PASADENA (JPL) – NASA is on the hunt for an asteroid to capture with a robotic spacecraft, redirect to a stable orbit around the moon, and send astronauts to study in the 2020s — all on the agency’s human Path to Mars. Agency officials announced on Thursday, June 19, recent progress to identify candidate asteroids for its Asteroid Redirect Mission (ARM), increase public participation in the search for asteroids, and advance the mission’s design.
NASA plans to launch the ARM robotic spacecraft in 2019 and will make a final choice of the asteroid for the mission about a year before the spacecraft launches. NASA is working on two concepts for the mission: The first is to fully capture a very small asteroid in open space, and the second is to collect a boulder-sized sample off of a much larger asteroid. Both concepts would require redirecting an asteroid less than 32 feet (10 meters) in size into the moon’s orbit. The agency will choose between these two concepts in late 2014 and further refine the mission’s design.
The agency will award a total of $4.9 million for concept studies addressing components of ARM. Proposals for the concept studies were solicited through a Broad Agency Announcement (BAA) released in March, and selected in collaboration with NASA’s Space Technology and Human Exploration and Operations Mission Directorates. The studies will be completed over a six-month period beginning in July, during which time system concepts and key technologies needed for ARM will be refined and matured. The studies also will include an assessment of the feasibility of potential commercial partners to support the robotic mission.
“With these system concept studies, we are taking the next steps to develop capabilities needed to send humans deeper into space than ever before, and ultimately to Mars, while testing new techniques to protect Earth from asteroids,” said William Gerstenmaier, associate administrator for NASA’s Human Exploration and Operations Mission Directorate.
For more information about the BAA and award recipients, visit:
NASA’s Spitzer Space Telescope made recent observations of an asteroid designated 2011 MD, which bears the characteristics of a good candidate for the full capture concept. While NASA will continue to look for other candidate asteroids during the next few years as the mission develops, astronomers are making progress to find suitable candidate asteroids for humanity’s next destination into the solar system.
“Observing these elusive remnants that may date from the formation of our solar system as they come close to Earth is expanding our understanding of our world and the space it resides in,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate. “Closer study of these objects challenges our capabilities for future exploration and will help us test ways to protect our planet from impact. The Spitzer observatory is one of our tools to identify and characterize potential candidate targets for the asteroid mission.”
Analysis of Spitzer’s infrared data shows 2011 MD is roughly 20 feet (6 meters) in size and has a remarkably low density — about the same as water, which supports the analysis of observations taken in 2011.
The asteroid appears to have a structure perhaps resembling a pile of rocks, or a “rubble pile.” Since solid rock is about three times as dense as water, this suggests about two-thirds of the asteroid must be empty space. The research team behind the observation says the asteroid could be a collection of small rocks, held loosely together by gravity, or it may be one solid rock with a surrounding halo of small particles. In both cases, the asteroid mass could be captured by the ARM capture mechanism and redirected into lunar orbit.
The findings based on the Spitzer observation were published Thursday in the Astrophysical Journal Letters. For more information, visit:
To date, nine asteroids have been identified as potential candidates for the mission, having favorable orbits and measuring the right size for the ARM full capture option. With these Spitzer findings on 2011 MD, sizes now have been established for three of the nine candidates. Another asteroid — 2008 HU4 — will pass close enough to Earth in 2016 for interplanetary radar to determine some of its characteristics, such as size, shape and rotation. The other five will not get close enough to be observed again before the final mission selection, but NASA’s Near-Earth Object (NEO) Program is finding several potential candidate asteroids per year. One or two of these get close enough to Earth each year to be well characterized.
Boulders have been directly imaged on all larger asteroids visited by spacecraft so far, making retrieval of a large boulder a viable concept for ARM. During the next few years, NASA expects to add several candidates for this option, including asteroid Bennu, which will be imaged up close by the agency’s Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer (OSIRIS-REx) mission in 2018.
NASA’s search for candidate asteroids for ARM is a component of the agency’s existing efforts to identify all NEOs that could pose a threat to the Earth. Some of these NEOs could become candidates for ARM because they are in orbits similar to Earth’s. More than 11,140 NEOs have been discovered as of June 9. Approximately 1,483 of those have been classified as potentially hazardous.
