecraft will serve as the vehicle for long-duration missions, such as the Asteroid Retrieval Mission and proposed flights to Mars. It will carry crew to orbit, sustain them during their missions, provide emergency abort capability and safe re-entry upon their return. Orion will launch on NASA’s new heavy-lift booster, the Space Launch System (SLS), that is currently under development. Exploration Flight Test 1 (EFT-1) will launch atop a Delta IV Heavy rocket from Cape Canaveral Air Force Station’s Space Launch Complex 37 (SLC -37). Here are some facts on Orion:
- Built by Lockheed Martin for NASA
- Crew capability between 2-6 humans
- Launch off NASA SLS rocket from pad 39B at Kennedy Space Center
- Test launch off ULA Delta IV Heavy rocket (Exploration Flight Test 1 – currently slated for December 2014).
- Ability to stay in space up to 21 days
- Total mass of 46,848 lb. (21,250 kg)
- Habitable volume up to 316 cu ft.
- Pressurized volume up to 691 cu ft.
- Two main components: Crew Module and Service Module
- Crew Module: holds up to 4-6 crewmembers, partial reusability, “auto dock” feature, waste-management facilities, and only part of MPCV that returns to Earth after each mission
- Service Module: primary power and propulsion component that is discarded at the end of each mission (not reusable)
- Expected to take humans on missions to an asteroid and, eventually Mars.
The first mission to integrate Orion and the SLS as a single system, called Exploration Mission-1 (EM-1), is scheduled for 2018. The first crewed mission is expected no earlier than 2021. More information on the Orion Multi-Purpose Crew Vehicle and NASA Exploration Systems Development can be found here.
Portions of this article were written by SFI contributor Talia Landman
Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.