Chris Bergin - 30/8/2006 5:08 PMI can smell a book in the offering from the good Dr, if these stories are anything to go by
Pete at Edwards - 30/8/2006 8:10 PMAnd we appreciate reading them!
Rob in KC - 31/8/2006 2:36 AMAbsolutely. When is the next Pegasus launch and will it be a live event on this site?
Rob in KC - 30/8/2006 9:36 PMQuotePete at Edwards - 30/8/2006 8:10 PMAnd we appreciate reading them!Absolutely. When is the next Pegasus launch and will it be a live event on this site?
The Pegasus story, Part II Solwind is dead, long live Pegasus.
I guess I have to explain how I got embroiled with DWT and the orbital gang. Even though we both attended MIT as undergrads, DWT was a few years younger than me, and by the time he was there I had disappeared as a Research Assistant into the Black Hole of Calcutta's Cambridge branch, a.k.a. Draper Lab. SO we really didn't meet at MIT (that we can remember). In early '86 two life-changing events things happened: The Challenger accident, and I failed to get tenure at MIT.
Orbital had been started by DWT, Scott Webster and Bruce Ferguson in '82 to commercialize space. Their lead product was a privately financed and developed upper stage that would allow the Shuttle to orbit commercial communication satellites larger than those that a PAM (Payload Assist Module) could boost into GTO, but at a fraction of the cost of the larger IUS (both developed with gov. money). They raised $50M thanks to, among other instruments, one of the last "Limited R&D Partnerships" allowed under U.S. tax law. Then-hungry Martin Marietta (whose Titan line of ELV's was being driven out of business by the Shuttle), under the leadership of a young and aggressive vice-president named Pete Teets agreed to be the actual developer and builder of the "Transfer Orbit Stage" or TOS, under contract to Orbital Sciences Corporation, or "OSC" (Note: the OSC logo was designed by Scott Webster to look very similar to the NASA "worm", and many people thought it read "CSC" - we are now, very wisely, known simply as "Orbital").
After the Challenger accident, the government decided not to offer commercial launches with the Shuttle (and the USAF decided to go back to the ELV business). This spelled the doom of the TOS product line - a total of 2 were sold, both to... NASA!, and one did not even fly on the Shuttle, but on a Titan 34D. A large number of people left OSC, creating the need for, among others, a "Chief Engineer". MIT's Jack Kerrebrock was an OSC board member at the time, and he suggested to DWT to contact the soon-to-be-unemployed Assistant Professor (Third Class) Antonio Elias. I walked into the hallowed halls of OSC's Fair Lakes offices September 2, 1986. There were twenty of us there, including the three founders, the receptionist, and me. Because of attrition, though, my employee number was 40. After Ray Palladino retired, I believe that only four of those twenty still work at Orbital: DWT (Employee #1), Linda Buhl (probably #26 or so), Jim Utter (#39, joined the day before I did) and me.
My job was to supposedly direct (technically - John Mehoves was the PM) the TOS program, although, frankly, the Martin Marietta guys were doing pretty well by themselves; hire a couple dozen more engineers; and help the rest of the gang figure out what to do after TOS. Here's where the Bob Lovell smallsat idea and the "Camarillo Incident" happened. After that fiasco (see Part I of this exciting mini-series), I suggested once or twice that perhaps we could develop a small LV ourselves. DWT's response, having seen Bob Truax and others try and fail was, and I quote; "Antonio, the battlefield of small launch vehicles is littered with corpses."
One sunny day in 1987, Bob Lindberg, Bruce Ferguson and I attended a meeting convened by the Commonwealth of Virginia's Center for Innovative Technology (CIT) and a couple of universities for the purposes of planning the establishment of a CCDS ("Center for the Commercial Development of Space") a NASA creation whereby NASA would match privately-raised funds for such a beast, on the condition that it involved a local government (as in CIT), academia, and industry. The venue was the hotel on Route 28 (then a two-lane road!) midways between the Dulles access road and RT 50 which is now a Hilton (it was something else then). Unfortunately the meeting was extraordinarily disorganized, down to the starting time, the agenda, the meeting room, and the speakers. The net result was that we had a lot of free time, even when we were finally directed to a room with the inevitable tacky white tablecloths, ice water pitchers, yellow ruled paper pads and cheap hotel-logo-embossed #2 pencils.
