This area will cover relevant news of the threat to the planet from Near Earth Objects (NEOs) including concepts and designs for mitigation. All opinions are those of the author.

31 January 2007

Ed Lu states the Gravity Tractor can be built for $200-300M

UPDATE (08 February 2007): Ed tells me not to take the $200M-300M figure as an exact estimate for the gravity tractor (potential misquote from the reporter). I think these issues point out that good system designs of actual missions that include all major disciplines (including cost and operations) need to be performed on many asteroid mitigation techniques.


My question: Do we have a mission design that this cost estimate is based on? How was this cost estimate arrived at?

"NASA astronaut and former University of Hawaii solar physicist Edward Lu is calling for a new spacecraft that would divert asteroids on a path to slam into Earth...The small space tractor, costing between $200 million and $300 million, would hover near an asteroid to exert enough gravitational pull that the space rock's orbit would change and a collision with our planet would be averted, Lu said before a crowd packed into a 300-capacity auditorium at the University of Hawaii-Manoa Monday night."

"Astronaut Calls for Asteroid Defense"
Associated Press
25 January 2007

Link: Article

Another reason to attend the 2007 Planetary Defense Conference, also see the current attendees

From my sources, the recent 2007 Planetary Defense Conference will have NASA present the results of its December 2006 report to Congress on the next generation of search and characterization. This should be one of the first public forums where the results of this study will be presented on what Congress should do on Near Earth Object (NEO) detection, characterization, and mitigation.

Also, you can now see the attendees for the conference:

Link: 2007 Planetary Conference Attendees

Article: "Exploding robots may scout hazardous asteroids"

This article was based on a poster session paper presented at the 209th meeting of the American Astronomical Society (AAS) in Seattle, Washington on 07 January 2007. I have listed the paper reference, Ball Aerospace Press Release, and highlights from the article below:

Presentation Number: 025.01
Title: Small Landing Probes for In-situ Characterization of Asteroids and Comets
Authors: Dennis Ebbets, R. Dissly, R. Reinert from Ball Aerospace & Tech. Corp..
Abstract: Future space missions to small solar system objects such as asteroids and comets may include probes that can land to enable characterization of both the surface and interior. In many cases more than one probe may be desired to sample different regions or to work together as a network of sensors. This poster describes a design concept for such a probe under study at Ball Aerospace. The probes are roughly the size of a basketball, allowing for several to be carried by a rendezvous spacecraft and deployed individually. They will survive a freefall to the surface, impacting with a velocity of several meters / second. Deployable panels on the nominally spherical body ensure self-righting to an operational orientation. Each probe accommodates a payload of several kilograms, optimized for its particular investigation. Candidates include imagers, accelerometers, X-Ray spectrometers, sample collection and examination, and possibly pyrotechnic charges for seismic excitation or cratering experiments. The probe provides a standard suite of services such as battery power, data management and communications with the rendezvous spacecraft. We are also studying options for mobility, such as “hopping”, and for anchoring to the surface of a micro-gravity body. Such a basic probe could become a low cost component of future missions that would enable a rich spectrum of in-situ investigations to a large number of target bodies.

Link: Abstract

Link: Ball Aerospace Press Release


"Exploding robots may scout hazardous asteroids"
David Shiga news service
22 January 2007

Now, a group of scientists and engineers have designed a robotic probe small and cheap enough that a fleet of them could be sent to investigate a near-Earth asteroid's composition and structure.

Dennis Ebbets of Ball Aerospace in Boulder, Colorado, US, presented the concept on 7 January at a meeting of the American Astronomical Society in Seattle, Washington, US.

As many as six of the 12-kilogram probes could be loaded on a single spacecraft, which could be launched at relatively low cost to rendezvous with the asteroid.

The main spacecraft would stay a few dozen kilometres away, perhaps nudging the probes towards the asteroid using springs. Once on the surface, the protective spherical shell of each probe would open to allow the probe to scan the surface nearby.

To reduce complexity and costs, the probes lack solar panels and run on battery power, limiting their lifetime to a few days. But each probe could still cover a lot of ground in that time, as they could be fitted with small thrusters to let them hop across the surface.

Eventually the probes could detonate onboard explosives, sacrificing themselves for science one by one. Probes that had not yet detonated would listen for any seismic waves sent rippling out from the explosion, and the main spacecraft could observe the craters left behind. That would tell scientists about the asteroid's strength and internal structure.

If funding can be secured for the probes, they and the host spacecraft could be built in two or three years. The team has identified several near-Earth asteroids that would make good targets, including an asteroid a few dozen metres across called 2003 WP25, which could be reached by 2011.

