SpaceShipOne Flight Completed Successfully 998
knothead99 writes "CNN is reporting the successful liftoff of SpaceShipOne from a runway in the Mojave desert. Around 10:30 EDT the craft will reach an altitude of 50,000 feet and they'll separate from White Knight and ignite the rocket for space entry. More information can also be found at the Mojave Airport website" Update: 06/21 15:36 GMT by S : An MSNBC story confirms that SpaceShipOne 'glided safely back to Earth, landing back at the Mojave Airport' around 8.15AM PST.
And More importantly... (Score:5, Informative)
Private craft flies into space (Score:3, Informative)
Space.com
Updates
11:08 a.m. ET: Mike Melvill and his SpaceShipOne have made it into space. Everything looks good, mission official said, and the craft is now gliding back toward a landing at the Mojave Airport, where it took off earlier this morning. "I got goose bumps when I saw contrails," Greg Klerkx, author of Lost in Space: The Fall of NASA and the Dream of a New Space Age. "I never thought I'd see this moment, but here it is."
It has already landed (Score:2, Informative)
Touchdown! (Score:2, Informative)
Note that this is a sub-orbital flight but Burt has said that he eventually wants to go full orbital.
Jib
blow by blow (Score:5, Informative)
Just refresh your page to get the newest news.
Re:Question (Score:1, Informative)
Re:Question (Score:5, Informative)
Quick FAQ (Score:3, Informative)
A: Yes. Private spaceflight is huge.
2. Does this win them the X-Prize
A: No. They've got to do it twice, in quick succession.
Re:Question (Score:5, Informative)
Here [nasa.gov] is a nice orbital velocity calculator.
Getting up to that speed is not the only problem, you have to loose all that kinetic energy before you land, unless you fancy spreading yourself thinly across a continent.
Re:Question (Score:5, Informative)
For more information see this article from ScienceWorld [wolfram.com]
From live coverage on CNN (Score:5, Informative)
As a result, they weren't sure if they reached the 100km mark at first, but were told they did afterward.
On the glide back to the landing strip, some loud pops were heard coming from the back of the rocket. Chaser planes inspected, and reported everything looked ok.
Hooray for private spaceflight!
More on space.com (Score:3, Informative)
Wonderful! (Score:5, Informative)
Re:Quick FAQ (Score:2, Informative)
Re:Question (Score:5, Informative)
Low Earth Orbit is 350 km (217 mi). Obits lower than this are not stable.
In addition, they would have to be going about 8 times faster to reach orbit.
Re:Quick FAQ (Score:3, Informative)
That's what is needed to get the X-Prize, and this was one very large step to making that goal!
My (late) submission (Score:5, Informative)
"Space flight is not only for governments to do," Rutan said. "Clearly, there's an enormous pent-up hunger to fly into space and not just dream about it." "We are heading to orbit sooner than you think," he said. "We do not intend to stay in low-earth orbit for decades. The next 25 years will be a wild ride.
Re:Early shutdown? (Score:5, Informative)
Nothing here...move along.
Re:Early shutdown? (Score:5, Informative)
"For a few minutes after SpaceShipOne began its descent, it was unclear whether Melvill had reached his goal. But the mission announcer finally said the mission had been successful as the craft prepared to land at Mojave Airport, accompanied by three chase planes. "
Looks like Globe and Mail just jumped the gun. thpt.
Re:Question (Score:1, Informative)
Hey! That's my goal too!
Panel was buckled aft. (Score:5, Informative)
On the way back (I think after completing the 'feather'), Mike reported a 'loud bang' and his chase plane, the Alpha-Jet reported that an aft fairing had buckled.
When they got back down they were saying that they suspect the loud bang was caused by that same panel.
Definitions and achieving orbit (Score:5, Informative)
Achieving orbits is a 2-step process. You need to get high enough that the atmospheric drag is small enough that it's possible to acheive orbital velocity. Then you have a vehicle with enough thrust to kick you into orbit. Height/velocity isn't the only issue. If you accelerated a vehicle to escape velocity at the earth's surface, it would have the energy to leave the earths gravity well completely; however, the energy would turned into heat by friction with the atmosphere, and the craft would be vaporized.
Still below the X-15 flight of 1963 (Score:5, Informative)
The X-15 could do everything required to win the X-prize except carry three people. It reached 100km, and it was flown repeatedly, for a total of 199 X-15 flights of three aircraft.
Re:Question (Score:5, Informative)
A spaceship is not launched like a cannon, but rather, it has engines on it that provide thrust. In this way it is possible to escape Earth's gravity with continual acceleration and never actually experiencing speeds of Mach 25. You are right, to get into a low-Earth orbit one would need to be travelling at Mach 25, but that is simply a result of the Newtonian mechanics of an orbit plotted at that arbitrary altitude. Any number of different orbits - such as a parabolic orbit arcing away from the Earth - could have any number of different (higher or lower) necessary velocities.
