1

National Aeronautics and Space Administration

NASA’s 

Pioneering Next Steps 

in Space Exploration
Introduction

NASA is leading our nation and our world on a journey to Mars. Like the 

Apollo Program, we embark on this journey for all humanity. Unlike Apollo, 

we will be going to stay. This is a historic pioneering endeavor—a journey 

made possible by a sustained effort of science and exploration missions 

beyond low Earth orbit with successively more capable technologies and 

partnerships. 

This pioneering endeavor carries out the direction given to us in the 2010 

NASA Authorization Act and in the U.S. National Space Policy. It engages 

all four NASA Mission Directorates and all NASA Centers and Laboratories. 

It enlists the best of academia and industry across the nation and builds on 

our existing international partnerships while embracing new ones. And like 

pioneering efforts before it, the journey to Mars will foster and attract new 

commercial enterprises. 

Why Mars? Mars is the horizon goal for pioneering space; it is the next tangible 

frontier for expanding human presence. Our robotic science scouts at Mars 

have found valuable resources for sustaining human pioneers, such as water 

ice just below the surface. These scouts have shown that Mars’ geological 

evolution and climate cycles were comparable to Earth’s, and that at one time, 

Mars had conditions suitable for life. What we learn about the Red Planet will 

tell us more about our Earth’s past and future, and may help answer whether 

life exists beyond our home planet. Together with our partners, we will pioneer 

Mars and answer some of humanity’s fundamental questions:

Was Mars home to microbial life? Is it today?

Could it be a safe home for humans one day?

What can it teach us about life elsewhere in the cosmos 

or how life began on Earth?

What can it teach us about Earth’s past, present, and future?

Mars is an achievable goal. We have spent more than four decades on the 

journey to Mars, with wildly successful robotic explorers. The first human 

steps have been taken through science and technology research aboard the 

International Space Station (ISS) and in laboratories here on Earth. We are 

taking the next steps by developing the Space Launch System (SLS) and the 

Orion crewed spacecraft, demonstrating new operations to reduce logistics, 

and preparing for human missions into cislunar space, such as exploring a 

captured asteroid. There are challenges to pioneering Mars, but we know they 

are solvable. We are developing the capabilities necessary to get there, land 

there, and live there. 

1
2

Technology drives exploration and many of the technologies we need are in 

various stages of conceptualization, development, or testing. Consequently, 

NASA will continue to make key decisions and further define steps on this 

journey as technology and knowledge mature. This is a good thing, as it 

allows new ideas, new technologies, and new partnerships to be developed 

during the next two decades of this journey.

This document communicates our strategy and shares our progress. It 

reflects the ongoing discussion with our stakeholders and partners, and 

an update on current plans and activities within an evolving architecture. 

It identifies the challenges facing future pioneers and our strategy for 

addressing these challenges. NASA’s strategy provides an evolutionary, 

resilient framework for defining future missions. We are making progress 

on the journey to Mars using current missions to advance technologies and 

systems for the next decade, and we are conducting the technical analyses 

needed to plan for the decades beyond.

We are on a journey to Mars. We have already taken the first steps. We are 

excited by the challenges that remain, knowing they will only push us further. 

Come join us on the journey!

Contents

Our Goal 3

Our Approach: Pioneering Principles 5

Three Phases on Our Journey to Mars 7

Our Strategy for the Journey to Mars 9

Our Progress and Plans on the Journey to Mars 13

Pioneering Challenges 29

Summary 33
3

Our Goal

NASA aims to extend human presence deeper into the solar system and 

to the surface of Mars. In doing so, our human and robotic explorers will 

expand knowledge and discover the potential for life beyond Earth. Our goal 

is not bound by a single destination. We seek the capacity for people to work, 

learn, operate, and sustainably live safely beyond Earth for extended periods 

of time. We will achieve this goal with a growing number of international 

and commercial partners, realizing economic benefits and strengthening 

America’s leadership on Earth and in space. 

As pioneers, we seek to blaze the trail for others, establishing a presence that 

leads to economic progress and broad societal benefit. We pioneer space to 

discover life, identify resources, foster economic growth, inspire and educate, 

protect ourselves from space-based threats, and leave a better future for the 

next generation. This goal is embodied in the idea of a human and robotic 

journey to Mars. It is time for the next steps, and the agency is actively 

developing the capabilities that will enable humans to thrive beyond Earth 

for extended periods of time, leading to a sustainable presence in deep space.

NASA’s efforts build upon the proven international and commercial 

partnerships at the core of the ISS. Our activities align with the Global 

Exploration Roadmap (GER), a product of 12 space agencies committed 

to expanding human presence in space. We will continue to build on 

partnerships with U.S. industry, academia, and our stakeholders. Our partners 

are developing technologies, systems, and missions to meet individual 

objectives, such as lunar surface operations, while contributing to the journey 

to Mars. The commonality between exploration capabilities, related scientific 

investigations, and the range of potential activities, allows partners to target 

individual objectives while working together to achieve pioneering goals.
4

While far away, Mars is a goal within our reach. We are closer to sending 

humans to Mars than at any point in NASA’s history. We will journey in 

phases, leveraging our experience on the space station to step out into the 

Proving Ground of cislunar space—the volume of space around the moon 

featuring multiple stable staging orbits for future deep space missions. Over 

the next decade, NASA and our partners will use this Proving Ground to 

practice deep-space operations with decreasing reliance on the Earth, gaining 

the experience and systems necessary to make pioneering space and the 

journey to Mars a reality.
5

Our Approach: Pioneering Principles

NASA's approach to pioneering is embodied in a set of guiding principles 

that will increase our successes and benefits over the coming decades. 

These key principles are the basis for a sustainable, affordable space 

program and provide overarching guidance to ensure NASA’s investments 

efficiently and effectively enable the journey to Mars. These principles are:

Strategic Principles for Space Exploration

Implementable in the near term with the buying power 

of current budgets and in the longer term with budgets 

commensurate with economic growth

Exploration enables science and science enables 

exploration, leveraging scientific expertise for human 

exploration of the solar system 

Application of high Technology Readiness Level (TRL) 

technologies for near-term missions, while focusing sustained 

investments on technologies and capabilities to address 

challenges of future missions

Near-term mission opportunities with a defined cadence 

of compelling and integrated human and robotic missions, 

providing for an incremental buildup of capabilities for more 

complex missions over time
Opportunities for U.S. commercial business to further 

enhance the experience and business base

Resilient architecture featuring multi-use, evolvable space 

infrastructure, minimizing unique major developments, with 

each mission leaving something behind to support subsequent 

missions

6

Substantial new international and commercial partnerships, 

leveraging current International Space Station partnerships and 

building new cooperative ventures for exploration

These principles are integrated throughout NASA’s strategy and are 

exemplified in current plans and activities. This document highlights a 

few example applications of these principles, as indicated in relevant 

sections by the icons above.
7

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

Three Phases on 

Our Journey to Mars

EARTH 

RELIANT

The journey to Mars passes through three thresholds, each with increasing challenges 

as humans move farther from Earth. NASA and our partners are managing these 

challenges by developing and demonstrating capabilities in incremental steps.

