Boulder Extraction and Robotic Arm Mechanisms For NASA’s Asteroid Redirect Mission Start Rigorous Testing at NASA Goddard

NASA GODDARD SPACE FLIGHT CENTER, MD – Rigorous testing has begun on the advanced robotic arm and boulder extraction mechanisms that are key components of the unmanned probe at the heart of NASA’s Asteroid Redirect Robotic Mission (ARRM) now under development to pluck a multi-ton boulder off a near-Earth asteroid so that astronauts visiting later in an Orion crew capsule can harvest a large quantity of samples for high powered scientific analysis back on Earth. Universe Today inspected the robotic arm hardware utilizing “leveraged robotic technology” during an up close visit and exclusive interview with the engineering development team at NASA Goddard.

“The teams are making great progress on the capture mechanism that has been delivered to the robotics team at Goddard from Langley,” NASA Associate Administrator Robert Lightfoot told Universe Today.

“NASA is developing these common technologies for a suite of missions like satellite servicing and refueling in low Earth orbit as well as autonomously capturing an asteroid about 100 million miles away,” said Ben Reed, NASA Satellite Servicing Capabilities Office (SSCO) Deputy Project Manager, during an exclusive interview and hardware tour with Universe Today at NASA Goddard in Greenbelt, Maryland, regarding concepts and goals for the overall Asteroid Redirect Mission (ARM) initiative.

NASA is leveraging technology originally developed for satellite servicing such as with the Robotic Refueling Mission (RRM) currently on board the International Space Station (ISS) and repurposing them for the asteroid retrieval mission.

“Those are our two near term mission objectives that we are developing these technologies for,” Reed explained.

ARRM combines both robotic and human missions to advance the new technologies required for NASA’s agency wide ‘Journey to Mars’ objective of sending a human mission to the Martian system in the 2030s.

The unmanned Asteroid Redirect Robotic Mission (ARRM) to grab a boulder is the essential first step towards carrying out the follow on sample retrieval with the manned Orion Asteroid Redirect Mission (ARM) by the mid-2020s.

ARRM will use a pair of highly capable robotic arms to autonomously grapple a multi-ton (> 20 ton) boulder off the surface of a large near-Earth asteroid and transport it to a stable, astronaut accessible orbit around the Moon in cislunar space.

“Things are moving well. The teams have made really tremendous progress on the robotic arm and capture mechanism,” Bill Gerstenmaier, NASA Associate Administrator for Human Exploration and Operations, told Universe Today.

Then an Orion crew capsule can fly to it and the astronauts will collect a large quantity of rock samples and gather additional scientific measurements.

“We are working on a system to rendezvous, capture and service different [target] clients using the same technologies. That is what we are working on in a nut shell,” Reed said.

This engineering design unit of the robotic servicing arm is under development to autonomously extract a boulder off an asteroid for NASA’s asteroid retrieval mission and  is being tested at NASA Goddard.   It has seven degrees of freedom and mimics a human arm.   Credit: Ken Kremer/kenkremer.com
This engineering design unit of the robotic servicing arm is under development to autonomously extract a boulder off an asteroid for NASA’s asteroid retrieval mission and is being tested at NASA Goddard. It has seven degrees of freedom and mimics a human arm. Credit: Ken Kremer/kenkremer.com

“Right now the plan is to launch ARRM by about December 2020,” Reed told me. But a huge amount of preparatory work across the US is required to turn NASA’s plan into reality.

Key mission enabling technologies are being tested right now with a new full scale engineering model of the ‘Robotic Servicing Arm’ and a full scale mockup of the boulder snatching ARRM Capture Module at NASA Goddard, in a new facility known as “The Cauldron.”