And besides, once you are in space, without having to worry about air resistance, it's trivially easy to build up that extra velocity. Your post makes it sound like getting to Mach 3 is trivial and they need to put in eight times the work to reach LEO. This is simply not true. Getting to 100km through most of the atmosphere has already accomplished most of the work. The rest is easy. It's not as simple as looking at the difference between the numbers 3 and 25 and saying, "Oh, they have eight times more speed they need to get!"
Re:America's first inland spaceport? (Score:4, Informative)
Re:Early shutdown? (Score:3, Informative)
Except they didn't. (Score:3, Informative)
By the time you factor in extended life support and the heat shielding needed to survive reentry, orbital flight becomes a much thornier problem that almost certainly won't be solved in a decade.
Free video link (Score:5, Informative)
Re:I never thought (Score:1, Informative)
>would see commerical space flight in our life
> time
You still haven't I'm afraid. Rutan has built a vehicle that can attain a 60 mile altitude...AND COMES IMMIDIATELY DOWN again.
What's he's done is little different from shooting a man out of a slick looking cannon that can happen to blow him 60 miles high.
To actually ORBIT a craft must reach about 18,000 mph give or take....rutan's craft can only go about 1,500 mph....not even 10% of what's needed to achieve orbit.
And don't forget...to go that fast you need special materials to withstand the heat effects (>1000 degrees F) that occur at such velocities when back in atmosphere.
Rutan's kind of a hero of mine but I am forced to keep things in perspective. He's built a BIG cannon that can launch someone 60 miles high nd come back down again...but he's NO WHERE NEAR achieving a true suborbital flight which needs HORIZONTAL velocities AT LEAST 5 to 10 times what he could possibly hope to achieve now with his current design.
He'll win an X-Prize..but he needs another vehicle design to make a REAL space ship. IMHO there's a BIG hype factor going in here.
Re:I never thought (Score:5, Informative)
You're too young to remember that we've been here before. Kennedy went to space for political reasons too. Americans were trying to one-up the Russians. Check this [space.com] and this [space.com] out. For those who don't like to RTFA:
Re:Early shutdown? (Score:5, Informative)
Re:Chase planes? (Score:5, Informative)
Re:Mojave NOT America's first inland spaceport! (Score:1, Informative)
Wow, it's been a while since I've been there. Are they even in business anymore?
For those people that aren't from the U.S., Spaceport is an arcade chain.
Re:Question (Score:5, Informative)
It gets worse: currently they're hardly addressing *the* most difficult concept for cheap reusable spacecraft: reentry. This single problem has contributed to the majority of the space shuttle's turnaround cost. Standing on the shoulders of giants (as the vast majority of their work thusfar has been), they can at least avoid the ceramic tile mistake; however, they still need to solve the problem somehow.
They're not 3/25ths done - they're *less* than that.
"less than 12 parsecs" explained (Score:4, Informative)
First of all, you meant "distance, not time"...
Secondly,
Read this and then STFU. [starwars.com]
Re:"2001 Odyssey": commercial space flight by 1980 (Score:5, Informative)
You mean the Truman, Eisenhower, Kennedy, Johnson, Nixon, Carter, Reagan, Castro, Krushchev, Brezhnev, Andropov, and Gorbachev Cold War don't you? It's not like Reagan started this all on his own in '46.
My apologies to readers from the UK for leaving out Churchill from that list (given that he coined the term "Iron Curtain").
Re:Question (Score:4, Informative)
-
Rocket Equation Calculator [telus.net]
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Specific Impulse [af.mil]
For a 400 s specific impulse, getting to mach 3 requires a 1.276 takeoff to payload ration. On the other, making Mach 25 requires 7.66 takeoff to payload ration. That's why Spaceship One is self contained, whilst the Shuttle requires vast external fuel tanks and external boosters. It's hardly trivially easy.Re:Chase planes? (Score:2, Informative)
Chase planes also supply you with a moral boost. Even though they can't get out and help you, it's still kind of nice to know that there is another human being who is close enough that you can see him when you're locked in a small metal box miles above the ground all by yourself. (I've flown chase before when a squadron member's jet developed problems on a routine training flight).
And last of all, the people in the Chase planes usually know as much about your plane as you do. And can provide advice when you really, really, need it. Especially as they're right there looking at the situation.
Re:Next stop: Kessel run (Score:4, Informative)
The parent post was correctly quoting Han Solo from Star Wars: A New Hope. So if you want to nitpick on units you probably need to contact George Lucas directly.
Aside: I can't believe that I'm actually having to explain this to anyone who reads Slashdot :-p
Re:Question (Score:5, Informative)
Re:Question (Score:5, Informative)
So as long as the ship has the guts to get far enough from the earth, it can certainly go fast enough to be in orbit.
