Thursday, March 31, 2011

The Saga of NASA's Heavy Lift Launcher

Last week, after years of studies and negotiations, NASA finally released a preliminary design for the new rocket that will replace the space shuttle. The new rocket will be a Shuttle-Derived Heavy Lift Vehicle, meaning that it will make maximum use of existing Space Shuttle components. Basically they will keep the Space Shuttle External tank and two Solid Rocket Boosters unchanged, remove the space shuttle, take the shuttle's three main engines and put them and the bottom of the External Tank, and put the cargo on top of the External Tank. This design is pretty much the solution proposed by the DIRECT team last year, called the Jupiter launch vehicle.

Here is a great video that shows how they are going to do it:

The NASA report outlines four different configurations for the new rocket:

The Block 0 rocket (Jupiter 130) will have two 4-segment Solid Rocket Boosters (SRB) and 3 Space Shuttle Main Engines (SSME), no second stage, and will be able to put 70 metric tonnes in orbit. This model should be operational before December 2016 and will be capable of sending the Orion space capsule (carrying up to 6 people) and some cargo to the International Space Station (IISS).

Block 1 (Jupiter 150) will use two 5-segment (longer) SRB's and 5 SSME, still no second stage and be able to put 100 mt in orbit.
Block 2 (Jupiter 253) will use two 5-segment SRB's and 5 SSME, and have a second stage with 3 J2-X engines (130 mt)
Block 3 (Jupiter 253 Heavy) is the same as Block 2 but with upgraded (HTPB composite-case) 5 segment SRB's and be able to put 150 mt in orbit.

The good news is, it will be a badass big rocket that will be able to lift between 70 and 150 tonnes in orbit, that's 3 to 6 times more than the space shuttle's cargo capacity. It will be able to send spaceships to the moon and near earth asteroids, and possibly to mars. It will enable the US to send astronauts to the International Space Station without having to rely on the Russians do so. It will also be cheap and quick to develop.

The bad news is that they chose a design that is 30 years old (The Morton-Thyokol design from 1978), is not reusable like the space shuttle, it literally scavenges old engines and solid rocket boosters from the current space shuttle fleet instead of using newer and more powerful engines and technologies like 5.5 segment SRB's or RD-68 engines (more on those later). Even in it's most advanced configuration, it will be 25% less powerful than the defunct Ares V from the Constellation Program that was cancelled last year. NASA could have done a lot better.

To really appreciate how disappointing such a design is to a space program enthusiast, let us review the many ambitious rockets that were envisioned by NASA in the last 30 years.

Morton Thiokol Design, 1978
In 1978, the Space Shuttle was just about to do its first flight, and Morton Thiokol proposed a shuttle-derived heavy rocket that was practically identical to the Jupiter rocket. In 1982, maybe realizing that a rocket so similar to the space shuttle was not ambitious enough for a nation that just won the race to the moon, NASA started working on a much more advanced concept: the X-30 National Aerospace Plane.  This truly futuristic spaceship would be able to take off and land from a conventional airport, and reach orbit without use of disposable boosters or external tanks. It would lower the cost of sending cargo to space to 1/10th what it was for the Space Shuttle.

The National Aerospace Plane

In 1993, the project was judged too expensive and was abandoned. NASA turned its focus back to a shuttle-derived heavy launcher, but this time they considered a design capable of much larger payloads: The National Launch System was to have ultimately led to a monster rocket made of a total of 6 Space Shuttle External Tanks tied together, with 16 F-1 engines (the engines used on the big Saturn V rocket) and 4 SSME. This monster would have been able to send 120 mt (metric tonnes) to Trans-Lunar Insertion trajectory  (TLI)  or 320 mt in low earth orbit !!! Another model would have used 8 Space Shuttle SRBs and 3 SSME.

But again, it was decided that these would be too expensive, so engineers went back to their drawing boards and turned their attention again to the Single Stage to Orbit concept. The result was the Venture Star, a space plane that would take off vertically and fly back and land on a runway. It would be entirely re-usable.

The Venture Star

The Venture Star encountered technological problems and was cancelled in 2001. About $1 billion had been spent on it.
Ares V rocket

Then in 2005, NASA showed a newfound interest in the moon, and decided to launch the Constellation Program, an exciting and ambitious return to the moon, with plans to ultimately setup a permanently inhabited outpost on the moon! Two new rockets would be built for this, the Ares I and Ares V. The small Ares I would launch the 4 astronauts in the Orion capsule and the giant Ares V, capable of putting 188 mt in orbit, would launch the moon lander and Earth Departure Stage rocket. The crew would rendez-vous with the moon lander and EDS in earth orbit before leaving for the moon. The Ares I was a small, simple and man-rated (safe for humans) rocket, while the Ares V would be a giant cargo lifter that would use a larger fuel tank (33 ft diameter versus 27.5 for Jupiter), six RS-68 engines and two 5.5 segment SRB. The RS-68 are 55% more powerful than the SSME but are less expensive because they are not man-rated and they are not designed to be reusable.

Unfortunately, in October 2010 President Obama cancelled the Constellation Program, citing budgetary constraints. By that time NASA had already spent $10 billion dollars on it. Other designs had been proposed over the years, like the Shuttle-C, which was basically a shuttle without wings that would do a one way trip to orbit, or in-line designs with engine pods on each side of the main  fuel tank.
Constellation's Altair Moon Lander                                             


                                                                               Side-mounted engine pods on SD HLV

Saturn V, Space Shuttle, Ares I, Ares V and Ares IV

Various Heavy Lift projects. From the right: Ares V, Ares I, Ares IV, Jupiter 246 and Jupiter 130

The justification for cancelling all these amazing programs is that they cost too much, that the U.S. can't afford it. Really? Let's put things in perspective here. The Constellation Program was estimated to cost $97 billion over 12 years, so about $8 billion a year.  The U.S. GDP is $15,000 billion dollars. So the program would have cost 0.05% of GDP. That's one half of one tenth of one percent. That's $26 per person per year. 7 cents per day.
Americans spend $13 billion a year on porn!! They spent $3.2 billion a year on pet grooming!! $5 billion a year on popcorn at the movies! $4 billion on luxury yachts! And we don't have enough money to send a man on the moon? No, it's not a question of money, it's a question of priority. People are just not interested in space exploration anymore.

Furthermore, if NASA hadn't cancelled and started new projects every time a new administration came to the White House, we would have had the Jupiter rocket 30 years ago!

So now they are going to develop a cheap-ass rocket that uses old RS-25 SSME engines, not because they are better, but because we already have a stock of 15 of them on the Space Shuttles...

Well, at least we will have something. Even if it's a cheap-ass rocket, I'm still pretty excited about it. They are planning to send manned visits to nearby asteroids with it, which is pretty cool. Not as cool as a moon base, but still pretty cool... And right now I just hope that they will stick to that plan and not cancel the whole thing yet again...


UPDATE: On September 14th, 2011 NASA officially unveiled the design of the new rocket, now called the Space Launch System (SLS). See my new post for more information. 

1 comment:

  1. Thanks for your share! very impressive!



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