Near-Earth Object (NEO) Surveillance Mission

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After years of study and failed proposals, NASA has decided to proceed with development of a space-based telescope to search for near-Earth asteroids.
Thomas Zurbuchen, NASA’s associate administrator for science, said Sept. 23 the agency will go forward with a mission called the Near-Earth Object (NEO) Surveillance Mission, a concept based on the NEOCam mission that was a finalist in the previous competition for Discovery-class planetary science missions.

https://spacenews.com/nasa-to-develop-mission-to-search-for-near-earth-asteroids/

 

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Work Is Under Way on NASA’s Next-Generation Asteroid Hunter [Aug 28]

The mirrors for NASA’s Near-Earth Object Surveyor space telescope are being installed and aligned, and work on other spacecraft components is accelerating.

NASA’s new asteroid-hunting spacecraft is taking shape at NASA’s Jet Propulsion Laboratory in Southern California. Called NEO Surveyor (Near-Earth Object Surveyor), this cutting-edge infrared space telescope will seek out the hardest-to-find asteroids and comets that might pose a hazard to our planet. In fact, it is the agency’s first space telescope designed specifically for planetary defense.

Targeting launch in late 2027, the spacecraft will travel a million miles to a region of gravitational stability — called the L1 Lagrange point — between Earth and the Sun. From there, its large sunshade will block the glare and heat of sunlight, allowing the mission to discover and track near-Earth objects as they approach Earth from the direction of the Sun, which is difficult for other observatories to do. The space telescope also may reveal asteroids called Earth Trojans, which lead and trail our planet’s orbit and are difficult to see from the ground or from Earth orbit.

NEO Surveyor relies on cutting-edge detectors that observe two bands of infrared light, which is invisible to the human eye. Near-Earth objects, no matter how dark, glow brightly in infrared as the Sun heats them. Because of this, the telescope will be able to find dark asteroids and comets, which don’t reflect much visible light. It also will measure those objects, a challenging task for visible-light telescopes that have a hard time distinguishing between small, highly reflective objects and large, dark ones.

“NEO Surveyor is optimized to help us to do one specific thing: enable humanity to find the most hazardous asteroids and comets far enough in advance so we can do something about them,” said Amy Mainzer, survey director for NEO Surveyor and a professor at the University of California, Los Angeles. “We aim to build a spacecraft that can find, track, and characterize the objects with the greatest chance of hitting Earth. In the process, we will learn a lot about their origins and evolution.”

Coming Into Focus
The spacecraft’s only instrument is its telescope. About the size of a washer-and-dryer set, the telescope’s blocky aluminum body, called the optical bench, was built in a JPL clean room. Known as a three-mirror anastigmat telescope, it will rely on curved mirrors to focus light onto its infrared detectors in such a way that minimizes optical aberrations.

“We have been carefully managing the fabrication of the spacecraft’s telescope mirrors, all of which were received in the JPL clean room by July,” said Brian Monacelli, principal optical engineer at JPL. “Its mirrors were shaped and polished from solid aluminum using a diamond-turning machine. Each exceeds the mission’s performance requirements.”

Monacelli inspected the mirror surfaces for debris and damage, then JPL’s team of optomechanical technicians and engineers attached the mirrors to the telescope’s optical bench in August. Next, they will measure the telescope’s performance and align its mirrors.

Complementing the mirror assembly are the telescope’s mercury-cadmium-telluride detectors, which are similar to the detectors used by NASA’s recently retired NEOWISE (short for Near-Earth Object Wide-field Infrared Survey Explorer) mission. An advantage of these detectors is that they don’t necessarily require cryogenic coolers or cryogens to lower their operational temperatures in order to detect infrared wavelengths. Cryocoolers and cryogens can limit the lifespan of a spacecraft. NEO Surveyor will instead keep its cool by using its large sunshade to block sunlight from heating the telescope and by occupying an orbit beyond that of the Moon, minimizing heating from Earth.

The telescope will eventually be installed inside the spacecraft’s instrument enclosure, which is being assembled in JPL’s historic High Bay 1 clean room where NASA missions such as Voyager, Cassini, and Perseverance were constructed. Fabricated from dark composite material that allows heat to escape, the enclosure will help keep the telescope cool and prevent its own heat from obscuring observations.

Once it is completed in coming weeks, the enclosure will be tested to make sure it can withstand the rigors of space exploration. Then it will be mounted on the back of the sunshade and atop the electronic systems that will power and control the spacecraft.