Capture Module comprising two robotic servicing arms and three boulder grappling contact and restraint system legs for NASA’s Asteroid Redirect Robotic Mission (ARRM).   Credit: NASA
Capture Module comprising two robotic servicing arms and three boulder grappling contact and restraint system legs for NASA’s Asteroid Redirect Robotic Mission (ARRM). Credit: NASA
The ARRM capture module is comprised of two shorter robotic arms (separated by 180 degrees) and three lengthy contact and restraint system capture legs (separated by 120 degrees) attached to a cradle with associated avionics, computers and electronics and the rest of the spacecraft and solar electric power arrays.

“The robotic arm we have here now is an engineering development unit. The 2.2 meter-long arms can be used for assembling large telescopes, repairing a failed satellite, removing orbital debris and capturing an asteroid,” said Reed.

“There are two little arms and three big capture legs.”

“So, we are leveraging one technology development program into multiple NASA objectives.”

“We are working on common technologies that can service a legacy orbiting satellite, not designed to be serviced, and use those same technologies with some tweaking that we can go out with 100 million miles and capture an asteroid and bring it back to the vicinity of the Moon.”

“Currently the [capture module] system can handle a boulder that’s up to about 3 x 4 x 5 meters in diameter.”

Artists concept of NASA’s Asteroid Redirect Robotic Mission capturing an asteroid boulder before redirecting it to a astronaut-accessible orbit around Earth's moon.  Credits: NASA
Artists concept of NASA’s Asteroid Redirect Robotic Mission capturing an asteroid boulder before redirecting it to a astronaut-accessible orbit around Earth’s moon. Credits: NASA

The Cauldron is a brand new Goddard facility for testing technologies and operations for multiple exploration and science missions, including satellite servicing and ARRM that just opened in June 2015 for the centers Satellite Servicing Capabilities Office.

Overall project lead for ARRM is the Jet Propulsion Laboratory (JPL) with numerous contributions from other NASA centers and industrial partners.

“This is an immersive development lab where we bring systems together and can do lifetime testing to simulate what’s in space. This is our robotic equivalent to the astronauts NBL, or neutral buoyancy lab,” Reed elaborated.

“So with this same robotic arm that can cut wires and thermal blankets and refuel an Earth sensing satellite, we can now have that same arm go out on a different mission and be able to travel out and pick up a multi-ton boulder and bring it back for astronauts to harvest samples from.”

“So that’s quite a technical feat!”

The Robotic Servicing Arm is a multi-jointed powerhouse designed to function like a “human arm” as much as possible. It builds on extensive prior research and development investment efforts conducted for NASA’s current Red Planet rovers and a flight-qualified robotic arm developed for the Defense Advanced Research Projects Agency (DARPA).

“The arm is capable of seven-degrees-of-freedom to mimic the full functionally of a human arm. It has heritage from the arm on Mars right now on Curiosity as well as ground based programs from DARPA,” Reed told me.

“It has three degrees of freedom at our shoulder, two at our elbow and two more at the wrist. So I can hold the hand still and move the elbow.”

The arm will also be equipped with a variety of interchangeable “hands” that are basically tools to carry out different tasks with the asteroid such as grappling, drilling, sample gathering, imaging and spectrometric analysis, etc.

View of the robotic arm above and gripper tool below that initially grabs the asteroid boulder before the capture legs wrap around as planned for NASA’s upcoming unmanned ARRM Asteroid Redirect Robotic Mission that will later dock with an Orion crew vehicle. Credit: Ken Kremer/kenkremer.com
View of the robotic arm above and gripper tool below that initially grabs the asteroid boulder before the capture legs wrap around as planned for NASA’s upcoming unmanned ARRM Asteroid Redirect Robotic Mission that will later dock with an Orion crew vehicle. Credit: Ken Kremer/kenkremer.com

The ARRM spacecraft will carefully study, characterize and photograph the asteroid in great detail for about a month before attempting the boulder capture.

Why does the arm need all this human-like capability?

“When we arrive at an asteroid that’s 100 million miles away, we are not going to know the fine local geometry until we arrive,” Reed explained to Universe Today.