In the resulting boredom and gentle spring afternoon sleepiness (years later Bob Lindberg claimed to remember it was April the 8th) my mind stared wandering. I remembered a conversation a few days or weeks before where someone - I wish I could remember who - mentioned the uproar that the F-15 ASAT test carried out in late '85 (September 13, to be precise) had caused because a) the non-proliferation gurus were upset at the resulting arms race escalation it would engender and b) a "perfectly good gamma-ray spectroscopy satellite" (P78-1, a.k.a. "Solwind") was the target and was destroyed. I lazily drew a rather clumsy 3-D sketch of an F-15 flying at about 80 deg flight path angle and dropping a small rocket; its nose had a small cutaway section that revealed a small, Vanguard-looking satellite. Without even thinking about the Camarillo Incident, I passed the drawing to Bob Lindberg, who raised an eyebrow and passed it to Bruce Ferguson, who also raised an eyebrow, and we started chatting about how cool it would be to build and fly such small satellites, and how inexpensive it would be, since the F-15 obviously would give the vehicle a big initial kick.
After 30 minutes of chatting the meeting still had not started, so we decided it was a lot more interesting to return to Fair Lakes and show the gang the drawing and simply walked out. At the office we found DWT and Dave Rossi talking in the corridor. Bob Lindberg shouted something like "hey, guys, Antonio has a cool idea". From that point on, we all caught air-launch fever, except poor John Mehoves, who was trying to keep the TOS program on budget and on schedule (it ended up both on budget and on schedule!!!)
Unfortunately I lost the yellow ruled paper where I drew that first sketch. The earliest sketch I have is dated May 27; it shows two rockets: a 20,000 lb "C-141 pylon-launched" with a 38" diameter fuselage, and a smaller, 6,000 lb with a 26.75" diameter. Both are three-stage solids with a very small, almost vestigial unswept wing mounted below the motor casings (see "oops" below). The payload for the 20,000-ponder is jotted down as "387 lbs" (not a bad guess after the real Pegasus was built and flown). There is a crude CG calculation. The original drawing, as well as the manually-coded 3-D simulation runs I did on my 12MHz (!) MS-DOS PC, one of two PC's owned by OSC (the other one was Jim Utter's where he crunched TOS financials) did not have a wing. The rocket would drop from the carrier aircraft at or near zero alpha, ignite, use TVC to turn at no more than 45 degrees angle of attack until near vertical, and fly to orbit. DWT used to come by my office (every 2 hours or so, it seemed) to check on the progress; each time he suggested I add a wing. My standard answer was that a wing would add drag and mass without doing anything useful - just look cool.
After about the third time DWT repeated the wing mantra, I wondered if he could have a point there. The rocket was using a significant fraction of its burn time simply canceling the descent rate and climbing back to the drop altitude. Its turning losses were double: rotating from level flight to almost 90 deg, and then back to a low flight path angle for the second stage burn and coast. I moused the simulation by adding a very, very crude and conservative wing lift and drag model. As if by magic, the losses dropped by, I seem to remember, something like 2,000 feet per second. The 27 May drawing must have been made shortly after that epiphany.
We employed at OSC a very, very talented artist by the name of Paul Hudson, whose drawings and paintings were of Bob McCall quality or even better. Not having a CAD system, I asked him to make some better-looking sketches. After verbally describing the vehicle, he produced, in about 30 minutes, a beautiful pen rendering. I started showing it to the other people when somebody, I think Dave Rossi, pointed out that the mid-mounted wing's spar appeared to cross cleanly right though the solid rocket motor case!!! I was so happy with the quality of Paul's drawing that I had failed to notice it!!! I quickly directed Paul to a) mount the wing on TOP of the rocket, b) make it a 45-degree delta (based on minimizing the travel of the center of pressure with Mach number) and c) make the nose fairing smooth, rather than his original drawing's pointy or the classical bi-conical (I worried about local separation at large angles of attack). It still had four fins (I'll explain that later.)
