NASA Valkyrie
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| NASA Valkyrie (R5) | |
|---|---|
 | |
| General information | |
| Developer | NASA Johnson Space Center |
| Country of origin | United States |
| Year unveiled | 2013 |
| Full name | R5 Valkyrie |
| Named after | Valkyries of Norse mythology |
| Height | 188 cm (6 ft 2 in) |
| Weight | 125 kg (300 lb) |
| Degrees of freedom | 44 |
| Actuators | Series elastic actuators (rotary and linear) |
| Head sensor | Carnegie Robotics MultiSense SL |
| Processors | 2 x Intel Core i7 |
| Battery | 1.8 kWh dual-voltage lithium-ion |
| Operating time | ~1 hour |
| Connectivity | Ethernet, Wi-Fi |
| Cost per unit | ~$2 million |
| Units built | ~6 |
| Status | Active (research platform) |
| Website | nasa.gov/technology/r5 |
NASA Valkyrie, officially designated R5, is a bipedal humanoid robot designed and built by NASA's Johnson Space Center (JSC) in Houston, Texas. Unveiled in December 2013, Valkyrie was originally created to compete in the 2013 DARPA Robotics Challenge (DRC) Trials. The robot stands 188 cm tall, weighs 125 kg, and possesses 44 degrees of freedom powered entirely by electric series elastic actuators. Its name is drawn from Norse mythology, where Valkyries are supernatural figures who choose which warriors may enter Valhalla.
Valkyrie represents NASA's most advanced full-body humanoid robot to date, building upon more than 18 years of humanoid robotics heritage at JSC that includes the Robonaut program. Unlike its predecessor Robonaut 2, which was designed as an upper-body torso for work aboard the International Space Station, Valkyrie is a complete bipedal platform intended to operate in degraded or damaged human-engineered environments, whether on Earth during disaster response or on other planets as a precursor to human exploration missions. The robot features a distinctive glowing LED chest emblem bearing the NASA logo, a design element that drew widespread comparisons to the arc reactor of Marvel's Iron Man [1].
Since its debut, Valkyrie has served as a research platform at multiple institutions worldwide. NASA loaned units to MIT, Northeastern University, and the University of Edinburgh, where the robot spent a full decade advancing research in humanoid locomotion, manipulation, and autonomous perception before returning to JSC in March 2026 [2]. The technology and engineering expertise developed through the Valkyrie program have also contributed to commercial humanoid robotics, most notably through Apptronik's Apollo robot, whose founders were members of the original Valkyrie team [3].
NASA's humanoid robotics program traces its origins to 1997, when the Robot Systems Technology Branch at Johnson Space Center began developing the first Robonaut (R1) in collaboration with DARPA. R1 was an upper-body humanoid designed to demonstrate that a robotic assistant could perform maintenance tasks typically requiring human dexterity. The robot featured 43 degrees of freedom, including two 7-DOF arms and two dexterous 5-fingered hands with 14 DOF each. Through 2006, R1 was tested extensively in laboratory and field environments using various lower-body configurations, including a wheeled Segway-based platform (Robotic Mobility Platform) and a four-wheeled Centaur base [4].
In 2007, NASA signed a Space Act Agreement with General Motors to co-develop the next-generation Robonaut 2 (R2). Unveiled in February 2010, R2 was faster, more dexterous, and more technologically advanced than R1. On February 24, 2011, Robonaut 2 launched to the International Space Station aboard the Space Shuttle Discovery's final mission (STS-133), becoming the first humanoid robot to operate in space. R2 conducted robotics research on the ISS from 2012 onward, and the original upper-body unit was later upgraded with climbing manipulator "legs," more capable processors, and new sensors. In April 2018, NASA announced that R2 would return to Earth for repairs and eventual relaunch [4][5].
The Robonaut program provided JSC engineers with deep expertise in humanoid manipulation, dexterous end effectors, and human-robot interaction. Valkyrie drew upon this accumulated knowledge but represented a fundamentally different approach: rather than an upper-body workspace assistant, Valkyrie would be a complete, self-contained bipedal platform capable of navigating and operating in unstructured environments.
The design of Valkyrie began in October 2012, driven by NASA's decision to enter the DARPA Robotics Challenge. The DRC was organized in response to the 2011 Fukushima Daiichi nuclear disaster in Japan, which highlighted the need for robots capable of operating in environments too dangerous for humans. DARPA offered substantial prize money and funding to teams that could develop robots capable of performing disaster-response tasks such as driving vehicles, traversing debris, climbing ladders, using tools, and opening doors [6].
