A company I work with recently started design and development for space craft to catch Borisov or Omouamoua, the other extra solar object that recently passed by, using a nuclear decay heat source and Hall effect thrusters. It's pretty realistic and doable - no bleeding edge technologies. Very high power density, very high isp, very fast space craft. Apparently, they can achieve 100km/s + velocity delta for a very small payload: https://www.nasa.gov/directorates/spacetech/niac/2021_Phase_...
The same system could do a Mars visit and return to Earth for small payloads in 50 days.
This stuff needs to get funded! They are funded for initial studies and design with NASA, but I know they are looking for extra funding to pull off the mission faster without being tied to NASA's timelines and mercurial objectives.
The typical radioisotope generator is a Plutonium-238 source like the MMRTG on the Mars rovers. The Plutonium decays by alpha emission with a half life of 80+ years. The problem is there is a very limited supply of Plutonium-238 - we use the entire supply for Mars Rover - and it's very controlled material.
The CAB starts with a non-radioactive material like Cobalt-59 spheres placed in a ceramic matrix. It is then put into a nuclear reactor where it turns into Cobalt-60, which releases energy by beta and gamma emission with a half life of 5 years. This charging can be done every couple years to generate more Cobalt-60 inside the device. Such a power source is something like 40x as power dense as the Pu-238 source and since it's made of high temperature ceramics, it can go to very high temperatures which is very useful for space generators where you have to reject heat using blackbody radiators.
Thanks, so "charging" means activating stable cobalt to radioactive cobalt by neutron capture. This sounds very doable and is in line with what I expected for a project selected for the program.
I asked because of an experiment conducted by a german research institute at an accelerator in France. They modified nuclear states by using "shaped" x-ray pulses. I wondered if it were possible to store energy by making a nucleus undergo a transition to a meta-stable state (spontaneous emission is forbidden by a selection rule) but which could eventually be triggered by another pulse to extract energy again.
I hope my description of the process I imagine is not too far off, it has been a while since my nuclear physics course ;)
if it's what i think they are, they are essentially batteries with a radioactive source. It relies on the gradual decay of the source to create energy which is somehow harnessed and used as a power source. I have learnt here on HN that they last many years, are used on space projects such as the voyager probes, and more recently, the mars rover. They are impractical for other uses, such as powering your fridge and home. And their price is.... astronomical.
One thing that comes to mind is Hafnium 178m2, but (for understandable reasons) there's basically zero public information about the feasibility of charging and induced discharging of any nuclear isomer, let alone one so energy dense.
I wonder, has anyone seriously considered employing the Oberth effect as close to the Sun as possible? Combined with using solar power for propulsion energy, that could get interesting.
I could swear I have seen a video on building a test chamber with an intense light source to test a heat shield similar to the parker solar probe but with hydrogen or helium piped through it for a solar thermal thruster. But I can't find it now.
I appreciate the coolness factor. But, unless the payload can be enough to pull off a 1998 Bruce Willis, what's the immediate benefit? Or, would this be fundamental to some research?
Regarding Omouamoua, we just observed for the first time in human history, a cylinder or plate shaped object from another star flying through our solar system with questionable orbital velocities (we are not quite sure how to explain a small acceleration it had). A cylinder/plate is not a low energy geometry (things like to turn into spherical type objects over time), it's from another solar system, we don't know very much about it. How could you not want to visit it?
It's an opportunity to pull off a speed and distance record, visit something from another solar system, resolve big research questions about its shape, composition, origin and rule out any theories of its possible intelligent origin. They are also pursuing it to showcase the benefits of nuclear heat for space.
This is a more of an etymology issue than what you think, if you need to look up the word etymology, I'm referring to the the history of the words and not suggesting any changing meaning
Search for evidence of life outside the solar system. Unless you're planning a trip to another star system this is all we've got in our lifetimes.
Hitching a fast ride to the outer edges of the solar system since it's on a hyperbolic trajectory.
