It’s a cosmic dice. This is undoubtedly a major subject asteroid or comet strike can cause great devastation and deeply affect life on earth.
The biggest hit recently was the object that exploded in June 1908 over Tunguska, Siberia, with an energy impact of five to 15 megatons. Then there was that spectacular and devastating air strike in February 2013 over the Russian city of Chelyabinsk. The Chelyabinsk blast caused a shock wave that shattered windows on the ground, and the resulting shards of glass injured more than 1,000 people.
Although these runs are few, those who know them call it wake-up calls.
Infographic: Huge Russian meteoric explosion is the largest since 1908
If you obstruct an incoming object that has the earth in its cross, it means that it must divert or disrupt the dangerous object. It is a task of planetary defense, an ‘applied planetary science’ to address the effects of the impact on the Near Earth (NEO).
Lindley Johnson is NASA’s Planetary Defense Officer and Program Manager of the Planetary Defense Coordination Office. An email from him contains the workline: ‘Hic Servare Diem’, Latin for ‘Here to Save the Day’.
Space.com has caught up with Johnson to discuss recent events and what’s on the planetary defense agenda for the coming year.
Space.com: What is the impact of the December 1 loss of the Arecibo Observatory’s 305 meter telescope on your planetary radar efforts for NEO observations?
Johnson: The National Science Foundation has taken the tough decision that it should be dismissed for safety reasons and that it should be rejected. But the telescope decided to do it on its own. Its planetary radar observation is not unique because we have it at our Goldstone [Solar System Radar in California’s Mojave Desert] also. What was unique about Arecibo was the size of the dish and the power it generated, giving it a longer range than we have at Goldstone.
Space.com: So we have lost ability?
Johnson: We lost that capability, but we did not lose the planetary radar capability. But that makes Goldstone a more critical ability for us than it used to be. We did have some overlap and redundancy before the loss of Arecibo, but now we have Goldstone. I think not only NASA but other agencies will soon be participating in the future for our planetary radar capability. I think the loss of Arecibo will provide the incentive to get it together, a joint effort of several agencies.
Related: Potentially dangerous asteroids (images)
Space.com: How is NASA’s launch next year? Double asteroid conversion test (DART) come along?
Johnson: This is about two-thirds of the way through integration and testing now at the Applied Physics Laboratory [APL, at Johns Hopkins University in Maryland]. It’s starting to look like a real spacecraft. But there were definitely challenges with COVID-19 and delivery through all the parts. One of the remaining big pieces yet to be delivered is the deployment of solar power plants. But the integration schedule has been rearranged. Things look positive throughout the test that is going on. We are quite well able to send DART to Vandenberg [Air Force Base in California] to meet at the end of July launch.
Space.com: Any update from the Italian space agency’s Light Italian Cubesat for Imaging of Asteroid, the LICIACube built to see the impact of DART?
Johnson: They also had their challenges, maybe even more. We hope they will be able to stay on schedule. LICIACube can be integrated with APL, or it can also be integrated with Vandenberg if needed.
Space.com: What do you hope to learn from DART as NASA’s first planetary defense mission?
Johnson: This will confirm to us what the viability of the kinetic impact technique is to divert the orbit of an asteroid and determine that it remains a viable option, at least for smaller asteroids, which is the most common impact hazard.
Space.com: you were engaged in a series of “table top” exercises involving the Federal Emergency Management Agency (FEMA) and other organizations on the nature, risk, and what to do, given an Earth-based encounter with an asteroid or comet impact. What is the value of it for your work?
Johnson: There will definitely be more to come, and possibly next year. We do introduce different scenarios, such as how much time before the impact do you have? Or what is the size of the object? To date, the exercises have been done with a relatively small community. I think in a future exercise, our main goal is to involve a wider community of the NEO Impact Threat Emergency Protocols Working Group, representing a number of other agencies that were not involved in previous exercises. The working group was formed in early 2019 to work on Objective 5 actions in the National NEO Strategy and Action Plan.
Space.com: The JPL Center for NEO Studies is NASA’s center for calculating asteroid and comet orbits and their chance of impacting Earth. Fireball and bullet data are included on their website, some of which are obtained from classified military satellites. How is the data exchange going between NASA and the military?
Johnson: The roads and capabilities are simpler than they used to be. We’re still working on making it faster, more automated. Over the past year, some of it has been somewhat manual, with data being delayed longer than we would like it to be. If you visit the website, you will constantly see the events in our database.
Space.com: Want to get this data much faster?
Johnson: Within hours of the event, if not faster.
Space.com: Asteroid monsters brought back to Earth – whether from Japan’s Hayabusa2 spacecraft and NASAs OSIRIS-REx – How valuable is it to your planetary defense office?
Johnson: It definitely helps us to understand the nature and composition of these objects. Getting these spacecraft there to observe them up close is part of a step-by-step approach, of remote sensing them … and then collecting a sample for laboratory analysis here on earth. This confirms what we think we know about the composition of an asteroid.
This is of course of great importance to the scientific community. But it is also important to understand how mitigation techniques can be more effective. For remote sensing of these objects, you are never sure whether the lines and curves are interpreted correctly. As you get closer, you can confirm a number of things. So this is a kind of bootstrap approach.
Related: The greatest encounter with asteroids of all time!
Space.com: Are there new words on your proposed NASA Near Earth Object Surveyor spacecraft, a space-based infrared telescope that can detect asteroids near Earth?
Johnson: From a technical point of view, everyone agrees that this project is ready to move on to phase B, a preliminary design. The uncertainty is currently what the future budget will be. Our planetary defense program does not have sufficient budget during the number of years it will take to develop NEO Surveyor until now.
Space.com: How do you look at NASA’s planetary defense program to look back and look to the future?
Johnson: The program at NASA continues. Using ground-based capabilities in 2020, it looks like the number of NEOs found will reach 2800 [for the year], a record number for us. Most of them are quite small, much smaller than the 140 meter threshold we are working towards.
The level at which we find the 140 meters and larger asteroids remains fairly stable, about 500 per year. Our projection of the number of objects out there is about 25,000 and so far we have found just over a third, maybe 38% or so. Our models tell us we still have about 15,000 to find. At 500 a year you do math, it’s 30 years we have to go through with these kinds of operations today. We can do it faster. We know we have the technology to do it faster, and that’s what NEO Surveyor is all about.
Leonard David is the author of the book ‘Moon Rush: The New Space Race’, published in May 2019 by National Geographic. David has been reporting on the space industry for over five decades. Follow us on Twitter @Spacedotcom or on Facebook. This version of the story is published on Space.com.