Team leader Nicolaus Radford organized the JSC effort using a model inspired by Lockheed's legendary Skunk Works program: a diverse, cross-disciplinary group working together under one roof in tight secrecy. NASA hired approximately 20 new engineers, some fresh out of college, bringing the total Valkyrie team to roughly 55 people. The team worked in partnership with the University of Texas at Austin and Texas A&M University [1][7].
The prototype was completed by July 2013, representing an extraordinarily compressed development cycle of approximately nine months from concept to hardware. Valkyrie was publicly unveiled in December 2013, just before the DRC Trials. The rapid timeline was intentional: Radford and his team sought to demonstrate that NASA could design and build a sophisticated humanoid robot on an aggressive schedule, a capability relevant to future space exploration programs where rapid hardware iteration may be essential [7].
Valkyrie stands 188 cm (6 feet 2 inches) tall and weighs approximately 125 kg (300 pounds). The robot's anthropomorphic form factor was chosen so it could operate in spaces designed for humans, using human tools and interfaces. A prominent design feature is the illuminated NASA emblem on the robot's chest, a circular LED ring that provides visual status information and gives Valkyrie its distinctive "superhero" aesthetic [1].
Valkyrie possesses 44 actuated degrees of freedom distributed across its body:
| Body segment | Configuration | DOF |
|---|---|---|
| Neck | 3-DOF rotary | 3 |
| Torso/Waist | 2 linear SEA (pitch, roll) + 1 rotary SEA (yaw) | 3 |
| Each arm (upper) | 4 series elastic rotary actuators | 4 x 2 = 8 |
| Each wrist | 3-DOF | 3 x 2 = 6 |
| Each hand | 3 fingers + thumb, 4 actuators | 4 x 2 = 8 |
| Each leg (upper) | 5 series elastic rotary actuators (yaw-roll-pitch-pitch-pitch) | 5 x 2 = 10 |
| Each ankle | 2 series elastic linear actuators (pitch-roll) | 2 x 2 = 4 |
| Neck subtotal | 3 | |
| Total | 44 |
The leg configuration follows a yaw-roll-pitch-pitch-pitch-roll arrangement, with the first three hip joints and the knee joint implemented as rotary series elastic actuators. The ankle is realized using two parallel linear actuators working in concert to produce pitch and roll motion [7][8].
Valkyrie's defining engineering feature is its use of series elastic actuators (SEAs) throughout the entire robot. Unlike traditional stiff position-controlled actuators, SEAs incorporate a compliant spring element between the motor and the joint output. This spring serves multiple purposes: it provides mechanical shock absorption, enables accurate torque sensing by measuring spring deflection, and inherently limits the force the actuator can apply, making the robot safer for interaction with humans and unpredictable environments [8][9].
The robot employs two types of SEAs:
| Actuator type | Location | Mechanism |
|---|---|---|
| Rotary SEA | Arms, legs (hip, knee), waist yaw, neck | Motor drives through a spring to a rotary joint output; spring deflection measured for torque feedback |
| Linear SEA | Ankles, waist (pitch and roll) | Motor drives a ball screw through a spring to a linear output; used where compact linear force is needed |
The series elastic architecture enables a decentralized torque control strategy where each joint runs its own closed-loop torque controller. A multi-joint controller sends desired torques to individual single-joint controllers, along with desired position, velocity, stiffness, damping, and gravity compensation parameters. This approach extends the torque bandwidth from approximately 13 Hz (open-loop) to 70 Hz (closed-loop), representing a significant improvement in control fidelity [9].
The compliant torque control enabled by the SEAs allows Valkyrie to perform whole-body impedance control, meaning the robot can modulate how stiff or compliant each joint feels to external forces. This is critical for tasks requiring contact with the environment, such as pushing against a wall, grasping objects, or maintaining balance on uneven terrain. During demonstrations, low torque tracking errors have been maintained even during physical human-robot interaction, where a person pushes or guides the robot's limbs [9].
One of Valkyrie's most innovative design features is its modular architecture. The robot treats each arm, each leg, the pelvis, and the torso as functionally equivalent "limbs," each of which can be removed with a single mechanical connector and one bolt. This hot-swappable design serves several purposes [7][10]:
The quick-disconnect interfaces include both mechanical coupling and electrical connectors, allowing a replacement limb to be fully operational immediately upon attachment.
