At today's SBAG meeting it was noted that the Dimorphos impact will be at 7:14 PM EST on September 26.
added to my calendar
Google probably isn't sure what to make of the location "asteroid Dimorphos"
At today's SBAG meeting it was noted that the Dimorphos impact will be at 7:14 PM EST on September 26.
In late September Daylight Savings Time will be in effect.
How was it specified at the SBAG?
Will the impact be 7:14 PM EST or EDT?
Why does one star look elongated? Is it in motion? A planet?
Why does one star look elongated? Is it in motion? A planet?
It could be a cosmic ray.
Dart and Didymos trajectories plotted as per NASA Horizons data.
Unfortunately I am not able to get the relative distance as I can't get Didymos as the central body; in case anybody wants to give it a try:
Dart: -135
Didymos: DES=2065803
I used these urls and manually overlayed the results:
Dart urlDidymos url
I also found
a guide to NAIF SPICE system about asteroids and their moons, with a specific example about Didymos (last lines):
Asteroids
According to the original schema, NAIF ID codes for permanently numbered asteroids registered in the JPL Solar System Dynamics (SSD) Group database are 7-digit numbers determined using the algorithm
NAIF ID code = 2000000 + Permanent Asteroid Number
limited to the 2000001 to 2999999 range and allowing up to 1 million asteroids.
For newly discovered asteroids with provisional numbers SSD internally uses 7-digit numbers determined via the algorithm
NAIF ID code = 3000000 + Provisional Asteroid Number
limited to the 3000001 to 3999999 range and also allowing up to 1 million asteroids.
Given the need to accommodate many more asteroids expected to be discovered by surveys coming on-line in the near future and the desire to encode in the NAIF ID codes the roles of individual asteroids and barycenters in binary and multi-body asteroid systems in a way similar to planetary systems, in 2019 SSD and NAIF agreed to extend the original schema.
Under the extended schema all permanently numbered singular asteroids have 8-digit NAIF ID codes with the original 7-digit IDs still allowed to be used. Such asteroids are assigned NAIF ID codes using the algorithm
NAIF ID code = 20000000 + Permanent Asteroid Number
limited to the 20000001 to 49999999 range and allowing up to 30 million asteroids.
For asteroid systems with two or more bodies the 8-digit NAIF ID code represents the barycenter. Individual satellites have a prepended number 1 through 8, while the primary body uses the ``last available'' prefix 9, resulting in 9-digit NAIF ID codes. This is analogous to the planetary system approach except a single extra number is added as a prefix rather than two numbers added as a suffix. In the case of ID codes presented by strings, a 0 prefix could be added to the ID of the barycenter, if printing out uniform 9 digits is desired.
For newly discovered singular asteroids and asteroid system barycenters with provisional numbers NAIF ID codes are also 8-digit numbers determined via the algorithm:
NAIF ID code = 50000000 + Provisional Asteroid Number
limited to the 50000001 to 99999999 range and allowing up to 50 million asteroids, with the same prefix rule used to derive the 9-digit IDs for the primary and satellite bodies in multi-body systems.
For example, asteroid Yeomans (2956) has NAIF ID number 2002956 according to the original schema and NAIF ID number 20002956 according to the extended schema, while asteroids Didymos (65803) and its satellite Dimorphos can be accommodated only using the extended schema with IDs 920065803 and 120065803, and Didymos system barycenter with ID 20065803.
NAIF ID NAME
________ ____________________
20065803 'DIDYMOS_BARYCENTER'
120065803 'DIMORPHOS'
920065803 'DIDYMOS'
These info should be useful to figure out how to track Didymos, Didymoon and DART using one of the pages below, but I didn't succeed yet (I cant find the right kernels):
https://wgc.jpl.nasa.gov:8443/webgeocalc/#StateVectorhttps://wgc2.jpl.nasa.gov:8443/webgeocalc/example/perform-calculation.htmlhttps://ssd.jpl.nasa.gov/horizons/app.html#/
Found the
right parameters to plot Dart vs Didymos: "center" must be "@20065803" rather than "@2065803" (one zero added, don't know why).
Closest approach is currently.... the impact (planned at 26-Sep-2022 23:14:18.1108 UTC), but trajectory continues afterwards.
