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Happy Thanksgiving. For the TRUE space nerd
hutchphd said:Happy Thanksgiving. For the TRUE space nerd
hutchphd said:Happy Thanksgiving. For the TRUE space nerd
Looks like the checkup results came back good.mfb said:JWST had a mishap in the integration with Ariane 5. Four days delay to check that vibrations didn't exceed specifications, now the launch is planned for December 22.
I fear your nails will have a half year of suffering.DennisN said:I realized it is less than a month to launch, which feels quite weird since I've been waiting for many years now for the JWST.
I'm extremely excited that it hopefully will be operational soon.
But I'm also unusually nervous about the launch.
I would become very disappointed if something bad happens!
Like I said to my friends: if an unmanned Mars mission failed, I would be sad, but rather quickly get over it. :). But if the JWST mission fails, I would be devastated.
I'll be biting my nails when the launch happens. :)
I reckon that could be down to the accountants. A test run with dummy equipment in a low orbit would still cost around $2k per kg (is that the best estimate these days?). If that worked perfectly then it would probably be described as a waste of money.etudiant said:I don't think there is much experience in that process.
Could it be down to poorer Engineering or to more stingy accountants?mfb said:JWST not before December 24
Starliner now aims at May 2022 for its second uncrewed test flight. It was already on the launch pad in August, hours away from a planned launch. This is a repetition of the failed flight in December 2019. Two and a half years (or more with future delays) to fix the issues and try again. In the time between these test flights Dragon has flown 5 crews and 2 more are planned.
According to the Board Expertise analysis, using CGLytics Governance Data and Analytics tools in the software platform, the Company almost completely lacks Technology expertise on its Board. Only recently elected director, Steven M. MollenKopf (elected April 27, 2020), has the professional and industry experience to qualify as a technology expert.
The faint hope is that this debacle may cost Boeing so much money that they recognize that a course change is essential.mfb said:From what I see it's largely a management issue. Once you replace the engineers-became-managers with career managers they'll hire even more career managers who have no understanding of the thing they manage. They do understand costs, and cutting expenses is a great way to spend even more money later, fixing the problems it introduced. You also can't keep the best engineers that way, of course - they go to SpaceX, Rocket Lab and so on.
https://www.bloomberg.com/news/feat...-from-737-max-woes-to-challenge-amazon-spacex
https://www.mondaq.com/aviation/959...but-and-the-role-of-governance-in-spaceflighthttps://www.wsj.com/articles/boeings-other-big-problem-fixing-its-space-program-11610773201

This post has aged very well. With ref to Webb and Luvoir. I don't want to dilute the Webb thread but I thought this was a great comment.mfb said:If you have $100/month disposable income, you probably pay less tax than the average taxpayer. Your contribution would be even smaller.
All these projects are cheap per person and day. There are many of them, of course.
Divide the highest ITER cost estimates by 2 billion (population of participating countries) and you get $10 per person, or ~0.1 cent per day over 25 years. For the option to have a very clean energy source in the future? Build two of them!
The US and many European countries spend about 3% of the federal/country budget on research. We could double science funding if everyone would be fine with paying 3% higher taxes. In the US that would be about $1.2 per person and day on average, in Germany it would be something similar but estimating the number is complicated.
I'd happily pay that. Okay, I am biased, because my income is from this budget item...
Much less of a fuss to re-enter from sub-orbital compared with re-entry from orbit. Less potential energy to get rid of and no kinetic energy.mfb said:the suborbital tourism flight in December.
Although for a higher suborbital flight the g forces associated with a ballistic re-entry can be very high. The flight profile of manned launches is adjusted to mitigate these possible high g reintries if abort is necessary part way to orbit. The unsuccessful Soyuz 7K-T No.39 launch to the Salyut space station produce more than 20g for the cosmonauts during their return.sophiecentaur said:Much less of a fuss to re-enter from sub-orbital compared with re-entry from orbit. Less potential energy to get rid of and no kinetic energy.
That's pretty reasonable but g is not the only factor because what you have written doesn't consider how dissipation of the total orbital kinetic energy can be dealt with. It seems that either the craft has to get hot or rocket braking has to be used for orbital re-entry. All that is in addition to your idea that the entry trajectory has also to be tailored to mitigate against g forces.hutchphd said:My understanding of the issue is the trade- off between vertical and horizontal speed and the increasing air density closer to the surface. One does not want to hit the dense atmosphere too soon coming down.
Shephard had 11 gees max on reentry after a peak speed of 8200 mph. Glenn had 6 gees reentry (8 gees on the way up) after orbital re-entry
I know that the crew dragon follows a more shallow climb to orbit than is maximal for this reason, but I don't find a quantitative treatment and I haven't worked it out myself.
Sigh, I'm dense sometimes, and I can't keep the different competing space tourism companies straight. I read those times as military time (Army brat and Medic here), and thought, "Wow, what a boring 9 hour wait just sitting there before takeoff. At least they had a couple hours of weightlessness...".mfb said:8:50 capsule is closed
17:50 takeoff
20:20 they unbuckle and float around in the cabin
22:50 back to the seats
~26:10 parachute deployment
27:40 touchdown
35:30 unbuckling

Absolutely the energy either gets radiated, ablated or shock-convected for passive re-entry. The other factor is the aerodynamic lift available to all spacecraft since Mercury (and Vostok) because the center of mass is off the center line. I think the Apollo did a dipsy-doodle coming home make the re-entry aiming requirements less stringent and the period of high radiative loss more effective. Sounds a lot like rocket science to me.sophiecentaur said:but g is not the only factor because what you have written doesn't consider how dissipation of the total orbital kinetic energy can be dealt with. It seems that either the craft has to get hot or rocket braking has to be used for orbital re-entry.