What is the asteroid made of? That shape of asteroid is not normal. Usually they're rubble piles, these were different. Is there formation methods we don't yet know? Were they fragments of a planet's destruction?
On an engineering level, we've never had to rendezvous with something on this trajectory before. Can we?
That is how progress works. Lots of things were researched or invented before progress in other areas (materials, economics, society, other scientific finds...) made these findings useful or even feasible. You never know when and why you will need this, the only thing you know - it will be used eventually. Maybe this will give some important clues into the future interstellar travel, maybe the tricks and technologies invented for this mission will be used elsewhere, maybe sample will give important clues into the origins and probability of life.
People often claim commerce and free markets are the driver of innovation. That's true, but they're not the only driver. Industry and national "moonshots" play off each other very well.
I think the article title is not representing the actual finding well. Stated better in this article: https://earthsky.org/space/2i-borisov-pristine-comet-interst..., "2I/Borisov could represent the first truly pristine comet ever observed," meaning it hasn't interacted with a star before.
The headline seems to be plainly wrong. It's an interstellar comet that supposedly has not had a close encounter with another star. But it certainly is not the "first interstellar comet to have visited our solar system", or did I miss something?
It is the first confirmed interstellar comet and so is the first under the interstellar comet classification, Unfortunate that the headline does not contain that detail however.
That was my reaction; I'm not sure whether they meant to say the "21/Borisov, the interstellar comet for whom our system is the first solar system it has visited", or (as other comments suggest) "the first confirmed interstellar comment to visit our system". Obviously if something is only now noticed with modern technology, it's unlikely that interstellar comets haven't swung by our solar system many times before. We just don't have a record of it.
It's somewhat debatable. 1I/Omuamua was reclassified as an asteroid because it didn't exhibit a coma. But it's possible that it's a remnant of a comet.
Despite reading quite a lot about astronomy, comets and asteroids and the history of all of the three, I didn't get the distinction between asteroids and comets yet. I understand the composition makes the difference, but I didn't get why we expect exactly two (!) distinct categories of intersolar/interstellar objects, and giving them exactly two distinct names. Why not more, or less (i.e. no distinction at all, just a summary of the probable composition)?
Why is this so? Is there a fundamental reason to make this special distinction, or is it just "tradition"?
Asteroids mostly have circular orbits. Comets (at least the ones we see) tend to have very highly eliptical orbits. That I think is the origin of the distinction.
But asteroids also tend to be at lower distances from the sun than comets. That in turn leads to them tending to be composed more of rocky material, whereas comets have more ice.
I am not an astronomer, so any and all details may be in error. Corrections are welcome.
Mostly tradition. Asteroids have had their volatiles baked off their surface, or never had them due to forming inside the frost line. But it’s not a very intrinsically meaningful distinction—it’s more about what they look like from the vantage point of Earth as they come by on close approach.
Isn't it rather odd that this object is said to (a) be from outside the solar system; and (b) be made from the orginal material the solar system formed from?
I presume the object is thought to be from the Oort Cloud, much of which is arguably "interstellar space"; but comets cannot form in interstallar space; there's nothing there to form from. Comets form from the protoplanetary disk, making them part of the stellar system that disk turns into.
It's possible, I guess, for a comet to hurled out of one star system, and become adopted by another; but the article doesn't claim that's what happened here. This is just a comet that doesn't seem to have visited close to the Sun before. Most Oort Cloud objects have never been near the Sun.
It irritates me to read claims like this. Our solar system is billions of years old. How could we possibly know if 2I/Borisov is the very, very absolute first interstellar comet to have visited our solar system?
The same system could do a Mars visit and return to Earth for small payloads in 50 days.
This stuff needs to get funded! They are funded for initial studies and design with NASA, but I know they are looking for extra funding to pull off the mission faster without being tied to NASA's timelines and mercurial objectives.