Earth Reliant exploration is focused on research aboard the ISS. On the space station, 

we are testing technologies and advancing human health and performance research that 

will enable deep-space, long-duration missions.

Human health and behavioral research 

Advanced communications systems

Material flammability tests

Extravehicular operations

Mars mission class environmental control and life support systems

3-D printing

Material handling tests for in-situ resource utilization (ISRU) demonstrations

PROVING 

GROUND

In the Proving Ground, NASA will learn to conduct complex operations in a deep 

space environment that allows crews to return to Earth in a matter of days. Primarily 

operating in cislunar space, NASA will advance and validate capabilities required for 

human exploration of Mars. 

A series of Exploration Missions (EMs), starting with EM-1, the first 

integrated test of SLS and Orion, anticipated in 2018

The Asteroid Redirect Robotic Mission in 2020 that will collect a large boulder 

from a near-Earth asteroid, then ferry it to the Proving Ground and the 

Asteroid Redirect Crew Mission that will allow astronauts to investigate and 

sample the asteroid boulder

An initial deep-space habitation facility for long-duration systems testing

Autonomous operations, including rendezvous and docking and state of the 

art information technology solutions

Concepts to minimize resupply needs through reduction, reuse, and recycling 

of consumables, packaging, and materials

Other key operational capabilities required to become Earth Independent

EARTH 

INDEPENDENT

Earth Independent activities build on what we learn on ISS and in cislunar space 

to enable human missions to the Mars vicinity, including the Martian moons, and 

eventually the Martian surface. With humans on Mars, we will be able to advance 

science and technology in ways only dreamed of with current robotic explorers. Future 

Mars missions will represent a collaborative effort among NASA and its partners—a 

global achievement that marks a transition in humanity’s expansion as we go to Mars 

not just to visit, but to stay.

Living and working within transit and surface habitats that support human life 

for years, with only routine maintenance 

Harvesting Martian resources to create fuel, water, oxygen, and building 

materials

Leveraging advanced communication systems to relay data and results from 

science and exploration excursions with a 20-minute delay
8
9

Our Strategy for the Journey to Mars

The ISS, with flags of the partner nations.

What is Pioneering?

Pioneering space requires a sustained set of mutually 

reinforcing activities—science missions, technology 

development, capability demonstrations, and human 

spaceflight—to expand human presence into deep space 

and extend our robotic agents farther into the solar system, 

with the horizon goal of humans travelling to Mars and 

remaining on the surface. 

NASA’s strategy, aligned with the pioneering 

principles, connects near-term activities and 

capability development to the journey to Mars 

and a future with a sustainable human presence in 

deep space. This strategy strikes a balance between 

progress toward horizon goals, near-term benefits, 

and long-term flexibility to budgetary changes, 

political priorities, new scientific discoveries, 

technological breakthroughs, and evolving 

partnerships. The journey to Mars reflects an 

integrated NASA effort, in collaboration with 

our partners, to advance from today’s Earth 

Reliant human spaceflight program through the 

Proving Ground of cislunar space to an Earth 

Independent, deep-space capability.

This strategy is a natural evolution of prior 

decades of space exploration. The era of 

modern space exploration began with remote 

observations through early telescopes, providing 

the knowledge necessary to design and send 

robotic missions to Earth orbit, planets, moons, 

comets, and asteroids. NASA’s human spaceflight 

program has already demonstrated the capability 

for Earth Reliant human exploration, culminating 

today with the ISS, where astronauts and supplies 

are ferried between the station and Earth within 

hours. Our partners on the ISS, which now 

include commercial spaceflight ventures, reflect 

a blossoming worldwide human spaceflight 

capability for low Earth orbit (LEO). Meanwhile, robotic science missions 

are scouting resources and characterizing potential destinations for human 

explorers at far more distant locations within our solar system. 

The Path Forward

NASA and our partners are already at Mars, operating with highly effective 

robotic emissaries in orbit and on the surface. NASA has exploited nearly 

every opportunity over the past two decades (occurring every 26 months 

when transit between Earth and Mars is the most efficient) to send orbiters, 

landers, and rovers to the Red Planet with increasingly complex experiments 

and sensing systems. Mars orbiters have mapped with high precision the 

topography of the planet, begun mapping the distribution of water ice below 

the surface, imaged geologically ancient river deltas, and discovered likely 

seasonal outflows of salty liquid water in the present. They have mapped 

detailed mineral composition in select areas and located suitable landing 
10

sites for future robotic and human missions, many with incredible science 

potential. Robotic landers have demonstrated that the Martian environment 

could have supported microbial life, as we understand it here on Earth. 

Additionally, robotic landers have measured radiation in transit and on the 

surface, and gathered data for defining entry, descent, and landing (EDL) 

approaches for future human missions. NASA’s Mars 2020 mission will 

measure atmospheric entry conditions and surface dust, and demonstrate 

production of oxygen from atmospheric carbon dioxide while selecting and 

encapsulating samples for potential return to Earth. The journey to Mars 

requires advanced human and robotic partnerships not imagined at the time 

of Apollo.

While learning about Mars with robotic science scouts, we are also developing 

advanced technologies to support human pioneers. NASA is investing in 

technologies and rapidly prototyping new systems, which benefit both NASA 

and our industry partners, while minimizing overall costs through innovative 

partnerships. Focus areas include solar electric propulsion with advanced ion 

thrusters, habitation systems, nuclear fission for Mars surface power, EDL 

systems, laser communications for high data rate transmission, deep-space 

atomic clocks for precise navigation, and many others. NASA will integrate 

these technologies into pioneering capabilities, providing the tools necessary 

for the journey to Mars.

Moving from Earth Reliant toward Earth 

Independent

In the current Earth Reliant phase of human exploration, NASA and our 

partners are using the ISS in LEO, supported by commercial cargo resupply 

services and in the near future, commercial crew transportation. The delivery 

and return of astronauts and cargo to the space station are measured in 

hours, but any journey to Mars will take many months each way, and early 

return is not an option. This is an entirely different operating regime, not 

just for physical access but also for communications with Earth-based teams. 

Astronauts in deep space must be more self-reliant and spacecraft systems and 

operations must be more automated to operate safely and productively as we 

explore beyond LEO. Cislunar space is the ideal Proving Ground for NASA 

and its partners to test systems and to practice deep-space operations, such 

as extravehicular activity (EVAs or spacewalks), and rendezvous and docking 

prior to committing crew on long missions to Mars. NASA is focusing on 

Proving Ground activities in cislunar space, and many of our partners see 

cislunar space as a step toward human missions to the lunar surface. These 

combined activities provide an optimal condition to demonstrate integrated 

human and robotic missions to build confidence that human missions to Mars 

can be safely conducted with an Earth Independent mode of operation. 
Our Strategy for the Journey to Mars

Living and working in space require accepting risk, and the journey is worth the risk. 

Crews must be protected from the unique hazardous environments of deep space 

and on the Martian surface. Often, systems will have to operate autonomously or 

remain dormant for years in preparation for crew. Overcoming these challenges will 

be essential on the journey to Mars. These technological and operational challenges 

fall into three categories: transportation, sending humans and cargo through space 

efficiently, safely, and reliably; working in space, enabling productive operations for crew 

and robotic systems; and staying healthy, developing habitation systems that provide 

safe, healthy, and sustainable human exploration. Bridging these three categories are 

the overarching logistical challenges facing crewed missions lasting up to 1,100 days 

and exploration campaigns that span decades.