In June 2013, NASA announced an Asteroid Grand Challenge (AGC) to accelerate this observation work through non-traditional collaborations and partnerships. On the first anniversary of the grand challenge this week, NASA officials announced new ways the public can contribute to the Asteroid Grand Challenge, building on the successes of the challenge to date. To that end, NASA will host a two-day virtual workshop — dates to be determined — on emerging opportunities through the grand challenge, in which the public can participate.
“There are great ways for the public to help with our work to identify potentially hazardous asteroids,” said Jason Kessler, program executive for NASA’s Asteroid Grand Challenge. “By tapping into the innovative spirit of people around the world, new public-private partnerships can help make Earth a safer place, and perhaps even provide valuable information about the asteroid that astronauts will visit.”
For more information about the workshop and public opportunities through the grand challenge, visit:
The Asteroid Grand Challenge and Asteroid Redirect Mission comprise NASA’s Asteroid Initiative. Capabilities advanced and tested through the Asteroid Initiative will help astronauts reach Mars in the 2030s. For more information about the Asteroid Initiative and NASA’s human Path to Mars, visit:
http://www.nasa.gov/asteroidinitiative
Big question, if they are successful in doing this, what do they hope to discover or research, that will help our planet? My mind boggles
Here is a useful summary of some low delta-v asteroid potential targets.
http://www.permanent.com/space-transportation-asteroids.html
I am extremely skeptical about the feasibility, much less the affordability, of asteroid capture.
That said, let’s take a 1000 ton, 10 m diameter ball. 10*6 kg. Let us further assume we only need 60 m/s to initiate a lunar gravity assist capture (on some unknown date). (Note: 1982DB is a diameter of 330 meters (about 3 billion tons), but let’s assume we can find a small one.).
1000 tons * 60m/s
We must still give an impulse of 60 million kg-m/s.
The rocket engine under development with the greatest specific impulse is the Dual Stage 4-Grid Ion Thruster with a 19,000 m/s specific impulse (N-s/kg). To shove this 1000 ton ball 60 m/s would take
Impulse Needed (mv) = 60,000,000. kg-m/sec
Specific Impulse Dual Grid Ion = 19,000. m/sec
Minimum Propellant Xenon = 3,158. kg (delivered to asteroid)
Force of Ion Drive = 2.5 N
acceleration of Asteroid = 2.50E-06 m/sec2
Number sec to reach Delta-V = 2.40E+07 sec
Number of sec/day = 8.64E+04 sec/day
Number of days to reach Delta-V = 278. days Do able!
Mass solar panels (assumption) = 10. kg/kW
Power of Dual Grid Ion = 250. kW
Mass of solar Panels = 2500. kg
Dry weight of craft = 1000. kg (assumption)
loaded weight of craft (dry+solar+prop) = 6658. kg at Rendezvous
Delta-v from LEO to Rendezvous = 4000. m/sec (Escape 3200 + 800 m/s inter orbit assumption)
Impulse from LEO to Rendezvous = 2.66E+07 kg-m/sec
Isp = 19000. m/sec
mass of propellant LEO to Rendezvous = 1402. kg. (+20% to lift that prop.)
Est mass of craft at Dep = 8340. kg
Cost to LEO = $25,000 / kg
Cost of craft to LEO = $208 million + Development.
Hey a bargain!
But let’s remember, this was a 1000 ton, 10 m diameter ball we only had to push 60 m/s to achieve a lunar gravity assist capture at the optimum day and “phase of the moon.”
Most of the opportunities needed Delta-V’s of over 1000 m/s delta-V.
If 1200 m/s delta-v is needed,
then we are probably talking about at least two crafts, working simultaneously,
each with 40,000 kg of Xenon Propellant, burning for 8 years
each craft weighing 46,000 kg
Costing $2.4 Billion to get the both craft into LEO.
I note that we use about 100,000 kg of fuel to move a lucky 1,000,000 kg asteroid into a high earth orbit.