“Therefore we need a flexible enough arm that can accommodate local geometries at the multi-foot scale. And then a gripper tool that can handle those geometry facets at a much smaller scale.”

“Therefore we chose seven-degrees-of-freedom to mimic humans very much by design. We also need seven-degrees-of-freedom to conduct collision avoidance maneuvers. You can’t do that with a six-degree-of-freedom arm. It has to be seven to be a general purpose arm.”

How will the ARRM capture module work to snatch the boulder off the asteroid?

“So the idea is you come to the mother asteroid and touch down and make contact on the surface. Then you hold that position and the two arms reach out and grab the boulder.”

“Once its grabbed the boulder, then the legs straighten and pull the boulder off the surface.”

“Then the arms nestle the asteroid onto a cradle. And the legs then change from a contact system to become a restraint system. So the legs wrap around the boulder to restrain it for the 100 million mile journey back home.

“After that the little arms can let go – because the legs have wrapped around and are holding the asteroid.”

“So now the arm can also let go of the gripper system and pick up a different tool to do other things. For example they can collect a sample with another tool. And maybe assist an astronaut after the crew arrives.”

“During the 100 million mile journey back to lunar orbit they can be also be preparing the surface and cutting into it for later sample collection by the astronauts.”

Be sure to watch this video animation:

Since the actual asteroid encounter will occur very far away, the boulder grappling will have to be done fully autonomously since there will be no possibility for real time communications.

“The return time for communications is like about 30 minutes. So ‘human in the loop’ control is out of the question.

“Once we get into hover position over the landing site we hit the GO button. Then it will be very much like at Mars and the seven minutes of terror. It will take awhile to find out if it worked.”

Therefore the team at Goddard has already spent years of effort and practice sessions just to get ready for working with the early engineering version of the arm to maximize the probability of a successful capture.

“In this facility we put systems together to try and practice and rehearse and simulate as much of the mission as is realistically possible.”

“It took a lot of effort to get to this point, in the neighborhood of four years to get the simulation to behave correctly in real time with contact dynamics and the robotic systems. So the arm has to touch the boulder with force torque sensors and feed that into a computer to measure that and move the actuators to respond accordingly.”

“So the capture of the boulder is autonomous. The rest is teleoperated from the ground, but not the capture itself.”

How realistic are the rehearsals?

“We are practicing here by reaching out with the arm to grasp the client target using autonomous capture [procedures]. In space the client [target] is floating and maybe tumbling. So when we reach out with the arm to practice autonomous capture we make the client tumble and move – with the inertial properties of the target we are practicing on.”

“Now for known objects like satellites we know the mass precisely. And we can program all that inertial property data in very accurately to give us much more realistic simulations.”

“We learned from all our astronaut servicing experiences in orbit is that the more we know for the simulations, the easier and better the results are for the astronauts during an actual mission because you simulated all the properties.”

“But with this robotic mission to an asteroid there is no backup like astronauts. So we want to practice here at Goddard and simulate the space environment.”

ARRM will launch by the end of 2020 on either an SLS, Delta IV Heavy or a Falcon Heavy. NASA has not yet chosen the launch vehicle.

Several candidate asteroids have already been discovered and NASA has an extensive ongoing program to find more.

Orion crew capsule docks to NASA’s asteroid redirect vehicle grappling captured asteroid boulder orbiting the Moon. Credit: NASA
Orion crew capsule docks to NASA’s asteroid redirect vehicle grappling captured asteroid boulder orbiting the Moon. Credit: NASA

Again, this robotic technology was selected for development for ARRM because it has a lot in common with other objectives like fixing communications satellites, refueling satellites and building large telescopes in the future.

NASA is also developing other critical enabling technologies for the entire ARM project like solar electric propulsion that will be the subject of another article.

Therefore NASA is leveraging one technology development program into multiple spaceflight objectives that will greatly assist its plans to send ‘Humans to Mars’ in the 2030s with the Orion crew module launched by the monster Space Launch System (SLS) rocket.