11

An Orbital ATK Cygnus 

is berthed to the ISS with 

1.6 tons of supplies during 

the Orb-1 mission in 

January 2014.

Planning and Implementing a Pioneering 

Approach

A pioneering approach enables a sustained expansion of human presence into the 

solar system, rather than a once-in-a-generation expedition. This approach 

requires us to recognize and address two key challenges. 

The first challenge is recognition that pioneering space is as much a logistics and 

supply chain challenge as a technological challenge. Historically, pioneers on Earth 

could not rely solely on supplies from home to sustain them and neither can the 

first pioneers on Mars. NASA will have to learn new ways of operating in space, 

based on self-reliance and increased system reliability; ISRU, including recycling 
packaging materials and trash; and the ability to design, build, or repair 

systems with common, modular components. To enable the journey to Mars, 

NASA will invest in reusable systems with common components that are 

modular and extensible to multiple missions to reduce unique developments 

and the need for spares. Complex tradeoffs between resupply and use of insitu resources must be first addressed before we achieve Earth Independence. 

NASA will use missions in the Proving Ground to validate new operational 

approaches and learn how to balance logistics sent from Earth with the 

potential benefits and challenges of using local resources. 

The second challenge is recognition that achieving Earth Independence 

will take decades and can be impacted by multiple uncertain events. NASA’s 

strategy must be flexible and resilient to changes in the priorities of future 

administrations, the emergence of breakthrough technologies, discovery 

of new scientific knowledge, fluctuations in funding, and new partnership 

opportunities. Due to these uncertainties, we must make decisions with 

incomplete knowledge to ensure continued momentum. However, we 

can plan for these changes proactively and design for uncertainty to be 

better positioned when change occurs. We do this by designing a resilient 

architecture that focuses on critical capabilities across a range of potential 

missions, investing in technologies that provide large returns, and maximizing 

flexibility and adaptability through commonality, modularity, and reusability. 

The journey to Mars is only possible through multi-use, evolvable space 

infrastructure that minimizes unique developments and associated cost. We 

also ensure each mission leaves something behind to reduce the cost, risk, or 

schedule for the next mission. 

12

Features of a Resilient Pioneering Approach

Logistics

Design to minimize the number of systems, use them multiple 

times, refresh instead of replace them, and maintain with local 

resources to enable self-sufficient missions. 

Modularity Standardize for flexibility, simple interfaces to enhance complex 

subsystems and components. 

Commonality Develop systems that serve multiple purposes across the 

campaign at many destinations.

Extensibility Develop initial hardware with paths for enhanced applications.

Affordability Optimize system development across a campaign, not a mission 

to minimize development costs.
13

Our Progress and Plans on the 

Journey to Mars

SpaceX’s uncrewed 

Dragon cargo spacecraft 

is berthed to the ISS after 

arriving on September 23, 

2014 with 2.5 tons of 

supplies and equipment.

NASA’s current efforts focus on strategic investments to extend human 

access to deep space, learn how to operate with reduced logistics, and 

understand future destinations through science-guided robotic explorers. We 

will use the Proving Ground to demonstrate capabilities that evolve beyond 

the Earth Reliant exploration systems currently used on the ISS. As these 

capabilities are proven, NASA and our partners will further define future 

missions. Efforts made today and in the next decade will lay the foundation 

for an Earth Independent, sustained presence in deep space, addressing a 

challenge worthy of our nation’s expertise, perseverance, and ingenuity.

The following sections describe specific architecture elements in each 

phase of the journey to Mars: Earth Reliant, Proving Ground, and Earth 

Independent. These investments, selected with guidance from strategic 

partners and through the lens of the pioneering principles, enable near-term 

missions, support resilient space infrastructure, are affordable within NASA’s 

current budget, and offer multiple opportunities for academic, commercial, 

and international partnerships. They work together as an interlocking set of 

capabilities that enable sustainable, affordable, programmatically sound, and 

technically feasible architecture. Additional detail is provided for the first 

series of exploration missions, including initial SLS and Orion missions and 

the Asteroid Redirect Mission. For missions beyond the next decade, insight 

from ongoing studies is provided. 
14

Earth Reliant

NASA’s current human exploration activities occur 

in an Earth Reliant frame of operations on the ISS. 

To begin to break these ties, NASA is leveraging 

the space station as a test bed to demonstrate key 

exploration capabilities and operations. Current NASA 

missions are building on the Earth Reliant capabilities 

to enable missions for the next decade. The agency 

is also facilitating a robust commercial crew and 

cargo transportation capability in LEO, stimulating 

new markets and fostering an emerging commercial 

space industry that will mature to support future 

pioneering missions. As NASA transitions beyond 

LEO and continues to pioneer space, our vision is that 

private and public investments will sustain economic 

activity in LEO and create benefits for Earth through 

commercial supply and public and private demand. 

The First Steps:

International Space Station (ISS)

NASA has begun the transition from exploration to 

pioneering on the ISS. Occupied by an international crew 

continuously since November 2, 2000, the station has 

hosted more than 200 people from 17 countries, and is the 

culmination of one of the largest and most complicated 

international engineering efforts ever attempted.

The ISS is the only microgravity platform for the long-term testing of new 

life support and crew health systems, advanced habitat modules, and other 

technologies needed to decrease reliance on Earth. Over the next decade, 

we will validate many of the capabilities needed to maintain a healthy and 

productive crew in deep space. Currently manifested or planned experiments 

and demonstrations include improved long-duration life support for 

Mars missions, advanced fire safety equipment, next-generation spacesuit 

technologies, high-data-rate communications, techniques to reduce logistics, 

large deployable solar arrays, in-space additive manufacturing, advanced 

exercise and medical equipment, radiation monitoring and shielding, humanrobotic operations, and autonomous crew operations. 

Aboard the ISS, NASA and its partners also conduct targeted research to 

improve our understanding of how humans adapt and function during 

long-duration space travel. Current and planned risk-reducing investigations 

include bone and muscle loss studies, understanding the effects of intracranial 

pressure changes and fluid shifts, monitoring immune function and 

Astronaut Scott 

Kelly and cosmonaut 

Mikhail Kornienko 

have teamed up for 

a one-year mission 

to understand how 

humans adjust to longduration microgravity, 

bringing us one step 

closer to Mars
cardiovascular health, conducting nutritional studies, and validating exercise 

protocols. With these studies, NASA explores the physiology of the human 

body, preparing for long-duration spaceflight and supporting development of 

terrestrial drugs and therapeutic practices. NASA and our partners’ activities 

on the ISS are achieving key milestones and enabling a planned transition to 

early pioneering missions in cislunar space.

Leveraging U.S. Industry: Commercial Crew and Cargo

The guiding principles for pioneering space include leveraging non-NASA 

capabilities and partnering with industry whenever possible. NASA’s 

acquisition strategy for commercial crew and cargo services embodies these 

principles. The ISS plays a key role as a destination and anchor customer 

for emerging commercial markets in LEO. Commercial partners, who are 

maturing their business models and technical approaches by providing critical 

services for the ISS, will be essential to enabling deep-space NASA missions.