“The entire team has been working hard for a long time to get to this point, and we are excited to see the hardware coming together with contributions from our institutional and industrial collaborators from across the country,” said Tom Hoffman, NEO Surveyor’s project manager at JPL. “From the panels and cables for the instrument enclosure to the detectors and mirrors for the telescope — as well as components to build the spacecraft — hardware is being fabricated, delivered, and assembled to build this incredible observatory.”

Major Component of NASA’s NEO Surveyor Begins Test for Deep Space [Jan 22]

A major element of NASA’s Near-Earth Object (NEO) Surveyor is undergoing testing at the agency’s Johnson Space Center in Houston. Called the instrument enclosure, the angular structure measures 12 feet (3.7 meters) long and is designed to protect the spacecraft’s infrared telescope while also removing heat from it during operations in space.

After being built at NASA’s Jet Propulsion Laboratory in Southern California, the enclosure was shipped to NASA Johnson in November. The NEO Surveyor mission is targeting a late 2027-launch.

As NASA’s first space-based detection mission specifically designed for planetary defense, NEO Surveyor will seek out, measure, and characterize the hardest-to-find asteroids and comets that might pose a hazard to Earth. While these near-Earth objects don’t reflect much visible light, they glow brightly in infrared light due to heating by the Sun.

But first, the mission needs to perform a series of tests on all the equipment to make sure it survives launch and performs as intended in the vacuum of space. To that end, a crew at NASA Johnson, led by NEO Surveyor contractor BAE Systems, has been exposing the enclosure to the frigid, airless conditions it will experience in deep space using the facility’s historic Chamber A. Part of Johnson’s Space Environment Simulation Laboratory, the cavernous thermal-vacuum facility tested the Apollo spacecraft that traveled to the Moon and, more recently, NASA’s James Webb Space Telescope’s optical element and science instruments in 2017.

After testing, the enclosure will travel to the Space Dynamics Laboratory (SDL) in Logan, Utah. There, it will be joined together with the telescope’s blocky aluminum body, called the optical bench, which JPL built and is currently testing.

 

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https://twitter.com/x/status/2052178296159535415

View: https://twitter.com/NASASolarSystem/status/2052178296159535415

NASA's latest eye on the sky is coming together!

The Near-Earth Object (NEO) Surveyor — NASA’s first infrared space telescope purposely designed to discover potentially hazardous asteroids and comets — is undergoing integration and testing.

By identifying objects that ground telescopes can miss, this mission will provide the critical data we need to safeguard our planet for years to come. It's all about finding asteroids before they find us!

 

[Scott Kenny]

Silly question:

Why is this a NASA mission instead of a DOD mission? Just because the "enemy" is a big dumb rock?

 

[Byeman]

Silly question:

Why is this a NASA mission instead of a DOD mission? Just because the "enemy" is a big dumb rock?

That has been an issue. Congress has a little to do with it.

 

[blackstar]

Silly question:

Why is this a NASA mission instead of a DOD mission? Just because the "enemy" is a big dumb rock?

Back in the 1990s, some DoD ground telescopes were spotting NEOs. However, Congress wrote it into law that this was a NASA mission. NASA officials did not really want to do it, in part because NASA did not operate ground-based telescopes and did not want to be on the hook paying for them. However, NASA did end up paying to conduct the Catalina Sky Survey using a telescope in Arizona and one in Australia. (These were existing telescopes.)

In 2005, Congress wrote language into a bill that required NASA to detect 90% of NEOs 140 meters or larger by 2020. But the White House at that time did not want to pursue that mission and did not ask for money to fund it, and Congress did not add money into NASA's budget at that time to fund it.

In 2009 I was the study director on a congressionally-mandated study to look into the issue. We determined that given the existing expenditures on searching for NEOs, NASA was not going to achieve the 2020 goal. However, we identified several possible things that the agency could do, if they were given more money. (Note that we did not recommend that they get more money or that they be given these missions, it was written along the lines of "If you want to do these things, this is what it will cost...")

One of the possible things to do, and the only one that would realistically reach that 90% NEO goal within a reasonable amount of time (about a decade) was a space-based infrared telescope. NASA funded some technology development work in the 2011+ time period to develop the sensors for that telescope.

As a result of our 2009 study (delivered in early 2010), the Obama administration increased funding for NASA to detect NEOs. However, the administration did not approve the development of a space-based IR telescope to accomplish the mission.