No luck in tracking Dymorphos (120065803) vs Didymos yet.
Very cool updated on Horizons system just yesterday, March 3rd!
Horizons On-Line System News
March 3, 2022
-- The 65803 Didymos system, containing the DART mission's satellite impact
target (Dimorphos), has been elaborated and can be accessed under the
following ID codes:
Didymos system barycenter : 20065803
Primary body (Didymos) center: 920065803
Secondary (Dimorphos) center : 120065803
Thus one can generate ephemerides such as ...
target center
Dimorphos wrt DART: 120065803 @ dart (or "@-175")
Dimorphos wrt Didymos primary: 120065803 @ 920065803
Dimorphos wrt Didymos bary : 120065803 @ 20065803
... and so on.
A mass model for the system and rotation model for Dimorphos are also
defined to generate orbital elements and cartographic data.
However, DART will be using optical navigation and maneuvering to
refine the trajectory to impact, so this prediction-based model is
only a nominal guide.
https://ssd.jpl.nasa.gov/horizons/news.htmlThis allows plotting the current typical orbit of Dymorphos around Didymos, to compare it to new orbit after impact:
http://win98.altervista.org/space/exploration/3d/space-explorer-tracker.html?orbiter=120065803¢er=@20065803&start=2022-MAR-04&stop=2022-03-05&step=1m
.@NASA's #DARTMission is set to deflect an asteroid soon, but #PlanetaryDefense is a global effort - 150 international scientists are meeting to prepare for @ESA's #HeraMission, which will examine the deflected mass & determine if humans can indeed divert threatening asteroids.
https://twitter.com/AschbacherJosef/status/1531199271239819266
Given the
recent findings about Bennu, I think that we have to rethink from scratch any "asteroid redirection mission": shooting a small asteroid would probably "deviate" it as much as shooting a cloud deviates it.
And if the asteroid is massive enough to be compact enough not to "absorb" the bullet, it won't be probably affected anyway by the impact due to huge mass difference.
And Dimorphos/Didimoon is 3 times smaller than Bennu, 50-100m: possibly the 650 kg bullet will pass through it, or will "disassemble" it!
It will be a great show.
Given the recent findings about Bennu, I think that we have to rethink from scratch any "asteroid redirection mission": shooting a small asteroid would probably "deviate" it as much as shooting a cloud deviates it. And if the asteroid is massive enough to be compact enough not to "absorb" the bullet, it won't be probably affected anyway by the impact due to huge mass difference.
And Dimorphos/Didimoon is 3 times smaller than Bennu, 50-100m: possibly the 650 kg bullet will pass through it, or will "disassemble" it!
It will be a great show.
For small low density asteroids. Think a high surface area impactor might work for "asteroid redirection". Essentially deploying a solar sail like structure as impactor.
Hopefully DART will not have a no show by passing through Didimoon with nothing to see. Of course DART might survive a fly through scenario enough to be detectable afterwards.
Given the recent findings about Bennu, I think that we have to rethink from scratch any "asteroid redirection mission": shooting a small asteroid would probably "deviate" it as much as shooting a cloud deviates it. And if the asteroid is massive enough to be compact enough not to "absorb" the bullet, it won't be probably affected anyway by the impact due to huge mass difference.
And Dimorphos/Didimoon is 3 times smaller than Bennu, 50-100m: possibly the 650 kg bullet will pass through it, or will "disassemble" it!
It will be a great show.
For small low density asteroids. Think a high surface area impactor might work for "asteroid redirection". Essentially deploying a solar sail like structure as impactor.
Hopefully DART will not have a no show by passing through Didimoon with nothing to see. Of course DART might survive a fly through scenario enough to be detectable afterwards.
No ship that far out is detectable on its own. We can only see the radio transmissions from it.
Given the recent findings about Bennu, I think that we have to rethink from scratch any "asteroid redirection mission": shooting a small asteroid would probably "deviate" it as much as shooting a cloud deviates it. And if the asteroid is massive enough to be compact enough not to "absorb" the bullet, it won't be probably affected anyway by the impact due to huge mass difference.
And Dimorphos/Didimoon is 3 times smaller than Bennu, 50-100m: possibly the 650 kg bullet will pass through it, or will "disassemble" it!