If you used the Dawn type of Ion Thruster, Isp = 1900 m/s, then each craft would be 1,190,000 kg and would cost $30 billion each. The propellant would by 2 times as much mass as the asteroid.
If you wanted to use high thrust hypergolic fuel, Isp -300, then each craft would carry 36 million kg of fuel and it would cost $9 trillion — each.
Ric Werme says: June 22, 2014 at 2:53 pm Oh heavens, it’s all covered in Heinlein’s The Moon Is a Harsh Mistress,
Thanks, Ric for the title reminder. Just ordered it from my local Library.
Stephen – instead of wasting all that fuel, better to set up sail on the asteroid and use light pressure from the Sun – plus the Solar Wing as appropriate – to manouevre the asteroid into near space. But to finally get it into a suitable orbit you would probably have to use a nuclear power plant heating bits of the asteroid in an “ion drive” No point in taking umpteen tonnes of ‘fuel’ when there are bits of asteroid you could use.
David Ball says:
June 21, 2014 at 5:49 pm
Precisely stated!
Latitude says:
June 21, 2014 at 5:52 pm
Latitude,
Your condescending analogy is crap.
I am not a ‘3 year old’. Nor are the host of other professionals that devoted their careers to aerospace and astrospace excellence.
With political and financial commitment, my predecessors landed humans on the moon in less than 10 years. We built on those successes by developing the space based communications technologies that connect the world communities and drive the world economies today. We put space stations in orbit, developed much more efficient commercial and military aircraft, and sent space craft to explore the corners of our solar system and beyond. We provided the means for you to disparage our life time efforts via those satellites and the world wide web on the page of this blog and others.
No thanks are necessary. It’s just what good scientists and engineers do……. everyday.
Advancing technology to make human life easier and better is what we do.
Mac
@Dudley Horscroft at 10:16 pm
better to set up sail on the asteroid and use light pressure from the Sun – plus the Solar Wing as appropriate – to manouevre the asteroid into near space. …. No point in taking umpteen tonnes of ‘fuel’ when there are bits of asteroid you could use.
First, my point was how utterly idiotic it is to try to change the orbit of a 1000 ton asteroid. I was focused on 500 m/s to 2000 m/s delta-v necessary. My research brought out the possibility of sub 200 m/s delta-v if we are very lucky at finding small asteroids and VERY patient at waiting for one opportunity to deflect it to where it must be.
How much force can you get with a solar sail?
The total force exerted on an 800 by 800 meter solar sail, for example, is about 5 newtons (1.1 lbf) at Earth’s distance from Sol,[2] making it a low-thrust propulsion system, similar to spacecraft propelled by electric engines (Wikipedia)
Ok. That is about the same force as we can get from DS4S Ion drive. The DS4S is under development, but there have been several one stage Ion drives with years of operational experience. There has yet to be a solar sail of any size deployed that has proven propulsion — only for deorbit via atmospheric drag. Nothing even 1% the size of that sail has been deployed even temporarily, much less for years.
But a big problem is that that force is available in limited directions. You cannot get a net force on the sale with a component toward the sun.
As for using the asteroid itself as reaction mass, that would be great Why bring up tons of Xenon from Earth when we have tons of… ?What? at the asteroid? Why? Because with Xenon, we can get a propellant velocity of 19,000 m/s.
Ok, we can’t throw rocks at 19,000 m/s. but we have so many more rocks! What kind of rock? How solid? How do you throw it? How do you mine the asteroid when it is so small it has virtually no gravity? How do you create and maintain a weightless mining operation completely autonomously? .
Maybe we just send up a robotic Alan Shepard with a golf club and it just keeps swinging at pebbles. If you have 1000 tons of rock, and you can launch it away electromachanically at 100 m/s, you will have to throw away about 1/2 the rock just to get the other half to change by 60 m/s.
Using the asteroid as reaction mass would be ideal. But it is an engineering nightmare. TANSTAAFL.
P.S. The Moon is a Harsh Mistress is a favorite book.
I was just on a long trip and had playing on Audio books: Starship Troopers, Moon is a Harsh Mistress, and Stranger in a Strange Land. Hard to believe these three came from the same pen in a span of 7 years.