I was thinking that maybe the problem is that he doesn't HAVE any reaction control thrusters. I believe that he only has the one engine, with limited gimbal movement for thrust control.
No.. the vehicle uses an RCS for attitude control for much of the trajectory.
Replying to my own post... someone in the office just made another great suggestion... perhaps one of the reaction control thrusters failed in the 'on' position.
I think they still have some issues with the aerodynamics at this speed.
At the altitude that the roll began there is very little atmosphere, hence very low dynamic pressure and almost no control authority so you can probably rule out any sort of aerodynamic issue. Keep in mind that the spacecraft has very little Ixx (roll) inertial... my money is misaligned thrust vector, either due to a physically misaligned rocket motor or more likely due to asymetric burn of the propellant.
. But separation of powers does not prevent Congress from investigating the executive branch
True statement. Congress certainly can investigate anyone they wish. But at the same time they can not compell the heads of the Executive or Judicial branch to do anything. Thus, they can't compell the president to testify. If Bush had testified in exactly the same manner as all the other witnesses, there certainly would have been an appearance (rather real of imaginary) that he was succombing to the will of the committee.
Thank you for using the word "rapid fundamentalist" rather than "creationist". I am an engineer and scientist who also considers himself a "creationist". However, my scientific beliefs are indistinguishable from those of any astrophysicist except for I give a name to the forces I believe created the big bang whereas a "pure scientist" must stop short.
Um... they didn't have to testify at all - due to separation of powers. Since this wasn't an impeachment hearing (at least not yet) or independent council investigation, the congress has no business investigating the office of the president. All of the stipulations you mention were specifically put in place to change the tone of the interview from being one of investigators investigating the president, to one of two equal branches of government having a dialogue. I think Bush also released some sort of statement saying to the effect that his meeting with the committee was not to be the basis of any future precedent.
What banner would better symbolize politics (considering of course that this is a US-centric site)? Perhaps the word "Slashdot" emblazened across a $100 dollar bill? Or maybe a butterfly ballot?
That is ridiculous. First off, your link assumes that current economic prosperity is somehow causally linked to who the president currently is. I think it would be more realistic to speculate that economic change has a lot of inertia and attibute econimic prosperity to previous administrations/congresses. What that time constant is I have no idea. Along those lines, I would much rather see the same data correlated to who is control of the congress, state legislatures and governors,... all of who probably have more of a real impact on the economy than a sitting president.
I actually had heard that that one wasn't a flight model... in fact, there seems to be a fair amount of discussion on if *any* of them ever made it into space... the Soviets released footage of one landing, but curiously never of one being launched...
A steeper angle requires less shielding. The idea (as I understand it) is to accept a faster increase in heat buildup in exchange for a faster rate of deceleration. Once the craft is deep enough in the atmosphere and has shed enough speed, the atmosphere will actually begin to cool the surface.
First part is true... don't know about the last part. Steep entry trajectories (like capsule entries) have very large but short duration peak heating rates as compared with shallow entry, high L/D entries (like shuttle) which have lower peak heating rates but for much longer duration. Integrating over time, and the steep trajectories actually have a lower total heat load than shallow trajectories. TPS mass fraction is a function of the total heat load so yes, steep entries actually require less TPS mass. On the other hand, steep entires have extremely high peak heating rates, sufficient to melt pretty much any metal. That is why the Mercury program had to switch from a Beryllium heat-sink type heat shield (used during the sub-orbital flights) to an ablative heat shield for the orbital flights. But the steep trajectories also mean that the vehicle penetrates further into atmosphere at comparatively higher speeds than the shallow entry. This means higher dynamic pressures and with it, significantly higher g-loads. The impact of this is more structural mass as well as issues with bringing back sick (or low bone-density) astronauts. For instance, I think the shuttle re-entry peaks at something like 2-3 g's. By contrast, capsules easily can hit 7-9 g's which actually happened recently when a Soyuz lost is attitude reference and reverted to emergency ballistic mode. Not knowing which end was up, the vehicle oriented itself basically zero lift and experienced something like 9+ g's and ended up almost 500 km short. Oh, and the steep trajectories have less down-range travel, thus less opportunity to trade down-range from cross-range, even for similiar L/D values.