The maiden uncrewed launch of the Orion/SLS stack is slated for November 2018.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

At NASA Goddard robotics lab Ben Reed/NASA Satellite Servicing Capabilities Office (SSCO) Deputy Project Manager and Ken Kremer/Universe Today discuss the robotic servicing arm and asteroid boulder capture mechanism being tested for NASA’s upcoming unmanned ARRM Asteroid Redirect Robotic Mission that will dock with an Orion crew vehicle in lunar orbit by the mid 2020s for sample return collection. Credit: Ken Kremer/kenkremer.com
At NASA Goddard robotics lab Ben Reed/NASA Satellite Servicing Capabilities Office (SSCO) Deputy Project Manager and Ken Kremer/Universe Today discuss the robotic servicing arm and asteroid boulder capture mechanism being tested for NASA’s upcoming unmanned ARRM Asteroid Redirect Robotic Mission that will dock with an Orion crew vehicle in lunar orbit by the mid 2020s for sample return collection. Credit: Ken Kremer/kenkremer.com

A New Look at NASA’s Asteroid Capture Plan

NASA has released some new photos and video animations outlining the concept of how their planned asteroid capture mission will work. The plan is to find, capture, redirect a near-Earth asteroid to a stable point near the Moon in order to explore and study it. As we’ve said previously, it’s still unclear if NASA will receive Congressional funding or authorization to do an asteroid retrieval mission, but the agency is moving ahead with its planning work for now.

NASA recently did a mission formulation review to look at some internal studies on the mission, as well as taking a look at over 400 ideas the space community submitted concerning the mission.

The new images show crew operations including the Orion spacecraft’s trip to and rendezvous with the relocated asteroid, as well as astronauts maneuvering through a spacewalk to collect samples from the asteroid.

You can watch the video and see more images below.


This conceptual image shows NASA’s Orion spacecraft approaching the robotic asteroid capture vehicle. The trip from Earth to the captured asteroid will take Orion and its two-person crew an estimated nine days. Credit: NASA
This conceptual image shows NASA’s Orion spacecraft approaching the robotic asteroid capture vehicle. The trip from Earth to the captured asteroid will take Orion and its two-person crew an estimated nine days. Credit: NASA
In this conceptual image, the two-person crew uses a translation boom to travel from the Orion spacecraft to the captured asteroid during a spacewalk. Credit: NASA.
In this conceptual image, the two-person crew uses a translation boom to travel from the Orion spacecraft to the captured asteroid during a spacewalk. Credit: NASA.
Artist's Concept of a Solar Electric Propulsion System. Credit: Analytical Mechanics Associates
Artist’s Concept of a Solar Electric Propulsion System. Credit: Analytical Mechanics Associates

NASA is also looking at new technologies like a Solar Electric Propulsion System is an essential part of future missions into deep space with larger payloads. The use of advanced SEP offers more mission flexibility, NASA said.

If you’d like to get involved or add your input, NASA will host a technical workshop at the Lunar and Planetary Institute in Houston from Sept. 30 to Oct. 2 to discuss potential ideas. Virtual participation will be available to the public, and when the details of how to participate become available, Universe Today will post an update.

See more images and information on this concept here.

These 12 Asteroids Are The Easiest Ones To Bring Back To Earth

As NASA works through proposals for an asteroid retrieval mission, a new paper shows that there are other research groups considering which asteroids to pick first.

One scientific team has identified 12 “Easily Retrievable Objects” in our solar system that are circling the sun and would not cost too much to retrieve (in relative terms, of course!)

The definition of an ERO is an object that can be captured and brought back to a stable gravitational point near Earth (called a Lagrange point, or more specifically the L1/L2 points between the sun and the Earth.) The change in speed necessary in these objects to make them easily retrievable is “arbitrarily” set at 500 meters per second (1,641 feet/second) or less, the researchers stated.