Sorry, no paper napkin - it was a hotel-supplied yellow ruled paper pad. An the original, as far as I know, is lost...
Next installment: A pilgrimage to the desert.
josh_simonson - 31/8/2006 3:57 AMIndeed, the tarus is alot cheaper than pegasus/lb. If you guys could repeat those performance gains with another size iteration you'd be competitive with Delta 2 and EELV in $/lb. Perhaps 3 castor 120s under or around a taurus without the pegasus-3 motor?
Unfortunately, the economics of large solids aren't that good (e.g., what ATK chargers for a GT-120 these days). Now, if we had a source of free (or at least cheap) Peacekeeper motors...
BTW, a little personal brag about the GT-120. Shortly after Pegasus first flew, while we and others were competing for the DARPA program that eventually begot Taurus, Thiokol (now ATK) was struggling with the decision to develop a commercial version of the TU-901, their Peacekeeper first stage motor (sans its nuclear-bomb-proof - literally! - features). One of their executives called me, as one of the potential customers, and asked what what I thought should be the ideal size for the commercial version (the TU-901 is about 108,000 lb.) In real time, and not much thought over "it should be a little bigger", I answered "120,000 lb" - hence the name "Castor 120", later renamed to "GT-120". (Frankly, perhaps the Lockheed people also told him 120,000 lb - great minds think alike.) The actual Castor-120 ended up a bit under 120,000lbs.
kraisee - 31/8/2006 12:52 AMThe stories have been fantastic reading, and I'd like to add my thanks to Dr. Elais for taking the time to contribute them.I do have a question though...Where does the Pegasus system go from here?Is there a bigger, newer version being conceived of? Are there concepts you're looking into?Thanks for your time,Ross B Tierney.
josh_simonson - 31/8/2006 2:57 AMIndeed, the tarus is alot cheaper than pegasus/lb. If you guys could repeat those performance gains with another size iteration you'd be competitive with Delta 2 and EELV in $/lb. Perhaps 3 castor 120s under or around a taurus without the pegasus-3 motor?
antonioe - 31/8/2006 7:02 PMInterestingly enough, some ten years later, Burt unveils a (roughly) 1/3 scale version called "White Knight"
antonioe - 30/8/2006 9:34 PMSorry, no paper napkin - it was a hotel-supplied yellow ruled paper pad. An the original, as far as I know, is lost...Next installment: A pilgrimage to the desert.
kraisee - 31/8/2006 2:28 PM Actually Spiff, that's a good point. Rutan is building a next-generation of White Knight anyway, so it's going to be a customised carrier aircraft for dropping air-launch payloads, available "off the shelf". Antonio, assuming it has sufficient carrying capacity, would the Pegasus team consider possibly using a White Knight 2 "off the shelf" and designing a booster specifically to suit it's load capacity? Ross.
Heres a Rutan design for T-Space. Would that be of the right scale to pop off something of that size???
antonioe - 31/8/2006 12:46 PM I answered "120,000 lb" - hence the name "Castor 120", later renamed to "GT-120". (Frankly, perhaps the Lockheed people also told him 120,000 lb - great minds think alike.)
I answered "120,000 lb" - hence the name "Castor 120", later renamed to "GT-120". (Frankly, perhaps the Lockheed people also told him 120,000 lb - great minds think alike.)
astrobrian - 2/9/2006 8:32 AMQuotekraisee - 31/8/2006 2:28 PM Actually Spiff, that's a good point. Rutan is building a next-generation of White Knight anyway, so it's going to be a customised carrier aircraft for dropping air-launch payloads, available "off the shelf". Antonio, assuming it has sufficient carrying capacity, would the Pegasus team consider possibly using a White Knight 2 "off the shelf" and designing a booster specifically to suit it's load capacity? Ross. Heres a Rutan design for T-Space. Would that be of the right scale to pop off something of that size???
Heres a Rutan design for T-Space. Would that be of the right scale to pop off something of that size???