Once the craft is deep enough in the atmosphere and has shed enough speed, the atmosphere will actually begin to cool the surface.
As for this, I only can guess that you are talking about radiative heat loss. There are basically 3-4 heat transfer phenomena going on during reentry: (1) covective heat transfer due to the slowing of the freestream as it interacts with the body, (2) radiative heat transfer in that he hot body re-radiates, giving off heat, (3) ablative heat transfer where heat input to the body changes the chemical composition of the TPS, releasing gasses which outflow into the boundary layer, carying significant amounts of heat away and (4) (i forgot what it is called) but when the shock layer gets REALLY hot, the TPS actually starts taking heat radiated from the layer to the body,... not just the normal convective flow. At any rate, when all these heat transfers balance out, you get an equilibream temperature of the TPS. I guess at some point in the trajectory, the heat input (mostly from convective) can go get sufficiently low that the spacecraft's radiative losses win and the temperature starts to cool. Just an engineering guess though that this wouldn't be due to "air" (which would be a convective process) until well out of the hypersonic realm... but like you say.. perhaps some simulations are in order:)
Great idea - not going to happen. Sorta like Microsoft volunteering to pay Linux-related SCO legal costs.
Re:Seems possible to me
on
After the X Prize
·
· Score: 2, Informative
I think you are on to something here... at least up until you mentioned lifting bodies. There is simply *no reason* to use lifting bodies. Yes they are cool looking "landing like a plane". The only things they are good for are giving significant cross-range capability and for reducing the g-loads on re-entry. For the shuttle, both requirements are tracable to the need to launch, fetch (or snatch) a satellite and land again in ONE ORBIT. The low g-load requirement is necessary to prevent damage to the payload, whereas the ability to land in one orbit requires significant cross-range capability to reach a landing site. Now, I can easily imagine scenarios where these would be nice attributes to have in a spacecraft,... but that minimal capability comes at expense of cost, schedule and performance. Wings require more structure, some form of landing system (gear or skis), and control surfaces (most likely triply-redundant hydraulic to man-rate). That adds up to a lot of mass that *can't* be used for science/crew... just to be able to realize a requirement that was never utilized in the shuttle.
Now, I normally don't exhalt the Russians but one thing they have definately done right was in sticking with capsules.
Re:Seems possible to me
on
After the X Prize
·
· Score: 3, Insightful
Strap it to the nose of a Delta II, and you've got yourself an orbiter! With a few modifications, the craft should be able to be modified for reentry
Looks like we need a new moderation category - "Understatment".
How is this story different from say, if a teacher required her students to say the pledge in class or fly a flag from their home? There is not law that requires any of these, and the same arguments about patriotism and citizenship could be made for either. But if we were talking about the the pledge, I'll bet more people would be upset... what is the difference?
Um... more populous states have, by definition, more people in them. Shouldn't the priority be to help the most people possible?
No not really... you have to remember that this coutry was originally designed to have a weak federal government with significantly more powerful state governments than we have today. The federal government, as described in the Constitution, was basically limited to just the sort of things that individual states *can't* do. The first electors were not even chosen as a result of state-wide elections...they were simply chosen by the state legislatures. The office of the president was seen as an office that had to represent the interests of the largest cross section of states not simply the majority of the people.
Today our federal governement is much much stronger... which is what makes the abstraction of the EC so awkward... instead of mucking with the EC, I would rather go back to a weaker federal government and stronger state governments that can better address the needs unique to each state - but thats just me.
The electoral college system is a horrid system--it promotes two candidates that try to be as much like each other as possible to the exclusion of third-party candidates
*bangs head against wall* It's not the electoral college that is the problem. What you are describing is the combination of having an electoral college *and* a winner-take-all system. And while I agree that the winner-take-all is lame... I happen to like the electoral college in it most pristine form... remember, originally people didn't even vote for president. Usually the state legistlatures picked the electors although today they have all given that power to that states' people.