=Smidge=
Re:blow by blow (Score:5, Informative)
The ISS has lifeboats with enough capacity to get everyone down without help from Earth. That's one reason why they never had more than three people on it at a time, because there is currently no vehicle capable of acting as a lifeboat for more than three people. Even if all spacecraft on Earth disappeared tomorrow, they'd be able to get back fine.
Re:blow by blow (Score:5, Informative)
Melvill: ""Man!" Melvill said, shaking his fists together as he climbed from SpaceShipOne. "I went pretty high, though. When I got to the top, I released a bag of M&Ms in the cockpit. It was absolutely amazing. M&Ms were going all around. It was so cool! We have got to have video of that because I did it in front of one of the video cameras. I haven't ate them. They are in the cockpit."
Imagine a NASA astronaut doing that on a maiden flight...
Re:Question (Score:5, Informative)
I disagree that it's easy. Although accelerating at a height of 100km isn't too hard, you need to get the fuel and oxidizer up to that height and keep burning it. Carrying enough propellants up through the atmosphere in order to burn your way up to about 7,500 m/s velocity is pretty difficult.
Another way to look at it is to use the equation for kinetic energy (1/2*m*v^2). Since it's proportional to v-squared, if you need 8 times more velocity, that's 64 times more energy. As you say, "The rest is easy." :)
Re:Question (Score:1, Informative)
Re:Question (Score:4, Informative)
No grandparent is probably closer to being correct.
At the top of the flight, SSO was about 100km above the earth with no radial velocity and essentially no tangential velocity. The escape velocity needed from this state is still more than the orbital velocty at 100 km. That is the additional energy needed to escape the gravitaional pull of the earth is still more than the additional energy to needed to get it into a circular orbit. Now maybe you could start from the top of that orbit, with an amout of fuel 4 to 8 times the amount required for this flight and get enough speed for orbiting. But wait a minuite, you've increased the mass that needs to be lofted to this heght by a factor of say 3 -6. That means you'ld need to have initially double that amount when you lauch from White Knight to get SS one up to that 100km height. In other words you're talking at least 7 or 8 times the fuel to begin with. The amount of fuel required to reach a given velocity grows exponentially (not linearly) with the velocity. (kind of sucks, doesn't it).
Re:Question (Score:5, Informative)
You MUST be trolling.
YOu are simply incoprrect when you say that you do NOT have to reach 25,000 (or Mach 25 as you out it) to escape Earth's gravity because of the *engines* on a craft sigh). In point of fact you simply DO.
Out and out wrong. The escape velocity is merely the speed at which the craft would be traveling if it had fallen toward the Earth from infinity. You do not have to travel at the escape velocity to move away from the Earth. If you have a source of thrust, you may move at whatever velocity you please.
The rest of your post is (unfortunately) just a layperson's opinion about physics and I'm sorry but a rather poor opinion at that.
And you're what, a professional physicist? Certainly not, since your error is a grievous one.
At any rate, your post should be marked "troll," not "informative."
Some milestones for comparison (Score:2, Informative)
On April 12, 1961, Soviet cosmonaut Yuri Gagarin became the first human in space. His remotely controlled Vostok 1 spacecraft lofted him to an altitude of 200 miles and carried him once around planet Earth. (Source: NASA)
[Alan Shepard] holds the distinction of being the first American to journey into space. On May 5, 1961, in the Freedom 7 spacecraft, he was launched by a Redstone vehicle on a ballistic trajectory suborbital flight--a flight which carried him to an altitude of 116 statute miles and to a landing point 302 statute miles down the Atlantic Missile Range. (Source: NASA)
The X-15 research plane had some mission similarities to SpaceShipOne. The X-15 was lifted under the wing of a B-52 bomber to around 45,000ft and was then dropped before its rocket engines were fired and testing began. One of the primary purposes of the X-15 was to test the physiological effects on both man and machine of high-speed, high-altitude (near space) flight. The information gathered certainly qualified as high altitude as even under NASA's strict guidelines Joe Walker achieved astronaut status while testing the X-15 on August 22, 1963 by going over the 62 mile mark--to an altitude of 67 miles. (The US Air Force recognizes the limit as 50 miles, under this system many prior X-15 pilots reached "astronaut status." It is interesting that NASA's mark was only passed after they had taken over the X-15 project on 1960.) (Sources: various)
The pilot of SpaceShipOne, Michael Melvill, brought the ship into a vertical ascent at Mach 3, or three times the speed of sound. The craft coasted in a massive arc, about 100 kilometers, or 62 miles, above the Earth. Melvill, the first astronaut to pilot a private spacecraft, experienced weightlessness for about three minutes. (Source: CNN)
Re:I never thought (Score:5, Informative)
And little different from what Alan Shepard did in the original Mercury/Redstone launch. But it's a start. And it does count as "space flight".