The NASA-sponsored Commercial Orbital Transportation Services (COTS) 

program resulted in the development of new launch vehicles and cargo 

spacecraft. Both Space Exploration Technologies (SpaceX) and Orbital ATK 

have successfully delivered cargo to the ISS using vehicles developed with 

NASA support. Under the Commercial Resupply Services (CRS) and followon contracts, commercial partners are expected to provide about six flights 

per year to support ISS operations. These flights are win-win arrangements 

for NASA and industry, as they minimize the need for costly, NASA-unique 

infrastructure and increase commercial access to space. 

In September 2014, NASA announced the next phase of the commercial 

services program, Commercial Crew Transportation Capability (CCtCap), 

under which NASA awarded contracts for crew transportation services to 

Boeing and SpaceX. Once the companies complete development and are 

certified by NASA, the agency will purchase two flights per year to deliver 

and return expedition crew. CCtCap will provide NASA and our international 

partners with additional vehicles to deliver crews to the ISS and expand 

research opportunities by enabling the crew aboard ISS to increase from six 

to seven. NASA also continues relationships with other U.S. companies that 

are developing alternative transportation systems. 

Beyond commercial crew and cargo transportation services, NASA is 

also developing strategies to stimulate sustained economic activity in 

LEO. This includes leveraging the ISS; supporting a policy and regulatory 

environment that promotes commercialization of LEO; facilitating a robust, 

self-sustaining, and cost-effective supply of U.S. commercial services that 

accommodates public and private demands; and stimulating broad sectors of 

the economy discovering benefits of LEO.

15

Our Progress and Plans on the 

Journey to Mars

NASA relies 

on commercial 

services it helped 

develop, leading 

to economically 

efficient exploration
16

NASA is also leveraging industry to reinvent ground operations for a flexible, multiuser spaceport, providing launch services for both government and commercial 

partners. Launch complex assets once used for the space shuttle have been 

modernized for next-generation transportation systems. Many of these assets also 

provide opportunities for the commercial space industry. For example, Boeing's

Crew Space Transportation (CST)-100 Starliner commercial spacecraft is processed 

in the former NASA orbiter processing facility, and SpaceX plans to use Launch 

Complex 39A, a former space shuttle launch pad, for commercial heavy-lift launch 

vehicles. These and other innovative commercial partnerships have reshaped the

way NASA provides launch services through a multi-user spaceport. 

An Orbital ATK Cygnus approaches the ISS during its demonstration flight in September 2013.
17

Our Progress and Plans on the 

Journey to Mars

Over the next 10 years, commercial partners will likely increase their presence 

in LEO by providing more products and services to government and nongovernmental customers. A mature market provides reliable, on-demand, 

low-cost services, freeing NASA resources for more complex missions and 

system development. These commercial service providers help NASA execute 

an ambitious deep-space human exploration strategy within the agency’s 

anticipated budgets. 

The Proving Ground

Starting early next decade, NASA will be part of a larger international 

community of exploration and commercial activity in the Proving Ground—a 

resilient, evolvable effort to extend human presence beyond LEO. NASA 

identified several objectives for Proving Ground missions, which are critical 

steps on the journey to Mars. These objectives range from demonstrating 

Proving Ground Objectives

Category Title Objective

Transportation Crew 

Transportation

Provide ability to transport at least four 

crew to cislunar space. 

Transportation Heavy Launch 

Capability

Provide beyond LEO launch 

capabilities to include crew, comanifested payloads, and large cargo.

Transportation In-Space 

Propulsion

Provide in-space propulsion 

capabilities to send crew and cargo 

on Mars-class mission durations and 

distances.

Transportation

Deep Space 

Navigation and 

Communication

Provide and validate cislunar and Mars 

system navigation and communication.

Working in Space Science Enable science community objectives.

Working in Space Deep Space 

Operations

Provide deep-space operations 

capabilities:

•

•

•

•

•

Extravehicular activity (EVA)

Staging

 Logistics

Human-robotic integration

 Autonomous operations

Working in Space In-Situ Resource 

Utilization

Understand the nature and distribution 

of volatiles and extraction techniques, 

and decide on their potential use in the 

human exploration architecture.

Staying Healthy Deep Space 

Habitation

Provide beyond LEO habitation 

systems sufficient to support at least 

four crew on Mars-class mission 

durations and dormancy.

Staying Healthy Crew Health

Validate crew health, performance,

and mitigation protocols for Marsclass missions.
18

advanced solar electric propulsion (SEP) for interplanetary cargo transportation 

to in-space operations and deep-space habitation. New missions and activities 

will become possible as NASA and its partners validate capabilities, address 

Proving Ground objectives, and review the specific series of near-term 

missions. Through these missions, we are moving toward Earth Independence 

and progressing together on the journey to Mars.

A Robust Transportation Infrastructure: Ground Operations, 

Orion, and SLS

NASA is developing a robust launch services capability, which not only 

supports SLS and Orion, but can also be leveraged by a multitude of new 

commercial launch providers. With commercial partners, the agency is 

modernizing Launch Complex 39B, developing a mobile launcher, upgrading 

control systems, and demonstrating ground processing capabilities to enable 

Proving Ground missions, including the launch of SLS and Orion.

Orion is a launch, reentry, and in-space crew spacecraft designed to transport 

a crew of four to deep space. During Proving Ground missions, Orion will 

protect the crew during transport to cislunar space, sustain the crew for short 

durations while in space, and enable safe reentry. For future missions, Orion 

will provide transportation between Earth and the Mars transit systems located 

in cislunar space. Orion’s first mission, Exploration Flight Test 1 (EFT-1), 

was successfully conducted in 2014, on a Delta IV Heavy launch vehicle, and 

generated a wealth of data to enable future human missions to deep space. 

The Space Launch System is Orion’s ride to deep space. NASA is developing 

an evolvable design for SLS that leverages previous launch system investments. 

The initial “Block 1” SLS is designed to carry Orion, as well as cargo, 

equipment, and science experiments to staging points in cislunar space. We are 

well along the path to developing the Block 1 SLS, which uses an upper stage 

derived from the Delta cryogenic second stage to launch 70 metric tons (mt) to 

orbit. This initial version will use liquid hydrogen and liquid oxygen propulsion 

systems and solid rocket boosters, evolved from heritage systems. NASA plans 

to upgrade the boosters and develop an advanced upper stage, the Exploration 

Upper Stage (EUS), leading to the 105 mt Block 1B and the 130 mt Block 2

versions of the SLS. This payload capacity far exceeds the capability of current 

and planned commercial launch vehicles. Development of Block 1B with the 

EUS provides significant additional capability for Proving Ground missions, 

allowing NASA to send the crewed Orion spacecraft, other flight systems, and 

cargo to lunar orbit in a single launch. Additional developments will improve 

SLS performance and reduce manufacturing costs through additive 

manufacturing and advanced out-of-autoclave composite structures.