Had Perot not been there, Bush probably would have won; had Nader not been there, Gore likely would have won
I hear this a lot and disagree. Here is my theory. In the case of Perot, the third party candidate siphoned of votes mostly from Bush, but from a political position somewhere between Bush and Clinton. On the other hand, Nader took votes from Gore, but from the further left side of Gore. Why does this make a difference? It makes a difference because in both cases, the third candidate forces the nearest candidate (politically) to redefine himself. For instance, Bush and Perot were very similiar in political ideology, with Perot a shade to the moderate/populist side. To differentiate himself from Perot, Bush had to deviate to the right, therefore alienating the center and ensuring a large turnout (as high as 20% in some states) for Perot. On the other hand Nader, to the left of Kerry/Gore, forced Gore to deviate (slightly)toward the center to highlight his differences from Nader. This has the opposite effect of the Perot effect, in that Gore (IMHO) alienated the far-left, but more than made up for it in new votes from the center moderates. I see the same thing happening here,... Kerry has been forced to the center, IMHO in part because of Nader's presence. This shift to the center has resulted in accusations of changing positions (aka flip-flop) and led to the less-than-enthusiastic support from the far left.
On a somewhat related issue, I would like to add that the maneuvering by the Democrats to keep Nader off the ballot is disgusting and frankly, undemocratic. Anyone know if the Republicans did anything like this in 1992 to keep Perot off? I don't remember anything like this...
Clinton's clear vicotry and Bush's selection by the Supreme Court are not exactly "under the same rules". There was never any question about Clinton's victory. The process worked the way it was supposed to. Bush's selection was not ordinary and was not played by the same rules at all.
This stuff blows my mind... that there are still people out there who cling to the notion that Bush was "selected" and not elected. As for "not played by the same rules at all"... please cite your reference as to exactly which rule was not followed. Start with the Constitution and work down. Good luck.
Actually, it is interesting that you highlighted "state department". The democrat congressmen submitted the request to the state department. The state department had two choices: look partisan and deny the request, or endorse the request. All this says is that the state department plays nice.
actually, the technological advantages of the helicopters, lightweight rifles and jet fighters did destroy the communist army. The turning point of the was was the Tet Offensive, a latch ditch effort by the north to win in which the NVA and Viet-cong forces were utterly obliterated. Unfortunately, up until this point, the American public had been told that the North was just about done... the scale of the offensive made the people back home think the government was lieing about the war and ironicly began pressuring the government to back out, just when the war had essentially been won.
Interestingly enough, in many ways it is superior to the US space shuttle - for example if could do everything automated - including the landing.
Except for the minor detail that the US space shuttles are/were operational with over a hundred missions while this one has how many mission and is rusting in a desert...
Slashdot Mirror
No.. the vehicle uses an RCS for attitude control for much of the trajectory.
Replying to my own post... someone in the office just made another great suggestion... perhaps one of the reaction control thrusters failed in the 'on' position.
I think they still have some issues with the aerodynamics at this speed.
At the altitude that the roll began there is very little atmosphere, hence very low dynamic pressure and almost no control authority so you can probably rule out any sort of aerodynamic issue. Keep in mind that the spacecraft has very little Ixx (roll) inertial... my money is misaligned thrust vector, either due to a physically misaligned rocket motor or more likely due to asymetric burn of the propellant.
Just what I need,... the ability to watch my dog lick his balls via webcam.
True statement. Congress certainly can investigate anyone they wish. But at the same time they can not compell the heads of the Executive or Judicial branch to do anything. Thus, they can't compell the president to testify. If Bush had testified in exactly the same manner as all the other witnesses, there certainly would have been an appearance (rather real of imaginary) that he was succombing to the will of the committee.