And don't forget...to go that fast you need special materials to withstand the heat effects (>1000 degrees F) that occur at such velocities when back in atmosphere.
That's not necessarily true. There have been designs for aluminum-based thermal protection systems. Of course, most of them make use of complex transpiration-cooling systems to stop the aluminum from melting :-) Personally, I would wager that Rutan and Co. will go with some form of ablative shielding (like the old Mercury/Gemini/Apollo capsules), probably a spray-on ablator that can be reasonably quickly replaced. That kind of approach seems in line with the general philosophy of the SpaceShipOne design (for example, their use of a hybrid rocket engine).
but he's NO WHERE NEAR achieving a true suborbital flight
Actually, they just achieved suborbital flight. It's orbital flight that they are still a ways from achieving.
Re:Question (Score:3, Informative)
Re:Still below the X-15 flight of 1963 (Score:3, Informative)
Without replacing more than 10% of the crafts zero fuel weight???
I dont think so.
also, the X-15 wasnt very stable, especially at high altitude (inertia coupling was a very real danger) and made the approach for landing at just around 300 knots (thats 555km/h or around 350 mph)(for comparison a LARGE passenger jet makes an approach at around 140kts)
Finally the x-15 was bigger and heavier than SS1 needed a bigger drop-vehicle, and had a highly explosive and complex liquid fuel engine producing 57.000lbs of thrust (dont know what SS1 pruduces, but substantially less than that!)
X-15 weighed in at 32.000 lbs
SS1 is around 6000lbs
I reckon these craft cant easily be compared, theyre just designed for such vastly different purposes, although one feature coincides (going high)
Re:I never thought (Score:5, Informative)
Re:Question (Score:5, Informative)
The truth has a tendency to be true, unlike your post. Let me just give my background for disclosure - I'm a rocket scientist.
No, you don't. If you were blasted off from the surface of the Earth at Mach 25 and the atmosphere didn't exist, then (to use the kind of lax definition of infinity that us physicists are proud of) you'd come to rest at infinity and wouldn't fall back into the Earth. However, if you provide a continual thrust that everywhere is greater than the local acceleration due to Earth's gravity, you will never fall back down. You could achieve this at a constant velocity of 1m/s if you liked, by suitable modification of the thrust.
To go forward in space, throw something backward. To go forward in the atmosphere, throw enough stuff backward to push enough air out of the way. It's easier in space - as you don't have to overcome resistive drag (unless the solar wind is non-negligible) then the same acceleration can be had for less driving force - the net force is the same yes. This means you can take it easy, and do something like throwing photons or ions out of the back of your spaceship.
As opinions go, it was just as valid as anyone else's. As statements of physical understanding go, it was superior to yours.
Re:Definitions and achieving orbit (Score:2, Informative)
Actually, that's a misconception. The atmosphere is heated by the compression of the air in front of the object, not by friction.
Re:Question (Score:2, Informative)
Energy at t=0 = energy at infinite distnce from earth
1/2mv^2 - GMm/R = 0
where M = mass of the planet m = mass of the rocket R = distance from the rocket to center of the planet
ie v = sqrt(2GM/R)
Re:Question (Score:5, Informative)
Re:Question (Score:5, Informative)
Getting into orbit is way, way, way harder than getting to 100km. It takes 24 times the energy to get to orbit, and you therefore need massively larger fuel tanks and engines to do so. You are correct that "eight times more speed" is misleading, but you got it backwards; since kinetic energy goes up as the square of the speed, you need more than eight times the energy to reach orbit.
Re:Chase planes? (Score:1, Informative)
Re:Question (Score:4, Informative)
It is also true that escape velocity must be reached at some point or the object will fall back to earth *if it is not being acted on by another force*. It would be possible to operate under thrust for the entire duration of your trip-- and as long as your thrust is just a hair above g, you'll gradually rise. You could thrust your way into space at 1mph, if you had the fuel for it. This isn't practical currently, and of course, you fall right back when you turn your engine off.
All I'm (and the original poster) are trying to point out is that telling "laypeople" that you have to reach escape velocity to leave earth is not the whole truth. You can leave as slow as you want and pick up the orbital velocity later, or just hover on your engines and never pick up any speed at all. Not that you'd want to.
Comment removed (Score:2, Informative)
Re:But can they do it TWICE in two weeks, for the (Score:3, Informative)
Re: YES The da Vinci project! (Score:5, Informative)
Yes the Canadian Team called The da Vinci project [davinciproject.com]
"The da Vinci Project, led by Brian Feeney of Toronto, Ontario, Canada, registered as a contender for the X PRIZE on June 2, 2000. A reusable helium balloon will lift our spacecraft, "Wild Fire" to an altitude of 80,000 feet. This is where Wild Fire's rocket engines will fire and propel the crew to the 100 km altitude goal -- space."