The initial Block 1 SLS will support the first deep-space exploration mission, 

Exploration Mission 1 (EM-1), anticipated in 2018. Although uncrewed, 

EM-1 will provide the first integrated test of SLS and Orion, including SLS’s 

SLS is an evolvable 

launch vehicle 

leveraging mature 

technologies
19

Our Progress and Plans on the 

Journey to Mars

Evolution of the Nation’s Next Rocket

launch performance, Orion’s heat shield, and deep-space navigation. NASA 

plans to develop the EUS for early exploration missions to cislunar space. 

The EUS addition could provide SLS with a critical new capability for 

crewed Orion missions by allowing secondary payloads to be co-manifested 

within the EUS-to-Orion launch vehicle adapter. While the exact mass and 

volume available for co-manifested payloads have not yet been determined, 

payloads about the same length, twice the width, and one-third the mass of 

a school bus could be launched to cislunar space with Orion. Co-manifested 

payloads, potentially launched as early as Exploration Mission 2 (EM-2), 

could include pressurized modules that extend the deep-space capabilities 

of the Orion spacecraft and help develop a deep-space habitation capability. 

Independent co-manifested payloads, such as robotic science missions, are 

also possible. 

Orion and SLS (with the EUS) provide the core transportation capabilities 

that support Proving Ground missions and enable the journey to Mars. 

Beyond EM-2, NASA is considering a wide range of activities that not only 

demonstrate the ability to live and work in deep space, but also accomplish a 

suite of Proving Ground objectives and validate key operational capabilities 

required to become Earth Independent. While SLS and Orion flight rates 
20

will ultimately be determined by available funding and 

mission requirements, NASA is working towards 

flying at least one crewed mission per year.

Into the Proving Ground: Solar Electric 

Propulsion and the Asteroid Redirect 

Mission 

Solar electric propulsion (SEP) uses energy from 

the sun to accelerate ionized propellant to very high 

speeds. Compared to chemical propulsion, electric 

propulsion provides very low levels of thrust; 

however, it is incredibly efficient and can provide 

thrust continuously for months or years, allowing 

more mass to be transported with far less propellant. 

These systems are an order of magnitude more 

efficient than chemical propulsion systems, with 

a specific impulse (Isp) from 2,000-3,000 seconds 

compared to 200-500 seconds. SEP systems are 

also very resilient and, if refueled, could provide 

a reusable, in-space transportation infrastructure. 

Adding a SEP capability to Orion and SLS provides a robust transportation 

infrastructure for human missions to support the journey to Mars.

High-power SEP is a key enabler for NASA’s pioneering strategy, allowing 

NASA to pre-position infrastructure and resources while reducing the surge 

of launches. This could reduce the costs estimated in previous human Mars 

mission studies. Pre-positioning supplies months or years ahead of crew, 

rather than aggregating all necessary equipment and supplies in Earth orbit, 

is often called a split mission. With several tons of xenon (Xe) propellant 

and solar arrays capable of generating 40 kilowatts (kW), an early SEP 

vehicle could efficiently position several tons of cargo throughout the solar 

system. A more advanced SEP system with additional power and propellant 

could deliver landers, habitats, and supplies to Mars orbit. 

NASA is considering several mission architectures that evolve from a 40 kW 

SEP vehicle. In an approach that leverages both SEP and chemical propulsion, 

a Mars SEP cargo vehicle would transport chemical return stages, habitats, 

and landers to Mars orbit, while crew travel separately. For this approach, the 

crew would rendezvous with the pre-positioned assets in Mars orbit including 

a surface lander and, on the return trip to Earth, chemical departure stages. In 

an alternative approach, NASA would use a hybrid SEP vehicle, supplemented 

with small chemical engines for strategic high-thrust maneuvers, to reduce trip 

times. This vehicle would still pre-position landers, habitats, and equipment 

in a cargo mode; however, for crew transit, the vehicle would contain enough 

propellant for a round trip and would not require chemical return stages. Both 

approaches are being studied as the Mars transportation architecture evolves.

SEP enables nearterm missions while 

proving capabilities 

for a reusable deep 

space transportation 

system
21

Our Progress and Plans on the 

Journey to Mars

With SEP, NASA can also aggregate, refurbish, and reuse Mars transportation 

infrastructure in a high-energy orbit, such as lunar distant retrograde orbit 

(LDRO). High performance liquid oxygen and hydrogen propulsion from the 

SLS Exploration Upper Stage can provide the majority of departure energy, 

placing payloads in these high-energy orbits and allowing the SEP or SEPhybrid thrusters to initiate the maneuver to Mars. As an added advantage, these 

maneuvers can be reversed, allowing NASA to capture the Mars return vehicle 

for refurbishment and reuse. Developing and demonstrating advanced SEP 

systems early during the Proving Ground missions will accelerate our progress 

toward sustainable pioneering.

The Asteroid Redirect Mission (ARM) provides a near-term opportunity to 

demonstrate several capabilities important for longer-duration, deep-space missions, 

including flight-validated SEP transportation. ARM consists of two challenging 

flight segments, working toward the common objective of human exploration of 

an asteroid. In the first segment, an advanced, high-power SEP robotic vehicle 

will travel to an asteroid, perform detailed reconnaissance of its surface, select a 

boulder-sized sample, capture it, and return to a stable orbit in cislunar space. Most 

robotic sample return concepts are designed to return a few hundred grams of 

material (e.g., NASA’s OSIRIS-REx mission to the asteroid Bennu). All six Apollo 

landings returned a total of less than 400 kilograms. Leveraging SEP and advanced 

robotics, ARM will return several tons of material. In the second segment, 

astronauts will travel to the captured boulder aboard SLS and Orion, marking a 

historic opportunity that will allow humans to venture outside of the spacecraft to 

touch, investigate, and experience an asteroid firsthand.

The Asteroid Redirect Mission also leaves deep-space infrastructure in cislunar 

space, providing an aggregation point to support the journey to Mars. Following 

the first ARM crewed mission, there will be on the order of several tons of 

material remaining in a stable orbit for at least 100 years, available for future 

exploration, scientific, commercial, or academic partners. During potential future 

missions, NASA could use the boulder to demonstrate ISRU identification, 

characterization, extraction, processing, and containment capabilities, and test 

EVA tools for exploring other low-gravity bodies, such as the Martian moons 

Phobos and Deimos. The Asteroid Redirect Robotic Vehicle (ARRV) also 

will be able to provide some support to visiting vehicles, including an S-band 

transponder for approach and docking, an X-band communications link, and 

about 40 kW of power. This initial cislunar infrastructure would be available to 

commercial partners who may also wish to understand and eventually mine 

resources from asteroids. Such commercial efforts could evolve into services to 

support in-space fueling of Mars propulsion systems.

A Home Away from Home: Deep-Space Habitat 

Any mission to Mars will require highly reliable habitation systems to keep the 

crew healthy and productive in the deep-space environment during missions 

that last up to 1,100 days. Leveraging experience from the ISS, NASA and our 
22

international and commercial partners have begun activities to evolve ISS 

habitation systems to meet future deep-space mission needs. With multiple 

crewed Orion missions to cislunar space over the next decade (launched on an 

evolved SLS), NASA will have many opportunities to use these habitations 

systems, and evolve them to a deep-space habitation capability for future Mars 

missions. This approach allows us to validate habitation system performance 

and reliability in the deep-space environment prior to committing a crew on a 

long journey to Mars. 

