I couldn’t last 30 seconds.
Bad news: I am not an astronaut flying past the Moon.
Good news: I don’t have to talk to Trump.
Mmmm it evens out may be…
I never cease to be amazed at how mind-bogglingly, ineffably stupid Trump is. That must be the most inane conversation anybody ever had with astronauts.
Back on topic, Orion is less than 192,800 miles from earth and now going 1,965 mph. The indicated velocity and distance from earth are now probably quite accurate. The distance from the moon is a bit misleading – it’s growing much more rapidly than the rate at which distance to earth is decreasing, namely because a component of the growing distance is the moon itself moving away in its orbit.
I was honestly wondering when they would connect him to the spaceship, and how they might react. One wonders what the debriefing may be like.
The dials on the live feeds really need to be altered to say “Distance To Earth” and “Distance From Moon.” As of right now, they’re about 1/3 of the way back.
There was a brief interruption where the CNN live update wasn’t updating, but now it is again. 2,411 mph and 166,252 miles from earth. Not accelerating as fast as I would have expected, but still a long way to go! There’s a scheduled mid-course correction late this afternoon EDT.
ETA: A different tracker is indicating its speed as 10,393 km/h which is 6,458 mph which seems more plausible at this point.
The other tracker appears to keep changing its mind about speed and distance from earth. The tracker that CNN uses, while sometimes not updating, is at least consistent. Right now it’s showing just under 2,500 mph, a little over 162,000 miles from earth.
At 4,250 mph and about 88,000 miles from earth, the astronauts are in their last sleep period before splashdown in the Pacific tomorrow!
I’m with you on the unlikelihood of seeing meteor impacts. Without an atmosphere, these would have to be some big rocks slamming into the far side. I know people were really stunned at how much more cratering there was on the far side when it was first seen.
How much the moon protects the earth by taking meteroid hits isn’t really known. How much science or even cool pictures this mission accomplished is yet to be seen. If it were a publicity tour for human spaceflight, NASA, and how great the moon is, mission accomplished. Well, “when touchdown brings them down” and once again we get told over and over how they’ll be out of radio contact for re-entry.
I was thinking about the likelihood of meteorite impacts and while I am no planetary scientist, is it really that surprising they spotted some?
Get three people to sit in a garden looking up at the sky for the entire night, and even though they might be seeing only a fraction of the sky someone will probably spot a shooting star (i.e. a meteor). These astronauts were looking at an entire half of the moon for a long period of time. The moon has a relatively uniform colour and albedo and they’ve been trained to specifically look for impacts. The astronauts even stated that they were sure they had not misattributed the sightings.
I heard an interview with NASA’s chief science officer saying that watching for impacts was one of their top science objectives but she had privately thought it was unlikely, so was truly delighted to hear they had seen at least four.
We’ve discussed this here before. Like any FQ conversation, how learnedly we did so is an open question. The consensus is the Moon does squat-all to “protect” the Earth from meteor impacts.
It represents a negligible fraction of the surface area of the sphere from which meteors approach the Earth-Moon system. Even if we confine ourselves to a narrow equatorial slice within e.g.10 degrees of the Earth orbital plane, the Moon is still obscuring only a tiny fraction of the avenues of approach.
As to gravitational perturbations rather than direct impacts, the math suggests the Moon’s presence is equally likely to convert a miss into a hit or a hit into a miss. Net result: zero.
The same is true in the other direction: the Earth doesn’t materially protect the Moon from incoming meteors.
What kind of radiation damage is an astronaut looking at after this type of lunar mission?
Or, in other words, the number seen was surprising to the NASA scientist, too.
I plan to be glued to the TV (well, NASA’s youtube stream) tonight when the reentry happens, It’s the riskiest part of the mission, specially with the Integrity’s defective heat shield.
Here’s a good Reddit thread on that
Thanks! For Artemis 1 “Total mission dose equivalents were 26.7–35.4 mSv, with between 1.80 and 3.94 mSv attributable to the belt passes.”
…
35 mSv is equivalents of three full body CT-scans. It is equal to the recommended 5-years exposure limit for workers. And it is one tenth the dose received by relocated Chernobyl residents. It’s also 15 times what normal people are exposed to every single years in the normal environment.
It was likely enough to be one of the very top science objectives though!
That’s some of the science I expect they’ll bring back. I assume the outside of the capsule beyond any protection would measure something similar to a spacewalk or being on the moon in the sun.
The spacecraft would have superior shielding to the Apollo capsules. So, outside of any major solar activity. Radiation at these levels is measured in millisieverts (mSv). I know flying in an airplane is often compared to dental scans, yet fhey (and even those in the ISS) are inside the protective Van Allen Belts.
In this case 10 mSv is about one CT scan. For a 10 day trip tjey might expect about ~20-30 mSv with the added condition that for any major solar activity, now we have warnings in advance and special shelters they might go to. I dunno what this capsule has, yet I imagine measured in phone booths it’s about 2, yet in general this capsule should be better shielded than Apollo (capsule). Surely they have the kind of tags dental and X-ray technicians have so that’s something to find out.
Comparatively, it would take several hundred cSv’s to have even short term radiation sickness so they’re well within that range. Stay on the Moon for 10 days, avoid any major solar activity predicted in a shelter, and you’ll likely be around there (again the suits made for landing on the moon shouldt be better protected).
tldr; they should have no particular radiation sickness.
Staying on the learned side of WAG, Jupiter likely has the most influence (besides the Sun) on comets, which leave debris in their trail. It’s generally believed that the giant gas planets get in a place just right to tug something out of the Oort cloud that might be a new comet. If such a comet does get pulled in toward the Sun, the gas giants might once again alter its course, closer to or impossibly far from the Earth-Moon. We have nothing definitive; we don’t know whether the Asteroid belt was Jupiter’s influence, and whether it shattered a proto-fifth planet or prevented it from forming in the first place.
The Earth is special amongst the solid planets in having a strong magnetic field that protects us. Whether we’d have evolved to tolerate high radiation either way is definitely a WAG. In any case, the moon does almost nothing to alter radiation exposure in the Earth-Moon system (unless you stay behind it in relation to the Sun)
I’m seeing videos of telescopes tracking Artemis II as it returns, mainly on Instagram, but I’m not buying it.
Because, since Artemis II is returning to us here on this Earth, and if your telescope is also here on this Earth, then why are you showing Artemis II tracking laterally across your screen?
Wouldn’t Artemis II be seen as a dot, barely moving?
What say ye, fellow Dopers? Can I call bullshit?
Example —
I don’t know if the videos are real but it is not to be expected IMHO that Integrity would be a dot getting bigger, the return trajectory is not a direct path.
The craft is still in orbit, it’s just a very eccentric orbit.
NASA’s Astronomy Picture of the Day has a nice animation of the path of Artemis II for those interested.
Sidebar, APOD is an absolutely amazing site, run by two astronomy professors for NASA. May be the best value for the price of anything the US Govt has ever done.