The Orion multi-purpose crew vehicle is designed to take humans to Mars, but with less than 20 cubic meters of pressurized volume for a crew of four it could get more than a little cozy en route. Commercial cargo vehicles designed to supply the International Space Station (ISS) may add some elbow-room for the long haul to the Red Planet.

Boeing, Lockheed Martin and Orbital ATK all have won small NASA contracts to study how their commercial cargo vehicles could be modified as habitats for Orion crews in the exploration “proving ground” near the Moon. Bigelow Aerospace, which has orbited two “expandable” habitat testbeds, and is scheduled to berth another one at the ISS this fall, is also running a study, and three other companies are studying advanced environmental control and life-support systems (Eclss) for future habs.

As part of NASA’s Next Space Technologies for Exploration Partnerships (NextSTEP) project, the companies are matching space-agency funds with their own resources in 50‑50 cost-sharing arrangements to make work they are doing on NASA’s current needs “extensible” to exploration beyond the ISS and low Earth orbit.

“What we’re trying to do is maximize commercial applications of these technologies while getting an impact for our requirements as well,” says Jason Crusan, director of advanced exploration systems in the Human Exploration and Operations (HEO) directorate at NASA headquarters. “There may be commercial applications for habitation in low Earth orbit at some point. We’d like to understand what industry thinks about that. At the same time we have real requirements for habitation in deep space, and there have been some commonalities in that.”

To meet NASA’s stated goal of exploring Mars with humans in the 2030s, planners envision spending the decade of the 2020s exploring cislunar space, “evolving” the systems it would take for astronauts to operate there for a few months into the spacecraft that would enable 1,000-day missions to the planet and perhaps its moons.

The planned Asteroid Redirect Mission (ARM) to move a boulder from the surface of a near-Earth asteroid into a stable distant retrograde orbit (DRO) at the Moon would not require a separate habitat. An early crew would live in their Orion for three weeks while studying the sample in DRO. Instead, NASA foresees using DRO or one of the Earth-Moon Lagrangian points as a place to practice human operations for as long as 60 days, and to push development of the hardware that would be needed for Mars.

“We’re looking at a modular approach where you have commonality of the elements to minimize the number of unique new elements that need to be built,” Crusan told the NASA Advisory Council (NAC) on April 8. “If you actually do this development up front, we don’t need to develop a surface-specific hab or a transit-specific hab or a taxi-specific hab or an initial short-duration hab.”

Bigelow has based its habitat developments on inflatable-structures work started at NASA’s Johnson Space Center. It has two unmanned habitats in orbit, and in September is scheduled to launch its Bigelow Expandable Activities Module (Beam) to the ISS for testing with humans inside. Boeing, Orbital ATK and Lockheed Martin are competing for second-round Commercial Resupply Services (CRS-2) contracts to support the station, and the latter two are basing the habitat work on their cargo vehicles in keeping with the principle Crusan describes.

Boeing’s CRS-2 proposal essentially pulls the seats, abort engines, Eclss and other human gear from the CST-100 commercial-crew vehicle it is developing for NASA, and replaces it with cargo accommodation. For its NextSTEP habitat study, Boeing is developing a separate vehicle that is intended to be simple and affordable early on, and evolvable for later long-duration missions, according to Crusan’s presentation to the NAC. 

Orbital ATK plans to adapt the Cygnus cargo carrier that already has delivered cargo to the space station under a CRS-1 contract into a habitat for cislunar space that can be expanded by linking its pressurized modules. Lockheed Martin is using the same pressurized module it has proposed for CRS-2 as the basis of a habitat for the NextSTEP study, and is already building a full-scale mockup for the cargo-carrier proposal that also can be used for the habitat study.

Josh Hopkins, the space exploration architect at Lockheed Martin Space Systems, is managing the NextSTEP work internally. In addition to the 40-cubic-meter pressure vessel —built at the same Thales Alenia Space factory in Turin, Italy, that builds the Cygnus—the Lockheed Martin habitat would use the same service module that is the basis of the reusable “Jupiter” space tug the company has proposed for CRS-2.

The habitat version would add an airlock with a second docking port, and a high-gain antenna for communications (see illustration). Life support would be handled by the Eclss in the Orion, with fans to circulate the atmosphere through the capsule, and thermal control systems inside the habitat. Oxygen and some other consumables would be carried in the “exoliner” portion of the Jupiter bus, outside the pressurized section, while drinking water might be used to help shield the crew from space radiation.

Thales Alenia built many of the pressurized modules already attached to the ISS. The proposed Lockheed Martin habitat would be sized to accommodate as many as eight standard station experiment racks that could house advanced Eclss and other developmental exploration hardware, Hopkins says. While Lockheed Martin plans to add electric propulsion (EP) to its Jupiter tug for operations in geostationary orbit, the Jupiter spacecraft is based on the company’s planetary spacecraft and would not need it for cislunar operations.

“We could fly the same propulsion system, the same hardware, that we’re designing for the ISS mission,” Hopkins says. “That was part of the decision process of basing that on an interplanetary bus rather than a low-Earth-orbit bus. The electronics are designed to handle the radiation. It’s designed so it doesn’t need 24-hour-a-day babysitting, and essentially the delta-V is low enough that we can get there with that propulsion system on existing rockets.”

Three other companies won NextSTEP partnerships to conduct advanced Eclss work aimed at extending the range of habitats toward Mars. Dynetics Inc. of Huntsville, Alabama, will study miniature systems to scrub carbon dioxide and other gases from cabin air; Hamilton Sundstrand of Windsor Locks, Connecticut, will work on modular Eclss subsystems designed to use common components, and Orbitec of Madison, Wisconsin, will study “hybrid” systems that merge chemical and biological processes to help close the life-support loop.

While the Lockheed Martin habitat won’t need electric propulsion to reach cislunar space, EP remains a major enabler for prepositioning supplies and habitats at Mars for human explorers. NASA picked three NextSTEP partners to advance their ongoing work in the field—Ad Astra Rocket Co., Webster, Texas, for long-duration tests of its Variable Specific Impulse Magnetoplasma Rocket prototype; Aerojet Rocketdyne, Redmond, Washington, for an operational demonstration of a 250-kw nested Hall thruster, and MSNW, also of Redmond, to advance the 100-Joule Electrodeless Lorentz Force Thruster it has been developing with U.S. Defense Department funds.

Rounding out the NextSTEP partnerships are two 6U‑cubesat resource scouts designed to ride piggyback on the first flight test of the heavy-lift Space Launch System on a swing around the Moon in 2018. Lockheed Martin Space systems will receive $1.4 million for “Skyfire,” which will collect surface spectroscopy and thermography. Morehead State University in Kentucky will get $7.9 million for the “Lunar IceCube,” which will use an infrared spectrometer to seek ice, liquid water and water vapor from a low-perigee, near-polar orbit around the Moon.