It will be a great show.
There is no way DART will pass through it, or will "disassemble" - not even if Dimorphos is only a heap of dust.
The lowest constraint for the density of Dimorphos is 1150 kg m^−3.
see Rivkin, Andrew & Chabot, Nancy & Stickle, Angela & Thomas, Cristina & Richardson, Derek & Barnouin, Olivier & Fahnestock, Eugene & Ernst, Carolyn & Cheng, Andrew & Chesley, Steven & Naidu, Shantanu & Statler, Thomas & Barbee, Brent & Agrusa, Harrison & Moskovitz, Nicholas & Daly, Ronald & Pravec, Petr & Scheirich, Peter & Dotto, Elisabetta & Hirabayashi, Masatoshi. (2021). The Double Asteroid Redirection Test (DART): Planetary Defense Investigations and Requirements. The Planetary Science Journal. 2. 173. 10.3847/PSJ/ac063e.
Given the recent findings about Bennu, I think that we have to rethink from scratch any "asteroid redirection mission": shooting a small asteroid would probably "deviate" it as much as shooting a cloud deviates it. And if the asteroid is massive enough to be compact enough not to "absorb" the bullet, it won't be probably affected anyway by the impact due to huge mass difference.
And Dimorphos/Didimoon is 3 times smaller than Bennu, 50-100m: possibly the 650 kg bullet will pass through it, or will "disassemble" it!
It will be a great show.
For small low density asteroids. Think a high surface area impactor might work for "asteroid redirection". Essentially deploying a solar sail like structure as impactor.
Hopefully DART will not have a no show by passing through Didimoon with nothing to see. Of course DART might survive a fly through scenario enough to be detectable afterwards.
No ship that far out is detectable on its own. We can only see the radio transmissions from it.
It's a pity that HERA is so late that it will be only be able to see the remains; original mission was to have HERA looking while DART impacting.
Is LICIACube "observer" still part of the mission?
Looking for info on LICIACube (found nothing
) I found this interesting, very recent paper.
Global-scale Reshaping and Resurfacing of Asteroids by Small-scale Impacts, with Applications to the DART and Hera MissionsSabina D. Raducan, Martin Jutzi
Summary:
We predict that the DART impact is likely to produce morphologies that are dissimilar to cratering and change the global morphology of the asteroid. In such cases, Hera will not find a classical crater morphology.
[...] We find that for the current energy of the DART impact, the catastrophic disruption of the target is not possible. However, the DART impact may probe not only the surface but also the interior of the asteroid.
So maybe the asteroid will not be destroyed, but very likely "something more" than just a crater will be caused.
I can't find any official source about canceling of 2001 CB21 flyby planned for 3-6 march 2022, apart from one line in
this page.
Why was it canceled? It was needed for camera calibration!
Instead, I found a
paper which assures that the DART mission will not cause Didymos impacting on Earth due to the deviation...
Interstingly, paper was published after launch.
I can't find any official source about canceling of 2001 CB21 flyby planned for 3-6 march 2022, apart from one line in this page.
Why was it canceled? It was needed for camera calibration!
Instead, I found a paper which assures that the DART mission will not cause Didymos impacting on Earth due to the deviation...
Interstingly, paper was published after launch.
There already had been studies showing that there was zero risk of earth impact before the asteroid was selected. It was kind of a requirement.
There already had been studies showing that there was zero risk of earth impact before the asteroid was selected. It was kind of a requirement.
I think you didn't get the point: I am talking about what will happen to the binary system
after the impact; it's weird they calculated it only after launching the mission, and it's creepy that only 2 months from the impact they figured out that the impact will have way different effect w.r.t what they supposed at the time of mission designing (it won't be a redirection, it will be an explosion).
As far as I can understand, the binary system will be turned into a huge debris cloud, with a lot of material leaving the original system orbit at escape velocity, something similar to what happens when an Earth-orbiting satellite is intentionally destroyed by an impact, but at "km scale".
I also understood that they are currently working at a graphical simulation of such a cloud debris and its evolution... then I got lost on details.
And if the asteroid is massive enough to be compact enough not to "absorb" the bullet, it won't be probably affected anyway by the impact due to huge mass difference.