NASA, together with its international and commercial partners, will develop a 

strategy to complete “Mars-ready” habitation system testing on Earth and on 

ISS. NASA and its partners will also develop an initial habitation capability for 

short-duration missions in cislunar space during the early 2020s and evolve this 

capability for long-duration missions in the later 2020s. A modular, pressurized 

volume would enable extended stays by crews arriving with Orion. This initial 

habitation capability in cislunar space would demonstrate all the capabilities and 

countermeasures necessary to send humans on long-duration transit missions to 

Mars. With this long-duration habitable volume and resources, NASA and its 

partners will have the opportunity to validate Mars habitat concepts and 

systems, including exercise systems, environmental monitoring systems, longduration consumables storage, fire safety in high-oxygen environments, 

radiation shielding, and high-reliability avionics with long periods of dormancy. 

Understanding the transition from dormancy to crew presence and back is 

particularly important and can be tested with this capability. Between crewed 

missions, deep-space habitation capabilities could be used to test autonomous 

mission operations and transfer of control from the ground to vehicle systems 

in preparation for the longer Mars missions. Many of the capabilities developed 

for NASA’s deep space missions will also be useful for other missions—

including potential future commercial low Earth orbit space stations used by 

other government agencies and the private sector as the agency transitions away 

from the Space Station after 2024. 

As designs for the Mars transit vehicle evolve and trajectories are determined, 

future Proving Ground missions could launch additional modules to 

incrementally build up capability. Using standardized interfaces, common 

structures, and modular designs, multiple pressure vessels could be aggregated, 

leading to a more complete habitation system to validate the full suite of 

capabilities needed for the journey to Mars. Commonality and standardization 

reduce unique developments and improve logistical efficiency. Standards also 

increase opportunities for international and commercial partnerships. During the 

habitat build-up and after initial missions, outdated or failing systems could be 

replaced with new capabilities that leverage the standardized interfaces. This 

approach provides an initial cislunar exploration capability with a pathway to a 

reusable, evolvable infrastructure for human missions to Mars.

Standard interfaces 

enable multi-use, 

evolvable systems 

to support transit 

habitats, Mars ascent 

vehicles, and surface 

mobility 
23

Our Progress and Plans on the 

Journey to Mars

Becoming Earth Independent

Part of the journey to Mars is increasing our knowledge base and assessing 

plans and architectures that are affordable and sustainable. When the first 

pioneers ventured to North America, they found familiar resources in the new 

land and adapted to their environment. Future pioneers of Mars will have to 

adapt to a more foreign, hostile environment. We will need new technologies to 

transform local resources into water, fuel, air, and building materials. Therefore, 

in parallel with planning and implementing Proving Ground missions, NASA 

is leveraging current and planned robotic missions and studies to better 

understand challenges and opportunities that will inform the design of future 

systems. Earth Independent capabilities include those validated in the Proving 

Ground, Mars surface landers, advanced and efficient ISRU, surface mobility, 

permanent surface habitats, and crew transfer vehicles, such as the Mars ascent 

vehicle or a Mars vicinity crew taxi. These capabilities enable an integrated and 

sustainable campaign to pioneer space. 

On the Red Planet: Robotic Mars Missions

We are already in orbit around and on the surface of Mars with a fleet of 

robotic science explorers. Robotic pathfinders like Curiosity address both 

science and human exploration objectives, answering key questions and 

gathering knowledge necessary to prepare human pioneers. NASA has 

significant experience using robotic science and exploration pathfinders, 

such as the Lunar Reconnaissance Orbiter (LRO) mission to the moon, the 

Dawn mission to asteroids Vesta and Ceres, and the Mars Exploration Rovers 

Spirit and Opportunity. Along with conducting their high-priority science 

objectives, robotic pathfinders investigate and map destinations prior to human 

missions, collect surface samples, characterize potential landing sites, and test 

technologies necessary for future robotic and human destination systems. Over 

the next decade, NASA will rely on robotic pathfinders to help select humanaccessible landing sites, pre-emplace infrastructure, and inform the design of 

human destination systems. 

NASA is currently working on several new robotic missions to conduct 

transformational science and support future human surface missions. Some 

missions, such as the Origins Spectral Interpretation Resource Identification and 

Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission, will 

acquire data on potential near-term destinations in collaboration with international 

exploration efforts. Additionally, proposed lunar robotic missions could verify 

the accessibility of resources to enable the journey to Mars. For Mars, NASA 

is currently developing the Interior Exploration using Seismic Investigations, 

Geodesy, and Heat Transport (InSight) mission, set for launch in 2016, as well 

as the Mars 2020 rover mission. NASA also is supporting the European Space 

Agency’s ExoMars orbiter and lander, by testing precision navigation technology 

and looking for evidence of the chemical building blocks for life. 

Current and 

planned science 

missions address 

pioneering 

challenges
24

InSight informs human exploration in addition to its primary science 

objectives. InSight is a robotic lander that will investigate the interior 

(geophysical) processes that formed Mars’s core, mantle, and crust, comparing 

these processes to the Earth. InSight also will investigate seismic activity and 

meteorite impact rates on Mars that may affect the design of permanent 

human destination infrastructure.

The Mars 2020 rover is a prime example of the coordination and overlap 

between science and exploration objectives. Mars 2020 will broaden the search 

for signs of past life on the Martian surface, investigate signs of habitable 

environments, and collect samples for a potential future sample return mission 

to Earth. The mission also will provide opportunities to gather knowledge 

and demonstrate technologies that address the challenges of future human 

expeditions to Mars, including EDL. The Mars 2020 rover will carry an ISRU 

payload to demonstrate a method of generating oxygen from the Martian 

atmosphere, which can be used to produce rocket propellant. Landing site 
25

Our Progress and Plans on the 

Journey to Mars

selection for Mars 2020 is not finalized; however, one consideration is the site’s 

potential suitability for future human surface missions. If Mars 2020 lands at 

a potential human landing site, it may help characterize the region for available 

resources, significantly increasing our ability to prepare future pioneers for the 

journey to Mars.

Robotic science pathfinder missions will continue well into the next decade to 

meet high-priority science objectives and prepare for future human missions 

to Mars. Robotic missions after Mars 2020 are in their conceptual stages and 

will address key exploration questions, such as characterizing the complex 

gravitational environment of the Martian moons; identifying resources and 

areas of scientific interest; understanding the effects of space radiation; 

validating EDL techniques; and studying regolith mechanics and dust. 

An Evolving Architecture: Driving Near-Term Decisions 

and Long-Term Robustness 

Like previous pioneers, NASA is charting new territory and we will 

adapt to new scientific discoveries and new opportunities. For example, 

science discoveries in just the past few years have completely changed our 

understanding of water on the moon and the habitability of Mars, enabling 

new architectures that rely on ISRU to reduce logistical burden. Our current 

efforts are focused on pieces of the architecture that we know are needed. In 

parallel, we continue to refine an evolving architecture for the capabilities that 

require further investigation. These efforts will define the next two decades 

on the journey to Mars.