Image of asteroid Vesta calculated from a shape model, showing a tilted view of the topography of the south polar region. This perspective shows the topography, but removes the overall curvature of Vesta, as if the giant asteroid were flat and not rounded. Credit: NASA
Image of asteroid Vesta calculated from a shape model, showing a tilted view of the topography of the south polar region. This perspective shows the topography, but removes the overall curvature of Vesta, as if the giant asteroid were flat and not rounded. Credit: NASA

Catching the objects wouldn’t just be a technology demonstration, but also could shed some light into how the solar system formed. Asteroids are generally considered leftovers of the early days of the neighborhood; under our current understanding of the solar system’s history, a spinning disc of gas and dust gradually clumped into rocks and other small objects, which eventually crashed into each other and formed planets.

Also, steering these objects around has another benefit: teaching humans how to deflect potentially hazardous asteroids from smacking into the Earth and causing damage. As we were reminded about earlier this year, even smaller rocks such as the one that broke up over a portion of Russia can be hazardous.

Concept of NASA spacecraft with Asteroid capture mechanism deployed to redirect a small space rock to a stable lunar orbit for later study by astronauts aboard Orion crew capsule. Credit: NASA.
Concept of NASA spacecraft with Asteroid capture mechanism deployed to redirect a small space rock to a stable lunar orbit for later study by astronauts aboard Orion crew capsule. Credit: NASA.

There are at least a couple of big limitations to the plan. The first is to make sure not to put the asteroid in a path that would hit the Earth. The second is that he L1 and L2 points are somewhat unstable, so over time the asteroid would drift from its spot. It would need a nudge every so often to keep it in that location.

That said, NASA is taking a serious look at the matter, as well as two groups that would like to mine asteroids: Planetary Resources and Deep Space Industries.

For the curious, this is the complete list of possible asteroids: 2006 RH120, 2010 VQ98, 2007 UN12, 2010 UE51, 2008 EA9, 2011 UD21, 2009 BD, 2008 UA 202, 2011 BL45, 2011 MD, 2000 SG344 and 1991 VG.

More details are available in the paper, “Easily retrievable objects among the NEO population“, which is published in the August 2013 edition of Celestial Mechanics and Dynamical Astronomy. A preprint version is also available on Arxiv.

What’s The Asteroid Capture Mission Going to Look Like? NASA’s Starting Its Review

It’s still unclear if NASA will receive Congressional funding or authorization to do an asteroid retrieval proposal backed by President Barack Obama’s administration, but as missions take time to plan, the agency is moving ahead with its work for now.

NASA just did a mission formulation review this week to look at some internal studies on the mission. It also is starting to wade through hundreds of ideas the space community submitted concerning the mission.

“With the mission formulation review complete, agency officials now will begin integrating the most highly-rated concepts into an asteroid mission baseline concept to further develop in 2014,” NASA stated. The agency was light on details, but more information should be forthcoming when the process is further along.

Concept of Spacecraft with Asteroid Capture Mechanism Deployed. Credit: NASA.
Concept of Spacecraft with Asteroid Capture Mechanism Deployed. Credit: NASA.

The agency’s fiscal 2014 budget proposal suggests robotically picking up an asteroid, steering it closer to Earth, and putting it in a safe orbit where probes and possibly astronauts could visit. The budget is still being moved through Congressional committees and we won’t know until later this year just how much money will be available for NASA, and what initiatives the agency will be allowed to do.

For more information, be sure to read this past article from Universe Today editor Nancy Atkinson looking in detail at NASA’s asteroid retrieval mission. It includes information on what technology could be used, and the history of NASA’s quest to explore asteroids.

Space rocks have hit the headlines several times this year, particularly when one exploded over the area of Chelyabinsk, Russia earlier in 2013. NASA and several other groups have ongoing searches for asteroids and other small bodies in our solar system to catalog and calculate the orbits for as many as they can find. No imminent threats are known.