In 2019, we were asked by NASA to conduct another study on whether a space-based visible light or infrared telescope was better suited for NEO detection. We determined that infrared is much better for the task. Around 2020 or 2021, NASA formally started development of the NEO Surveyor mission, although they dragged their feet a bit for reasons I don't understand. Also, in the meantime several other ground-based telescopes have become active, including the Vera Rubin telescope, and they are increasing the number of NEOs detected.

That's the basic policy history, leaving lots of things out. But to answer your question another way, DoD doesn't want this mission. They don't think it's their responsibility, just like they are not responsible for tracking hurricanes.

 

[Scott Kenny]

[...]

That's the basic policy history, leaving lots of things out. But to answer your question another way, DoD doesn't want this mission. They don't think it's their responsibility, just like they are not responsible for tracking hurricanes.

Thank you!

I still think that detecting and tracking an existential threat should be a military mission not a NASA one, but now I know why it's not.

 

[blackstar]

Thank you!

I still think that detecting and tracking an existential threat should be a military mission not a NASA one, but now I know why it's not.

Just to add a bit more to what I wrote above, in the 1990s, the DoD had ground telescopes for tracking objects in Earth orbit. Those telescopes were also detecting NEOs. But I think that for awhile there was no coordinated effort to track NEOs. DoD was not doing it. Congress designated NASA as responsible and NASA at least initially used the DoD data, and then over time, Congress directed NASA to actually operate its own equipment to do the detection and tracking.

There were a few people in DoD who thought that it should be a DoD mission, but they tended to be enthusiastic junior officers who were ignored by colonels and generals who had more realistic threats to worry about. I don't think there has ever been any DoD support for this mission at a high level.

I should also add what I touched on in my above post that NASA did not want this mission either. The threat of a major impact is very low. There are lots of people who have looked at the risk and said that this is not a good subject to spend money on. And NASA particularly hates it when they are mandated to do a mission but no extra money is provided to do that mission. That means that they have to carve the money out of things they consider more important.

There is an argument for this being a NASA mission, which is that understanding the composition of potentially hazardous asteroids is an important component of deflecting them. There is a science aspect to this mission, although not a big one. Mostly it is detecting and tracking, not science. But NASA is the proper agency to support the science.

One last thing I'll add is that whenever the public is surveyed about what they think NASA should be doing, detecting and tracking NEOs is usually at the top of the list. But in terms of dollars spent, it is actually a low priority mission for NASA. I don't think it should be higher, I'm just noting that the public believes it is very important.

 

[blackstar]

Because I'm bored and have some time, I'll add a bit more:

It has long been common for people to think that the biggest risk is the big asteroids that can wipe out the planet, like the one that did in the dinosaurs. These are generally 1 kilometer or bigger. The reality is that almost all of these have been detected and tracked and are not going to hit the Earth. Simply put, the bigger it is, the easier it is to see, so most of those were detected early on. There may be a few more out there, but they will eventually be found and it is very unlikely that they have trajectories that hit Earth.

The bigger risk is actually the medium-size ones that can do city or state-wide damage, but are much harder to find. The people who search for these things set a somewhat arbitrary limit of 140-meters in diameter or larger. That does not mean that a 100-meter diameter NEO is not dangerous, just that you have to set a limit and start looking. The 2005 legislation established a requirement to detect 90% of these by 2020. I don't know the current percentage, but it is probably about 35% of them detected, so there is still a long way to go to get to 90%. (And in case you are wondering how it is possible to know what percentage you have detected without knowing the total population size, it has to do with the detection rate. That drops as you detect more, and you can determine when you have detected most of them because it gets harder to find new undetected ones.)

Using ground-based telescopes alone, it is really difficult to reach the goal. It takes a long time to get to 90%. The second study that I ran, in 2019, plotted those things out and they determined that it just was not realistic to expect ground based telescopes to get to the 90% level. A space-based infrared telescope is the only realistic option, but it is expensive.

I think that the NEO Surveyor mission will get to the 90% goal in about 7-8 years of operations. But, it will also gather a lot of other information along the way, and that will produce a much better understanding of how many NEOs are out there and what they are doing. It will, for instance, detect a lot of NEOs smaller than 140 meters in diameter, which will help us understand the other population sizes. As somebody explained it to me, NEO Surveyor might provide enough information to determine that this is not something we need to worry about at all.

(Yes, there are long-period comets that could impact Earth. There's not much you can do about that.)