Through rigorous and systematic studies, NASA and our international and 

industry partners have identified the core exploration capabilities necessary 

for Earth Independence. These studies build on a long history of designing 

deep-space missions, allowing NASA to adequately anticipate the challenges 

that future astronauts will face. NASA is leveraging prior experience to 

integrate these capabilities and design an open, evolvable architecture that 

allows us to confidently make investments without making specific decisions 

about missions in the distant future. This approach avoids the trap of 

designing a rigid architecture that becomes obsolete due to unanticipated 

changes. NASA’s strategy, with its focus on capabilities, strikes a balance 

among progress toward horizon goals, near-term benefits, and the flexibility 

to respond to technology advancement, new scientific understanding, 

dynamic partnerships, and political direction in the coming decades.

Early architecture studies provided key findings and critical decision 

points, which help scope future work. Some of these findings, such as the 

commonality of key capabilities across multiple missions, are core to NASA’s 

strategy, while other findings inform specific missions and architectures. 

For example, trajectory analysis has shown LDRO and some other lunar 
26

orbits are viable testing and staging locations, requiring only a small velocity 

change to efficiently transfer systems between a departure orbit and lunar 

orbits. When combined with new operations and system refurbishment, this 

finding supports architectures in which Mars transit systems can be reused, 

reducing overall costs and improving sustainability. Other architecture studies 

have shown that 20-30 mt Mars landers transported by SEP systems may be 

sufficient to enable human Mars missions with the addition of ISRU oxygen 

production for ascent propellant to leave the Martian surface. 

These efforts are allowing NASA and its partners to develop an affordable, 

sustainable, and flexible pioneering architecture. Work to date has helped 

confirm NASA’s approach and demonstrated that there is a viable path that 

can be executed within anticipated constraints. Leveraging the findings of 

current and future studies and precursor missions, NASA is poised to lead 

the worldwide partnership supporting an affordable journey to Mars.

Selected Critical Time Frames and Decisions

DECISIONS MADE & 

IMPLEMENTATION UNDERWAY

Extend ISS operations to at least

2024 

Pursue an evolvable SLS via 

Exploration Upper Stage before 

advanced solid rocket boosters

Select an ARM baseline mission 

to return an asteroidal boulder to 

lunar orbit for subsequent crew 

rendezvous

Predeploy cargo and 

infrastructure through split 

missions

DECISIONS FOR THE NEXT 

FEW YEARS, IN WORK NOW 

Develop an exploration EVA suit 

for use on Orion missions

Define initial deep-space 

habitation capability

Select in-space transportation 

systems

Identify future Mars robotic 

precursor missions beyond Mars 

2020

Further define potential future 

exploration missions in cislunar 

space 

DECISIONS UNDER STUDY 

NOW TO BE MADE IN THE 

NEXT DECADE

Select initial human missions 

beyond the Proving Ground

Identify the role of ISRU in the 

overall logistics strategy

Design Mars surface habitats

Develop Mars surface power 

generation 
27

Our Progress and Plans on the 

Journey to Mars
28
29

Pioneering Challenges

NASA has identified specific scientific and technical challenges for the 

journey to Mars through rigorous studies, including an ongoing series of 

architectural trade analyses, external reviews, assessments of deep-space 

habitation options with international partners, and high-priority objectives 

of science decadal studies. NASA and our partners around the world have 

already solved some of these challenges. The remaining challenges will 

be systematically addressed over the next two decades by the capabilities 

demonstrated through science missions, on the ISS, and in the Proving 

Ground as we move toward Earth Independence. 

The Boeing CST-100

Starliner crewed vehicle, to 

be used for LEO 

destinations. (Boeing)

Transportation

Transportation capabilities are necessary to send humans to space 

affordably and reliably, provide high-thrust access to staging 

points in cislunar space, and efficiently and safely transport crew 

and exploration systems on the longer journey to Mars.

Commercial Cargo and Crew: Advances in transportation 

capabilities are only possible if NASA can shift to a more efficient 

mode of operations for current Earth-to-LEO transportation. 

NASA is partnering with commercial industry to make this shift

possible. Through a commercial crew and cargo capability, NASA can rely on 

a less expensive, flexible commercial market to provide LEO transportation 

services, freeing up resources for beyond LEO and planetary transportation.

Beyond Low Earth Orbit Propulsion—SLS and Orion: A human-class

Mars mission will require unprecedented amounts of mass transported

farther than any previous human mission to space. A single Mars mission

may require several 20-30 mt payloads delivered to the surface to support

the crew as well as an in-space habitat, transportation stages, and supplies for

round-trip missions of up to 1,100-days. In addition to mass, payload volume 

is a challenge. To enable cargo missions, NASA envisions a new 10-meter 

diameter fairing for the evolved SLS to accommodate unprecedented 

volumes. Commercial cargo services may be used to supplement the SLS's 

core role.

In-Space Power and Propulsion: Power is critical for exploration systems; 

however, it is particularly important for the transportation architecture. Each 

human Mars mission will require several cargo launches to pre-emplace

infrastructure and supplies. NASA expects to use high-powered SEP systems

(150- 200 kW) that can transport cargo in a sustainable cadence. SEP requires

50 percent less propellant than chemical propulsion and uses fewer heavy-lift

launches. While SEP takes longer than chemical propulsion to deliver cargo, 

it gives campaign planners more timeline flexibility by providing trajectory

options that are less coupled to the 26-month planetary alignment that drives

traditional chemical propulsion architectures.

NASA’s commercial 

crew and cargo 

program has 

bolstered U.S. 

launch market 

share globally
Entry, Descent, and Landing: EDL is one of our biggest challenges. The 

revolutionary sky crane landing system used for the Curiosity rover placed just 

under 1 mt of payload on the surface of Mars. The smallest viable humanscale lander concept is more than an order of magnitude larger, and it may 

be necessary to land multiple 20-30 mt payloads at a human landing site. 

Consequently, a completely new approach is needed for human-scale EDL. 

For instance, supersonic retropropulsion may be necessary to provide safe 

and accurate atmospheric entry, descent, and precision landing on Mars. 

Ascent from Planetary Surfaces: A Mars Ascent Vehicle (MAV) is required 

to transport crews from the surface to Mars orbit. The MAV drives lander and 

EDL requirements, which in turn impact in-space propulsion and the total mass 

launched from Earth, a major driver for mission cost. Current MAV designs 

require a minimum lander size of just under 20 mt, assuming propellant can 

be generated from the Martian atmosphere via ISRU. The MAV is also critical 

to crew survival, requiring additional reliability and redundancy, zero boil-off 

cryogenic storage, and limited maintenance during years of dormancy. Current 

studies continue to refine our understanding of this critical element.

Communication and Navigation: Currently, Mars robotic rovers have 

data rates around two million bits per second, using a relay, such as the Mars 

Reconnaissance Orbiter. The ISS data rate is 300 million bits per second, two 

orders of magnitude faster. Future human Mars missions may need up to a 

billion bits per second at 1,000 times greater range than ISS, requiring laser 

communications to reduce weight and power. In addition, disruption and 

error-tolerant interplanetary networking and improved navigation capabilities 

are required to ensure accurate trajectories and precision landing. 

Working in Space

Even with 50 years of human operations in space, new capabilities are 

necessary to sustain productive operations for crew and robotic systems

at multiple destinations within the cislunar and Martian environments.