Thank you for using the word "rapid fundamentalist" rather than "creationist". I am an engineer and scientist who also considers himself a "creationist". However, my scientific beliefs are indistinguishable from those of any astrophysicist except for I give a name to the forces I believe created the big bang whereas a "pure scientist" must stop short.
Um... they didn't have to testify at all - due to separation of powers. Since this wasn't an impeachment hearing (at least not yet) or independent council investigation, the congress has no business investigating the office of the president. All of the stipulations you mention were specifically put in place to change the tone of the interview from being one of investigators investigating the president, to one of two equal branches of government having a dialogue. I think Bush also released some sort of statement saying to the effect that his meeting with the committee was not to be the basis of any future precedent.
What banner would better symbolize politics (considering of course that this is a US-centric site)? Perhaps the word "Slashdot" emblazened across a $100 dollar bill? Or maybe a butterfly ballot?
Or is it that the Greens and Libertarians make monkies out of themselves resulting in less than 15% poll numbers... just a though...
Need new moderation category: "Didn't get the joke"
That is ridiculous. First off, your link assumes that current economic prosperity is somehow causally linked to who the president currently is. I think it would be more realistic to speculate that economic change has a lot of inertia and attibute econimic prosperity to previous administrations/congresses. What that time constant is I have no idea. Along those lines, I would much rather see the same data correlated to who is control of the congress, state legislatures and governors,... all of who probably have more of a real impact on the economy than a sitting president.
cool beans... never seen that video before... guess someone needs to update the wikipedia entry
I actually had heard that that one wasn't a flight model... in fact, there seems to be a fair amount of discussion on if *any* of them ever made it into space... the Soviets released footage of one landing, but curiously never of one being launched...
First part is true... don't know about the last part. Steep entry trajectories (like capsule entries) have very large but short duration peak heating rates as compared with shallow entry, high L/D entries (like shuttle) which have lower peak heating rates but for much longer duration. Integrating over time, and the steep trajectories actually have a lower total heat load than shallow trajectories. TPS mass fraction is a function of the total heat load so yes, steep entries actually require less TPS mass. On the other hand, steep entires have extremely high peak heating rates, sufficient to melt pretty much any metal. That is why the Mercury program had to switch from a Beryllium heat-sink type heat shield (used during the sub-orbital flights) to an ablative heat shield for the orbital flights. But the steep trajectories also mean that the vehicle penetrates further into atmosphere at comparatively higher speeds than the shallow entry. This means higher dynamic pressures and with it, significantly higher g-loads. The impact of this is more structural mass as well as issues with bringing back sick (or low bone-density) astronauts. For instance, I think the shuttle re-entry peaks at something like 2-3 g's. By contrast, capsules easily can hit 7-9 g's which actually happened recently when a Soyuz lost is attitude reference and reverted to emergency ballistic mode. Not knowing which end was up, the vehicle oriented itself basically zero lift and experienced something like 9+ g's and ended up almost 500 km short. Oh, and the steep trajectories have less down-range travel, thus less opportunity to trade down-range from cross-range, even for similiar L/D values.
Once the craft is deep enough in the atmosphere and has shed enough speed, the atmosphere will actually begin to cool the surface.
As for this, I only can guess that you are talking about radiative heat loss. There are basically 3-4 heat transfer phenomena going on during reentry: (1) covective heat transfer due to the slowing of the freestream as it interacts with the body, (2) radiative heat transfer in that he hot body re-radiates, giving off heat, (3) ablative heat transfer where heat input to the body changes the chemical composition of the TPS, releasing gasses which outflow into the boundary layer, carying significant amounts of heat away and (4) (i forgot what it is called) but when the shock layer gets REALLY hot, the TPS actually starts taking heat radiated from the layer to the body, ... not just the normal convective flow. At any rate, when all these heat transfers balance out, you get an equilibream temperature of the TPS. I guess at some point in the trajectory, the heat input (mostly from convective) can go get sufficiently low that the spacecraft's radiative losses win and the temperature starts to cool. Just an engineering guess though that this wouldn't be due to "air" (which would be a convective process) until well out of the hypersonic realm... but like you say.. perhaps some simulations are in order :)
you mean this one?