They developed the project in a kind of "open process" way; every people who wants to contribute is invited to join the project and can even open a local club in is university. They accept help from people of all fields: engineering, public relations, marketing etc...
"The all-volunteer da Vinci project is the largest volunteer technology project in Canadian history with upwards of 100,000 man-hours having been spent on the project thus far."
They amased a huge amount of sponsers and are well advanced in the project.
Physics. Orbit. (Score:5, Informative)
In orbit, you'll circle the earth every 1.5 hours. That means a speed of about 7.4km/sec. This requires (again per unit of mass) 1/2 * v^2 = 0.5*7400^2= 27 MJ/kg.
So, reaching (low earth-) orbit requires about 27 times more energy than what was demonstrated now.
Now there are a few things to keep in mind. You'll have to lug along the fuel to accelrate the last part of your ascent. That means that just taking 27 times more fuel won't cut it.
We're at least two orders of magnitude away from commercial manned spaceflight. (where spaceflight is defined as "in orbit"). Sure: Big step, but not quite there yet....
Re:Definitions and achieving orbit (Score:3, Informative)
"We chose 100km altitude because it is beyond the official 50-miles that the US Air Force recognizes as "worthy of astronaut wings" but not so high that the re-entry speed requires exotic heat shielding."
Re:Still below the X-15 flight of 1963 (Score:5, Informative)
Re:Question (Score:2, Informative)
What he stated about "leaving the surface at ~25k mph will result in zero velocity at infinite distance" is true. It is a statement of initial vs. final energy. 25k mph is the required escape velocity at the surface of the earth, or just outside the atmosphere, since it's pretty thin when compared to the earth's diameter.
Actually reaching 25k mph is NOT required. You could make the trip to some intermediate point at a lower velocity (forget about acceleration, it's not important in this discussion) as long as your velocity at burn-out is greater than or equal to the local escape velocity. So yes, if you had LOTS of time and LOTS of fuel, you could make the trip to infinite distance at 1 m/s.
Nowhere in Mr. R.S.'s post did he confuse acceleration and velocity. As long as your spacecraft provides enough thrust to overcome the local gravity and drag, then you will not fall back down. If your thrust is more than enough to overcome gravity and drag, then you will accelerate.
Next time you want to discredit someone who knows what they're talking about, I suggest you make sure that you know what you're talking about too.
Re:blow by blow (Score:3, Informative)
Well, Alan Shepard was sitting in a spacesuit full of urine, does that count?
According to Chuck Yeager, all of the Mercury astronauts were sitting in monkey [expletive deleted].
Re:Question (Score:5, Informative)
One Air Force requirement that had a critical effect on the Shuttle design was cross range capability. The military wanted to be able to send a Shuttle on an orbit around the Earth's poles because a significant portion of the Soviet Union was at high latitudes near the Arctic Circle. The idea was to be able to deploy a reconnaissance satellite, retrieve an errant spacecraft, or even capture an enemy satellite, and then have the Shuttle return to its launch site after only one orbit to escape Soviet detection. Because the Earth rotates on its axis, by the time the Shuttle would return to its base, the base would have "moved" approximately 1,100 miles to the east. Thus the Shuttle needed to be able to maneuver that distance "sideways" upon reentering the atmosphere.
Given a choice between straight and delta wings, the latter perform much better in terms of cross range capability. Delta wings produce more lift at hypersonic speeds, enabling more maneuverability (Heppenheimer, p. 220). Given the requirement for cross range capability, a delta-winged vehicle became the clear choice. Additionally, delta-winged vehicles do not heat up as much as straight-winged vehicles during atmospheric reentry (Draper et al., p. 26), thus decreasing the need for expensive and potentially heavy thermal protection systems, although the thermodynamics are too complex to cover fully in this paper. Moreover, some aerodynamicists argued that delta-winged vehicles were a proven technology that provided good balance, stability, and aerodynamic control (Draper et al., pp. 29, 35).
Now you know why the Space Shuttle has stubby delta-wings for hypersonic flight. I'll see if I can dig up some other links.
Re:Question (Score:5, Informative)
The air force wanted "large cross range capability", in other words, the ability to glide in large distances. The Air Force's desire for 1100 miles of cross-range doesn't put the shuttle anywhere near the capability of doing a low altitude flyover of Soviet airspace-- Florida is a LONG glide from Russia for something that effectively drops like a brick.
The nefarious use of cross range capability would be for the Shuttle to be able to enter a polar orbit, grab a spy satellite, and come back around and land in the same field. The problem is, in the hour and a half that orbit would take, the Earth would rotate about 22 degrees. So for the Shuttle to land at the same field, it would need to glide about 1000 miles (depending on how far from the equator it was).