Link: Article

Video from JPL about Apophis

Interesting video from JPL (Don Yeomans, Paul Chodas) on Apophis.

"Comet/Asteroid Scene Investigation (CSI):JPL scientists use advanced technologies to track asteroids and comets that have the potential to one day come close to Earth."

Link: NASA Video Page

Download options:

(MP4 - 16Mb):
+ Narrated without caption
+ Transcript

(Quicktime - 35Mb):
+ Narrated without caption
+ Narrated with caption

Press Release about 2007 Planetary Defense Conference

"NASA Ames Research Center Director Dr. Simon “Pete” Worden (Brig. Gen., USAF, ret.) will deliver the keynote address on March 5 to open the second Planetary Defense Conference organized by The Aerospace Corporation and co-sponsored by NASA, the European Space Agency, the Planetary Society, and other organizations.

The conference, to be held March 5–8 at George Washington University in Washington, D.C., will feature top scientists and engineers from the international space community. They will be assessing our ability to discover and track near-Earth objects as well as our ability to deflect an asteroid or comet that poses a threat to Earth."

Link: Press Release

29 January 2007

Mission Targets for ESA Don Quijote Asteroid Mitigation Spacecraft

"Earlier this year [2006] the NEO Mission Advisory Panel (NEOMAP), consisting of well-known experts in the field, delivered to ESA a target selection report for Europe's future asteroid mitigation missions, identifying the relevant criteria for selecting a target and picking up two objects that meet most of those criteria. The asteroids' temporary designations are 2002 AT4 and 1989 ML."

From other sources: 1989 ML was considered as target of the Japanese spacecraft Hayabusa (then Muses-C) but had to be given up due to technical reasons...1989 ML ranks 109th among the numbered asteroids and 2002 AT4 ranks 324th among numbered asteroids in terms of Delta-V for spacecraft rendezvous.

Link: Announcement on [By ESA Release, 9/26/2005 1:07:00 PM]

Link: Information from NEODys on 2002 AT4

Link: Information from NEODys on 1989 ML

Link: Delta-v for spacecraft rendezvous with known near-Earth asteroids

2007 Planetary Defense Conference Update

One can view the latest update to the agenda to the 2007 Planetary Defense Conference (March 5-8, 2007 in Washington, D.C. at the Cloyd Heck Marvin Center at George Washington University).

SpaceWorks Engineering, Inc. (SEI) will be presenting two of its papers (one as a main presentation and one as a poster paper). The main paper will be on the multiple mass driver asteroid mitigation concept known as MADMEN (Modular Asteroid Deflection Mission Ejector Node). The other paper will be on prioritization of various mitigation concepts. Note: SpaceWorks Engineering, Inc. (SEI) is also one of the sponsors of the conference.

Link: Website for Conference

Link: Agenda (.pdf)

27 January 2007

Update on ABC Online Poll

Update on the poll from ABC on how prepared the public believes we are for an asteroid strike. Here are the latest results from 27 January 2007 (6:40pm EST). Note: Not a scientific survey

According to some scientists, the prospects for another asteroid or meteoroid hitting Earth of a size similar in magnitude to the one that is believed to have killed the dinosaurs are pretty good.

Do you think the planet is prepared for a severe asteroid or meteor strike?

No. I think we're flying blind and taking our chances on this serious threat.

Maybe. Even if we have some defenses, no one knows whether they will work until they're tested.

Yes. Scientists are working to solve the problem, and humankind will figure out a solution.

Total Vote: 2,666


Article: "Another Asteroid Collision With Earth: It's Just a Matter of Time"
Gina Sunseri
Jan. 24, 2007

Link to Article

25 January 2007

Georgia Tech Undergraduate Teams Designing Apophis Mission

I talked to an aerospace class at the Georgia Institute of Technology in Atlanta yesterday on planetary defense. The class is in the second semester of their capstone undergraduate senior design class focused on a science and tagging mission to Apophis (AE 4803: Senior Space Systems Design II, 2007 - Spring Semester). My presentation is on the class website.

If your are interested in these designs, there will be a semi-public review on February 14, 2006 at Georgia Tech (Location: Room 442 - Design Lab, 40 Guggenheim Building, School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, Georgia - enter from Knight Building, this should last most of the day, contact class instructor Dr. Robert Braun for more information:

Here is the design problem they have been given and to which they have to respond with a conceptual design (related to an Apophis mission).