Great idea - not going to happen. Sorta like Microsoft volunteering to pay Linux-related SCO legal costs.
Now, I normally don't exhalt the Russians but one thing they have definately done right was in sticking with capsules.
Looks like we need a new moderation category - "Understatment".
How is this story different from say, if a teacher required her students to say the pledge in class or fly a flag from their home? There is not law that requires any of these, and the same arguments about patriotism and citizenship could be made for either. But if we were talking about the the pledge, I'll bet more people would be upset... what is the difference?
No not really... you have to remember that this coutry was originally designed to have a weak federal government with significantly more powerful state governments than we have today. The federal government, as described in the Constitution, was basically limited to just the sort of things that individual states *can't* do. The first electors were not even chosen as a result of state-wide elections...they were simply chosen by the state legislatures. The office of the president was seen as an office that had to represent the interests of the largest cross section of states not simply the majority of the people.
Today our federal governement is much much stronger... which is what makes the abstraction of the EC so awkward... instead of mucking with the EC, I would rather go back to a weaker federal government and stronger state governments that can better address the needs unique to each state - but thats just me.
*bangs head against wall* It's not the electoral college that is the problem. What you are describing is the combination of having an electoral college *and* a winner-take-all system. And while I agree that the winner-take-all is lame... I happen to like the electoral college in it most pristine form... remember, originally people didn't even vote for president. Usually the state legistlatures picked the electors although today they have all given that power to that states' people.
Had Perot not been there, Bush probably would have won; had Nader not been there, Gore likely would have won
I hear this a lot and disagree. Here is my theory. In the case of Perot, the third party candidate siphoned of votes mostly from Bush, but from a political position somewhere between Bush and Clinton. On the other hand, Nader took votes from Gore, but from the further left side of Gore. Why does this make a difference? It makes a difference because in both cases, the third candidate forces the nearest candidate (politically) to redefine himself. For instance, Bush and Perot were very similiar in political ideology, with Perot a shade to the moderate/populist side. To differentiate himself from Perot, Bush had to deviate to the right, therefore alienating the center and ensuring a large turnout (as high as 20% in some states) for Perot. On the other hand Nader, to the left of Kerry/Gore, forced Gore to deviate (slightly)toward the center to highlight his differences from Nader. This has the opposite effect of the Perot effect, in that Gore (IMHO) alienated the far-left, but more than made up for it in new votes from the center moderates. I see the same thing happening here,... Kerry has been forced to the center, IMHO in part because of Nader's presence. This shift to the center has resulted in accusations of changing positions (aka flip-flop) and led to the less-than-enthusiastic support from the far left.
On a somewhat related issue, I would like to add that the maneuvering by the Democrats to keep Nader off the ballot is disgusting and frankly, undemocratic. Anyone know if the Republicans did anything like this in 1992 to keep Perot off? I don't remember anything like this...
This stuff blows my mind... that there are still people out there who cling to the notion that Bush was "selected" and not elected. As for "not played by the same rules at all"... please cite your reference as to exactly which rule was not followed. Start with the Constitution and work down. Good luck.
Actually, it is interesting that you highlighted "state department". The democrat congressmen submitted the request to the state department. The state department had two choices: look partisan and deny the request, or endorse the request. All this says is that the state department plays nice.
actually, the technological advantages of the helicopters, lightweight rifles and jet fighters did destroy the communist army. The turning point of the was was the Tet Offensive, a latch ditch effort by the north to win in which the NVA and Viet-cong forces were utterly obliterated. Unfortunately, up until this point, the American public had been told that the North was just about done... the scale of the offensive made the people back home think the government was lieing about the war and ironicly began pressuring the government to back out, just when the war had essentially been won.
Except for the minor detail that the US space shuttles are/were operational with over a hundred missions while this one has how many mission and is rusting in a desert...