Valkyrie's hands feature a simplified humanoid design with three fingers and a thumb. Each forearm contains six actuators that drive the hand's four degrees of freedom. While less dexterous than the 14-DOF hands of Robonaut 2, the simplified design was chosen to improve reliability and durability for the physically demanding tasks encountered in disaster-response scenarios. Following the DRC Trials, the hands were further redesigned to increase their robustness [7][10].
Valkyrie carries a comprehensive array of sensors for perceiving its environment:
| Sensor | Location | Function |
|---|---|---|
| Carnegie Robotics MultiSense SL | Head | Primary perception sensor; provides spinning LiDAR, passive stereo cameras, and modified IR structured light for 3D point cloud generation |
| Hazard cameras (fore and aft) | Torso (front and back) | Wide-angle situational awareness |
| Joint torque sensors | All series elastic actuators | Measure spring deflection for closed-loop torque control |
| Force/torque sensors | Wrists and ankles | Contact force measurement for manipulation and balance |
| IMU (Inertial Measurement Unit) | Pelvis | Body orientation and acceleration sensing |
The MultiSense SL head unit, developed by Carnegie Robotics, is the same sensor package used on the Boston Dynamics Atlas robot. The head sits atop a 3-DOF neck that allows the sensor suite to pan, tilt, and rotate independently of the body. The IR structured light capability was a modification added specifically for Valkyrie, supplementing the laser and passive stereo methods already present in the standard MultiSense SL [7][10].
The robot's face features an infrared-transparent faceplate behind which the LiDAR unit continuously scans the surroundings, giving Valkyrie a 360-degree perception capability when combined with head rotation [10].
Valkyrie's onboard computing consists of two Intel Core i7 processors that handle all perception, planning, and control computations. The robot connects to external systems and operators via Ethernet or Wi-Fi [7].
The robot is powered by a custom dual-voltage lithium-ion battery with a capacity of 1.8 kWh, housed in a backpack-style enclosure on the robot's back. The battery provides approximately one hour of autonomous operation. Valkyrie can also run from wall power during laboratory testing. The backpack battery is hot-swappable: a human operator can remove a spent battery and insert a fresh one in a matter of minutes, minimizing downtime. When a battery is not in use, it can be replaced with a mass simulator and capacitor that replicates the mechanical and some electrical properties of the battery, allowing testing without consuming battery cycles [7][10].
| Category | Specification | Value |
|---|---|---|
| Physical | Height | 188 cm (6 ft 2 in) |
| Physical | Weight | 125 kg (300 lb) |
| Physical | Build | Aluminum, steel, polycarbonate |
| Mobility | Total degrees of freedom | 44 |
| Mobility | Arm DOF (each) | 7 (4 upper arm + 3 wrist) |
| Mobility | Hand DOF (each) | 4 (3 fingers + thumb) |
| Mobility | Leg DOF (each) | 6 (5 rotary + 1 ankle) + 1 ankle roll |
| Mobility | Waist DOF | 3 (pitch, roll, yaw) |
| Mobility | Neck DOF | 3 |
| Actuation | Type | Series elastic actuators (rotary and linear) |
| Actuation | Torque bandwidth | ~70 Hz (closed-loop) |
| Sensing | Head sensor | Carnegie Robotics MultiSense SL (LiDAR + stereo + IR) |
| Sensing | Body cameras | Fore and aft hazard cameras |
| Computing | Processors | 2 x Intel Core i7 |
| Computing | Connectivity | Ethernet, Wi-Fi |
| Power | Battery capacity | 1.8 kWh (dual-voltage lithium-ion) |
| Power | Operating time | ~1 hour |
| Power | Battery swap | Hot-swappable backpack |
| Cost | Per unit | ~$2 million |
The DARPA Robotics Challenge Trials took place on December 20 and 21, 2013, at the Homestead-Miami Speedway in Florida. Sixteen teams competed across eight tasks designed to simulate disaster-response operations: driving a vehicle, walking over debris, climbing a ladder, removing debris, opening doors, closing valves, connecting a fire hose, and crossing terrain [6].