This has pretty obviously not been used. But the versatility that the high cross range capability provided has greatly eased shuttle operations and also makes the vehicle safer by adding additional abort capabilities.
Another point: cross range capability has nothing to do with the heat shields. The Shuttle has a huge amount of kinetic energy that has to be dissipated one way or another; and really, you don't have a lot of choice in how quickly you aerobrake. The high cross range capability required more wing area and wing mass; and if you had a lower surface area to mass ratio, you'd actually aerobrake more quickly and require additional shielding.
AoA doesn't really come into it much. Once you enter the atmosphere, you're losing huge amounts of velocity. At hypersonic velocities, L/D ratios are awful, pretty much no matter what your AoA is.
Re:Early shutdown? (Score:5, Informative)
There is no sonic boom associated with travelling at multiples of the speed of sound, since at multiples of the speed of sound it just leaves it's noise further and further behind.
Re:"2001 Odyssey": commercial space flight by 1980 (Score:2, Informative)
Stalin was still the Soviet leader until 1953.
Malenkov was First Secretary before (and along with) Khrushchev.
Chernenko was only General Secretary for a 13 months, but still managed to escalate the cold war.
Re:blow by blow (Score:3, Informative)
But the countdown kept getting interrupted, and he again contacted ground, almost begging them to give the green light... Eventually they did.
Design notes: cheaper, safer, faster turnaround (Score:4, Informative)
Also mentioned is the shuttle design that makes it self-orienting on re-entry thus always having it re-enter on a "least friction" path.
Various design differences would appear to make the shuttle inherently safer than the 30 year old NASA design.
The article also mentions the cost on the project, $69 million, is less than most government studies and considerably less than the 1 billion dollar cost of the US Shuttle and the per-fligh cost of $500 million.
-l
Re:Chase planes? (Score:3, Informative)
They can also do handy things like make sure the pilot isn't incapacitated, make better judgement calls on an aircraft's condition, etc..Chuck Yeager detailed several stories of just how valuable a chase plane is.
On one occasion his windshield defroster failed, leaving him flying exceptionally blind. His chase plane helped talk him down by flying parallel to him and directing the plane in. (I know, he had instruments, but think about a frost covered windshield on a bright sunny day. You're pretty much flying with your eyes closed)
In another case a pilot yeager was flying chase for neglected to turn his oxygen up. Yeager conned the pilot into returning to a safe altitude.
Thermal protection system (Score:4, Informative)
Just got back from Mojave (Score:5, Informative)
Mojave airport is really cool in itself, no fences around and you can wander all over if you want. We got some good spots as near to the takeoff and landing as possible ( they did restrict where you could watch the event, and the ships wheels actually left the ground about 50 yards north of us) and camped out. Everybody around was really excited. Many had come from really far away, like this pair of guys we met from Seattle. I'm sure that there were many who were from much further than that. There was a big mix of people. Lots of old timer aviation types, college age kids, and families. I'm sure much of the town of Mojave were there. We talked to this one guy who was bringing a group of kids from the local high school who were in their special engineering program(something I didn't have at my HS).
When they announced that the ship was actually going to take off on time I was pretty surprised. I just had a feeling it was going to be delayed. At about 6:40 the low altitude chase plane took off, it was a bright red little single engine plane which according to the announcer was flown by the spaceshipone pilot the night before in order to pull 6G's so that he could go to sleep! Next (I think) came the medium altitude chase plane, which was this really cool and modern looking craft with propellers in the back and a little wing on the nose. Then came White Knight, carring SpaceShipOne which look completely unorthodox and bizarre in person, even if you've already seen pictures of them. It taxied along the tarmac that ran past the crowd did a U turn then sped up and soared off of the runway to a cheering crowd. As everybody watched the ship gain altitude, the high altitude chase taxied and lifted off. This jet was pretty interesting, It sort of looked like a fighter jet that had been squashed to make it all squat lookin, sort of a caricature of a fighter jet. The ship climbed really slowly, about an hour of circling around the airfield getting smaller and smaller. Then we got the word that the rocked was going to take off . The ship was about 2/3 of the way almost directly between the horizon and the sun (the sun being fairly low since this is about 7:45 am). Then all of a sudden this huge contrail appeared and traveled straight up just to the right of the sun traveling at an amazing speed. The crowd loved it , after watching the ship climb slowly for an hour this was really dramatic. The trail kept moving up until it seemed to be about 70degrees above the horizon when the engine cut off. After a few minutes with everybody searching the sky for the craft *boom*, a little sonic boom let loose and the ship then appeared. It circled around a few times on its way down and met up with the chase planes. They all flew in a pretty tight formation and the ship finally made an amazingly smooth landing considering it was an unpowered odd looking bulbous craft. Everybody was ecstatic as SpaceShipOne rolled by, this odd looking craft had reached the edge of space and had made it back in one piece. After that, the low altitude chase plane made a flyby, which was pretty cool but then the topper was when White Night flew towards the crowd then pulled up proudly displaying it's bizarre silouette.
