BU Students Working On a Cheaper, Gentler Suborbital Rocket

Zothecula writes The International Space Station may get all the glory, but suborbital rocket flights still play a vital part in space research. The problem is that even though such flights only go to the edge of space, they are expensive, few in number, and put massive stresses on experiments. Partly funded by a Kickstarter campaign, students at Boston University are developing an inexpensive suborbital rocket for educational purposes that uses new engine designs to create a cheaper, reusable suborbital rocket that's easier on the payload.

Comments

Airship one headed in the right direction

[Anonymous Coward]

Cheaper way would be a large high altitude jet to carry the rocket to the edge of space. Use the oxygen in the air as long as possible and not carry the oxygen aboard. A maglev launcher like the Navy is experimenting with,(only bigger) have as much horsepower on the ground as possible.
Get the whole thing up to 500mph and then 500 ft up. The jet engine takes over and goes up to 60000+ ft. 700 mph, not quite mach 1.
Then the rocket can kick in and go to the station.

Re:Airship one headed in the right direction

[Solandri]

Cheaper way would be a large high altitude jet to carry the rocket to the edge of space. Use the oxygen in the air as long as possible and not carry the oxygen aboard. [...]
Get the whole thing up to 500mph and then 500 ft up. The jet engine takes over and goes up to 60000+ ft. 700 mph, not quite mach 1.
Then the rocket can kick in and go to the station.

The great irony of the space age is that is precisely what the U.S. was working on in parallel to Sputnik. Before Sputnik ever went up, clearer-thinking people analyzed the problem, and came to the same conclusion you just did - it's cheaper to strap your rocket to a plane, haul it up to 45,000 ft, and launch it into space from there.

But then the Soviets put a man into orbit, Kennedy said we should land a man on the moon by the end of the decade, and suddenly doing it quickly took precedence over doing it economically. That's led us 5 decades down the "wrong" technology path (simpler, quicker, but more expensive). And only in the last decade have we been seriously reconsidering the cheaper technology path. I often wonder where we would be if there had been no space race. Would we already have hypersonic transports taking you halfway around the world in an hour? Would space travel be more commonplace because it'd be so much cheaper?

Re:Airship one headed in the right direction

[thrich81]

Not intending to bust on you here, but this idea comes up occasionally -- that NASA screwed up by "abandoning" air-launched space planes for ICBM based capsules. Often it is from someone who "had an uncle working on it in 1958" or similar. Seems promising but the physics just don't work that well for air launches and it turns out that putting the rest of your vehicle on a big first stage to get it out of the atmosphere and on a good start for speed is very efficient. There is a huge difference in getting an X-15 to Mach 6+ and an orbital vehicle to Mach 25. Air launch just doesn't work for anything other than small payloads.

To get the Apollo lander to the moon the Saturn V had to put 260,000 lbs into low earth orbit. The biggest Boeing 747 now (in 2014) has a takeoff weight of 975,000 lbs. Look at the difference in size between the X-15 and the B-52 which carried it. There is no aircraft which is going to launch an Apollo sized payload into earth orbit. Or looking at it another way -- at burnout and jettison of the first stage of the Saturn V, the rest of the vehicle was already moving faster than the X-15 ever got to (a lot faster) and almost as high.

If air launch was really feasible, then customers would be knocking down the door at Orbital Sciences which has had their air-launch to orbit Pegasus booster in operation since 1990 and there would be an effort to build bigger versions -- there isn't. That whole X-30 program (National Aero-Space Plane) in the 90's was similar to air launched spacecraft and it didn't get anywhere.
   

Oblig

[Bovius]

I have some guesses about how they're doing their research.

http://xkcd.com/1244/

YesIKnowIt'sSuborbitalGoAway.

Gentler Suborbital Rocket

[koan]

Now with lubrication.

Reusable != cheap.

[140Mandak262Jamuna]

A solid rocket is basically a tube of propellants (oxidizer and fuel). The only precision component in there is the rocket nozzle, even that is not very expensive for solid boosters. They need vectored thrust only for a the first few seconds before the rocket attains enough air speed to make the fins produce aerodynamic forces. That thrust vectoring is easily achieved by asymmetrical blocking of the jet flow or by bleeding the jet off the compressor to feed the vernier nozzles. The economics are such that it is never economical to make them reusable. As long as we use chemicals to produce the thrust, nothing is going to be cheaper than solid rocket boosters.

Using rocket boosted ramjets and scramjets might save you the need to carry oxidizer in the lower atmosphere. That is where drag is highest. Air resistance goes as the square of the air speed. So "lazy" launch speed works only in that region of the atmosphere. These ram and scramjets are also very very simple. Reusability requirements would raise the cost of materials and engineering. If you want to save money, they should concentrate on cost and probably sacrifice reusability.