Valkyrie entered as a Track A competitor, meaning NASA had built its own hardware rather than using a DARPA-provided Atlas robot. The DRC Trials proved deeply disappointing for the Valkyrie team. The robot scored zero points across all attempted tasks, placing in a three-way tie for last among the 16 competitors [6][11].
The root cause of Valkyrie's failure at the DRC Trials was not mechanical but a software communications error. A network traffic-shaping tool that the team had added to their code inadvertently blocked data transmission from the operator station to the robot. This manifested as a major instability in the control system, rendering the robot nearly inoperable for most of Day 1 of the competition [11].
The networking issue was identified and fixed in time for the last event of Day 1 (the door-opening task), but by then the bulk of Valkyrie's scoring opportunities had passed. During practice runs at JSC in the weeks before the competition, the robot had been reliably scoring 6 to 8 points on mock DRC tasks. Had the easier tasks been scheduled on the second day rather than the first, the team would have had time to diagnose the issue before attempting the higher-value challenges [11].
Despite the zero-point result, the Valkyrie team gained valuable lessons. The competition exposed weaknesses in the robot's operational readiness that would not have been apparent in the controlled laboratory environment at JSC.
| Rank | Team | Robot | Score (points) |
|---|---|---|---|
| 1 | SCHAFT | SCHAFT robot | 27 |
| 2 | IHMC Robotics | Atlas | 20 |
| 3 | Tartan Rescue | CHIMP | 18 |
| 4 | MIT | Atlas | 16 |
| 5 | RoboSimian | RoboSimian | 14 |
| 6 | TRACLabs | Atlas | 11 |
| 7 | WRECS | Atlas | 11 |
| 8 | KAIST | DRC-Hubo | 8 |
| ... | ... | ... | ... |
| 14 (tied) | NASA-JSC | Valkyrie | 0 |
Following the DRC Trials, the Valkyrie team undertook a comprehensive upgrade program. Key improvements included [10][11]:
NASA did not enter Valkyrie in the 2015 DRC Finals, choosing instead to focus on long-term development of the platform for space exploration applications.
In mid-2015, NASA announced a competition to award upgraded Valkyrie robots to academic research groups. The goal was to accelerate the development of software and algorithms for humanoid robots that could support future space exploration missions. Two groups won the competition [12][13]:
Both institutions were tasked with developing software for autonomous and supervised operation of humanoid robots in space exploration scenarios.
A third Valkyrie unit was delivered to the University of Edinburgh in Scotland in 2016, making it the only R5 operating outside the United States. The robot was hosted at the Edinburgh Centre for Robotics, a joint initiative between the University of Edinburgh and Heriot-Watt University. Over the following decade, Valkyrie served as a research platform for dozens of PhD students and researchers working on humanoid control, motion planning, and perception [2][14].
Key research achievements during Valkyrie's Edinburgh residency included:
Dr. Vladimir Ivan, who led much of the Edinburgh research, described hosting the robot as "a rare privilege...giving us a unique opportunity to advance fundamental research in mobility and stability" [2].
In March 2026, after a full 10 years at the university, Valkyrie was returned to NASA's Johnson Space Center. The University of Edinburgh continues humanoid robotics research using a PAL Robotics Talos robot acquired in 2020 [2].
The Florida Institute for Human and Machine Cognition (IHMC), based in Pensacola, Florida, has been a central partner in Valkyrie's development. IHMC's expertise in bipedal locomotion, previously demonstrated through their strong DRC performance (second place at the 2013 Trials), proved invaluable. IHMC implemented their whole-body walking controller on the Valkyrie platform, providing the core locomotion software that enabled reliable bipedal walking [10][15].
The collaboration extended to shared software infrastructure. The research partners built on a common software base that included a Drake-based user interface (developed at MIT), IHMC's Simulation Construction Set (SCS) for lower-body control, and Edinburgh's Exotica motion planner for task execution. This shared codebase allowed all four partners (NASA, MIT, IHMC, and Edinburgh) to contribute improvements that benefited the entire Valkyrie research community [15].
NASA's long-term vision for Valkyrie centers on the concept of robotic precursor missions. In this scenario, humanoid robots would be sent to planetary surfaces, such as Mars, well in advance of human crews. These robots would perform preparatory tasks that would otherwise require astronauts to work in spacesuits, including [16]:
The use of a humanoid form factor is central to this strategy. Because the habitats, tools, and equipment are designed for human use, a robot with a human-like body plan can interact with these systems without requiring custom robotic interfaces. A humanoid robot can turn the same valves, flip the same switches, and walk through the same doors that astronauts will eventually use [16].