I'm really really happy that I got to have this experience. This amazing flight was the first time in my 19 years that I felt that I was actually witnessing history being made with my own eyes.
Re:Question (Score:3, Informative)
By the way, contrary to popular assumption Dr. Van Allen is still alive and still working at the University of Iowa as a professor emeritus. His autobiography is here [uiowa.edu]
Re:Just got back from Mojave (Score:5, Informative)
*Thanks*, ambulance chasing lawyers.
Re:Question (Score:5, Informative)
Re:Still below the X-15 flight of 1963 (Score:4, Informative)
Without replacing more than 10% of the crafts zero fuel weight???
I dont think so.
I do.
Flights 167 and 170 of the X-15-A2 craft occurred 18 days apart, in August of 1966. These weren't altitude runs, though, they were speed runs as the A2 was modified to have longer engine burn times in order to support higher speed flights.
87, 90 and 91 were each spaced around a month apart, and the latter two were over 100km in the X-15A (3rd vehicle). The first was 86km. June 27, July 19, August 22 were the dates. In 1963.
Refurb % between flights for X15 is not an easily available number, but it's likely it was less than 10%; there was no ablative structure and the engines were reusable. This wasn't a bloat-era NASA program; it was originally a joint USAF/NACA project, which means that the ground crew wasn't huge and major overhauls between short flights were pretty much impossible.
The stability problem was mostly overcome with adaptive control systems; these days it wouldn't even be an issue, controls have gone so far along with easy access to DSP and computation. As to landing, the high speed was a result of a relatively low subsonic L/D ratio; X-15 was optimized for hypersonic flight, while a jet is optimized for subsonic flight. As a result, X-15 had a much harder time staying in the air at low speeds, and stalled at a higher speed, meaning it had to land at a higher speed. SS1, not being designed for maneuverability at hypersonic speeds, could be more optimized for subsonic landing, which is why it lands at a relatively paltry
X15 weighed around 30000 kg, not pounds. It produced 26762 kgf of thrust. By comparison, SS1 is 3600kg and produces 7500 kgf. X15 did nearly as much as this initial flight, despite a significantly worse thrust-to-weight ratio.
And let's not forget, the X-15 flew in the mid 60s. 40 years ago.
I give Rutan a lot of credit, but the X-15 remains one of the most amazing accomplishments in aerospace history, and was capable of most things the X-Prize asks for (obviously, the 3 man requirement not so much).
Re:Question (Score:3, Informative)
=Smidge=
Pictures & story (Score:3, Informative)
Re:Question (Score:2, Informative)
Re:Question (Score:3, Informative)
Re:Question (Score:2, Informative)
Look, the statement that we are dealing with is "you MUST reach 25,000mph to escape the gravitational pull of the Earth," not "it is more efficient/practical with current means to reach 25,000mph to escape the gravitational pull of the Earth." If you're going to argue against something make sure you know what that something is.
If you would like a potential real life scienerio in the future, look to the concept of the space elevator. Cimb it up to the point where you're in a perfect geosynchronous orbit with the planet (approximately 22,236 miles). Climb it at any speed you want using any energy source you want, it need not be 25,000mph using a chemical rocket. Once you're there, leave the elevator. Take a rock (you did remember to bring a rock, right?), chuck it down to the Earth. Congratulations! You have reached escape velocity, and the fastest you have traveled is just a smidge over 6,876mph (your tangential velocity).
Re:Definitions and achieving orbit (Score:3, Informative)
It's important to note that it's only half-way to the minimum altitude of a stable orbit.
Thanks! (Score:1, Informative)
OTOH, I probably had a better view of the landing, and especially Mike Melvill's victory celebration when he stopped in front of us and accepted a sign from one of the crowd.
It read: "SpaceShipOne. Government Zero"
Helluva show!
Eyewitness report (Score:1, Informative)
First, two chase planes took off. One, the Extra, is a prop-driven single engine aerobatic plane that's very fast, and is used to follow SS1 down to the runway on landing. The other is a Beech StarShip, also a Rutan design, a twin turboprop bizplane that's used as chase during climb to launch altitude. The third chase, an AlphaJet, took off after the launch aircraft.
I was surprised at the climb performance of the White Knight. I'd expected a shallow climbout commensurate with the considerable load of SS1, but the package absolutely leapt off the runway and was probably over a thousand feet before it left the airport boundaries. White Knight is a twin turbojet plane, and clearly has lots of performance margin in its role as launch/carry craft. Our vantage point was perfect - the rising sun behind us lit up the fab paint job on the launch package to good advantage, and after hammering our ears on its overhead pass, they started their climb to launch altitude.