Exploration Extravehicular Activity: New EVA systems must supply 

basic biological needs during spacewalks, provide protection from hostile 

environments, and enable comfort, flexibility, and dexterity to support 

human exploration and investigation of new worlds. These EVA 

systems will be integrated and tested with vehicle interfaces, such as 

suitports, using lower-pressure, higher-oxygen atmospheres (e.g., 8.2 

pounds per square inch with 34 percent oxygen) for rapid and frequent 

EVAs with minimum loss of valuable atmospheric gasses. The 

Asteroid Redirect Crew Mission will be an early opportunity in the 

Proving Ground to validate new EVA systems when crews conduct 

spacewalks to collect samples of an asteroid boulder. The potential 

effects on human health resulting from surface dust and its safe removal 

will also need to be thoroughly understood.

30
31

Human-Robotic and Autonomous Mission Operations: Key features of 

sustainable pioneering are pre-emplacing equipment, reusing infrastructure, 

and relying on robotic capabilities to support humans. Robotic systems can 

help deploy systems, provide assembly, and support maintenance both when 

crew are present and during periods of dormancy. Robotic systems designed 

to work with the crew increase productivity, support EVAs, and are critical to 

crew safety. 

In-Situ Resource Utilization and Surface Power: NASA’s science 

missions have long been searching for water beyond Earth, and they found 

it: everywhere. Sustainable pioneering must leverage water and other 

valuable in-space resources to break the logistical chain from Earth. ISRU 

technology enables the use of local resources, such as water in the form of 

ice crystals or hydrated minerals on the surface of Mars and carbon dioxide 

in its atmosphere, to be used as the feedstock for propellant, radiation 

shielding, and consumables for life support systems. Producing liquid oxygen 

propellant provides a significant architectural advantage—more than half 

of a 35 mt MAV mass is due to propellant, which could be produced locally. 

However, ISRU production for pioneering missions will require significant 

power to convert resources in an acceptable timeframe. ISRU systems will 

leverage high-power generation systems, such as solar or fission power, to 

produce ascent propellant. 

Surface Habitat and Mobility: The most important challenge for human 

pioneering missions is keeping the crew safe for long-duration missions up 

to 1,100 days. Habitats and associated systems and supplies, including food, 

clothing, atmospheric gases, and human interfaces, represent a significant 

portion of any exploration architecture. Habitation includes both in-space 

transit and Mars surface capabilities. NASA can reduce development costs, 

increase reliability, and ensure crew safety over a series of missions by reusing 

and maximizing commonality between the surface, transit, and Mars moons 

habitats and subsystems.

Astronaut Karen Nyberg 

conducts an eye exam on 

herself on the ISS. 

Staying Healthy

Deep-space crewed missions will not have regular access to the Earth’s resources 

or the ability to rapidly return to Earth if a system fails. As crewed missions 

extend farther from Earth for longer periods, the habitation systems must 

become more reliable for safe, healthy, and sustainable human exploration. 

Environmental Control and Life Support Systems (ECLSS): Leveraging 

the ISS, NASA is focused on demonstrating advanced capabilities for robust 

and reliable ECLSS, which must operate for up to 1,100 days with minimal 

spares and consumables. Systems demonstrated on the ISS and Orion will be 

further validated in the Proving Ground environment and incorporated into 

a reliable long-duration, deep-space habitation capability.

Pioneering Challenges
32

Crew Health: Long-duration human missions, including missions with up 

to 1,100 days in microgravity, potentially increase the risks of bone loss, 

atrophy, trauma, neurovestibular issues, loss of clear vision, and illness for 

the crew. To address these increased risks, crews will require new diagnostic, 

monitoring, and treatment tools and techniques, including exercise systems 

and other countermeasures, to maintain crew health. The ISS provides an 

ideal test bed to develop these capabilities. 

Radiation Safety: Outside the Earth’s magnetic field, crew and electronics are 

exposed to high-energy particles, including infrequent, but potentially deadly, 

solar particle events and constant exposure to galactic cosmic rays. These 

high-energy particles can reduce immune response, increase cancer risk, and 

interfere with electronics. NASA’s Human Research Program is developing 

methods and technologies to protect, mitigate, and treat the effects of radiation 

on the crew and their exploration systems. 

The journey to Mars will be further defined through Proving Ground missions 

in the next decade, as NASA and our partners retire these challenges and build 

on the capabilities for sustainable pioneering. We know these challenges are 

solvable and have a strategy in place for maturing the capabilities to address 

them as we expand human presence into deep space.

Cosmonaut Gennady Padalka performs an ultrasound exam on astronaut Mike Fincke 

aboard the ISS during Expedition 9.
33

Summary

We are on a journey to Mars. In the next few decades, NASA will take steps 

toward establishing a sustainable human presence beyond Earth, not just to 

visit but to stay. NASA’s near-term activities focus on increasing our capacity 

to operate, work, and live in space while characterizing future destinations 

with the help of robotic science missions. Pioneering space begins with 

the ISS to ensure we have the reliable, long-duration systems necessary 

for human missions to Mars. In the Proving Ground, we will validate 

key capabilities through EM-1 and EM-2 along with ARM, SEP, cislunar 

habitation, and long-duration testing and operations. These and subsequent 

missions will target challenges and strategic knowledge gaps while helping 

develop the core capabilities necessary to expand human activity farther into 

deep space. 

Pioneering space will require a flexible, integrated, and sustained effort to 

develop the capabilities and tools necessary to support humans throughout 

our solar system. Future missions will face increasingly difficult challenges 

associated with transportation, working in space, and staying healthy. Many of 

these challenges are solved or are currently being addressed on the ISS. For 

the rest, NASA and our partners will leverage the Proving Ground with 

science missions and capability demonstrations to close the remaining gaps 

and ensure we have the ability to get to Mars, land safely, live and work 

productively, and return.
34

NASA’s strategy for pioneering space provides guidance for selecting 

and designing missions in the Proving Ground and enables future 

accomplishments on the journey to Mars. The strategy helps NASA logically 

progress from current Earth Reliant operations on the ISS, through the 

Proving Ground in cislunar space, to Earth Independent pioneering with 

the goal of humans living and working on Mars. This strategy provides the 

flexibility to respond to new discoveries, opportunities, and shifts in national 

priorities. NASA approaches pioneering space as a collaborative effort, 

within the United States and with our international partners, incorporating 

key capabilities from industry and academia, while engaging the public and 

stakeholder communities. The core capabilities NASA is working on with our 

partners—SEP, Mars-ready ECLSS, ISRU, and many more—will enable the 

journey to Mars. 

NASA’s human exploration, science, and technology endeavors are 

intertwined. As our exploration activities reach farther into the solar system, 

we will also broaden our reach here on Earth, enabling more participation, 

partners, activity, and economic and technological benefits. NASA’s current 

investments in exploration capabilities and the decisions being made today 

are crucial to achieving our common goal: extending human presence into 

the solar system and to the surface of Mars.
October 2015

National Aeronautics and Space Administration

NASA Headquarters

300 E Street Southwest

Washington, DC 20546

www.nasa.gov

NP-2015-08-2018-HQ