To advance autonomous software for planetary surface operations, NASA launched the Space Robotics Challenge (SRC), a virtual competition using a simulated Valkyrie robot in the Gazebo simulation environment. Competitors developed software to guide a virtual Valkyrie through tasks representative of post-disaster repair on a Mars habitat [17].
In the SRC Phase 1 finals, held in 2017, a simulated Valkyrie had to perform three tasks after a dust storm damaged a Martian base: aligning a communications dish, repairing a solar array, and locating and fixing a leak in the habitat. The competition was won by Coordinated Robotics, a one-person team from California that achieved a perfect run with 100 percent task completion, earning the $125,000 top prize plus a $50,000 bonus for the perfect score [17].
SRC Phase 2 shifted focus to lunar surface operations with a different robot platform, but the foundational work on autonomous decision-making and task planning from Phase 1 continued to inform Valkyrie's development.
In 2023, NASA announced a reimbursable Space Act Agreement with Woodside Energy, an Australian energy company headquartered in Perth, Western Australia. Under this agreement, a Valkyrie robot was shipped to Australia in July 2023 to test remote mobile dexterous manipulation capabilities at Woodside's facilities. The goal was to evaluate whether a humanoid robot could handle remote caretaking operations on uncrewed offshore energy platforms [18].
The partnership serves dual purposes. For Woodside, it explores the potential for humanoid robots to improve safety and efficiency in hazardous offshore environments where human access is difficult. For NASA, it provides real-world operational experience in dirty and harsh conditions analogous to those found on the Moon at future Artemis mission worksites. NASA plans to apply software and operational insights from the Woodside collaboration to upcoming hardware releases, with operational demonstrations planned for 2026 and 2027 [18].
The Valkyrie program's most significant commercial spinoff is Apptronik, a robotics company founded in Austin, Texas. Apptronik's co-founder and CTO, Nick Paine, was a member of the original NASA-JSC Valkyrie DRC team. While pursuing his PhD at the University of Texas under Professor Luis Sentis, Paine joined the JSC team in 2011 to build Valkyrie's actuators and control systems. His doctoral research on series elastic actuator control for Valkyrie was published in the Journal of Field Robotics and became a foundational reference in the field [3][9].
Apptronik's first contracts were with NASA to develop next-generation actuation and control systems. The company later unveiled Apollo, a general-purpose humanoid robot designed for commercial applications in logistics and manufacturing. Apollo's design philosophy, particularly its modular architecture and series elastic actuation, traces directly to lessons learned from Valkyrie. Apollo robots have been deployed at Mercedes-Benz manufacturing facilities and other industrial settings. By early 2026, Apptronik had raised over $935 million in total funding at a valuation exceeding $5 billion, with investors including Google, Mercedes-Benz, and the Qatar Investment Authority [3][19].
Valkyrie has contributed several important advances to the broader field of humanoid robotics:
| Robot | Designation | Year | Type | Key milestone |
|---|---|---|---|---|
| Robonaut 1 | R1 | 2000 | Upper-body torso | First NASA humanoid; 43 DOF; proved dexterous manipulation concept |
| Robonaut 2 | R2 | 2010 | Upper-body torso (later with legs) | First humanoid robot in space (ISS, 2011); GM partnership |
| Valkyrie | R5 | 2013 | Full bipedal humanoid | First NASA bipedal humanoid; 44 DOF; SEA architecture; DRC competitor |
Despite its engineering sophistication, Valkyrie faces several practical limitations that reflect the broader challenges of humanoid robotics:
As of early 2026, the University of Edinburgh's Valkyrie unit has been returned to NASA JSC after its 10-year research deployment [2]. NASA continues to develop software and operational concepts using Valkyrie, with planned demonstrations alongside Woodside Energy in Australia during 2026 and 2027 [18]. The agency has indicated that lessons learned from the Valkyrie program will be applied to next-generation hardware as part of its broader strategy for robotic support of Artemis lunar missions and eventual human exploration of Mars.
The Valkyrie program remains active as both a physical research platform and a conceptual framework for NASA's vision of humanoid robots as partners in space exploration. While the robot's hardware is aging, the software, control algorithms, and operational experience developed around Valkyrie continue to advance through partnerships with IHMC, university collaborators, and commercial entities like Apptronik.