Design Problem:
In the Spring 2007, each student team will develop a mission and flight system concept to rendezvous, emplace navigation infrastructure and perform a mineralogical assay of the near-Earth asteroid, Apophis. This asteroid is anticipated to fly near the Earth in 2029 and again in 2035. The present mission and flight system design must complete its in-situ investigation prior to the end of calendar year 2016 to allow for implementation of a follow-on mission (either for resource mining or Earth deflection) in one of these two Earth flyby opportunities. The following project constraints apply:

- Rendezvous with Apophis and return all data prior to Dec 31, 2016
- Total lifecycle cost < $500M (FY07$)
- Investigations must be performed in-situ (no Earth-based observation)
- A complete mission & flight system must be proposed (no instrument-only missions)
The NASA Exploration Systems Architecture Study has been implemented as planned and these systems are available for use.

This announcement is open to all types of robotic platforms. The use of advanced technology is encouraged. For all technology not currently spaceflight qualified, a technology development plan must be included.

Link: Class Website

Link: My presentation to the Georgia Tech's AE 4803 Class - Spring 2007 Semester

Link: Georgia Institute of Technology Campus Map

2007 AIAA Student Design Competition on Apophis Assay Mission

The 2007 American Institute of Aeronautics and Astronautics (AIAA) Undergraduate Team Space Design Competition, basically an American design competition resulting in a 50-100 page reports from various teams, will focus on a mineral assay of an asteroid, specifically on Apophis.

"An internet billionaire has offered a prize of $250 million and a share of any profits to the first team that makes a mineral assay of an asteroid, or asteroids. NASA has also agreed to contribute $250 million for the information in the assay if the asteroid chosen is Apophis. Your mission is to design a mission that will fly to Apophis, conduct an assay and scientific characterization of the asteroid, return the information to Earth, and do it for under a total cost of $500 million, including launcher. The mission includes a conceptual design of the spacecraft and payload, selection of a launch vehicle, and description of the mission plan."

Link to AIAA Undergraduate Team Space Design Competition

Link to Request for Proposal (RFP)

Article Along With Online Poll: "Another Asteroid Collision With Earth: It's Just a Matter of Time"

There is a link in this article to an online vote about how prepared people think we are for an asteroid strike. Vote.

Quotes from the article: "He [Apollo 9 astronaut Russell Schweickart and B612 Foundation member] wants to see the United Nations set up an agency mandated to prevent an asteroid from colliding with the Earth and has planned a series of meetings around the world to develop a comprehensive plan. Schweickart anticipates a project that would cost several hundred million dollars, a burden for any single country, but something much more practical as a combined effort...And the lack of a plan, said Schweickart, is something that causes him to lose sleep."

----- Online Poll about Planetary Defense:
Link to Poll:

Results as of 25 Jan 2006 12:16pm EST:

According to some scientists, the prospects for another asteroid or meteoroid hitting Earth of a size similar in magnitude to the one that is believed to have killed the dinosaurs are pretty good.

Do you think the planet is prepared for a severe asteroid or meteor strike?

- No. I think we're flying blind and taking our chances on this serious threat.

- Maybe. Even if we have some defenses, no one knows whether they will work until they're tested.

- Yes. Scientists are working to solve the problem, and humankind will figure out a solution.

Total Votes: 1,572


Article: "Another Asteroid Collision With Earth: It's Just a Matter of Time"
Gina Sunseri
Jan. 24, 2007

Link to Article

21 January 2007

The Planetary Society announces the launch of their Apophis Mission Design Competition"

A month behind this news, but this will be a very important design competition. The subject (transponder type missions) is the first step in any legitimate NEO mitigation process.

"Today at the fall meeting of the American Geophysical Union, The Planetary Society announced the launch of their Apophis Mission Design Competition, which invites participants to submit designs for a mission to rendezvous with and “tag” a potentially dangerous near-Earth asteroid. Tagging may be necessary to track an asteroid accurately enough to determine whether it will impact Earth, and thus help facilitate the decision whether to mount a deflection mission to alter its orbit. The Planetary Society is offering $50,000 in prize money for the competition."

Link: Press Release (13 December 2006)

Link: Apophis Mission Design Competition Rules


I am back from a period of being away from the blog. I have changed the name of the blog from to

There are many interesting events going on this year that will bring needed attention to the subject of planetary defense. I will endeavour to keep up with the latest news this year on the subject of planetary defense.
Note: Any opinions expressed on the blog are solely those of the author. The site is not sponsored by, nor does it represent the opinions of, any organization, corporation, or other entity.