We lost sight of them during climb several times, as it's hard to keep a small target in sight in a dusty blue sky, especially when their path approached the sun. It got easier when they reached about 40K feet, where they wtarted laying down a contrail.
At launch, they were too high to resolve with the unaided eye, mine, at least. At ignition, we immediately saw the exhaust track headed down for a couple of seconds until airspeed built up a bit. Then it curved sharply upward, locked on vertical and kept going, going, going! Burnout was an abrupt event, no doubt about it as the plume disappeared. There was lots of wind shear aloft, we could see the plume spread every which way at many levels. It was probably a choppy ride, and I'll look for the after flight writeup in Aviation Week for details. We waited, and waited, and - sure enough, a few minutes later, there was a soft 'boom-boom' as SS1 started its supersonic re-entry. At that point, we dumped our cameras and telescopes in the car and zipped over to the east side of the airport to watch the landing. Nice thing about a gliding re-entry is we had about 20 minutes to get over to the approach to see the landing.
During setup for the landing, SS1 and all three chase planes S-turned several times to dump energy and set up for final. I was really surprised at SS1's high landing speed, although I really shouldn't have been, given its wing loading, which is not exactly like your recreational glider. High wing loading in a glider equals a hot approach and landing.
All in all, a great day. Glad we took the trouble to be there and see it happen. If you have an opportunity, and you will, go see it for yourself.
What if the gas had no mass? (Score:2, Informative)
Re:Question (Score:3, Informative)
You have when you get out of the potential well, which under the above situation you will eventually do. You will eventually reach a point where the upward velocity is greater than the local escape velocity, and it's bye-bye blue world. At no point have you had to attain a speed equal to the escape velocity at the surface, which is the claim you and TG are erroneously making.
A helicopter does nothing of the sort, and nowhere have I claimed explicitly or otherwise that it would. For a start, a helicopter is usually not in a single orbit. Of course, any motion could be described as a sum over many orbits. The helicopter has not escaped the potential well due to the Earth, so it has not escaped the Earth's gravity. The difference between the helicopter situation and that of a rocket is this: what happens when you switch the engine off? A helicopter goes smack back into the planet, a successfully launched rocket will carry on at some constant velocity away from the planet (or would do, if some git hadn't put the Sun there. In fact it starts orbiting that).
That is not necessary at all. The only situation in which your argument is even in appropriate scope is that not of a continually thrusting body such as a rocket, but that of a body that has gained momentum through an initial impulse. That is, a projectile. I'm afraid to say that Verne's "De la terre a la lune" is inaccurate in supposing that this is how astronauts are launched into space (though it is a riveting read). You are making the assumption that the body is essentially (resistive forces notwithstanding) moving in a single orbit from the beginning, and trying to derive the condition for which this orbit is unbounded. That isn't how we throw rockets into space.
We merely assume that atmospheric resistive forces may be neglected to arrive at an appropriate order-of-magnitude estimate for certain properties, because it simplifies the equation of motion. No-one's suggesting that the atmosphere needs to be removed ;-). You can calm back down now.
Re:A question for the Rocket Scientists on /. (Score:3, Informative)
Monopropellants are fantastic if you can get them to work. I paid a chemical engineer to do a literature search on propalox (propane/lox solution -- they are miscible at tankage pressures) but it turns out to be too easy to detonate. If there were some sort of stabilizer it could deliver >300 seconds as well as remaining liquid at a higher temperature/lower pressure than most cryogenics. Carmack's low specific impulse (200 seconds for his methanol/H2O2(90%) solution -- he says he may be able to get that up as high as 250 seconds if he pushes) is a serious draw-back but the simplicity he achieves is a big deal: you can buy a lot of tankage, methanol and H2O2(90%) for the money you could have spent developing and operating alternative systems.
Scaled Composite may be _talking_ 150km but the fact that they ran into control problems upon leaving the atmosphere is exactly the sort of thing I was concerned about in my first message regarding their limitation as a "space" vehicle.
I think Carmack should go for the prize. I'd be happy to be the test pilot but I doubt I'm qualified even to be spam in a can for his vehicle.
As to other techniques for 100% reuability and minimal maintanence -- well -- reusability per se is over-rated. There are reasons to believe you can manufacture rockets very cheaply if you can just get the volume up. The goal is to get the cost per mass to low earth orbit down dramatically. I've had guys who studied industrial production of automobiles and looked at the Saturn V boosters tell me that those engines aren't really any more difficult to manufacture (in terms of tolerances, materials, quality assurance, etc.) than the engine in my 1969 VW microbus, which I replaced a few years ago with a new one for under $1000. The rest is basically tankage and electronics.
If you can go single stage to orbit then you _really_ don't want reuse -- you want that tankage and mass to stay where it provides locally-available feedstocks for various proceses.